Virulence factors, antibiotic resistance patterns, and molecular types of clinical isolates of Klebsiella Pneumoniae

Genetic relatedness, antibiotic resistance, and virulence of Klebsiella pneumoniae isolated from health care and food sources in Wuhan, China

BACKGROUND

To investigate genetic relatedness and antibiotic resistance of Klebsiella pneumoniae from retail meat samples, clinical source samples, and hospital environmental samples in Wuhan, China.

METHODS

Hypermucoviscosity and biofilm formation of K. pneumoniae were assessed by string test and crystal violet staining. MICs of 18 antimicrobials were determined by broth microdilution. PCR detected 14 antibiotic resistance genes. Genetic relatedness and clonal dissemination were analyzed by PFGE.

RESULTS

Among 5,730 samples, 46 were tested positive for K pneumoniae, with higher rates observed in meat (23.4%) than in clinical samples (0.6%) and hospital environmental samples (8.0%). Meat-derived isolates showed high resistance to tetracycline (36.4%, 4/11), sulfonamide (27.3%, 3/11), and gentamicin (27.3%, 3/11), whereas clinical isolates exhibited significant resistance to ampicillin-sulbactam (32.3%, 10/31). Multidrug resistance was observed in 17.4% (8/46) of the isolates, particularly in hospital environmental samples (3/4). Biofilm production was observed in 88.1% (37/42) of K pneumoniae. Pulsed-field gel electrophoresis analysis revealed patient-to-patient K pneumoniae transmission, transmission between patients and hospital environment, as well as cross-contamination between markets.

CONCLUSIONS

The findings underscore the importance of comprehensive surveillance, infection control, and judicious antibiotic use in mitigating the impact of K pneumoniae on public health, especially in the food chain and health care settings.

Resistance Pattern of Klebsiella pneumoniae in Aseer Region, Saudi Arabia: A Ten-Year Hospital-Based Study

Background and Objectives: The frequency of multidrug-resistant Klebsiella pneumoniae (MDRKP) has dramatically increased worldwide in recent decades, posing an urgent threat to public health. The aim of this study was to assess the extent of K. pneumoniae in the Aseer region and explore the corresponding antimicrobial resistance profile over the last ten years. Materials and Methods: A record-based retrospective study was conducted in a tertiary hospital during the period of 2013 to 2022. The study targeted laboratory samples taken from patients admitted to the hospital and sent for K. pneumoniae culturing. We included only samples taken from the patient and confirmed by the lab. Data were extracted using a pre-structured data extraction sheet to avoid data-collection bias and confirm the inter-rater precision. Statistical Package for Social Sciences (SPSS) version 26 was employed for statistical analysis. All relationships were tested using Pearson X2 test for categorical data or chi-square for linear trend for resistance rate over years. Results: We obtained 3921 samples of isolated K. pneumoniae out of 28,420 bacterial samples. The isolation rate began at 11.3% in 2013, decreased to 6.1% in 2016, and then increased to a peak of 16.3% in 2021, before slightly decreasing to 12.8% in 2022. In total, 23.7% of K. pneumoniae samples were identified in urine samples, 19% in sputum samples, 14% in wound samples, and 11.7% in blood samples. The overall antibiotic resistance rate of K. pneumoniae from 2013 to 2022 showed a significant increase, particularly during 2020 and 2021, before decreasing again in 2022. The resistance rate decreased from 22.2% in 2013 to 18.6% in 2016 and increased to 54.6% and 56.4% during 2020 and 2021, respectively (p = 0.039). Conclusions: We observed a significant shift in K. pneumoniae resistance for some antibiotics during the study period, highlighting the urgent need for enhanced antimicrobial stewardship and infection-control measures.

Respiratory tract infections: an update on the complexity of bacterial diversity, therapeutic interventions and breakthroughs

Respiratory tract infections (RTIs) have a significant impact on global health, especially among children and the elderly. The key bacterial pathogens Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, Staphylococcus aureus and non-fermenting Gram Negative bacteria such as Acinetobacter baumannii and Pseudomonas aeruginosa are most commonly associated with RTIs. These bacterial pathogens have evolved a diverse array of resistance mechanisms through horizontal gene transfer, often mediated by mobile genetic elements and environmental acquisition. Treatment failures are primarily due to antimicrobial resistance and inadequate bacterial engagement, which necessitates the development of alternative treatment strategies. To overcome this, our review mainly focuses on different virulence mechanisms and their resulting pathogenicity, highlighting different therapeutic interventions to combat resistance. To prevent the antimicrobial resistance crisis, we also focused on leveraging the application of artificial intelligence and machine learning to manage RTIs. Integrative approaches combining mechanistic insights are crucial for addressing the global challenge of antimicrobial resistance in respiratory infections.

Protein function annotation and virulence factor identification of Klebsiella pneumoniae genome by multiple machine learning models

Klebsiella pneumoniae is a type of Gram-negative bacterium which can cause a range of infections in human. In recent years, an increasing number of strains of K. pneumoniae resistant to multiple antibiotics have emerged, posing a significant threat to public health. The protein function of this bacterium is not well known, thus a systematic investigation of K. pneumoniae proteome is in urgent need. In this study, the protein functions of this bacteria were re-annotated, and their function groups were analyzed. Moreover, three machine learning models were built to identify novel virulence factors. Results showed that the functions of 16 uncharacterized proteins were first annotated by sequence alignment. In addition, K. pneumoniae proteins share a high proportion of homology with Haemophilus influenzae and a low homology proportion with Chlamydia pneumoniae. By sequence analysis, 10 proteins were identified as potential drug targets for this bacterium. Our model achieved a high accuracy of 0.901 in the benchmark dataset. By applying our models to K. pneumoniae, we identified 39 virulence factors in this pathogen. Our findings could provide novel clues for the treatment of K. pneumoniae infection.

Urinary Tract Infections with Carbapenem-Resistant Klebsiella pneumoniae in a Urology Clinic-A Case-Control Study

BACKGROUND

The aim of our study was to analyze the factors associated with the increased risk of urinary tract infection (UTI) with carbapenem-resistant (CR) Klebsiella pneumoniae (Kpn) and the antibiotic resistance spectrum of the strains in patients. As secondary objectives, we elaborated the profile of these patients and the incidence of different types of carbapenemases.

METHODS

We conducted a retrospective case-control study in which we compared a group of 62 patients with urinary tract infections with CR Kpn with a control group consisting of 136 patients with urinary tract infections with multidrug-resistant (MDR), but carbapenem-sensitive (CS), Kpn, who were hospitalized between 1 January 2022 and 31 March 2024.

RESULTS

Compared to patients with urinary tract infections with CS Kpn, patients with urinary tract infections with CR Kpn were preponderant in rural areas (62.9% vs. 47.1%, p = 0.038) and more frequently had an upper urinary tract infection (69.4% vs. 36.8%, p < 0.01). Among the risk factors examined, patients in the study group had a higher presence of urinary catheters inserted for up to one month (50% vs. 34.6%, p = 0.03), rate of hospitalization in the last 180 days (96.8% vs. 69.9%, p < 0.01) and incidence of antibiotic therapy in the last 180 days (100% vs. 64.7%, p < 0.01). They also had a higher rate of carbapenem treatment in the last 180 days (8.1% vs. 0%, p < 0.01). Patients in the study group had a broader spectrum of resistance to all antibiotics tested (p < 0.01), with the exception of sulfamethoxazole-trimethoprim, where the resistance rate was similar in both groups (80.6% vs. 67.6%, p = 0.059). In the multivariate analysis, transfer from other hospitals (OR = 3.51, 95% and CI: 1.430-8.629) and treatment with carbapenems in the last 180 days (OR = 11.779 and 95% CI: 1.274-108.952) were factors associated with an increased risk of disease compared to the control group. The presence of carbapenemases was observed in all patients with CR Kpn, in the order of frequency New Delhi metallo-ß-lactamase (NDM) (52.2%), Klebsiella pneumoniae carbapenemase (KPC) (32.6%), and carbapenem-hydrolyzing oxacillinase (Oxa-48) (15.2%).

CONCLUSIONS

The environment of origin and previous treatment with carbapenems appear to be the factors associated with an increased risk of urinary tract infection with CR Kpn compared to patients with urinary tract infections with CS Kpn. CR Kpn exhibits a broad spectrum of antibiotic resistance, among which is resistance to carbapenem antibiotics.

Infrared spectroscopy-based machine learning algorithms for rapid detection of Klebsiella pneumoniae isolated directly from patients' urine and determining its susceptibility to antibiotics

Among the most prevalent and detrimental bacteria causing urinary tract infections (UTIs) is Klebsiella (K.) pneumoniae. A rapid determination of its antibiotic susceptibility can enhance patient treatment and mitigate the spread of resistant strains. In this study, we assessed the viability of using infrared spectroscopy-based machine learning as a rapid and precise approach for detecting K. pneumoniae bacteria and determining its susceptibility to various antibiotics directly from a patient's urine sample. In this study, 2333 bacterial samples, including 636 K. pneumoniae were investigated using infrared micro-spectroscopy. The obtained spectra (27996spectra) were analyzed with XGBoost classifier, achieving a success rate exceeding 95 % for identifying K. pneumoniae. Moreover, this method allows for the simultaneous determination of K. pneumoniae susceptibility to various antibiotics with sensitivities ranging between 74 % and 81 % within approximately 40 min after receiving the patient's urine sample.

Molecular characterization of hypermucoviscous carbapenemase-encoding Klebsiella pneumoniae isolates from an Egyptian hospital

This study aimed to screen antibiotic resistance and virulence genes in carbapenem-resistant hypermucoviscous Klebsiella pneumoniae isolates from an Egyptian hospital. Among 38 previously confirmed carbapenem-nonsusceptible K. pneumoniae isolates, a string test identified three isolates as positive for hypermucoviscosity. Phenotypic characterization and molecular detection of carbapenemase- and virulence-encoding genes were performed. PCR-based multilocus sequence typing and phylogenetics were used to determine the clonality and global epidemiology of the strains. The coexistence of virulence and resistance genes in the isolates was analyzed statistically using a chi-square test. Three isolates showed the presence of carbapenemase-encoding genes (blaNDM, blaVIM, and blaIMP), adhesion genes (fim-H-1 and mrkD), and siderophore genes (entB); the isolates belonged to sequence types (STs) 101, 1310, and 1626. The relatedness between these sequence types and the sequence types of globally detected hypermucoviscous K. pneumoniae that also harbor carbapenemases was determined. Our analysis showed that the resistance and virulence profiles were not homogenous. Phylogenetically, different clones clustered together. There was no significant association between the presence of resistance and virulence genes in the isolates. There is a need for periodic surveillance of the healthcare settings in Egypt and globally to understand the true epidemiology of carbapenem-resistant, hypermucoviscous K. pneumoniae.

