Sampling and specimen handling in the diagnosis of genital Chlamydia trachomatis infections.

In isolation of Chlamydia trachomatis, special consideration must be paid to the sampling technique, the type and quality of the sampling swab used, and the manner in which transport and storage of specimens are performed. The use of cotton-tipped swabs with aluminum shafts (E.N.T.) rather than calcium alginate-treated endourethral swabs (Calgiswabs), resulted in a higher frequency of isolation of C. trachomatis from clinical specimens. E.N.T. swabs were also preferable to cotton-tipped wooden swabs. In conformity with that finding, a higher chlamydial inclusion count was obtained in cultures of experimentally infected samples stored in contact with such swabs. The percentage of surviving C. trachomatis organisms after storage in transport medium (2-SP) for 2 days at room temperature, or 4 days at 4 degrees C, suggested that such sample storage should be acceptable in the routine diagnosis of genital chlamydial infections.