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Molecular characterization of enterohemorrhagic Escherichia coli isolates from cattle.

Bakhshi B, Najibi S, Sepehri-Seresht S - J. Vet. Med. Sci. (2014)

Bottom Line: Two different amplification products, which were approximately 750 and 1,700 bp in size, were obtained from amplified variable regions (in-F/in-R primers) in 3 (14.3%) and 4 (19%) of the EHEC isolates, which corresponded to dfrA7(dihydrofolate reductase type I) and dfrA1/aadA1(dihydrofolate reductase/aminoglycoside adenyltransferase) resistance gene cassettes, respectively, and this was confirmed by sequencing.Analysis of pulsotypes showed an extensive diversity among the isolates harboring integron, which is indicative of a lack of any significant genetic relatedness among the isolates.No obvious relation could be deduced between integron content and special pulsotypes.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.

ABSTRACT
A total of 21 (4.3%) enterohemorrhagic E. coli strains were isolated by biochemical tests and identification of the eae(+)stx1(+)stx2(+) genotype from 490 stool samples obtained from calves with diarrhea during 1-year period from a major farm in Tehran, Iran. All of the strains showed resistance to ampicillin, ciprofloxacin, trimethoprim, streptomycin, chloramphenicol and tetracycline, while 19% showed resistance to gentamicin. Out of 21 EHEC strains, 11 (53%) harbored class 1 integron. Two different amplification products, which were approximately 750 and 1,700 bp in size, were obtained from amplified variable regions (in-F/in-R primers) in 3 (14.3%) and 4 (19%) of the EHEC isolates, which corresponded to dfrA7(dihydrofolate reductase type I) and dfrA1/aadA1(dihydrofolate reductase/aminoglycoside adenyltransferase) resistance gene cassettes, respectively, and this was confirmed by sequencing. Genotyping analysis revealed a total of 16 pulsotypes that corresponded to 16 isolates with the similarity indices of 62% and 30% for the most and least similar isolates, respectively, 9 of which harbored class 1 integron. Analysis of pulsotypes showed an extensive diversity among the isolates harboring integron, which is indicative of a lack of any significant genetic relatedness among the isolates. No obvious relation could be deduced between integron content and special pulsotypes. The little data available on the genotyping patterns of EHEC isolates from cattle and their resistance gene contents emphasize the need to establish genotyping databases in order to monitor and source track the source of emergence and spread of new resistant and integron-carrying genotypes.

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UPGMA dendrogram showing banding patterns of XbaI-digestedenterohemorrhagic E. coli isolates. The isolates are presented incomparison with their phenotypic resistance profiles and integron resistance genecontents.
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fig_002: UPGMA dendrogram showing banding patterns of XbaI-digestedenterohemorrhagic E. coli isolates. The isolates are presented incomparison with their phenotypic resistance profiles and integron resistance genecontents.

Mentions: Genotyping analysis: Genotyping patterns were compared using the Dicecoefficient and UPGMA analysis, and the data revealed a total of 16 pulsotypes, whichcorresponded to 16 isolates, 9 of which were harboring class 1 integron. Analysis ofpulsotypes showed extensive diversity among the isolates harboring integron, which isindicative of a lack of any significant genetic relatedness among the isolates. Similarityindices of 62% and 30% were obtained for the most and the least similar isolates,respectively (Fig. 2Fig. 2.


Molecular characterization of enterohemorrhagic Escherichia coli isolates from cattle.

Bakhshi B, Najibi S, Sepehri-Seresht S - J. Vet. Med. Sci. (2014)

UPGMA dendrogram showing banding patterns of XbaI-digestedenterohemorrhagic E. coli isolates. The isolates are presented incomparison with their phenotypic resistance profiles and integron resistance genecontents.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4197144&req=5

fig_002: UPGMA dendrogram showing banding patterns of XbaI-digestedenterohemorrhagic E. coli isolates. The isolates are presented incomparison with their phenotypic resistance profiles and integron resistance genecontents.
Mentions: Genotyping analysis: Genotyping patterns were compared using the Dicecoefficient and UPGMA analysis, and the data revealed a total of 16 pulsotypes, whichcorresponded to 16 isolates, 9 of which were harboring class 1 integron. Analysis ofpulsotypes showed extensive diversity among the isolates harboring integron, which isindicative of a lack of any significant genetic relatedness among the isolates. Similarityindices of 62% and 30% were obtained for the most and the least similar isolates,respectively (Fig. 2Fig. 2.

Bottom Line: Two different amplification products, which were approximately 750 and 1,700 bp in size, were obtained from amplified variable regions (in-F/in-R primers) in 3 (14.3%) and 4 (19%) of the EHEC isolates, which corresponded to dfrA7(dihydrofolate reductase type I) and dfrA1/aadA1(dihydrofolate reductase/aminoglycoside adenyltransferase) resistance gene cassettes, respectively, and this was confirmed by sequencing.Analysis of pulsotypes showed an extensive diversity among the isolates harboring integron, which is indicative of a lack of any significant genetic relatedness among the isolates.No obvious relation could be deduced between integron content and special pulsotypes.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.

ABSTRACT
A total of 21 (4.3%) enterohemorrhagic E. coli strains were isolated by biochemical tests and identification of the eae(+)stx1(+)stx2(+) genotype from 490 stool samples obtained from calves with diarrhea during 1-year period from a major farm in Tehran, Iran. All of the strains showed resistance to ampicillin, ciprofloxacin, trimethoprim, streptomycin, chloramphenicol and tetracycline, while 19% showed resistance to gentamicin. Out of 21 EHEC strains, 11 (53%) harbored class 1 integron. Two different amplification products, which were approximately 750 and 1,700 bp in size, were obtained from amplified variable regions (in-F/in-R primers) in 3 (14.3%) and 4 (19%) of the EHEC isolates, which corresponded to dfrA7(dihydrofolate reductase type I) and dfrA1/aadA1(dihydrofolate reductase/aminoglycoside adenyltransferase) resistance gene cassettes, respectively, and this was confirmed by sequencing. Genotyping analysis revealed a total of 16 pulsotypes that corresponded to 16 isolates with the similarity indices of 62% and 30% for the most and least similar isolates, respectively, 9 of which harbored class 1 integron. Analysis of pulsotypes showed an extensive diversity among the isolates harboring integron, which is indicative of a lack of any significant genetic relatedness among the isolates. No obvious relation could be deduced between integron content and special pulsotypes. The little data available on the genotyping patterns of EHEC isolates from cattle and their resistance gene contents emphasize the need to establish genotyping databases in order to monitor and source track the source of emergence and spread of new resistant and integron-carrying genotypes.

Show MeSH
Related in: MedlinePlus