Molecular Characterization of Extended Spectrum β-lactamase and Carbapenemase Producing Klebsiella pneumoniae from a Tertiary Care Hospital

Molecular detection of extended-spectrum β-lactamase- and carbapenemase-producing Klebsiella pneumoniae isolates in southwest Iran

OBJECTIVE

The global emergence of carbapenem-resistant Klebsiella pneumoniae is considered a significant contemporary concern., as carbapenems are the last resort for treating infections caused by multidrug-resistant Gram-negative bacteria. This study aimed to investigate the carbapenem-resistance genes in extended-spectrum β-lactamase producing K. pneumoniae isolates.

METHODS

Seventy-five non-duplicate clinical K. pneumoniae strains were isolated from urine, blood, sputum, and wound samples. Antimicrobial susceptibility tests for 12 different antibiotics were performed using the disk diffusion method, followed by determining minimum inhibitory concentrations of imipenem and meropenem. Phenotypic detection of extended-spectrum β-lactamase and carbapenemase enzymes was performed by double-disc synergy test and modified Hodge test, respectively. PCR assay further investigated resistant isolates for extended-spectrum β-lactamase and carbapenemase-encoding genes.

RESULTS

The highest and lowest resistance rates were observed against ampicillin (93.3%) and tigecycline (9.3%). According to phenotypic tests, 46.7% of isolates were positive for extended-spectrum β-lactamase enzymes and 52.8% for carbapenemase. A total of 11 isolates contained carbapenemase genes, with blaOXA-48 (19.4%; 7/36) being the predominant gene, followed by blaNDM (8.3%; 3/36).

CONCLUSION

The study's findings reveal the alarming prevalence of beta-lactamase enzymes in K. pneumoniae strains. Early detection of carbapenem-resistant isolates and effective infection control measures are necessary to minimise further spread, as carbapenem resistance has become a public health concern.

Drug Resistance Genes and Molecular Epidemiological Characteristics of Carbapenem-Resistant Klebsiella pneumonia

Background

The global prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a serious challenge for nosocomial infection and attracted worldwide attention. This study explored the drug resistance genes and molecular characteristics for CRKP, providing a reference for nosocomial prevention and control.

Methods

A total of 42 CRKP isolates were collected from the First Affiliated Hospital of Gannan Medical University (Ganzhou, China) from January 2018 to February 2021. The drug resistance of CRKP was tested by the VitekII Compact system. Drug resistance gene expression was detected by poly-merase chain reaction (PCR), and molecular typing was performed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST).

Results

All the 42 CRKP isolates were multi-drug resistant. Among them, 35 isolates (83.3%) produced bla_KPC-2 and 12 isolates (28.6%) produced bla_NDM-1. The detection rate of bla_IMP-4 and bla_OXA-48 was 2.4% (1/42), respectively. Twelve isolates (28.6%) carried both bla_KPC-2 and bla_NDM-1, one isolate (2.4%) carried both bla_KPC-2 and bla_IMP-4, and one isolate (2.4%) carried bla_KPC-2, bla_NDM-1 and bla_OXA-48. A variety of other extended-spectrum beta-lactamases (ESBLs) were also detected. All 42 isolates carried bla_SHV and bla_CTX-M-1, 27 isolates (64.3%) carried bla_TEM and 12 isolates (28.6%) carried bla_CTX-M-9. The MLST data classified the 42 CRKP isolates into 11 sequence types, mainly ST11, accounting for 61.9% (26/42), of which 92.3% of isolates (24/26) carrying bla_KPC-2. The PFGE results demonstrated that the 42 CRKP isolates could be divided into 20 clusters A-T, with cluster A (26.2%, 11/42) and cluster H (21.4%, 9/42) dominating, which were all ST11.

Conclusion

The CRKP isolates were severely multi-drug resistant, and the main resistant gene was bla_KPC-2 production, carrying multiple ESBLs genes simultaneously. The MLST and PFGE revealed that the ST11-bla_KPC-2 Klebsiella pneumoniae was the main clonotype. Our findings may offer help to antibiotics selection and nosocomial infection prevention and control.

