Multidrug resistant Escherichia coli isolated at National Public Health Laboratory, Nepal

Antimicrobial resistance in Escherichia coli is mostly associated with ß-lactamases and carbapenemases enzyme production resulting in treatment challenges. This study was conducted with the aim to detect and characterize antimicrobial resistance in E. coli isolates.

A cross-sectional study was conducted during 2018-2022, at National Public Health Laboratory where the clinical specimens (24636) received were processed for identification and characterization of antimicrobial resistance following conventional & advanced methods. Antibiotic susceptibility tests were performed by Modified Kirby Bauer disc diffusion and Minimum inhibitory concentrations using VITEK2 compact (Biomeriux). The isolates were tested for extended-spectrum ?-lactamases and Carbapenemase production following Clinical Laboratory Standards Institute guidelines.

Bacterial growth was observed in 9% (2166/24636) of the specimens, of which 44% (959) were E. coli. Among the 959 E. coli isolates, 320 were reconfirmed with VITEK-MS (Biomeriux). Phenotypic multi-drug resistance was observed in 75% (240/320) of the isolates with 62% (197/320) extended-spectrum ?-lactamases, 12% (39/320) AmpC-ß-lactamase, 10% (31/320) serine carbapenemases and 7% (22/320) Metallo-ß-lactamase while 3% (9/320) produced three types of enzymes. The extended-spectrum-?-lactamase producing E. coli were sensitive to Tigecycline (100%), Amikacin (92%), Imipenem (87%), and Meropenem (84%). Carbapenemase producers were sensitive to Tigecycline (100%), with 61% to Amikacin. Extensive-drug resistance was observed in 2% (7/320) of the isolates, with Colistin resistance in one.

The findings highlight alarmingly high antimicrobial resistance in E. coli posing significant challenges in treatment. Early detection of multi-drug resistant isolates in healthcare settings is crucial to combat antimicrobial resistance.