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The association between the COVID-19 pandemic and the incidence of invasive infections caused by multidrug-resistant organisms remains a topic of debate. To analyse the national incidence rates of bloodstream infections (BSI) caused by Escherichia coli (EC) and Klebsiella pneumoniae (KP) with extended-spectrum cephalosporin resistance (ESCR) in two distinct regions in Switzerland, each exhibiting varying antimicrobial resistance patterns and that were impacted differently by the pandemic. Data was analysed from positive blood cultures prospectively collected by the nationwide surveillance system (ANRESIS) from January 1st, 2015, to August 31st, 2022. To explore the potential relationship between COVID-19 patient occupancy and ESCR incidence rates, an in-depth analysis was conducted over the two-year pandemic period from April 1st, 2020, to March 30th, 2022, using Quasi-Poisson and logistic regression analyses. During the study period, 40,997 EC-BSI and 8537 KP-BSI episodes were collected and reported to ANRESIS by the participating hospitals. ESCR was observed in 11% (N = 4313) of E. coli and 8% (N = 664) of K. pneumoniae , respectively. A significant reduction in ESCR-EC BSI incidence occurred during the pandemic in the region with the highest COVID-19 incidence. Conversely, ESCR-KP BSI incidence initially fell considerably and then increased during the pandemic in both regions, though this effect was not statistically significant. No association between hospital occupancy from COVID-19 patients and these trends was observed. In the early phase of the COVID-19 pandemic, a decrease in ESCR rates was observed, particularly in ESCR-EC BSI within the most heavily impacted region. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae (KP) is an opportunistic pathogen causing severe pneumonia and sepsis. Carbapenem-resistant KP (CRKP) has become a major pathogen in many centres. To investigate the association between carbapenem resistance and the mortality rate, length of stay, and hospital cost in patients with Klebsiella pneumoniae infection. The retrospective cohort study was conducted in the intensive care units of a large teaching tertiary hospital in southwest China between January 1st, 2020 and December 31st, 2022. To examine the impact of carbapenem resistance on mortality rates and economic burden, multivariate Cox regression and generalized linear models were constructed. The study included 282 adult patients with KP infection (135 CSKP; 147 CRKP). CRKP-infected patients demonstrated higher mortality risk (unadjusted hazard ratio (aHR): 1.980; 95% confidence interval (CI): 1.206–3.248; P = 0.007; aHR: 1.767; 95% CI: 1.038–3.005; P = 0.036) compared to CSKP-infected patients. Stratified analysis, according to type of KP infection, revealed that patients with healthcare-associated CRKP infection had a significantly higher mortality risk compared to those with CSKP infection (log-rank P = 0.015). Patients with CRKP infection had longer hospital stays than those infected with CSKP (adjusted mean: 38.74 vs 29.71 days; P = 0.003), and hospital-related expenses were notably higher among CRKP patients than CSKP patients (adjusted cost: £40,126.73 vs 25,713.74; P < 0.001). CRKP infections increase mortality rates, prolong hospital stays, and raise healthcare costs. Healthcare facilities should adopt targeted strategies, including curtailing pre-infection hospitalization periods and managing medications more judiciously. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae has become one of the most intractable gram-negative pathogens infecting humans and animals due to its severe antibiotic resistance. Bacteriophages and protein products derived from them are receiving increasing amounts of attention as potential alternatives to antibiotics. In this study, we isolated and investigated the characteristics of a new lytic phage, P1011, which lyses K5 K. pneumoniae specifically among 26 serotypes. The K5-specific capsular polysaccharide-degrading depolymerase dep1011 was identified and expressed. By establishing murine infection models using bovine strain B16 (capable of supporting phage proliferation) and human strain KP181 (incapable of sustaining phage expansion), we explored the safety and efficacy of phage and dep1011 treatments against K5 K. pneumoniae. Phage P1011 resulted in a 60% survival rate of the mice challenged with K. pneumoniae supporting phage multiplication, concurrently lowering the bacterial burden in their blood, liver, and lungs. Unexpectedly, even when confronted with bacteria impervious to phage multiplication, phage therapy markedly decreased the number of viable organisms. The protective efficacy of the depolymerase was significantly better than that of the phage. The depolymerase achieved 100% survival in both treatment groups regardless of phage propagation compatibility. These findings indicated that P1011 and dep1011 might be used as potential antibacterial agents to control K5 K. pneumoniae infection. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is an emerging problem worldwide, endangering antimicrobials efficacy and resulting in high rates of morbidity and mortality. It is one of the major concerns that health care facilities are facing nowadays. Mainly, extended-spectrum beta-lactamases (ESBL)-producing Enterobacterales play a role in hydrolyzing β-lactams, specifically the third-generation cephalosporins. This study aimed to investigate the prevalence of fecal carriage and molecular characterization of ESBL-producing Enterobacterales among Lebanese elderly residents in a long-term care facility (Dar Al-Ajaza Al Islamia Hospital). Rectal culture swab specimens were collected from 132 patients at Dar Al Ajaza Al Islamia hospital between January 2019 till June 2020. The phenotype of ESBL producers was confirmed by a modified double disc synergy test and antibiotic susceptibility was determined using the Kirby-Bauer disk diffusion method. Genotypically, multiplex polymerase chain reaction was used to detect the ESBL genes. The main Enterobacterales strain observed was E coli (90.15%) followed by Klebsiella pneumoniae (4.54%) and Klebsiella oxytoca (3.80%). It has been found that the ESBL percentage rate has decreased when compared to a study conducted previously at the same hospital. Moreover, the predominant ESBL gene was CTX-M (cefotaximase). This study is the first to demonstrate the improved current status of ESBL in one long-term care facility. In addition, the CTX-M is still the major type in ESBL-producing organisms. • Antimicrobial resistance is an emerging problem worldwide. • The main Enterobacterales strain observed was E coli followed by Klebsiella. • ESBL-PE percentage rate has decreased when compared to a study conducted previously. • The predominant ESBL gene was CTX-M. [ABSTRACT FROM AUTHOR]

Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a substantial healthcare challenge. This study assessed the in vitro efficacy of selected antibiotic combinations against CRKP infections. Our research involved the evaluation of 40 clinical isolates of CRKP, with half expressing Klebsiella pneumoniae carbapenemase (KPC) and half producing Metallo-β-lactamase (MBL), two key enzymes contributing to carbapenem resistance. We determined the minimum inhibitory concentrations (MICs) of four antibiotics: eravacycline, tigecycline, polymyxin-B, and ceftazidime/avibactam. Synergistic interactions between these antibiotic combinations were examined using checkerboard and time-kill analyses. We noted significant differences in the MICs of ceftazidime/avibactam between KPC and MBL isolates. Checkerboard analysis revealed appreciable synergy between combinations of tigecycline (35%) or eravacycline (40%) with polymyxin-B. The synergy rates for the combination of tigecycline or eravacycline with polymyxin-B were similar among the KPC and MBL isolates. These combinations maintained a synergy rate of 70.6% even against polymyxin-B resistant isolates. In contrast, combinations of tigecycline (5%) or eravacycline (10%) with ceftazidime/avibactam showed significantly lower synergy than combinations with polymyxin-B (P < 0.001 and P = 0.002, respectively). Among the MBL CRKP isolates, only one exhibited synergy with eravacycline or tigecycline and ceftazidime/avibactam combinations, and no synergistic activity was identified in the time-kill analysis for these combinations. The combination of eravacycline and polymyxin-B demonstrated the most promising synergy in the time-kill analysis. This study provides substantial evidence of a significant synergy when combining tigecycline or eravacycline with polymyxin-B against CRKP strains, including those producing MBL. These results highlight potential therapeutic strategies against CRKP infections. [ABSTRACT FROM AUTHOR]

