POLYMERASE CHAIN REACTION-BASED DIAGNOSIS OF MOLLICUTE INFECTION OF COMMERCIAL ANIMAL SERA

A total of 72 commercial animal sera were assayed for mollicute infection by a polymerase chain reaction (PCR)-based detection method and by four classical detection methods. The methods included microbiological assay by inoculation onto agar and into broth, DNA staining of an indicator cell line with 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) fluorochrome, enzyme-linked immunosorbent assay (ELISA) and adenosine phosphorylase (AdoP) screening. Mollicutes were detected in 2 of the 72 sera assayed. The species isolated was Acholeplasma laidlawii in both cases. When detection methods were compared, PCR, microbiological culture and DNA staining were perfectly concordant. ELISA and AdoP detection produced false-negative results for 1 of the 2 infected sera each. False positive results appeared in 1 of the 70 mollicute-free sera with ELISA and in 16 of the 70 with AdoP detection. It was concluded that the PCR-based detection method is a useful tool in addition to current methods of detection of mollicutes in animal sera, with regard to reliability, sensitivity, specificity and time.