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Introduction: Osteomyelitis can occur at various osseous locations and commonly presents in the emergency department (ED). The incidence of osteomyelitis is 21.8 cases per 100,000 persons annually.1 Hematogenous osteomyelitis typically occurs in the vertebrae; however, it may seldomly occur in the manubrium. Hematogenous osteomyelitis can be seen in patients with complicated thoracic surgery, radiation, fracture, diabetes, immunosuppression, steroid therapy, and malnutrition.2 Because signs and symptoms of osteomyelitis may be nonspecific, clinicians must have high suspicion based on history and physical. Workup should include identifying the source, imaging, and surgical cultures.Case Report: A 60-year-old male with hypertension and diabetes presented with atraumatic right shoulder and chest pain. The patient presented twice to the ED for clavicle pain five days prior. Computed tomography (CT) of the chest detected osseous infection of the manubrium and upper sternum, right clavicle, and mediastinal phlegmon. A CT of the abdomen and pelvis revealed osteomyelitis and discitis of the 12th thoracic and first lumbar vertebral body with gas at the psoas muscle, as well as sigmoid diverticulitis with colovesicular fistula. The patient was started on broad spectrum antibiotics and 1,500 milliliters of lactated Ringer’s in the ED. After evaluation by cardiothoracic surgery, the patient was taken to the operating room for neck exploration, incision/drainage, manubriectomy, and right sternoclavicular joint resection. Surgical, blood, urine, and respiratory cultures grew Klebsiella pneumoniae. After a 34-day hospital course, the patient was discharged on two weeks of oral levofloxacin and follow-up appointments with cardiothoracic surgery and infectious disease. The patient had good prognosis and recovery.Conclusion: Hematogenous osteomyelitis to the manubrium is rare and may present with only chest pain. It is important to consider other sources that seed in the manubrium and imaging to evaluate multisite infection. Treatment should include intravenous antibiotics and/or surgical intervention for debridement with washout or manubriectomy.

Polymeric composite materials are in great demand in biomedical and water treatment applications. This is because they possess distinct characteristics and can fulfill specific biomedical needs, in addition to their ability to degrade dyes. This study successfully synthesized sustainable strontium titanate (STO) particles with an average size of 120 nm using the solid-state method. When these STO particles were mixed into a PCL-based polyurethane matrix, the matrix became hydrophilic with a contact angle of 58.60° and its mechanical strength enhanced by 320%. The morphology and surface roughness of the films were determined using FESEM and AFM techniques. The antibacterial studies of polymeric composites film against E. coli, Klebsiella pneumonia, and S. aureus , showing good zone growth, and showing enhanced swelling properties of 270% for wound healing and biomedical applications. The photocatalytic performance of the STO by degrading Methyl Orange (MO) and Congo Red (CR) under UV light, achieving degradation efficiencies of 92.25% for MO and 62.5% for CR over 150 min. These findings suggest that PU scaffolds and STO are suitable for biological and water treatment in industrial applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This investigation aimed to study the effects of ZnO-added fluorophosphate glass on in vitro degradation, apatite-forming ability, cytotoxicity, antioxidant efficacy, and antibacterial activity. In this regard, fluorophosphate glasses with varying zinc oxide (ZnO) content (0, 1, 2, 4, and 8 mol%) were synthesized by the standard melt quenching technique and subsequently in vitro degradation of the glass samples was analyzed by water solubility test. The apatite-forming ability of the glasses was studied by simulated body fluid (SBF) immersion analysis. Variations in the elemental and structural properties of the glasses before and after SBF immersion were assessed using an X-ray diffractometer, a Fourier transform infrared spectrometer, and a scanning electron microscope coupled with energy-dispersive X-ray spectrometer. The cytotoxicity assessment for ZnO-added fluorophosphate glasses was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The antioxidant efficacy of the glass samples was evaluated using 2,2-diphenyl-1-picrylhydrazyl assay. Variations were observed in lower concentrations of ZnO compared to higher concentrations in mechanical, structural, and biological properties. Amongst the concentrations, 2 mol% ZnO-added fluorophosphate glass demonstrated superior antioxidant activity compared to the zinc-free fluorophosphate glass. The optimized 2 mol% of ZnO was evaluated against different bacterial strains such as Escherichia coli , Klebsiella pneumonia , Proteus vulgaris , Staphylococcus epidermidis , Pseudomonas aeruginosa , and Staphylococcus aureus using the agar diffusion method. A distinct transparent inhibitory zone was observed against all the bacterial strains, following exposure to the 2 mol% of ZnO containing fluorophosphate glass compared to the zinc-free glass sample. These findings suggest that 2 mol% of ZnO containing fluorophosphate glass is well-suited for biomedical applications involving cellular activity. [ABSTRACT FROM AUTHOR]

Novel 2-imino-6-(aryldiazenyl)-2H-chromene-3-carboxamides 6a–e, 2-amino-4H-cyclopenta or benzo[b]thiophene-3-carboxamides 10a,b, 2,7-diaminopyrazolo[1,5-a]pyrimidine-6-carboxamides 13a–e, pyrimidine-5-carboxamides 14, 15 and 3-amino-1H-pyrazole-4-carboxamide 16 were synthesized from the reaction of 2-cyano-N-(1,3-dihydroxy-2-(hydroxyl-methyl) propan-2-yl) acetamide 2 with 4-arylazosalicylaldehydes 5a-e, cyclopentanone and/or cyclohexanone, guanidine derivatives and hydrazine hydrate, respectively. Some new compounds were evaluated for antibacterial activity in vitro, and exhibited good efficacy compared to gentamicin. Compound 4c showed greater activity against gram negative bacteria (Klebsiella pneumonia and Pseudomonas aeruginosa) than standard antibiotic. Compound 4c with two withdrawing groups also showed the higher activity (38.7 ± 0.6) against fungi (Candida albicans) than the Nystatin (20 ± 0.5). On the other hand, compounds 13a, 13c, and 13e have strong cytotoxic activity among the tested compounds in the three selected cancer cell lines (HePG2, MCF7 and Hela). Physicochemical characterization by Swiss ADME predication was also performed for some synthesized compounds exhibiting better biological and antimicrobial properties. [ABSTRACT FROM AUTHOR]

In an endeavor to invent new antimalarial and antimicrobial agents, a series of coumarin bound 1,4-disubstituted 1,2,3-triazoles was synthesized through Cu(I)-promoted click reaction between coumarin bound terminal alkynes, that is, 4/7-(prop-2-yn-1-yloxy)-2H-chromen-2-one and 2-azido-N-arylpropanamides. The synthesized 1,2,3-triazoles were characterized by FTIR,1H NMR,13C NMR, and HRMS techniques and were assessed for in vitro antimalarial activity against Plasmodium falciparum as well as in vitro antimicrobial activity against four bacterial strains (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Klebsiella pneumoniae) and two fungal strains (Candida albicans, Aspergillus niger). Compound 7o [(N-(4-fluorophenyl)-2-(4-(((2-oxo-2H-chromen-7-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)propanamide)] displayed better activity against P. falciparum while compound 7y [(N-(3-nitrophenyl)-2-(4-(((2-oxo-2H-chromen-7-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)propanamide)] displayed excellent activity against all the tested bacterial and fungal strains, amongst the synthesized triazoles. Also, the molecular docking studies of the most potent compounds against DNA gyrase (S. aureus) were also performed to have an insight on binding interactions. [ABSTRACT FROM AUTHOR]

An increasing number of drug-resistant bacteria have been identified recently. In particular, drug-resistant bacteria have been linked to unfavorable prognoses in patients with bacteremia, highlighting the need for rapid testing. Our previous studies have focused on the utility of a drug susceptibility testing microfluidic (DSTM) method using microfluidic channels. A system with this DSTM method for screening for β-lactamases can rapidly detect extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs). In this study, we have evaluated the clinical utility of pre-treatment for screening positive blood cultures using the DSTM method. A total of 178 positive blood cultures and five simulated samples of MBL-producing bacteria were prepared at Kochi University Hospital, Japan. The pretreatment consisted of a two-step centrifugation. The obtained sediments were screened with the DSTM method for the production of β-lactamase based on morphological changes in the bacteria after 3 h of incubation. The pretreatment functioned properly for all samples. Of the 25 ESBL samples, 21 were positive for ESBLs. Four false-negative samples, all obtained from the same patient, contained CTX-M-2 enzyme-producing Proteus mirabilis and showed insusceptibility to an ESBL inhibitor. The simulated samples prepared for MBL screening were positive for MBLs. When combined with a method for rapidly identifying bacterial species, DSTM may enable patients with bloodstream infections to start receiving appropriate treatment within 4 h after positive blood cultures are screened. [ABSTRACT FROM AUTHOR]