Exploring the Antibiotic Resistance Profile of Clinical Klebsiella pneumoniae Isolates in Portugal

While antibiotic resistance is rising to dangerously high levels, resistance mechanisms are spreading globally among diverse bacterial species. The emergence of antibiotic-resistant Klebsiella pneumoniae, mainly due to the production of antibiotic-inactivating enzymes, is currently responsible for most treatment failures, threatening the effectiveness of classes of antibiotics used for decades. This study assessed the presence of genetic determinants of β-lactam resistance in 102 multi-drug resistant (MDR) K. pneumoniae isolates from patients admitted to two central hospitals in northern Portugal from 2010 to 2020. Antimicrobial susceptibility testing revealed a high rate (>90%) of resistance to most β-lactam antibiotics, except for carbapenems and cephamycins, which showed antimicrobial susceptibility rates in the range of 23.5−34.3% and 40.2−68.6%, respectively. A diverse pool of β-lactam resistance genetic determinants, including carbapenemases- (i.e., blaKPC-like and blaOXA-48-like), extended-spectrum β-lactamases (ESBL; i.e., blaTEM-like, blaCTX-M-like and blaSHV-like), and AmpC β-lactamases-coding genes (i.e., blaCMY-2-like and blaDHA-like) were found in most K. pneumoniae isolates. blaKPC-like (72.5%) and ESBL genes (37.3−74.5%) were the most detected, with approximately 80% of K. pneumoniae isolates presenting two or more resistance genes. As the optimal treatment of β-lactamase-producing K. pneumoniae infections remains problematic, the high co-occurrence of multiple β-lactam resistance genes must be seen as a serious warning of the problem of antimicrobial resistance.

Distribution and genetic diversity of multi-drug-resistant Klebsiella pneumoniae at the human–animal–environment interface in Pakistan

Klebsiella pneumoniae is ubiquitous and known to be a notorious pathogen of humans, animals, and plant-based foods. K. pneumoniae is a recognized trafficker of antibiotic resistance genes (ARGs) between and from different ecological niches. A total of 775 samples (n = 775) were collected from September 2017 to August 2019 from humans, animals, and environmental sources by applying the random convenient sampling technique. A total of 120 (15.7%) samples were confirmed as K. pneumoniae. The distribution of K. pneumoniae among humans, the environment, and animals was 17.1, 12.38, and 10%, respectively. Isolates have shown significant resistance against all the subjected antibiotics agents except colistin. ARGs profiling revealed that the highest percentage prevalence (67.5%) of bla_CTX–M was estimated in the isolates, and various carbapenem resistance genes that were found in the study were bla_NDM–1 (43.3%), bla_OXA–48 (38%), and (1.67%) bla_KPC–2. Overall, 21 distinct sequence types (ST) and 13 clonal complexes (CCs) were found through the multi-locus sequence typing (MLST) analysis. Taking together, the distribution of multi-drug resistance (MDR) K. pneumoniae clones in the  community and associated environment is alarming for the health care system of the country. Health policymakers should consider the role of all the integral parts of humans, animals, and the associated environment intently to cope with this serious public and animal health concern.

Comparative Evaluation of Colistin Broth Disk Elution Method With Two Commercially Available Systems for Colistin Susceptibility Testing Against Carbapenem-Resistant Klebsiella pneumoniae: A Single-Center Exploratory Study

Purpose: The purpose is to explore the diagnostic utility of colistin broth disk elution (CBDE) as a simple and reliable method of colistin susceptibility testing.

Materials and methods: An exploratory study was undertaken in a tertiary care teaching hospital in Uttarakhand, from September 2021 to March 2022, after obtaining approval from the Institute Ethics Committee. Twenty-five non-repetitive carbapenem-resistant Klebsiella pneumoniae clinical isolates were included in the study. Matrix‐assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and BD Phoenix M50 system were used to perform species-level identification and antibiotic susceptibility testing (AST), respectively, as per the manufacturer’s instructions. AST results (including those of colistin) were interpreted as per the CLSI guidelines 2022. The test isolates were further subjected to additional in vitro colistin susceptibility testing using a commercially available Mikrolatest colistin susceptibility testing kit and CBDE, respectively.