Extended-spectrum β-lactamases-producing Escherichia coli , Klebsiella pneumoniae , and Proteus mirabilis (ESBL-producing-EKP) are an increasingly common cause of childhood urinary tract infection (UTI) worldwide. Recognizing the risk factors and antimicrobial resistance patterns may guide new management in this population. This is a retrospective cohort study of over 5 years in Taiwan (2017–2021). Inclusion criteria are hospitalized pediatric patients with the discharge diagnosis of UTI caused by E. coli , Klebsiella pneumoniae , or Proteus mirabilis. ESBL-producing-EKP and non-ESBL-producing-EKP UTI cases were reviewed for characteristics , urinary isolate antibiotics resistance, and clinical outcomes. The incidence rate of ESBL-producing-EKP UTI increased over the study period (Overall incidence rate: 14.1 %, 46/327 patients). Recent antibiotic therapy in ≤6 months (X2 = 11.83, p < 0.01) and a preterm gestational history (X2 = 8.11, p < 0.05) were associated with an increased risk. The proportion of patients with these two risk factors for ESBL acquisition were 37.5 % (X2 = 9.08, p < 0.05). The co-resistance rate of ESBL-producing-EKP to other antimicrobial agents was 63.0 % for gentamicin, 56.5 % for trimethoprim-sulfamethoxazole, 52.2 % for ciprofloxacin, 4.3 % for amikacin, and 2.2 % for imipenem. The generalized linear model analysis identified a significantly longer length of stay (β: 2.85; 95 % confidence interval [CI]: 1.14–4.56; p < 0.01) and intensive care unit duration (β: 5.86; 95 % CI: 1.59–10.12; p < 0.01) among patients with ESBL-producing-EKP UTI. Amikacin should be considered as an alternative antimicrobial choice beyond carbapenems for ESBL-producing-EKP UTI, especially in the context of carbapenem-resistant E. coli/Klebsiella pneumoniae (CRE/CRKP) emergence. [ABSTRACT FROM AUTHOR]

Our objective was to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR) genes in fluoroquinolone-nonsusceptible Klebsiella pneumoniae (FQNSKP) in Taiwan, 1999–2022. A total of 938 FQNSKP isolates were identified from 1966 isolates. The presence of PMQR and virulence genes, antimicrobial susceptibility, capsular types, and PMQR-plasmid transferability were determined. An increasing number of PMQR-containing FQNSKP isolates were observed over the study period. Our results showed that 69.0% (647 isolates) of FQNSKP isolates contained at least one PMQR gene, and 40.6%, 37.0%, and 33.9% of FQNSKP carried aac(6′)-Ib-cr , qnrB , and qnrS , respectively. None of FQNSKP carried qepA and qnrC. The most common combination of PMQR genes was aac(6′)-Ib-cr and qnrB (12.3%). The presence of PMQR genes is strongly related to resistance to aminoglycoside, cephalosporin, tetracycline, and sulfamethoxazole/trimethoprim in FQNSKP. The capsular serotype K64 is the most common serotype we tested in both the non-PMQR and PMQR FQNSKP isolates, while K20 showed a higher prevalence in PMQR isolates. The magA and peg - 344 genes showed a significantly higher prevalence rate in non-PMQR isolates than in PMQR isolates. Eleven isolates that carried the PMQR and carbapenemase genes were identified; however, three successful transconjugants showed that the PMQR and carbapenemase genes were not located on the same plasmid. Our results indicated an increasing prevalence of PMQR genes, especially qnrB and qnrS , in FQNSKP in Taiwan. Moreover, the distribution of PMQR genes was associated with capsular serotypes and antimicrobial resistance gene and virulence gene distribution in FQNSKP. [ABSTRACT FROM AUTHOR]

The accelerating prevalence of extended-spectrum β-lactamase (ESBL)-producing and multidrug-resistance (MDR) Escherichia coli (E. coli) become a public health challenge worldwide. This study aimed to discuss the prevalence of drug-resistant E. coli colonization and analyze its risk factors and clinical characteristics among young infants in Southern Taiwan. Stool samples were collected from young infants, aged less than three months, within three days of their hospitalization from September to December 2019 in a tertiary hospital. A questionnaire was designed for parents to complete. E. coli colonies were selected and analyzed for antimicrobial susceptibility. PCR-based multilocus sequence typing was to detect the presence of sequence type ST131 and bla CTX-M genes. Among 100 enrolled infants, 36% had fecal carriage of E. coli isolates, of which twenty nine (80.5%) were MDR, thirteen (36.1%) were ESBL-producing isolates and five (13.8%) and ten (27.7%) were ST131 and strains carrying CTX-M-14 gene, respectively. Compared to non-ST131 and non-CTX-M-14 gene carrier, isolates of ST131 and CTX-M-14 gene carrier showed a significantly higher resistance rate to cefixime, ceftriaxone, and gentamycin, with p value all <0.05. The prevalence of ESBL-producing and MDR E. coli fecal carriage were both high in young infants. The most common sequence type is ST131, of which all are strains carrying CTX-M-14. Further surveillance and investigation to control for the high prevalence of antimicrobial-resistant E. coli fecal carriage among infants in Taiwan are warranted. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) is a growing worldwide public health issue due to the overuse and inappropriate use of antibiotics. AMR has been more prevalent during the coronavirus pandemic of 2019 (COVID-19) compared to previous periods. Therefore, this study was conducted to evaluate the AMR profile of common bacteria that were isolated for routine analysis during the pandemic of COVID-19 in Central Taiwan. The main goal of this study was to examine and analyze the AMR patterns both before and after the start of the COVID-19 pandemic. We conducted a retrospective analysis of clinical samples collected from two different time periods: the 1-year period before the onset of the COVID-19 pandemic (January 2019 to December 2019) and the 2-year period following the start of the pandemic (September 2020 to September 2022). The data for this study were obtained from clinical records, and both bacterial identification and antibiotic susceptibility testing were performed using the Phoenix identification system. Among the 8152 bacterial isolates obtained during the study period from September 2020 to September 2022, 4022 (49.3%) were Escherichia coli , 1346 (16.5%) were Klebsiella pneumoniae , 1156 (14.2%) were Staphylococcus aureus , 887 (10.9%) were Pseudomonas aeruginosa , 376 (4.6%) were Enterococcus faecium , and 365 (4.5%) were Acinetobacter baumannii. The overall prevalence of resistant bacteria during the COVID-19 pandemic was as follows: vancomycin-resistant Enterococcus, 69%; carbapenem-resistant A. baumannii, 65%; methicillin-resistant S. aureus, 49%; carbapenem-resistant K. pneumoniae, 29%; carbapenem-resistant P. aeruginosa, 17%; and carbapenem-resistant E. coli, 2%. Carbapenem-resistant A. baumannii , vancomycin-resistant Enterococcus , carbapenem-resistant K. pneumoniae , and carbapenem-resistant E. coli increased by 19%, 10%, 2%, and 1%, respectively. On the other hand, carbapenem-resistant P. aeruginosa and methicillin-resistant S. aureus decreased by 6%, respectively. This study provides a comprehensive assessment of AMR during the COVID-19 pandemic in Central Taiwan. Understanding the prevalence of AMR is crucial for preventing infection and formulating disease prevention policies. Further research is warranted to elucidate the correlation between AMR and the severity of infection in COVID-19 patients. [ABSTRACT FROM AUTHOR]

Respiratory culture screening is mandatory for all potential lung transplant donors. There is limited evidence on the significance of donor multidrug-resistant (MDR) bacteria on transplant outcomes. Establishing the safety of allografts colonized with MDR bacteria has implications for widening an already limited donor pool. We aimed to describe the prevalence of respiratory MDR bacteria among our donor population and to test for associations with posttransplant outcomes. This retrospective observational study included all adult patients who underwent lung-only transplantation for the first time at King Faisal Specialist Hospital & Research Centre in Riyadh from January 2015 through May 2022. The study evaluated donor bronchoalveolar lavage and bronchial swab cultures. Sixty-seven of 181 donors (37%) had respiratory MDR bacteria, most commonly MDR Acinetobacter baumannii (n = 24), methicillin-resistant Staphylococcus aureus (n = 18), MDR Klebsiella pneumoniae (n = 8), MDR Pseudomonas aeruginosa (n = 7), and Stenotrophomonas maltophilia (n = 6). Donor respiratory MDR bacteria were not significantly associated with allograft survival or chronic lung allograft dysfunction (CLAD) in adjusted hazard models. Sensitivity analyses revealed an increased risk for 90-day mortality among recipients of allografts with MDR Klebsiella pneumoniae (n = 6 with strains resistant to a carbapenem and n = 2 resistant to a third-generation cephalosporin only) compared to those receiving culture-negative allografts (25.0% versus 11.1%, p = 0.04). MDR Klebsiella pneumoniae (aHR 3.31, 95%CI 0.95-11.56) and Stenotrophomonas maltophilia (aHR 5.35, 95%CI 1.26-22.77) were associated with an increased risk for CLAD compared to negative cultures. Our data suggest the potential safety of using lung allografts with MDR bacteria in the setting of appropriate prophylaxis; however, caution should be exercised in the case of MDR Klebsiella pneumoniae. • Probable transmission occurred from 24% of donor lungs with MDR bacteria. • Respiratory MDR bacteria overall were not associated with adverse outcomes. • MDR K. pneumoniae was associated with 90-day mortality and chronic rejection. • S. maltophilia was associated with chronic rejection. [ABSTRACT FROM AUTHOR]

