Antimicrobial resistance genes and bacterial diversity in sediments of Guandu River, Brazil

Abstract

Rivers provide essential water resources for humans. However, appear to be reservoirs of antimicrobial-resistant genes and dispersal routes of resistant pathogens because human activities promptly influence them. Sediments are the most propitious substrates for bacteria survival and can act as an antimicrobial reservoir. Three sediment samples were collected upstream of the water catchment point of the Guandu Water Treatment Plant (ETA Guandu) to evaluate microbial diversity and antimicrobial resistance genes to sulfonamide (sul1, sul2), tetracycline (tetA, tetB) and beta-lactam (blaCTX-M, blaoxa24 and blaoxa58) by PCR. The most abundant phylum in all samples was Proteobacteria, which was also the most dominant in sediments presenting a pattern already reported in the literature for diversity in tropical and temperate climate rivers. Sulfonamide resistance genes were detected in all samples. The blaCTX-M gene was detected only in one sample, and tetA, tetB, blaoxa24 and blaoxa58 genes were not found in any sample. The presence of antimicrobial resistance genes sul1, sul2, and blaCTX-M indicate that sediments can act as a reservoir of resistance. These findings will provide new data about the bacterial community and antimicrobial resistance genes in Brazilians river sediments.