engleski

Effect of autogenous vaccine on the presence of antimicrobial resistance genes in avian pathogenic Escherichia coli strains isolated from broiler breeder farm

Avian pathogenic Escherichia coli (APEC) is one of the most frequent microbial causes of disorders in poultry. Attempts to decrease the prevalence of colibacillosis on poultry farms were based on excessive use of antibiotics that led to the development of multidrug-resistant strains that are hard to eradicate. This study was done on broiler breeder farm that had severe problems with E. coli infection despite the use of commercial vaccines. The use of autogenous vaccine was initiated and the aim was to investigate its effect on the presence of antimicrobial resistance genes of APEC strains on the farm. The study involved two consecutive flocks on the same farm. Flock 1 was vaccinated with commercial E. coli vaccine, while Flock 2 was vaccinated with the autogenous vaccine instead. Liver and peritoneum swabs were taken from 10 and 25 hens from Flock 1 and Flock 2, respectively. Out of positive samples, thirteen isolates from each flock were randomly chosen and examined by paired-end sequencing (MiSeq, Illumina). CGE tool ResFinder was used to detect antibiotic resistance genes. All the isolates carried a mdf(A) gene responsible for resistance to macrolide, lincosamide and streptogramin B. Two isolates from Flock 1 carried sul2 and tet(B) genes responsible for resistance to sulphonamides and tetracyclines, while one isolate from Flock 2 carried drfA5 gene responsible for resistance to trimethoprim. The results show that autogenous vaccines could have some effect on the presence of antimicrobial resistance genes, but the overall effect on the strain shift should be further investigated.

Escherichia coli, APEC, poultry, broiler breeder, autogenous vaccine, antimicrobial resistance

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