Search

Abstract Carbapenem-resistant Klebsiella pneumoniae (CPKP) infections seriously threaten global public health. The main objective of this study was to assess the in-vitro synergistic activity of ceftazidime–avibactam (CZA) in combination with colistin (COL), amikacin (AK), gentamicin (GEN), and fosfomycin (FOS) against CPKP isolates. The secondary goal was to determine the antibiotic susceptibility performance of BD Phoenix. OXA-48 (49.1%) was the predominant carbapenemase, followed by KPC (29.1%). We used the broth microdilution (BMD) method to determine the minimum inhibitory concentrations (MICs) of CZA, COL, AK, and GEN. Meanwhile, the MICs of FOS were determined by the agar dilution (AD) method. To examine the antibacterial activity of CZA, we conducted a checkerboard assay (CBA) with COL, AK, GEN, and FOS against CRKP isolates. We randomly selected three strains and performed synergy testing via time-kill assay (TKA). CRKP isolates were 89.1% susceptible to CZA, 16.4% to COL, 21.8% to GEN, and 29.1% to AK using BMD, 47.3% to FOS by AD. The most synergistic effects were observed in the combination of CZA-COL (78.2%) and CZA-FOS (63.6%). Given the limited therapeutic options for treating severe CRKP infections, combining CZA with COL and FOS may enhance in-vitro activity against clinical CRKP isolates.

Abstract Background Metastatic brain abscesses caused by Klebsiella pneumoniae are extremely rare but life-threatening conditions. To depict a unique case of the middle-aged hypertensive man with an unusual presentation of metastatic brain abscesses originating from a pleural abscess caused by Klebsiella pneumoniae and subsequently leading to loss of consciousness (LOC). Case report A 52-year-old Iranian man with a history of hypertension presented to the emergency department with a five-day history of worsening cough, high-grade fever, shortness of breath, chest pain, fatigue, and a productive cough. Laboratory tests revealed leukocytosis, elevated C-reactive protein, and respiratory alkalosis. A chest computed tomography scan confirmed pneumonia, and a brain scan revealed multiple hypodense lesions. Despite antibiotic therapy, the patient's condition worsened, leading to confusion, disorientation, and loss of consciousness. Magnetic resonance imaging revealed multiple ring-enhancing lesions, suggesting an abscess formation. Bronchial washings and BAL samples confirmed a lower respiratory tract infection. Cultures from the bronchial washings grew Klebsiella pneumoniae. Conclusions Metastatic brain abscesses caused by Klebsiella pneumoniae are exceedingly rare but life-threatening conditions. Timely diagnosis and effective antimicrobial treatment are critical for patient outcomes. This case underscores the significance of recognizing atypical presentations of bacterial infections, as early detection and appropriate management can significantly impact patient outcomes.

Background: Ventilator-associated pneumonia (VAP) in acute respiratory distress syndrome patients is expected in the setting of prolonged mechanical ventilation due to abridged immunity and dysregulation of the microorganisms inhabiting the oral cavity. We conducted this study to identify the spectrum of microorganisms causing VAP in patients admitted to the medicine intensive care unit (MICU) and their antibiotic susceptibility patterns. Materials and Methods: We conducted a retrospective cross-sectional laboratory-based study from January 2021 to April 2021. Our cohort included patients with respiratory distress who were admitted to the MICU. We observed the incidence of VAP and the risk factors responsible for multidrug resistance (MDR) microorganisms in the MICU, along with 250-day survival in the existence of specific comorbidities along with VAP. Results: Clinical charts of patients (n = 366) admitted to the MICU between January 2021 and April 2021 were used. The mean age of patients admitted to MICU was 57.3 ± 18.7 years with a male predominance (n = 252, 68.8%). VAP was diagnosed in 69.1% (n = 253) of patients, and the most common microorganism in our cohort was Klebsiella pneumoniae (n = 78, 30.8%), followed by Acinetobacter spp. (n = 77, 30.4%). None of the K. pneumoniae isolates (n = 0/78) and only a minority of Acinetobacter spp. (n = 4/77, 5.2%) and Pseudomonas aeruginosa isolates (n = 8/54, 14.8%) were susceptible to fluoroquinolones. A higher proportion of K. pneumoniae (n = 1/78, 1.3%), Acinetobacter spp. (n = 2/77, 2.6%), and P. aeruginosa isolates (n = 9/54, 16.7%) were susceptible to aminoglycosides. The incidence rate of MDR microorganisms among the 253 patients diagnosed with VAP was 92.8% (n = 219/253). Conclusion: There is a high prevalence of multidrug resistance (MDR) isolates among those causing VAP in the MICU setting. Knowing the broad spectrum of causative pathogens and their susceptibility to various antibiotics may guide the physician in judicious and appropriate use of antibiotics for treatment.

Abstract Bloodstream infections caused by multidrug-resistant organisms such as Klebsiella pneumoniae are a significant challenge in managing hematological malignancies. This study aims to characterize the epidemiology of Klebsiella pneumoniae bloodstream infections specifically in patients with hematological malignancies, delineate the patterns of initial antibiotic therapy, assess the prevalence of resistant strains, identify risk factors for these resistant strains, and evaluate factors influencing patient outcomes. A retrospective analysis was conducted at a single center from January 2017 to December 2020, focusing on 182 patients with hematological malignancies who developed Klebsiella pneumoniae bloodstream infections. We compared the 30-day mortality rates between patients receiving appropriate and inappropriate antibiotic treatments, including the effectiveness of both single-drug and combination therapies. Kaplan–Meier survival analysis and multivariate logistic and Cox regression were used to identify factors influencing mortality risk. The 30-day all-cause mortality rate was 30.2% for all patients. The 30-day all-cause mortality rates were 77.2% and 8.8% in patients who received inappropriate initial treatment and appropriate initial treatment (p

Background and Aim: One of the most important bacterial resistance mechanisms is production of Extended-Spectrum Beta-Lactamase (ESBL). In addition, ESBL strains usually have resistance to several antibiotic classes, because multiple resistance genes are often carried by a plasmid. One of these multiple resistances is the simultaneous resistance to quinolones and ESBL production. The aim of this study was to determine the prevalence of resistance to fluoroquinolones in ESBL-producing Klebsiella pneumoniae isolates in Sanandaj health centers in 2018. Materials and Methods: Evaluation of antibiotic susceptibility in all isolates (phenotypically and at Minimum inhibitory concentration (MIC) and identification of ESBL strains were performed by VITEK2. We evaluated the relationship between ESBL production and resistance to fluoroquinolones (ciprofloxacin and levofloxacin) by statistical tests. Results: According to the antibiotic susceptibility results of 67 isolates, 35 isolates (52.23%) were resistant to ciprofloxacin and levofloxacin. 25 isolates (37.31%) were identified as ESBL, of which 19 isolates (76%) were resistant to levofloxacin and ciprofloxacin and only 6 isolates (24%) were sensitive to these antibiotics. Statistical analysis showed that resistance to ciprofloxacin and levofloxacin was significantly increased in ESBL isolates compared to that in non-ESBL isolates (P-value = 0.003). Conclusions: In this study, simultaneous resistance to fluoroquinolones (ciprofloxacin and levofloxacin) and ESBL production was observed in Klebsiella pneumoniae isolates, which can limit treatment options. Also, the results of this study showed that the treatment of the ESBL Klebsiella pneumoniae infection with levofloxacin and ciprofloxacin antibiotics will be a challenge in these medical centers.

ObjectiveTo determine the drug sensitivity and molecular typing characteristics of Klebsiella pneumoniae isolated from meat and diarrhea samples in a local area.MethodsSeventy-one strains of K.pneumoniae were isolated from 118 meat food （chicken and pork） randomly sampled in the markets in Jinshan District， Shanghai， 2020‒2021， and 1 499 diarrhea samples from outpatient diarrhoea patients in hospitals in the same district. Then drug susceptibility testing was conducted by micro-broth dilution method， and sequence identity was determined by pulsed field gel electrophoresis（PFGE）.ResultsThe overall detection rate of K.pneumoniae in meat was 11.86% （14/118）， with detection rate 20.93% （9/43） in chicken and 6.67% （5/75） in pork. The difference in detection between meats was statistically significant （χ2=5.317，P

Objective The clinical distribution and drug resistance of Escherichia coli and Klebsiella pneumoniae in a hospital of Nanjing from 2020 to 2022 were analyzed in order to provide the basis for clinical rational use of antibiotics. Methods The distribution and drug resistance of Escherichia coli and Klebsiella pneumoniae specimens in Zhongda Hospital Southeast University from 2020 to 2022 were retrospectively analyzed. Results A total of 3 507, 4 323 and 4 806 pathogenic bacteria were detected from 2020 to 2022. There were 616, 748 and 840 strains of Escherichia coli , and 456, 631 and 757 strains of Klebsiella pneumoniae , with the total 3-year detection rate of 17.4% and 14.6%. There was a statistically significant difference in the constituent ratio of pathogenic bacteria between 2020 and 2022 (P＜0.01). From 2020 to 2022, the top three samples of pathogenic bacteria were sputum, blood and urine. From 2020 to 2022, the drug resistance rates of Escherichia coli to cefepime, ceftriaxone, cefazolin, gentamicin, ciprofloxacin, levofloxacin and compound trimethoprim were significantly different (P＜0.01). The drug resistance rates of Klebsiella pneumoniae to imipenem, ertapenem, cefepime, ceftriaxone, cefoperazone sulbactam, cefazolin, cefoxitin, piperacillin tazobactam, ampicillin, amikacin, gentamicin, levofloxacin, nitrofurantoin and compound trimethoprim were significantly different (P＜0.01). Conclusion The average detection rate of Escherichia coli and Klebsiella pneumoniae was more than 30% in 2020—2022. The resistance of Escherichia coli and Klebsiella pneumoniae to various antibacterial drugs is statistically different. The clinically targeted drugs need to be selected in strict accordance with the drug sensitivity results.

