Our hypothesis is that nucleic acid amplification testing (NAAT) with the APTIMA Combo2 (AC2) will have greater sensitivity than culture in detecting Neisseria gonorrhoeae in rectal samples. We also hypothesize that AC2 will be equivalent to NAAT with the Becton Dickinson ProbeTec in detecting Chlamydia trachomatis and Neisseria gonorrhoeae in rectal samples.

This research is being done to compare the results of tests for diagnosing sexually transmitted infections (STI) from rectal samples. Specifically, this study will test for gonorrhea and Chlamydia from rectal samples and compare the results between standard culture and newer technology (nucleic acid amplification testing otherwise know as "NAAT") used to detect these infections. Gonorrhea and Chlamydia are STIs (infections you get from having sex with someone who is infected). Infections in the rectum may cause symptoms such as rectal discharge, itching and/or pain or may be asymptomatic (no symptoms present). Since these infections are sexually transmitted, it is important to have accurate tests to diagnose and treat these infections to prevent them from being passed onto a sexual partner.

NAAT has not been Food and Drug Administration (FDA) approved for use in diagnosing these infections in the rectum. The tests are approved to detect these infections from other sites (cervix and urine) and investigators believe that these tests will be very accurate in detecting these infections in the rectum as well. This study will validate the use of NAAT in rectal samples so that this technology can be used in our research laboratory for future studies that involve testing for STIs from the rectum.

There are times when people have signs of inflammation in the rectum (known as proctitis) and an infection or cause is not able to be identified. Investigators believe that this new technology (NAAT) may be able to find reasons (different bacteria) for infection that were not able to be identified with older testing methods. By participating in this study, one of the rectal swabs will also be tested for additional bacteria (called Mycoplasma and Trichomonas). Both of these organisms are sexually transmitted and may be important organisms in the cause of proctitis.

Inclusion Criteria:

1. Male and female subjects aged 18 and older
2. Women or men who have a history of engaging in receptive anal intercourse
3. Willing to provide written informed consent for participation in this study

Exclusion Criteria:

1. Use of oral antibiotics in the past 7 days
2. Use of rectal douche or other rectal product in the past 24 hours

Women (n=175) and men who have sex with men (n=224) with a lifetime history of anal intercourse by self-report