Comparison of two different primer sets for detection of Pasteurella caballi in bronchoalveolar lavage fluids samples from thoroughbred Arabian foals, using PCR

In the present study, Pasteurella caballi (P. caballi) was isolated and identified in bronchoalveolar lavage fluid and lung samples from thoroughbred Arabian foals using conventional microbiological methods. Subsequently, the ability of two different PCR primer sets was evaluated for detection and confirmation of P. caballi. Primer sets 1 and 2, targeting the 16S rRNA gene of P. caballi, were designed using the Primer 3 and Primer-BLAST programs, respectively. PCR was performed to confirm P. caballi strains and to detect it directly in the bronchoalveolar lavage fluid and lung samples. In total, 35 Pasteurella spp. were isolated from 25 (38.4 %) of 65 bronchoalveolar lavage fluid samples, and 10 (58.8 %) of 17 lung samples. These strains were identified as P. caballi based on conventional microbiological and biochemical characteristics. The sensitivities of primers 1 and 2 were determined to be 100 % to confirm cultured P. caballi strains. However, the specificity of P. caballi detection was lower with primer set-1 than primer set-2 in bronchoalveolar lavage fluid and lung samples. The sensitivity and specificity of primer set-2 were confirmed by gene sequence analysis. This study indicates that the 16S rRNA-PCR method, using primer set-2, provides a rapid and accurate tool for the detection and confirmation of P. caballi isolates in bronchoalveolar lavage fluid and lung samples from foals.