Carbapenem-resistant Enterobacterales (CRE) have become a global threat, with colistin being the last resort for treatment. CLSI and EUCAST recommend broth microdilution (BMD) as the reference method for colistin susceptibility testing. Nordmann and Poirel have developed a simple and rapid Polymyxin NP test as an alternative to BMD for screening of colistin-resistant Enterobacterale (CoRE) isolates. This study aimed to evaluate the performance of the colistin rapid NP (CRNP) test for the detection of colistin resistance. CRNP test was performed on thirty-one clinical Enterobacterales isolates [ Klebsiella pneumoniae (21), Enterobacter spp , (9) and Escherichia coli (1), which were resistant to Colistin by the reference BMD method. The results of the NP test were interpreted after 4hr by the change in color of NP solution (original orange to yellow as a result of bacterial growth) and compared with that of BMD. The CRNP test could accurately detect 26/31 of the colistin resistant Enterobacterale isolates, and thus had an overall categorical agreement of 83.8%. Out of thirty-one CoRE isolates, five Enterobacter spp. 5/31 (16.1%) could not be detected by the CRNP test giving a false-negative result. Excluding those five Enterobacter spp. the categorical agreement (CA) of the CRNP test with BMD was 100%. The overall very major error (VME) of the CRNP test was 16% but decreased to < 3% when Enterobacter spp. (5) were excluded. The CRNP test is technically less demanding, yields faster results compared to the reference BMD method, and has 100% agreement with reference BMD in Enterobacterales except for Enterobacter spp. [ABSTRACT FROM AUTHOR]

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Introduction: Infections caused by Klebsiella pneumoniae carbapenemase (KPC) pose a significant clinical challenge due to increasing antibiotic resistance. This study analyzes the effectiveness of ceftazidime/avibactam treatment for KPC infections, focusing on 30-day mortality and comparing results with control groups treated with different antibiotics. Material and methods: We conducted a retrospective analysis of six cohort studies, comparing thirty-day mortality in patients treated with ceftazidime/avibactam with control groups using other antibiotics. The studies included patients infected with KPC, and the analysis focused on therapeutic effectiveness. Aim of the study: The aim of the study is to compare the results in terms of 30-day mortality in groups treated with ceftazidime/avibactam compared to control groups using different antibiotics. Conclusions: Data analysis from various studies revealed varied 30-day mortality outcomes in groups treated with ceftazidime/avibactam compared to control groups using different antibiotics. Ceftazidime/avibactam proved to be more effective in all studies, reducing mortality rates compared to other treatment regimens. We emphasize that emerging antibiotic resistance, especially in the case of KPC, requires a comprehensive therapeutic approach. Despite promising ceftazidime/avibactam results, factors such as overall patient health and treatment delays may influence final therapy outcomes. We also highlight controversies regarding combination therapy vs. monotherapy, necessitating further research. Our work underscores the importance of monitoring the effectiveness of KPC infection treatment and exploring new therapeutic strategies. Further clinical studies are essential to develop a fuller understanding and optimal therapeutic protocols in the face of the growing antibiotic resistance problem. [ABSTRACT FROM AUTHOR]

Background: Klebsiella pneumoniae is a significant global public health burden, especially in low-income countries and regions with fragile healthcare infrastructures, due to its ability to cause severe infections, increase mortality rates, and its rising antimicrobial resistance. This study aimed to estimate the proportion of multidrug-resistant (MDR) K. pneumoniae infections and identify associated risk factors. Methods: Data were retrospectively collected from three academic hospitals in Beirut, Lebanon, between January 2021 and September 2023 using a standardized form. Binary logistic regression was used to determine risk factors associated with MDR, extended-spectrum beta-lactamase (ESBL)-producing, and carbapenem-resistant K. pneumoniae (CRKP) infections. Results: Out of 2,655 K. pneumoniae cases, 410 met the inclusion criteria. The primary infection sources were the urinary tract (58.3%) and the respiratory tract (12.4%). Among the isolates, 61% were MDR K. pneumoniae, with 7.3% being extensively drug-resistant, and 0.5% pandrug-resistant. Additionally, 36.8% were ESBL-producing, while 6.3% were CRKP. Predictors significantly associated with MDR K. pneumoniae infections included male sex (adjusted odds ratio [AOR] = 3.46, 95% CI = 1.01–11.86, P = 0.04), recent antibiotics use (AOR = 4.52, 95% CI = 1.65–12.36, P = 0.003), and recent cancer chemotherapy (AOR = 3.43, 95% CI = 1.25–9.42, P = 0.01). ESBL-producing infections were associated with age ≥ 65 years, higher Charlson Comorbidity Index (CCI), and recent antibiotic use. CRKP infections were linked to male sex, prior antibiotic use, and longer hospital stays prior to infection (all P < 0.05). Conclusions: MDR K. pneumoniae infections are steadily rising in Lebanon, along with an increase in ESBL-producing and CRKP cases. The main risk factors for MDR K. pneumoniae infections were male sex, recent antibiotic use, and cancer chemotherapy. ESBL-producing infections were associated with advanced age, higher CCI, and recent antibiotic use, while CRKP infections were linked to male sex, prior antibiotic use, and prolonged hospital stays. This situation is further exacerbated by inadequate healthcare infrastructure and suboptimal national surveillance. Strengthening local surveillance and implementing effective antibiotic stewardship programs are critical to managing this growing threat.. [ABSTRACT FROM AUTHOR]

Background: Daycare centres play a critical role in early childhood development but are high-risk environments for infectious disease transmission due to close physical contact, shared toys, inadequate hygiene, and poor ventilation. These risks are especially concerning in low- and middle-income countries (LMICs) like Nigeria, where resources for infection control may be limited. This study aimed to identify and characterise virulence genes in bacterial isolates from daycare centres in Ile-Ife, Nigeria, to assess infection risks. Methods: Between November 2017 and July 2019, 233 samples were collected from 76 children, 33 daycare workers, and 124 fomites in 17 daycare centres. The bacterial isolates were analysed using conventional PCR and RAPD analysis to detect the presence of virulence genes. The frequency of crucial virulence genes and the prevalence of each bacterial species were recorded. Results: Key virulence genes were detected, including fimH in Klebsiella species (22.73% of Gram-negative isolates), algD in Pseudomonas aeruginosa (50%), and icaA and cna in Staphylococcus aureus (16.67%). Staphylococcus aureus was the most prevalent species (35%), followed by Klebsiella (28%) and Pseudomonas aeruginosa (20%). Conclusion: This study highlights the presence of virulent bacterial pathogens in daycare environments, posing a severe infection risk to children. To mitigate these risks, it is essential to implement enhanced infection control measures, such as regular microbial screening, improved hand hygiene practices, and disinfection protocols for fomites. Training programs for daycare workers on hygiene practices and routine monitoring could also significantly reduce infection transmission. These interventions are vital for safeguarding the health of daycare children in Nigeria and similar settings globally. [ABSTRACT FROM AUTHOR]

This research comprehensively investigates the epidemiological features and pathogen profile of acute respiratory infections (ARI) in Shihezi City, Xinjiang. A pivotal aspect of this study is the construction of a Bayes discriminant function for principal pathogen infections. This innovative methodology aims to furnish a robust scientific basis for the prevention and clinical management of ARI, potentially guiding more effective strategies in both public health and clinical settings. We compiled and examined data from January 2020 to June 2023, pertaining to patients admitted with acute respiratory infections at the First Affiliated Hospital of Shihezi University. This investigation focused on discerning patterns in epidemiology and pathogen etiology. Among 2110 cases of acute respiratory infections (ARI), 1736 underwent pathogenetic testing. Of these, 595 cases tested positive for at least one pathogen, marking a positivity rate of 34.27%. Viral detections, at a rate of 27.47%, were notably higher than bacterial detections, which stood at 6.51%. The most prevalent viruses identified were Human respiratory syncytial virus (hRSV), Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2), and Human adenovirus (HAdV), while the dominant bacterial pathogens included Klebsiella pneumoniae, Haemophilus influenzae, and Staphylococcus aureus. Co‐infections were observed in 76 cases, accounting for 12.77% of positive diagnoses, predominantly involving hRSV in conjunction with other pathogens. In cases of acute bronchiolitis, hRSV was the most frequent pathogen, contributing to 23.10% of such cases. Similarly, in severe pneumonia cases, SARS‐CoV‐2 was predominant, accounting for 25.4% of these infections. The group with bacterial positivity exhibited elevated levels of C‐reactive protein (CRP, 19.17 mg/L) and neutrophilic granulocyte percentage (NE%, 54.7%). The Bayes discriminant function demonstrated an initial validation accuracy of 74.9% and a cross‐validation accuracy of 63.7%. The study underscores that hRSV, SARS‐CoV‐2, and HAdV are the primary pathogens in acute respiratory infections in the Shihezi region. Pathogen susceptibility exhibits variation across different age groups, with a higher pathogen detection rate in children compared to adults. The Bayes discriminant function shows significant promise in the classification and diagnosis of major pathogenic infections. [ABSTRACT FROM AUTHOR]

