Diversity of Extended Spectrum Beta-lactamase (ESBL) genes in Escherichia coli isolated from wastewater generated by a Sick Bay located in a University Health Care Facility

Background

Antibiotic resistance is an ill which has ravaged so many countries of the world, the worst hit being African countries. This study investigated the occurrence of extended spectrum beta-lactamase producing E. coli and their genes in wastewater generated by the sick bay of a University Health Centre Facility.

Methods

Wastewater from three channels in the sick bay 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. Molecular characterization of the isolates was done by detecting the presence of uidA gene. Screening for ESBL production was done using Double Disk Synergy Method, and antibiotic susceptibility testing was done using the disc diffusion method. Detection of ESBL genes was done using quantitative PCR.

Results

Twenty-four ESBL positive E. coli possessing the uidA gene were obtained from a pool of thirty-eight E. coli obtained There was 100% resistance to sulfonamide, ertapenem, cefpodoxime and cefotaxime by the isolates, while the resistance to tetracycline was 87.5%, ciprofloxacin (20.8%), ceftazidime (75.0%) and amoxicillin-clavulanate (58.3%). The twenty-four isolates possessed bla_CTX-M-1 and bla_CTX-M-9, with fourteen possessing bla_CTX-M-2, bla_CTX-M-8 and bla_CTX-M-25. Nineteen isolates harboured bla_TEM, while bla_CMY-1 was detected in five isolates. One isolate possessed ampC gene. bla_KPC, bla_NDM-1 and bla_SHV were not detected in any isolate.

Conclusion

There is a need for adequate treatment of wastewater from hospital/clinical settings to prevent a public health breakdown as a result of the discharge of untreated wastewater laden with antibiotic resistant bacteria and their genes into the environment.