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We investigated the occurrence and distribution of genes encoding for extended-spectrum betalactamase (ESBL) production and quinolone resistance among multi-drug resistant (MDR) Escherichia coli and Klebsiella pneumoniae isolated from poultry, domestic pigs, and environment samples in the Msimbazi basin in Tanzania. A total of 130 non-duplicated isolates obtained from the poultry (n = 40), domestic pigs (n = 52) and environment (n = 38) were screened for ESBL genes (blaCTX-M, blaTEM, and blaSHV)and plasmid-mediated quinolone resistance (PMQR) genes (qnrA, qnrB, qnrS, qnrC, qnrD, qepA, and aac (6)-Ib-cr) using polymerase chain reaction (PCR). The most commonly detected ESBL genes were blaCTX-M (31.5%, n=41) and blaTEM (10%, n=13), while quinolone resistance genes were qnrS (27.7%, n=36), qnrB (6.9%, n=9) and aac (6)-lb-cr (5.4%, n=7). ESBL gene blaSHV and quinolone resistance genes qnrA, qnrC, and qepA were not detected in any of the isolates. Resistance genes were highest in isolates from the environmental samples (86%, n=33), followed by poultry 72.5% (n=29), and domestic pigs 21.4%, (n=9). Overall, the most frequent resistance gene was qnrS, followed by blaCTX-M and blaTEM. About 17.7% (n=23) of the E. coli and K. pneumoniae isolates depicted co-existence of ESBL and quinolone resistance genes. One Health interventional measures, involving different disciplines across human, animal, and environmental sectors, are needed to control the spread of antimicrobial resistance in the Msimbazi River Basin in Tanzania. [ABSTRACT FROM AUTHOR]

Cefiderocol (CFDC) is a novel siderophore-cephalosporin, which usually penetrates the bacteria through the iron-uptake pathways. Data is limited on the factors affecting CFDC activity and methods for overcoming resistance development. Synergistic approaches are needed to tackle antimicrobial resistance. This study aimed to determine CFDC activity on Klebsiella pneumoniae isolates from patients attending a single hospital in the United Arab Emirates (UAE), to explore the effect of β-lactamases on CFDC activity and to enhance CFDC susceptibility in both iron-depleted and iron-enriched conditions. We investigated 238 K. pneumoniae strains from diverse clinical sources. β-lactamase genes were detected by PCR. Susceptibility to CFDC and 12 comparator antibiotics were tested. Combinations of CFDC with β-lactamase inhibitors (BLIs) and/or an outer membrane (OM) permeabilizer (polymyxin B nonapeptide) were tested in iron-depleted and iron-enriched conditions. CFDC exhibited efficacy of 97.9%, against multidrug-resistant (MDR), and extensively drug-resistant (XDR) strains, in addition to strains resistant to the last resort drugs such as colistin and tigecycline, including dual carbapenemase-producers (bla NDM and bla OXA-48-like) with MIC ≤ 0.06–8 µg/ml. It was effective in killing strains with single and multiple β-lactamases; however, it lost activity in iron-enriched conditions. Synergy was achieved with dual combination of CFDC and BLIs, especially avibactam, which caused a significant reduction in MICs even in iron-enriched conditions. A significant reduction was seen with the triple combination including an OM permeabilizer plus avibactam. Killing-kinetic studies proved that the combination therapy caused dose reduction and faster killing by CFDC than the monotherapy. CFDC was deemed effective against MDR and XDR K. pneumoniae. Synergistic combination of CFDC with BLIs and OM permeabilizers could be effective to treat infections in iron-rich sites, but this should be investigated in vivo. [ABSTRACT FROM AUTHOR]

The global spread of Klebsiella pneumoniae ST15, causing multi-continental outbreaks, contributes to the movement of resistance genes between clones increasing the antimicrobial resistance crisis. The genomic traits providing it with the ability to outcompete other bacteria and cause epidemics remain unclear. To identify the specific genomic traits of K. pneumoniae ST15 to develop a diagnostic test. An outbreak caused by K. pneumoniae occurred in Hospital A Coruña, Spain. Antimicrobial susceptibility analysis and molecular typing (PGFE and MLST) were performed. One isolate of each sequence type was selected for whole-genome sequencing analysis. Comparative analysis of genomes was performed using RAST. BLASTn was used to evaluate the presence of the fhaC and kpiD genes. Two hundred and ninety-four K. pneumoniae from a Spanish nationwide collection were analysed by PCR. Genotyping showed that 87.5% of the isolates tested belonged to a clone with a unique PFGE pattern which corresponded to ST15. Comparative genomic analysis of the different STs enabled us to determine the specific genomic traits of K. pneumoniae ST15. Two adherence-related systems (Kpi and KpFhaB/FhaC) were specific markers of this clone. Multiplex-PCR analysis with kpiD and fhaC oligonucleotides revealed that K. pneumoniae ST15 is specifically detected with a sensitivity of 100% and a specificity of 97.76%. The PCR results showed 100% concordance with the MLST and whole-genome sequencing data. K. pneumoniae ST15 possesses specific genomic traits that could favour its dissemination. They could be used as targets to detect K. pneumoniae ST15 with high sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Background The presence of drug-resistant Gram-negative pathogenic bacteria and Extended Spectrum P-Lactamase Producers (ESBLs) in hospital associated fomites like door handles can serve as vehicles in transmission and may be the key factor in epidemiology of ESBL producing bacterial infection not only in a hospital setting but also in the community. The aim of this study was to determine the prevalence of ESBLs and antibiotic resistance of Gram-Negative pathogenic Bacteria isolated from door-handles in two selected hospitals in Pokhara Metropolitan City, Nepal. The study was conducted in selected hospitals in Pokhara Metropolitan City, Western Nepal. A cross-sectional study design was used. The hospitals were selected randomly. A total of 100 swab samples were taken from door-handles. Isolation and identification of bacteria were done using standard microbiological procedures. An antibiotic susceptibility test, screening and confirmation of ESBLs were performed using the Clinical Laboratory Standard Institute's guidelines. Results Out of the 100 swab samples cultured, 96 (96%) showed bacterial growth. A total of one hundred and forty isolates were isolated in this study which were further identified based on cultural, morphological and biochemical characteristics. The study also found that door handles/knobs had higher level of contamination in Outpatient Departments (OPDs), Emergency, Laboratory, General wards and Toilets, in that order as compared to Radiology Room, Staff rooms, Intensive Care Unit and Operation Theatre which were lower. The level of contamination varies depending on the traffic exposure and the environment. The most prevalent Gram-negative bacteria identified was Escherichia coli 28.85%, followed by Klebsiella spp 21.15%, Pseudomonas aeruginosa 15.38%, Proteus spp 11.54%, Enterobacter spp 9.62%, Acenetobacter spp 7.69%, Citrobacter spp 5.77%. The most effective drug of choice was Amikacin, Nitrofurantoin, Norfloxacin, Ciprofloxacin, Tetracycline and Imipenem for many Gram-negative isolates. The overall prevalence of ESBLs in this study was 27.14%. Out of total 15 Escherichia coli isolated, 11(73.3%), Klebsiella spp 9/11 (81.8%); Pseudomonas spp 7/8 (87.5%), Proteus spp 4/6 (66.6%); Enterobacter spp 3/5 (60%), Acenetobacter spp 3/4 (75%) and Citrobacter spp 1/3 (33.3%) were found to be Extended P-Lactamase Producers (ESBLs). Conclusion The isolation of of pathogenic Gram-negative bacteria and ESBLs in hospital environments and subsequent detection of high drug resistance patterns indicates a potentially serious public health challenge that strengthens the need for the effective and routine cleaning of door-handles in hospitals. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae causing nosocomial infections is increasingly multi-drug-resistant. Rapid and efficient typing tools are required for monitoring. To assess a simple, rapid (<5 h) multiplex polymerase chain reaction method based on multi-locus variable number tandem repeat analysis (MLVA) as a screening tool to determine whether or not K. pneumoniae strains are related. The global discriminatory power of the method was assessed on 72 unrelated K. pneumoniae isolates, including community carriage isolates, highly virulent strains causing liver abscess, and extended-spectrum beta-lactamase- and carbapenemase-producing strains. Suspected related strains from a suspected outbreak and a relapsed meningitis case were also studied. MLVA results were compared with whole-genome sequencing (WGS) analysis and multi-locus sequence typing (MLST). MLVA and MLST had similar discriminatory power, each distinguishing 54 profiles among the 72 unrelated isolates (Hunter–Gaston index 0.989). Each strain belonging to one sequence type (ST) or ST complex had its own MLVA type, with few exceptions. Two strains of ST268 and ST1119 shared the same MLVA profile, and two unrelated strains of ST307, ST86, ST45 and ST37 exhibited two different MLVA types each. Moreover, investigation of seven grouped cases of K. pneumoniae neonatal sepsis pointed to strong suspicion of a common source for five isolates, while two isolates with a different MLVA profile were excluded from this cluster. The MLVA approach is a useful, rapid and reliable tool for epidemiological investigation requiring only basic molecular biology equipment, and permits identification of sporadic isolates that are not part of an outbreak. However, analysis of strains sharing the same MLVA type by a highly discriminatory technique, such as WGS, remains necessary. [ABSTRACT FROM AUTHOR]

