Occurrence of extended-spectrum β-lactamase (ESBL)/AmpC producing bacteria in wastewater treatment plant effluent

Abstract

Extended-spectrum β-lactamase (ESBL)/AmpC producing bacteria are one of the critical priority resistant bacteria that contributes to treatment failure and increased death rates. In this work we aimed to study the role of wastewater treatment plants (WWTPs) as reservoirs of ESBL/AmpC producing faecal coliforms. The effluent samples were collected from two WWTPs and faecal coliforms were isolated from all samples using the membrane filtration method. Bacterial isolates were subjected to antimicrobial susceptibility testing toward cefotaxime and ceftazidime. The isolates that showed a resistance phenotype to these antibiotics were considered as putative ESBL/AmpC producing bacteria. These bacteria were subjected to the AmpC test using a protocol with phenylboronic acid. The AmpC negative strains in the AmpC test served as samples for multiplex PCR containing primers specific for blaTEM, blaSHV and blaCTX-M. In total, 498 faecal coliforms were isolated from WWTP effluent samples. For the antibiotic susceptibility testing 99 isolates were considered as ESBL/AmpC producing bacteria. Among them, 26 isolates were found to be positive in the AmpC test. The PCR results revealed that 49 isolates carried blaTEM, 6 bla SHV12, 1 blaCTX-M1 and 5 blaCTX-M15. The ESBL/AmpC producing faecal coliforms in WWTP effluent are discharged to the receiving water environment. These data need to be considered when analysing the risk of WWTP effluent to the environment and to human health, as many of the bacteria identified are not analysed in assessment of risk of pollution from WWTPs globally.

Antibiotic resistance gene-free probiont administration to tilapia for growth performance and Streptococcus agalactiae resistance

“…Moreover, the relationship between fish and their environment has been investigated in species [43,44] such as channel catfish, Ictalurus punctatus [45], Alburnus alburnus [46], sea bass [47], yellow tail fish [48], common carp and koi carp [49], shrimp [50], Ebro barbel (Luciobarbus graellsii), brown trout (Salmo trutta) [51], and tilapia (Oreochomis niloticus) [52,53]. Other sectors, such as animal husbandry and household waste, influence resistance genes in aquaculture [54][55][56][57][58][59][60][61][62][63][64][65][66]. The interconnected roles of different sectors can impact the quality of the environment and contribute to the distribution of microorganisms, including the spread of antibiotic-resistant bacteria.…”