Background: Ongoing studies have revealed the global prevalence of severe infections caused by the hypervirulent strains of Klebsiella pneumoniae (K. pneumoniae). Meanwhile, the World Health Organization and the Centers for Disease Control declared carbapenem-resistant K. pneumoniae as an urgent public health threat, requiring swift and effective action to mitigate its spread. Low- and middle-income countries are severely impacted by such devastating infectious diseases owing to the ill implementation of antimicrobial practices and infection control policies. Having both hypervirulence and carbapenemase gene determinants, the emergence of convergent hypervirulent carbapenem-resistant K. pneumoniae is now being reported worldwide. Methods: In this study, we sequenced 19 carbapenemase-producing K. pneumoniae strains recovered from various clinical specimens. Additionally, we evaluated the phenotypic antimicrobial susceptibility to multiple antimicrobial classes using the VITEK2 automated system. Utilizing the sequencing data, we characterized the sequence types, serotypes, pangenome, resistance profiles, virulence profiles, and mobile genetic elements of the examined isolates. We highlighted the emergence of high-risk clones carrying hypervirulence genetic determinants among the screened isolates. Results: Our findings revealed that all carbapenem-resistant isolates exhibited either extensive- or pan-drug resistance and harbored multiple variants of resistance genes spanning nearly all the antimicrobial classes. The most prevalent carbapenemase genes detected within the isolates were blaNDM−5 and blaOXA−48. We identified high-risk clones, such as ST383-K30, ST147-K64, ST11-K15, and ST14-K2, which may have evolved into putative convergent strains by acquiring the full set of hypervirulence-associated genetic determinants (iucABCD, rmpA and/ or rmpA2, putative transporter peg-344). Additionally, this study identified ST709-K9 as a high-risk clone for the first time and uncovered that capsule types K15 and K9 carried hypervirulence genetic determinants. The most frequent Inc types found in these isolates were Col440I, IncHI1B, and Inc FII(K). Conclusion: This study highlights the emergence of high-risk, extensively carbapenem-resistant K. pneumoniae strains co-carrying hypervirulence determinants in Egyptian clinical settings. This poses an imminent threat not only to Egypt but also to the global community, underscoring the urgent need for enhanced surveillance and control strategies to combat this pathogen. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae is a common pathogen capable of causing a wide range of infections. Antibiotic resistance complicates treatment of these infections significantly. We are comparing resistance levels and genotypes among two collections of K. pneumoniae clinical isolates from Alexandria Main University Hospital (AMUH). We used disc diffusion and Minimum Inhibitory Concentration (MIC) by microbroth dilution to assess resistance levels and performed whole genome sequencing (WGS) to describe multilocus sequence types (MLST) and resistance gene presence. Among a collection of 56 K. pneumoniae clinical isolates (19 from 2019 to 37 from 2021), multidrug resistance (MDR) was 33% and 10%, extended drug resistance (XDR) was 24% and 46% and pan-drug resistance (PDR) was 43% and 43%, respectively. We identified 15 MLST STs including two novel types (ST-6118 and ST-6119). ST-101 and ST-383 were common between the two collections; ST-101 was the most common genotype in 2019 (28.6%) and ST-147 was most common in 2021 (25%). Ampicillin/sulbactam, amikacin, cefepime, ceftriaxone and ertapenem MICs were significantly higher in 2021. Prevalence of aph(3') – Ia, aph(3')-VI, mphA was significantly higher in 2021. The increasing resistance levels and the persistence of some MDR/XDR genotypes is concerning. Understanding mechanisms of resistance will inform infection control and antimicrobial stewardship plans to prevent evolution and spread of XDR and PDR strains. [ABSTRACT FROM AUTHOR]

Phages and phage-encoded lytic enzymes are promising antimicrobial agents. In this study, we report the isolation and identification of bacteriophage KP2025 from Klebsiella pneumoniae. Bioinformatics analysis of KP2025 revealed a putative endolysin, LysKP213, containing a T4-like_lys domain. Purified LysKP213 was found to be highly thermostable, retaining approximately 44.4% of its lytic activity after 20 h of incubation at 95°C, and approximately 57.5% residual activity after 30 min at 121°C. Furthermore, when administered in combination with polymyxin B or fused at the N-terminus with the antimicrobial peptide cecropin A (CecA), LysKP213 exhibited increased antibacterial activity against Gram-negative pathogens, including K. pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Escherichia coli, both in vitro and in vivo. These results indicated that LysKP213 is a highly thermostable endolysin that, when combined with or fused with an outer membrane permeabilizer, has enhanced antibacterial activity and is a candidate agent for the control of infections by Gram-negative pathogens. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the presence of ESKAPE organisms on the hands of students working in the intensive care unit (ICU) at a veterinary academic hospital. Methods: A cross-sectional study was conducted among students working in an ICU at a veterinary academic hospital in South Africa. Students were sampled before the start of the ICU shift using a modified glove-juice method. Standard microbiological techniques and a series of polymerase chain reaction (PCR) assays were used to identify and characterize the bacteria. All the isolates were tested for resistance against a specific panel of antibiotics using the disk diffusion method. Proportions of bacterial species and their antimicrobial-susceptibility profiles were calculated. Results: At screening, all the veterinary students (n = 62) carried at least one of the ESKAPE organisms on their hands. Escherichia coli was the most isolated organism (76%, 47/62), followed by P. aeruginosa (48%, 30/62), A. baumannii (47%, 29/62), E. faecium (35%, 22/62), K. pneumoniae (27%, 17/62), and S. aureus (24%, 15/62). A reduced proportion of isolates were recovered from the samples, E. coli (26%, 12/47), E. faecium (23%, 5/22), P. aeruginosa (43%, 13/30), A. baumannii (24%,7/29), K. pneumoniae (41%, 7/17), and S. aureus (20%, 3/15). Most of the organisms showed a high proportion of resistance to at least one antibiotic. Multidrug resistance was reported among just over half (56%, 5/9) of E. coli, 40% (2/5) of E. faecium, 100% (13/13) of P. aeruginosa, and 33% (1/3) of S. aureus isolates. Conclusion: Students working in the ICU carry several organisms belonging to the ESKAPE group of organisms before contact with patients. Moreover, MDR resistance was common among this group of organisms. The findings of the present study underscore the importance of infection prevention and control (IPC) strategies to help reduce the likelihood of the spread of these organisms to personnel, owners, family members, and patients. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae is among the most important Gram-negative pathogens that can cause serious nosocomial infections. The emergence and prevalence of hypervirulent carbapenem-resistant K. pneumoniae (Hv-CRKP) pose a significant challenge to public health. In this study, we characterized thirty carbapenem-resistant K. pneumoniae (CRKP) strains from a tertiary care hospital in Sichuan province, China, by whole-genome sequencing and genome analysis. These strains were all highly resistant to carbapenem but remained susceptible to tigecycline. Of the 30 tested CRKP strains, 23 were positive for blaKPC−2 and seven for blaNDM−5. These blaKPC−2-positive strains all belonged to ST11, while blaNDM−5-positive strains belonged to five distinct STs. Phylogenetic analysis revealed a predominant intra-hospital transmission of ST11-KL64 in KPC-2-producing CRKP, and that both clonal and horizontal transmission of blaNDM−5 have occurred among NDM-5-producing CRKP strains in this hospital. Hypervirulence genes were commonly detected in the CRKP. The prevalent pLVKP-like plasmid and ICEKp seem to have contributed largely to the transmission of virulence genes in them. blaNDM−5 was located on highly similar IncX3 plasmids in the collected strains, and its truncated vision was highlighted. blaKPC−2 was primarily carried by IncFII/IncR plasmids in our collection. At least two IncFII/IncR plasmid subtypes were identified, exhibiting high similarity to many previously reported blaKPC−2-bearing plasmids from different parts of China. The findings provide an expanded knowledge of the genetic characteristics of CRKP, the transmission pattern of carbapenem-resistance genes, and also the convergence of Hv-CRKP. [ABSTRACT FROM AUTHOR]

