%0 Journal Article %A P Horner %A D Harte %T P3-S1.37 The role of microscopy in the diagnosis of proctitis among men who have sex with men (MSM). A retrospective review of rectal screening %D 2011 %R 10.1136/sextrans-2011-050108.437 %J Sexually Transmitted Infections %P A280-A280 %V 87 %N Suppl 1 %X Background The rectum is a common site of infection with Chlamydia trachomatis (CT), Mycoplasma genitalium (MG) and Neisseria gonnorrhoeae (GC) among men who sex with men (MSM) who engage in receptive anal intercourse (RAI). Whilst the majority of individuals remain asymptomatic, these infections are likely to induce rectal inflammation which may have implications for HIV transmission. Information regarding the association between rectal CT, MG and GC and proctitis is limited. Objectives To calculate the prevalence of proctitis among a cohort of MSM and investigate the association of proctitis with rectal CT and GC. Methods Data were collected retrospectively. All MSM attending the clinic between July and December 2010 were included. Proctitis was defined as >5 PMNLs per high power field on microscopy of a Gram-stained rectal smear. Information including sexual history, clinical presentation, microscopy and GC/CT NAAT (Aptima combo 2 (AC2)) results were recorded on a proforma. Data were analysed using SPSS 16.0. Statistical tests of association were performed using Pearson's χ2 test. OR were calculated using logistic regression. Results There were 425 MSM who attended for screening in the review period. Of these 83% were UK born. The median age was 32 years (range=16–69 yrs). RAI in the preceding 3 months was reported by 59% (n=251). Of these 64% (n=160) had rectal microscopy performed. Rectal symptoms were reported by 11%. The majority (96%) of samples were collected using a blind rectal swab technique. Proctitis was diagnosed in 23 (14.4%). Of these five were AC2-positive (CT=2, GC=1, CT+GC=1, LGV=1). Rectal AC2 was positive in 19/160 (11.8%) (GC=7, CT=10, CT+GC=1, LGV=1), five of whom had proctitis. Sensitivity and specificity of microscopy for rectal CT/ GC was 26% and 87% respectively. Factors which were predictive of proctitis included rectal symptoms (p=0.001), and being HIV-1sero-positive (p=0.001) but being CT/GC/LGV positive was not associated (p=0.157 OR 2.4; 95% CI=0.8 to 7.5). Conclusion Proctitis is common among MSM, particularly HIV-1 seropositive men. The association with GC/CT infection was weak. The causes of and relevance of proctitis remain poorly understood and further research is warranted. %U https://sti.bmj.com/content/sextrans/87/Suppl_1/A280.1.full.pdf