Antibacterial and antibiofilm effects of green synthesized selenium nanoparticles on clinical Klebsiella pneumoniae isolates

Nanotechnology covers many disciplines, including the biological sciences. In this study, selenium nanoparticles (Se-NPs) were synthesized using Artemisia annua extract and investigated against clinical strains of klebsiella pneumoniae (K. pneumoniae) for their anti-biofilm effects. In this experimental study, from May 1998 to September 1998, 50 clinical samples of blood, urine, and sputum were collected, and K. pneumoniae strains were isolated using microbiological methods. Subsequently, the antibacterial effects of Se-NPs at concentrations of 12-25-50-100/5-6/3-25/125 μg/mL were studied. Finally, biofilm-producing strains were isolated, and the expression of mrkA biofilm gene was studied in real-time strains treated with Se-NPs using real-time polymerase chain reaction (PCR). Out of 50 clinical samples, 20 strains of K. pneumoniae were isolated. Minimum inhibitory concentration (MIC) results of Se-NPs showed that Se-NPs were capable of significant cell killing. Real-time PCR results also showed that mrkA gene expression was significantly reduced in strains treated with Se-NPs. According to this study, Se-NPs could reduce bacterial growth and biofilm formation, therefore, could be considered a candidate drug in the medical application for infections caused by K. pneumoniae.

Virulence factors in carbapenem-resistant hypervirulent Klebsiella pneumoniae

Hypervirulence and carbapenem-resistant have emerged as two distinct evolutionary pathotypes of Klebsiella pneumoniae, with both reaching their epidemic success and posing a great threat to public health. However, as the boundaries separating these two pathotypes fade, we assist a worrisome convergence in certain high-risk clones, causing hospital outbreaks and challenging every therapeutic option available. To better understand the basic biology of these pathogens, this review aimed to describe the virulence factors and their distribution worldwide among carbapenem-resistant highly virulent or hypervirulent K. pneumoniae strains, as well as to understand the interplay of these virulence strains with the carbapenemase produced and the sequence type of such strains. As we witness a shift in healthcare settings where carbapenem-resistant highly virulent or hypervirulent K. pneumoniae are beginning to emerge and replace classical K. pneumoniae strains, a better understanding of these strains is urgently needed for immediate and appropriate response.

Phenotypic and genetic characterization of hypervirulent Klebsiella pneumoniae in patients with liver abscess and ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) and pyogenic liver abscess (PLA) due to Klebsiella pneumoniae infection can trigger life-threatening malignant consequences, however, there are few studies on the strain-associated clinical pathogenic mechanisms between VAP and PLA. A total of 266 patients consist of 129 VAP and 137 PLA were included for analysis in this study. We conducted a comprehensive survey for the two groups of K. pneumoniae isolates, including phenotypic experiments, clinical epidemiology, genomic analysis, and instrumental analysis, i.e., to obtain the genomic differential profile of K. pneumoniae strains responsible for two distinct infection outcomes. We found that PLA group had a propensity for specific underlying diseases, especially diabetes and cholelithiasis. The resistance level of VAP was significantly higher than that of PLA (78.57% vs. 36%, P < 0.001), while the virulence results were opposite. There were also some differences in key signaling pathways of biochemical processes between the two groups. The combination of iucA, rmpA, hypermucoviscous phenotype, and ST23 presented in K. pneumoniae infection is more important and highly prudent for timely treatment. The present study may contribute a benchmark for the K. pneumoniae clinical screening, epidemiological surveillance, and effective therapeutic strategies.

The Biological and Regulatory Role of Type VI Secretion System of Klebsiella pneumoniae

Bacteria communicate with their surroundings through diverse secretory systems, and the recently discovered Type VI Secretion System (T6SS) has gained significant attention. Klebsiella pneumoniae (K. pneumoniae), an opportunistic pathogen known for causing severe infections in both hospital and animal settings, possesses this intriguing T6SS. This system equips K. pneumoniae with a formidable armory of protein-based weaponry, enabling the delivery of toxins into neighboring cells, thus granting a substantial competitive advantage. Remarkably, the T6SS has also been associated with K. pneumoniae's ability to form biofilms and acquire resistance against antibiotics. However, the precise effects of the T6SS on K. pneumoniae's functions remain inadequately studied, despite research efforts to understand the intricacies of these mechanisms. This comprehensive review aims to provide an overview of the current knowledge regarding the biological functions and regulatory mechanisms of the T6SS in K. pneumoniae.

Risk Factors and Mortality of Elderly Patients with Hospital-Acquired Pneumonia of Carbapenem-Resistant Klebsiella pneumoniae Infection

Purpose

Hospital-acquired pneumonia (HAP) caused by carbapenem-resistant K. pneumoniae (CRKP), especially in elderly patients, results in high morbidity and mortality. Studies on risk factors, mortality, and antimicrobial susceptibility of CRKP pulmonary infection among elderly patients are lacking.

Patients and Methods

A retrospective case-control study was conducted from January 2019 to December 2021. The elderly inpatients (≥65 years) who were diagnosed with HAP caused by K. pneumoniae were enrolled. Clinical data were collected. Univariate and multivariate logistic regression analyses were used to identify risk factors. Propensity score matching was used to minimize the effect of potential confounding variables. Kaplan-Meier analysis was used to compare survival.

Results

A total of 115 patients with CRKP infection and 78 patients with carbapenem-susceptible K. pneumoniae (CSKP) infection were recruited. There were four independent risk factors for CRKP infection: history of intensive care unit (ICU) stays from hospital admission to positive respiratory specimen culture for K. pneumoniae (odds ratio (OR)=2.530), Charlson comorbidity index score ≥3 (OR = 2.420), prior exposure to carbapenems (OR = 5.280), and prior K. pneumoniae infection or colonization in the preceding 3 years (OR = 18.529). The all-cause 30-day mortality was 22.3%, the mortality of CRKP and CSKP infection was 28.7% and 12.8%, respectively. Independent risk factors for mortality included: older age (OR = 1.107), immunocompromised patients (OR = 8.632), severe pneumonia (OR = 51.244), quick Sepsis-related Organ Failure Assessment (qSOFA) score ≥2 (OR = 6.187), exposure to tigecycline before infection (OR = 24.702), and prolonged ICU stay (OR = 0.987). Thirty-day mortality was significantly lower in patients receiving ceftazidime-avibactam (CAZ-AVI) containing regimens than patients receiving polymyxin B sulfate (PB) containing regimens (P = 0.048). qSOFA score had a good prognostic effect [area under receiver operating characteristic curve (AUROC) of 0.838].

Conclusion

Active screening of CRKP for the high-risk populations, especially elderly patients, is significant for early detection and successful management of CRKP infection.

First Emergence of NDM-5 and OqxAB Efflux Pumps Among Multidrug-Resistant Klebsiella pneumoniae Isolated from Pediatric Patients in Assiut, Egypt

Introduction

New Delhi metallo-β-lactamase (NDM)-producing K. pneumoniae poses a high risk, especially among Egyptian pediatric patients who consume carbapenems antibiotics very widely and without adequate diagnostic sources. In addition, presence of efflux pump genes such as OqxAB increases resistance against many groups of antimicrobials which exacerbates the problem faced for human health. This study aimed to determine NDM variants among K. pneumoniae strains isolated from pediatric patients in Egypt, analyze the presence of OqxAB genes, and molecular characterization of blaNDM-5-positive K. pneumoniae.

Methods

Fifty-six K. pneumoniae isolates were recovered from pediatric patients, and tested for carbapenemase by modified carbapenem inactivation methods (mCIM) test. Minimum inhibitory concentrations of meropenem and colistin were determined by meropenem E-test strips and broth microdilution, respectively. PCR was used for the detection of the resistant genes (ESBL gene (blaCTX-M), carbapenemase genes (blaNDM, blaKPC) colistin resistant (mcr1, mcr2)) and genes for efflux pump (oqxA and oqxB). BlaNDM was sequenced. The effect of efflux pump in NDM-5-producing isolates was assessed by measuring MIC of ciprofloxacin and meropenem before and after exposure to the carbonyl cyanide 3-chlorophenylhydrazone (CCCP). The horizontal gene transfer ability of blaNDM-5 was determined using liquid mating assay and PCR-based replicon typing (PBRT) was done to determine the major plasmid incompatibility group.

Results

Twenty-nine isolates were positive for blaNDM-1, nine isolates were positive for blaNDM-5, and 15 isolates were positive for blaKPC. There is a significant increase of meropenem MIC of NDM-5-positive isolates compared with NDM-1-positive isolates. In addition, 38 isolates were positive for CTX-M, and 15 isolates were positive for mcr1. Both OqxA and OqxB were detected in 26 isolates and 13 isolates were positive for OqxA while 11 isolates were positive for OqxB only. All NDM-5-producing isolates except one isolate could transfer their plasmids by conjugation to their corresponding transconjugants (E. coli J53). Plasmid replicon typing showed that FII was predominant in NDM-5-producing K. pneumoniae. Similar strains were found between the three isolates and similarity was also detected between the two isolates.

Conclusion

The highly resistant K. pneumoniae producing blaNDM-5 type was firstly isolated from pediatric patients. The association of efflux pump genes such as OqxAB is involved in resistance to ciprofloxacin. This highlighted the severity risk of blaNDM-5-positive K. pneumonia as it could transfer blaNDM-5 to other bacteria and has more resistance against carbapenems. This underlines the importance of continuous monitoring of infection control guidelines, and the urgent need for a national antimicrobial stewardship plan in Egyptian hospitals.

