We screened nine PMQR genes in
We screened nine PMQR Tivantinib in all 24 CIPr isolates to confirm the distribution of PMQR genes (Table 2). None of nine PMQR genes were identified in the three CIPr isolates from the control samples. The QnrA, qnrB, qnrC, and qnrS genes were absent in the 21 CIPr isolates from manured soil and are thus not listed in Table 2. Among the 21 CIPr isolates from manured soil, 18 isolates were positive for the other five PMQR genes, including 12 for aac(6′)-Ib-cr, four for qepA, five for qnrD, four for oqxA, and four for oqxB, indicating that the five PMQR genes might be derived from swine manure. Most of the five PMQR genes have been detected in Escherichia coli strains isolated from swine manure. For instance, oqxAB, conferring resistance to olaquindox, which is used as a veterinary growth promoter, was originally identified in an E. coli isolate from swine manure ( Hansen et al., 2004). A study from China showed the high prevalence of qepA among E. coli isolates from swine feces ( Liu et al., 2008). Nevertheless, to our knowledge, this study is the first report on the presence of PMQR genes in FQ-resistant isolates from the soil environment.