Results: The in vitro colistin resistance rates varied from 8% by BD Phoenix system to 20% by Mikrolatest kit and 32% by CBDE, respectively. For colistin susceptibility, a higher CA was observed between the BD Phoenix system and CBDE (64.71%) than between the Mikrolatest kit and CBDE (31.60%). Overall, a statistically significant fair agreement was observed between the BD Phoenix system and CBDE (Kappa: 0.312; 95% CI: 0.036 to 0.660) and Mikrolatest MIC colistin kit and CBDE (Kappa: 0.286; 95% CI: 0.111 to 0.683), respectively.

Conclusions: In vitro colistin testing remains a significant challenge globally. Although the present study results are inconclusive due to the small sample size, we should conduct multi-centric studies globally, taking a considerable sample size representing different Gram-negative bacilli to generate conclusive evidence on the utility of CBDE as a reliable method of colistin susceptibility testing.

Influence of Antimicrobial Stewardship and Molecular Rapid Diagnostic Tests on Antimicrobial Prescribing for Extended-Spectrum Beta-Lactamase- and Carbapenemase-Producing Escherichia coli and Klebsiella pneumoniae in Bloodstream Infection

The objective of this study was to evaluate whether the addition of the Verigene BC-GN molecular rapid diagnostic test to standard antimicrobial stewardship practices (mRDT + ASP) decreased the time to optimal and effective antimicrobial therapy for patients with extended-spectrum beta-lactamase (ESBL)- and carbapenemase-producing Escherichia coli and Klebsiella pneumoniae bloodstream infections (BSI) compared to conventional microbiological methods with ASP (CONV + ASP). This was a multicenter, retrospective cohort study evaluating the time to optimal antimicrobial therapy in 5 years of patients with E. coli or K. pneumoniae BSI determined to be ESBL- or carbapenemase-producing by mRDT and/or CONV. Of the 378 patients included (mRDT + ASP, n = 164; CONV + ASP, n = 214), 339 received optimal antimicrobial therapy (mRDT + ASP, n = 161; CONV + ASP, n = 178), and 360 (mRDT + ASP, n = 163; CONV + ASP, n = 197) received effective antimicrobial therapy. The mRDT + ASP demonstrated a statistically significant decrease in the time to optimal antimicrobial therapy (20.5 h [interquartile range (IQR), 17.0 to 42.2 h] versus 50.1 h [IQR, 27.6 to 77.9 h]; P < 0.001) and the time to effective antimicrobial therapy (15.9 h [IQR, 1.9 to 25.7 h] versus 28.0 h [IQR, 9.5 to 56.7 h]; P < 0.001) compared to CONV + ASP, respectively. IMPORTANCE Our study supports the additional benefit of molecular rapid diagnostic test in combination with timely antimicrobial stewardship program (ASP) intervention on shortening the time to both optimal and effective antimicrobial therapy in patients with ESBL- or carbapenemase-producing Escherichia coli and Klebsiella pneumoniae bloodstream infections, compared to conventional microbiological methods and ASP. Gram-negative infections are associated with significant morbidity and mortality, often resulting in life-threatening organ dysfunction. Both resistance phenotypes confer resistance to many of our first-line antimicrobial agents with carbapenemase-producing Enterobacterales requiring novel beta-lactam and beta-lactamase inhibitor combinations or other susceptible non-beta-lactam antibiotics for treatment. National resistance trends in a cohort of hospitalized patients at U.S. hospitals during our study period demonstrate the increasing incidence of both resistance phenotypes, reinforcing the generalizability and timeliness of such analysis.