Abstract Current knowledge about effects of disturbance on the fate of invaders in complex microbial ecosystems is still in its infancy. In order to investigate this issue, we compared the fate of Klebsiella pneumoniae (Kp) and Listeria monocytogenes (Lm) in soil microcosms. We then used environmental disturbances (freeze–thaw or heat cycles) to compare the fate of both invaders and manipulate soil microbial diversity. Population dynamics of the two pathogens was assessed over 50 days of invasion while microbial diversity was measured at times 0, 20 and 40 days. The outcome of invasion was strain-dependent and the response of the two invaders to disturbance differed. Resistance to Kp invasion was higher under the conditions where resident microbial diversity was the highest while a significant drop of diversity was linked to a higher persistence. In contrast, Lm faced stronger resistance to invasion in heat-treated microcosms where diversity was the lowest. Our results show that diversity is not a universal proxy of resistance to microbial invasion, indicating the need to properly assess other intrinsic properties of the invader, such as its metabolic repertoire, or the array of interactions between the invader and resident communities.

Background and Aim: Bats are a reservoir for the pathogenic bacteria Klebsiella pneumoniae and can spread it through feces that fall in nests/caves, carried, and dropped while they fly near human settlements, and from their saliva. The emergence and spread of multidrug resistance (MDR) strains of K. pneumoniae indicate that resistant to antibiotics, especially extended-spectrum beta-lactamase (ESBL), is considered an important global health threat. The aim of this study was to determine the presence of the gene encoding extended beta-lactamase in K. pneumoniae isolated from fresh bat feces collected from the Tanjung Ringgit bat cave, East Lombok. Materials and Methods: In this study, 150 fresh fecal samples were analyzed using standard microbiological techniques for the presence of K. pneumoniae. K. pneumoniae-positive isolates were subjected to antibiotic sensitivity testing, followed by molecular detection using polymerase chain reaction. Results: This study showed that 14 (9.3%) of 150 samples were positive for K. pneumoniae. Ten of the 14 samples (71.4%) were MDR isolates and 6 (42.9%) had the blaSHV gene identified. Conclusion: The presence of K. pneumoniae isolated from fresh bat feces, which is MDR and has the blaSHV gene encoding ESBL indicates that bats can be a reservoir for the transmission of MDR and ESBL bacteria has an impact on public health in the study area.

Background and purpose: Due to emerging antibiotic-resistant bacteria, finding effective alternative antimicrobials to combat the bacteria is unavoidable. Bacteriophage therapy as a biologic and highly potentiated therapeutic approach was considered recently. This study aimed to isolate lytic bacteriophage(s) against multi-drug resistant clinical isolates of Klebsiella pneumonia and evaluate the morphological and biological characteristics as candidates for phage therapy. Materials and methods: Obtained clinical isolates from Shahid Madani Hospital in Tabriz, were confirmed as K. pneumoniae, and an antibiotic sensitivity test was performed using the standard disk diffusion method. Then, the isolation of lytic bacteriophages against 16 selected antibiotic-resistant bacterial isolates was carried out. Briefly, samples for phage isolating were gained from sewage water and centrifuged. The supernatant was filtered using a 0.45 µm Filter, mixed with fresh tripton soy broth medium and magnesium sulfate and incubated at room temperature. Then, the solution was mixed with chloroform and evaluation of plaque formation was performed using the agar bilayer technique. Genomes of the bacteriophages were subjected to molecular analysis using Hind III and EcoRV enzymes. Host range determination of the isolated bacteriophages was evaluated using spot test and agar bilayer techniques. Three bacteriophages with a broader host range than others were selected for more characterization. One step growth curve of the phages was drawn and their latent period and burst size were investigated. Then, the stability and survivability of the isolated lytic bacteriophages to different temperatures (-20, 37, 50℃), different rates of pH value (3,4,5,7,9,11,12), and also UV radiation were evaluated. Finally, morphological characteristics of bacteriophage with the broadest host range (PKpMa2/20) were investigated using electron microscopy. Results: 36 clinical bacterial isolates were confirmed as K. pneumoniae based on standard biochemical tests. In the antibiotic susceptibility assay, it was revealed that the highest and lowest rates of antibiotic resistance belonged to cefazoline (80%) and tobramycin (26%) respectively. Isolation of bacteriophages against all 16 selected isolates was successfully performed. After the extraction of the genomes of the phages, a high variety of genome sequences was detected according to molecular analysis. In host range determination, PKpMa2/20 had lytic activity against 11 of 15 isolates. In a study of the one-step growth curve of the phages, with a broader host range than other isolated bacteriophages, latent periods were shown 10, 10, and 15 min and their burst size were 350, 210, and 180 pfu/ml respectively. All of the phages showed appropriate stability in temperatures of -20 and 37 ℃. In the temperature of 50℃, the survivability of PKpMa2/20 was higher than two other phages. Also, PKpMa2/20 was stable in the pH range of 3-12; in the pH value of 3, two other phages stability was ceased but PKpMa2/20 showed appropriate lytic activity. In electron microscopy, PKpMa2/20 had a short tail length of 10 nm and a head with a diameter of about 60 nm that possibly belonged to the family Podoviridae. Conclusion: Based on appropriate lytic effects, latent period, and burst size of the three isolated bacteriophages in the current study, especially PKpMa2/20, and also, their high stability to different temperatures, pH, and UV radiation, they could be considered as candidates for phage therapy to control resistant strains of K. pneumoniae infections but for the therapeutic use of theses phages, more molecular analysis is needed.

Aim: This study aimed to detect the carbapenem resistance of the Klebsiella pneumoniae strains, isolated from clinical specimens with genotypic and phenotypic methods. Material and Methods: A total of 87 Klebsiella pneumoniae strains whose carbapenem resistance was determined by disc diffusion method were included in the study. Carbapenemase was investigated using the combined disk method and polymerase chain reaction (PCR). Results: The evaluation of the PCR results demonstrated that OXA was detected in 60 (68.9%) samples, NDM was detected in 20 (22.9%), OXA + NDM in 5 (5.7%), and KPC was detected in 1 (1.1%) out of 87 clinical samples. Carbapenemase was not detected in one specimen with the PCR method. The results were found compatible with the combined disc test results for all isolates which were detected as only OXA, NDM, and KPC type carbapenemase positive. In 5 (5.7%) strains in which the co-existence of NDM and OXA type carbapenemases was detected by PCR, the combined disc method detected only OXA type carbapenemase. Conclusion: The combined disk method is inadequate in the presence of strains that have multiple carbapenemases, and also have OXA which is the most frequently detected carbapenemase in our hospital. EUCAST recommends verification by other methods in the presence of OXA-48. Genotypic methods can be used for confirmation testing. The detections of strains with NDM, multiple carbapenemases, and the first detection of KPC were striking in the study. Monitoring the spread of these strains in the hospital will be necessary for infection control.

Abstract The emergence of plasmid-mediated tigecycline resistance gene tet(X4) among clinically relevant bacteria has promoted significant concerns, as tigecycline is considered a last-resort drug against serious infections caused by multidrug-resistant bacteria. We herein focused on the isolation and molecular characterization of tet(X4)-positive Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) in wild bird populations with anthropogenic interaction in Faisalabad, Pakistan. A total of 150 birds including black kites (Milvus migrans) and house crows (Corvus splendens) were screened for the presence of tigecycline resistance K. pneumoniae and E. coli. We found two K. pneumoniae and one E. coli isolate carrying tet(X4) originating from black kites. A combination of short- and long-read sequencing strategies showed that tet(X4) was located on a broad host range IncFII plasmid family in K. pneumoniae isolates whereas on an IncFII-IncFIB hybrid plasmid in E. coli. We also found an integrative and conjugative element ICEKp2 in K. pneumoniae isolate KP8336. We demonstrate the first description of tet(X4) gene in the WHO critical-priority pathogen K. pneumoniae among wild birds. The convergence of tet(X4) and virulence associated ICEKp2 in a wild bird with known anthropogenic contact should be further investigated to evaluate the potential epidemiological implications. The potential risk of global transmission of tet(X4)-positive K. pneumoniae and E. coli warrant comprehensive evaluation and emphasizes the need for effective mitigation strategies to reduce anthropogenic-driven dissemination of AMR in the environment.

