Antibiotic resistance in wastewater: Occurrence and fate ofEnterobacteriaceaeproducers of Class A and Class C β-lactamases

Abstract

Antibiotics have been intensively used over the last decades in human and animal therapy and livestock, resulting in serious environmental and public health problems, namely due to the antibiotic residues concentration in wastewaters and to the development of antibiotic-resistant bacteria. This study aimed to access the contribution of some anthropological activities, namely urban household, hospital and a wastewater treatment plant, to the spread of antibiotic resistances in the treated wastewater released into the Mondego River, Coimbra, Portugal. Six sampling sites were selected in the wastewater network and in the river. The ampicillin-resistant Enterobacteriaceae of the water samples were enumerated, isolated and phenotypically characterized in relation to their resistance profile to 13 antibiotics. Some isolates were identified into species level and investigated for the presence of class A and class C -lactamases. Results revealed high frequency of resistance to the -lactam group, cefoxitin (53.5%), amoxicillin/clavulanic acid combination (43.5%), cefotaxime (22.7%), aztreonam (21.3) cefpirome (19.2%), ceftazidime (16.2%) and to the non--lactam group, trimethoprim/sulfamethoxazol (21.1%), tetracycline (18.2%), followed by ciprofloxacin (14.1%). The hospital effluent showed the higher rates of resistance to all antibiotic, except two (chloramphenicol and gentamicin). Similarly, higher resistance rates were detected in the wastewater treatment plant (WWTP) effluent compared with the untreated affluent. Regarding the multidrug resistance, the highest incidence was recorded in the hospital sewage and the lowest in the urban waste. The majority of the isolates altogether are potentially extended-spectrum -lactamases positive (ESBL(+)) (51.9%), followed by AmpC(+) (44.4%) and ESBL(+)/AmpC(+) (35.2%). The most prevalent genes among the potential ESBL producers were blaOXA (33.3%), blaTEM (24.1%) and blaCTX-M (5.6%) and among the AmpC producers were blaEBC (38.9%), blaFOX (1.9%) and blaCIT (1.9%). In conclusion, the hospital and the WWTP activities revealed to have the highest contribution to the spread of multidrug resistant bacteria in the study area. Such data is important for future management of the environmental and public health risk of these contaminants. This is the first embracing study in the water network of Coimbra region on the dissemination of antibiotic resistance determinants. Moreover, it is also the first report with the simultaneous detection of multiresistant bacteria producers of AmpC and ESBLs -lactamases in aquatic systems in Portugal.

Diversity of β-lactam resistance genes in gram-negative rods isolated from a municipal wastewater treatment plant

“…However, little is known about the dissemination of this β-lactamase in an aqueous environment. Amador et al (Amador et al 2015) found bla EBC gene, including bla ACT , the most prevalent gene of the AmpC βlactamase type (38.9%). There was also a report on bla gene that was found in Enterobacter asburiae isolated from a water distribution network (Manageiro et al 2014).…”

“…The number continues to grow. B-lactamase resistance genes belonging to the AmpC, ESBL, KPC, and NDM groups have been found in bacteria identified in wastewater (Zhang et al 2009;Picão et al 2013;Khan and Parvez 2014;Amador et al 2015;Varela et al 2016;Piotrowska et al 2017). However, our understanding of the diversity of types and variants is still limited.…”

Molecular characterization of quinolone resistance mechanisms and extended-spectrum β-lactamase production in Escherichia coli isolated from dogs

“…Positive control strains were used in each set of PCRs, as described in previous studies [24,25]. For DNA Sanger sequencing (Macrogen, Amsterdam, The Netherlands), PCR products were purified using the GRS PCR & Gel Band Purification Kit (Grisp, Porto, Portugal).…”

Anforderungen der Hygiene an abwasserführende Systeme in medizinischen Einrichtungen

“…In den letzten Jahren haben sich wissenschaftliche Publikationen zum Vorkommen von antibiotikaresistenten Erregern einschließlich von Reserve-Antibiotika wie Carbapenemen und Colistin in Abwässern gehäuft [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”