title: Occurrences and Characterization of Antibiotic-Resistant Bacteria and Genetic Determinants of Hospital Wastewater in a Tropical Country.
abstract: Wastewater discharged from clinical isolation and general wards at two hospitals in Singapore was examined to determine the emerging trends of antibiotic resistance (AR). We quantified the concentrations of 12 antibiotic compounds by analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS), antibiotic-resistant bacteria (ARB), the class 1 integrase gene (intI1), and 16 antibiotic resistance genes (ARGs) that confer resistance to 10 different clinically relevant antibiotics. A subset of 119 antibiotic-resistant isolates were phylogenetically classified and tested for the presence of ARGs encoding resistance to β-lactam antibiotics (blaNDM, blaKPC, blaSHV, blaCTX-M), amikacin [aac(6')-Ib], co-trimoxazole (sul1, sul2, dfrA), ciprofloxacin (qnrA, qnrB), and the intI1 gene. Among these resistant isolates, 80.7% were detected with intI1 and 66.4% were found to carry at least 1 of the tested ARGs. Among 3 sampled locations, the clinical isolation ward had the highest concentrations of ARB and the highest levels of ARGs linked to resistance to β-lactam (blaKPC), co-trimoxazole (sul1, sul2, dfrA), amikacin [aac(6')-Ib], ciprofloxacin (qnrA), and intI1 We found strong positive correlations (P < 0.05) between concentrations of bacteria resistant to meropenem, ceftazidime, amikacin, co-trimoxazole, and ciprofloxacin and abundances of blaKPC, aac(6')-Ib, sul1, sul2, dfrA, qnrA, and intI1 genes.
authors.affiliation: NUS Environmental Research Institute (NERI), National University of Singapore, Singapore.
authors.forename: Thai-Hoang
authors.initials: TH
authors.lastname: Le
authors.affiliation: NUS Environmental Research Institute (NERI), National University of Singapore, Singapore.
authors.forename: Charmaine
authors.initials: C
authors.lastname: Ng
authors.affiliation: NUS Environmental Research Institute (NERI), National University of Singapore, Singapore.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Chen
authors.affiliation: NUS Environmental Research Institute (NERI), National University of Singapore, Singapore.
authors.forename: Xin Zhu
authors.initials: XZ
authors.lastname: Yi
authors.affiliation: Department of Pathology, Singapore General Hospital, Singapore.
authors.forename: Tse Hsien
authors.initials: TH
authors.lastname: Koh
authors.affiliation: Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore.
authors.forename: Timothy Mark Sebastian
authors.initials: TM
authors.lastname: Barkham
authors.affiliation: School of Civil Engineering and Division of Environmental and Ecological Engineering, Purdue University, West Lafayette, Indiana, USA.
authors.forename: Zhi
authors.identifier: 0000-0003-1252-2626
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: NUS Environmental Research Institute (NERI), National University of Singapore, Singapore ceeginyh@nus.edu.sg.|Department of Civil & Environmental Engineering, National University of Singapore, Singapore.
authors.forename: Karina Yew-Hoong
authors.initials: KY
authors.lastname: Gin
mesh_terms: D000583:Amikacin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D002853:Chromatography, Liquid; D002939:Ciprofloxacin / Q000494:pharmacology; D004352:Drug Resistance, Microbial / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000302:isolation & purification; D006761:Hospitals; D006801:Humans; D019426:Integrases / Q000235:genetics / Q000302:isolation & purification; D012846:Singapore; D053719:Tandem Mass Spectrometry; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D062065:Wastewater / Q000382:microbiology*; D001618:beta-Lactamases / Q000235:genetics / Q000302:isolation & purification; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000583:Amikacin; D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; D029968:Escherichia coli Proteins; D019426:Integrases; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D062065:Wastewater; D001618:beta-Lactamases; D047090:beta-Lactams; C091882:Sul1 protein, E coli; C115006:integron integrase IntI1; C434283:beta-lactamase KPC-1; C054882:beta-lactamase PIT-2; C000602253:beta-lactamase CTX-M, E coli; C552864:beta-lactamase NDM-1