Abstract Background Klebsiella pneumoniae is a major bacterial and opportunistic human pathogen, increasingly recognized as a healthcare burden globally. The convergence of resistance and virulence in K. pneumoniae strains has led to the formation of hypervirulent and multidrug-resistant strains with dual risk, limiting treatment options. K. pneumoniae clones are known to emerge locally and spread globally. Therefore, an understanding of the dynamics and evolution of the emerging strains in hospitals is warranted to prevent future outbreaks. Methods In this study, we conducted an in-depth genomic analysis on a large-scale collection of 328 multidrug-resistant (MDR) K. pneumoniae strains recovered from 239 patients from a single major hospital in the western coastal city of Jeddah in Saudi Arabia from 2014 through 2022. We employed a broad range of phylogenetic and phylodynamic methods to understand the evolution of the predominant clones on epidemiological time scales, virulence and resistance determinants, and their dynamics. We also integrated the genomic data with detailed electronic health record (EHR) data for the patients to understand the clinical implications of the resistance and virulence of different strains. Results We discovered a diverse population underlying the infections, with most strains belonging to Clonal Complex 14 (CC14) exhibiting dominance. Specifically, we observed the emergence and continuous expansion of strains belonging to the dominant ST2096 in the CC14 clade across hospital wards in recent years. These strains acquired resistance mutations against colistin and extended spectrum β-lactamase (ESBL) and carbapenemase genes, namely bla OXA-48 and bla OXA-232, located on three distinct plasmids, on epidemiological time scales. Strains of ST2096 exhibited a high virulence level with the presence of the siderophore aerobactin (iuc) locus situated on the same mosaic plasmid as the ESBL gene. Integration of ST2096 with EHR data confirmed the significant link between colonization by ST2096 and the diagnosis of sepsis and elevated in-hospital mortality (p-value

Background and objective: Urinary tract infections (UTIs) are the most common bacterial infections where Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the predominating pathogens. These pathogens have a high rate of antibiotic resistance and exhibit the production of extended-spectrum beta-lactamase (ESBL). This study investigated the antibiotic resistance pattern and ESBL production of E. coli and K. pneumoniae isolated from patients with UTIs attending a tertiary care hospital in Nepal by both phenotypic and genotypic techniques. Materials and methods: A cross-sectional study was performed where 4664 mid-stream urine specimens from suspected UTI cases were cultured. Isolated E. coli and K. pneumoniae were subjected to antibiotic susceptibility testing by Kirby Bauer disc diffusion method. Genotypic detection of blaCTX-M gene was performed using polymerase chain reaction (PCR). Results: Out of 4664 urine samples processed, 564 (12.1%) were positive for E. coli (475, 10.2%) and K. pneumonia (89, 1.9%). Out of the total 564 studied samples, 267 (47.3%) were MDR isolates (E. coli: 222, 46.7%; K. pneumoniae: 45, 50.6%) and 96 (17%) were positive for ESBL by double disc confirmatory test. Out of 24 ESBL positive E. coli and 6 K. pneumoniae, 19 (79.2%) and 3 (50%) respectively were positive for blaCTX-M gene. Conclusion: This study indicates high prevalence of MDR and ESBL producing E. coli and K. pneumoniae causing UTIs at an urban hospital setting in Nepal. July 2024; Vol. 18(2):002. DOI: https://doi.org/10.55010/imcjms.18.014 *Correspondence: Gaurab Pandey, Department of Medical Laboratory Science, Nobel College Affiliated to Pokhara University, Kathmandu, Nepal. Email: pandeygaurab67@gmail.com

Summary: Background: Quantitating the contribution of phenotype-responsible elements in hypervirulent Klebsiella pneumoniae is needed. Methods: Isogenic mutants of four hypervirulent clinical isolates that produced K1 (ST23), K2 (ST86), K20 (ST1544), or K54 (ST29) capsules (mean 2.2 log10 LD50 (range 1.5–2.9)) were created to measure the effects on LD50 in a murine model of the hypervirulence-associated plasmid (pVir), iucA, prmpA, prmpA2 (truncated), irp2, and clbBC. Findings: Curing pVir had the greatest increase in survival (mean LD50 to 7.6 (range 7.0–9.0, p ≤ 0.0001), a dosage comparable to classical K. pneumoniae. Results also showed increased mean LD50s for ΔprmpA (5.9, p ≤ 0.0001), ΔiucA (3.6, p ≤ 0.0001), Δirp2 (3.4), ΔrmpAΔiucA (6.3, p ≤ 0.0001), and ΔpVirΔirp2 (8.7, p ≤ 0.0001). Notably ΔpVir had an additional mean LD50 increase of 1.3 compared to the pVir-encoded ΔprmpAΔiucA (p ≤ 0.01), suggesting presence of additional pVir-virulence genes. Truncated pRmpA2 did not contribute to virulence. Odd ratios in the absence of pVir/yersiniabactin, pVir, pRmpA/aerobactin, pRmpA, aerobactin, yersiniabactin, and colibactin demonstrated a 250-fold, 67-fold, 20-fold, 16.7-fold, 9.6-fold, and 1.7-fold decrease in lethality respectively. Interpretation: These data can guide countermeasure development. Funding: This work was supported by NIH R21 AI123558-01 and 1R21AI141826-01A1 (Dr. Russo) and the Department of Veterans Affairs VA Merit Review (I01 BX004677-01) (Dr. Russo). This study was also partially funded by the U.S. Defense Health Program (DHP) Operations and Maintenance.

An agent that contributes to hospital acquired illnesses is Klebsiella pneumoniae. In community-acquired infections and illnesses of the urinary tract, it is the primary and most frequent causal agent. The strains were detected by using Analytical Profile Index (Api-20 E) and 16s rRNA techniques, fifteen trains of K. pneumoniae were obtained from eighteen urine samples collected from patients in Al-Hussein Hospital, Thi-Qar Governorate, Iraq. This research sought to identify the antibiotic resistance of K. pneumoniae to Aztreonam, Ceftriaxone, Trimethoprim, Amikacin, Ciprofloxacin, Meropenem, and Piperacillin, the resistance was high and ranged between (86.6-100)%. The multidrug resistance percentage was 100%, in addition the investigation aimed to detect some virulence genes, (i.e. HtrA and MrkA gene) in K. pneumoniae. The HtrA and MrkA genes were found using the PCR method, which revealed that 6 (40%) of the isolates had the HtrA gene and that all strains under study lacked the MrkA gene.

Purpose Colistin heteroresistance mediates the failure of antibiotic treatments, is prone to lead to colistin resistance, and has been frequently reported in Klebsiella pneumoniae. This study investigated origins of the increase in colistin resistance following colistin exposure to colistin-heteroresistant K. pneumoniae. Methods A modeled colistin-heteroresistant K. pneumoniae strain (i.e., mimicking colistin-heteroresistant [m-CLHR]) was generated using a susceptible K. pneumoniae strain ATCC 10031 and its resistance-induced mutant. Heteroresistance patterns were investigated through population analysis profiling (PAP), competition assays, and fluctuation and stability tests. An in vitro time-killing assay for colistin was performed for the m-CLHR to identify the change in susceptible and resistant populations before and after colistin exposure. Results The generated m-CLHR strain showed a typical heteroresistance pattern for colistin in PAP, and its competition assay did not show fitness costs for any population. The ratio of resistant cells to susceptible cells did not deviate significantly from the range of heteroresistance in the fluctuation test, while the ratios of resistant cells preserved their stability. The in vitro time-killing assay thus showed that the resistant cells increased upon colistin exposure; sequencing analyses confirmed that the surviving resistant cells did not originate from susceptible cells by mutation. This study successfully modeled a colistin-heteroresistant K. pneumoniae strain, i.e., m-CLHR. Conclusion In this modeled heteroresistant strain, only the colistin-resistant population survived the colistin treatment—this suggests that the development of colistin resistance from heteroresistant strain is because of the selection of a resistant population and not by the induction of resistance through mutations in susceptible populations.

SCIENTIFIC RELEVANCE. Pseudomonas aeruginosa is one of the main causative agents of focal and diffuse suppurative inflammations in immunocompromised individuals. The multiple antimicrobial resistance of Р. aeruginosa has created an urgent need to develop effective preventive vaccines against this bacterium and to enhance their protective properties by selecting adjuvants. A promising strategy is to use flagellin, a P. aeruginosa flagellum component inducing the innate immune system through interaction with toll-like receptor 5 (TLR5) and activating the T-cell immune response, as a component or adjuvant in vaccine development.AIM. This study aimed to produce recombinant flagellin C (FliC) of P. aeruginosa and investigate its immunogenicity, adjuvanticity, and protective properties.MATERIALS AND METHODS. The fliC nucleotide sequence was obtained by PCR on template DNA of P. aeruginosa PA-103 and was inserted into the pQE-30 plasmid for subsequent expression in Escherichia coli M15. Recombinant FliC purification involved two stages: isolation of inclusion bodies and their dissolution in buffers containing urea and guanidine hydrochloride. Mice were immunised by two intraperitoneal injections with a two-week interval. The immunisation used purified recombinant FliC at a dose of 50 μg per animal and its combination with the Klebsiella pneumoniae surface antigen in a 1:1 ratio. Serum samples from immunised mice were tested for specific antibodies to recombinant FliC by enzyme-linked immunosorbent assay (ELISA). The protective properties of FliC were assessed by intraperitoneal challenge of mice with cultures of P. aeruginosa PA-103 and K. pneumoniae 204.RESULTS. The authors obtained the producing strain, generated recombinant FliC, and purified the protein to a 97.6% purity. The analysis of serum samples from immunised mice by ELISA and the protection assessment in challenge experiments showed that the purified recombinant FliC protein had immunogenic properties. Furthermore, the experimental challenge of FliC-immunised mice with P. aeruginosa confirmed that recombinant FliC had protective properties, as evidenced by the protection index of 3.0. Recombinant FliC exhibited adjuvant properties, as demonstrated by the effectiveness index of 6.1 observed in the experimental challenge of mice immunised with the combination of recombinant FliC and the surface antigen of K. pneumoniae.CONCLUSIONS. The purified recombinant FliC protein of P. aeruginosa demonstrated protective activity in mice challenged with P. aeruginosa and adjuvant properties when combined with the K. pneumoniae surface antigen, increasing the immunogenicity of the latter. The use of recombinant FliC holds promise for the creation of a candidate vaccine against P. aeruginosa infection.

