Background Sexually acquired rectal infections are common among men who have sex with men (MSM) and increase the risk of HIV acquisition. We aimed to compare the spectrum of pathogens responsible for infectious proctitis between HIV positive and HIV negative MSM.

Methods We undertook a study of MSM who presented to Melbourne Sexual Health Centre with symptomatic proctitis between March 2003 and December 2011. Men with proctitis were tested for gonorrhoea by culture, chlamydia by strand displacement assay, and herpes simplex virus (HSV) by PCR. Chlamydia positive specimens were genotyped for lymphogranuloma venereum (LGV).

Results Among the 279 men in the study, 141 were HIV positive and 138 were HIV negative. The median CD4 count among HIV positive men was 423 (range 189–1026). The prevalence of infections among HIV positive and HIV negative men respectively was: chlamydia (23.4% versus 21.7%, p = 0.7); gonorrhoea (13.4% versus 10.8%, p = 0.5); HSV-1 (14.2% versus 6.5%, p = 0.04); HSV-2 (22% versus 12.3%, p = 0.03); and LGV (7.8% versus 0.7%, p = 0.004). HIV positive men were more likely to have multiple infections (17.7% versus 8.6%, p = 0.017). Only 32% of men with HSV associated proctitis had visible anal ulceration.

Conclusion Among MSM presenting with proctitis, HSV, LGV and multiple infections are more common among HIV positive men than among HIV negative men. MSM presenting with proctitis require comprehensive testing and treatment for possible pathogens including herpes in the absence of anal ulceration.