The regulatory role of zinc in bone formation extends to the activation of proteins associated with bone homeostasis. Furthermore, copper is well known for its antibacterial properties. This dual function underscores the significance of zinc and copper in maintaining a balance of bone structure and function. In light of the aforementioned, zinc sulphide/copper oxide nanocomposites were created in this instance using a straightforward coprecipitation technique. Copper oxide was used as a nanocomposite to improve the structural, morphological, and biological performance of zinc sulphide nanoparticles. The X-ray diffraction pattern confirmed a transformation in the crystal structure from cubic to rhombohedral, along with increase in intensity. Fourier transforms infrared analysis indicated the presence of functional groups. Scanning electron microscopy images demonstrated a morphological shift from non-uniform to distinct spherical nanoparticles, impacting the enhancement of material properties. The pathogenic activity of the zinc sulphide/copper oxide nanocomposites was tested against nine bacterial strains. In antimicrobial testing, zinc sulphide/copper oxide nanocomposites showed promising results, particularly against Klebsiella pneumoniae (zone of inhibition: 14 mm at 100 µg/mL compared to 7 mm by standard) and Escherichia coli (zone of inhibition: 11 mm at 100 µg/mL compared to 10 mm by standard) after 24 h with zone of inhibition matching or exceeding that of the standard (chloramphenicol). Zinc sulphide nanoparticles and zinc sulphide/copper oxide nanocomposites were evaluated for their antifungal activity against fungal stains from Trichophyton rubrum, Aspergillus niger, and Aspergillus flavus. After a 24-h period, it was discovered that zinc sulphide/copper oxide nanocomposites were effective against Aspergillus flavus (zone of inhibition: 19.4 mm at 100 µg/mL compared to 6.3 mm by standard) at all concentrations (25–100 mg/mL), with zones of inhibition identical to or greater than those of the standard (fluconazole). Certainly, based on these results, zinc sulphide/copper oxide nanocomposites could be promising materials for drug delivery. Clinical trial registration: Not applicable. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) poses a significant global One Health challenge that causes increased mortality and a high financial burden. Animal production contributes to AMR, as more than half of antimicrobials are used in food-producing animals globally. There is a growing body of literature on AMR in food-producing animals in African countries, but the surveillance practices across countries vary considerably. This pilot study aims to explore the potential of wastewater and environmental surveillance (WES) of AMR and its extension to the veterinary field. Floor drainage swab (n = 18, 3/abattoir) and wastewater (n = 16, 2-3/abattoir) samples were collected from six South African abattoirs that handle various animal species, including cattle, sheep, pig, and poultry. The samples were tested for Extended-Spectrum Beta-Lactamase (ESBL) and Carbapenemase-producing Enterobacterales, Methicillin-Resistant Staphylococcus aureus (MRSA), Vancomycinresistant Enterococci (VRE), and Candida auris by using selective culturing and MALDI-TOF MS identification. The phenotype of all presumptive ESBL-producing Escherichia coli (n = 60) and Klebsiella pneumoniae (n = 24) isolates was confirmed with a disk diffusion test, and a subset (15 and 6 isolates, respectively), were further characterized by whole-genome sequencing. In total, 314 isolates (0-12 isolates/sample) withstood MALDI-TOF MS, from which 37 species were identified, E. coli and K. pneumoniae among the most abundant. Most E. coli (n = 48/60; 80%) and all K. pneumoniae isolates were recovered from the floor drainage samples, while 21 presumptive carbapenem-resistant Acinetobacter spp. isolates were isolated equally from floor drainage and wastewater samples. MRSA, VRE, or C. auris were not found. All characterized E. coli and K. pneumoniae isolates represented ESBL-phenotype. Genomic analyses revealed multiple sequence types (ST) of E. coli (n = 10) and K. pneumoniae (n = 5), including STs associated with food-producing animals globally, such as E. coli ST48 and ST10 and K. pneumoniae ST101. Common beta-lactamases linked to food-producing animals, such as blaCTX-M-55 and blaCTX-M-15, were detected. The presence of food-productionanimal-associated ESBL-gene-carrying E. coli and K. pneumoniae in an abattoir environment and wastewater indicates the potential of WES in the surveillance of AMR in food-producing animals. Furthermore, the results of this pilot study encourage studying the topic further with refined methodologies. [ABSTRACT FROM AUTHOR]

The global dissemination of multi-drug resistant (MDR) pathogenic bacteria requires the rapid research and development of alternative therapies that can support or replace conventional antibiotics. Among MDR pathogens, carbapenem-resistant Klebsiella pneumoniae (CR-Kp) are of particular concern due to their extensive resistance profiles, global dissemination in hospital environments, and their major role in some life-threatening infections. Phages, or some of their components, are recognized as one of the potential alternatives that might be helpful to treat bacterial infections. In this study, we have isolated and characterized four lytic bacteriophages targeting K. pneumoniae strains of Sequence Type (ST) 307 or ST147, two predominant high-risk clones of CR-Kp. Phages, designated vB_KpS_GP-1, vB_KpP_GP-2, vB_KpP_GP-4, and vB_KpP_GP-5, were isolated from sewage wastewater samples. The vB_KpS_GP-1 phage was a siphovirus unable to establish lysogeny with its host, while the other three were podoviruses. While 85.7% of K. pneumoniae strains of ST307 were selectively lysed by the phages vB_KpS_GP-1 or vB_KpP_GP-5, the other two phages were able to lyse all the tested strains of ST147 (n = 12). Phages were stable over a broad pH and temperature range and were characterized by burst sizes of 10-100 plaque forming units and latency periods of 10-50 minutes. Genome sequencing confirmed the absence of antibiotic resistance genes, virulence factors or toxins and revealed that two phages were likely members of new genera. Given their strictly lytic nature and high selectivity towards two of the major high-risk clones of K. pneumoniae, cocktails of these phages could represent promising candidates for further evaluation in in vivo experimental models of K. pneumoniae infection. [ABSTRACT FROM AUTHOR]

Hypervirulent K. pneumoniae (hvKp) have emerged as clinically important pathogens, posing a serious threat to human health. RfaH, a transcriptional elongation factor, has been regarded as implicated in facilitating the transcription of long virulence operons in certain bacterial species. In K. pneumoniae, RfaH plays a vital role in promoting CPS synthesis and hypermucoviscosity, as well as mediating bacterial fitness during lung infection. In this study, we aim to conduct a systematic investigation of the roles of rfaH in the survival, dissemination, and colonization of hvKp through in vitro and in vivo assays. We found that bacterial cells and colonies displayed capsule -deficient phenotypes subsequent to the deletion of rfaH in K. pneumoniae NTUH-K2044. We confirmed that rfaH is required for the synthesis of capsule and lipopolysaccharide (LPS) by positively regulating the expression of CPS and LPS gene clusters. We found that the ΔrfaH mutant led to a significantly decreased mortality of K. pneumoniae in a mouse intraperitoneal infection model. We further demonstrated that the absence of rfaH was associated with slower bacterial growth under conditions of low nutrition or iron limitation. ΔrfaH displayed reduced survival rates in the presence of human serum. Besides, the engulfment of the ΔrfaH mutant was significantly higher than that of NTUH-K2044 by macrophages in vivo, indicating an indispensable role of RfaH in the phagocytosis resistance of hvKp in mice. Both mouse intranasal and intraperitoneal infection models revealed a higher bacterial clearance rate of ΔrfaH in lungs, livers, and spleens of mice compared to its wild type, suggesting an important role of RfaH in the bacterial survival, dissemination, and colonization of hvKp in vivo. Histopathological results supported that RfaH contributes to the pathogenicity of hvKp in mice. In conclusion, our study demonstrates crucial roles of RfaH in the survival, colonization and full virulence of hvKp, which provides several implications for the development of RfaH as an antibacterial target. [ABSTRACT FROM AUTHOR]

Objective. The red rhizome of Angiopteris helferiana has been used widely to treat muscle fatigue, bone pain, and skin infection in Nepal. However, scientific evidence for its bioactive compounds and their bioactivities was lacking till January, 2024. Therefore, we investigated to validate and advance the further use and development. Methods. Column chromatography, including MCI gel CHP20P, Sephadex LH‐20, ODS, and Silica gel, was used for the isolation of compounds from 70% methanol extract of A. helferiana rhizomes. The isolated compounds were evaluated for their TLC‐based antioxidant and antibacterial activity against Staphylococcus aureus, Klebsiella pneumonia, Escherichia coli, and Pseudomonas aeruginosa by adopting the agar well diffusion protocol. Furthermore, in silico molecular docking against the penicillin binding protein of E. coli (PBP1b, PBP2, and PBP3 TPd) and ADME toxicity of the isolated compounds was predicted. Results and Discussion. Angiopteroside (1) and osmundalactone (2) were isolated for the first time from the red rhizomes of A. helferiana. The structure of the isolated compounds was elucidated on the basis of spectroscopic (1H‐, 13C‐, and 13C/DEPT‐NMR) and spectrometric (LC MS/ESI and IR) analyses and comparison with reported literature. Both compounds were inactive towards DPPH scavenging activity. Compound 1 showed poor inhibitory activity against E. coli, with inhibition zone range of 2–7 mm. However, both isolated compounds were found to be resistant against S. aureus, K. pneumonia, and P. aeruginosa. Based on in silico molecular docking forecasting, compound 1 revealed the good binding affinity with PBP1b (−6.5 kcal/mol), PBP2 (−5.8 kcal/mol) and PBP3 TPd (−6.1 kcal/mol) compared to positive control meropenem with PBP1b (−6.6 kcal/mol), PBP2 (−6.9 kcal/mol), and PBP3 TPd (−6.6 kcal/mol). Similarly, compound 2 showed weak preference for PBP1b (−4.3 kcal/mol), PBP2 (−4.4 kcal/mol), and PBP TPd (−4.5 kcal/mol). Compounds 1 and 2 were predicted to be safe in terms of hepatotoxicity, cytotoxicity, mutagenicity, and carcinogenicity, with a potential to induce nephrotoxicity similar to that of meropenem. Conclusion. This study successfully isolates two lactones with antibacterial properties and inspires the researcher to further research, development, and formulation. [ABSTRACT FROM AUTHOR]

Background Klebsiella pneumoniae is capable of resistance to β-lactam antibiotics through expression of β-lactamases (both chromosomal and plasmid-encoded) and downregulation of outer membrane porins. However, the extent to which these mechanisms interplay in a resistant phenotype is not well understood. The purpose of this study was to determine the extent to which β-lactamases and outer membrane porins affected β-lactam resistance. Methods Minimum inhibitory concentrations (MICs) to β-lactams and inhibitor combinations were determined by agar dilution or Etest. Outer membrane porin production was evaluated by Western blot of outer membrane fractions. β-lactamase carriage was determined by whole genome sequencing and expression evaluated by real-time reverse-transcription polymerase chain reaction. Results Plasmid-encoded β--lactamases were important for cefotaxime and ceftazidime resistance. Elevated expression of chromosomal SHV was important for ceftolozane-tazobactam resistance. Loss of outer membrane porins was predictive of meropenem resistance. Extended-spectrum β-lactamases and plasmid-encoded AmpCs (pAmpCs) in addition to porin loss were sufficient to confer resistance to the third-generation cephalosporins, piperacillin-tazobactam, ceftolozane-tazobactam, and meropenem. pAmpCs (CMY-2 and DHA) alone conferred resistance to piperacillin-tazobactam. Conclusions Detection of a resistance gene by whole genome sequencing was not sufficient to predict resistance to all antibiotics tested. Some β-lactam resistance was dependent on the expression of both plasmid-encoded and chromosomal β-lactamases and loss of porins. [ABSTRACT FROM AUTHOR]

