Plasmid Profiling and Occurrence of β-Lactamase Enzymes in Multidrug-Resistant Uropathogenic Escherichia coli in Kathmandu, Nepal

Abstract

Introduction

Extended-spectrum β-lactamases (ESBL) among Gram-negative bacteria, predominantly Escherichia coli (E. coli), in Nepal, have been rising. The main objectives of this study were to determine the prevalence of uropathogenic E. coli, antibiotic resistance, ESBLs, ABLs (AmpC type β-lactamases), MBLs (metallo-β-lactamases) and KPCs (Klebsiella pneumoniae carbapenemases) and their correlation with plasmid profiling patterns among patients with urinary tract infections in a tertiary hospital in Kathmandu, Nepal.

Methods

The mid-stream urine samples collected from patients were inoculated in cystine–lactose–electrolyte-deficient (CLED) agar plates. E. coli producing ESBLs, ABLs, MBLs/KPC were identified phenotypically using standard microbiological methods. Plasmids were extracted by alkaline lysis method from E. coli isolates and profiled using agarose gel electrophoresis.

Results

Out of the total 2661 urine samples, E. coli were isolated in 64.34% (507/788), among which 170 (33.53%) were multidrug-resistant (MDR) isolates. All MDR isolates were resistant to amoxicillin and third-generation cephalosporins but were highly sensitive to imipenem (94.12%, 160/170), amikacin (92.94%, 158/170) and nitrofurantoin (86.47%, 147/170). Among 170 MDR isolates, 78.2% (133/170) were ESBLs, 46.3% (50/170) were AmpC, 11.2% (19/170) were MBL and 0.6% (1/170) were KPC producers. Coproduction of β-lactamases was detected in 24.12% (41/170) of isolates. E. coli isolates showed one plasmid (>33.5 kb), which was present in all the isolates. Overall, 44 different plasmid profile groups were identified based on molecular weight and number of plasmids. β-Lactamase producers were relatively resistant to the higher number of antibiotics tested (≤10) than non-producers (≤8), and the number of plasmids were higher in β-lactamase producers (≤7) than those in non-producers (≤5).

Conclusion

The higher prevalence of the ESBLs, AmpCs, KPCs and MBLs along with their coproduction in E. coli isolates highlights the importance of routine surveillance of ESBLs, AmpCs, KPCs and MBLs in microbiology laboratories using various phenotypic methods.

Keywords:

• uropathogenic Escherichia coli
• antibiotic resistance
• ESBL
• extended-spectrum β-lactamases
• AmpC type β-lactamases
• MBL
• metallo-β-lactamases
• KPC
• Klebsiella pneumoniae carbapenemases

Acknowledgments

The authors would like thank Kantipur College of Medical Science and Kathmandu Model Hospital for providing an opportunity to conduct this study. The authors are also grateful to all the patients and technical staff for their help during the study. We would like to express our gratitude to Mr. Gordon Tambellini, USA, for proof reading and edits.

Abbreviations

AmpCs BL, AmpC type β-lactamases; AST, antibiotic susceptibility test; ATCC, American Type Culture Collection; CLED, cystine–lactose–electrolyte-deficient agar; CLSI, Clinical and Laboratory Standard Institute; EDTA, ethylene diamine-tetraacetic acid; ESBL, extended-spectrum β-lactamase; IPD, inpatients department; KMH, Kathmandu Model Hospital; KPCs, Klebsiella pneumoniae carbapenemases; MBLss, metallo-β-lactamase; MDR, multidrug-resistant; MHA, Mueller Hinton Agar; MSU, mid-stream urine; NDM, New Delhi metallo β-lactamase; OPD, outpatients department; PBP, phenyl boronic acid; UTI, urinary tract infection; WHO, World Health Organization.

Data Sharing Statement

All data pertaining to this study are within the manuscript.

Ethical Approval and Consent

This study was ethically approved from institutional review committee (IRC); phect-NEPAL. A written informed consent was obtained from each patient before their participation and collection of samples. In the case of illiterate participants, information was provided by reading the consent form in the presence of witnesses.

Author Contributions

All authors contributed to data analysis, drafting and revising the article, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no competing interests.