Prevalence and antimicrobial susceptibility of extended-spectrum beta lactamases-producing Escherichia coli and Klebsiella pneumoniae isolated in selected hospitals of Anyigba, Nigeria

BACKGROUND

Escherichia coli and Klebsiella pneumoniae are commonly implicated in urinary tract infections accounting for majority of the antimicrobial resistance encountered in hospitals.

OBJECTIVES

To determine the prevalence and antimicrobial susceptibility of extended-spectrum beta-lactamases (ESBLs) producing E. coli and K. pneumoniae among patients in Anyigba, Nigeria.

METHODS

This hospital-based cross-sectional study was conducted using urine samples from 200 patients of Grimmard Catholic hospital and Maria Goretti hospital. Urine samples were processed to identify ESBL-producing E. coli and K. pneumoniae using standard microbiological techniques. Isolates were then tested against antimicrobial agents.

RESULTS

A total of 156 bacterial isolates were recovered consisting 128 of E. coli and 28 of K. pneumoniae. Extended spectrum beta-lactamases production was observed in 69% of E. coli and 31% of K. pneumoniae. These pathogens were resistant to 3 or more antibiotics. Of the antimicrobials tested, cefotaxime demonstrated the highest rates of resistance (100%) for both ESBL-producing E. coli and K. pneumoniae. Fifty-four isolates of ESBL-producing E. coli showed a high level of resistance to amoxicillin clavulanic acid (83.3%), ciprofloxacin (83.3%), and ceftazidime (79.6%). ESBL-positive K. pneumoniae isolates were highly resistant to ciprofloxacin (75%), and amoxicillin clavulanic acid (83.3%). Cefoxitin (62.5%) and gentamicin (66.7%) showed substantially higher rates of resistance against these isolates while all 24 strains were resistant to imipenem.

CONCLUSION

This study indicated the prevalence of ESBL-positive Gram-negative pathogens in these study sites and also demonstrated their resistance to a few antibiotics. This highlights the need for new antimicrobials that are potent and improved policy on use of antibiotics.

Molecular insights of Carbapenem resistance Klebsiella pneumoniae isolates with focus on multidrug resistance from clinical samples

BACKGROUND

Carbapenem are the last-line antibiotic, defence against Gram-negative extended spectrum ß-lactamases producers (ESBLs). Carbapenem resistance Enterobacteriaceae especially Carbapenem resistant-Klebsiella pneumoniae (CR-KP) is recognized as one of the well-known public health problem, which is increasingly being reported around the world. The present study was focused to analyse the prevalence and characterization of antibiotic resistance K. pneumoniae in centre region of Tamil Nadu, India.

METHODOLOGY

Totally 145 suspected K. pneumoniae isolates [Urine, Pus, Sputum, Blood and Biopsy] obtained from hospitals of Central South India. The isolates were subjected to biochemical and molecular identification technique, following with antibiotic resistance pattern by standard antibiotic sensitivity test. Multidrug resistance (MDR) with β-lactamase producing Carbapenem resistant K. pneumoniae (CR-KP) strains were screened by classical sensitivity method and also drug resistance encoded gene. Also, molecular typing of the MDR strains were characterized by Pulsed-Field Gel Electrophoresis (PFGE). Further, the outer membrane protein (OmpK35 and 36) related Carbapenem resistance were characterized.

RESULTS

Totally, 61% of isolates were confirmed as K. pneumoniae, 75 % of isolates were MDR including 58% carbapenem and 97% ESBL antibiotics and grouped into 17 distinct resistant patterns. The MDR KP isolates shows positive for blaCTXM-1 (92 %) gene followed by blaSHV (43 %), blaTEM (36 %), blaNDM-1 (26 %), blaGES (20 %) and blaIMP-1 (8 %). Moreover, 62 % CR-KP isolates loses OmpK36 and 33% isolates loses OmpK35.

CONCLUSIONS

Loss of OmpK36 were highly an influence the cefoxitin and carbapenem resistance. Sixteen different PFGE patterns have been observed among the 18 MDR isolates. Eventually, ESBL as well as CR-KP were diverse in genetic makeup and often associated with hyper virulence hvKP should be of serious concern.

