Prevalence, Molecular Identification, and Antimicrobial Resistance Traits of Pasteurella multocida Isolated From Nasal Swabs of Buffaloes in Bangladesh.

Pasteurella multocida is an important bacterial respiratory pathogen of buffaloes and may cause major economic losses in the livestock sector. But there is a lack of data on its prevalence, risk factors, and antimicrobial resistance patterns in Bangladesh. The study was cross-sectional, and a total of 400 buffaloes from seven locations in Bangladesh were included in the nasal swab collection. Isolation was done using culture methods and confirmed by polymerase chain reaction (PCR). Associations between infection and risk factors were explored using logistic regression analysis; antibiotic susceptibility was determined by the disc diffusion method. The co-resistance patterns were assessed by Pearson's correlation analysis. The culture-based prevalence of P. multocida was 12.25%, compared with a PCR-confirmed prevalence of 7.25%; all PCR-positive isolates were capsular type B, with notable regional variation in prevalence. Buffaloes with respiratory symptoms had significantly greater odds of being infected (OR = 8.88, p < 0.001), and the younger group of animals aged 1-3 years had a greater predisposition to infection than the younger ones, but sex was not significantly associated with infection. The isolates exhibited high antibiotic resistance, as demonstrated by antimicrobial susceptibility testing, particularly against ampicillin (96.55%), oxytetracycline (93.10%), and penicillin-G (89.65%). Cefixime (93.10%) and azithromycin (68.96%) remained largely effective by contrast. Positive correlations were identified between resistance to β-lactams, tetracyclines, and aminoglycosides. These findings suggest that multidrug-resistant P. multocida type B is circulating in buffaloes in Bangladesh and highlight the need for increased surveillance, rational use of antimicrobials, and integrated control strategies.