Abundance and Antibiotic Resistance of Escherichia coli O157:H7 Isolated from Hospital Wastewater in the Kathmandu Valley, Nepal

摘要

Hospital wastewater is prone to antimicrobial contamination and can facilitate transfer of antibiotic resistance genes (ARGs) among pathogenic bacteria. Escherichia coli O157:H7 as a reservoir or recipient of ARGs confers resistance to different antimicrobials. This study assessed the presence and antibiotic susceptibility profile of E. coli O157:H7 isolates in hospital wastewater of the Kathmandu Valley, Nepal. Seven samples were collected from six hospitals, including influent and effluent samples from one hospital with treatment facility, in February 2019. One microliter of the sample was inoculated by spread plate technique and a total of 30 isolates were identified as E. coli 0157:H7, all of which were isolated from the untreated effluents. Antibiotic susceptibility of the isolates was tested using broth microdilution method for 18 different antibiotics. The mean concentration of E. coli O157:H7 present in the samples was 3900 CFU/ml. All except for two isolates were found to be multi-drug resistant. Screening for extended-spectrum beta-lactamase (ESBL) producers and carbapenem-resistant Enterobacteriaceae (CRE) showed 29 (97%) and 7 (23%) isolates to be ESBL producers and CRE, respectively. Our findings revealed higher prevalence of antibiotic resistance in E. coli O157:H7 isolated from wastewater of hospitals and proper treatment capable of deactivating such bacteria is required.