Antimicrobial resistance and class 1 and 2 integrons in Escherichia coli from meat turkeys in Northern Italy.

This study is aimed at determining the antimicrobial resistance (AMR) and the presence of class 1 and 2 integrons in 48 avian pathogenic Escherichia coli (APEC) isolated from meat turkeys during 3 sequential production cycles. Thirty avian faecal E. coli (AFEC) from the first cycle were also analysed. Strains were tested for AMR against 25 antimicrobials by disk diffusion test and screened for the presence of integrons and associated gene cassettes by PCR followed by sequencing. Genetic relatedness of isolates was established by pulsed-field gel electrophoresis (PFGE). High levels of resistance were detected to tetracyclines, penicillins and sulphonamides in APEC and AFEC. Resistance to aminoglycosides, fluoroquinolones, cephalosporins and phenicols was variable based on the antimicrobial drug and the isolate (APEC vs AFEC). Full susceptibility to colistin was detected. Multidrug resistance of up to 7 antimicrobial classes was exhibited by APEC (93.8%) and AFEC (100%). Nearly 44% of strains tested positive for class 1 and/or class 2 integrons containing the dfrA, aadA, and sat2 genes, alone or in combination, coding for streptomycin/spectinomycin, trimethoprim and streptothricin resistance, respectively. The estX and orfF genes of unknown function were also detected. A significant association was found between the presence of integrons and the resistance to aminoglycosides and potentiated sulphonamides. The results of this study showed that AMR, multidrug resistance and class...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research