Gene Targeted Sequencing Analysis of Mycoplasma gallisepticum Strains in Poultry Flocks from Middle East and South Asia

Abstract

The aim of this study was to attempt the molecular characterization of Mycoplasma gallisepticum (MG) strains detected in chicken flocks from United Arab Emirates (UAE), Saudi Arabia (SAU) and Sri Lanka (SL). Between 2012 and 2015, 55 samples from one layer flock from UAE, three breeder flocks from SAU and one broiler flock from SL were screened for MG using a pr-mgc2 PCR; the positive samples were characterized by the gene-targeted sequencing (GTS) analysis. BLAST comparisons, followed by phylogenetic analysis, was carried out to compare the obtained sequences against published vaccine and field strain sequences. Fifty of the fifty-five (91%) examined samples, were MG positive by pr-mgc2 PCR. The sequences detected in the samples from ts-11 vaccinated breeders from SAU showed 100% identity with the ts-11 vaccine sequences. The sequences detected in the samples from layers in UAE, were attributed to field strains, clustering together with Israeli MG strains. The sequences obtained from the samples from Sri Lanka broilers clustered separately from USA, Israeli, Australian, vaccine and reference strains. A potential route of MG field infection to the examined flocks may have been through the movement of birds, either directly (flock-to-flock transmission) or indirectly (through wild bird transmission). To our knowledge, this study reports the first molecular characterization by gene-targeted sequencing (GTS) analysis of MG strains from commercial poultry in SAU, UAE and SL.