Detection and Control of Biofilm Formation by Staphylococcus aureus from Febrile Neutropenic Patient

INTRODUCTION

Febrile neutropenia (FN) is the evolution of fever in a patient with neutropenia over 38.0°C. Neutropenia is diagnosed when absolute neutrophil count (ANC) <1500 cells/µL. FN represents a common complication of cancer treatment. Hence, it is featured to be a major cause of morbidity and mortality in cancer patients. Staphylococcus aureus is one of the most important microorganisms isolated from the blood of febrile neutropenic patients. Infections caused by S. aureus range from mild to life-threatening diseases. Biofilm production by S. aureus is one of the most significant virulence factors of the bacterium as it prevents the penetration of antibiotics. Recently, it has been shown that S. aureus carries the ica operon responsible for biofilm production. The aim of the work is to determine a genotypic characterization that includes not only the detection of icaA and icaD genes in S. aureus but also the determination of their relation to clinical and microbiological features. Empiric antibacterial treatment was recommended for cancer patients receiving chemotherapy.

MATERIALS AND METHODS

The relation between the presence of icaA and icaD and biofilm production was determined in a collection of 66 S. aureus samples from febrile neutropenic patients. Biofilm-forming ability was tested on Congo Red agar plates. Also, the effect of the most sensitive antibiotics on the bacterial cells was determined by an electron microscope.

RESULTS

Of the bacterial samples, 48 were biofilm-productive and 18 were non-biofilm productive. For the biofilm productive bacteria, 37.5% were positive for icaA, 22.9% were positive for icaD and 10.4% were positive for both. Linezolid was the most effective antibiotic and it is highly recommended for the treatment of febrile neutropenia caused by biofilm-productive S. aureus. Severe changes were found on the bacterial cell after being treated with Linezolid. The icaA and icaD genes were present in only 50% of biofilm-productive bacteria.

CONCLUSION

The ica operon is present in only 50% of biofilm-productive S. aureus and Linezolid is the best antibiotic against these bacteria.

Evaluation of Resistance Mechanisms in Carbapenem-Resistant Enterobacteriaceae

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) is a major concern leading to morbidity and mortality in the world. CRE often is becoming a cause of therapeutic failure in both hospital and community-acquired infections.

AIM

This study aimed to investigate the resistance mechanisms of CRE by phenotypic and molecular methods.

MATERIALS AND METHODS

Sixty CRE (50 Klebsiella pneumoniae, 6 Escherichia coli, and 4 Enterobacter spp.) were isolated from October 2018 to June 2019. Antimicrobial susceptibility testing was carried out using phenotypic methods. The carbapenem resistance mechanisms including efflux pump hyperexpression, AmpC overproduction, carbapenemase genes, and deficiency in OmpK35 and OmpK36 were determined by phenotypic and molecular methods, respectively.

RESULTS

Sixty CRE (50 Klebsiella pneumoniae, 6 Escherichia coli, and 4 Enterobacter spp.) were isolated from October 2018 to June 2019. Amikacin was found to be the most effective drug against CRE isolates. All isolates were resistant to imipenem and meropenem by the micro-broth dilution. AmpC overproduction was observed in all Enterobacter spp. and three K. pneumoniae isolates. No efflux pump activity was found. Carba NP test and Modified Hodge Test could find carbapenemase in 59 (98%) isolates and 57 (95%) isolates, respectively. The most common carbapenemase gene was bla OXA-48-like (72.8%) followed by bla NDM (50.8%), bla IMP (18.6%), bla VIM (11.8%), and bla KPC (6.7%). The ompK35 and ompK36 genes were not detected in 10 and 7 K. pneumoniae isolates, respectively.

CONCLUSION

The amikacin is considered as a very efficient antibiotic for the treatment of CRE isolates in our region. Carbapenemase production and overproduction of AmpC are the main carbapenem resistance mechanisms in CRE isolates. Finally, Carba NP test is a rapid and reliable test for early detection of carbapenemase-producing isolates.