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: 4.48). 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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Available from: Fabio Tosini, Sep 26, 2015
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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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    • "The objective of the current study was to examine the association between the recently emerged genotype MDR ST213 and blaCMY-2 plasmids. ST213 isolates were analyzed by plasmid profiling, PCR replicon typing [19], plasmid PstI restriction profiles [12,20], Southern hybridization, plasmid PCR screening and sequencing of regions scattered throughout the IncA/C plasmids [8], and by their conjugation abilities. We found two divergent types of IncA/C plasmids: one composed of plasmids possessing or lacking the blaCMY-2 region and the other lacking blaCMY-2. "
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    ABSTRACT: Salmonella Typhimurium ST213 was first detected in the Mexican Typhimurium population in 2001. It is associated with a multi-drug resistance phenotype and a plasmid-borne blaCMY-2 gene conferring resistance to extended-spectrum cephalosporins. The objective of the current study was to examine the association between the ST213 genotype and blaCMY-2 plasmids. The blaCMY-2 gene was carried by an IncA/C plasmid. ST213 strains lacking the blaCMY-2 gene carried a different IncA/C plasmid. PCR analysis of seven DNA regions distributed throughout the plasmids showed that these IncA/C plasmids were related, but the presence and absence of DNA stretches produced two divergent types I and II. A class 1 integron (dfrA12, orfF and aadA2) was detected in most of the type I plasmids. Type I contained all the plasmids carrying the blaCMY-2 gene and a subset of plasmids lacking blaCMY-2. Type II included all of the remaining blaCMY-2-negative plasmids. A sequence comparison of the seven DNA regions showed that both types were closely related to IncA/C plasmids found in Escherichia, Salmonella, Yersinia, Photobacterium, Vibrio and Aeromonas. Analysis of our Typhimurium strains showed that the region containing the blaCMY-2 gene is inserted between traA and traC as a single copy, like in the E. coli plasmid pAR060302. The floR allele was identical to that of Newport pSN254, suggesting a mosaic pattern of ancestry with plasmids from other Salmonella serovars and E. coli. Only one of the tested strains was able to conjugate the IncA/C plasmid at very low frequencies (10-7 to 10-9). The lack of conjugation ability of our IncA/C plasmids agrees with the clonal dissemination trend suggested by the chromosomal backgrounds and plasmid pattern associations. The ecological success of the newly emerging Typhimurium ST213 genotype in Mexico may be related to the carriage of IncA/C plasmids. We conclude that types I and II of IncA/C plasmids originated from a common ancestor and that the insertion and deletion of DNA stretches have shaped their evolutionary histories.
    BMC Microbiology 01/2011; 11(1):9. DOI:10.1186/1471-2180-11-9 · 2.73 Impact Factor
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    • "B) The presence of the Typhimurium virulence plasmid (pSTV) [GenBank:AE006471] was determined by PCR amplification of three genes involved in virulence spvC, rck and traT [19,28], and by Southern hybridisation on plasmid profiles using spvC as probe. C) The presence of the plasmid-borne cmy-2 gene, conferring resistance to extended spectrum cephalosporins [GenBank:NC_011079] [30,31], was determined by PCR and by Southern hybridisation on plasmid profiles. The chloramphenicol determinant floR was also assessed, since it has been reported that both resistances are often encoded by the same plasmid [48]. "
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    ABSTRACT: Bacterial genomes are mosaic structures composed of genes present in every strain of the same species (core genome), and genes present in some but not all strains of a species (accessory genome). The aim of this study was to compare the genetic diversity of core and accessory genes of a Salmonella enterica subspecies enterica serovar Typhimurium (Typhimurium) population isolated from food-animal and human sources in four regions of Mexico. Multilocus sequence typing (MLST) and macrorestriction fingerprints by pulsed-field gel electrophoresis (PFGE) were used to address the core genetic variation, and genes involved in pathogenesis and antibiotic resistance were selected to evaluate the accessory genome. We found a low genetic diversity for both housekeeping and accessory genes. Sequence type 19 (ST19) was supported as the founder genotype of STs 213, 302 and 429. We found a temporal pattern in which the derived ST213 is replacing the founder ST19 in the four geographic regions analyzed and a geographic trend in the number of resistance determinants. The distribution of the accessory genes was not random among chromosomal genotypes. We detected strong associations among the different accessory genes and the multilocus chromosomal genotypes (STs). First, the Salmonella virulence plasmid (pSTV) was found mostly in ST19 isolates. Second, the plasmid-borne betalactamase cmy-2 was found only in ST213 isolates. Third, the most abundant integron, IP-1 (dfrA12, orfF and aadA2), was found only in ST213 isolates. Fourth, the Salmonella genomic island (SGI1) was found mainly in a subgroup of ST19 isolates carrying pSTV. The mapping of accessory genes and multilocus genotypes on the dendrogram derived from macrorestiction fingerprints allowed the establishment of genetic subgroups within the population. Despite the low levels of genetic diversity of core and accessory genes, the non-random distribution of the accessory genes across chromosomal backgrounds allowed us to discover genetic subgroups within the population. This study provides information about the importance of the accessory genome in generating genetic variability within a bacterial population.
    BMC Microbiology 08/2009; 9(1):131. DOI:10.1186/1471-2180-9-131 · 2.73 Impact Factor
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