Capsular typing and antimicrobial susceptibility of Pasteurella multocida from cattle in Afyonkarahisar, Turkey

Pasteurella multocida is primarily recognized as a respiratory pathogen in various animal species. However, sporadic cases of zoonotic infection in humans have also been reported. Understanding the distribution of capsular types is important for improving treatment strategies and developing preventive measures. This study aimed to determine the capsular type and antimicrobial susceptibility profiles of P. multocida isolates obtained from cattle. P. multocida isolates from 650 cattle samples were initially identified by conventional phenotypic methods and subsequently confirmed by PCR. Capsular typing of the isolates was performed using a slide agglutination test and PCR-based capsular genotyping. Of the 48 P. multocida strains typed using the slide agglutination test, 46 (95.8%) were classified as capsular type A, while 2 strains remained untypeable. Genotypic analysis confirmed all isolates as P. multocida via PCR targeting the kmt1 and omp genes. PCR-based capsular genotyping revealed that all 48 isolates belonged to capsular type A. Accordingly, the highest nonsusceptibility rate was observed for OXY (19/48, 39.6%), followed by SXT (11/48, 22.9%), PEN (10/48, 20.8%) and AMC (4/48, 8.3%). Erythromycin was the least effective antimicrobial agent, with a susceptibility rate of 50.0% (24/48) and a resistance rate of 20.8% (10/48). Determining the capsular type and antimicrobial susceptibility profiles of P. multocida isolates may contribute to epidemiological studies and support the development of appropriate treatment strategies. However, further research is needed to elucidate the epidemiological and pathogenic characteristics of P. multocida.