Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock
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The Ohio State University / OhioLINK
2012
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1343231339 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu13432313392021-08-03T06:06:02Z Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock Mollenkopf, Dixie Francis Epidemiology CTX-M livestock dairy resistance cephalosporin blaCTX-M β-lactamases confer resistance to critically important cephalosporin drugs. Recovered from both hospital and community-acquired infections, blaCTX-M was first reported in US livestock in 2010. It has been hypothesized that veterinary use of cephalosporins in livestock populations may lead to the dissemination of β-lactamase encoding genes. Therefore, our objectives were to estimate the frequency and distribution of coliform bacteria harboring blaCTX-M in the fecal flora of Ohio dairy cattle populations. In addition, we characterized the CTX-M alleles carried by the isolates, their plasmidic contexts, and the genetic diversity of the bacterial isolates themselves. We also evaluated the association between ceftiofur use and the likelihood of recovering cephalosporinase-producing bacteria. Thirty fresh fecal samples and owner-reported ceftiofur use data were collected from each of 25 Ohio dairy farms. Fecal samples (n=747) yielded 70 blaCTX-M positive E. coli from 5/25 herds, 715 blaCMY-2 E. coli from 25/25 herds and 274 Salmonella spp. from 20/25 herds. The within-herd prevalence of blaCTX-M positive herds ranged from 3.3 to 100 % of samples. Multiple PFGE patterns, plasmid replicon types and CTX-M genes were detected. Plasmids encoding CTX-M-1, -15, and -14 alleles were clonal by RFLP within herds and specific plasmid incompatibility group markers were consistently associated with each blaCTX-M allele. PFGE of total bacterial DNA showed similar within-herd clustering with the exception of one herd, which revealed at least 6 different PFGE signatures. We were unable to detect an association between owner-reported ceftiofur use and the probability of recovering E. coli carrying blaCTX-M or blaCMY-2. 2012-08-16 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1343231339 http://rave.ohiolink.edu/etdc/view?acc_num=osu1343231339 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Epidemiology CTX-M livestock dairy resistance cephalosporin |
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Epidemiology CTX-M livestock dairy resistance cephalosporin Mollenkopf, Dixie Francis Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock |
| author |
Mollenkopf, Dixie Francis |
| author_facet |
Mollenkopf, Dixie Francis |
| author_sort |
Mollenkopf, Dixie Francis |
| title |
Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock |
| title_short |
Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock |
| title_full |
Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock |
| title_fullStr |
Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock |
| title_full_unstemmed |
Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock |
| title_sort |
epidemiology of ctx-m cephalosporinase-bearing escherichia coli and salmonella spp. isolated from us livestock |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2012 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1343231339 |
| work_keys_str_mv |
AT mollenkopfdixiefrancis epidemiologyofctxmcephalosporinasebearingescherichiacoliandsalmonellasppisolatedfromuslivestock |
| _version_ |
1719430893196541952 |