Hypervirulent Klebsiella pneumoniae detection methods: a minireview

Hypervirulent Klebsiella pneumoniae (hvKp), characterized by high virulence and epidemic potential, has become a global public health challenge. Therefore, improving the identification of hvKp and enabling earlier and faster detection in the community to support subsequent effective treatment and prevention of hvKp are an urgent issue. To address these issues, a number of assays have emerged, such as String test, Galleria mellonella infection test, PCR, isothermal exponential amplification, and so on. In this paper, we have collected articles on the detection methods of hvKp and conducted a retrospective review based on two aspects: traditional detection technology and biomarker-based detection technology. We summarize the advantages and limitations of these detection methods and discuss the challenges as well as future directions, hoping to provide new insights and references for the rapid detection of hvKp in the future. The aim of this study is to focus on the research papers related to Hypervirulent Klebsiella pneumoniae involving the period from 2012 to 2022. We conducted searches using the keywords "Hypervirulent Klebsiella pneumoniae, biomarkers, detection techniques" on ScienceDirect and Google Scholar. Additionally, we also searched on PubMed, using MeSH terms associated with the keywords (such as Klebsiella pneumoniae, Klebsiella Infections, Virulence, Biomarkers, diagnosis, etc.).

Analysis of an IncR plasmid carried by carbapenem-resistant Klebsiella pneumoniae: A survey of swine Klebsiella pneumoniae in Jilin Province

OBJECTIVES

This study was conducted in Jilin Province to investigate the mechanism involved in the antibiotic resistance and pathogenicity of Klebsiella pneumoniae.

METHODS

Lung samples were collected from large-scale pig farms in Jilin Province. Antimicrobial susceptibility and mouse lethality assays were carried out. K. pneumoniae isolate JP20, with high virulence and antibiotic resistance, was chosen for whole-genome sequencing. The complete sequence of its genome was annotated, and the virulence and antibiotic resistance mechanism were analysed.

RESULTS

A total of 32 K. pneumoniae strains were isolated and tested for antibiotic resistance and pathogenicity. Among them, the JP20 strain showed high levels of resistance to all tested antimicrobial agents and strong pathogenicity in mice (lethal dose of 1.35 × 1011 CFU/mL). Sequencing of the multidrug-resistant and highly virulent K. pneumoniae JP20 strain revealed that the antibiotic resistance genes were mainly carried by an IncR plasmid. We speculate that extended-spectrum β-lactamases and loss of outer membrane porin OmpK36 play an important role in carbapenem antibiotic resistance. This plasmid contains a mosaic structure consisting of a large number of mobile elements.

CONCLUSION

Through genome-wide analysis, we found that an lncR plasmid carried by the JP20 strain may have evolved in pig farms, possibly leading to multidrug resistance in the JP20 strain. It is speculated that the antibiotic resistance of K. pneumoniae in pig farms is mainly mediated by mobile elements (insertion sequences, transposons, and plasmids). These data provide a basis for monitoring the antibiotic resistance of K. pneumoniae and lay a foundation for an improved understanding of the genomic characteristics and antibiotic resistance mechanism of K. pneumoniae.

Evaluation of polymyxin B AUC/MIC ratio for dose optimization in patients with carbapenem-resistant Klebsiella pneumoniae infection

Polymyxin B has been used as a last-line therapy for the treatment of carbapenem-resistant gram-negative bacterial infection. The pharmacokinetic/pharmacodynamic index (AUC/MIC) of polymyxin B has not been clinically evaluated, given that the broth microdilution method for polymyxin susceptibility testing is rarely used in hospitals. This study analyzed data from 77 patients with carbapenem-resistant Klebsiella pneumoniae infections. Among the samples, 63 K. pneumoniae isolates had MIC values of 1.0 mg/L as measured by broth microdilution but 0.5 mg/L as measured using the Vitek 2 system. Polymyxin B AUC/MIC was significantly associated with clinical response (p = 0.002) but not with 30-day all-cause mortality (p = 0.054). With a target AUC/MIC value of 50, Monte Carlo simulations showed that a fixed dose of 100 mg/12 h and three weight-based regimens (1.25 mg/kg/12 h for 80 kg and 1.5 mg/kg/12 h for 70 kg/80 kg) achieved a cumulative fraction of response >90% regardless of renal function, but the risk of nephrotoxicity was high. For patients with carbapenem-resistant K. pneumoniae infections, the underestimation of polymyxin resistance in automated systems need to be taken into account when optimizing polymyxin B dosing based on pharmacokinetic/pharmacodynamic principles.

Crippling of Klebsiella pneumoniae virulence by metformin, N-acetylcysteine and secnidazole

INTRODUCTION

The emergence of multidrug-resistant Klebsiella pneumoniae in hospitals represents a serious threat to public health. Infections caused by Klebsiella pneumoniae are widespread in healthcare institutions, mainly pneumonia, bloodstream infections, and infections affecting neonates in intensive care units; so, it is necessary to combat this pathogen with new strategies. Targeting virulence factors necessary to induce host damage and disease is a new paradigm for antimicrobial therapy with several potential benefits that could lead to decreased resistance.

BACKGROUND

The influence of metformin, N-acetylcysteine, and secnidazole on Klebsiella pneumoniae virulence factors production was tested. The production of Klebsiella pneumoniae virulence factors such as biofilm formation, urease, proteases, hemolysins, and tolerance to oxidative stress was evaluated phenotypically using sub-inhibitory concentration (1/8 MIC) of metformin, N-acetylcysteine, and secnidazole. For more confirmation, qRT-PCR was used to assess the relative expression level of rmpA, wcaG, fimH-1, mrkD, ureA, and khe genes regulating virulence factors production.

RESULTS

Metformin, N-acetylcysteine, and secnidazole were all found to have a powerful inhibitory effect on the production of virulence factors phenotypically. Our results showed a significant reduction in the expression level of rmpA, wcaG, fimH-1, mrkD, ureA, and khe genes. Furthermore, the tested drugs were investigated in vivo to inform their ability to protect mice against Klebsiella pneumoniae pathogenesis.

CONCLUSIONS

Metformin, N-acetylcysteine, and secnidazole inhibited the virulence of Klebsiella pneumoniae. Besides combating resistant Klebsiella pneumoniae, the tested drugs could also serve as an adjuvant to traditional antibiotics.

Testing the mutant selection window hypothesis with meropenem: In vitro model study with OXA-48-producing Klebsiella pneumoniae

OXA-48 carbapenemases are frequently expressed by Klebsiella pneumoniae clinical isolates; they decrease the effectiveness of carbapenem therapy, particularly with meropenem. Among these isolates, meropenem-susceptible carbapenemase-producers may show decreased meropenem effectiveness. However, the probability of the emergence of resistance in susceptible carbapenemase-producing isolates and its dependence on specific K. pneumoniae meropenem MICs is not completely known. It is also not completely clear what resistance patterns will be exhibited by these bacteria exposed to meropenem, if they would follow the patterns of non-beta-lactamase-producing bacteria and other than beta-lactams antibiotics. These issues might be clarified if patterns of meropenem resistance related to the mutant selection window (MSW) hypothesis. To test the applicability of the MSW hypothesis to meropenem, OXA-48-carbapenemase-producing K. pneumoniae clinical isolates with MICs in a 64-fold range (from susceptible to resistant) were exposed to meropenem in a hollow-fiber infection model; epithelial lining fluid meropenem pharmacokinetics were simulated following administration of 2 grams every 8 hours in a 3-hour infusion. Strong bell-shaped relationships between the meropenem daily dose infused to the model as related to the specific isolate MIC and both the antimicrobial effect and the emergence of resistance were observed. The applicability of the MSW hypothesis to meropenem and carbapenemase producing K. pneumoniae was confirmed. Low meropenem efficacy indicates very careful prescribing of meropenem to treat K. pneumoniae infections when the causative isolate is confirmed as an OXA-48-carbapenemase producer.

Clinical Characteristics and Prognosis of Hospital-Acquired Klebsiella pneumoniae Bacteremic Pneumonia versus Escherichia coli Bacteremic Pneumonia: A Retrospective Comparative Study

Objective

This research aimed to investigate the variations in clinical features and prognosis of HABP caused by E. coli and K. pneumoniae. We also aimed to evaluate the risk variables related to 30-day death in the investigated groups.

Methods

A single-center retrospective cohort research lasting four years was performed. A total of 117 patients with HABP were involved in this research. The primary prognosis was 30-day death.

Results

Among 117 patients with HABP, 60 patients were infected with K. pneumoniae (KP-HABP), and 57 patients were infected with E. coli (E. coli-HABP). A higher proportion of males, ICU admission, undergoing tracheotomy and trachea cannulation, carbapenem-resistant strains, inappropriate empirical therapy (IET), immune compromise, diabetes mellitus, and sepsis were observed in the patients with KP-HABP (all P < 0.05). Meanwhile, the median SOFA score and Pitt score were significantly (P < 0.001) higher in the KP-HABP group compared to the E. coli-HABP group. The 30-day death was 48.33% in the KP-HABP group and 24.56% in the E. coli-HABP group (P = 0.008). After adjusting for the main covariates, the hazard ratios for 30-day mortality in KP-HABP were 1.58 (95% CI:0.80-3.12), 3.24 (95% CI:1.48-7.06), 5.67 (95% CI:2.00-16.07), and 5.99 (95% CI:2.10-17.06), respectively. Multivariate logistic regression models revealed that IET, hypoproteinaemia, cerebral vascular disease (CVD), and SOFA score ≥ 5.0 were the independent risk variables for 30-day death in KP-HABP. Simultaneously, SOFA score ≥ 4.0 and Pitt score ≥ 2.0 were independent risk factors for 30-day mortality in E. coli-HABP.

Conclusion

The clinical features of HABP vary depending on whether it is caused by Escherichia coli or K. pneumoniae. KP-HABP patients have higher 30-day mortality than E. coli-HABP patients. To ensure greater validity, it is necessary to further verify this conclusion using a larger sample size.

Bacterial Etiology of Urinary Tract Infection and Antibiogram Profile in Children Attending Debre Tabor Comprehensive Specialized Hospital, Northwest Ethiopia

BACKGROUND

Bacterial urinary tract infections are important public health problems in children. This study was conducted to identify the bacterial agents of urinary tract infections and antibiogram patterns in children.