Bdellovibrio bacteriovorus is a bacterial agent that stands out for its ability to act as a predator against gram-negative bacteria and has found application against antibiotic-resistant pathogens. The aim of this study is to determine the efficacy of Bdellovibrio bacteriovorus against antibiotic-resistant pathogens, particularly those causing infections in surgical incision sites. A total of 6 experimental groups were created in mice, and surgical area infections were initiated with Klebsiella pneumoniae in incision sites. The effects of antibiotics and Bdellovibrio bacteriovorus alone or in combination were compared to the control group. In the Bdellovibrio bacteriovorus treatment group, edema and redness were observed in all mice at 24th hours, in 20% of mice at 48th hours, and in none at the 72 nd h. A significant difference was observed in the Bdellovibrio bacteriovorus treatment groups in reducing Klebsiella pneumoniae burden in the incision area compared to antibiotics alone or Bdellovibrio bacteriovorus + antibiotics, (p < 0.001). Likewise, cytokine level determinations indicated that B. bacteriovorus applications generated a therapeutic response without inducing an inflammatory response. • Surgical Site Infections (SSI) are the most common healthcare-associated infections, leading to increased workload and cost, as they prolong hospital stays, increase in morbidity and mortality, cause readmissions, and may require reoperation. • Infections caused by antibiotic-resistant gram-negative bacteria in SSI have been increasing in recent years and are reported to be associated with high levels of morbidity and mortality. • Resistance to antibiotic therapy used against gram-negative bacteria causes treatment to become increasingly difficult and increases the need for new types of treatments in clinics. • One of these approaches, which is the use of live bacteria such as Bdellovibrio bacteriovorus (B. bacteriovorus) to treat antibiotic-resistant pathogens, is considered one of the most promising possibilities. • This is the first study evaluating the efficacy of B. bacteriovorus on surgical site infections in experimental animals. [ABSTRACT FROM AUTHOR]

Transmission of infections via contaminated endoscopes is a common problem. Manual cleaning, using at least a detergent, is an important step in endoscope processing and should be performed as soon as possible to avoid drying of organic residues that might interfere with high-level disinfection and promote biofilm formation. To assess the efficacy of two detergent-disinfectants, enzymatic and non-enzymatic, and of an enzymatic detergent used during the manual cleaning against a Klebsiella pneumoniae biofilm. A 24 h biofilm statically formed in a Tygon tube was exposed to detergent-disinfectants at 20 °C and 35 °C for 10 mn, and to enzymatic detergent at 45 °C for 60 mn. The logarithmic reduction in bacteria in the Tygon tube and the number of bacteria in the product supernatant were calculated. Biofilm formation was reproducible between assays. After exposure to detergent-disinfectants, the logarithmic reduction was between 6.32 and 6.71 log 10 cfu/cm2 in the Tygon tubes. No bacteria were found in their supernatants. Results in the detergent-disinfectant group were not affected by the exposure temperature or the addition of enzymes. No decrease in the bacterial load was observed in the Tygon tubes after exposure to the enzymatic detergent. Bacteria were found in its supernatant. These results show the importance of the choice of products used during the manual cleaning phase. They also show the potential benefit of combining detergent and disinfectant activity to decrease the bacterial load during the manual cleaning step of endoscope processing. [ABSTRACT FROM AUTHOR]

Chlamydia-related bacteria of the Chlamydiales order have recently been described as emerging pathogens that cause pneumonia and abortion in animals and humans. We investigated the presence of Chlamydiales using real-time polymerase chain reaction (PCR) by targeting the 16S rRNA gene of a broad range of Chlamydiales in 827 fecal samples from pet birds kept in individual homes in Japan. Of the 827 samples, 493 (59.6%) tested positive for the Chlamydiales 16S rRNA gene in the real-time PCR assay. We determined the nucleic acid sequences of PCR products from 17 Chlamydiales strains. A homology search and phylogenetic analysis using these sequences confirmed that the detected Chlamydiales included C. pecorum and a broad range of Chlamydiarelated bacteria. To the best of our knowledge, this is the first study to detect a wide range of Chlamydia-related bacteria in birds. [ABSTRACT FROM AUTHOR]

Polymyxin B and polymyxin E (colistin) are presently considered the last line of defense against human infections caused by multidrug-resistant Gram-negative organisms such as carbapenemase-producer Enterobacterales , Acinetobacter baumannii , and Klebsiella pneumoniae. Yet resistance to this last-line drugs is a major public health threat and is rapidly increasing. Polymyxin S 2 (S 2) is a polymyxin B analogue previously synthesized in our institute with obviously high antibacterial activity and lower toxicity than polymyxin B and colistin. To predict the possible resistant mechanism of S 2 for wide clinical application, we experimentally induced bacterial resistant mutants and studied the preliminary resistance mechanisms. Mut-S, a resistant mutant of K. pneumoniae ATCC BAA-2146 (Kpn2146) induced by S 2 , was analyzed by whole genome sequencing, transcriptomics, mass spectrometry and complementation experiment. Surprisingly, large-scale genomic inversion (LSGI) of approximately 1.1 Mbp in the chromosome caused by IS 26 mediated intramolecular transposition was found in Mut-S, which led to mgrB truncation, lipid A modification and hence S 2 resistance. The resistance can be complemented by plasmid carrying intact mgrB. The same mechanism was also found in polymyxin B and colistin induced drug-resistant mutants of Kpn2146 (Mut-B and Mut-E, respectively). This is the first report of polymyxin resistance caused by IS 26 intramolecular transposition mediated mgrB truncation in chromosome in K. pneumoniae. The findings broaden our scope of knowledge for polymyxin resistance and enriched our understanding of how bacteria can manage to survive in the presence of antibiotics. An inversion of approximately 1.1 Mbp due to IS 26 intramolecular transposition caused mgrB truncation in chromosome of K. pneumoniae , which led to LPS modifications, and hence resistance to polymyxins. [Display omitted] [ABSTRACT FROM AUTHOR]

d-Aldotetroses are rare sugars that are obtained via chemical synthesis in low yield. In this study, we demonstrated that d-aldotetroses could be produced using 3 isomerases. First, l-erythrulose was epimerized using d-tagatose 3-epimerase from Pseudomonas cichorii ST-24. The specific optical rotation of the reaction solution gradually decreased to zero, indicating that approximately 50% of the l-erythrulose was converted to d-erythrulose. d, l-Erythrulose mixture was isomerized with d-arabinose isomerase from Klebsiella pneumoniae 40bXX to produce d-threose, resulting in a conversion rate of 9.35%. d-Erythrose production using l-rhamnose isomerase from Pseudomonas stutzeri LL172 resulted in a conversion rate of 12.9%. Because of the low purity of the purchased d-erythrose, the product was reduced by the Raney nickel catalyst compared with authentic erythritol. We confirmed the products using HPLC and 13C-NMR spectra. This is the first report of d-aldotetrose production using an enzymatic reaction. [ABSTRACT FROM AUTHOR]

