Community Raw Sewage Effluent as a Reservoir of Resistance Genetic Determinants in Buenos Aires, Argentina.

GHIGLIONE BÁRBARA; BRUNETTI FLORENCIA; FIGUEROA ESPINOSA ROQUE A; BISPO DA SILVA SANTIAGO; PEPE RAZZOLINI M T; DI CONZA JOSÉ; GUTKIND GABRIEL; POWER PABLO; DROPA MILENA

San Francisco

Congreso; ASM MICROBE 2019; 2019

ASM

Background: The presence of antimicrobial resistant microorganisms in the environment is an emerging concern with serious implications for public health. Wastewater treatment plants (WWTPs) in most countries do not focus on reducing antimicrobial resistance determinants, which spread through different environmental sources. In this study, we evaluated the potential spread of waterborne resistance genes and the diversity of β-lactamase producers in a raw sewage effluent from Buenos Aires, Argentina.Methods: A 1000-mL raw sewage sample was collected from a WWTP, and filtered through 0.45µm membranes, DNA extracted and PCR was used for screening plasmid incompatibility (Inc) groups; class 1, 2 and 3 integrases (intI); ISCR1, IS26, IS10 and ISEcp1 transposases; CTX-M, MBLs, PER-2, GES, CMY, KPC and OXA-48 β-lactamase-encoding genes (bla); MCR-1, MCR-2 and MCR-3 phosphoethanolamine-transferase genes. Another membrane was cultivated in McConkey agar and different colonies were isolated. Antibiotic susceptibility testing was performed by disk diffusion (CLSI) and bacterial identification by MALDI-TOF/MS. Suspected β-lactamase producers were assessed by PCR.Results: Inc F group plasmids were detected as well as intI1, intI3 integrases, and ISCR1, IS26, IS10 and ISEcp1 transposases. Different bla genes detected in whole DNA included blaCTX-M, blaOXA-48, blaVIM, blaNDM, blaPER-2, blaGES, blaCMY and blaKPC; mcr-1 and mcr-3 were also detected. KPC-2 producing isolates included K. pneumoniae, K. variicola and E. cloacae Complex. Two E. coli isolates harbored blaCTX-M-2, and 1 K. pneumoniae isolate both blaCTX-M-15 and blaKPC-2; blaIMP was present in K. oxytoca and P. aeruginosa, and blaVIM in P. aeruginosa.Conclusions: The occurrence of genes encoding for resistance to last-choice antimicrobials, as well as mobile genetic elements, in potentially relevant MDR pathogens in a raw sewage sample may contribute to the spread of bacterial resistance. Our results highlight the need to focus on the One Health concept, generating the need to establish effective policies to reduce this growing public health problem.