Bacterial biofilms, often forming on medical devices, can lead to treatment failure due to their increased antimicrobial resistance. Cefepime-avibactam (CFP-AVI) exhibits potent activities against Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) when used with polymyxin B (PMB). However, its efficacy in biofilm-related infections is unknown. The present study aimed to evaluate the activity of PMB combined with CFP-AVI against the biofilms of PMB-resistant Gram-negative bacteria. Five K. pneumoniae strains and three P. aeruginosa strains known to be PMB-resistant and prone to biofilm formation were selected and evaluated. Antimicrobial susceptibility assays demonstrated that the minimal biofilm inhibitory and eradication concentrations of PMB and CFP-AVI for biofilms formed by the eight strains were significantly higher than the minimal inhibitory concentrations of the antibiotics for planktonic cells. The biofilm formation inhibition and eradication assays showed that PMB combined with CFP-AVI cannot only suppress the formation of biofilm but also effectively eradicate the preformed mature biofilms. In a modified in vitro pharmacokinetic/pharmacodynamic biofilm model, CFP-AVI monotherapy exhibited a bacteriostatic or effective activity against the biofilms of seven strains, whereas PMB monotherapy did not have any activity at 72 h. However, PMB combined with CFP-AVI demonstrated bactericidal activity against the biofilms of all strains at 72 h. In an in vivo Galleria mellonella infection model, the 7-day survival rates of larvae infected with biofilm implants of K. pneumoniae or P. aeruginosa were 0-6.7%, 40.0-63.3%, and 46.7–90.0%, respectively, for PMB alone, CFP-AVI alone, and PMB combined with CFP-AVI; the combination therapy increased the rate by 6.7–33.3% (P < 0.05, n = 6), compared to CFP-AVI monotherapy. It is concluded that PMB combined with CFP-AVI exhibits effective anti-biofilm activities against PMB-resistant K. pneumoniae and P. aeruginosa both in vitro and in vivo, and thus may be a promising therapeutic strategy to treat biofilm-related infections. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae has been identified as one of the most important opportunistic pathogens responsible for nosocomial infections. Antibiotic resistance and the ability to form biofilms are the two main factors involved in the persistence of infections. Conventional detection methods involve culture isolation and identification followed by biofilm assay that takes 48–72 h. Timely detection of biofilm-forming resistant pathogens is essential to appropriately treat the infection with the right dose and combinations. The present study focuses on evaluating an RT-PCR panel using mrkD, pgaC, and wcaJ genes to screen for biofilm-forming K. pneumoniae from ETA/BAL specimens. The assay accurately identified K. pneumoniae harboring samples with a limit of detection of 1 ng/µl total RNA. Representative culture-negative-PCR-positive samples were subjected to metagenomics which identified K. pneumoniae reads in these samples confirming the specificity of RT-PCR. mrkD and pgaC act as K. pneumoniae specific identification whereas wcaJ acts as a negative marker for biofilm-forming K. pneumoniae. In addition, RT-PCR results correlated well with the phenotypic biofilm-forming assay. This RT-PCR assay is the first of its kind for rapid identification of biofilm-forming K. pneumoniae. The result of this study highlights that the rapid detection of K. pneumoniae biofilms based on the RT-PCR results coupled with clinical conditions would be appropriate to treat emerging infections or to prevent re-infections in clinical settings. [ABSTRACT FROM AUTHOR]

Arsenic contamination of soil and water is a major environmental issue. Bioremediation through plant growth-promoting bacteria is viable, cost-effective, and sustainable. Along with arsenic removal, it also improves plant productivity under stressful conditions. A crucial aspect of such a strategy is the selection of bacterial inoculum. The described study demonstrates that the indigenous wastewater isolate, ASBTKP1, could be a promising candidate. Identified as Klebsiella pneumoniae, ASBTKP1 harbors genes associated with heavy metal and oxidative stress resistance, production of antimicrobial compounds and growth-promotion activity. The isolate efficiently accumulated 30 µg/g bacterial dry mass of arsenic. Tolerance toward arsenate and arsenite was 120 mM and 70 mM, respectively. Plant biomass content of Vigna radiata improved by 13% when grown in arsenic-free soil under laboratory conditions in the presence of the isolate. The increase became even more significant under the same conditions in the presence of arsenic, recording a 37% increase. The phylogenetic analysis assigned ASBT-KP1 to the clade of Klebsiella strains that promote plant growth. Similar results were also observed in Oryza sativa, employed to assess the ability of the strain to promote growth, in plants other than V. radiata. This study identifies a prospective candidate in ASBT-KP1 that could be employed as a plant growth-promoting rhizoinoculant in agricultural practices. [ABSTRACT FROM AUTHOR]

Introduction: The rising prevalence of Extended-Spectrum Beta-Lactamase (ESBL)-producing Klebsiella species (spp.) poses a significant threat to human and animal health and environmental safety. To address this pressing issue, a comprehensive study was undertaken to elucidate the burden and dissemination mechanisms of ESBL-Klebsiella spp. in dairy cattle farms. Methods: Fifty-seven Klebsiella species were isolated on CHROMagarTM ESBL plates and confirmed with MADLI-TOF MS and whole genome sequenced from 14 dairy farms. Results and discussion: Six families of beta-lactamase (bla) (blaCTX·M, blaSHV, blaTEM, blaOXY, blaOXA; and blaSED) were detected in ESBL-Klebsiella spp. genomes. Most (73%) of isolates had the first three types of beta-lactamase genes, with blaSHV being the most frequent, followed by blaCTX·M. Most (93%) isolates harbored two or more bla genes. The isolates were genotypically MDR, with 26 distinct types of antibiotic resistance genes (ARGs) and point mutations in gyrA, gyrB, and parC genes. The genomes also harbored 22 different plasmid replicon types, including three novel IncFII. The IncFII and Col440I plasmids were the most frequent and were associated with blaCTXM-27 and qnrB19 genes, respectively. Eighteen distinct sequence types (STs), including eight isolates with novel STs of K. pneumoniae, were detected. The most frequently occurring STs were ST353 (n = 8), ST469 (n = 6), and the novel ST7501 (n = 6). Clusters of ESBL-Klebsiella strains with identical STs, plasmids, and ARGs were detected in multiple farms, suggesting possible clonal expansion. The same ESBL variant was linked to identical plasmids in different Klebsiella STs in some farms, suggesting horizontal spread of the resistance gene. The high burden and dual spread mechanism of ESBL genes in Klebsiella species, combined with the emergence of novel sequence types, could swiftly increase the prevalence of ESBL-Klebsiella spp., posing significant risks to human, animal, and environmental health. Immediate action is needed to implement rigorous surveillance and control measures to mitigate this risk. [ABSTRACT FROM AUTHOR]

Carbapenem resistant Klebsiella pneumoniae causing severe infection resulting in morbidity and mortality have become a global health concern. K. pneumoniae with sequence type ST147 is an international high-risk clonal lineage, genomic studies have been done on K. pneumoniae ST147 isolated from clinical origin but genomic data for environmental K. pneumoniae ST147 is very scarce. Herein, K. pneumoniae IITR008, an extensively drug resistant and potentially hypervirulent bacterium, was isolated from Triveni Sangam, the confluence of three rivers where religious congregations are organized. Phenotypic, genomic and comparative genomic analysis of strain IITR008 was performed. Antibiotic susceptibility profiling revealed resistance to 9 different classes of antibiotics including ß-lactams, ß-lactam combination agents, carbapenem, aminoglycoside, macrolide, quinolones, cephams, phenicol, and folate pathway antagonists and was found to be susceptible to only tetracycline. The strain IITR008 possesses hypervirulence genes namely, iutA and iroN in addition to numerous virulence factors coding for adherence, regulation, iron uptake, secretion system and toxin. Both the IITR008 chromosome and plasmid pIITR008_75 possess a plethora of clinically relevant antibiotic-resistant genes (ARGs) including blaCTX-M-15, blaTEM-1, and blaSHV-11, corroborating the phenotypic resistance. Comparative genomic analysis with other ST147 K. pneumoniae provided insights on the phylogenetic clustering of IITR008 with a clinical strain isolated from a patient in Czech with recent travel history in India and other clinical strains isolated from India and Pakistan. According to the 'One Health' perspective, surveillance of antibiotic resistance in the environment is crucial to impede its accelerated development in diverse ecological niches. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to evaluate the prevalence of Klebsiella pneumoniae contamination in raw lettuce from Risalpur, Pakistan, and to analyze the antibiotic susceptibility profiles of the isolated strains. The presence of foodborne pathogens such as K. pneumoniae poses significant public health risks, particularly in regions with suboptimal hygiene practices and improper food handling. Methods: Lettuce samples were collected from various sources in Risalpur and screened for K. pneumoniae. Antimicrobial susceptibility testing was performed to evaluate the effectiveness of various antibiotics against the isolated strains. Statistical analyses, including ANOVA and linear regression, were conducted to assess differences in inhibition zones and to predict antibiotic effectiveness based on concentration. Results: The results revealed a significant prevalence of K. pneumoniae in the lettuce samples, highlighting the risks associated with poor hygiene, transportation, storage, and contaminated irrigation water. The isolated strains exhibited high susceptibility to gentamicin but demonstrated notable resistance to doxycycline, vancomycin, and ticarcillin. Multidrug-resistant (MDR) strains were identified. ANOVA showed significant differences in inhibition zones, and the linear regression model predicted a Zone of Inhibition based on antibiotic concentration (β0 = 10.6667, β1 = 0.4556). Discussion: The identification of MDR strains of K. pneumoniae underscores the urgent need for enhanced antibiotic stewardship and food safety protocols to manage foodborne pathogens. Improved hygiene practices throughout the food production and supply chain are critical to mitigate health risks and address the challenge of growing antibiotic resistance. [ABSTRACT FROM AUTHOR]