METHODS

A hospital-based cross-sectional study including 220 children was carried out between November 15, 2021, and March 10, 2022. Simple random sampling was used to enroll participants. The sociodemographic and clinically pertinent information was gathered using a semi-structured questionnaire. Every participant in the study who was ≤15 years old gave clean-catch midstream urine. Urine samples were inoculated onto a cystine lactose electrolyte-deficient agar using a calibrated inoculating loop with a 0.001 ml capacity and then incubated aerobically for 24 hours at 37°C. Subculturing for significant bacteriuria was done on MacConkey and blood agar. Gram staining, biochemical assays, and colony characteristics were used for bacterial identification. The disc diffusion method developed by Kirby and Bauer was used for antimicrobial susceptibility testing. SPSS software version 25 was used for data entry and analysis. To find the risk factors, bivariate and multivariate logistic regression analyses were performed. An association was deemed statistically significant if the p value at the 95 percent confidence interval was less than 0.05.

RESULTS

In this study, the majority (50.5%) of the study participants were males. The mean age of the study participants was 6 ± 0.91 years. It was found that 31.8% of children had urinary tract infections. The most prevalent urinary pathogens among the isolates were E. coli (27.1%) and S. aureus (18.6%). Approximately 56% of the participants were infected with multidrug-resistant pathogens. Additionally, compared to children who have never had a urinary tract infection, children with a history of infection had 1.04 (95 percent confidence interval (CI): 0.39, 2.75) times higher risk of infection.

CONCLUSION

This study has shown an alarming increase in the prevalence of pediatric urinary tract infections which warrants further investigation into multidrug-resistant bacterial infection.

Analysis of Antimicrobial Susceptibility in Bacterial Pathogens Associated with Urinary Tract Infections from Beijing Teaching Hospital in China, 2009-2017

Objective

Since a urinary tract infection (UTI) is easy to relapse and difficult to treat, the antibiotic resistance rate has increased year by year in recent years. This study was to analyze the characteristics of the common pathogenic bacteria and the changes of antibiotic resistance in urinary system infection, so as to guide the standard use of antibiotics in a clinical urinary tract infection and control nosocomial infection effectively.

Methods

A total of 5,669 strains of a urinary tract infection in the hospital from January 2009 to December 2017 were retrospectively analyzed. Bacterial identification and the antibiotic sensitivity test (AST) were analyzed by using a VITEK-2 Compact system.

Results

Of the 5669 pathogens, 3,256 (57.44%) of the strains were Gram-negative bacteria (GNB), 1,474 (26%) were Gram-positive bacteria (GPB), and 939 (16.56%) were fungi. Resistant rates of ESBL-producing strains were all significantly different from non-ESBL-producing strains in Escherichia coli (p < 0.05). The resistance rate of ESBL-producing strains to β-lactam antibiotics was all higher than that of non-ESBL-producing strains in Klebsiella pneumoniae (p < 0.05). The detection rate of vancomycin-resistantEnterococcus faecium and Enterococcus faecalis was 37.3% and 3.1%, respectively, and the detection rate of linezolid-resistantEnterococcus faecium and Enterococcus faecalis was 0.68% and 0%, respectively. The drug resistance rate of candida sp. to fluconazole, itraconazole, and voriconazole was 1.7%, 8.5%, and 3.4%, respectively. No amphotericin B-resistant strains were detected in the research.

Conclusions

Among the 5669 strains isolated from urinary tract infection patients, GNB were the main pathogens. Escherichia coli was the major pathogen. The resistance rate of ESBLs-producingEscherichia coli was higher than that of non-ESBLs-producingEscherichia coli in general; meanwhile, β-lactam/β-lactamase inhibitors and carbapenems maintained good antimicrobial activity against Escherichia coli. The resistance rate of non-ESBLs-producingKlebsiella pneumoniae strains was significantly higher than that of ESBLs-producingKlebsiella pneumoniae strains, and drug resistance was more prominent; most of the antibiotic resistance rates were over 50%. The antimicrobial resistance rate of Enterococcus faecium was significantly higher than that of Enterococcus faecalis. There were rare linezolid-resistant strains. The antimicrobial resistance rate of imidazole to fungi was controlled less than 10%.

Flufenamic Acid, a Promising Agent for the Sensitization of Colistin-Resistant Gram-Negative Bacteria to Colistin

The continuous development of multidrug-resistant (MDR) Gram-negative bacteria poses a serious risk to public health on a worldwide scale. Colistin is used as the last-line antibiotic for the treatment of MDR pathogens, and colistin-resistant (COL-R) bacterial emergence thus has the potential to have a severe adverse impact on patient outcomes. In this study, synergistic activity was observed when colistin and flufenamic acid (FFA) were combined and used for the in vitro treatment of clinical COL-R Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii strains, as shown by checkerboard and time-kill assays. Crystal violet staining and scanning electron microscopy revealed the synergistic action of colistin-FFA against biofilms. When used to treat murine RAW264.7 macrophages, this combination did not induce any adverse toxicity. Strikingly, the survival rates of bacterially infected Galleria mellonella larvae were improved by such combination treatment, which was also sufficient to reduce the measured bacterial loads in a murine thigh infection model. Mechanistic propidium iodide (PI) staining analysis further demonstrated the ability of these agents to alter bacterial permeability in a manner that enhanced the efficacy of colistin treatment. Together, these data thus demonstrate that colistin and FFA can be synergistically combined to combat the spread of COL-R Gram-negative bacteria, providing a promising therapeutic tool with the potential to protect against COL-R bacterial infections and improve patient outcomes. IMPORTANCE Colistin is a last-line antibiotic used for the treatment of MDR Gram-negative bacterial infections. However, increasing resistance to it has been observed during clinical treatment. In this work, we assessed the efficacy of the combination of colistin and FFA for the treatment of COL-R bacterial isolates, demonstrating that the combined treatment has effective antibacterial and antibiofilm activities. Due to its low cytotoxicity and good therapeutic effects in vitro, the colistin-FFA combination may be a potential candidate for research into a resistance-modifying agent to combat infections caused by COL-R Gram-negative bacteria.

Study on Virulence Genes, Drug Resistance and Molecular Epidemiology of Klebsiella pneumoniae with High Virulence in Inner Mongolia, China

Objective

The purpose of this study was to analyse the clinical, microbiological and molecular epidemiological characteristics of patients with pyogenic liver abscess (PLA) caused by Klebsiella pneumoniae (KPN) in Inner Mongolia, China.

Methods

The KPN isolates from 78 KPN-PLA cases admitted to a tertiary teaching hospital in Baotou, Inner Mongolia, from 2016 to 2019 were studied systematically and described comprehensively. The virulence factors, drug resistance and sequence types of KPN in different samples were identified by a wire-drawing test, polymerase chain reaction, a drug susceptibility test and multi-site sequence typing.

Results

There were more male than female KPN-PLA patients (P<0.05). The mortality rate was 2.5%, and KPN-PLA was significantly associated with diabetes mellitus (P<0.05). Most of the KPN isolates in the puncture fluid of patients with KPN-PLA were hypervirulent KPN (HvKP). The positive rate of the KPN-PLA specimens was higher than that of the blood and urine specimens. The KPN isolates of the urine specimens had higher drug resistance than the other two (P<0.05). The hypermucoviscous KPN, aerobic actin (aero) (+), K1 and K2 serotypes accounted for 80.8%, 89.7%, 56.4% and 26.9%, respectively. In addition to ironB (3.8%), the detection rates of virulence factors rmpA, irp2, entB, iucD, aero, wcaG, iutA, kfu, ybtA, iron, fimH and mrkD were higher (69.2%-100.0%). The positive rate of KPN isolates of the KPN-PLA puncture fluid was higher than that of the blood and urine samples (P<0.05). In addition, ST23 was found to be the dominant ST (32.1%) of KPN-PLA in the Baotou region.

Conclusion

In the KPN-PLA specimens, the KPN isolates were more virulent than those in the blood and urine specimens, and a carbapenem-resistant HvKP strain emerged. This research will help improve the understanding of HvKP and provide useful suggestions for KPN-PLA treatments.

Prevalence and Predictors of Multi-Drug Resistant Organisms Among Ambulatory Cancer Patients with Urinary Tract Infections

Purpose

Urinary tract infections (UTIs) are among the most common community-acquired infections in patients with cancer. Though the prevalence of multi-drug resistant organisms (MDROs) has increased, there are limited studies on MDROs among ambulatory cancer patients with UTIs. Therefore, we aimed to evaluate the prevalence and predictors of MDROs in this patient population.

Patients and Methods

A retrospective study of adult cancer patients treated for bacterial UTIs in the ambulatory setting at King Hussein Cancer Center. The medical laboratory's system was used to identify positive urine cultures taken in the ambulatory setting, between Aug 2020 and March 2021. UTIs were defined as a positive urine culture along with the initiation of antibiotics empirically or as definitive therapy. Patient characteristics, as well as the type and sensitivity of the bacterial organisms, were recorded. MDROs were defined as intrinsic or acquired non-susceptibility to at least one agent in three or more antimicrobial categories. Logistic regression was used to identify predictors that were independently associated with MDROs.

Results

A total of 376 patients had UTIs that met the inclusion criteria; mean age 60.5±15.1 (SD) years and 330 (87.8%) had solid tumors. Gram-negative bacteria was recorded in the majority of UTIs (n = 368, 97.9%), the most common being Escherichia-coli (n = 220, 59.8%) and Klebsiella-pneumonia (n = 68, 18.5%). MDROs were recorded in 226 (60.1%) of urine cultures, with the majority being extended-spectrum-beta-lactamase producing organisms (n = 142, 62.8%). The only significant predictor was having had a UTI with MDRO within the past 6 months (OR 5.6, 95% CI 2.1-15.2).

Conclusion

More than half of the positive urine cultures of cancer patients treated for UTIs in the ambulatory setting were MDROs. A subsequent UTI due to MDROs is more likely to occur in patients who had a UTI with an MDRO within the past 6 months.