We focused on streptomycin resistance because of the high percentage of streptomycin-resistant Escherichia coli concerning the amount used of streptomycin. Antimicrobial resistance and horizontal transfer were identified in 117 isolates of coliform bacteria from chicken meat to identify the factors that increase streptomycin resistance. Escherichia (45 isolates) was the predominant genus. Most streptomycin-resistant Escherichia isolates were resistant to other antimicrobials (17/18), suggesting that using various antimicrobials could select streptomycinresistant Escherichia isolates. Resistance was transferred from 7 out of the 18 streptomycin-resistant isolates. The transconjugants acquired strA/strB (7/7), blaTEM (5/7), aphA 1 (5/7), tetB (3/7), dfrA 14 (1/7) and/or dfrA17 (1/7). The co-resistance of streptomycin resistance with other resistances would also increase streptomycin resistance. [ABSTRACT FROM AUTHOR]

To investigate the distribution and antimicrobial susceptibility of causative microorganisms recovered from patients with intra-abdominal infections (IAIs). A total of 2,926 bacterial and fungal strains were identified in samples collected from 1,679 patients with IAIs at the Peking Union Medical College Hospital between 2011 and 2021. Pathogenic bacteria and fungi were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antimicrobial susceptibility testing (AST) was performed using the VITEK 2 compact system and the Kirby–Bauer method. AST results were interpreted based on the M100-Ed31 clinical breakpoints of the Clinical and Laboratory Standards Institute. Of the 2,926 strains identified, 49.2%, 40.8%, and 9.5% were gram-negative bacteria, gram-positive bacteria, and fungi, respectively. Escherichia coli was the most prevalent pathogen in intensive care unit (ICU) and non-ICU patients; however, a significant decrease was observed in the isolation of E. coli between 2011 and 2021. Specifically, significant decreases were observed between 2011 and 2021 in the levels of extended-spectrum β-lactamase (ESBL)-producing E. coli (from 76.9% to 14.3%) and Klebsiella pneumoniae (from 45.8% to 4.8%). Polymicrobial infections, particularly those involving coinfection with gram-positive and gram-negative bacteria, were commonly observed in IAI patients. Moreover, Candida albicans was more commonly isolated from hospital-associated IAI samples, while Staphylococcus epidermidis had a higher ratio in community-associated IAIs. Additionally, AST results revealed that most antimicrobial agents performed better in non-ESBL-producers than in ESBL-producers, while the overall resistance rates (56.9%–76.8%) of Acinetobacter baumanmii were higher against all antimicrobial agents than those of other common gram-negative bacteria. Indeed, Enterococcus faecium , Enterococcus faecalis , S. epidermidis , and S. aureus were consistently found to be susceptible to vancomycin, teicoplanin, and linezolid. Similarly, C. albicans exhibited high susceptibility to all the tested antifungal drugs. The distribution and antimicrobial susceptibility of the causative microorganisms from patients with IAIs were altered between 2011 and 2021. This finding is valuable for the implementation of evidence-based antimicrobial therapy and provides guidance for the control of hospital infections. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to describe the epidemiological characteristics of carbapenemaseproducing Enterobacteriaceae (CPE) outbreaks in healthcare settings in the Republic of Korea between 2017 and 2022. Methods: Under the national notifiable disease surveillance system, we obtained annual descriptive statistics regarding the isolated species, carbapenemase genotype, healthcare facility type, outbreak location and duration, and number of patients affected and recommended interventions. We used epidemiological investigation reports on CPE outbreaks reported to Korea Disease Control and Prevention Agency from June 2017 to September 2022. Results: Among the 168 reports analyzed, Klebsiella pneumoniae (85.1%) was the most frequently reported species, while K. pneumoniae carbapenemase (KPC, 82.7%) was the most common carbapenemase genotype. Both categories increased from 2017 to 2022 (p <0.01). General hospitals had the highest proportion (54.8%), while tertiary general hospitals demonstrated a decreasing trend (p <0.01). The largest proportion of outbreaks occurred exclusively in intensive care units (ICUs, 44.0%), and the frequency of concurrent outbreaks in ICUs and general wards increased over time (p<0.01). The median outbreak duration rose from 43.5 days before the coronavirus disease 2019 (COVID-19) pandemic (2017-2019) to 79.5 days during the pandemic (2020-2022) (p=0.01), and the median number of patients associated with each outbreak increased from 5.0 to 6.0 (p=0.03). Frequently recommended interventions included employee education (38.1%), and 3 or more measures were proposed for 45.2% of outbreaks. Conclusion: In the Republic of Korea, CPE outbreaks have been consistently dominated by K. pneumoniae and KPC. The size of these outbreaks increased during the COVID-19 pandemic. Our findings highlight the need for continuing efforts to control CPE outbreaks using a multimodal approach, while considering their epidemiology. [ABSTRACT FROM AUTHOR]

Hypervirulent Klebsiella pneumoniae (hvKp) is an emerging pathotype in addition to classical Klebsiella pneumoniae, with its ability to cause life-threatening, community-acquired metastatic infections even in healthy individuals. We presented a case of cerebral abscess preceded by otitis media in a 10-year-old child caused by hvKp. The isolates from blood pus aspirate were later identified as K. pneumoniae capsular serotype K2 and closely related to sequence type (ST65), with multiple hypervirulent genes detected (rmpA, rmpA2 , iucA and peg344). She succumbed to death despite surgical drainage and susceptible antibiotic therapy. Clinicians should be cognizant of the rising incidence of hvKp infections in pediatric populations. [ABSTRACT FROM AUTHOR]

A series of new monobactam sulfonates is continuously synthesized and evaluated for their antimicrobial efficacies against Gram-negative bacteria. Compound 33a (IMBZ18G) is highly effective in vitro and in vivo against clinically intractable multi-drug-resistant (MDR) Gram-negative strains, with a highly druglike nature. The checkerboard assay reveals its significant synergistic effect with β -lactamase inhibitor avibactam, and the MIC values against MDR enterobacteria were reduced up to 4–512 folds. X-ray co-crystal and chemoproteomic assays indicate that the anti-MDR bacteria effect of 33a results from the dual inhibition of the common PBP3 and some class A and C β -lactamases. Accordingly, preclinical studies of 33a alone and 33a ‒avibactam combination as potential innovative candidates are actively going on, in the treatment of β -lactamase-producing MDR Gram-negative bacterial infections. IMBZ18G is highly effective against MDR Gram-negative bacteria, with the dual inhibition on PBP3 and class A and C β -lactamases. IMBZ18G-avibactam combination further broadens the antibacterial application of IMBZ18G. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Cukurova Medical Journal / Çukurova Üniversitesi Tip Fakültesi Dergisi is the property of Cukurova University, Faculty of Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cukurova Medical Journal / Çukurova Üniversitesi Tip Fakültesi Dergisi is the property of Cukurova University, Faculty of Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The susceptibility of 218 extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae isolates from companion animals to three cephamycins (cefmetazole, flomoxef, and latamoxef) was investigated. Phenotypic testing found 8 of 120 Klebsiella pneumoniae (KP) and 15 of 69 Enterobacter cloacae (EC) isolates were ESBL and AmpC ß-lactamase (ABL) co-producers. Isolates of KP, Proteus mirabilis, and EC that only produced ESBL exhibited susceptibility rates to cefmetazole (95.5%, 82.7%, and 9.3%), flomoxef (99.1%, 96.6%, and 74.0%), and latamoxef (99.1%, 100%, and 100%), respectively. Notably, isolates of KP and EC co-producing ESBL and ABL had significantly lower susceptibility rates to the studied drugs when compared with only ESBL producers. This implies that the in vitro activity of cephamycins against ESBL-producing bacteria can differ depending on ABL production and bacterial species. [ABSTRACT FROM AUTHOR]

