Chicken erythrocyte Invasion Capability of a <i>Mycoplasma synoviae</i> Strain isolated in Argentina

Résumé

Mycoplasma synoviae is one of the most important pathogens in poultry industry and often causes diseases of a chronic and persistent nature. Little is known about the mechanisms of persistence in the host and the strains differ significantly in invasiveness and pathogenicity. A recent study demonstrated the capacity of M. synoviae to invade chicken erythrocytes (CER). The aim of this study was to determine whether a field M. synoviae strain isolated from an Argentinean laying hen farm has the same cell invasiveness capacity. The test used for this purpose was the gentamicin invasion assay. Samples of chicken erythrocytes in vitro infected with the M. synoviae field strain and control infective strains (M. synoviae WVU 1853 and M. gallisepticum, 14102) were taken 2, 4 and 24 hours after infection, inoculated in Frey broth with or without gentamicin, plated in Frey agar and incubated at 37 ºC for 4-6 days. M. gallisepticum 14102 treated with gentamicin grew well in the agar plates after 2 hours of infection. M. synoviae WVU 1853 and M. synoviae field strain treated with gentamicin grew in the agar plates after 24 hours of inoculation. It is very likely that the strains recovered from the infected chicken cells had invaded the erythrocytes and escaped the mycoplasmacidal effect of gentamicin. This study provides the first evidence of nonphagocytic cell invasion capability of a M. synoviae strain isolated in Argentina.