Abstract Objective Carbapenemase production and biofilm formation in K. pneumoniae are crucial factors influencing the pathogenicity and antibiotic resistance of this bacterium. This study investigated the interplay between carbapenemase production and biofilm formation in K. pneumoniae clinical isolates. Results The distribution of biofilm-forming ability significantly differed between carbapenemase-producing (CP-Kp) (n = 52) isolates and carbapenemase-nonproducing (CN-Kp) isolates (n = 37), suggesting a potential link between carbapenemase production and biofilm formation. All the bla NDM-1-harbouring isolates demonstrated biofilm formation, with varying levels classified as strong (33.33%), moderate (22.22%), or weak (44.45%). bla NDM-1 and bla KPC-coharbouring isolates did not exhibit strong or moderate biofilm formation. bla NDM-1 and bla OXA-48-coharbouring isolates were predominantly moderate (48.65%), followed by weak (32.43%), with none showing strong biofilm production. These findings suggest a correlation between the presence of carbapenemases and biofilm-forming ability; however, the heterogeneity in biofilm-forming abilities associated with different carbapenemase types and the absence of strong biofilm producers in the detected carbapenemase combinations prompt a closer look at the complex regulatory mechanisms governing biofilm formation in CP-Kp isolates.

BACKGROUND: Mycotic aneurysm is a rare entity with rapid progression, which can be fatal without adequate treatment. The incidence of rupture is greater than that of degenerative aneurysms and is associated with a high mortality rate. CASE REPORT: We report the case of a 58-year-old man with a known history of HIV infection with good immunovirological staging, treated squamous cell carcinoma of the anal canal and chronic gastritis, who presented with a six-day history of intense back pain, malaise, fever, and chills. After examination, he was hospitalized with a clinical suspicion of acute pyelonephritis. During hospitalization, he was diagnosed with pneumonia of the right pulmonary base, infectious spondylodiscitis, and mycotic aneurysm of the abdominal aorta, which involved the visceral plaque. The microbiological workup revealed only positive blood cultures for Klebsiella pneumoniae. After a multidisciplinary discussion of the case and six weeks of antibiogram-oriented antibiotic therapy, the patient underwent an aorto-aortic interposition via left thoracophrenolaparotomy without the need to reimplant visceral vessels due to the patch configuration of the proximal anastomosis. The procedure was performed under left heart bypass. The postoperative course was uneventful, and the patient was discharged four weeks later. At 18 months follow-up, she remained asymptomatic and free of recurrence. CONCLUSION: In this case, it remains to be defined whether the cause of the mycotic aneurysm was hematogenous dissemination from the identified pneumonia or contiguity from the diagnosed spondylodiscitis. Given the morbidity and mortality associated with this entity, early diagnosis and adequate treatment with surgical correction and antibiotic therapy with sufficient duration and dose are important aspects for improving survival in these cases.

Aim: Our study aimed to determine the antibiotic resistance rates of K. pneumoniae by retrospectively examining the results of urine culture samples studied in our laboratory. Methods: Urine samples with K. pneumoniae growth, sent to our laboratory from various wards, outpatient clinics, and intensive care units between July 1, 2018 and December 31, 2022 were included in the study and retrospectively examined. Results: The antibiotic to which K. pneumoniae was most resistant was cefixime (53.3%), and the antibiotic to which it was least resistant was imipenem (12.1%). While the lowest resistance rates were observed in the samples of outpatients, the highest resistance rates were observed in the samples of ward patients and to cefixime (81%), amoxicillin clavulanic acid (AMC) (80%), trimethoprim-sulfamethoxazole (TMT/SXT) (74.8%), and ciprofloxacin (72.1%). Ertapenem (48.9%), meropenem (50.2%) and piperacillin-tazobactam (PRP) (57.3%) resistance was found to be higher in intensive care patients. Conclusion: Although fluctuations in resistance rates have been observed over the years, resistance rates have generally been found to be high for antibiotics frequently used in the empirical treatment of urinary tract infections. Re-adjusting treatment according to culture results and keeping resistance rates in mind for empirical treatment will be important for treatment success.

Summary: Background: The current pipeline for new antibiotics fails to fully address the significant threat posed by drug-resistant Gram-negative bacteria that have been identified by the World Health Organization (WHO) as a global health priority. New antibacterials acting through novel mechanisms of action are urgently needed. We aimed to identify new chemical entities (NCEs) with activity against Klebsiella pneumoniae and Acinetobacter baumannii that could be developed into a new treatment for drug-resistant infections. Methods: We developed a high-throughput phenotypic screen and selection cascade for generation of hit compounds active against multidrug-resistant (MDR) strains of K. pneumoniae and A. baumannii. We screened compound libraries selected from the proprietary collections of three pharmaceutical companies that had exited antibacterial drug discovery but continued to accumulate new compounds to their collection. Compounds from two out of three libraries were selected using “eNTRy rules” criteria associated with increased likelihood of intracellular accumulation in Escherichia coli. Findings: We identified 72 compounds with confirmed activity against K. pneumoniae and/or drug-resistant A. baumannii. Two new chemical series with activity against XDR A. baumannii were identified meeting our criteria of potency (EC50 ≤50 μM) and absence of cytotoxicity (HepG2 CC50 ≥100 μM and red blood cell lysis HC50 ≥100 μM). The activity of close analogues of the two chemical series was also determined against A. baumannii clinical isolates. Interpretation: This work provides proof of principle for the screening strategy developed to identify NCEs with antibacterial activity against multidrug-resistant critical priority pathogens such as K. pneumoniae and A. baumannii. The screening and hit selection cascade established here provide an excellent foundation for further screening of new compound libraries to identify high quality starting points for new antibacterial lead generation projects. Funding: BMBF and GARDP.

Abstract Background Klebsiella pneumoniae is a notorious clinical pathogen and frequently carries various plasmids, which are the main carriers of antimicrobial resistance and virulence genes. In comparison to self-transmissible conjugative plasmids, mobilizable plasmids have received much less attention due to their defects in conjugative elements. However, the contribution of mobilizable plasmids to the horizontal transfer of antimicrobial resistance genes and virulence genes of K. pneumoniae remains unclear. In this study, the transfer, stability, and cargo genes of the mobilizable plasmids of K. pneumoniae were examined via genetic experiments and genomic analysis. Methods Carbapenem-resistant (CR) plasmid pHSKP2 and multidrug-resistant (MDR) plasmid pHSKP3 of K. pneumoniae HS11286, virulence plasmid pRJF293 of K. pneumoniae RJF293 were employed in conjugation assays to assess the transfer ability of mobilizable plasmids. Mimic mobilizable plasmids and genetically modified plasmids were constructed to confirm the cotransfer models. The plasmid morphology was evaluated through XbaI and S1 nuclease pulsed-field gel electrophoresis and/or complete genome sequencing. Mobilizable plasmid stability in transconjugants was analyzed via serial passage culture. In addition, in silico genome analysis of 3923 plasmids of 1194 completely sequenced K. pneumoniae was performed to investigate the distribution of the conjugative elements, the cargo genes, and the targets of the CRISPR-Cas system. The mobilizable MDR plasmid and virulence plasmid of K. pneumoniae were investigated, which carry oriT but lack other conjugative elements. Results Our results showed that mobilizable MDR and virulence plasmids carrying oriT but lacking the relaxase gene were able to cotransfer with a helper conjugative CR plasmid across various Klebsiella and Escherichia coli strains. The transfer and stability of mobilizable plasmids rather than conjugative plasmids were not interfered with by the CRISPR–Cas system of recipient strains. According to the in silico analysis, the mobilizable plasmids carry about twenty percent of acquired antimicrobial resistance genes and more than seventy-five percent of virulence genes in K. pneumoniae. Conclusions Our work observed that a mobilizable MDR or virulence plasmid that carries oriT but lacks the relaxase genes transferred with the helper CR conjugative plasmid and mobilizable plasmids escaped from CRISPR–Cas defence and remained stable in recipients. These results highlight the threats of mobilizable plasmids as vital vehicles in the dissemination of antibiotic resistance and virulence genes in K. pneumoniae.

Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, dan Escherichia coli merupakan kelompok critical-priority bacteria yang telah mengalami multi drug resistant (MDR) dan sering ditemukan di Intensive Care Unit (ICU). Isolat bakteri-bakteri berjumlah lebih dari 75% mengalami MDR di ICU sebuah rumah sakit umum daerah di Bali, Indonesia. Penggunaan antibiotik yang tinggi berkaitan dengan tingkat resistensi bakteri terhadap antibiotik. Pola resistensi bakteri terhadap antibiotik dapat berbeda di setiap wilayah yang disebabkan oleh adanya perbedaan lingkungan dan perbedaan tingkat penggunaan antibiotik di wilayah tersebut. Penelitian ini bertujuan untuk mengetahui tren penggunaan antibiotik sistemik, pola resistensi dan hubungan antara tingkat penggunaan dengan persentase resistensi bakteri terhadap antibiotik pada kelompok critical-priority bacteria di ICU rumah sakit “X” provinsi Bali. Penelitian ini merupakan penelitian ekologikal yang menggunakan data sekunder selama tahun 2017-2019. Analisis tren penggunaan antibiotik dianalisis menggunakan time series analysis. Hubungan antara tingkat penggunaan antibiotik dan persentase resistensi bakteri prioritas kritis dianalisis dengan regresi linier. Hasil penelitian menunjukkan bahwa antibiotik gentamisin, amikasin, dan siprofloksasin mengalami peningkatan tren penggunaan sedangkan ampisilin, ampisilin-sulbaktam, seftazidim, dan meropenem mengalami penurunan tren penggunaan. Time series analysis menunjukkan penggunaan antibiotik yang fluktuatif. Selain itu, didapatkan bahwa A. baumannii masuk dalam dua kategori fenotipik CDC yaitu, carbNS_Acine dan MDR_Acine sedangkan K. pneumoniae masuk dalam kategori ESCklebsiella. Tingkat penggunaan antibiotik sistemik di ICU dengan persentase resistensi E. coli, K. pneumoniae, dan P. aeruginosa di ICU (p0,05).

Abstract Objectives This study aimed to evaluate the antibiotic resistance patterns and prevalence of carbapenemase genes in Klebsiella pneumoniae isolates in different clinical samples from Tabriz city, northwestern Iran. Results This cross-sectional study was conducted in the Department of Microbiology, Islamic Azad University, Ahar Branch, Iran, in 2020. K. pneumoniae isolates were collected from different clinical samples, including blood, wounds, sputum, and urine. The isolates were identified using a series of standard bacteriological tests. Antibiotic resistance was determined by the disc diffusion method. The presence of bla VIM, bla NDM, bla KPC, bla OXA, and bla IMP genes were screened by polymerase chain reaction (PCR). A total of 100 non-duplicated K. pneumoniae isolates were collected from 57 urine samples, 27 blood samples, 13 wound samples, and 3 sputum samples. Overall, 70.0% of the samples were from inpatients, while 30.0% were from outpatients. The most resistance rate was related to ampicillin (94.0%), while the lowest resistance rate was related to imipenem (18.0%) and meropenem (20.0%). Overall, 25.0% of the isolates were carbapenem-resistant, of which 13.0% were resistant to both imipenem and meropenem. The PCR showed the total prevalence of 23.0% for carbapenemase genes, including 18.0% for bla KPC, 3.0% for bla VIM, 1.0% for bla IMP, and 1.0% for bla OXA gene. The bla NDM gene was not detected in any isolate. The prevalence of carbapenemase-producing K. pneumoniae isolates was relatively lower in northwestern Iran than in other regions of the country. However, special attention should be paid to the proper use of antibiotics, particularly carbapenems, to prevent further spread of antibiotic resistance and its related genes.

Objective To analyze the clinical distribution of Klebsiella pneumoniae isolates, screen for the multidrug resistance of Klebsiella pneumoniae strains to commonly used antimicrobial drugs, and provide reference for the prevention and control of hospital-acquired infections and rational clinical use of antimicrobial drugs. Methods Various clinical specimens collected from January 2018 to December 2022 at the Zhongda Hospital Affiliated to Southeast University were cultured to isolate bacteria. The VITEK automated microbial analyzer was used to identify the bacterial species. A total of 3 342 non-repetitive Klebsiella pneumoniae isolates were obtained during this period. Each Klebsiella pneumoniae strain was subjected to drug susceptibility testing using automated antimicrobial systems, disk diffusion methods, or standard broth microdilution methods to determine the antibiotic resistance profiles of Klebsiella pneumoniae. The detection rate of Klebsiella pneumoniae in clinical specimens and its association with specimen sources or department categories were analyzed. Results Klebsiella pneumoniae isolates were obtained from sputum (42.07%), urine (14.81%), and blood (10.29%). The departments with higher detection rates of Klebsiella pneumoniae were Intensive Care Unit (ICU) (35.19%), Neurosurgery (6.28%), and Respiratory and Critical Care Medicine (5.42%). The resistance identification results showed the highest resistance rate to ampicillin (100.00%) and the lowest resistance rate to amikacin (4.22%). Annual analysis of resistance rates to carbapenems in Klebsiella pneumoniae isolates from 2018 to 2021 revealed an increasing trend: 2.94%, 4.66%, 7.90%, and 15.35%, respectively. However, in 2022, the resistance rate started to decrease (5.38%). Carbapenem-resistant Klebsiella pneumoniae strains were predominantly of the KPC type, and there was a statistically significant difference in the resistance rates to commonly used antimicrobial drugs between carbapenem-resistant Klebsiella pneumoniae and carbapenem-sensitive Klebsiella pneumoniae(P＜0.01). Conclusion Klebsiella pneumoniae maintains a high level of clinical isolation rate, along with high resistance rates. Therefore, it is necessary to strengthen the prevention and control of hospital-acquired bacterial infections and surveillance of drug resistance. Rational selection of antimicrobial drugs should be employed for the treatment of Klebsiella pneumoniae infections.

Background and Aim: Antibiotic resistance in Klebsiella pneumoniae, especially extended-spectrum beta-lactamase (ESBL) producers, has become a global public health problem. This study aimed to estimate the prevalence of multidrug resistance (MDR) and ESBL-producing K. pneumoniae in wastewater from dairy farms. Materials and Methods: This study was conducted on dairy farms in East Java Province from June to October 2022. In total, 342 dairy farm wastewater samples were isolated on buffered peptone water media from six cities/regencies with the highest dairy cattle population in East Java. Samples were identified using MacConkey agar media, Gram-staining,eosin-methylene blue agar, and biochemical tests. In total, 14.32% (49/342) samples contained K. pneumoniae. Positive isolates were tested for antibiotic sensitivity. Klebsiella pneumoniae resistant to beta-lactam was confirmed using the double-disk synergy test to confirm the presence of ESBL-producing bacteria. Results: The percentage of antibiotic resistance in K. pneumoniae was 98% resistance to ampicillin, 67.3% to cefotaxime, 46.9% to tetracycline, 49% to ciprofloxacin, 98% to streptomycin, 14.3% to sulfamethoxazole–trimethoprim, and 83.7% to chloramphenicol. The prevalence of MDR in K. pneumoniae was 12.57% (43/342), with the highest prevalence in the five classes of antibiotics at 41.86% (18/43), and the prevalence of ESBL-producing K. pneumoniae was 5.55% (19/342), with the highest prevalence in the districts of Blitar and Pasuruan at 26.31% (5/19). Conclusion: Although the prevalence of ESBL-producing K. pneumoniae in wastewater samples from dairy farms was low, caution is recommended because they can be a reservoir for ESBL.

Background: Isolates of Klebsiella pneumoniae resistant to Carbapenem appears to be most commonly transmitted by hospitalized patients. This may cause infections which lead to mortality. Therefore, studies on molecular level will help to gain more information and be able to know their cross-transmission and resistance mechanisms among these isolates showing resistance. Purpose: Investigate the molecular characterization of carbapenem-resistant Klebsiella pneumoniae isolates from various clinical samples. Klebsiella pneumoniae are aerobic and Gram-negative bacilli found in the gastrointestinal tract of humans and other animals and also as saprophytes in soil. Method: In this study, 401 bacteria of Klebsiella isolates were taken from various clinical samples according to standard protocol. Carbapenem-resistant genes of Klebsiella pneumoniae (CRK) isolates were detected using multiplex polymerase chain reaction (PCR). Result: The twelve isolates resistant to carbapenem were confirmed phenotypically and were confirmed using a multiplex Polymerase Chain Reaction. Conclusion: The present study concluded that identification of Carbapenem-resistant genes of Klebsiella pneumoniae (KPC) could help find out the routes of dissemination of the species and may control its spread within the hospital premises.

Background: The CTX-M gene in ESBLs-producing Klebsiella pneumoniae is associated with virulence factors and encodes for antibiotic resistance. There are currently 128 different varieties of CTX-M, which gene can hydrolyze beta-lactam medicines like cefotaxime. Purpose: Identify the CTX-M gene in Klebsiella pneumoniae from patients with Urinary Tract Infections (UTI) at a private hospital in Banyumas Region of Central Java, Indonesia. Method: Cross-sectional survey method was employed in this study. The subjects of the study comprised 40 patients with UTI admitted to a private hospital in Banyumas Region, Central Java, Indonesia. Using a direct molecular approach called Polymerase Chain Reaction (PCR) directed against the CTX-M gene, DNA was isolated from isolates cultured in CHROMagarTM ESBLs obtained from catheter urine samples. Result: A total of 4 out of 40 urine samples (10%) tested positive for ESBL-producing Klebsiella pneumoniae. The PCR was performed to detect the CTX-M gene in 100% of the strains. Conclusion: These findings suggest the presence of CTX-M gene found in ESBLs-producing Klebsiella pneumoniae in individuals with urinary tract infections in a private hospital in Purwokerto, Banyumas regency, Central Java, Indonesia. This information can be used to assess antibiotic administration practices.

