Isolation of bacterial agents from the lungs of cattle with pneumonia and detection of pasteurella spp. by polymerase chain reaction (PCR)

2.ABSTRACT In this study, lungs of 8222 cattle slaughtered at an abattoir in Elazığ were examined macroscopically and pneumonia was detected, in 500(6.1%) lungs.These samples were inoculated on to blood agar supplemented with 7% sheep blood for isolation of bacterial agents. A Polymerase Chain Reaction (PCR) based upon the use of species-specific primers was carried out on DNA samples extracted from Pasteurella spp. suspicious isolates. In addition, mouse inoculation test was carried out on Pasteurella multocida suspected isolates. A total of 311 (62.2 %) bacterial agents were isolated from the lung samples and were identified as 7.2 % Staphylococcus aureus, 6 % Pasteurella multocida, 6 % Corynebacterium spp, 5.8 % Yeast, 3.8 % Streptococcus spp, 3.6 % Staphylococcus epidermidis, 2.6 % Escherichia coli, 2.2 % Bacillus spp, 2 % Pseudomonas spp, 1.8 % Mannheimia haemolytica, 1.6 % Actinobacillus spp, 1.2 % Klebsiella spp, 0.2 % Moraxella spp, 0.2 % Proteus spp and 18 % mix bacteria in cattle. Twenty four (80 %) of Pasteurella multocida isolates were positive in the mouse inoculation test in cattle. All P. multocida and M. haemolytica strains that were positive by culture were also found to be positive by the PCR. However, toxigenic Pasteurella multocida were not detected in any isolates by PCR using primers derived from toxA gene. In conclusion, this study showed that PCR which is reported to be more sensitive and specific than culture may be used in the identification of Pasteurella spp. as an alternative to conventional testsKey Words: Pneumonia, Cattle, Pasteurella multocida, Mannheimia haemolytica, Polymerase Chain Reaction (PCR).