<em>Actinobacillus pleuropneumoniae</em> Serotypes by <em>Multiplex </em>PCR Identification and Evaluation of Lung Lesions in Pigs from Piedmont (Italy) Farms

Abstract

Porcine pleuropneumonia (PPP) is one of the main causes leading to massive losses in the pig industry, with high economic impacts. Among different etiological agents, Actinobacillus pleuropneumoniae (APP) is responsible for severe fibrinous-necrotizing pleuropneumonia. A total of 19 different APP serotypes are currently recognized. This study aimed to identify APP serotypes isolated from pneumonic lesions in naturally infected and dead pigs in the Piedmont Region and to describe lesions. A total of 107 dead pigs with a suspected PPP diagnosis were included in this study. Lungs were evaluated using gross pathology scoring systems, APP isolation and serotypes identification by multiplex PCR were conducted. Gross lung lesions were mainly represented by fibrinous pneumonia and pleuropneumonia. APP was isolated in 21/107 (19.6%) samples. On the contrary, PCR indicated APP DNA presence in 53/107 (49.5%) of lung samples. The most observed serotypes were serotype 2 in 24/53 (45.3%) and serotype 6 in 13/53 (24.5%) samples. Moreover, multiplex PCR results suggested a coinfection of different serotypes in 5 samples. This study highlights the relevance of the different techniques application (i.e. bacteriological culture, PCR, gross and histopathology) for improving the identification of APP infections.