In February 2022, a critically ill patient colonized with a carbapenem-resistant K. pneumoniae producing KPC-3 and VIM-1 carbapenemases was hospitalized for SARS-CoV-2 in the intensive care unit of Policlinico Umberto I hospital in Rome, Italy. During 95 days of hospitalization, ceftazidime/avibactam, meropenem/vaborbactam, and cefiderocol were administered consecutively to treat 3 respiratory tract infections sustained by different bacterial agents. Those therapies altered the resistome of K. pneumoniae sequence type 512 colonizing or infecting the patient during the hospitalization period. In vivo evolution of the K. pneumoniae sequence type 512 resistome occurred through plasmid loss, outer membrane porin alteration, and a nonsense mutation in the cirA siderophore gene, resulting in high levels of cefiderocol resistance. Cross-selection can occur between K. pneumoniae and treatments prescribed for other infective agents. K. pneumoniae can stably colonize a patient, and antimicrobial-selective pressure can promote progressive K. pneumoniae resistome evolution, indicating a substantial public health threat.

Prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has compromised antimicrobial efficacy against severe infections worldwide. To monitor global spread, we conducted a comprehensive genomic epidemiologic study comparing sequences from 21 blaOXA-232–carrying CRKP isolates from China with K. pneumoniae sequence type (ST) 15 strains from 68 countries available in GenBank. Phylogenetic and phylogeographic analyses revealed all blaOXA-232–carrying CRKP isolates belonged to ST15 lineage and exhibited multidrug resistance. Analysis grouped 330 global blaOXA-232–carrying ST15 CRKP strains into 5 clades, indicating clonal transmission with small genetic distances among multiple strains. The lineage originated in the United States, then spread to Europe, Asia, Oceania, and Africa. Most recent common ancestor was traced back to 2000; mutations averaged ≈1.7 per year per genome. Our research helps identify key forces driving global spread of blaOXA-232–carrying CRKP ST15 lineage and emphasizes the importance of ongoing surveillance of epidemic CRKP.

INTRODUCTION: The profile of carbapenem-resistant Enterobacterales (CRE), antibiotic susceptibilities were analyzed in our hospital providing a wide range of healthcare services in Southeastern Anatolia. METHODS: This retrospective study included carbapenem-resistant Klebsiella pneumoniae (CRKP, 1022 isolates) and carbapenem-resistant E. coli (CREC, 700 isolates) isolated from patients admitted to xxxxxx Hospital between 2019 and 2022. Isolate typing and antibiotic susceptibility profiles were determined using the BD Phoenix automated system (Becton Dickinson, USA), and the Diagnostics MIC-COL test kit (Diagnostics, Slovakia) was used to determine colistin susceptibility. RESULTS: Out of the total 1022 CRKP isolates, 663 (64.9%) were obtained from intensive care units, 207 (20.2%) from inpatient clinics, and 152 (14.9%) from outpatient clinics. The most sensitive antibiotics for CRKP isolates were found to be ceftazidime-avibactam (CZA) (57%), gentamicin (51%), and amikacin (40%), respectively. Statistically significant changes in susceptibilities to CZA, colistin, trimethoprim-sulfamethoxazole (SXT), tobramycin, meropenem, imipenem, and levofloxacin were observed over the years (p

Controlling the spread of carbapenem-resistant Enterobacterales is a global priority. Using National Healthcare Safety Network data, we characterized the changing epidemiology of carbapenem-resistant Klebsiella pneumoniae (CRKP) in a large public health system in New York, New York, USA. During 2016–2020, CRKP cases declined; however, during 2021–June 2022, a notable increase occurred. Of 509 cases, 262 (51%) were considered community-onset, including 149 in patients who were living at home. Of 182 isolates with proven or presumptive (ceftazidime/avibactam susceptible) enzymes, 143 were serine carbapenemases; most confirmed cases were K. pneumoniae carbapenemase. The remaining 39 cases were proven or presumptive metallo-β-lactamases; all confirmed cases were New Delhi metallo-β-lactamases. After 2020, a marked increase occurred in the percentage of isolates possessing metallo-β-lactamases. Most patients with metallo-β-lactamases originated from long-term care facilities. An aggressive and universal program involving surveillance and isolation will be needed to control the spread of CRKP in the city of New York.

Background: The emergence of coronavirus disease in 2019 (COVID-19) appears to be having an impact on antibiotic resistance patterns. Specific circumstances during the COVID-19 era may have played a role in the spread of antimicrobial resistance (AMR). This study aimed to look at the changes in AMR patterns of Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii at Al-Zahra Hospital. Materials and Methods: From March 2021 to January 2023, 3651 clinical samples were collected from patients hospitalized at Isfahan’s Al-Zahra Hospital. The Clinical and Laboratory Standards Institute recommended procedures for detecting gram-negative bacteria and assessing antibiotic susceptibility were used. We divided the information into three years. Results: Highest resistance rates were seen in A. baumannii to Ciprofloxacin (98.0%) and Ampicillin-Sulbactam (97.0%). For P. aeruginosa the resistance rate for Ceftazidime (36.1), Levofloxacin (37.8), and Meropenem (47.1) dropped seriously in 2022. Conclusion: During the second year of the pandemic in central Iran, all three species studied showed rising rates of AMR. This can be attributable to two peaks within Iran on May 6, 2021 and August 27, 2021. The results of this study show that P. aeruginosa, K. pneumoniae, and A. baumannii bacteria in central Iran have a higher level of antibiotic resistance than previously studied strains before the pandemic.

Background: Deep neck infections (DNIs) can compromise the airway and are associated with high morbidity and mortality rates. Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia that is associated with several comorbidities. We compared the clinical characteristics of DNI patients with and without DM. Methods: This study recorded the relevant clinical variables of 383 patients with DNIs between November 2016 and September 2022; of those patients, 147 (38.38%) had DM. The clinical factors between DNI patients with and without DM were assessed. Results: Patients with DM were older (p < 0.001), had higher white blood cell counts (p = 0.029) and C-reactive protein levels (CRP, p < 0.001), had a greater number of deep neck spaces (p = 0.002) compared to patients without DM, and had longer hospital stays (p < 0.001). Klebsiella pneumoniae was cultured more frequently from patients with DM than those without DM (p = 0.002). A higher CRP level (OR = 1.0094, 95% CI: 1.0047–1.0142, p < 0.001) was a significant independent risk factor for DM patients with prolonged hospitalization. The lengths of hospital stays in patients with poorly controlled DM were longer than those with well-controlled DM (p = 0.027). Conclusions: DNI disease severity and outcomes were worse in patients with DM than those without DM. Antibiotics effective against Klebsiella pneumoniae should be used for DNI patients with DM. DNI patients with DM and high CRP levels had more prolonged hospitalizations. Appropriate blood glucose control is essential for DNI patients with DM.

Background: Klebsiella pneumoniae is a nosocomial pathogen that causes severe infections in immunocompromised patients. The aim of the study was to conduct a microbiological and clinical analysis of K. pneumoniae infections in children with malignancies or undergoing hematopoietic cell transplantation in Poland. Methods: We conducted a retrospective, multicenter study including children and adolescents under 19 years old treated between 2012 and 2021. We analyzed patients’ characteristics, microbiological data, and the outcomes of antibiotic therapy. Results: A total of 9121 newly diagnosed children were treated for malignancy and 1697 pediatric patients underwent hematopoietic cell transplantation. K. pneumoniae infections were diagnosed in 527 patients. Their overall incidence was 4.86% in pediatric hematology and oncology patients and 4.95% in patients who underwent hematopoietic cell transplantation. The incidence of infection was higher in patients with acute leukemia than with solid tumors (7.8% vs. 4.1%; OR = 2.0; 95% CI = 1.6–2.4; p < 0.0001). The most frequent source of infection was in the urinary tract at 55.2%. More than 57% of K. pneumoniae strains were extended-spectrum β-lactamase-positive and almost 34% were multidrug-resistant. Infections with K. pneumoniae contributed to death in 3.22% of patients. Conclusions: K. pneumoniae is one of the most critical pathogens in children suffering from malignancies or undergoing hematopoietic cell transplantation. The incidence of multidrug-resistant K. pneumoniae strains is increasing and contributing to poor clinical outcome.

