Trends in antimicrobial resistance of bacterial isolates circulating in sewage waters of Aligarh region over a period of 14 years

Antibacterial-resistant pathogens are serious threat worldwide. The presence of drug-resistant bacteria in environmental samples has important implications for people living in the area who are reliant on public water and sanitation facilities. Detection of faecal indicator bacteria in water provides a very sensitive method of quality assessment. This study was designed to compare the prevalence of gram-negative bacteria circulating in sewer lines of Aligarh region at an interval of every four to five years. This study was conducted in the department of Microbiology, JN Medical College and Hospital over a period of fourteen years. Trends of antimicrobial susceptibility were assessed over this period. Isolates resistant to any of the 3rd generation cephalosporins were also evaluated for the presence of extended spectrum β-lactamases, Amp-C and metallo-β-lactamases. Escherichia coli was the commonest coliform isolated throughout the 14-year study period. Polymicrobial growth was more common in 2005 and 2013. Increase in the antimicrobial resistance was noted among the bacterial strains isolated in the last eight years of study. Isolation of ESBL and Amp-C producing bacterial isolates in sewage waters was the most alarming finding. Circulation of antimicrobial resistant bacteria in the environment is an alarming indicator of the rampant use of antibiotics. It is suggested that periodic surveys should be done to study the prevalence and susceptibility pattern of environmental water samples.