Extended spectrum beta-lactamase encoding gene-fingerprints in multidrug resistant <i>Escherichia coli</i> isolated from wastewater and sludge of a hospital treatment plant in Nigeria

Abstract

This study investigated the occurrence of Extended Spectrum Beta-Lactamase (ESBL) genes in ESBL- producing Escherichia coli isolated from wastewater and sludge of a tertiary hospital treatment plant. Wastewater (treated and untreated) and sludge were collected over a period of four months for the isolation of E. coli on CHROMagar E. coli amended with 6 μg/mL of cefotaxime. The identity of the bacteria was confirmed by detection of uidA gene. Screening for ESBL production was done using the Double Disc Synergy Method (DDST). Detection of ESBL genes was done using quantitative PCR. Antibiotic susceptibility testing was carried out using the disc diffusion method. A total of thirty-three distinct E. coli were obtained with twelve being ESBL producers. blaTEM, blaCTX-M-2, blaCTX-M-8 and blaCTX-M-25 were detected in eight isolates. All the ESBL- producing E. coli harboured blaCTX−M-1 and blaCTX−M-9. blaCMY−1 was detected in one of the twelve ESBL- producers. There was 100% resistance to tetracycline, sulphonamide, ertapenem, cefpodoxime and cefotaxime, and 75% showing resistance to ciprofloxacin, ceftazidime and amoxycillin-clavulanate respectively in the ESBL positive isolates.