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Southport, Australia

Gundogdu A.,University of The Sunshine Coast | Jennison A.V.,Public Health Microbiology | Smith H.V.,Public Health Microbiology | Stratton H.,Griffith University | And 3 more authors.
Canadian Journal of Microbiology | Year: 2013

We investigated the prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in untreated hospital wastewaters and 2 sewage treatment plants (STPs). A collection of 252 ESBL-producing E. coli isolates from hospital wastewater and STPs were typed and tested for resistance to 17 antimicrobial agents and for the presence of integron-associated integrases (intI gene) and ESBL genes. Eighty-nine percent (n = 176) of the ESBL-producing E. coli strains from hospital wastewater were found in more than 1 sample (common types), with 1 common type accounting for 35% of isolates, found in all samples. These strains were also resistant to up to 9 non-β-lactam antibiotics and showed the same pattern of resistance in all samples. More than 73% of the hospital wastewater isolates possessed SHV-type ESBL as opposed to isolates from STPs that carried only CTX-M-type ESBL genes. The prevalence of the intI gene did not differ between the sources of the isolates. Certain ESBL-producing E. coli were dominant in hospital wastewaters. These strains possessed β-lactamase genes that were different from isolates found in STPs. From a public health point of view, the presence of such a high level of ESBL-producing E. coli strains in hospital wastewaters is of great importance.

Thompson J.M.,University of The Sunshine Coast | Gundogdu A.,University of The Sunshine Coast | Stratton H.M.,Griffith University | Stratton H.M.,Smart Water Research Center | And 2 more authors.
Journal of Applied Microbiology | Year: 2013

Aims: To investigate the presence of methicillin-resistant Staphylococcus aureus (MRSA) in untreated hospital wastewaters (UHWW), their transmission into the receiving sewage treatment plant (STP) and survival through the STP treatment. Methods and Results: Over eight consecutive weeks of sampling, we isolated 224 Staph. aureus strains from UHWW-1, UHWW-2 and its receiving STP inlet (SI) and post-treatment outlet (SO). These strains were typed using the PhP typing method and RAPD-PCR and tested for their antibiotic resistance patterns. Resistance to cefoxitin and the presence of mecA gene identified MRSA isolates. In all, 11 common (C) and 156 single (S) PhP-RAPD types were found among isolates, with two multidrug resistant (MDR) C-types found in H2, SI and SO. These C-type strains also showed resistance to cefoxitin and vancomycin. The mean number of antibiotics to which the strains from UHWW were resistant (5·14 ± 2) was significantly higher than the STP isolates (2·9 ± 1·9) (P < 0·0001). Among the 131 (68%) MRSA strains, 24 were also vancomycin resistant. MDR strains (including MRSA) were more prevalent in hospital wastewaters than in the STP. Conclusion: This study provides evidence of the survival of MRSA strains in UHWWs and their transit to the STP and then through to the final treated effluent and chlorination stage. Significance and Impact of the Study: This preliminary study identifies the need to further investigate the load of MRSA in hospitals' wastewaters and possible their survival in STPs. From a public health point of view, this potential route of hospital MRSA dissemination is of great importance. © 2012 The Society for Applied Microbiology.

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