Characterization of Plasmids Carrying CMY-2 from Expanded-Spectrum Cephalosporin-Resistant Salmonella Strains Isolated in the United States between 1996 and 1998

University of Nebraska at Omaha, Omaha, Nebraska, United States
Antimicrobial Agents and Chemotherapy (Impact Factor: 4.45). 06/2002; 46(5):1269-72. DOI: 10.1128/AAC.46.5.1269-1272.2002
Source: PubMed

ABSTRACT Sequencing of DNA from 15 expanded-spectrum cephalosporin (e.g., ceftriaxone)-resistant Salmonella isolates obtained in the United States revealed that resistance to ceftriaxone in all isolates was mediated by cmy-2. Hybridization patterns revealed three plasmid structures containing cmy-2 in these 15 isolates. These data suggest that the spread of cmy-2 among Salmonella strains is occurring through mobilization of the cmy-2 gene into different plasmid backbones and consequent horizontal transfer by conjugation.

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    • "Plasmid-mediated β-lactamases were classified into six genetic clusters and blaCMY was the most prevalent one. The blaCMY has been found on plasmid of sizes variable for 7 to 180 kb [5] [6]. Plasmid-mediated quinolone resistance (PMQR) was first discovered in a clinical isolate of Kelebsiella penemoniae from Birmingham, Albama collected in 1998 by Martinez-Martinez. "
    Advances in Microbiology 01/2014; 04(01):63-68. DOI:10.4236/aim.2014.41010
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    • "An attenuator-like structure – similar to that of inducibly expressed catA genes – was detected upstream of the cmlA gene [123]. During the last decade, a number of genes closely related to or indistinguishable from cmlA – and all assigned to group E-1 – have been identified in a wide variety of Gram-negative bacteria, including E. coli [126], S. Typhimurium [127], Klebsiella pneumoniae [128] [129], and P. aeruginosa [130] [131] [132], but also from an uncultured eubacterium [103] (Table 3). E. coli strains carrying the gene cmlA were reported to exhibit MICs of Cm of P 32 to >256 mg l À1 and MICs of Ff of 6 8 to 64 mg l À1 [133] [134]. "
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    ABSTRACT: Chloramphenicol (Cm) and its fluorinated derivative florfenicol (Ff) represent highly potent inhibitors of bacterial protein biosynthesis. As a consequence of the use of Cm in human and veterinary medicine, bacterial pathogens of various species and genera have developed and/or acquired Cm resistance. Ff is solely used in veterinary medicine and has been introduced into clinical use in the mid-1990s. Of the Cm resistance genes known to date, only a small number also mediates resistance to Ff. In this review, we present an overview of the different mechanisms responsible for resistance to Cm and Ff with particular focus on the two different types of chloramphenicol acetyltransferases (CATs), specific exporters and multidrug transporters. Phylogenetic trees of the different CAT proteins and exporter proteins were constructed on the basis of a multisequence alignment. Moreover, information is provided on the mobile genetic elements carrying Cm or Cm/Ff resistance genes to provide a basis for the understanding of the distribution and the spread of Cm resistance--even in the absence of a selective pressure imposed by the use of Cm or Ff.
    FEMS Microbiology Reviews 11/2004; 28(5):519-42. DOI:10.1016/j.femsre.2004.04.001 · 13.81 Impact Factor
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    • "Although the plasmids obtained from Salmonella strains were not identical (Fig. 1, panel (a), lanes 2–8), restriction analysis suggested that they were similar to one another but different from the E. coli BN10660 plasmid (Fig. 1, panel (a), lane 1). Plasmid profiles were hybridized with specific probes as described previously [4] [19]. These included the bla CMY-2 gene and the orfA 0 –floR–orfA gene cluster, the latter obtained from the cloned floR plasmid pEF03 (Fig. 1). "
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    ABSTRACT: Multidrug resistance plasmids carrying the blaCMY-2 gene have been identified in Salmonella enterica serovars Typhimurium and Newport from the United States. This gene confers decreased susceptibility to ceftriaxone, and is most often found in strains with concomitant resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and tetracycline. The blaCMY-2-carrying plasmids studied here were shown to also carry the florfenicol resistance gene, floR, on a genetic structure previously identified in Escherichia coli plasmids in Europe. These data indicate that the use of different antimicrobial agents, including phenicols, may serve to maintain multidrug resistance plasmids on which extended-spectrum cephalosporin resistance determinants co-exist with other resistance genes in Salmonella.
    FEMS Microbiology Letters 04/2004; 233(2). DOI:10.1111/j.1574-6968.2004.tb09496.x · 2.72 Impact Factor
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