Novel IS CR1 -linked resistance genes found in multidrug-resistant Gram-negative bacteria in southern China

Abstract Non-duplicate multidrug-resistant (MDR) Gram-negative bacteria ( n = 1329) isolated from southern China between January 2008 and December 2009 were investigated for the presence of IS CR1 as well as characterisation of IS CR1 -linked resistance genes. Of 433 IS CR1 -positive strains, 151 appeared to carry IS CR1 -linked resistance genes. Seven different IS CR1 -linked resistance gene arrays were identified by restriction fragment length polymorphism (RFLP) and DNA sequencing analysis. Many of these arrays are reported in some species for the first time. A total of 12 genes, including a novel ABC transporter (GenBank accession no. GU944725 ), qnrA1 , qnrB2 , qnrB6 , blaDHA-1 , ampR , blaCTX-M-9 , blaPER-1 , insB , sapA -like peptide transport periplasmic protein, putative glutathione S-transferase and short-chain dehydrogenase/reductase, were detected. This study was the first to employ PCR-RFLP using Hin fI and Rsa I to analyse IS CR1 -linked genes. IS CR1 was widely disseminated among MDR Gram-negative bacteria and was in close association with quinolone resistance and β-lactamase genes (class A and class C) in southern China.