Prevalence of class 1 and class 2 integrons in poultry processing and a natural water ecosystem

Abstract

Integrons are genetic elements that regulate the uptake and expression of antimicrobial resistance, as well as other pathogenic genes. These genetic elements have been previously reported in poultry microflora but the research to date has been primarily based on selective culture methods. In this work, the use of molecular methods are applied to identify integrons in poultry processing. Total microbial DNA was extracted from poultry processing microflora and examined using a Polymerase Chain Reaction (PCR) methodology to more sensitively examine the prevalence and characteristics of class 1 and class 2 integrons within this environment. Class 1 and class 2 integrons of various sizes were found throughout all stages of poultry processing, including chiller tank samples and retail poultry samples. The level of prevalence of these integron elements has not been previously reported, indicating the increased sensitivity of the molecular approach. Within the natural water ecosystem integrons of all classes have not been widely explored. In this study, we utilized previously catalogued Escherichia coli isolates from the Rio Grande River and determined antimicrobial resistance profiles to determine resistance prevalence. Again, a PCR methodology was utilized to determine if multiple antimicrobial resistance in these isolates was related to the presence of the class 1 and class 2 integrons. Both classes of integrons were found in multiple antimicrobial resistant isolates and sequencing of these integron variable regions indicated a highly conserved aadA gene suggesting the integrons found were related to transposon linked integrons previously reported.