The development and application of a Mycoplasma gallisepticum sequence database.

Molecular analysis was conducted on 36 Mycoplasma gallisepticum DNA extracts from tracheal swab samples of commercial poultry in seven South African provinces between 2009 and 2012. Twelve unique M. gallisepticum genotypes were identified by polymerase chain reaction and sequence analysis of the 16S-23S rRNA intergenic spacer region (IGSR), M. gallisepticum cytadhesin 2 (mgc2), MGA_0319 and gapA genetic regions. The DNA sequences of these genotypes were distinct from those of M. gallisepticum isolates in a database composed of sequences from other countries, vaccine and reference strains. The most prevalent genotype (SA-WT#7) was detected in samples from commercial broilers, broiler breeders and layers in five provinces. South African M. gallisepticum sequences were more similar to those of the live vaccines commercially available in South Africa, but were distinct from that of F strain vaccine, which is not registered for use in South Africa. The IGSR, mgc2 or MGA_0319 sequences of three South African genotypes were identical to those of the ts-11 vaccine strain, necessitating a combination of mgc2 and IGSR targeted sequencing to differentiate South African wild-type genotypes from ts-11 vaccine. To identify and differentiate all 12 wild-types, mgc2, IGSR and MGA_0319 sequencing was required. Sequencing of gapA was least effective at strain differentiation. This research serves as a model for the development of an M. gallisepticum sequence database, and illustrates its application to characterize M. gallisepticum genotypes, select diagnostic tests and better understand the epidemiology of M. gallisepticum.