Molecular Detection of Mycoplasma synoviae Infection in Poultry

Mycoplasma synoviae (MS) is an economically important pathogen of poultry, causing respiratory infection and synovitis in chickens and turkeys. Early detection of MS infection is of critical importance for subsequent prevention and control measures; in this view the present research was undertaken for detection of MS infection in the poultry birds from selected farms of India. A total of 165 choanal cleft swabs from chickens (48 broilers + 117 layers) suspected for Mycoplasma infection were processed for direct detection of MS infection by PCR and cultural isolation. Out of 165 choanal cleft swabs subjected to species specific 16S rRNA PCR, MS was detected in overall 4.2% of specimens with incidence rate of 3.4% and 6.25% in layers and broilers respectively. In vlhA gene PCR, a gene fragment ranging from ~360bp to ~380bp was amplified in all seven 16S rRNA positive samples. The amplicon size varied in samples belonging to different geographical regions i.e. samples from Maharashtra region yielded ~360 bp product whereas from Delhi and Kolkata regions the PCR product was of ~380bp. The blast analysis of sequences of representative sample showed the 99.34% identity with vlhA gene of various MS strains including MS-H strain. The GenBank accession no. MN602747 obtained from NCBI. In cultural isolation all 165 samples including seven PCR positive specimens were turned out to be negative for recovery of MS. Thus, PCR was found to be a rapid, simple, sensitive and cost effective alternative to cultural isolation.