TY - JOUR
T1 - Fate of cefotaxime-resistant Enterobacteriaceae and ESBL-producers over a full-scale wastewater treatment process with UV disinfection
AU - Silva, Isabel
AU - Tacão, Marta
AU - Tavares, Rafael D. S.
AU - Miranda, Rita
AU - Araújo, Susana
AU - Manaia, Célia M.
AU - Henriques, Isabel
N1 - Funding Information:
This work was supported by National Funds from FCT – Fundação para a Ciência e a Tecnologia - through project WaterJPI/0002/2013 “StARE: Stopping Antibiotic Resistance Evolution”. Authors also acknowledge FCT1 financing to Isabel Henriques (FCT Investigator Programme – IF/00492/2013 ), Marta Tacão ( SFRH/114855/2016 ) and Susana Araújo (PhD grant SFRH/BD/52573/2014 ). Furthermore, thanks are due for the financial support to CESAM ( UID/AMB/50017-POCI-01-0145-FEDER-007638 ), to FCT/MCTES through national funds (PIDDAC), and the co-funding by the FEDER , within the PT2020 Partnership Agreement and Compete 2020.
Funding Information:
This work was supported by National Funds from FCT – Fundação para a Ciência e a Tecnologia - through project WaterJPI/0002/2013 “StARE: Stopping Antibiotic Resistance Evolution”. Authors also acknowledge FCT1 financing to Isabel Henriques (FCT Investigator Programme – IF/00492/2013), Marta Tacão (SFRH/114855/2016) and Susana Araújo (PhD grant SFRH/BD/52573/2014). Furthermore, thanks are due for the financial support to CESAM (UID/AMB/50017-POCI-01-0145-FEDER-007638), to FCT/MCTES through national funds (PIDDAC), and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020.
Publisher Copyright:
© 2018
PY - 2018/10/15
Y1 - 2018/10/15
N2 - Disinfection by UV radiation is one of the most promising solutions to reduce the bacterial load and antibiotic resistance in the final effluents of urban wastewater treatment plants (UWTP). Our aim was to evaluate the fate of cefotaxime-resistant Enterobacteriaceae and Extended Spectrum Beta-Lactamase (ESBL) producers in a full-scale system that includes UV-C disinfection. Over treatment, the abundance of cefotaxime-resistant Enterobacteriaceae was reduced, with reductions of 1.9 log units after secondary treatment (STW samples) and 1.8 log following UV disinfection (UTW samples). These reductions, did not reflect the variations in the prevalence of cefotaxime-resistant Enterobacteriaceae, estimated to be of 3% in raw wastewater (RW), 18% in STW and 3% in UTW. A significant increase of cefotaxime-resistant bacterial counts (0.5 log; p < 0.05) was observed after 3 days of storage. In a total of 1799 cefotaxime-resistant Enterobacteriaceae isolates, 15% harboured blaCTX-M (n = 274), 11% blaTEM (n = 194) and 4% blaSHV (n = 72). While the ESBL gene prevalence decreased over treatment, the prevalence of the intI1 gene decreased after ST but slightly increased in UTW samples. The blaCTX-M-carriers were identified as Escherichia coli and Klebsiella pneumoniae, mostly multi-drug resistant (90.5%) and carrying integrase genes (82.8%). The blaCTX-M gene variants (48 blaCTX-M-15, 9 blaCTX-M-32, 8 blaCTX-M-1, 5 blaCTX-M-27, and 2 blaCTX-M-14) were flanked by ISEcp1, ISEcp1/IS26, IS903 and ORF477 in 8 different arrangements. The IncF plasmid replicon type was highly prevalent among blaCTX-M-carrying Escherichia coli (74.5%) while IncR predominated among K. pneumoniae (54.5%). Our results confirmed the potential of UV-C disinfection to remove antibiotic resistant bacteria. Still, resistant Enterobacteriaceae (about 30 cells per m3 of water), presenting traits that might potentiate antibiotic resistance spread, are released in the final effluent. In addition, a significant regrowth was observed after storage. These results suggest that improvements of wastewater disinfection are still required to minimize the risks associated with UWTP discharges.
AB - Disinfection by UV radiation is one of the most promising solutions to reduce the bacterial load and antibiotic resistance in the final effluents of urban wastewater treatment plants (UWTP). Our aim was to evaluate the fate of cefotaxime-resistant Enterobacteriaceae and Extended Spectrum Beta-Lactamase (ESBL) producers in a full-scale system that includes UV-C disinfection. Over treatment, the abundance of cefotaxime-resistant Enterobacteriaceae was reduced, with reductions of 1.9 log units after secondary treatment (STW samples) and 1.8 log following UV disinfection (UTW samples). These reductions, did not reflect the variations in the prevalence of cefotaxime-resistant Enterobacteriaceae, estimated to be of 3% in raw wastewater (RW), 18% in STW and 3% in UTW. A significant increase of cefotaxime-resistant bacterial counts (0.5 log; p < 0.05) was observed after 3 days of storage. In a total of 1799 cefotaxime-resistant Enterobacteriaceae isolates, 15% harboured blaCTX-M (n = 274), 11% blaTEM (n = 194) and 4% blaSHV (n = 72). While the ESBL gene prevalence decreased over treatment, the prevalence of the intI1 gene decreased after ST but slightly increased in UTW samples. The blaCTX-M-carriers were identified as Escherichia coli and Klebsiella pneumoniae, mostly multi-drug resistant (90.5%) and carrying integrase genes (82.8%). The blaCTX-M gene variants (48 blaCTX-M-15, 9 blaCTX-M-32, 8 blaCTX-M-1, 5 blaCTX-M-27, and 2 blaCTX-M-14) were flanked by ISEcp1, ISEcp1/IS26, IS903 and ORF477 in 8 different arrangements. The IncF plasmid replicon type was highly prevalent among blaCTX-M-carrying Escherichia coli (74.5%) while IncR predominated among K. pneumoniae (54.5%). Our results confirmed the potential of UV-C disinfection to remove antibiotic resistant bacteria. Still, resistant Enterobacteriaceae (about 30 cells per m3 of water), presenting traits that might potentiate antibiotic resistance spread, are released in the final effluent. In addition, a significant regrowth was observed after storage. These results suggest that improvements of wastewater disinfection are still required to minimize the risks associated with UWTP discharges.
KW - Bla
KW - Escherichia coli
KW - Extended spectrum beta-lactamases (ESBLs)
KW - Klebsiella pneumoniae
KW - Urban wastewater treatment plants
KW - UV-C disinfection
UR - http://www.scopus.com/inward/record.url?scp=85047305678&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2018.05.229
DO - 10.1016/j.scitotenv.2018.05.229
M3 - Article
C2 - 29929272
AN - SCOPUS:85047305678
SN - 0048-9697
VL - 639
SP - 1028
EP - 1037
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -
