Prevalence and Quantitative Analysis of Antibiotic Resistance Genes (ARGs) in Surface and Groundwater in Meandering Part of the Kelani River Basin in Sri Lanka.

Abstract

Nearly 80% of the population in the Colombo district fulfill their major requirement from the Kelani river. Recent studies are interoperating: most groundwater and surface water in Sri Lanka are contaminated with waterborne pathogens and antibiotics. In the present study, nine antibiotic resistance genes (ARGs) were screened which were belonging to two common groups of antibiotic: penicillin — OPR D, bla TEM, bla OXA, amp a, and amp b — and tetracycline — tet A, tet M, tet B, and tet S. The results of the study reveled that the surface and groundwater of the entire lower part of the Kelani river basin were contaminated with TC and FC (98%). None of the penicillin and tetracycline group antibiotics were detected either surface or groundwater samples except the Kelani river mouth (amoxicillin (AMX) at 0.003 ± 0.001 µg/ml). The results showed that 5 to 15% of surface water samples were positive for penicillin resistance genes (bla TEM, bla OXA, OPR D, amp a, amp b) where ~ 10% of groundwater samples were positive against tetracycline resistance genes (tet A, tet M, tet S, tet B). Among the penicillin resistance genes, the bla TEM (700.576 × 102 copy/ml) was recorded as the highest concentration where the highest tet A gene (439.875 × 102 copy/ml) was detected among the tetracycline resistance genes. Therefore, water quality management and regular monitoring are essential to maintain the quality of drinking water in the meandering part of the Kelani river basin to safeguard river water consumers.