The presence of antibiotic resistant bacteria along the River Lagan

Antibiotic resistance (ABR) has now become a major public health issue. Relatively little work has been published on the incidence of ABR in environmental isolates within the environment, which is of importance to animal health, zoonotic transmission and human health. A study was performed to determine the diversity of total ABR (intrinsic + acquired resistance) in waterborne bacteria in a model watercourse system, namely the River Lagan, Northern Ireland, which is used a major source of drinking water by large populations of beef and dairy cattle. Total numbers of culturable bacteria at each sampling point ranged from 3.8 to 4.3 log colony forming units (cfu)/ml water, with a mean of 4. 1 ± 0.1 log cfu/ml. Total antibiotic resistance was observed to varying degrees and specific resistance levels were as follows with diminishing antibacterial effectiveness in the order: amikacin/aminoglycosides > carbapenems > fluoroquinolones > macrolides/tetracyclines/polymyxins > β-lactams/oxozolidones/rifampicin/trimethoprim/glycopeptides. Monitoring of the upstream ecology of waterways in terms of antibiotic susceptibility, from which agricultural animals gain their water, as well as the use of such water in agricultural crop irrigation is important, as well as the tracking of such organisms to their source may help determine the source of fecal pollution in aquatic ecosystems.