Background: The dissemination of Klebsiella spp. producing multiple carbapenemases has been increasingly recognized. Between July 2019 and August 2021, ten patients were found to carry Klebsiella spp. co-harboring blaKPC−4 and blaVIM−1 across multiple wards at a Korean hospital, and one isolate was recovered from a hand-washing sink, more than a year after the outbreak. This study aimed to investigate the outbreak and conduct a genomic study of these isolates. Methods: Whole-genome sequencing, including long-read sequencing, was performed to analyze plasmid structures and mobile genetic elements (MGEs). Bioinformatics analyses were performed to trace clonal transmission chains and horizontal gene transfer. Results: The findings suggested that the inter-ward spread of Klebsiella spp. seemed to be facilitated by healthcare worker contact or patient movement. Of the nine isolates collected (eight clinical and one environmental), seven (including the environmental isolate) were identified as K. pneumoniae (ST3680) and two were K. variicola (single-locus variant of ST5252). These isolates showed high genetic relatedness within their species and harbored the IncHI5B plasmid carrying both blaKPC−4 and blaVIM−1 (pKPCVIM.1). On this plasmid, blaVIM−1 was located in the Class 1 integron associated with IS1326::IS1353 (In2), and Tn4401b carrying blaKPC−4 was inserted into IS1326::IS1353, creating a novel MGE construct (In2_blaVIM−1-Tn4401b_blaKPC−4). Conclusion: The hospital-wide spread of blaKPC−4 and blaVIM−1 was facilitated by clonal spread and horizontal plasmid transfer. The persistence of this strain in the hospital sink suggests a potential reservoir of the strain. Understanding the transmission mechanisms of persistent pathogens is important for improving infection control strategies in hospitals. [ABSTRACT FROM AUTHOR]

Background: Carbapenem-resistant and hypervirulent Klebsiella pneumoniae (CR-hvKP) caused infections of high mortality and brought a serious impact on public health. This study aims to evaluate the epidemiology, resistance and virulence characteristics of CR-hvKP and to identify potential drivers of cross-regional transmission in different regions of China, in order to provide a basis for developing targeted prevention measures. Methods: Clinical K. pneumoniae strains were collected from Jiujiang and Nanchang in Jiangxi province between November 2021 to June 2022. Clinical data of patients (age, sex, source of infection, and diagnosis) were also gathered. We characterized these strains for their genetic relatedness using PFGE, antimicrobial and virulence plasmid structures using whole-genome sequencing, and toxicity using Galleria mellonella infection model. Results: Among 609 strains, 45 (7.4%) CR-hvKP were identified, while the strains. isolated from Nanchang and Jiujiang accounted for 10.05% (36/358) and 3.59% (9/251). We observed that ST11-KL64 CR-hvKP had an overwhelming epidemic dominance in these two regions. Significant genetic diversity was identified among all ST11-KL64 CR-hvKP cross-regional transmission between Nanchang and Jiujiang and this diversity served as the primary driver of the dissemination of clonal groups. Virulence genes profile revealed that ST11-KL64 CR-hvKP might harbour incomplete pLVPK-like plasmids and primarily evolved from CRKP by acquiring the hypervirulence plasmid. We found the predominance of truncated-IncFIB/IncHI1B type virulence plasmids with a 25 kb fragment deletion that encoded iroBCDN clusters. Conclusion: ST11-KL64 is the most cross-regional prevalent type CR-hvKPs in Jiangxi province, which mainly evolved from CRKPs by acquiring a truncated-IncHI1B/IncFIB virulence plasmid with the deletion of iroBCDN. Stricter surveillance and control measures are urgently needed to prevent the epidemic transmission of ST11-KL64 CR-hvKP. [ABSTRACT FROM AUTHOR]

Background: The co-occurrence of Lemierre's syndrome, primarily triggered by Fusobacterium necrophorum following oropharyngeal infection, with diabetic ketoacidosis (DKA) in diabetes mellitus (DM) patients, underscores a rare but life-threatening clinical scenario. Lemierre's syndrome induced DKA is extremely rare, with only one case report in adult and no case yet reported in elderly. Case Presentation: We reported a case of a 69-year-old female who presented with DKA triggered by deep neck space infection (DNSI), leading to rapid clinical deterioration within 6 h that necessitated high flow nasal cannula (HFNC) and antibiotic administration. Laboratory findings included leukocytosis, elevated serum C-reactive protein, hyperglycemia, ketonemia, and severe metabolic acidosis. Culture of the fluid from a neck mass puncture drainage and blood were positive for Klebsiella pneumoniae. The patient was further complicated by thrombosis of the left internal jugular vein with extension to the sigmoid and a neck abscess surrounding the carotid artery sheath, consistent with Lemierre's syndrome. This condition was managed aggressively with fluid resuscitation, insulin therapy, surgical drainage, antibiotics, and anticoagulation led to a significant improvement in her condition. Following a 13-day hospitalization, there was significant clinical improvement, culminating in the patient's discharge. Conclusions: The case highlights the need for greater awareness and understanding of the interrelated and mutually promoting conditions of DKA and Lemierre's syndrome among clinicians. Early recognition and treatment are crucial to prevent mortality in such complex cases. [ABSTRACT FROM AUTHOR]

Lemierre's syndrome, a forgotten clinical entity, is characterised by septic thrombophlebitis of the internal jugular vein due to oropharyngeal infection. In the past, it was mainly associated with Fusobacterium necrophorum infections. We present a unique case report of Lemierre's syndrome due to Klebsiella pneumoniae. Patient reported with progressive swelling involving right side of the neck that eventually increased in size. After confirming the diagnosis through CECT, patient was managed through combined medical and surgical therapy in the form of incision and drainage, targeted antibiotic therapy, glycaemic control and anticoagulation therapy. This case report highlights the association of poor glycaemic control in the pathogenesis and the isolation of Klebsiella pneumoniae as the rare organism of Lemierre's syndrome. [ABSTRACT FROM AUTHOR]

Introduction: The rising prevalence of Extended-Spectrum Beta-Lactamase (ESBL)-producing Klebsiella species (spp.) poses a significant threat to human and animal health and environmental safety. To address this pressing issue, a comprehensive study was undertaken to elucidate the burden and dissemination mechanisms of ESBL-Klebsiella spp. in dairy cattle farms. Methods: Fifty-seven Klebsiella species were isolated on CHROMagar™ ESBL plates and confirmed with MADLI-TOF MS and whole genome sequenced from 14 dairy farms. Results and discussion: Six families of beta-lactamase (bla) (blaCTX-M, blaSHV, blaTEM, blaOXY, blaOXA, and blaSED) were detected in ESBL-Klebsiella spp. genomes. Most (73%) of isolates had the first three types of beta-lactamase genes, with blashy being the most frequent, followed by blaCTX-M. Most (93%) isolates harbored two or more bla genes. The isolates were genotypically MDR, with 26 distinct types of antibiotic resistance genes (ARGs) and point mutations in gyrA, gyrB, and parC genes. The genomes also harbored 22 different plasmid replicon types, including three novel IncFII. The IncFIl and Col4401 plasmids were the most frequent and were associated with blaCTXM-27 and qnrB19 genes, respectively. Eighteen distinct sequence types (STs), including eight isolates with novel STs of K. pneumoniae, were detected. The most frequently occurring STs were ST353 (n = 8), ST469 (n = 6), and the novel ST7501 (n = 6). Clusters of ESBL-Klebsiella strains with identical STs, plasmids, and ARGs were detected in multiple farms, suggesting possible clonal expansion. The same ESBL variant was linked to identical plasmids in different Klebsiella STs in some farms, suggesting horizontal spread of the resistance gene. The high burden and dual spread mechanism of ESBL genes in Klebsiella species, combined with the emergence of novel sequence types, could swiftly increase the prevalence of ESBL-Klebsiella spp., posing significant risks to human, animal, and environmental health. Immediate action is needed to implement rigorous surveillance and control measures to mitigate this risk. [ABSTRACT FROM AUTHOR]

