Identification of Mycoplasma capricolum subspecies capripneumoniae and Mycoplasma arginini by culture, PCR, and histopathology in pneumonic lungs of slaughtered goats in Mashhad, Iran

Background: A number of Mycoplasma spp., often referred to as the Mycoplasma mycoides (Mm) cluster can produce respiratory tract infections in goats; however, only Mycoplasma capricolum subspecies capripneumoniae (Mccp) is considered to causecontagious caprine pleuropneumonia. Aims: Isolation and identification of M. capricoluum subspecies capripneumoniae and M. arginini from the pneumonic lungs of slaughtered goats and their association with pathological changes. Methods: Lungs of 2000 goats slaughtered at an industrial abattoir in Mashhad, Iran, were examined for the presence of gross pneumonic lesions. Fifty affected lungs were selected for pathology, culture, and molecular (PCR) studies for the presence of Mycoplasma species. DNA was extracted from lung tissue samples and replicated using genus and species specific primers for Mycoplasma. Results: Grossly, consolidation and dark red to grey discoloration in the cranioventral to caudal lobes in fibrinopurulent bronchopneumonia and rubbery texture associated with rib impressions on the costal surfaces of the diaphragmatic lobes in interstitial pneumonia were observed. Histopathologically, bronchointerstitial pneumonia in 40 (80%), and fibrinopurulent bronchopneumonia in 10 (20%) of affected goats were diagnosed. The evidence of Mycoplasma growth such as turbidity and Mycoplasma colonies on the Mycoplasma agar plates was observed in 2 (4%) of samples. Genus-specific Mycoplasma DNA was identified in 11 (22%) of samples. Of them, 3 (6%) and 3 (6%) of tissue lung samples were positive for M. capricolum subspecies capripneumoniae and M. arginini, respectively, by PCR. Conclusion: Our results showed that M. capricolum subspecies capripneumoniae and M. arginini were the two agents that can involve lung consolidation and pneumonia in goats.