Recovery of Chlamydia and Genital Mycoplasma transported in sucrose phosphate buffer and urease color test medium

Urethral swabs from 75 males with urethritis were extracted into tryptose phosphate broth and then equal aliquots were dispensed into vials containing sucrose phosphate buffer (2SP) and urease color test medium (U-9). No antibiotics were present in the media. After transport to the laboratory, the recovery of Chlamydia trachomatis and Ureaplasma urealyticum was evaluated after inoculation into McCoy's cell cultures and agar medium, respectively. C. trachomatis was recovered from significantly more patients (17 versus 12, P = 0.03) with higher inclusion counts (P less than 0.01) in specimens transported in 2SP as compared with those in U-9 medium. No significant differences between the isolation rate of U. urealyticum and that of Mycoplasma hominis were found with the two media. The rate of inactivation of C. trachomatis and U. realyticum at 4 C was examined by means of reference strains. The inactivation of C. trachomatis was similar in both 2SP and U-9 media, but the number of inclusions was consistently greater in the 2SP medium. In contrast, the number of colony-forming units of U. urealyticum actually increased over a 24-hour period in both media. We conclude that 2SP is the best medium for the combined recovery of C. trachomatis and genital Mycoplasma. The use of one transport medium and hence a single swab culture has the obvious advantages of saving time and expense for both physician and laboratory, and for the patient it will eliminate the possible discomfort of having multiple cultures taken.