Improvement of specific polymerase chain reaction (PCR) for the identification of Mycoplasma capricolum subsp. capripneumoniae
A polymerase chain reaction (PCR) test for the identification of Mycoplasma capricolum subsp. capripneumoniae (Mccp) was optimized using the H2 gene sequences of M1601. The test was evaluated on 20 strains including six representative strains of the Mycoplasma mycoides cluster as well as 13 field isolates from China, Pasteurella multocida and Mannheimia haemolytica. To obtain a test that was specific for Mccp, the PCR produced an amplicon of approximately 680 bp only with the Mccp strains. The specificity of the present PCR was found to be 100% specific for Mccp. The sensitivity of the PCR showed that it could detect a minimum of 0.75 ng of purified DNA. For further evaluation, clinical samples tested by PCR included lung and liquor pleurae from 14 goats artificially infected with Mccp. The PCR was positive in all the clinical samples both in the undiluted and 50-fold dilutions of extracted DNA except for a sample of liquor pleurae. However, the latter showed weak bands. An epidemiological survey was also performed using the constructed PCR methods and results indicated that 36 of 61 of these samples including tissue and percolate from Western China were considered positive. The coincidence rate was 82% compared with the performance of a PCR test earlier published. The present PCR represents a rapid and reliable method for genetically based identification of Mccp. The specificity of the test makes it suitable for detection of Mccp in clinical samples.
Key words: Mycoplasma capricolum subsp. capripneumoniae, PCR, identification.