Integron gene cassettes in Acinetobacter spp. strains from South China

The epidemiology of emerging antibiotic resistance genes in Asia is inadequately defined and studies within the major pools of transmissible genes such as integron gene cassettes are important. One hundred and twenty-two non-repetitive Acinetobacter spp. isolates were obtained from inpatients of a major hospital in South China. Fifty-three of these isolates contained class 1 integrons, and there is evidence of horizontal gene transfer between unrelated clones. The common pool of gene cassettes was dominated by four cassette arrays: arr3-aacA4 (24 isolates of several unrelated strains); aacC1-orfP-orfQ-aadA1a (11 isolates, probably all the same strain); aacA4-catB8-aadA1 (2 isolates); and dfrVII (1 isolate). We developed a simple restriction fragment length polymorphism (RFLP)-based identification of these and other cassettes reported in China, using readily available enzymes, to facilitate further studies of this type.