Isolation and Identification of Porcine Bordetella bronchiseptica and Detection and Analysis of Its Drug Resistance Genes and Virulence Genes in Sichuan Province

PurposeTo understand the prevalence and biological characteristics of Bordetella bronchiseptica in pigs suffering from respiratory diseases in pig farms in Sichuan Province.

MethodsA total of 56 samples were collected to isolate and purify B. bronchiseptica, and screen for drug susceptibility and related drug resistance and virulence genes.

ResultsA total of 10 strains of B. bronchiseptica were isolated, and the isolation rate was 17.86%. The isolates were 100% resistant to penicillin, ampicillin, carbenicillin, lincomycin, co-trimoxazole and cephalexin, and were highly sensitive to neomycin, chloramphenicol, ofloxacin, and levofloxacin. Nine drug resistance genes were detected, among which the detection rate of gyrA, sul1 and tetC exceeded 50%; six virulence genes were detected, among which the detection rate of fla, dnt, prn and fhaB was as high as 100%. The results of the mouse pathogenic test showed that most of the strains had strong pathogenicity.

ConclusionThe multi-drug resistance of the main prevalent B. bronchiseptica in Sichuan Province is serious, the drug resistance mechanism is complex, the coincidence rate of drug resistance genes and drug resistance phenotypes is low, and the detection rate of virulence genes is high. And it showed strong pathogenicity in mice. The research results can provide reference for the prevention, control and treatment of B. bronchiseptica in Sichuan Province.