Carbapenem-Resistant Klebsiella pneumoniae: Virulence Factors, Molecular Epidemiology and Latest Updates in Treatment Options

Klebsiella pneumoniae is a Gram-negative opportunistic pathogen responsible for a variety of community and hospital infections. Infections caused by carbapenem-resistant K. pneumoniae (CRKP) constitute a major threat for public health and are strongly associated with high rates of mortality, especially in immunocompromised and critically ill patients. Adhesive fimbriae, capsule, lipopolysaccharide (LPS), and siderophores or iron carriers constitute the main virulence factors which contribute to the pathogenicity of K. pneumoniae. Colistin and tigecycline constitute some of the last resorts for the treatment of CRKP infections. Carbapenemase production, especially K. pneumoniae carbapenemase (KPC) and metallo-β-lactamase (MBL), constitutes the basic molecular mechanism of CRKP emergence. Knowledge of the mechanism of CRKP appearance is crucial, as it can determine the selection of the most suitable antimicrobial agent among those most recently launched. Plazomicin, eravacycline, cefiderocol, temocillin, ceftolozane-tazobactam, imipenem-cilastatin/relebactam, meropenem-vaborbactam, ceftazidime-avibactam and aztreonam-avibactam constitute potent alternatives for treating CRKP infections. The aim of the current review is to highlight the virulence factors and molecular pathogenesis of CRKP and provide recent updates on the molecular epidemiology and antimicrobial treatment options.

Long Term Characteristics of Clinical Distribution and Resistance Trends of Carbapenem-Resistant and Extended-Spectrum β-Lactamase Klebsiella pneumoniae Infections: 2014-2022

Purpose

Through long-term and large sample size statistical analysis, we revealed the pattern of Klebsiella pneumoniae (KP) infection and drug resistance and provided epidemiological data for the treatment and prevention and control of multidrug-resistant bacterial infection in our hospital.

Patients and Methods

Strains were identified using the BD Phoenix^TM100 system, minimal inhibitory concentration of antibiotics were determined by the broth method, and data were statistically analyzed using WHONET 5.6 and SPSS27.0.

Results

The isolation rate of KP from Enterobacteriaceae (26.2%, 4547/17358) in our hospital showed an increasing annual trend, ranking second only to Escherichia coli. Carbapenem-resistant KP (CRKP) accounted for the highest proportion of carbapenem-resistant Enterobacteriaceae (72.2%, 431/597), showing an upward trend. Infected patients had a male-to-female ratio of approximately 2:1 and were mainly >60 years of age (66.2%), with intensive care units being the most commonly distributed department. Sputum was the most common specimen type (74.0%). Compared with spring and summer, autumn and winter were the main epidemic seasons for KP and extended-spectrum β-lactamase KP (ESBL-KP). The resistance rate of KP to common antibiotics was low, but all showed an increasing trend each year. ESBL-KP was >90% resistant to piperacillin, amoxicillin/clavulanic acid, and cefotaxime and less resistant to other common antibiotics, but showed an increasing trend in resistance to most antibiotics. CRKP resistance to common antibiotics was high, with resistance rates >90%, excluding amikacin (64.1%), gentamicin (87.4%), cotrimoxazole (44.3%), chloramphenicol (13.6%), and tetracycline (30.5%).

Conclusion

KP in our hospital mainly caused pulmonary infection in older men, which occurred frequently in autumn and winter, and the isolation and drug resistance rates showed an increasing trend. Age over 70 years, admission to intensive care unit, and urinary tract infection were found to be the risk factors for CRKP and ESBL-KP-resistance.

Magnitude and Molecular Characterization of Extended-Spectrum β-Lactamase Genes among Klebsiella pneumoniae Isolates in a Large Tertiary Hospital in Ethiopia

Background Extended-spectrum β-lactamases (ESBLs)-producing Klebsiella pneumoniae is reported worldwide increasingly. However, studies on ESBLs are still scarce in Ethiopia. Therefore, the current study aimed to determine the magnitude and resistance patterns of ESBL-producing K. pneumoniae as well as the frequency of ESBL-encoding genes.Methods A cross-sectional study was conducted from September 2018 to February 2019 at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia among a total of 132 non-duplicate K. pneumoniae isolates. Phenotypic detection of ESBL production was done using Combined Disc Test. ESBL-encoding genes of bla_CTX-M, bla_TEM, and bla_SHV were detected through multiplex PCR.Results The magnitude of ESBL production was 102/132 (77.3%). ESBL positive isolates were 100% resistant to ceftriaxone, cefotaxime, and cefuroxime. Co-resistance of ESBL-positive isolates to other non β-lactam antimicrobials was high to trimethoprim-sulfamethoxazole (96.1%) followed by tetracycline (75.5%) and gentamicin (73.5%). However, these isolates showed high susceptibility to amikacin (96.1%) and meropenem (89.2%). From the total ESBL-positive isolates, 82.6%, 73.5%, and 75% carried bla_CTX-M, bla_TEM, and bla_SHV genes, respectively. The majority 78/102 (76.5%) of ESBL-positive isolates harbored all three types of ESBL genes simultaneously.Conclusions The magnitude of ESBL-producing K. pneumoniae isolates was very alarming in the study area. The co-occurrence of bla_CTX-M, bla_TEM, and bla_SHV genes is high, demanding large-scale studies to evaluate the presence of antimicrobial resistance super-clones. ESBL-producing isolates showed high resistance to most of the antimicrobials, needing phenotypic detection of ESBL regularly for better management of patients.

Evidence of Sharing of Carbapenem-Resistant Klebsiella pneumoniae Strains Between Intensive Care Unit Patients and the Environment

Purpose

Carbapenem-resistant Klebsiella pneumoniae (CR-KP) has emerged as an important public health threat. Intestinal colonization with CR-KP increases the risk of infection and death, especially in intensive care unit patients. To clarify the source of colonizing bacteria is very important to prevent the spread of CR-KP, so the purpose of this study was to explore the relationship between the ward environment and intestinal colonization of CR-KP.

Methods

In this study, 353 environmental swabs from ICU (Intensive Care Unit) wards and 241 anal swab samples from ICU patients were collected and screened on MacConkey plates containing 2 μg/mL ertapenem, and the origin and genotype of CR-KP were analyzed by PCR and sequencing. The sequence type of the strains was also obtained by multi-locus sequence type (MLST) analysis, and plasmid conjugation test was used to clarify whether CR-KP can promote the transmission of drug resistance genes through plasmid integration and rearrangement.

Results

A total of 20 CR-KP environmental strains and 7 intestinal strains were obtained, most of which were bla _OXA-48 resistant genotypes. Four different STs were identified by multi-locus sequence type (MLST) analysis, among which the large logarithm was ST485 type, and PFGE clustering showed that the similarity between them was >85%. In the plasmid transcoupling assay, we report that one of the Klebsiella pneumoniae drug-resistant plasmids was successfully transferred to E. coli, indicating that it may promote the spread of drug-resistant genes through plasmid integration and rearrangement.

Conclusion

Our research suggests that the environment may be a potential source of CR-KP and that there is a need for us to adopt more effective disinfection measures.

Genetic and Phenotypic Characteristics of Carbapenem-Resistant Klebsiella pneumoniae Isolates from a Tertiary Hospital in Beijing

Objective

Klebsiella pneumoniae is a common multidrug-resistant pathogen that jeopardizes the health of hospitalized patients. We aimed to study the phenotypic and genotypic characteristics of carbapenem-resistant K. pneumoniae (CRKP) isolates from a hospital in Beijing.

Methods

Twenty-four CRKP clinical isolates were collected within a half-year to investigate antimicrobial resistance and genomic characteristics. Illumina and Nanopore sequencing were performed to assemble and annotate genomes.

Results

All strains were multi-drug resistant. Twenty-two strains carried the bla _KPC-2 gene and two harbored bla _NDM-5. Multilocus sequence type(MLST) analysis identified five sequence types; most isolates belonged to ST11. Three strains were isolated from the same patient; each carried a different plasmid replicon, either IncFII _(pHN7A8), IncX, or IncFIB _(K).

Conclusion

This study furthers the understanding of CRKP antimicrobial resistance genotypes, and may facilitate the control of nosocomial infections caused by antimicrobial-resistant pathogens.

Effect of Carbapenem-Resistant Klebsiella pneumoniae Infection on the Clinical Outcomes of Kidney Transplant Recipients

Background

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection has proven to be difficult to control and typically presents with devastating effects.

Methods

This retrospective study was conducted on the renal recipients at our institution between January 2021 to January 2022. Clinical data was collected to identify factors associated with CRKP infection and clinical outcomes.

Results

There were 104 cases out of 186 total renal recipients who presented with at least one infection within 3 months after KT, and 14 cases developed unfavorable clinical outcomes. We identified 16 confirmed CRKP infected cases with the incidence of 8.60%. Possible donor derived infection (DDI) (OR = 6.743; 95% CI: 1.477–30.786; P = 0.014) were independent risk factors for the occurrence of CRKP infection of renal recipients in our analysis, CRKP infection (OR = 20.723; 95% CI: 3.448–124.547; P = 0.001) and pneumonia (OR = 28.458; 95% CI: 1.956–413.984 P = 0.014) were independent risk factors for the occurrence of unfavorable clinical outcomes following KT, and the occurrence of unfavorable clinical outcomes following KT were significantly associated with CRKP infection (r = 0.535; P < 0.001) and antibiotic regimen containing ceftazidime/avibactam (CZA) (r = −0.655; P = 0.006). The use of CZA was significantly different in the comparison of antibiotic regimens between the CRKP infected renal recipients with unfavorable outcomes and CRKP infected patients with favorable outcomes.

Conclusion

It is possible that DDI can lead to CRKP infection, and CRKP infection and pneumonia were closely correlated with poor prognosis. The use of CZA may play a role in avoiding the unfavorable outcomes of CRKP infected recipients.

