Spatial and Temporal Dynamics of Plasmid Mediated Antibiotic Resistance in Riverine Bacterial Assemblages

It is important to study the levels of antimicrobial resistance of bacteria in river water, as this will be good indicator of how effective wastewater treatment plants are in eliminating pathogenic bacteria and discouraging the development of antimicrobial resistant strains. Moreover, studying antimicrobial resistant bacteria in water environments is of utmost value because it is believed that water may provide a medium for genes to transfer from cell to cell, thereby propagating the antimicrobial resistance dilemma. The prevalence of antibiotic resistant bacteria in the river water and sediment were elucidated both spatially and temporally. Bacteria resistant to commercially available antibiotics namely, penicillin, gentamycin, amphicillin, cloxacillin, cotrimaxazole, erythromycin and tetracycline at 100, 200 and 300μg/ml were observed. The percentage of antibiotic resistant bacteria decreased, as the concentration of antibiotic increased. Statistically significant temporal and spatial variability in antibiotic resistant bacteria were observed at the sampling stations. The generic composition of the antibiotic resistant bacteria was screened. The dominant bacteria exhibiting antibiotic resistance were Klebsiella spp., Pseudomonas spp., Bacillus spp., Enterobacter spp. and Acinetobacter spp. The dissolved organic carbon (DOC)content of the water and sediment were quantified. Significant spatial and temporal variations were evident in the study stations. The occurrence of antibiotic resistant bacteria was found to be positively correlated with DOC. Furthermore, the antibiotic bacterial isolates were subjected to plasmid analysis. The plasmid profile displayed the occurrence of plasmid size > 10kb. In addition, the resistance exhibited by the riverine bacteria were found to be plasmid borne.