The aim of the study was to compare the outcome of syphilis treatment in HIV-infected and -uninfected patients. An observational study on patients diagnosed with early syphilis in three genitourinary clinics in the UK between January 2003 and June 2005 was conducted. Failure of the initial Venereal Disease Research Laboratory (test) (VDRL) titre to decrease four-fold within 12 months in the absence of history of re-infection was considered as treatment failure. During the study period, 190 HIV-uninfected and 129 HIV-infected patients were diagnosed, and 161 (84%) HIV-uninfected and 100 (77.5%) HIV-positive patients with diagnosis of syphilis who had 24 months follow-up syphilis serology results were included in the study (P = 0.10). There were 381 and 508 follow-up episodes for HIV-infected and -uninfected patients, respectively, within 24 months. One HIV-infected patient was diagnosed with neuro-syphilis. After 12 months, 102 (63%) HIV-uninfected and 76 (70%) HIV-infected patients were treated (P = 0.04). On Cox proportional hazard model, successful treatment after 12 months was associated with having VDRL titre more than 1:6 (hazard ratio [HR] 1.011; 95% confidence interval [CI], 1.004-1.019; P = 0.002). Those with negative immunoglobulin M enzyme immunoassay were less likely to have been successfully treated after 12 months (HR 0.676 [95% CI 0.518-0.883]; P = 0.004). HIV sero-status, age, sex group and treatment regimen were not associated with success of treatment. In conclusion, HIV sero-status did not play a role in the outcome of syphilis treatment. Treatment failure in a proportion of HIV-infected patients is due to a slower decline in VDRL titre rather than lack of response to treatment.

Rectal infection with Chlamydia trachomatis affects approximately 7% of men having sex with men (MSM), attending departments of Genito-Urinary (GU) Medicine [Manavi et al. Int J STD AIDS 2004;15:162-4], and the British Association for Sexual Health and HIV (BASHH) guidelines for the treatment of uncomplicated genital C. trachomatis infection include 1 g of single-dose oral azithromycin as a recommended regimen [BASHH 2006]. A retrospective analysis was performed on case-notes from all patients diagnosed with rectal C. trachomatis infection in the department of GU Medicine, Edinburgh for the one-year period from 1 June 2005. Of 101 new episodes of rectal chlamydial infection, only 9% were associated with anorectal symptoms. Excluding these, 85% of asymptomatic patients were treated with a single dose of azithromycin 1 g orally, with a calculated treatment failure rate of 13% (nine of 68). This suggests that single-dose azithromycin may be a less than effective treatment in asymptomatic rectal C. trachomatis infection. The potential treatment failure rate with this regimen emphasizes the need for a test of cure at the appropriate interval following treatment to ensure clearance of infection.

SUMMARY The aims of the study were to determine what microscopic changes occur in the rectal mucosa of men who have had anal intercourse and to correlate the sigmoidoscopic and microscopic appearances. Histological abnormalities were found in 29 of 100 men who attended consecutively a sexually-transmitted diseases clinic. The histopathology of rectal gonorrhoea, as observed in 18 patients, is described as are the microscopic findings in the rectal mucosa of 10 patients with early syphilis. Of 70 men without any detectable rectal infection, biopsies from 15 (21.4%) were abnormal. Intestinal spirochaetosis was observed in biopsies from 36 of these 100 men. With the use of strict criteria to describe the macroscopic appearance of the rectal mucosa, the sigmoidoscopic findings correlated well with the histology.

Enzyme immunoassay (EIA) is an ideal method for screening large numbers of patients for syphilis. We evaluated a novel immune-capture EIA (ICE Syphilis; Murex Diagnostics) that uses three recombinantTreponema pallidum antigens (TpN15, TpN17, and TpN47) and compared the results with those obtained by the native T. pallidum antigen EIA (Captia SelectSyph-G; Centocor) that we currently use for the serodiagnosis of syphilis. Specificity was evaluated by screening 1,184 unselected serum specimens in parallel by the ICE Syphilis and SelectSyph-G assays, while sensitivity was tested with a panel of 101 serum specimens containing antitreponemal antibodies (treated and untreated) from patients with various stages of infection. The specificity of the ICE Syphilis EIA (99.8%) on screening was significantly higher (P < 0.02) than that of the SelectSyph-G EIA (99.2%). The sensitivity of the ICE Syphilis EIA was significantly higher (P < 0.01) than that of the SelectSyph-G EIA on both initial (99 versus 91.4%) and repeat (100 versus 92.4%) testing. The ICE Syphilis EIA was also significantly more sensitive (P < 0.01) than the fluorescent treponemal antibody-abs (92.4%) but not the T. pallidum hemagglutination assay (97.1%). Sera containing antitreponemal antibodies gave a much higher antibody index (absorbance of test serum/kit cutoff) by the ICE Syphilis EIA than by the SelectSyph-G EIA. This combined with the overall high sensitivity makes the ICE Syphilis EIA an ideal test for excluding or detecting treponemal infection in human immunodeficiency virus (HIV)-infected patients. The ICE Syphilis EIA was positive with sera from all 15 HIV-infected patients in the study, whereas sera from 3 HIV-infected patients were negative by the SelectSyph-G EIA. We conclude that the high sensitivity and specificity of the ICE Syphilis EIA and its suitability for automation make it an ideal screening test.

SUMMARY A new enzyme immunoassay (EIA, Captia Syphilis-G) for detecting IgG antibodies against Treponema pallidum was evaluated as a screening test for syphilis. When serum samples were tested at a dilution of 1 in 20 (EIA20), the overall agreement between the IgG EIA and serological status based on the T pallidum haemagglutination assay (TPHA) and the fluorescent treponemal antibody absorption (FTA-ABS) test was 99-2% (1310/1321). The sensitivity of the ETA20 was 98.4% (60/61) and the specificity 99.3% (1251/1260). Discrimination between patients with and without treponemal infection was good: the mean EIA20 absorbance ratios (patient/mean low titre positive control results) were 0.49 for antibody negative patients, 3.30 for patients with positive Venereal Diseases Research Laboratory (VDRL) test and TPHA results, and 1-77 for patients with negative VDRL but positive TPHA results. The cut off point for excluding treponemal infection was taken as 0.9. Specimens with ratios of more than 0.9 should be confirmed by the FTA-ABS test and evaluated for specific IgM antibodies to treponemes. When serum samples were tested at a 1 in 50 dilution (EIA.) the sensitivity was lower (80.3%) but the specificity was absolute. The reduction in sensitivity correlated with low absorbance ratios in the patients who were VDRL negative and TPHA positive.The screening performance of the IgG ETA20 is thus comparable with that provided by a combination ofthe VDRL test and TPHA. The potential for automation makes the EIA an attractive alternative, particularly in larger centres. Alternatively, the test can be performed at a 1 in 50 dilution (ETA50), at which level it is ideally suited for confirming the treponemal status