ARS | Publication request: Characterization of Antimicrobial Resistance Determinants among Salmonella, Campylobacter, Escherichia, and Enterococcus using PCR and Microarray Approaches

Submitted to: Interscience Conference on Antimicrobial Agents & Chemotherapy Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 25, 2008
Publication Date: September 25, 2008
Citation: Fry, P., Abley, M., Kaydos-Daniels, S., Cray, P.J., Frye, J.G., Wondwossen, G. 2008. Characterization of Antimicrobial Resistance Determinants among Salmonella, Campylobacter, Escherichia, and Enterococcus using PCR and Microarray Approaches. Interscience Conference on Antimicrobial Agents & Chemotherapy Proceedings. October 25 - 28, 2008. Washington, DC. CD - ROM. C2 - 3926.

Technical Abstract: Salmonella, Campylobacter, Escherichia, and Enterococcus can be important carriers of antimicrobial resistance. Limited work has been done to examine the relationship among strains co-cultured from the gastrointestinal tract of individual animals. To address this, 1284 isolates were collected from swine and isolates collected from the GI tract of the same subjects were analyzed using antimicrobial susceptibility. DNA microarray was performed on 19 selected MDR isolates, while PCR and DNA sequencing of specific resistance determinants was done on 128 isolates. Multiple organisms from the same animal were found to carry tetA(B), strA, strB, and aphA1-Iab. StrB and aphA1-Iab from Salmonella and E. coli were e 98.6% homologous. Microarray analysis showed that 47.3% of resistance genes detected was found in at least two different bacterial organisms. Class-1 integrons were found in 18.2% of the isolates. A unique large class 1 integron (4 kb) carrying the dfra16, blaPSE-1, aadA2 and ereA resistance genes were found in Salmonella serovar Havana. The very high homology of resistance genes found within the four organisms may be the result of horizontal gene transfer within the host. This data will be used to help develop strategies to prevent this horizontal transfer.