Sexually transmitted diseases: microbiology and management

Anaerobes and bacterial vaginosis in pregnancy: virulence factors contributing to vaginal colonisation

The aetiology and pathogenesis of bacterial vaginosis (BV) is unclear but it appears to be associated with factors that disrupt the normal acidity of the vagina thus altering the equilibrium between the normal vaginal microbiota. BV has serious implications for female morbidity, including reports of pelvic inflammatory disease, adverse pregnancy outcomes, increased susceptibility to sexually transmitted infections and infertility. This paper reviewed new available information regarding possible factors contributing to the establishment of the BV vaginal biofilm, examined the proposed role of anaerobic microbial species recently detected by new culture-independent methods and discusses developments related to the effects of BV on human pregnancy. The literature search included Pubmed (NLM), LISTA (EBSCO), and Web of Science. Because of the complexity and diversity of population groups, diagnosis and methodology used, no meta-analysis was performed. Several anaerobic microbial species previously missed in the laboratory diagnosis of BV have been revealed while taking cognisance of newly proposed theories of infection, thereby improving our understanding and knowledge of the complex aetiology and pathogenesis of BV and its perceived role in adverse pregnancy outcomes.

Treatment of bacterial vaginosis: a multicenter, double-blind, double-dummy, randomised phase III study comparing secnidazole and metronidazole

Objective. Multiple-dose metronidazole oral therapy is currently the reference treatment for bacterial vaginosis (BV). This double-blind, double-dummy, noninferiority study compared the efficacy of secnidazole, another nitroimidazole with pharmacokinetics allowing a single dose regimen, to this standard treatment. Methods. A total of 577 patients were randomized to receive metronidazole (500 mg, b.i.d for seven days) or secnidazole (2 g, once). Therapeutic cure at D28 was defined as the resolution of vaginal discharge, positive KOH whiff test, vaginal pH >4.5 and Nugent score >7 on Gram-stained vaginal fluid. Results. According to this primary endpoint, the single-dose secnidazole regimen was shown to be at least as effective as the multiple-dose metronidazole regimen (60.1 % cured women vs 59.5% , 95% confidence interval with a noninferiority margin of 10%: [−0.082; 0.0094]). Safety profiles were comparable in both groups. Conclusion. The secnidazole regimen studied represents an effective, convenient therapeutic alternative that clinicians should consider in routine practice.

Reexamining syphilis: an update on epidemiology, clinical manifestations, and management

OBJECTIVE

To review the epidemiology, clinical features, diagnosis, and treatment of syphilis.

DATA SOURCES

Studies and reviews were abstracted from MEDLINE (1950-April 2007) using the search term syphilis. All papers were cross-referenced to identify additional studies and reviews for inclusion.

STUDY SELECTION AND DATA EXTRACTION

Pertinent original research articles, review articles, and book chapters were evaluated.

DATA SYNTHESIS

Syphilis is a spirochetal disease that has plagued mankind for centuries. Following a low incidence of syphilis in the US for the last 2 decades, rates are now increasing both in the US and other parts of the world. Once acquired, syphilis can pass through 4 distinct stages of disease: primary syphilis, secondary syphilis, latent syphilis, and tertiary syphilis, with each stage being characterized by different symptoms and levels of infectivity. Diagnosis is made primarily by serologic assays with nontreponemal tests such as the Venereal Disease Research Laboratory and the Rapid Plasma Reagin assay used for screening. Treponemal tests including the Treponema pallidum particle agglutination and the fluorescent treponemal antibody absorption test are then used for confirmation. Recommended treatment regimens are based largely on uncontrolled trials and clinical experience. Penicillin is the treatment of choice, with the preparation and treatment duration varying for different stages. Benzathine penicillin is the treatment of choice for all stages of syphilis except neurosyphilis, for which aqueous crystalline penicillin or procaine penicillin is used due to the central nervous system penetration of these formulations. Coinfection with both syphilis and HIV occurs frequently due to common risk factors. These 2 diseases interact with each other, making both diagnosis and treatment more complicated.

CONCLUSIONS

Clinicians should be aware of the signs and symptoms of syphilis as well as current guidelines for the management and treatment of this disease.

The molecular mechanisms used by Neisseria gonorrhoeae to initiate infection differ between men and women

The molecular mechanisms used by the gonococcus to initiate infection exhibit gender specificity. The clinical presentations of disease are also strikingly different upon comparison of gonococcal urethritis to gonococcal cervicitis. An intimate association occurs between the gonococcus and the urethral epithelium and is mediated by the asialoglycoprotein receptor. Gonococcal interaction with the urethral epithelia cell triggers cytokine release, which promotes neutrophil influx and an inflammatory response. Similarly, gonococcal infection of the upper female genital tract also results in inflammation. Gonococci invade the nonciliated epithelia, and the ciliated cells are subjected to the cytotoxic effects of tumor necrosis factor alpha induced by gonococcal peptidoglycan and lipooligosaccharide. In contrast, gonococcal infection of the lower female genital tract is typically asymptomatic. This is in part the result of the ability of the gonococcus to subvert the alternative pathway of complement present in the lower female genital tract. Gonococcal engagement of complement receptor 3 on the cervical epithelia results in membrane ruffling and does not promote inflammation. A model of gonococcal pathogenesis is presented in the context of the male and female human urogenital tracts.