Summary: Background: The epidemiological features of the Klebsiella pneumoniae causing bloodstream infections in Hong Kong and their potential threats to human health remained unknown. Methods: K. pneumoniae strains collected from four hospitals in Hong Kong during the period of 2009–2018 were subjected to molecular typing, string test, antimicrobial susceptibility testing, whole genome sequencing and analysis. Clinical data of patients from whom these strains were isolated were analyzed retrospectively using univariate and multivariate logistic regression approaches. Findings: The 240 Klebsiella spp. strains belonged to 123 different STs and 63 different capsule loci (KLs), with KL1 and KL2 being the major type. 86 out of 212 BSI-KP (40.6%) carried at least one of the virulence genes iuc, iro, rmpA or rmpA2. Virulence plasmid correlated well with the string test positive result, yet 8 strains without rmp genes were also hypermucoviscous, which was due to wzc mutation. The mortality rate of bloodstream infection patients was 43.0%. Univariant analysis showed that factors including renal replacement therapy (FDR adjusted p = 0.0007), mechanical ventilation (FDR adjusted p

ABSTRACT BACKGROUND: To the best of our knowledge, this is the first study to evaluate the effectiveness of specific concentrations of antibiofilm agents, such as N-acetyl cysteine (NAC), rifampicin, and ozone, for the treatment of pan-resistant Klebsiella pneumoniae (PRKp). OBJECTIVES: We evaluated the effectiveness of antibiofilm agents, such as NAC, rifampicin, and ozone, on biofilm formation in PRKp at 2, 6, 24, and 72 h. DESIGN AND SETTING: This single-center experimental study was conducted on June 15, 2017, and July 15, 2018, at Istanbul Faculty of Medicine, Istanbul University, Turkey. METHODS: Biofilm formation and the efficacy of these agents on the biofilm layer were demonstrated using colony counting and laser-screened confocal microscopy. RESULTS: NAC at a final concentration of 2 μg/mL was administered to bacteria that formed biofilms (24 h), and no significant decrease was detected in the bacterial counts of all isolates (all P > 0.05). Rifampicin with a final concentration of 0.1 μg/mL was administered to bacteria that formed biofilm (24 h), and no significant decrease was detected in bacterial count (all P > 0.05). Notably, ozonated water of even 4.78 mg/L concentration for 72 h decreased the bacterial count by ≥ 2 log10. CONCLUSION: Different approaches are needed for treating PRKp isolates. We demonstrate that PRKp isolates can be successfully treated with higher concentrations of ozone.

Background: Klebsiella oxytoca is a Gram-negative rod-shaped bacterium that is becoming resistant to multiple drugs and is frequently endangering patients' lives. It is a member of the human microbiota. Objectives: To assess the value of identifying K. oxytoca using an automated diagnostic system (VITEK-2) as compared to traditional manual methods. Materials and Methods: A total of 136 clinical specimens were collected from patients in Baghdad hospitals during a period from July to November 2022. VITEK-2 system was used to recognize the isolated bacteria to the genus and species level. The biochemical indole test was used as a confirmatory test at the species level. Results: K. oxytoca was more common in urine samples 49 (36.0%) followed by blood samples 21 (15.4%). Of the total collected samples 77 (56.6%) were from inpatients and (43.3%) were from outpatients. The primary identification by cultural and microscopic examinations diagnosed all the isolates as Klebsiella. VITEK-2 system recognized them as K. pneumoniae. The indole test confirmed the species as K. oxytoca by the formation of the red ring. Conclusion: using a simple biochemical test like indole is crucial in clinical laboratories to investigate the accuracy of bacterial identification at the species level. Continuous evaluation for the identification results of the automated systems is needed and can be done by updating the system software for the new emerging pathogens in the hospitals. Received June. 2022 Accepted Sept. 2023 Published Jan. 2024

Abstract Background Certain clonal complexes (CCs) of Klebsiella pneumoniae such as CC147 (ST147 and ST392) are major drivers of bla NDM dissemination across the world. ST147 has repeatedly reported from our geographical region, but its population dynamics and evolutionary trajectories need to be further studied. Methods Comparative genomic analysis of 51 carbapenem-nonsusceptible strains as well as three hypervirulent K. pneumoniae (hvKp) recovered during 16-months of surveillance was performed using various bioinformatics tools. We investigated the genetic proximity of our ST147 strains with publicly available corresponding genomes deposited globally and from neighbor countries in our geographic region. Results While IncL/M plasmid harboring bla OXA-48 was distributed among divergent clones, bla NDM-1 was circulated by twenty of the 25 CC147 dominant clone and were mostly recovered from the ICU. The NDM-1 core structure was bracketed by a single isoform of mobile genetic elements (MGEs) [ΔISKpn26-NDM-TnAs3-ΔIS3000-Tn5403] and was located on Col440I plasmid in 68.7% of ST392. However, various arrangements of MGEs including MITESen1/MITESen1 composite transposon or combination of MITESen1/ISSen4/IS903B/IS5/ISEhe3 on IncFIb (pB171) were identified in ST147. It seems that ST392 circulated bla NDM-1 in 2018 before being gradually replaced by ST147 from the middle to the end of sample collection in 2019. ST147 strains possessed the highest number of resistance markers and showed high genetic similarity with four public genomes that harbored bla NDM-1 on the same replicon type. Mainly, there was a convergence between clusters and isolated neighboring countries in the minimum-spanning tree. A conserved arrangement of resistance markers/MGEs was linked to methyltransferase armA which was embedded in class 1 integron in 8 isolates of ST147/ST48 high-risk clones. Conclusion Our findings highlight the dynamic nature of bla NDM-1 transmission among K. pneumoniae in Iran that occurs both clonally and horizontally via various combinations of MGEs. This is the first analysis of Iranian ST147/NDM + clone in the global context.

After an increase in carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infections and associated deaths in the neonatal unit of a South Africa hospital, we conducted an outbreak investigation during October 2019–February 2020 and cross-sectional follow-up during March 2020–May 2021. We used genomic and epidemiologic data to reconstruct transmission networks of outbreak-related clones. We documented 31 cases of culture-confirmed CRKP infection and 14 deaths. Two outbreak-related clones (blaNDM-1 sequence type [ST] 152 [n = 16] and blaOXA-181 ST307 [n = 6]) cocirculated. The major clone blaNDM-1 ST152 accounted for 9/14 (64%) deaths. Transmission network analysis identified possible index cases of blaOXA-181 ST307 in October 2019 and blaNDM-1 ST152 in November 2019. During the follow-up period, 11 new cases of CRKP infection were diagnosed; we did not perform genomic analysis. Sustained infection prevention and control measures, adequate staffing, adhering to bed occupancy limits, and antimicrobial stewardship are key interventions to control such outbreaks.

Blood and surveillance cultures from an injured service member from Ukraine grew Acinetobacter baumannii, Klebsiella pneumoniae, Enterococcus faecium, and 3 distinct Pseudomonas aeruginosa strains. Isolates were nonsusceptible to most antibiotics and carried an array of antibiotic resistant genes, including carbapenemases (blaIMP-1, blaNDM-1, blaOXA-23, blaOXA-48, blaOXA-72) and 16S methyltransferases (armA and rmtB4).

Background: Klebsiella pneumoniae is a concerning pathogen, responsible for hospital-associated outbreaks. Multi drug resistant (MDR) strains are especially hard to treat. We conducted whole-genome sequencing on a MDR K. pneumoniae strain in order to identify genomic features potentially linked to its phenotype. Methods: DNA sequencing was performed on the Illumina iSeq 100 platform. Genome assembly was carried out with SPAdes. The genome was annotated with RASTtk. Typing was performed with MLST and Kaptive. Antibiotic resistance genes were detected with AMRFinderPlus and Abricate, and further verified with BLAST. Results: The strain exhibited resistance to ceftazidime/avibactam and cefiderocol, but remained susceptible to carbapenems. The strain belonged to sequence type ST101, serotype O1:K17. The analysis of antibiotic resistance genes indicated that the strain carried a novel KPC variant, designated as KPC-203, featuring a EL deletion at amino acid position 166–167, within the Ω-loop, and a nine-amino-acid insertion (LAVYTRAPM) at position 259. Sequence alterations were found in porin genes ompK35 and ompK36. Unlike molecular testing, which was able to detect the KPC-203 variant, all phenotypic carbapenemase detection methods achieved negative results. Conclusions: KPC-203, a novel KPC variant, showed a sequence modification in a cephalosporin resistance-associated hotspot. Interestingly, such alterations typically correlate with the restoration of carbapenem susceptibility. We hypothesize that KPC-203 likely led to resistance to ceftazidime/avibactam and cefiderocol, while maintaining susceptibility to carbapenems.

Carbapenem antibiotic resistance is an emerging medical concern. Bacteria that possess the Klebsiella pneumoniae carbapenemase (KPC) protein, an enzyme that catalyzes the degradation of carbapenem antibiotics, have exhibited remarkable resistance to traditional and even modern therapeutic approaches. This study aimed to identify potential natural drug candidates sourced from the leaves of Artemisia judaica (A. judaica). The phytoconstituents present in A. judaica dried leaves were extracted using ethanol 80%. A reasonable amount of the extract was used to identify these phytochemicals via gas chromatography/mass spectrometry (GC/MS). One hundred twenty-two bioactive compounds from A. judaica were identified and subjected to docking analysis against the target bacterial protein. Four compounds (PubChem CID: 6917974, 159099, 628694, and 482788) were selected based on favorable docking scores (−9, −7.8, −7.7, and −7.5 kcal/mol). This computational investigation highlights the potential of these four compounds as promising antibacterial candidates against the specific KPC protein. Additionally, in vitro antibacterial assays using A. judaica extracts were conducted. The minimum inhibitory concentration (MIC) against the bacterium K. pneumonia was 125 μg/mL. Well–disk diffusion tests exhibited inhibition zones ranging from 10.3 ± 0.5 mm to 17 ± 0.5 mm at different concentrations, and time–kill kinetics at 12 h indicated effective inhibition of bacterial growth by A. judaica leaf extracts. Our findings have revealed the pharmaceutical potential of Artemisia judaica as a natural source for drug candidates against carbapenem-resistant pathogens.

