Antibiotic resistance bacteria in hospital wastewater

The wide application of antimicrobial agents in clinical settings to treat infectious disease, as well as their use in aquaculture and veterinary medicine, is of great concern to public health as this can lead to the development and evolution of antibiotic resistant bacteria. This research is aimed at investigating the presence and survival of antibiotic resistant bacteria in hospital wastewaters (HWW) and their transmission to the receiving sewage treatment plant (STP) and beyond. Over 8 weeks of sampling, 245 Escherichia coli and 167 Staphylococcus aureus strains were collected from HWW and its receiving STP inlet (STP-I) and posttreatment outlet (STP-O). Molecular typing of the strains showed that seven clones of multi-drug resistant (MDR) E. coli were frequently found in a majority of weekly samples of HWW. These clones were also found in STP-I and in three occasions in STP-O. Similarly, among S. aureus strains seven clones were frequently found in a majority of HWW samples with two MDR clones also found in STP-I and on two occasions in STP-O. These data suggests that some MDR bacterial strains found in HWW may have the ability to survive transmission to STP and persist throughout treatment stages of STP including chlorination before being released into surface waters. The significance of this finding for public health is not clear. Further work must be undertaken to characterize and quantify the input of MDR bacteria from hospitals compared with those originating from the community or other wastewater related sources