Microarray analysis of antimicrobial resistance genes inSalmonella entericafrom preharvest poultry environment

Abstract

To detect antimicrobial resistance genes in Salmonella isolates from turkey flocks using the microarray technology. A 775 gene probe oligonucleotide microarray was used to detect antimicrobial resistance genes in 34 isolates. All tetracycline-resistant Salmonella harboured tet(A), tet(C) or tet(R), with the exception of one Salmonella serotype Heidelberg isolate. The sul1 gene was detected in 11 of 16 sulfisoxazole-resistant isolates. The aadA, aadA1, aadA2, strA or strB genes were found in aminoglycoside-resistant isolates of Salm. Heidelberg, Salmonella serotype Senftenberg and untypeable Salmonella. The prevalence of mobile genetic elements, such as class I integron and transposon genes, in drug-resistant Salmonella isolates suggested that these elements may contribute to the dissemination of antimicrobial resistance genes in the preharvest poultry environment. Hierarchical clustering analysis demonstrated a close relationship between drug-resistant phenotypes and the corresponding antimicrobial resistance gene profiles. Salmonella serotypes isolated from the poultry environment carry multiple genes that can render them resistant to several antimicrobials used in poultry and humans. Multiple antimicrobial resistance genes in environmental Salmonella isolates could be identified efficiently by microarray analysis. Hierarchical clustering analysis of the data was also found to be a useful tool for analysing emerging patterns of drug resistance.