Multidrug resistance mechanism of pathogenic bacteria by mobile genetic elements

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The purpose of this study is to understand the roles of mobile genetic elements in spread of antibiotic resistance genes among pathogenic bacteria.(1) Genetic characterization of multidrug resistance in Shigella spp. from JapanWe characterized the genetic basis of antimicrobial resistance of many Shigella spp. isolated from humans during 2000-2004 in Hiroshima prefecture, Japan.(2) Proteus mirabilis clinical isolate harboring a new variant of Salmonella genomic island 1 containing the multiple antibiotic resistance regionWe identified a new variant SGI1 containing the multiple resistance genomic region in a multidrug-resistant strain of P. mirabilis. This is the first report for SGI1 in a genus other than Salmonella.(3) Zoo animals as a reservoir of Gram-negative bacteria harboring integrons and antimicrobial resistance genes A total of 232 isolates of gram-negative bacteria were recovered from mammals, reptiles and birds housed at Zoological Park, Hiroshima prefecture, Japan. 49 isola … More tes (21.1%) showed multidrug resistance phenotypes and harbored at least one antimicrobial resistance gene. PCR and DNA sequencing identified class I and class 2 integrons and many β-lactamase-encoding genes, in addition to a novel ampC β-lactamase gene, bla_<CMY-26>. Furthermore, the plasmid-mediated quinolone resistance genes, qnr and aac(6')-Ib-cr, were also identified.(4) Emergence of cefepime- and cefpirome-resistant Citrobacter freundii clinical isolate harbouring a novel chromosomally-encoded AmpC β-lactamase, CMY-37Citrobacter freundii strain 4306 was isolated from a urine specimen of a patient in March 2006 in Palestine. This strain showed a unique multidrug resistance phenotype, as it was resistant to both 7-α-methoxy- and oxyimino-cephalosporins, including cefepime, cefpirome and monobactams, in addition to quinolones, streptomycin and trimethoprim-sulfamethoxazole. Molecular characterization showed that the resistance to 7-α-methoxy- and oxyimino-cephalosporins was due to a novel AmpC β-lactamase, designated CMY-37. Phylogenetic analysis suggested that CMY-37 is the origin of many plasmid-mediated AmpC β-lactamases. Less