Abstract
Transcription-mediated amplification (TMA) enhances detection of Neisseria gonorrhoeae and Chlamydia trachomatis from rectal and pharyngeal sources. The utility of TMA for detection of Trichomonas vaginalis has recently been described. We report on the performance of TMA for detection of sexually transmitted infection (STI) agents from extraurogenital sources, with a focus on T. vaginalis. Within a 21-month interval, 1,314 consecutive male patient encounters at an STI clinic resulted in collection of 2,408 specimens for C. trachomatis, N. gonorrhoeae, and T. vaginalis TMA screening. A total of 471 encounters were managed with a single specimen collection (94.9% urine), with 12.7% positive for at least one STI agent. This detection percentage increased to 14.4% with collection of specimens from two sources and to 20.3% with collection from three sources (P = 0.03 versus single-source sampling). A total of 44.4% of encounters were managed by collection of urine and pharyngeal specimens and 19.1% by the addition of a third (rectal) collection. While procurement of urine and rectal specimens resulted in greater detection of C. trachomatis (6.1% and 11.3% rates, respectively) than of other STI agents, 858 pharyngeal specimens yielded a 2.9% T. vaginalis detection rate compared with 2.1% for N. gonorrhoeae and 1.6% for C. trachomatis. All T. vaginalis pharyngeal detections were confirmed by TMA-based alternative target testing. A total of 38.1% of T. vaginalis-positive pharyngeal specimens were derived from symptomatic patient encounters. A total of 85.7% of males with T. vaginalis-positive pharyngeal collections indicated strictly heterosexual preference. Additional specimen source sampling is necessary to make STI screening comprehensive. Incorporation of extraurogenital sources into assessment for T. vaginalis detection may identify additional symptomatic and asymptomatic male STI carriers.