Isolation, Identification and Antimicrobial susceptibility patterns of Pasteurella multocida Isolated from Diseased Rabbits

Pasteurella multocida is a widespread pathogen associated with major animal diseases of considerable economic significance to livestock sector in Egypt. Pasteurella species (spp.) isolated from rabbits are poorly characterized. Therefore, this study was conducted to isolate and study the phenotypic characteristics and antimicrobial susceptibility profiles among P. multocida organisms recovered from diseased rabbits. Isolation of P. multocida was attempted from the collected nasal swabs and tissue samples of rabbits. A total of 16 P. multocida isolates (8%) were recovered from lung tissues and nasal swabs with incidence rates of 6.5 and 1.5%, respectively. The pure cultures were identified on the basis of their cultural, morphological and biochemical properties, pathogenicity studies in rabbits and molecular recognition by a species specific PCR assay. The in vitro antibiotic sensitivity results revealed the occurrence of antimicrobial resistance among all the isolates. The resistance was more frequent to doxycycline, tetracycline and colistin (100% each), followed by erythromycin, cefotaxime, chloramphenicol, ciprofloxacin and trimethoprim/sulfamethoxazole (93.8% each). Meanwhile, low levels of susceptibility were found; with the greatest level of sensitivity to nitrofurantoin (75%). All the examined strains demonstrated remarkably multi-drug resistant (MDR) patterns with resistance to at least 8 drugs. The results of this investigation provide useful information on the diagnosis and antimicrobial resistance patterns of P. multocida for selection of appropriate antimicrobial agents.