We monitored swine-derived Escherichia coli on a Japanese farm where colistin had been used for the treatment of diseases caused by bacteria and investigated colistin resistance and the presence of mcr-1 in 36 E. coli strains isolated before and after the withdrawal of colistin use. Through the withdrawal of colistin use on the farm, the prevalence of colistin-resistant and mcr-1-positive E. coli was markedly reduced but not eradicated because mcr-1 had been maintained in multiple plasmids and various sequence types of nonpathogenic E. coli carried in healthy swine. The monitoring of sequence types of mcr-1-positive E. coli is expected to be important for controlling colistin resistance in swine or other animals. [ABSTRACT FROM AUTHOR]

Extended-spectrum beta-lactamase-producing Enterobacterales (eESBL) have high prevalence in hospitals, but real-time monitoring of nosocomial acquisition through conventional typing methods is challenging. Moreover, patient-to-patient transmission varies between the main species, namely Escherichia coli and Klebsiella pneumoniae , which draws into question the relevance of applying identical preventive measures. To detect eESBL cross-transmission events (CTEs) using the quantitative antibiogram (QA) method in combination with epidemiological data (combined QA method), and to determine the effectiveness of standard or contact precautions for eESBL species. First, a validation set was used to compare the relevance of the combined QA method with a combination of pulsed-field gel electrophoresis and epidemiological data (combined PFGE method). Next, a 4-year retrospective analysis was conducted to detect eESBL CTEs in hospitalized patients. Two species were screened – ESBL E. coli (ESBL-Ec) and ESBL K. pneumoniae (ESBL-Kp). During the study, standard precautions alone were applied to patients with ESBL-Ec, whereas contact precautions were applied for patients with ESBL-Kp. As a proof of concept, use of the combined QA method and the combined PFGE method for the detection of CTEs gave identical results for E. coli , and similar results for at least 75% of K. pneumoniae. Overall, 722 patients with ESBL-Ec isolates and 280 patients with ESBL-Kp isolates were included in the retrospective analysis. Nine and 23 CTEs were identified for E. coli and K. pneumoniae , respectively, involving 20 (2.7%) and 36 (12.8%) patients, respectively. The combined QA method constitutes a rapid tool for epidemiological surveillance to detect CTEs. In the study hospital, standard precautions are sufficient to prevent acquisition of ESBL-Ec, whereas contact precautions must be implemented to prevent acquisition of ESBL-Kp. [ABSTRACT FROM AUTHOR]

Infectious complications of parietal mesh after prosthetic abdominal wall repair are rare. Their management is complex. Furthermore, the emergence of bacterial resistance, the presence of a foreign material, the need to continue an extended antibiotic therapy, and the choice of an appropriate treatment are crucial. The objective of this study is to access the microbiological epidemiology of infected parietal meshes in order to optimize the empirical antibiotic therapy. Between January 2016 and December 2021, a monocentric and retrospective study was performed in patients hospitalized for infected parietal meshes at Avicenne hospital, in Paris area. Clinical and microbiological data such as antibiotic susceptibility were collected. Twenty-six patients with infected parietal meshes have been hospitalized during this period. Meshes were in preaponevrotic positions (n = 10; 38%), retromuscular (n = 6; 23%) and intraperitoneal (n = 10; 38%). Among the 22 (84.6%) documented cases of infections, 17 (77.3%) were polymicrobial. A total of 54 bacteria were isolated, 48 of which had an antibiogram available. The most frequently isolated bacteria were: Enterobacterales (n = 19), Enterococcus spp. (n = 11) and Staphylococcus aureus (n = 6), whereas anaerobes were poorly isolated (n = 3). Concerning these isolated bacteria, amoxicillin-clavulanic acid, metronidazole-associated cefotaxime, piperacillin-tazobactam and meropenem were susceptible in 45.5%, 68.2%, 63.6%, 77.2%, of cases, respectively. This work highlights that infections of abdominal parietal meshes may be polymicrobial and the association amoxicillin-clavulanic acid cannot be used as a probabilist antibiotic therapy because of the high resistance rate in isolated bacteria. The association piperacillin-tazobactam appears to be a more adapted empirical treatment to preserve carbapenems, a broad-spectrum antibiotic class. [ABSTRACT FROM AUTHOR]

Hypervirulent Klebsiella pneumoniae (hvKp) infections confer notable morbidity and mortality. Differential diagnosis to determine whether the infections are caused by either the hvKp or classical K. pneumoniae (cKp) strain is particularly important for undertaking optimal clinical care and infection control efforts. To identify and assess the potential predictors of hvKp infections. PubMed, Web of Science, and Cochrane Library databases were searched for all relevant publications from January 2000 to March 2022. The search terms included a combination of the following terms: (i) Klebsiella pneumoniae or K. pneumoniae and (ii) hypervirulent or hypervirulence. A meta-analysis of factors for which risk ratio was reported in three or more studies was conducted, and at least one statistically significant association was identified. In this systematic review of 11 observational studies, a total of 1392 patients with K. pneumoniae infection and 596 (42.8%) with hvKp strains were evaluated. In the meta-analysis, diabetes mellitus and liver abscess (pooled risk ratio: 2.61 (95% confidence interval: 1.79–3.80) and 9.04 (2.58–31.72), respectively; all P < 0.001) were predictors of hvKp infections. For patients with a history of the abovementioned predictors, prudent management, including the search for multiple sites of infection and/or metastatic spread and the enforcement of an early and appropriate source control procedure, should be initiated in consideration of the potential presence of hvKp. We believe that this research highlights the urgent need for increasing clinical awareness of the management of hvKp infections. [ABSTRACT FROM AUTHOR]

Copyright of Salud Uninorte is the property of Fundacion Universidad del Norte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Healthcare-associated infections (HCAIs) caused by extended spectrum β-lactamase-producing Gram-negative bacteria (ESBL-GNB) increase morbidity and mortality. This cross-sectional study characterised ESBL genes (bla CTX-M, bla TEM and bla SHV) among 30 ceftriaxone-resistant GNB causing HCAIs between January 2022 and July 2022 by multiplex polymerase chain reaction assay at the zonal referral hospital in Mwanza, Tanzania. Twenty-five (83.3%) had at least one ESBL gene, of which 23/25 (92.0%) carried the bla CTX-M gene. Seventy-two percent (18/25) of the GNB-ESBL isolates carried more than one ESBL gene, of which the majority (88.8%; n = 16/25) carried the bla CTX-M and bla TEM genes. Extended spectrum β-lactamase genes, particularly bla CTX-M, are common among ceftriaxone-resistant GNB causing HCAIs. What this study adds: This study revealed the distribution of genes (bla CTX-M, bla TEM and bla SHV) coding for ESBL production among ceftriaxone resistant GNB causing HCAIs However, all ESBL producing GNB were susceptible towards ceftriaxone-sulbactam indicating that ceftriaxone-sulbactam may be empirically prescribed for treating patients with HCAIs. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Natural dyes are present in living organisms such as animals and plants and microorganisms such as fungi, bacteria, algae, and yeast. Pigments are fast and easy growth by using cheap components and do not effect by environmental conditions because they required some physical factors like heat, light, and pH and also they have many biotechnological applications such as medical and industrial needs. The natural pigments can act as antimicrobial agents and are used in drug manufacturing. Also, it can be used in the food industry as natural colorants instead of the synthetic colorants due to their safety on human health and low toxicity when emitted into the environment. Results: A pigmented actinomycetes LS1 strain isolated from El Mahmoudia canal (sediment soil) located in Egypt was microscopically examined and identified as Streptomyces sp. by molecular approach. Extraction, purification, and characterization of produced red pigment metabolite like carotenoids related were established based on spectroscopic studies and comparing the data from the literature. Factors (nutritional and physical) influencing red pigmentation by this isolate were investigated through One Variable At Time (OVAT), and then, the optimal levels of the significant key variables were recorded. Also, the productivity yield reached 30 mg of dried purified pigment/gram dry weight. The biological activity of the red product was tested against Gram-positive and Gram-negative marine bacterial pathogens; the recorded antimicrobial activity is more prominent against (P. aeruginosa ATCC 9027, K. pneumoniae ATCC 13883, S. aureus ATCC 6538, B. subtilis ATCC 6633 and E. coli ATCC 10418) at nearly 0.07 mg mL−1 concentration. Also, the tested red pigment showed a positive antifouling activity (AF) against marine microbes; the activity increased by increasing the pigment concentrations from 1 to 3 mg mL−1. Conclusion: The present work focused on the optimization of culture conditions for the production of red pigment by Streptomyces sp. LS1; then, the antibacterial activity and antifouling activity of the produced pigments were tested. [ABSTRACT FROM AUTHOR]

