Case reports involving coinfection with Avibacterium paragallinarum and Ornithobacterium rhinotracheale in broiler chickens and Avibacterium endocarditis in broiler breeding hens in Poland

Abstract

The study describes three clinical cases of infection with Avibacterium spp.. In case no. 1, respiratory clinical signs and high mortality (0.7–4.2% daily; total 21.2%) in broiler chickens Ross 308 were shown to be caused by coinfection with sequence type 9 of O. rhinotracheale presumptive serotype A and A. paragallinarum presumptive serotype B. The identical PFGE restriction pattern (pulsotype) of seven A. paragallinarum isolates indicated that infectious coryza (IC) in broilers was caused by the same clone. In cases 2 and 3, sudden increased deaths in boiler breeders Ross 308 (especially males) with lesions in the endocardium (valvular or mural endocarditis) were shown to be caused by A. endocarditis. Among nine antibiotics tested, florfenicol was the only antibiotic to which all of A. paragallinarum and O. rhinotracheale isolates were susceptible. Out of the eight antibiotics tested, eleven A. endocarditis isolates from both clinical cases of infective endocarditis (IE) were susceptible to penicillin, amoxicillin, doxycycline and florfenicol. The A. endocarditis isolates tested in both clinical cases had different PFGE patterns (pulsotypes), but identical within a case. The causes of IC and IE in the cases presented have not been determined. In the prevention of infectious diseases in large-scale livestock farming, it is very important to follow the rules of biosecurity.