complex integrons containing qnrb4-ampc (bla(dha-1)) in plasmids of multidrug-resistant citrobacter freundii from wastewater. | microbial populations in wastewater treatment plants (wwtps) are increasingly being recognized as environmental reservoirs of antibiotic resistance genes. pcr amplicons for plasmid-mediated quinolone resistance determinants qnra, qnrb, and qnrs were recorded in samples from a wwtp in vancouver, british columbia. six strains of ciprofloxacin-resistant citrobacter freundii were isolated and found to carry mutations in gyra and parc, as well as multiple plasmid-borne resistance genes, collectively ... | 2012 | 23461518 |