Toxic effect of sampling swabs and transportation test tubes on the formation of intracytoplasmic inclusions of Chlamydia trachomatis in McCoy cell cultures.

The ability of Chlamydia trachomatis, immunotype E, to produce intracytoplasmic inclusions in cycloheximide-treated McCoy cells after being exposed to different types of sampling swabs in experimentally infected transport medium was studied. A larger number of inclusions was obtained with cotton-tipped aluminium and rayon-tipped plastic swabs than with calcium-alginate-tipped aluminium and cotton-tipped wooden swabs (P less than 0.0001). Transport medium stored in glass tubes caused a cytopathic effect when inoculated on to McCoy cell cultures; no such effect occurred with plastic tubes. When cotton-tipped aluminium instead of calcium-alginate-tipped aluminium swabs were used to collect 50 make urethral specimens significantly more were chlamydia-positive (P less than 0.025). This was also true when cotton-tipped aluminium swabs were used instead of alginate-tipped swabs in a study of 123 cervical specimens (P less than 0.01). When the calcium-alginate-tipped aluminium and cotton-tipped wooden swabs were shaken in the transport medium after sampling from the male urethra and the cervix, instead of being left in the medium during transport to the laboratory, more specimens were chlamydia-positive and a greater number of chlamydial inclusions were found per culture-positive sample; these results were, however, not statistically significant (P greater than 0.05).