Chlamydia

Abstract: There is only a small probability that HIV-1 will be transmitted via any single sexual contact. The risk of transmission however during such an act may be greatly increased by the presence of ulcerative genital sexually transmitted disease (STD). Little evidence is published on whether infection with non-ulcerative STD facilitates the transmission of HIV-1. The authors therefore investigated whether treatable STD enhanced the sexual transmission of HIV-1 in a cohort of female prostitutes in Kinshasa Zaire. 431 initially HIV-1-seronegative women were followed prospectively in this nested case-control study for a mean duration of two years in monthly STD check-ups and three-monthly HIV-1 serology. The 68 women who seroconverted were compared against the 126 women who remained HIV-1-seronegative for the incidence of STD and sexual exposure during the presumed period of HIV-1 acquisition. There was a 9.8% annual incidence of HIV-1 in this cohort of subjects. Seroconverters were of mean age 24.6 years compared to 26.8 years for the HIV-seronegative women. During the period of HIV-1 acquisition cases had a much higher incidence of gonorrhea chlamydial infection and trichomoniasis and engaged in unprotected sex with clients and partners more frequently than controls. After controlling for sexual exposure by multivariate analysis adjusted odds ratio for seroconversion were 4.8 for gonorrhea 3.6 for chlamydial infection and 1.9 for trichomoniasis. Genital ulcers were more frequent in cases than controls but much less common than other STD. These findings therefore suggest that non-ulcerative STDs were risk factors for the sexual transmission of HIV-1 in these women. Such STD may be a considerable population-attributable risk in the transmission of HIV-1 worldwide given the high prevalence of non-ulcerative STDs in some populations.

Abstract: Chlamydia pneumoniae (TWAR) is a recently recognized third species of the genus Chlamydia that causes acute respiratory disease. It is distinct from the other two chlamydial species that infect humans, C. trachomatis and C. psittaci, in elementary body morphology and shares less than 10% of the DNA homology with those species. The organism has a global distribution, with infection most common among children between the ages of 5 and 14 years. In children, TWAR infection is usually mild or asymptomatic, but it may be more severe in adults. Pneumonia and bronchitis are the most common clinical manifestations of infection, and TWAR is responsible for approximately 10% of cases of pneumonia and 5% of cases of bronchitis in the United States. The microimmunofluorescence serologic assay is specific for TWAR and can distinguish between recent and past infections. The organism can be isolated in cell culture; however, PCR techniques have recently facilitated its detection in tissues and clinical specimens.

Abstract: See also Editorial by Catchpole Rates of sexually transmitted diseases are increasing, particularly in people aged between 15 and 25. How best to tackle this increase is unresolved, although several tests have recently been developed that are providing new opportunities for screening, early detection, and prevention of sexually transmitted infections and their complications, particularly for Chlamydia trachomatis , herpes simplex virus, and human papillomavirus. Already these tests are being used in research studies, but their introduction into clinical practice raises complex issues. This articles describes the tests that are now available for the major sexually transmitted infections and discusses the important issues they raise in the management of those diseases. We selected topics for inclusion by reviewing specialist journals and conference abstracts from 1998 to 2000. We chose areas that were the subject of most research reports and that are having a direct impact on patient care. We performed a search of Medline for the same period, based on keywords related to these topics. Earlier references were among those quoted in the publications retrieved by the systematic search. We have not considered advances in HIV disease and its management. In the United Kingdom most cases of sexually transmitted infections are treated at genitourinary medicine clinics. Surveillance data from these clinics show that their workload is steadily increasing (fig 1). There has been a noticeable increase in the number of cases of bacterial infections, particularly chlamydia and gonorrhoea since 1995.1 Chlamydia trachomatis is the most commonly diagnosed bacterial sexually transmitted infection in the developed world and a leading cause of pelvic inflammatory disease.2 In 1999, 56 855 patients with uncomplicated chlamydial infection were seen at UK clinics dealing with genitourinary medicine, an increase of 61% since 1996.1 Given the potential for morbidity from ectopic pregnancy and tubal infertility …