Antibiotic resistance profiles of environmental isolates from Mhlathuze River, KwaZulu-Natal (RSA)

One hundred and thirteen enteric bacteria were isolated from the Mhlathuze River during February 2001 to January 2002. The antibiotic resistance patterns (ARPs) of these identified isolates showed that 94.7 % were resistant to at least one class of antibiotic while 75.2% were multi-resistant. All isolates were sensitive to gentamicin. The levels of resistance exhibited by isolates to specific antibiotics are as follows: penicillin, 72.6%; rifampicin, 69.2%; novobiocin, 52.1%; ampicillin, 43.6% and cephalothin, 28.2 %. The antibiotic resistance gene pool especially that for β-lactamase is likely to be widely available in the environment. The ARPs for E. coli and non-E. coli groups were very similar. The enteric bacteria isolated from downstream, which is a mainly urban and industrial area, were more resistant to several antibiotics than those from upstream which is predominantly rural. The results suggest that environmental, industrial and/or human activities impact on the level of antibiotic resistance in the environment. The strong correlation (r=0.97) between the ARPs of the clinical and the environmental isolates may suggest a link between diarrhoeal incidence and the water quality in the region. It is thus imperative that the determination of antibiotic susceptibility/resistance patterns of isolated microbes is a part of the microbial monitoring process of the water.