Screening of antibiotic resistant gram negative bacteria and Plasmid profiling of multi-drug resistant isolates present in sewage associated with health care centers

Abstract

Background: Healthcare effluent acts as the store house of harmful infectious agents such as the pathogens and microorganisms possessing multiple drug resistant genes. Potential health risk includes spreading of diseases by these pathogens and wide dissemination of antimicrobial resistance genes. Gram-negative bacteria are particular ly important for causing most of the hospital and community acquired infections. Aim: This study was carried out to highlight the incidence of antibiotic resistant bacteria in hospital generated effluent discharged into municipal sewage system of Sylhet city, Bangladesh. Methodology: Standard biochemical tests were used to isolate and identify 29 gram negative bacteria from 6 effluent samples . Antibiotic susceptibility test was assessed by Kirby-Bauer disc diffusion method. Plasmid isolation and gel electrophoresis were performed using standard protocols. Results: Antibiogram study showed that the percentage of isolates resistant to amoxicillin, ceftriaxone, ciprofloxacin, gentamicin, imipenem, azithromycin, andsulphamethoxazole-trimethoprim were 93.10%, 55.17%, 27.6%, 24.14%, 20.7%, 13.8% and 10.34% respectively. Ten of the isolates showed resistance to three or more commonly used antibiotics. Plasmid profiles of the multi-drug resistant isolates showed to harbor two or more plasmids and almost all of them showed a common band for plasmid DNA size of 24.5kb. Conclusion: Resistance to the bacterial pathogens causing community acquired infections may, thus, exert a serious public health threat through confining the antibiotic pool. Hospitals should follow, monitor and regulate proper sanitary measures of hospital generated effluents to forestall the dissemination of multi drug resistant bacteria transfer from hospital waste to the environment.