Arsenic contamination of soil and water is a major environmental issue. Bioremediation through plant growth-promoting bacteria is viable, cost-effective, and sustainable. Along with arsenic removal, it also improves plant productivity under stressful conditions. A crucial aspect of such a strategy is the selection of bacterial inoculum. The described study demonstrates that the indigenous wastewater isolate, ASBTKP1, could be a promising candidate. Identified as Klebsiella pneumoniae, ASBTKP1 harbors genes associated with heavy metal and oxidative stress resistance, production of antimicrobial compounds and growth-promotion activity. The isolate efficiently accumulated 30 μg/g bacterial dry mass of arsenic. Tolerance toward arsenate and arsenite was 120 mM and 70 mM, respectively. Plant biomass content of Vigna radiata improved by 13% when grown in arsenic-free soil under laboratory conditions in the presence of the isolate. The increase became even more significant under the same conditions in the presence of arsenic, recording a 37% increase. The phylogenetic analysis assigned ASBT-KP1 to the clade of Klebsiella strains that promote plant growth. Similar results were also observed in Oryza sativa, employed to assess the ability of the strain to promote growth, in plants other than V. radiata. This study identifies a prospective candidate in ASBT-KP1 that could be employed as a plant growth-promoting rhizoinoculant in agricultural practices. [ABSTRACT FROM AUTHOR]

Background: Pediatric patients are vulnerable to the threat of carbapenem-resistant Klebsiella pneumoniae (CRKP) due to their limited immunity and few available antibiotics. Especially when these pathogens exhibit hypervirulent phenotypes, they are often associated with poor clinical outcomes. Methods: In this study, we investigated a CRKP outbreak in pediatric patients from 2019 to 2021 in a teaching hospital in China based on whole genome sequencing. We sequenced twenty-nine CRKP isolates isolated from unduplicated pediatric patients to understand their genetic relationships, virulence factors, resistance mechanisms, and transmission trajectories. Conjugation experiments were performed to evaluate the horizontal transfer ability of carbapenem resistance determinants in twenty-nine CRKP isolates. We then characterized these isolates for biofilm formation ability and serum resistance. Genetic relatedness, comparison of plasmids, and chromosomal locus variation of CRKP isolates were analyzed by bioinformatics. Results: All the isolates were carbapenemase-producers harbouring blaNDM−5. Among them, twenty-eight isolates belonged to the ST2407 group, with the consistent capsular serotype K25. The virulence-related factors: ureA, fim, ybtA, irp1/irp2, and mrkA were prevalent in these isolates. Additionally, most CRKP isolates showed moderately adherent biofilm formation. Although the ST2407 clonal group did not exhibit serum resistance, the heterogeneous level of serum resistance was related to the disruption of oqxR. Conjugation and WGS revealed that the blaNDM−5 carried by the twenty-eight CRKP ST2407 isolates was located on nonconjugative IncX3 plasmids associated with deleting the T4SS-encoding genes. Clonal transmission of CRKP ST2407 in pediatric patients was suggested by the phylogenetic tree. Conclusions: Our study provides evidence of the clonal spread of blaNDM−5-producing K. pneumoniae in pediatric patients and the necessity for the T4SS system for horizontal transfer of the IncX3 plasmid carrying blaNDM−5. Additionally, the disruption of oqxR may have affected the serum resistance of CRKP. The results of this study emphasize the importance of continuously monitoring for CRKP infection in pediatric patients to prevent recurrent infections. [ABSTRACT FROM AUTHOR]

Introduction: Gram-negative bacteremia is a life-threatening infection with high morbidity and mortality. Its incidence is rising worldwide, and treatment has become more challenging due to emerging bacterial resistance. Little data is available on the burden and outcome of such infections in Lebanon. Methods: We conducted this retrospective study in four Lebanese hospitals. Data on medical conditions and demographics of 2400 patients diagnosed with a bloodstream infection based on a positive blood culture were collected between January 2014 and December 2020. Results: Most bacteremias were caused by Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii, with the more resistant organisms being hospital-acquired. Third-generation cephalosporin and quinolone resistance was steady throughout the study, but carbapenem resistance increased. Mortality with such infections is high, but carbapenem resistance or infection with Pseudomonas or Acinetobacter species were significant risk factors for poor outcomes. Conclusion: This is the first multi-center study from Lebanon on gram-negative bacteremia, resistance patterns, and factors associated with a poor outcome. More surveillance is needed to provide data to guide empirical treatment for bacteremia in Lebanon. [ABSTRACT FROM AUTHOR]

Background: This study aims to investigate the frequency of cas1 and cas3 and CRISPR1,2,3 genes in Klebsiella pneumoniae isolates, as well as their connection with antibiotic resistance. Materials and methods: 106 K. pneumoniae isolates were identified by biochemical assays and PCR. The susceptibility to antibiotics was determined by Kirby–Bauer disk diffusion method. Screening of ESBLs was undertaken by using double disk diffusion and standard disk diffusion methods. The E-test and mCIM techniques was used to confirm the disc diffusion-based carbapenem resistance profiles. CRISPR-Cas system genes were identified using PCR. Results: ESBL production was found in 19% of isolates. Carbapenemase production was found in 46% of the isolates. Furthermore, the bacteria were classified as multidrug (76%), extensively drug-resistant (4%), or pan-drug-resistant (2%). When CRISPR/Cas systems were present, antibiotic resistance was lower; conversely, when they were absent, resistance was higher. Conclusions: If the CRISPR/Cas modules aren't present, the bacteria can still acquire foreign DNA, including antibiotic resistance genes. K. pneumoniae isolates with a CRISPR-Cas system were less likely to carry antibiotic-resistance genes than those lacking this defense system. [ABSTRACT FROM AUTHOR]

Livestock manure treatment technology and composting and its products have been widely used in agricultural soil. However, little was known about the variations in the fate of pathogens and the factors affecting their pathogenic ability during this process, which posed threats to ecological safety and public health globally. This study used a metagenomic approach to profile the behaviors of pathogens during peroxydisulfate composting. Results showed that Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Burkholderia pseudomallei, and Mycobacterium tuberculosis were the main secretors of virulence factors (VFs) in composting system; their abundance and the virulence factor–related genes they carried were better downregulated under the role of peroxydisulfate. In addition, peroxydisulfate composting ensured the lower moisture, weakening the swimming mobility behavior of pathogens through suppressing the abundance of genes associated with flagellar formation, and impaired the communication between pathogens by regulating quorum sensing (QS)– and quorum quenching (QQ)–related genes. Moreover, reduced abundance of resistomes restricted pathogens disseminating infection. In summary, this study provided useful strategies in managing pathogen pathogenic ability during composting based on pathogenic source (pathogens), pathway (VFs), influencing factors (QS/QQ, physicochemical habitats), and resistomes. [ABSTRACT FROM AUTHOR]

Lytic bacteriophages (phages) are promising clinically viable therapeutic options against carbapenem-resistant Klebsiella pneumoniae (CRKP). In China, the predominant strains are those assigned to sequence type 11 and capsular type 64 (ST11-KL64). The emergence of phage resistance is a major bottleneck hindering effective phage therapy, requiring more new phages to provide the flexibility for creating different phage cocktails. However, the majority of phages against ST11-KL64 CRKP belong to the genus Przondovirus of the family Autographiviridae, which limits the options for constructing cocktails. We recovered a novel lytic phage of the genus Taipeivirus within the family Ackermannviridae against ST11-KL64 CRKP from a river in China. We phenotypically characterized this phage and obtained its genome sequence for analysis. This phage can inhibit the growth of ST11-KL64 CRKP for 6.5 h at a 0.1 multiplicity of infection and exhibits a narrow host range, being unable to attack CRKP strains of the other 30 capsular types. This phage carries no genes encoding antimicrobial resistance, virulence, or lysogeny. It is stable across a wide range of temperatures and pH values, making it suitable for phage therapy. Unlike other Taipeivirus phages, P01 has two tail spike proteins and a unique tail fiber protein. The distinct tail composition of this phage contributes to its activity against ST11-KL64 CRKP and its narrow host range. Taken together, we recovered a phage of a novel viral species with the potential for therapy, which expands the phage biobank against CRKP. [ABSTRACT FROM AUTHOR]

Traditional antibiotics have been effective in many cases. However, the rise in multidrug-resistant bacteria has diminished their therapeutic efficacy, signaling the dawn of an era beyond antibiotics. The challenge of multidrug resistance in Klebsiella pneumoniae is particularly critical, with increasing global mortality and resistance rates. Therefore, the development of alternative therapies to antibiotics is urgently needed. Phages, which are natural predators of bacteria, have inherent advantages. However, comprehensive information on K. pneumoniae phages is lacking in current literature. This review aims to analyze and summarize relevant studies, focusing on the present state of phage therapy for K. pneumoniae infections. This includes an examination of treatment methodologies, associated challenges, strategies, new phage technologies, clinical trial safety and efficacy, regulatory issues, and future directions for phage therapy development. Enhancing phage technology is crucial for addressing the evolving threat of multidrug-resistant K. pneumoniae. [ABSTRACT FROM AUTHOR]