Prompt and Appropriate Antimicrobial Therapy Improves Outcomes of NDM-Producing and KPC-Producing Klebsiella pneumoniae Bloodstream Infections in Patients Hospitalized for COVID-19: A Comparative Retrospective Case-Series

Secondary bloodstream infections (BSIs) caused by KPC- and NDM-producing Klebsiella pneumoniae (K.p.) during the course of COVID-19 infections lead to significant mortality. Herein, a comparative retrospective case series of KPC- or NDM-K.p. BSIs occurring in COVID-19 subjects treated with Ceftazidime/Avibactam (CAZ/AVI) for KPC-K.p., or CAZ/AVI+ Aztreonam (ATM) for NDM-K.p is reported. All patients hospitalized for COVID-19 in two Italian hospitals with a BSI between March and September 2021 were included. The main outcome was 14-day mortality. Overall, 44 patients were included: 23 with KPC-K.p. and 21 with NDM-K.p. BSIs. The median (q1–q3) age was 67 (57–75) years, and 32 (72%) were males. The two groups were similar in terms of baseline comorbidity, or severity of COVID-19. Notably, 14-day mortality of KPC-K.p. BSIs and NDM-K.p. BSIs (26% vs. 38%, p = 0.521) and 28-day mortality (35% vs. 48%, p = 0.541) were similar. A Cox regression model of delayed initiation of an appropriate antibiotic therapy after the onset of symptoms independently predicted mortality: initiation between 24 and 72 h (aHR = 12.03; 95% CI = 1.10–130, p = 0.041); and initiation after 72h (aHR = 36.9, 95% CI = 3.22–424, p = 0.004). Moreover, a trend towards an increased risk of mortality was observed for polymicrobial infections (aHR = 3.73, 95% CI = 0.87–15.8, p = 0.074), while a protective effect was observed for a beta-lactam loading dose at the start of treatment (aHR = 0.16, 95% CI = 0.02–1.10, p = 0.064). The high mortality of KPC and NDM-K.p. BSIs in COVID-19 patients may be reduced by an early and appropriate antibiotic therapy. Further efforts should be made to develop antimicrobial stewardship and infection control programs in COVID-19 wards.

Carbapenem-Resistant Klebsiella pneumoniae: Diversity, Virulence, and Antimicrobial Resistance

Background

Klebsiella pneumoniae (K. pneumoniae) is one of the most important pathogens in nosocomial infections. It has resistance to most antibiotics, even carbapenem, resulting in restricted therapeutic options.

Purpose

We tried to assess the antimicrobial resistance and virulence fitness of carbapenem-resistant K. pneumoniae (CRKP) in addition to their phenotypic and genotypic diversity.

Materials and Methods

The conventional methods, automated Vitek-32 system, and antimicrobial susceptibility pattern were used to detect CRKP isolates. Virulence and resistance genes profiles were created by using PCR technique. The correlation analysis was done by using R-program.

Results

The antimicrobial resistance profile for all our K. pneumoniae isolates was shocking as the MDR and CRKP were the most prominent phenotypes. Unfortunately, high degrees of heterogeneity among our CRKP isolates were recorded, as 97.5% of them were differentiated into different clusters. We found a negative correlation between the existence of virulence and antimicrobial resistance genes. In contrast to sputum and urine CRPK isolates, the blood isolates showed high antimicrobial resistance and low virulence fitness. Finally, K. pneumoniae creates several outbreaks and crises in Egypt owing to the highly heterogeneity and the wide spread of multidrug-resistant (MDR) and multi-virulent CRKP phenotypes.

Conclusion

Our results are significant and alarming to health organizations throughout the world for the severity and heterogeneity of K. pneumoniae infections. Therefore, the traditional method for treatment of CRKP infections must be renewed. Additionally, the treatment protocols must be well correlated with the site of infections, phenotypes, and genotypes of CRKP strains.

The detection of urinary viruses is associated with aggravated symptoms and altered bacteriome in female with overactive bladder

Although it is known that changes in bacterial components of the urinary microbiome are associated with overactive bladder (OAB), the specific role of viruses is still insufficiently investigated. The aim of the present study is to evaluate the role of urinary viruses in woman with OAB, and analyze the potential relationship between viruses, bacteria and disease. Catheterized urine samples were collected from 55 women with OAB and 18 control individuals. OAB patients fulfilling the following criteria were considered eligible for this study: female, 18 years of age or older; presented with classic OAB symptoms defined by the International Continence Society; and OAB Symptom Score (OABSS) total score ≥ 3 points and question 3 (urgency) score ≥ 2 points. Based on results of metagenomic next-generation sequencing (mNGS), all participants were divided into virus-infected and virus-uninfected groups for analysis. The results of mNGS showed that the diversity of the OAB group was lower than that of the control group when focused on bacterial sequences, which was consistent with our previous study. According to the questionnaire filled out by the patients, OABSS and 8-item OAB questionnaire, female OAB patients who had viruses detected in their urine had more severe symptoms. In parallel, John Cunningham virus (mainly subtype 7 and subtype 2) was the most frequently detected virus in urine. Correlation analysis indicated that risk factors for virus infection in OAB patients include age, habit of holding urine and pelvic surgery history. Given our preliminary data, viral infection can aggravate OAB severity and affect the composition of bacterial. Further research is required to explain how viral infections can aggravate OAB patient symptoms and cause bacterial changes.

Analysis of a Refractory Case of Pediatric Meningitis Caused by Klebsiella pneumoniae Co-Resistant to Carbapenems and Polymyxins

We report our clinical exploration experience treating a 6-year-old girl with a postoperative central nervous system (CNS) infection of prolonged invasion with Klebsiella pneumoniae (K. pneumoniae) co-resistant to carbapenems and polymyxin B. Although rational antibiotic therapy and effective source control measures were applied, the infection was not controlled eventually. To understand the mechanism of infection, whole-genome sequencing (WGS) was used to explore the resistance mechanism, and the susceptibility test was used to observe the efficacy of ceftazidime–avibactam (CAZ-AVI) in vitro. It is currently uncertain whether CAZ-AVI could be used as a salvage therapy for pediatric CNS infection. Therefore, we hope to share this case to seek medical help worldwide to treat pediatric CNS infection.

Knowledge, Practice and Associated Factors of Health Care Workers on Prevention of Catheter-Associated Urinary Tract Infections in South Wollo Zone Public Hospitals, Northeast Ethiopia

Introduction

Health care providers are responsible for inserting and maintaining urinary catheters. Hence, it is very important that health care professionals need to be skillful and knowledgeable to prevent urinary tract infection for those patients undergoing indwelling catheter. Thus, this study aimed to assess knowledge, practice and associated factors of health care workers on prevention of catheter-associated urinary tract infections in South Wollo zone public hospitals, Northeast Ethiopia.

Methods

An institution-based cross-sectional study design was employed by using a simple random sampling technique among 413 health care workers. Data were entered into Epi-Data version 4.6 and were exported to SPSS version 26 for analysis. Bivariable logistic regression analyses were performed, and variables with P-value less than 0.25 were fitted to multivariable logistic regression. In multivariable regression analysis, variables having p-value <0.05 were declared as significant factors for outcome variable.

Results

Out of the total 413 health care workers, 298 (72.2%) had adequate knowledge and 233 (56.4%) had adequate level of practice towards catheter-associated urinary tract infection prevention. Received training [AOR = 2.33, 95% CI: 1.404–3.889] and being bachelor degree holder [AOR = 1.90, 95% CI: 1.084–3.359] were significantly associated with adequate knowledge. On the other hand, being master and doctor [AOR = 4.71, 95% CI: 1.768–12.56], adequate level of knowledge [AOR = 2.90, 95% CI: 1.785–4.723], received training [AOR = 2.09, 95% CI: 1.315–3.338] and work experience ≥20 years [AOR = 5.82, 95% CI: 1.497–22.69] were significantly associated with adequate level of practice.

Conclusion

A substantial proportion of health care workers had inadequate knowledge and practice towards catheter-associated urinary tract infection prevention. Therefore, health care workers should strictly follow infection prevention guidelines and should update their knowledge and practice by taking short and long term training.

Multidrug-Resistant Bacteria Isolated from Blood Culture Samples in a Moroccan Tertiary Hospital: True Bacteremia or Contamination?

Purpose

To demonstrate the relevance of clinico-biological correlation in the interpretation of positive blood cultures (BC) for multidrug-resistant (MDR) bacteria, among adult and pediatric patients, in order to distinguish between true bacteremia (TB) and contaminations and to evaluate the impact on patient management.

Patients and Methods

This six-month study was conducted at Mohammed VI University Hospital in Marrakech. All MDR bacteria isolated from BCs carried out on hospitalized patients during this period were included. For each positive BC to MDR microorganism, demographic and clinical characteristics, laboratory findings, therapeutic and evolution data were collected.

Results

TB was considered in 157 (94.6%) of the 166 positive-culture episodes for MDR bacteria, while 9 (5.4%) were classified as false-positive. Contamination rate was 0.2% (9/3824). TB and contaminations occurred mainly in intensive care units (ICUs), with the neonatal ICU being the most concerned (p = 0.016). Clinical signs of sepsis were present in all TB patients, with a significant difference between the two groups (p = 0.000). CRP values were higher in the TB group (p = 0.000). The most isolated true pathogens were ESBL-producing Enterobacterales (50%) and carbapenem-resistant Enterobacterales (33.3%). They also predominated in contaminated BCs. Isolation of the same microorganism from other sites was significantly associated with TB (p = 0.012). In contrast to the contaminations group, the difference in the clinical course of TB patients, according to whether or not they received appropriate probabilistic antibiotics, was statistically significant (p = 0.000). These patients had longer hospital stays and longer durations of antibiotic therapy. The overall mortality rate was 39.6%.

Conclusion

Distinguishing between MDR-positive BCs representing clinically significant bacteremia or simple contamination requires a careful clinical, biological, and microbiological confrontation of each MDR positive BC in order to avoid unnecessary overuse of broad-spectrum antibiotics and thus reduce resistance selective pressure.

Diversity of Ceftazidime-Avibactam Resistance Mechanism in KPC2-Producing Klebsiella pneumoniae Under Antibiotic Selection Pressure

Purpose

The aim of this study was to understand the resistance mechanism of ceftazidime/avibactam (CZA) in carbapenem-resistant Klebsiella pneumoniae under antibiotic selection pressure.

Patients and Methods

Four CZA-resistant Klebsiella pneumoniae strains were isolated from two patients, and six CZA-resistant strains that were produced in vitro were screened from 25 carbapenem-resistant Klebsiella pneumoniae strains. The mechanisms of resistance to CZA of these strains were characterized by PCR and Sanger sequencing.

Results

CZA-resistant Klebsiella pneumoniae with different resistance mechanisms (including upregulation of the expression of efflux pumps and KPC variants (KPC-14, KPC-44)) were isolated from the same patient (patient 1). In patient 2, the resistance mechanism of CZA-resistant Klebsiella pneumoniae was the mutation of KPC-2 to KPC-33. In addition, among the CZA-resistant Klebsiella pneumoniae that were produced in vitro, we found 3 new KPC variants: KPC-86 (D179G), KPC-87 (GT241A) and KPC-88 (G523T).

