Optimising the conditions for isolation of Mycoplasma gallisepticum collected on applicator swabs

An experiment to compare the recovery of Mycoplasma gallisepticum (Mg) on dry swabs and swabs wet with mycoplasma broth (MB) was carried out by swabbing choanal clefts of Mg infected turkey poults at days 3, 6, 9, 12 post-infection. Wet swabs yielded significantly greater numbers of mycoplasmas than dry swabs on three out of four sampling days. When low numbers of mycoplasmas were collected on wet or dry swabs (in vitro) and then stored at room temperature (RT) or 4°C for various intervals, those on dry swabs at RT had lost viability by 8 to 24 h. They survived at least 24 h on wet swabs kept at 4°C. When Mg was collected and stored on dry and wet swabs from experimentally infected poults survival was again best on wet swabs stored at 4°C. Swabs pre-wet with MB and stored before sampling could be used without any ill effects on mycoplasma recovery as long as they were stored at 4°C and for no more than 48 h. After storage at RT for 48 h such swabs appeared to be detrimental to the organism. Mg collected on wet charcoal swabs was viable for 48 to 72 h when kept at 4°C whereas it was viable for only 24 h when stored at RT. Mg was recovered from wet charcoal swabs sent through the mail but not from dry or wet plain swabs.