Background: Previous studies have reported a strong association between gut microbiome and hypertension; yet, the exact bacterial species associated with the disease development and progression have not yet been detected. This study aimed to investigate whether opportunistic pathogen Klebsiella pneumoniae is a causal factor for hypertension pathogenesis, and explore the potential mechanisms.Methods: The enrichment of Klebsiella pneumoniae in the gut of patients with hypertension was validated by meta-analysis based on 3 independent cohorts. Klebsiella pneumoniae was inoculated into germ-free mice, antibiotic pretreated and conventional mice.Results: Klebsiella pneumoniae led to higher blood pressure, slight cardiac hypertrophy, and enhanced contractility of resistant arteries in recipient mice. Moreover, Klebsiella pneumoniae induced pathological damages, deficiency of tight junction proteins and transcriptional shifts. Metabolic alterations, especially the depletion of stearoylethanolamide, were observed upon Klebsiella pneumoniae administration. In addition, renal transcriptome dysfunction with significant upregulation of genes related to hypertension pathogenesis was observed in Klebsiella pneumoniae treated mice.Conclusions: These results provide evidence that the enrichment of Klebsiella pneumoniae acts as a direct contributor to blood pressure elevation and hypertension pathogenesis, and Klebsiella pneumoniae induced intestinal damages, fecal metabolic changes, and renal shifts may be integrated mediators. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae is a leading cause of severe infections in humans and animals, and the emergence of multidrug-resistant strains highlights the need to develop effective vaccines for preventing such infections. Live attenuated vaccines are attractive vaccine candidates available in the veterinary field. We recently characterized that the K. pneumoniae kbvR (Klebsiella biofilm and virulence regulator) mutant was a highly attenuated strain in the mice model. In the present study, the characterization, safety, and protective efficacy of ΔkbvR strain as a live attenuated vaccine were evaluated. The synthesis and activity of type 1 fimbriae were increased in the ΔkbvR strain. All mice inoculated by the subcutaneous route with 105, 106, and 107 colony-forming units (CFU) doses of the ΔkbvR strain survived. Subcutaneous immunization with two doses of 105 or 107 CFU ΔkbvR elicited a robust humoral immune response, and provided protection against the following K. pneumoniae intraperitoneal infection. The antisera of mice immunized with 105 CFU dose improved the opsonophagocytic ability and complement-mediated lysis not only to the same serotype strain but also to the different serotype strain. The passive transfer of antisera from 105 CFU dose-immunized mice provided protection against K. pneumoniae infection. Overall, our results suggest the great potential of the ΔkbvR strain as a novel vaccine candidate against K. pneumoniae infections in herds or humans. [ABSTRACT FROM AUTHOR]

Background: Surveillance of carbapenem-resistant Enterobacterales (CRE) carriers is the first measure of hospital infection control. Screening of CRE carriage can be assessed through culture and molecular techniques, each with specific properties of turnaround-times, sensitivity and specificity.Methods: This was a prospective study in a 1200-bed university hospital in Genoa, Italy, where CRE screening is performed analysing cultures from rectal swabs. Our 18-months intervention was to extend the incubation time of the corresponding plates from 48 to 288 h, after reporting negative tests, to evaluate the possible impact on the cultures.Findings: A total of 362 patients giving 19,278 swabs and corresponding plates were included. After baseline incubation, plate positivity was 3%, while after the overall lengthened times it was 3.7%. Extended incubation was associated with change in the relative frequency of the most represented species. In particular, we observed reduced presence of total and resistant Klebsiella pneumoniae strains (P<0.001) and increased presence of Enterobacter cloacae complex, total and sensitive (P<0.001). By extending incubation time, a reduced frequency of overall Enterobacterales strains with high resistance to ertapenem (MIC ≥4 mg/L) was also found (P=0.005), particularly that of K. pneumoniae (P<0.001), while the presence of E. cloacae complex increased among organisms with low resistance levels to ertapenem (P<0.001).Conclusions: Extending the incubation time of the cultures increased the number of CREs grown, and expanded the bacterial scenario of rectal colonization through the recovery of poorly resistant strains and otherwise undetected species. [ABSTRACT FROM AUTHOR]

The presence of carbapenemase enzymes among Enterobacterales is the main mechanism to reduce susceptibility to a wide range of antibiotics. Carbapenemase enzymes such as the Klebsiella pneumoniae carbapenemase (KPC) hydrolyse beta-lactam antibiotics group, which includes carbapenem, leads to fewer treatment options. We aim to describe the first report of carbapenem-resistant K. pneumoniae (CRKP) sequence type (ST) 11 harbouring KPC in Oman. Five confirmed CRKP isolates were isolated from clinical samples during the period of January 2019 till December 2019. Strains were genotyped by pulse field gel electrophoresis (PFGE) for genetic relatedness. Whole genome sequencing (WGS) was performed to observe relationships with global strains using multilocus sequence typing (MLST). Antimicrobial genes, capsular loci-K-types, plasmids types and virulence genes were also identified using whole genome sequence data. All five CRKP were determined to have bla KPC-2 with or without bla OX-A48 and bla NDM-2. The molecular genotyping by PFGE showed 100% similarity among the five isolates. The MLST allelic profile analysis clonally clustered our strains with SL-258, CG-11 and ST11 mainly reported from South Asia. Further molecular characterization of the capsular K-locus and O-locus genes, revealed the strains to belong to KL-47 type and OL101 type respectively. The core genome typing suggests that our strains were clonally related to Chinese strains with less than five chromosomal nucleotides differences. Epidemiological and molecular analyses confirmed that these KPC-producing K. pneumoniae strains are from a single clone that caused multiple nosocomial infections in one health institution. This finding highlights the importance to sustain the surveillance and infection prevention efforts and to step up active screening to prevent the spread of nosocomial infection. [ABSTRACT FROM AUTHOR]

Introduction and Objective. Klebsiella pneumoniae is an essential component of the human gut microflora. However, it can pose a threat by causing opportunistic infections, especially in hospitalised or immunocompromised patients. It is a serious problem for health medicine, primarily because of increasing resistance to previously used antibiotics. Infections with multidrug-resistant strains are difficult to treat, creating a challenge for clinicians. Also of growing concern is the increasing resistance to the drug of last resort - colistin (CL). The aim of the study is to determine the prevalence of resistance to CL among clinical K. pneumoniae strains. Materials Method. The study was conducted on 200 clinical strains of K. pneumoniae. Drug susceptibility, production of resistance mechanisms, and determination of the minimum inhibitory concentration of CL were evaluated. Results. Of all isolates, 73.0% produced carbapenemases, while the remainder produced an extended substrate spectrum - β-lactamases (ESBLs). All strains showed a diverse antibiotic resistance profile. Resistance to CL was noted among 14.5% of carbapenemase-producing strains, particularly MBL and OXA-48. ESBL-positive strains showed full susceptibility to CL. Conclusions. Although a low rate of CL resistance was observed, this was true for strains simultaneously producing carbapenemases. Such strains should be under special epidemiological surveillance due to their potential to cause epidemic outbreaks. Monitoring the prevalence of clinical CL-resistant strains would allow for more effective counteraction against pathogens in various fields, including medicine, agriculture, veterinary medicine and industry. [ABSTRACT FROM AUTHOR]