The World Health Organization (WHO)’s list of neglected tropical diseases (NTDs) highlights conditions that are responsible for devastating health, social and economic consequences, and yet, they are overlooked and poorly resourced. The NTD list does not include conditions caused by Gram-negative bacilli (GNB). Infections due to GNB cause significant morbidity and mortality and are prevalent worldwide. Southeast Asia is a WHO region of low- and middle-income countries carrying the largest burden of NTDs. Two significant health threats in Southeast Asia are Burkholderia pseudomallei (causing melioidosis) and hypervirulent Klebsiella pneumoniae (HvKp). Both diseases have high mortality and increasing prevalence, yet both suffer from a lack of awareness, significant under-resourcing, incomplete epidemiological data, limited diagnostics, and a lack of evidence-based treatment. Emerging evidence shows that both melioidosis and HvKp are spreading globally, including in high-income countries, highlighting the potential future global threat they pose. In this article, we review both conditions, identifying current trends and challenges in Southeast Asia and areas for future research. We also argue that melioidosis and HvKp merit inclusion as NTDs, and that mandatory global surveillance and reporting systems should be established, and we make an urgent call for research to better understand, detect, and treat these neglected diseases.

Background: Increasing prevalence of carbapenem resistance among Enterobacterales, particularly Escherichia coli and Klebsiella pneumoniae, poses a serious public health threat globally. Furthermore, these bacteria exhibit multidrug resistance, making treatment of infections caused by them challenging. Colistin is one of the antibiotics used in the treatment of infections caused by carbapenem resistant Enterobacterales; however, its unrestricted usage has resulted in the emergence of colistin resistant strains. The present study was conducted to determine the prevalence of carbapenem resistance and co-resistance to carbapenem and colistin resistance among E. coli and K. pneumoniae isolated from various clinical specimens from patients attending various departments of a multispecialty teaching hospital in Haryana, India. Methods: A total of 597 isolates comprising 425 E. coli and 172 K. pneumoniae isolated between March 2019 to November 2021 were included in the study. The isolates were subjected to screening for the detection of carbapenemase production using carbapenem discs and a phenotypic test, that is, the CarbaNP test. Antibiogram of the carbapenem-resistant isolates was further analyzed by the Kirby–Bauer disc diffusion method and to evaluate colistin resistance, isolates were subjected to colistin broth disc elution test. Results: The prevalence of carbapenemase production among the E. coli and K. pneumoniae isolates by the screening test were detected to be 98/425 (23.1%) for E. coli and 90/172 (52.3%) for K. pneumoniae, whereas the CarbaNP test confirmed 93/425 (21.9%) and 84/172 (48.8%) of the two categories of bacterial isolates, thus showing a false positivity rate of 2.6% (n = 11) by screening test for the detection of carbapenemase production. Among the bacterial isolates, 3 (1.7%) comprising 1 (1.1%) E. coli and 2 (2.6%) K. pneumoniae were found to be dual carbapenem- and colistin-resistant strains. K. pneumoniae isolates showed higher resistance rates to non-carbapenem antibiotics compared to E. coli isolates. Conclusions: The emergence of bacteria with concurrent resistance to carbapenems and colistin is a serious concern as they are the last-resort drugs against multidrug-resistant and extensively drug-resistant bacteria.

Background and objectives: Fluoroquinolones are a class of broad-spectrum antimicrobials typically used for the treatment of lower urinary tract infections. We aimed to determine the frequency of quinolone resistance genes in Klebsiella pneumoniae isolates from urinary tract infections in Guilan Province, Iran. Methods: The resistance of 114 clinical isolates of K. pneumoniae to common fluoroquinolones and the minimum inhibitory concentration of ciprofloxacin were determined by disk diffusion and broth microdilution methods, respectively. Frequency of five plasmid-mediated quinolone resistance (PMQR) genes including qnrA, qnrB, qnrS, qepA, and aac (6')-Ib-cr was determined by PCR. Results. According to phenotypic assays, 60 isolates (52.6%) were resistant to at least one quinolone compound, 42 isolates (36.8%) were resistant to all tested quinolones, and 28 isolates (24.6%) showed a high level of ciprofloxacin resistance. In addition, aac(6')-Ib-cr was the most common PMQR gene (𝑛 = 44), followed by qnrS (𝑛 = 32), and qnrB (𝑛 = 21). Conclusion: The possible dissemination of PMQR genes poses a serious threat to the management of infections by resistant Klebsiella pneumoniae.

Klebsiella pneumoniae is an important multidrug-resistant (MDR) pathogen that can cause a range of infections in hospitalized patients. With the growing use of antibiotics, MDR K. pneumoniae is more prevalent, posing additional difficulties and obstacles in clinical therapy. To provide a valuable reference to deeply understand K. pneumoniae, and also to provide the theoretical basis for clinical prevention of such bacteria infections, the antibiotic resistance and mechanism of K. pneumoniae are discussed in this article. We conducted a literature review on antibiotic resistance of K. pneumoniae. We ran a thorough literature search of PubMed, Web of Science, and Scopus, among other databases. We also thoroughly searched the literature listed in the papers. We searched all antibiotic resistance mechanisms and genes of seven important antibiotics used to treat K. pneumoniae infections. Antibiotics such as β-lactams, aminoglycosides, and quinolones are used in the treatment of K. pneumoniae infection. With both chromosomal and plasmid-encoded ARGs, this pathogen has diverse resistance genes. Carbapenem resistance genes, enlarged-spectrum β-lactamase genes, and AmpC genes are the most often β-lactamase resistance genes. K. pneumoniae is a major contributor to antibiotic resistance worldwide. Understanding K. pneumoniae antibiotic resistance mechanisms and molecular characteristics will be important for the design of targeted prevention and novel control strategies against this pathogen.

Abstract Background Klebsiella pneumoniae capsular types K1, K2, K5, K20, K54, and K57 are prevalent hypervirulent types associated with community infections, and worrisomely, hypervirulent strains that acquired drug resistance have been found. In the search for alternative therapeutics, studies have been conducted on phages that infect K. pneumoniae K1, K2, K5, and K57-type strains and their phage-encoded depolymerases. However, phages targeting K. pneumoniae K20-type strains and capsule depolymerases capable of digesting K20-type capsules have rarely been reported. In this study, we characterized a phage that can infect K. pneumoniae K20-type strains, phage vB_KpnM‐20. Methods A phage was isolated from sewage water in Taipei, Taiwan, its genome was analyzed, and its predicted capsule depolymerases were expressed and purified. The host specificity and capsule-digesting activity of the capsule depolymerases were determined. The therapeutic effect of the depolymerase targeting K. pneumoniae K20-type strains was analyzed in a mouse infection model. Results The isolated Klebsiella phage, vB_KpnM‐20, infects K. pneumoniae K7, K20, and K27-type strains. Three capsule depolymerases, K7dep, K20dep, and K27dep, encoded by the phage were specific to K7, K20, and K27-type capsules, respectively. K20dep also recognized Escherichia coli K30-type capsule, which is highly similar to K. pneumoniae K20-type. The survival of K. pneumoniae K20-type-infected mice was increased following administration of K20dep. Conclusions The potential of capsule depolymerase K20dep for the treatment of K. pneumoniae infections was revealed using an in vivo infection model. In addition, K7dep, K20dep, and K27dep capsule depolymerases could be used for K. pneumoniae capsular typing.

Objective. Colistin is an antibiotic of last resort for treating serious Gram-negative bacterial infections. However, the misuse of colistin, especially as an animal growth promoter, has contributed to increasing antimicrobial resistance, mediated mainly through plasmid transfer of the mcr-1 gene. This study assessed the prevalence of phenotypic and molecular colistin resistance in Escherichia coli and Klebsiella pneumoniae in Ecuador in healthy humans and their chickens and pigs. Methods. Fecal samples were collected from humans and their chickens and pigs in two rural coastal and Amazon regions between April and August 2020. Gram-negative bacteria were isolated and identified using conventional techniques. Phenotypic resistance was determined using the broth microdilution technique, and the mcr-1 gene was detected using conventional polymerase chain reaction. Results. A total of 438 fecal samples were obtained from 137 humans, 147 pigs and 154 chickens. The prevalence of E. coli isolates was 86.3% (378/438) and K. pneumoniae, 37.4% (164/438). Overall, the mcr-1 gene was found in 90% (340/378) of E. coli isolates, with higher prevalences found in isolates from coastal regions (96.5%, 191/198), humans (95.6%, 111/116) and chickens (91.8%, 123/134); for K. pneumoniae, the gene was found in 19.5% (32/164) of isolates, with equal distribution between regions and hosts. Only four isolates, two E. coli and two K. pneumoniae, showed phenotypic resistance: mcr-1 was present in both E. coli strains but absent in the K. pneumoniae strains. Conclusions. Despite a low prevalence of phenotypic resistance to colistin, the high prevalence of the mcr-1 gene in E. coli is of concern. Ecuador’s ban on using colistin in animal husbandry must be enforced, and continual monitoring of the situation should be implemented.