Co-occurrence of mcr-1, mcr-3, mcr-7 and clinically relevant antimicrobial resistance genes in environmental and fecal samples

Multidrug-resistant bacteria harboring different antimicrobial resistance genes (ARGs) have been detected worldwide. The association of plasmid-mediated colistin resistance genes ( mcr-like ) and other ARGs in bacteria isolated from animals is a huge concern worldwide. Therefore, this study aimed to investigate the presence of mcr-like genes and clinically relevant ARGs as well as plasmids in samples from a zoo. Fecal and environmental (soil and water) samples were collected from a zoo and the DNA of cultivable aerobic bacteria was extracted. ARGs were screened by PCR and the plasmids were detected using the PCR-based replicon typing method. A total of 74 amplicons from 27 ARGs [ mcr-1 , mcr-3 , mcr-7.1 , bla CTX-M-Gp1 , bla CTX-M-Gp2 , bla CTX-M-Gp9 , bla VEB , bla PER , bla CMY , tetA, tetB, tetC, aadA, aac(6′)-Ib, aph(3′)-Ia, ant(2′')-Ia , qnrA , qnrB, qnrS, oqxA, oqxB , sul1, sul2, sul3, cmlA, mefAE , ermB ] and 21 amplicons from eight plasmid families (IncY, ColE- like , IncF repB , IncFIA, IncFIB, IncHI1, IncFIC, IncP) were detected. These findings reinforce that the zoo acts as a reservoir of clinically relevant ARGs, including mcr-like , and call attention to the monitoring studies in the zoo. Therefore, to the best of our knowledge, this is the first report of the world of mcr-1 , mcr-3 and mcr-7.1 in environmental samples from the zoo.