The aim of the study was to determine if the presence of Trichomonas vaginalis (TV) is associated with an increased risk of coinfection with Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (NG) in female patients presenting to the ED with symptoms consistent with a sexually transmitted disease (STD).

This was a retrospective observational study of female patients tested for the presence of TV by wet mount preparation in the ED from January 1998 through January 2001. Only patients that had the complete results of the wet preparation for TV, DNA probe for CT, and culture for NG were included.

A total of 690 patients were enrolled in the study. Four hundred twenty (61%) patients tested positive for TV by wet mount preparation and 270 (39%) tested negative. Of the 420 TV-positive patients, 41 (9.8%) tested positive for NG, 35 (8.3%) tested positive for CT, and 16 (3.8%) for both. For the 270 TV-negative patients, 16 (5.9%) tested positive for NG, 91 (33.7%) tested positive for CT, and 16 (5.9%) for both. By χ² testing, there was a strong negative association between the presence of TV and coinfection with CT and/or NG. The presence of TV made it 2.9 times less likely to have coinfection with NG and/or CT.

The presence of TV in female patients presenting to the ED with symptoms consistent with an STD is not associated with an increased risk of coinfection with NG and/or CT.