Cost-effective method of triple-site culturing for Neisseria gonorrhoeae

The efficacy of the use of a single modified Thayer-Martin triplate versus that of three separate modified Thayer-Martin plates for the recovery of Neisseria gonorrhoeae from pharyngeal, anal, and genital sites were studied. A total of 98 males and 74 females who showed intracellular gram-negative diplococci on genital Gram stain were studied. Of 172 patients, 164 had gonorrhea at one or more sites. In the first group of 45 males and 21 females, a single swab from each site was used to inoculate randomly both a standard plate (100 mm in diameter) and one-third of a triplate. In the second group of 53 males and 53 females, two swabs were used for collection from each site. One of each pair of swabs was randomly inoculated onto a standard plate and a triplate. There was no significant difference between the results obtained by inoculation with single swabs and those obtained by inoculation with two swabs. There were no significant differences between the positivity rates obtained with the triplate and those obtained with three standard plates used at each site. Cost (39% that of three separate plates) and acceptance by clinic and laboratory personnel make the triplate method an economical, accurate, and effective triple-site screening system.