Objectives Pharmacodynamic parameters evaluated under conditions that simulate an infection site volume and microbial load might reveal hidden risks of resistance selection and subsequent treatment failure. The study aimed to investigate the predictive potential of MICs determined at various conditions on the antimicrobial effect and emergence of resistance. Methods We assessed meropenem MICs (microdilution: 0.2 mL, 5 × 105 cfu/mL; macrodilution: 2 mL, 5 × 105 cfu/mL), MICHVs (220 mL, 5 × 105 cfu/mL), MICHIs (0.2 mL, 5 × 107 cfu/mL) and MICHVIs (220 mL, 5 × 107 cfu/mL) for five Klebsiella pneumoniae strains and analysed these values alongside the results of experiments in a dynamic in vitro model. A clinically relevant meropenem dosing regimen was simulated and the starting bacterial inocula were 106 and 108 cfu/mL. Results The effectiveness of meropenem agreed with MICHVs for the 106 cfu/mL inoculum and with MICHIs or MICHVIs for the 108 cfu/mL inoculum. Strains characterized as resistant according to these values grew during meropenem exposure, and resistant mutants were selected. Conclusions Our results suggest that MICHV-based parameters may be suitable for predicting antibacterial effects and the risk of resistance development when the inoculum is 106 cfu/mL, while MICHI- or MICHVI-based parameters are suitable for these purposes when the inoculum is 108 cfu/mL. Also, the correlation between resistance selection and the MICHI-based parameter was as high as one that corresponds with a mutant prevention concentration (MPC)-based parameter; this suggests that the MPC can be replaced by the more easily determined alternative parameter MICHI. [ABSTRACT FROM AUTHOR]

In Enterobacteriaceae, susceptibility to cephalosporins and carbapenems is often associated with membrane and enzymatic barrier resistance. For about 20 years, a large number of Klebsiella pneumoniae , Escherichia coli and Enterobacter cloacae presenting ß-lactam resistance have been isolated from medical clinics. In addition, some of the resistant isolates exhibited alterations in the outer membrane porin OmpC-OmpF orthologues, resulting in the complete absence of gene expression, replacement by another porin or mutations affecting channel properties. Interestingly, for mutations reported in OmpC-OmpF orthologues, major changes in pore function were found to be present in the gene encoding for OmpC. The alterations were located in the constriction region of the porin and the resulting amino acid substitutions were found to induce severe restriction of the lumen diameter and/or alteration of the electrostatic field that governs the diffusion of charged molecules. This functional adaptation through porins maintains the entry of solutes necessary for bacterial growth but critically controls the influx of harmful molecules such as β-lactams at a reduced cost. The data recently published show the importance of understanding the underlying parameters affecting the uptake of antibiotics by infectious bacteria. Furthermore, the development of reliable methods to measure the concentration of antibiotics within bacterial cells is key to combat impermeability-resistance mechanisms. [ABSTRACT FROM AUTHOR]

Objective To analyse the biliary pharmacokinetics/pharmacodynamics (PK/PD) of continuous infusion (CI) meropenem-vaborbactam (MEM-VBM) in a case series of orthotopic liver transplant (OLT) recipients being treated for Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) related biliary tract infections (BTIs) or as preemptive therapy of KPC-Kp rectal colonization. Methods Critical OLT recipients receiving CI MEM-VBM (2 g/2 g q8h over 8 h) because of KPC-Kp related BTIs or as preemptive therapy of KPC-Kp rectal colonization, having Kehr's tube positioned and undergoing simultaneous therapeutic drug monitoring of MEM and VBM in plasma and bile were retrospectively assessed. Bile-to-plasma ratio of free steady-state concentrations (f Css) of MEM and VBM was used for assessing biliary penetration. Optimal joint MEM-VBM PK/PD target attainment was defined as MEM f Css/MIC ratio >4 coupled with VBM free area under time–concentration curve (f AUC)/threshold concentration (CT) ratio >24. Results Overall, four critical OLT recipients were included. Median bile-to-plasma ratio was 0.32 for MEM (range 0.21–0.79) and 0.40 for VBM (range 0.20–0.77). Biliary MEM-VBM joint PK/PD target attainment was optimal in 3/4 OLT recipients and quasi-optimal in the other one. Conclusions The 1:1 proportion between MEM and VBM concentrations was maintained unchanged in the bile, allowing us to assume that the efficacy of MEM-VBM may be appropriate even in the treatment of BTIs. CI administration was an effective strategy for attaining aggressive biliary joint PK/PD targets against pathogens with an MIC up to 2 mg/L. [ABSTRACT FROM AUTHOR]

Treatment of patients with serious infections due to resistant Gram-negative bacteria remains highly problematic and has prompted clinicians to use existing antimicrobial agents in innovative ways. One approach gaining increased therapeutic use is combination therapy with IV fosfomycin. This article reviews the preclinical pharmacokinetic / pharmacodynamic (PK/PD) infection model and clinical data surrounding the use of combination therapy with IV fosfomycin for the treatment of serious infections caused by resistant Gram-negative bacteria. Data from dynamic in vitro and animal infection model studies of highly resistant Enterobacterales and non–lactose fermenters are positive and suggest IV fosfomycin in combination with a β-lactam, polymyxin or aminoglycoside produces a synergistic effect that rivals or surpasses that of other aminoglycoside- or polymyxin-containing regimens. Clinical studies performed to date primarily have involved patients with pneumonia and/or bacteraemia due to Klebsiella pneumoniae , Pseudomonas aeruginosa or Acinetobacter baumannii. Overall, the observed success rates with fosfomycin combination regimens were consistent with those reported for other combination regimens commonly used to treat these patients. In studies in which direct treatment comparisons can be derived, the results suggest that patients who received fosfomycin combination therapy had similar or improved outcomes compared with other therapies and combinations, especially when it was used in combination with a β-lactam that (1) targets PBP-3 and (2) has exceptional stability in the presence of β-lactamases. Collectively, the data indicate that combination therapy with IV fosfomycin should be considered as a potential alternative to aminoglycoside or polymyxin combinations for patients with antibiotic-resistant Gram-negative infections when benefits outweigh risks. [ABSTRACT FROM AUTHOR]

Objectives Klebsiella pneumoniae is a significant pathogen with increasing resistance and high mortality rates. Conventional antibiotic susceptibility testing methods are time-consuming. Next-generation sequencing has shown promise for predicting antimicrobial resistance (AMR). This study aims to develop prediction models using whole-genome sequencing data and assess their feasibility with metagenomic next-generation sequencing data from clinical samples. Methods On the basis of 4170 K. pneumoniae genomes, the main genetic characteristics associated with AMR were identified using a LASSO regression model. Consequently, the prediction model was established, validated and optimized using clinical isolate read simulation sequences. To evaluate the efficacy of the model, clinical specimens were collected. Results Four predictive models for amikacin, ciprofloxacin, levofloxacin, and piperacillin/tazobactam, initially had positive predictive values (PPVs) of 92%, 98%, 99%, 94%, respectively, when they were originally constructed. When applied to clinical specimens, their PPVs were 96%, 96%, 95%, and 100%, respectively. Meanwhile, there were negative predictive values (NPVs) of 100% for ciprofloxacin and levofloxacin, and 'not applicable' (NA) for amikacin and piperacillin/tazobactam. Our method achieved antibacterial phenotype classification accuracy rates of 95.92% for amikacin, 96.15% for ciprofloxacin, 95.31% for levofloxacin and 100% for piperacillin/tazobactam. The sequence-based prediction antibiotic susceptibility testing (AST) reported results in an average time of 19.5 h, compared with the 67.9 h needed for culture-based AST, resulting in a significant reduction of 48.4 h. Conclusions These preliminary results demonstrated that the performance of prediction model for a clinically significant antimicrobial–species pair was comparable to that of phenotypic methods, thereby encouraging the expansion of sequence-based susceptibility prediction and its clinical validation and application. [ABSTRACT FROM AUTHOR]

Organic compounds with antibacterial and antiparasitic properties are gaining significance for biomedical applications. This study focuses on the solvent-free synthesis (green synthesis) of 1,4-naphthoquinone or 2,3-dichloro-1,4-naphthoquinone with different phenylamines using silica gel as an acid solid support. The study also includes in silico PASS predictions and the discovery of antibacterial and antiparasitic properties of phenylaminonaphthoquinone derivatives 1–12, which can be further applied in drug discovery and development. These activities were discussed in terms of molecular descriptors such as hydrophobicity, molar refractivity, and half-wave potentials. The in vitro antimicrobial potential of the synthesized compounds 1–12 was evaluated against a panel of six bacterial strains (three Gram-positive: Staphylococcus aureus, Proteus mirabilis, and Enterococcus faecalis; and three Gram-negative bacteria: Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae). Six compounds (1, 3, 5, 7, 10, and 11) showed better activity toward S. aureus with MIC values between 3.2 and 5.7 μg/mL compared to cefazolin (MIC = 4.2 μg/mL) and cefotaxime (MIC = 8.9 μg/mL), two cephalosporin antibiotics. Regarding in vitro antiplasmodial activity, compounds 1 and 3 were the most active against the Plasmodium falciparum strain 3D7 (chloroquine-sensitive), displaying IC50 values of 0.16 and 0.0049 μg/mL, respectively, compared to chloroquine (0.33 μg/mL). In strain FCR-3 (chloroquine-resistant), most of the compounds showed good activity, with compounds 3 (0.12 μg/mL) and 11 (0.55 μg/mL) being particularly noteworthy. Additionally, docking studies were used to better rationalize the action and prediction of the binding modes of these compounds. Finally, absorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions were performed. [ABSTRACT FROM AUTHOR]