Concurrent transfer and recombination between plasmids encoding for heat-stable enterotoxin and drug resistance in porcine enterotoxigenicEscherichia coli

Franklin, A.; Möllby, R.

doi:10.1007/bf02123798

Cited by 15 publications

(4 citation statements)

References 27 publications

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“…Conjugation experiments were carried out essentially as described previously (9), except that the strains were grown in LB medium, overnight cultures of donor and recipient strains were diluted 100-fold and incubated for 2 h with aeration at 37°C, and each mating mixture consisted of 0.05 ml of the donor, 0.45 ml of the recipient culture, and 0.5 ml of fresh LB medium. When appropriate, the mating mixture was supplemented with cAMP (10 mM).…”

Section: Methodsmentioning

confidence: 99%

The Cyclic AMP-Cyclic AMP Receptor Protein Complex Regulates Activity of the traJ Promoter of the Escherichia coli Conjugative Plasmid pRK100

et al. 2003

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Section: Methodsmentioning

confidence: 99%

The Cyclic AMP-Cyclic AMP Receptor Protein Complex Regulates Activity of the traJ Promoter of the Escherichia coli Conjugative Plasmid pRK100

et al. 2003

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“…Physical linkages between antimicrobial resistance genes and specific virulence genes in pathogens may be another explanation (32). Such linkages of genes on large transferable plasmids have been described sporadically in the past for enterotoxigenic E. coli (ETEC) isolates from swine and calves (19,23,25,36) and for avian E. coli isolates (28). Nothing is known about the frequency of these associations among field isolates.…”

mentioning

confidence: 99%

Antimicrobial Resistance and Virulence Genes of Escherichia coli Isolates from Swine in Ontario

Boerlin

Travis

Gyles

et al. 2005

Appl Environ Microbiol

296

191

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A total of 318 Escherichia coli isolates obtained from diarrheic and healthy pigs in Ontario from 2001 to 2003were examined for their susceptibility to 19 antimicrobial agents. They were tested by PCR for the presence of resistance genes for tetracycline, streptomycin, sulfonamides, and apramycin and of 12 common virulence genes of porcine E. coli. Antimicrobial resistance frequency among E. coli isolates from swine in Ontario was moderate in comparison with other countries and was higher in isolates from pigs with diarrhea than in isolates from healthy finisher pigs. Resistance profiles suggest that cephamycinases may be produced by >8% of enterotoxigenic E. coli (ETEC). Resistance to quinolones was detected only in enterotoxigenic E. coli (<3%). The presence of sul3 was demonstrated for the first time in Canada in porcine E. coli isolates. Associations were observed among tetA, sul1, aadA, and aac(3)IV and among tetB, sul2, and strA/strB, with a strong negative association between tetA and tetB. The paa and sepA genes were detected in 92% of porcine ETEC, and strong statistical associations due to colocation on a large plasmid were observed between tetA, estA, paa, and sepA. Due at least in part to gene linkages, the distribution of resistance genes was very different between ETEC isolates and other porcine E. coli isolates. This demonstrates that antimicrobial resistance epidemiology differs significantly between pathogenic and commensal E. coli isolates. These results may have important implications with regards to the spread and persistence of resistance and virulence genes in bacterial populations and to the prudent use of antimicrobial agents.

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“…Many virulence genes have been found stably inserted within the chromosome in pathogenic E. coli clones (14,26,31). However, virulence genes can also be associated with elements that promote plasticity within the genome or exchange between bacteria, including plasmids, phages, integrons, and transposons (21,28,43,50). The effect of virulence genes on fitness and survival in environmental matrices including manure, soil, and water is generally unknown.…”

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confidence: 99%

Loss of Virulence Genes in Escherichia coli Populations during Manure Storage on a Commercial Swine Farm

Duriez

Zhang

Lü

et al. 2008

Appl Environ Microbiol

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Confined livestock production farms typically store their wastes prior to land application. Here, we employed three complementary approaches to evaluate changes in the population structure and stability of virulence genes in Escherichia coli during manure storage on a commercial farm that housed healthy swine. Isolates were genotyped by repetitive extragenic palindromic PCR using the BOXA1R primer and evaluated for the presence of selected virulence genes by PCR. Isolates obtained from the manure holding tank (n ‫؍‬ 392) carried estB, fedA, stx 2e , astA, paa, aida-I, and sepA at lower frequencies than isolates obtained from fresh feces (n ‫؍‬ 412). Fresh fecal material from the barn was added into diffusion chambers and immersed in the manure holding tank for 7 weeks. The fecal E. coli population was initially dominated by a single genotype, all isolates of which carried fedA and aida-I. After 7 weeks, a genotype that did not carry any virulence genes dominated the surviving population. In a second experiment, 48 fecal isolates of E. coli that varied in their genotypes and virulence gene complement were incubated in diffusion chambers in the manure holding tank for 3 weeks. Over 95% of the inoculum population carried at least one virulence gene, whereas after 3 weeks 90% of the recovered isolates carried no virulence genes. Taken together, these results indicate that during commercial manure storage, there was a significant reduction in the carriage of these virulence genes by E. coli. We propose that loss of virulence genes from enteric pathogens in the farm and in natural environments may, if generalized, contribute to the attenuation of a public health risk from contamination with agricultural wastes.

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Concurrent transfer and recombination between plasmids encoding for heat-stable enterotoxin and drug resistance in porcine enterotoxigenicEscherichia coli

Cited by 15 publications

References 27 publications

The Cyclic AMP-Cyclic AMP Receptor Protein Complex Regulates Activity of the traJ Promoter of the Escherichia coli Conjugative Plasmid pRK100

The Cyclic AMP-Cyclic AMP Receptor Protein Complex Regulates Activity of the traJ Promoter of the Escherichia coli Conjugative Plasmid pRK100

Antimicrobial Resistance and Virulence Genes of Escherichia coli Isolates from Swine in Ontario

Loss of Virulence Genes in Escherichia coli Populations during Manure Storage on a Commercial Swine Farm

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