Targeted Sequencing Analysis Of Mycoplasma Gallisepticum Isolates In Chicken Layer And Breeder Flocks In Thailand.

Abstract

Mycoplasma gallisepticum (MG) is one of the most economically significant pathogens worldwide. MG affects the respiratory system and cause a poor growth performance in poultry. In some developing countries, the conventional PCR assay are still the widely used technique. In this study, 24 collected Thai MG isolates from the unvaccinated farms during 2002-2020 were characterized by gene-targeted sequencing (GTS), followed by phylogenetic using UPMGA analysis. From the results, 24 Thai MG isolates could be differentiated from vaccine strains including F, ts-11 and 6/85. One of Thai MG isolates showed 99.5-100% genetic similarity to F strain with 4 partial genes analysis. The contamination of F strain from the vaccinated farms could be a possible reason because F strain is the most used vaccine strain in Thailand. However, The GTS analysis using the partial MG genes in this study showed that Thai MG isolates were grouped in different patterns based on individual gene sequences. The phylogenetic of partial mgc2, gapA, pvpA and lp gene sequences could classified Thai MG isolates into 7, 11, 7 and 2 groups, respectively. In conclusion, at least 2 partial MG genes especially partial gapA and mgc2 genes should be determined to differentiate the MG isolates.