Detection of <i>mycoplasma gallisepticum</i> and <i>mycoplasma synoviae</i> by real-time pcrs and <i>mycoplasma gallisepticum</i>-antibody detection by an elisa in chicken breeder flocks

Abstract

This study aimed to determine the prevalence of Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) in breeder flocks showing respiratory symptoms. A total of 77 flocks (2153 tracheal swabs and blood samples) were sampled and all were tested by MG real time PCR (MG-rPCR) and MG-ELISA, and 32 flocks were tested by MS real time PCR (MS-rPCR). In the first part of this study covering 28 flocks, all samples from chickens with marked clinical symptoms and high MG-antibody levels gave negative results with MG-rPCR(1). Therefore, the MG-lipoprotein gene-specific primers (MG-rPCR(1)) of this PCR were replaced with MG-16S rRNA primers (MG-rPCR(2)), as were the MS-16S rRNA primers (MS-rPCR), thus the study was pursued accordingly. All of the first 28 flocks, which were 100% positive by MG-ELISA, were MG-rPCR(1) negative, whereas in the second part of the study, other 49 flocks, which were 87.8% MG seropositive, were found 42.9% positive by MG-rPCR(2). In addition, 5 selected flocks from the first 28 were negative, whereas 7.4% of the 27 selected flocks from the second 49 were positive by MS-rPCR. Overall, 81 out of 432 MG-rPCR(1-2) (18.7%) performed from 77 flocks, and 13 out of 187 MS-rPCRs (6.9%) in 32 flocks were determined as positive. ELISA results indicated that there could be significantly high false-positives in serological tests, thus results should not be relied upon one test system. Also, this study revealed that, for the confirmation of Mycoplasma-infected flocks in laboratories, rPCR is a reliable method as long as suitable primers are selected, and that MG and MS prevalence is considerably high in winter season.