The global dissemination of carbapenemase genes, particularly bla NDM-1 , poses a significant threat to public health. While research has mainly focused on strains with phenotypic resistance, the impact of silent resistance genes has been largely overlooked. This study documents the first instance of silent bla NDM-1 in a cluster of clonally related carbapenem-susceptible K. pneumoniae strains from a single patient. Despite initial effectiveness of carbapenem therapy, the patient experienced four recurrent lung infections over five months, indicating persistent K. pneumoniae infection. Genomic sequencing revealed all strains harbored bla NDM-1 on the epidemic IncX3 plasmid. A deletion within the upstream promoter region (P IS Aba125) of bla NDM-1 hindered its expression, resulting in phenotypic susceptibility to carbapenems. However, in vitro bactericidal assays and a mouse infection model showed that K. pneumoniae strains with silent bla NDM-1 exhibited significant tolerance to carbapenem-mediated killing. These findings demonstrate that silent bla NDM-1 can mediate both phenotypic susceptibility and antibiotic tolerance. In silico analysis of 1986 bla NDM sequences showed that 1956 (98.5%) retained the original promoter P IS Aba125. Given that previous genomic sequencing typically targets carbapenem-resistant strains, accurately assessing the prevalence of silent bla NDM remains challenging. This study highlights the hidden threat of silent resistance genes to clinical antimicrobial therapy and calls for enhanced clinical awareness and laboratory detection. [ABSTRACT FROM AUTHOR]

The carbapenem-resistant Klebsiella pneumoniae poses a serious threat to public health because carbapenems are used as a final resort to treat K. pneumoniae -mediated infections in humans. Samples were collected from various clinical specimens including skin swabs, anal swabs, wound swabs, oral swabs, and sputum by the standard method and K. pneumoniae strains were isolated. Biofilm-forming characters were determined. The antibiotic resistance pattern was analyzed by the Kirby–Bauer disk diffusion method. Carbapenem resistance properties were tested using the imipenem and meropenem antibiotics. The carbapenemase genes (bla KPC and bla NDM) were determined. A total of 11 cephalosporin-resistant K. pneumoniae (CRKP) strains were isolated from the samples. The screened CRKP strains exhibited multi-drug resistance and non-susceptible to imipenem, ceftazidime, piperacillin, ceftriaxone, cefazolin, ampicillin, aztreonam, and cefotetan antibiotics. A total of 79.4 % K. pneumoniae isolates showed positive results on String-forming test. About 82.1 % of isolates showed mucoid colonies and 59 % of K. pneumoniae strains formed biofilm (p < 0.01). Out of 11 isolates, four strains exhibited Klebsiella pneumoniae carbapenemase type, three strains produced metallo-β-lactamases (MBL), and four strains exhibited as carbapenemase types. A total of 63.5 % Klebsiella pneumoniae carbapenemase-producing strains showed very low MIC value (<0.05 mg/L). Drug-resistance K. pneumoniae was isolated from clinical specimens that were screened. The continuous monitoring of drug-resistance genes are required to make policy decisions. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae is an important etiological agent of nosocomial infections. This study focuses on the antibacterial activity of Persea Americana extract against K. pneumoniae strains containing aminoglycoside genes. Broth microdilution technique was used to examine the antibacterial activity of P. americana extract on K. pneumoniae isolates. The phenolic components of its leaves were analysed by the HPLC-DAD system. The binding potential of the major phytochemical component of the extract, chlorogenic acid, to the KsgA was investigated by molecular docking. The stability of the resulting enzyme-ligand complexes was also assessed through molecular dynamics simulation. The result obtained showed that P. americana extract had antibacterial activity on aminoglycoside resistant strains. The binding potential of chlorogenic acid (main phenolic compound) to KsgA was found to be higher than the binding of gentamicin. Since chlorogenic acid had lower binding energy and formed higher number of H-bonding as well as other interactions in the docking analysis. The higher binding potential of the major component with the enzyme that was involved in resistance development against aminoglycoside indicated its possible role in overturning the condition. Moreover, the molecular dynamics simulation study revealed that chlorogenic acid formed a complex with relatively higher stability. The higher binding potential of the major component with higher stability implied that the computational results confirmed the experimental findings. • Antibacterial activity of avocado extracts against K. pneumoniae was tested. • Binding potential of chlorogenic acid to the KsgA was examined by molecular docking. • Stability of enzyme-ligand complexes was assessed by molecular dynamics simulation. • Chlorogenic acid had lower binding energy and formed higher number of H-bonding. • Chlorogenic acid had higher binding potential than gentamicin. [ABSTRACT FROM AUTHOR]

• Scutellaria baicalensis ameliorates lower respiratory tract infection in mice. • Lower respiratory tract infections are related to respiratory microbiota dysbiosis. • Scutellaria baicalensis regulates IL-17A and GM-CSF in a microbiota-dependent manner. • Scutellaria baicalensis may target IL-17A and GM-CSF to resist infection in mice. • Scutellaria baicalensis modulates the respiratory microbiota in mice after infection. The pathogenesis of lower respiratory tract infections (LRTIs) has been demonstrated to be strongly associated with dysbiosis of respiratory microbiota. Scutellaria baicalensis , a traditional Chinese medicine, is widely used to treat respiratory infections. However, whether the therapeutic effect of S. baicalensis on LRTIs depends upon respiratory microbiota regulation is largely unclear. To investigate the potential effect and mechanism of S. baicalensis on the respiratory microbiota of LRTI mice. A mouse model of LRTI was established using Klebsiella pneumoniae or Streptococcus pneumoniae. Antibiotic treatment was administered, and transplantation of respiratory microbiota was performed to deplete the respiratory microbiota of mice and recover the destroyed microbial community, respectively. High-performance liquid chromatography (HPLC) was used to determine and quantify the chemical components of S. baicalensis water decoction (SBWD). Pathological changes in lung tissues and the expressions of serum inflammatory cytokines, including interleukin-17A (IL-17A), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), were determined by hematoxylin and eosin (H&E) staining and enzyme-linked immunosorbent assay (ELISA), respectively. Quantitative real-time PCR (qRT-PCR) analysis was performed to detect the mRNA expression of GM-CSF. Metagenomic sequencing was performed to evaluate the effect of SBWD on the composition and function of the respiratory microbiota in LRTI mice. Seven main components, including scutellarin, baicalin, oroxylin A-7-O- β -d-glucuronide, wogonoside, baicalein, wogonin, and oroxylin A, were identified and their levels in SBWD were quantified. SBWD ameliorated pulmonary pathological injury and inflammatory responses in K. pneumoniae and S. pneumoniae -induced LRTI mice, as evidenced by the dose-dependent reductions in the levels of serum inflammatory cytokines, IL-6 and TNF-α. SBWD may exert a bidirectional regulatory effect on the host innate immune responses in LRTI mice and regulate the expressions of IL-17A and GM-CSF in a microbiota-dependent manner. K. pneumoniae infection but not S. pneumoniae infection led to dysbiosis in the respiratory microbiota, evident through disturbances in the taxonomic composition characterized by bacterial enrichment, including Proteobacteria, Enterobacteriaceae , and Klebsiella. K. pneumoniae and S. pneumoniae infection altered the bacterial functional profile of the respiratory microbiota, as indicated by increases in lipopolysaccharide biosynthesis, metabolic pathways, and carbohydrate metabolism. SBWD had a certain trend on the regulation of compositional disorders in the respiratory flora and modulated partial microbial functions embracing carbohydrate metabolism in K. pneumoniae -induced LRTI mice. SBWD may exert an anti-infection effect on LRTI by targeting IL-17A and GM-CSF through respiratory microbiota regulation. The mechanism of S. baicalensis action on respiratory microbiota in LRTI treatment merits further investigation. [Display omitted] [ABSTRACT FROM AUTHOR]

Green copper nanoparticles (M-Cu NPs) were successfully synthesised by using the extract of Mentha pulegium plant, a flowering plant in the family of Lamiaceae. The synthesised M-Cu NPs were characterized by advanced technical tools. The maximum absorbance, λmax was found to be 754 nm for M-Cu NPs. The morphological analysis substantiated the spherical shape for NPs with particle size range of 21‒48 nm. The plant extract and synthesised Cu NPs exhibited potential antibacterial activity against the bacterial pathogens, Staphylococcus aureus, Bacillus cereus, Escherichia coli and Klebsiella pneumonia. The maximum zone of inhibition of 12 mm was recorded against B. cereus bacteria. The cell cytotoxicity of M-Cu NPs on normal human lymphocytes was assessed by methylthiazolyldiphenyl-tetrazolium bromide (MTT). M-Cu NPs demonstrated a significant antibacterial activity against S. aureus and B. cereus and almost 98% of normal human peripheral blood cells were found to survive up to 25 μg/mL of M-Cu NPs. [ABSTRACT FROM AUTHOR]

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