A comparative in silico analysis of the vlhA gene regions of Mycoplasma gallisepticum and Mycoplasma synoviae isolates from commercial hen farms in Mexico

Avian mycoplasmosis, caused by <i>Mycoplasma synoviae</i> and <i>Mycoplasma gallisepticum</i>, poses significant economic challenges due to respiratory issues, reduced egg production and soft eggshells. The variable lipoprotein haemagglutinin (VlhA) protein, crucial for pathogenicity, comprises conserved (MSPB) and variable (MSPA) regions. The aim of this study was to identify the conserved region of <i>vlhA</i> gene sequences in field strain. We examined <i>vlhA</i> sequences from field strains collected in central Mexico (Jalisco and Mexico City). Specifically, we analysed 124 deformed eggs and 10 laying hens from 9 farms with Hy-line and Bovans breeds. Using PCR targeting the <i>mgc2</i> and 16S rRNA genes, we characterized 24 field strains, 4 of which were <i>Myc. synoviae</i> and 20 of which were <i>Myc. gallisepticum</i>. We analysed the <i>vlhA</i> regions, based on the AF035624.1 reference sequence, with American Type Culture Collection strains as positive controls. Additionally, we validated the PCR with 20 negative samples from <i>Mycoplasma</i> isolation without the need for cultivation. We identified two amplification regions: MSPB and MSPA. Bioanalysis revealed relationships between our field samples and avian <i>Mycoplasma</i> sequences in GenBank, alongside similarities with lipoproteins present in <i>Acholeplasma laidlawii</i> PG8 and <i>Escherichia coli</i>. Given the significance of the VlhA protein in pathogenicity and immune evasion, the identified conserved sequences hold potential as therapeutic targets and for phylogenetic studies.