Water Pollution and its Impact on the Prevalence of Antibiotic-Resistant E-coli and Total Coliform Bacteria: A Study of the Semenyih River, Peninsular Malaysia

Recently the antibiotic-resistant bacteria have increased in environment, creating a worldwide impact on both public and environmental health. The purpose of this study is to investigate the prevalence of antibiotic resistant E. coli and total coliform bacteria in the Semenyih River, and to determine the influence of water contamination on the distribution of antibiotic resistant E. coli and total coliform bacteria. Water samples were collected from 8 stations along the river during April, July, September, and November 2013. The antibiotic resistance of the bacterial isolates to 6 antibiotics was tested using the disk-diffusion method and water quality parameters were also determined such as dissolved oxygen, temperature, pH, conductivity, nitrate (NO3), phosphate (PO4), ammonia nitrogen (NH3-N), total suspended solids, biochemical oxygen demand, chemical oxygen demand, E. coli and total coliform. From the 640 E. coli isolates, 81.1 % exhibited resistance to ampicillin, 96.4 % to penicillin, 31.9 % to gentamicin, 48 % to tetracycline, 9.7 % to ciprofloxacin and 25.6 % were resistant to chloramphenicol. In contrast, the 640 isolates of total coliform were 80.5 % resistant to ampicillin, 96.4 % to penicillin, 30.8 % to gentamicin, 47.8 % to tetracycline, 7.7 % to ciprofloxacin and 22 % exhibited resistance to chloramphenicol. Significant differences in antibiotic resistance were found among sampling stations (ANOVA, p < 0.05). Significant statistical variations also were found among sampling stations for all water quality variables measured (ANOVA, p < 0.05) except conductivity that showed no significant differences among sampling stations (ANOVA, p > 0.05). These results suggest that antibiotic resistance may be related to water quality declined due to untreated sewage from rural areas, domestic wastewater, intensive agricultural and industrial activities, livestock farms, and urban runoff.