Isolation, Antibiogram and Molecular Detection of Mannheimia and Pasteurella Associated with Pneumonia in Sheep in Al-Madinah Region, Saudi Arabia

Abstract

Pneumonic pasteurellosis is a common and economically important type of ovine pneumonia. No previous study about the disease in Al Madinah Region, Saudi Arabia. Thus, this study was conducted to determine the association rate of Mannheimia haemolytica and Pasteurella multocida with pneumonia in sheep and to update data about their antimicrobial susceptibility pattern. A total of 100 samples (57 nasal swabs and 43 lung tissues) were collected from diseased and animals suspected to have died of pneumonia. Samples were subjected to bacteriological examination, biochemical identification of isolates by VITEK2 system, direct molecular identification by real-time PCR (RT-PCR), and antibiotic sensitivity testing of isolates. The results showed an overall detection rate of 31% for M. haemolytica (25%) and P. multocida (6%). Only 6% isolates were confirmed by VITEK 2 as M. haemolytica, with probability reached 99%. While, direct molecular method revealed that 20.2% samples were positive for M. haemolytica and 6.4% for P. multocida specific 16S rRNA genes. M. haemolytica isolates were found sensitive to oxytetracycline, nitrofurantoin, trimethoprim/sulfamethoxazole, ciprofloxacin, cefoxitin, ceftazidime, ceftriaxone, imipenem, and tigecycline, in order. While, they were found completely resistant to cloxacillin, streptomycin, and amoxicillin/clavulanic acid. In conclusion, the detection rate of M. haemolytica emphasized its role as a major cause of ovine pneumonia. Besides, our results invigorated the role of direct molecular detection and recommend it for laboratory differential diagnosis. The isolates were resistant to limited antimicrobial agents, nevertheless, the antimicrobial susceptibility test is important for proper treatment.