The occurrence of specific markers of Bacteroides fragilis group, B. dorei and antibiotic-resistance genes in the wastewater treatment plants

Abstract

Wastewater treatment plants (WWTPs) are one of the main transmission sources of pathogenic bacteria and antibiotic-resistance genes in the natural environment. In this study, the presence of specific markers of Bacteroides fragilis group (BFG), B. dorei and genes encoding resistance to beta-lactams (cepA, cfxA), tetracyclines (tet(Q)), macrolides, lincosamides and streptogramins (MLS) mechanism (ermF, linA) was analyzed by standard PCR in the inflows and outflows from three wastewater treatment plants with the activated sludge process. Genetic material was isolated from wastewater samples with the use of two commercial kits for genomic DNA extraction, the Fast DNA SPIN Kit for Soil and the Genomic Micro AX Bacteria Gravity Kit. The quality of the isolated genetic material differed between the tested isolation kits. The Fast DNA SPIN Kit for Soil was more effective in detecting cfxA, ermF and linA genes. However, both extraction kits effectively identified tet(Q), bfr and HF183/BacR287 genes in all wastewater samples. The results of the study indicate that genes specific to BFG and B. dorei, and genes encoding resistance to MLS and tetracyclines are not completely eliminated during the wastewater treatment process.

Development of Antibiotic Resistance in Wastewater Treatment Plants

“…Presence of specific genes encoding resistance to tetracyclines (tetQ [48], tetA [49], and tetO [50]), sulfonamide (sul1 [49] sul2 [50]), erythromycin (mphB [49]), quinolone (qnrD [49] and qnrS [50]), beta-lactams (cepA, cfxA [48], bla CTX-M , and bla TEM [50]), erythromycin (ermB), methicillin (mecA), vancomycin (vanA) [50], and aminoglycoside (aac(3)-II, aacA4, aadA, aadB, aadE, aphA1, aphA2, strA and strB [51]) were analyzed and confirmed by recent studies. The results of these studies prove that WWTPs are the main source of antibiotic resistance transmission.…”