Correlation between the presence of enzootic pneumonia lesions and detection of Mycoplasma hyopneumoniae in bronchial swabs by PCR

In many diagnostic laboratories the diagnosis of mycoplasmal pneumonia in p igs is based on clinical signs and the presence of gross and histopathologi cal lesions. The objective of this study was to evaluate the nested-PCR tec hnique as an adjunct to the histopathological diagnosis of Mycoplasma hyopn eumoniae infection. Respiratory disease of 184 swine cases submitted to the Minnesota Veterinary Diagnostic Laboratory between 1 January and 30 June 1 998 were used. Bronchial swabs were collected and the nested-PCR performed. Lung samples were graded PCR positive or negative. Histopathological lesio ns were scored 0-4, depending on the mycoplasma-like characteristics of the lesions, with category 4 demonstrating strong evidence of mycoplasma infec tion. Nested-PCR correlated well with histopathological lesions characteristic of M. hyopneumoniae in categories 3 and 4 and approximately half of the histo pathological categories 1 and 2 were nested-PCR positive. The results demon strate that the nested-PCR is a valuable adjunct in the diagnosis of M. hyo pneumoniae infection when non-diagnostic microscopic lesions of mycoplasmos is are found. (C) 2000 Elsevier Science B.V. All rights reserved.