The influence of type of swab and laboratory method on the recovery of Mycoplasma gallisepticum and Mycoplasma synoviae in broth medium.

Swabs are often used to collect material for avian mycoplasma culture. Such swabs, when inoculated into broth medium, are usually discarded prior to incubation of the broth. In this study the effect on growth of low numbers of Mycoplasma gallisepticum and Mycoplasma synoviae was compared in broths with and without retention of the swab. Plain or charcoal cotton swabs on wooden or plastic sticks were more likely to give growth if retained in the medium for incubation, but rayon swabs on aluminium wire caused inhibition of growth. It was shown that despite thorough agitation of the swab in the broth, cotton and rayon swabs could retain a large percentage of the total numbers of colony-forming units.