Comparative Analysis of Antibiotic Resistance Among Escherichia coli Isolates Within Hospital Wastewater and Throughout the Urban Wastewater Process.
Mentor 1
Troy Skwor
Location
Union Wisconsin Room
Start Date
5-4-2019 1:30 PM
End Date
5-4-2019 3:30 PM
Description
Background: Annually, the United States combats two million antibiotic resistant cases claiming thousands of lives and a substantial impact economically. Of these, the CDC has identified carbapenems and extended spectrum cephalosporin resistance in Enterobacteriaceaeas serious public health threats. The aims of our study are: 1) To determine the differential loads of carbapenem-resistant and ESBL-producing Escherichia coli between hospital and urban wastewater; 2) To determine the effect of wastewater treatment on the prevalence of antibiotic resistant E. coli isolates. Methods: Hospital wastewater, as well as influent, pre-chlorinated and post-chlorinated effluents from an urban wastewater treatment facility were filtered and placed on modified mTEC with or without cefotaxime (2 µg/ml) to obtain E. coli isolates. Wastewater samples were obtained during Fall 2018. Antimicrobial susceptibility of isolates was determined using the Kirby-Bauer disk diffusion assay for ceftriaxone, ceftazidime, ceftazidime/clavulanic acid, cefotaxime, carbapenems, and 7 others. Results: Overall, urban wastewater influents contained over one log higher E. coli CFUs than hospital wastewater. After analyzing 126 isolates from all water sources, the average multiple antibiotic resistance (MAR) index was over seven times greater in hospital isolates compared to urban influents. Multi-drug resistance (2 or more antibiotic groups) was highest among hospital isolates > post-chlorinated > influent = pre-chlorinated. All isolates were susceptible to carbapenems, but 8.7% were ESBLs producers. Although E. coli CFUs were reduced 5 logs post-wastewater treatment, MAR index of post-chlorination isolates was double compared to influents. The samples isolated and grown on mTEC with cefotaxime, the highest MAR samples were found in the hospital wastewater averaging resistance to 7 of 12 antibiotics tested. Discussion: Our data highlight the high prevalence of MDR E. coli isolates in hospital wastewater and suggests resilience of these isolates to chlorination.
Comparative Analysis of Antibiotic Resistance Among Escherichia coli Isolates Within Hospital Wastewater and Throughout the Urban Wastewater Process.
Union Wisconsin Room
Background: Annually, the United States combats two million antibiotic resistant cases claiming thousands of lives and a substantial impact economically. Of these, the CDC has identified carbapenems and extended spectrum cephalosporin resistance in Enterobacteriaceaeas serious public health threats. The aims of our study are: 1) To determine the differential loads of carbapenem-resistant and ESBL-producing Escherichia coli between hospital and urban wastewater; 2) To determine the effect of wastewater treatment on the prevalence of antibiotic resistant E. coli isolates. Methods: Hospital wastewater, as well as influent, pre-chlorinated and post-chlorinated effluents from an urban wastewater treatment facility were filtered and placed on modified mTEC with or without cefotaxime (2 µg/ml) to obtain E. coli isolates. Wastewater samples were obtained during Fall 2018. Antimicrobial susceptibility of isolates was determined using the Kirby-Bauer disk diffusion assay for ceftriaxone, ceftazidime, ceftazidime/clavulanic acid, cefotaxime, carbapenems, and 7 others. Results: Overall, urban wastewater influents contained over one log higher E. coli CFUs than hospital wastewater. After analyzing 126 isolates from all water sources, the average multiple antibiotic resistance (MAR) index was over seven times greater in hospital isolates compared to urban influents. Multi-drug resistance (2 or more antibiotic groups) was highest among hospital isolates > post-chlorinated > influent = pre-chlorinated. All isolates were susceptible to carbapenems, but 8.7% were ESBLs producers. Although E. coli CFUs were reduced 5 logs post-wastewater treatment, MAR index of post-chlorination isolates was double compared to influents. The samples isolated and grown on mTEC with cefotaxime, the highest MAR samples were found in the hospital wastewater averaging resistance to 7 of 12 antibiotics tested. Discussion: Our data highlight the high prevalence of MDR E. coli isolates in hospital wastewater and suggests resilience of these isolates to chlorination.
