Plasmid Profiling and Occurrence of β-lactamase Enzymes in Multi-drug Resistant Uropathogenic Escherichia coli in Kathmandu, Nepal

Abstract Background Emergence of Extended Spectrum β-Lactamases (ESBL) among gram-negative bacteria, predominantly Escherichia coli in Nepal has been alarming. The main objectives of this study were to determine the prevalence of ESBL, ABL (AmpC type β-Lactamase), MBL (Metallo β-Lactamase) and KPC (Klebseilla pneumoniae carbapenamase) producing multi-drug resistant uropathogenic E. coli and their correlation with plasmid profiling pattern among the patients suspected of or having urinary tract infection in a tertiary hospital in Kathmandu, Nepal. Methods The mid-stream urine samples were collected from patients suspected of or having urinary tract infections (UTI) and were inoculated in Cystine Lactose electrolyte deficient (CLED) agar. The ESBL E. coli were detected by combined disc diffusion technique using cefotaxime with and without clavulanate. The isolates were screened for ABL by inhibitor-based method using cefoxitin alone and/or with cloxacillin. MBL/KPC were detected using combined-disc tests consisting of meropenem alone and with phenylboronic acid (PBA) or Ethylene diamine tetra acetic acid (EDTA), or both PBA and EDTA. Plasmids were extracted by alkaline lysis method from isolates and profiled on agarose gel electrophoresis. Results Out of total 2,661 urine samples, E. coli were isolated in 64.5% (507/788), among which 170 (33.5%) were 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 ESBL, 46.3% (50/170) were AmpC, 11.2% (19/170) were MBL and 0.6% (1/170) was 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 unanimously present in all the isolates. Overall, 44 different plasmid profile groups were identified based on the molecular weight and number of plasmids. β-lactamase producers were relatively resistant to higher number of antibiotics (≤10) than non-producer (≤8) and number of plasmids were higher in β-lactamase producers (≤7) than non-producers (≤5).