Application of Molecular and Serological Methods for Rapid Detection of Mycoplasma Infection in Chicken Flocks

Abstract

Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are the most significant pathogens of avian mycoplasmosis; therefore their diagnosis is of great importance in the veterinary medicine field. In the present study chicken samples of different ages were tested using conventional isolation methods for detection of MG and MS. The isolates were characterized by using PCR and SDS-PAGE technique and then isolates were tested for antibiotic sensitivity by minimum inhibitory concentration (MIC) method. Moreover, different types of chicken (Breeders, layers and broilers) were tested using conventional isolation methods and PCR for detection of MG and MS and serological tests as SPA and ELISA for detection of antibodies against MG and MS. MG and MS were isolated and it was noted that highest levels of prevalence of both MG and MS isolation was recorded in winter and autumn while lowest in summer and spring. Following the 16srRNA – based detection of Mycoplasma isolates, Different isolates were identified by different PCR-based detection methods for various virulence genes (mgc2 gene, gapA gene andvlhA gene). Duplex PCR mrthod was validated for the simultaneous identification of MG and MS. Using SDS-PAGE, 100% of MG and MS isolates generate common bands at 55 and 17 kDa, respectively. Using MIC method, tiamulin and spiramycin was identified as the antibiotics of choice for the treatment of MG and MS infections, respectively. Highest prevalence of MG was found in commercial layers, followed by breeders, while the lowest prevalence was detected in broilers While for MS the highest prevalence was found in breeders, followed by commercial layers and the lowest prevalence was detected in broilers, By comparing different methods for diagnosis of Mycoplasma infection, It is found that the highest prevalence of MG and MS was detected by Serological tests including SPA test followed by ELISA test and then by PCR and the lowest prevalence was detected by conventional culture method.