Conclusion

In this study, although the CZA-resistant bacteria originated from only two clinical patients, four different mechanisms of CZA resistance were detected. In the in vitro induction experiment, the mechanisms of resistance to CZA in strains from different patients were also different. The above result implies that the mechanisms of resistance to CZA are generally random and diverse. Therefore, elucidating the mechanism of resistance to CZA can provide a certain theoretical basis for the effective response of CZA-resistant strains and the selection of antibiotics.

Disease burden and long-term trends of urinary tract infections: A worldwide report

Background

Urinary tract infections (UTIs) are one of the most common infections worldwide, but little is known about their global scale and long-term trends. We aimed to estimate the spatiotemporal patterns of UTIs' burden along with its attributable risk factors at a global level, as well as the variations of the burdens according to socio-demographic status, regions, nations, sexes, and ages, which may be helpful in guiding targeted prevention and treatment programs.

Methods

Data from the Global Burden of Disease Study 2019 were analyzed to depict the incidence, mortality, and disability-adjusted life years (DALYs) of UTIs in 204 countries and territories from 1990 to 2019 by socio-demographic status, nations, region, sex, and age.

Results

Globally, 404.61 million cases, 236,790 deaths, and 520,200 DALYs were estimated in 2019. In particular, 2.4 times growth in deaths from 1990 to 2019 was observed, along with an increasing age-standardized mortality rate (ASMR) from 2.77/100,000 to 3.13/100,000. Age-standardized incidence rate (ASIR) was consistently pronounced in regions with higher socio-demographic index (SDI), which presented remarkable upward trends in ASMR and age-standardized DALY rate (ASDR). In contrast, countries with a low SDI or high baseline burden achieved a notable decline in burden rates over the past three decades. Although the ASIR was 3.6-fold higher in females than males, there was no sex-based difference in ASMR and ASDR. The burden rate typically increased with age, and the annual increasing trend was more obvious for people over 60 years, especially in higher SDI regions.

Conclusions

The burden of UTIs showed variations according to socio-demographic status, nation, region, sex, and age in the last three decades. The overall increasing burden intimates that proper prevention and treatment efforts should be strengthened, especially in high-income regions and aging societies.

Isolation and Identification of Escherichia coli and Klebsiella pneumoniae Strains Resistant to the Oxyimino-Cephalosporins and the Monobactam by Production of GES Type Extended Spectrum Bêta-Lactamase (ESBL) at Saint Camille Hospital Center in Ouagadougou, Burkina Faso

Background

Bacterial resistance to beta lactamins is a real public health problem as it complicates treatment strategies. Several types of beta lactamase confer this resistance. Numerous studies report a high prevalence of ESBL producers among Gram-negative bacilli. The objective of this work was to identify the presence of the resistance gene GES in strains of E. coli and K. pneumoniae in Burkina Faso.

Methods

During this study 39 strains of E. coli and K. pneumoniae resistant to oxyimino-cephalosporin and monobactam were collected in several samples and analyzed to determine the presence of the beta lactamase resistance gene Bla_GES by classic PCR.

Results

In the present study, resistant strains were observed in 21 E. coli and 18 K. pneumoniae. Among producers of ESBL isolates, the presence of the GES gene was detected up to 63% in E. coli and 37% in K pneumoniae.

Conclusion

This study highlighted the presence of the GES gene in strains of E. coli and K. pneumoniae resistant to oxyimino-cephalosporin and monobactam in Burkina Faso. This highlights the presence of new ESBL in Burkina, which is of great interest for the proper care of patients and the control of resistance to antibiotics.

Impact of Pharmacist-Led Implementation of a Community Hospital-Based Outpatient Parenteral Antimicrobial Therapy on Clinical Outcomes in Thailand

Few studies have analyzed community hospital-based parenteral anti-infective therapy (CohPAT). We aimed to assess the clinical impact of a pharmacist-led implementation of a clinical practice guideline (CPG) for CohPAT, and to determine the pharmacist’s role in CohPAT medication management. The prospective-period patients (post-implementation group) were compared with the historical control-period patients (pre-implementation group) for receiving a continuous antimicrobial parenteral injection. A CPG was used for laboratory testing for efficacy and safety, the monitoring of adverse drug events during admission, microbiology results coordination, and dosage adjustment. For any antimicrobial drug-related problems, the pharmacist consulted with the clinicians. Over 14 months, 50 participants were included in each group. In the pre-implementation period, 7 (14%) and 4 (8%) out of 50 patients received an inappropriate dosage and nonlaboratory monitoring for dose adjustment, respectively. The patients received the proper dosage of antimicrobial agents, which increased significantly from 78% pre- to 100% post-implementation (p = 0.000). The pharmacist’s interventions during the prospective-period were completely accepted by the clinicians, and significantly greater laboratory monitoring complying with CPG was given to the postimplementation group than the pre-implementation group (100% vs. 60%; p = 0.000). Significantly less patients with unfavorable outcomes (failure or in-hospital mortality) were observed in the post-implementation than in the pre-implementation (6% vs. 26%; p = 0.006) group. For the logistic regression analysis, lower respiratory infection (adjusted OR, aOR 3.68; 95%CI 1.13–12.06) and the post-implementation period (aOR 0.21; 95%CI 0.06–0.83) were significant risk factors that were associated with unfavorable outcomes. Given the better clinical outcomes and the improved quality of septic patient care observed after implementation, pharmacist-led implementation should be adopted in healthcare settings.

Antimicrobial resistance among GLASS pathogens in Morocco: an epidemiological scoping review

BACKGROUND

Monitoring of antimicrobial resistance (AMR) is of great importance due to the frequency of strains becoming increasingly resistant to antibiotics. This review, using a public health focused approach, which aims to understand and describe the current status of AMR in Morocco in relation to WHO priority pathogens and treatment guidelines.

METHODS

PubMed, ScienceDirect and Google Scholar Databases and grey literature are searched published articles on antimicrobial drug resistance data for GLASS priority pathogens isolated from Morocco between January 2011 and December 2021. Articles are screened using strict inclusion/exclusion criteria. AMR data is extracted with medians and IQR of resistance rates.

RESULTS

Forty-nine articles are included in the final analysis. The most reported bacterium is Escherichia coli with median resistance rates of 90.9%, 64.0%, and 56.0%, for amoxicillin, amoxicillin-clavulanic acid, and co-trimoxazole, respectively. Colistin had the lowest median resistance with 0.1%. A median resistance of 63.0% is calculated for amoxicillin-clavulanic acid in Klebsiella pneumonia. Imipenem resistance with a median of 74.5% is reported for Acinetobacter baumannii. AMR data for Streptococcus pneumonie does not exceed 50.0% as a median.

CONCLUSIONS

Whilst resistance rates are high for most of GLASS pathogens, there are deficient data to draw vigorous conclusions about the current status AMR in Morocco. The recently join to the GLASS system surveillance will begin to address this data gap.

Facile Green Synthesis of Silver Nanoparticles Using Aqueous Leaf Extract of Origanum majorana with Potential Bioactivity against Multidrug Resistant Bacterial Strains

The high prevalence of nosocomial bacterial resistance contributes to significant mortality and morbidity around the world; thus, finding novel antibacterial agents is of vital concern. Accordingly, the present study attempted to synthesize silver nanoparticles (AgNPs) using a green approach. Aqueous leaf extract of Origanum majorana was used to synthesize AgNPs and the antibacterial efficiency against multidrug resistant bacterial strains was detected. Characterization of the biogenic AgNPs was performed using ultraviolet-visible spectrophotometry (UV-Vis), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR) analysis, and X-ray diffraction analysis (XRD). The disc diffusion method was used to detect the antibacterial activity of AgNPs against three nosocomial multidrug-resistant strains. Preliminary UV-Vis analysis revealed the biosynthesis of AgNPs due to peak formation at 374 nm, corresponding to the surface plasmon resonance (SPR) of biogenic AgNPs. TEM micrographs detected the synthesis of small AgNPs with an average particle size of 26.63 nm. EDX analysis revealed the presence of the following elements: oxygen (3.69%), carbon (2.93%), aluminum (1.29), silicon (2.83%), chloride (17.89%), and silver (71.37%). Furthermore, XRD analysis revealed the presence of diffraction peaks at 2 theta (θ) degrees of 38.18°, 44.36°, 64.35°, and 77.54°, assigned to the planes of silver crystals (111), (200), (220), and (311), respectively. Collectively, these findings affirm the synthesis of biogenic AgNPs with potential physicochemical characteristics. The antimicrobial efficiency of the biogenic AgNPs indicated that Klebsiella pneumoniae strain was the most susceptible strain at concentrations of 50 and 100 µg/disk, with inhibitory zones of 21.57 and 24.56 mm, respectively. The minimum inhibitory concentration (MIC) of AgNPs against Klebsiella pneumoniae strain was found to be 10 µg/mL, while the minimum bactericidal concentration (MBC) was found to be 20 µg/mL. In conclusion, aqueous leaf extract of O. majorana mediated synthesis of small sized AgNPs, with potential antimicrobial effectiveness against multidrug-resistant bacterial pathogens.

Distribution and drug sensitivity of pathogenic bacteria in diabetic foot ulcer patients with necrotizing fasciitis at a diabetic foot center in China

Background

Diabetic foot ulcer is one of the major complications for patients with diabetes, and has become an important cause of non-traumatic amputation. Necrotizing fasciitis is a life-threatening soft-tissue infection involving the fascia and subcutaneous tissue. When diabetic foot ulcers are complicated by necrotizing fasciitis (DNF), this increases the risk for amputation and mortality, making DNF treatment more complicated, and eventually leading to amputation and mortality. However, studies on pathogenic bacteria’s distribution and drug sensitivity in DNF patients remain lacking. This study investigated the distribution and susceptibility of pathogenic bacteria in DNF patients, and provided empirical antibacterial guidance for the clinic.

Methods

In a single diabetic foot center, the results from microbial cultures and drug susceptibility tests of patients with DNF from October 2013 to December 2020 were collected and analyzed.

