Environmental Antimicrobial Resistance (En-Amr) in Surface Water of Thiruvananthapuram City, Kerala

Aim: The study was done to understand the microbial contamination and antibiotic resistance pattern in surface water environment.

Study Area and Sampling: Water samples collected from selected water bodies in the main urban area of Thiruvananthapuram were analysed for the presence of coliforms and the pattern of antimicrobial resistance in bacterial cultures isolated from the water samples.

Methodology: The total coliform count and faecal coliform count was determined using the multiple tube fermentation technique and the total heterotrophic bacterial count was performed using nutrient agar media. The bacterial cultures were identified using biochemical characterization and Antibiotic susceptibility patterns for the various bacterial isolates were determined using commercial antibiotic disks (Hi Media, Mumbai) in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines by Kirby-Bauer disc diffusion method. The antibiotics used were Ampicillin, Chloramphenicol, Ciprofloxacin, Gentamicin, Tetracycline and Meropenem. Multiple Antibiotic resistances (MAR) index was determined for those isolates which showed resistance to more than three antibiotics.

Results: The total heterotrophic bacteria, total coliforms and fecal coliforms were significantly high in all the sites, indicating that the water bodies are sewage contaminated. The biochemical identification of bacterial strains isolated from water sample showed the presence of E. coli, Bacillus sp, Staphylococcus sp, Klebsiella sp, Clostridium sp, Neisseria sp, Enterobacter sp, Enterococcus sp and Streptococcus sp in varying frequencies in different sites. Among these 58 isolates, 26 strains were found to be resistant against 3 or more antibiotics and hence, designated as multi drug resistant. The isolates were highly resistant to Ampicillin (98%), Chloramphenicol (53%) and Gentamycin (44%); and highly susceptible to Meropenem (86%), Ciprofloxacin (69%) and Tetracyclin (58%). E. coli showed maximum resistance to all the antibiotics. One- way ANOVA of the obtained data revealed that there is no significance difference in spatial distribution of antibiotic resistance.