Results

A total of 101 DNF patients were included in this study, of whom 94 had positive culture test results. A total of 124 pathogens were cultured, including 76 Gram-positive bacterial strains, 42 Gram-negative bacterial strains, and six fungal strains. Polymicrobial infections accounted for 26.7% and monomicrobial infections accounted for 66.3%. Staphylococcus aureus was the most common bacterium isolated, followed by Enterococcus faecalis and Streptococcus agalactiae. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Proteus mirabilis were the most common Gram-negative bacteria. Thirty-five strains of multi-drug resistant bacteria were isolated, representing 28.2% of the total isolates. Gram-positive bacteria were more sensitive to levofloxacin, moxifloxacin, vancomycin, teicoplanin, tigecycline, and linezolid, while Gram-negative bacteria were more sensitive to amikacin, piperacillin/tazobactam, cefoperazone/sulbactam, ceftazidime, cefepime, imipenem, and meropenem.

Conclusions

Gram-positive bacteria were the main bacteria isolated from DNF patients. The bacterial composition, the proportion of multi-drug resistant bacteria among the pathogens, and the high risk for amputation should be fully considered in the initial empirical medication, and broad-spectrum antibacterials are recommended.

Bacterial Ventilator-Associated Pneumonia in COVID-19 Patients: Data from the Second and Third Waves of the Pandemic

During the coronavirus disease 2019 (COVID-19) pandemic, many patients requiring invasive mechanical ventilation were admitted to intensive care units (ICU) for COVID-19-related severe respiratory failure. As a matter of fact, ICU admission and invasive ventilation increased the risk of ventilator-associated pneumonia (VAP), which is associated with high mortality rate and a considerable burden on length of ICU stay and healthcare costs. The objective of this review was to evaluate data about VAP in COVID-19 patients admitted to ICU that developed VAP, including their etiology (limiting to bacteria), clinical characteristics, and outcomes. The analysis was limited to the most recent waves of the epidemic. The main conclusions of this review are the following: (i) P. aeruginosa, Enterobacterales, and S. aureus are more frequently involved as etiology of VAP; (ii) obesity is an important risk factor for the development of VAP; and (iii) data are still scarce and increasing efforts should be put in place to optimize the clinical management and preventative strategies for this complex and life-threatening disease.

A Cross-Sectional Study to Evaluate Antimicrobial Susceptibility of Uropathogens from South Punjab, Pakistan

Background

Urinary tract infections (UTIs) are a common infection caused by uropathogenic bacteria. Drug resistance against common antibiotics is a leading cause of treatment failure in UTIs.

Objective

This study was conducted to check the prevalence of antimicrobial susceptibility against uropathogens and identify the best treatment option against UTIs.

Methods

In this cross-sectional study, urine samples (n = 1000) were collected and cultured for pure bacterial growth by using cysteine-lactose-electrolyte-deficient (CLED) media. After physical and biochemical characterization, antibacterial susceptibility was performed by the Kirby-Bauer disk diffusion method.

Results

Uropathogenic bacteria were successfully isolated in 57% (n = 572) of total tested samples (n = 1000). Escherichia coli 51.2% (n = 293/572), Klebsiella species 15.4% (n = 88/572), Enterococcus species 15.4% (n = 88/572), Pseudomonas species 9.4% (n = 54/572), Staphylococcus aureus 3.2% (n = 18/572), coagulase-negative Staphylococci (CoNS) 3.0% (n = 17/572) and Proteus species 2.4% (n = 14/572) were the most prevalent organism in UTIs. Prevalence of Gram-negative rods (GNRs) was 78.5% (n = 449/572) among UTI patients as compared to Gram-positive cocci (GPCs) 21.5% (n = 123/572). Escherichia coli 65.3% (n = 293/449), Klebsiella species 19.6% (n = 88/449), Pseudomonas species 12.0% (54/449) and Proteus species 3.1% (n = 14/449) were the most prevalent GNRs in UTIs, while Enterococcus species 71.5% (n = 88/123), Staphylococcus aureus 14.6% (n = 18/123) and coagulase-negative Staphylococci (CoNS) 13.8% (17/123) were the most prevalent GPCs in UTIs. The majority of isolated uropathogens showed resistance against routinely used antibiotics. However, teicoplanin and linezolid were the most effective drugs against GPCs and piperacillin/tazobactam, meropenem and imipenem were the most effective drugs against GNRs. Nitrofurantoin and fosfomycin were shown to be most effective against both GNRs and GPCs.

Conclusion

In conclusion, Escherichia coli (GNRs) and Enterococcus species (GPCs) are the most prevalent organisms among UTIs patients, which are shown to be antibiotic-resistant to the most commonly used antibiotics. However, nitrofurantoin and fosfomycin are the most effective drugs against uropathogens in UTIs.

Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii Isolates Among Intensive Care Unit Patients and Environment

Objective

Methods

Results

Conclusion

Characterization of virulence factors and antibacterial activity of curcumin in hypervirulent Klebsiella pneumoniae

Aim: Klebsiella pneumoniae is a threat to human health due to its carbapenem-resistance and hypervirulent phenotype. Curcumin is a well-known antimicrobial agent. Hence, it is important to investigate the antivirulence activity of curcumin against hypervirulent K. pneumoniae isolates. Materials & methods: Carbapenemase presence and prevalence of hypervirulent isolates were determined. Inhibition of biofilm formation and expression of virulence genes were analyzed by colorimetry and real-time PCR tests. Results: Sixteen hypervirulent K. pneumoniae isolates were identified. The optimum activity of curcumin was detected at 1/2 minimum inhibitory concentration. Curcumin possessed appropriate antibiofilm, anti-efflux and anticapsule activities. Conclusion: According to the crucial role of biofilm, capsule and efflux systems in the pathogenesis of hypervirulent K. pneumoniae, curcumin may be used to improve anti-Klebsiella treatment.

How Good are Bacteriophages as an Alternative Therapy to Mitigate Biofilms of Nosocomial Infections

Bacteria survive on any surface through the generation of biofilms that provide a protective environment to grow as well as making them drug resistant. Extracellular polymeric matrix is a crucial component in biofilm formation. The presence of biofilms consisting of common opportunistic and nosocomial, drug-resistant pathogens has been reported on medical devices like catheters and prosthetics, leading to many complications. Several approaches are under investigation to combat drug-resistant bacteria. Deployment of bacteriophages is one of the promising approaches to invade biofilm that may expose bacteria to the conditions adverse for their growth. Penetration into these biofilms and their destruction by bacteriophages is brought about due to their small size and ability of their progeny to diffuse through the bacterial cell wall. The other mechanisms employed by phages to infect biofilms may include their relocation through water channels to embedded host cells, replication at local sites followed by infection to the neighboring cells and production of depolymerizing enzymes to decompose viscous biofilm matrix, etc. Various research groups are investigating intricacies involved in phage therapy to mitigate the bacterial infection and biofilm formation. Thus, bacteriophages represent a good control over different biofilms and further understanding of phage-biofilm interaction at molecular level may overcome the clinical challenges in phage therapy. The present review summarizes the comprehensive details on dynamic interaction of phages with bacterial biofilms and the role of phage-derived enzymes - endolysin and depolymerases in extenuating biofilms of clinical and medical concern. The methodology employed was an extensive literature search, using several keywords in important scientific databases, such as Scopus, Web of Science, PubMed, ScienceDirect, etc. The keywords were also used with Boolean operator "And". More than 250 relevant and recent articles were selected and reviewed to discuss the evidence-based data on the application of phage therapy with recent updates, and related potential challenges.

Antibacterial and Anti-Biofilm Activities of Essential Oil Compounds against New Delhi Metallo-β-Lactamase-1-Producing Uropathogenic Klebsiella pneumoniae Strains

The World Health Organization points out that the opportunistic pathogen Klebsiella pneumoniae that causes various infections among others, urinary tract infections (UTIs), is one of the high-priority species due to a global problem of antimicrobial resistance. The aim of this study was to investigate antibacterial and anti-biofilm activities of chosen constituents of essential oils against NDM-1-producing, uropathogenic K. pneumoniae strains. The genes encoding lipopolysaccharide (uge, wabG), adhesin gene fimH (type I fimbriae) and gene encoding carbapenemase (blaNDM-1) for all tested strains were detected by PCR amplification. The K. pneumoniae ATCC BAA-2473 reference strain was uge- and blaNDM-1-positive. The effectiveness of fifteen essential oil compounds (EOCs) (linalool, β-citronellol, linalyl acetate, menthone, (−)-menthol, (+)-menthol, geraniol, eugenol, thymol, trans-anethole, farnesol, β-caryophyllene, (R)-(+)-limonene, 1,8-cineole, and carvacrol) was assessed by determining the MIC, MBC, MBC/MIC ratio against K. pneumoniae strains by the microdilution method. Anti-biofilm properties of these compounds were also investigated. Thymol, carvacrol and geraniol exhibited the best antibacterial and anti-biofilm activities against uropathogenic NDM-1-producing K. pneumoniae isolates. Results of our investigations provide a basis for more detailed studies of these phytochemicals on their application against uropathogenic K. pneumoniae.

Lipid A-Ara4N as an alternate pathway for (colistin) resistance in Klebsiella pneumonia isolates in Pakistan

Objectives

This study aimed to explore mechanism of colistin resistance amongst Klebsiella pneumoniae isolates through plasmid mediated mcr-1 gene in Pakistan. Carbapenem and Colistin resistant K. pneumoniae isolates (n  = 34) stored at − 80 °C as part of the Aga Khan University Clinical Laboratory strain bank were randomly selected and subjected to mcr-1 gene PCR. To investigate mechanisms of resistance, other than plasmid mediated mcr-1 gene, whole genome sequencing was performed on 8 clinical isolates, including 6 with colistin resistance (MIC  >  4 μg/ml) and 2 with intermediate resistance to colistin (MIC  >  2 μg/ml).

Results

RT-PCR conducted revealed absence of mcr-1 gene in all isolates tested. Whole genome sequencing results revealed modifications in Lipid A-Ara4N pathway. Modifications in Lipid A-Ara4N pathway were detected in ArnA_ DH/FT, UgdH, ArnC and ArnT genes. Mutation in ArnA_ DH/FT gene were detected in S3, S5, S6 and S7 isolates. UgdH gene modifications were found in all isolates except S3, mutations in ArnC were present in all except S1, S2 and S8 and ArnT were detected in all except S4 and S7. In the absence of known mutations linked with colistin resistance, lipid pathway modifications may possibly explain the phenotype resistance to colistin, but this needs further exploration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05867-3.