Treatment of chancroid, 1997

A (p)ppGpp-null mutant of Haemophilus ducreyi is partially attenuated in humans due to multiple conflicting phenotypes

(p)ppGpp responds to nutrient limitation through a global change in gene regulation patterns to increase survival. The stringent response has been implicated in the virulence of several pathogenic bacterial species. Haemophilus ducreyi, the causative agent of chancroid, has homologs of both relA and spoT, which primarily synthesize and hydrolyze (p)ppGpp in Escherichia coli. We constructed relA and relA spoT deletion mutants to assess the contribution of (p)ppGpp to H. ducreyi pathogenesis. Both the relA single mutant and the relA spoT double mutant failed to synthesize (p)ppGpp, suggesting that relA is the primary synthetase of (p)ppGpp in H. ducreyi. Compared to the parent strain, the double mutant was partially attenuated for pustule formation in human volunteers. The double mutant had several phenotypes that favored attenuation, including increased sensitivity to oxidative stress. The increased sensitivity to oxidative stress could be complemented in trans. However, the double mutant also exhibited phenotypes that favored virulence. When grown to the mid-log phase, the double mutant was significantly more resistant than its parent to being taken up by human macrophages and exhibited increased transcription of lspB, which is involved in resistance to phagocytosis. Additionally, compared to the parent, the double mutant also exhibited prolonged survival in the stationary phase. In E. coli, overexpression of DksA compensates for the loss of (p)ppGpp; the H. ducreyi double mutant expressed higher transcript levels of dksA than the parent strain. These data suggest that the partial attenuation of the double mutant is likely the net result of multiple conflicting phenotypes.

Chancroid: clinical manifestations, diagnosis, and management

Chancroid is a sexually transmitted disease (STD) caused by the Gram negative bacterium Haemophilus ducreyi and is characterised by necrotising genital ulceration which may be accompanied by inguinal lymphadenitis or bubo formation. H ducreyi is a fastidious organism which is difficult to culture from genital ulcer material. DNA amplification techniques have shown improved diagnostic sensitivity but are only performed in a few laboratories. The management of chancroid in the tropics tends to be undertaken in the context of syndromic management of genital ulcer disease and treatment is usually with erythromycin. A number of single dose regimens are also available to treat H ducreyi infection. Genital ulceration as a syndrome has been associated with increased transmission of human immunodeficiency virus (HIV) infection in several cross sectional and longitudinal studies. Effective and early treatment of genital ulceration is therefore an important part of any strategy to control the spread of HIV infection in tropical countries.

The effect of treating sexually transmitted diseases on the transmission of HIV in dually infected persons: a clinic-based estimate. Ad Hoc STD/HIV Transmission Group

BACKGROUND

The effect of sexually transmitted disease (STD) treatment on HIV transmission is a topic of considerable current interest and controversy.

GOAL

To assess the potential effect of STD treatment on HIV transmission in persons who are dually infected with STD and HIV.

STUDY DESIGN

Using data from eight STD clinic sites in the United States, the authors estimate the actual achievable reduction in HIV transmission by multiplying the prevented fraction associated with treatment of STDs (set at an average of 0.8) by the maximum potential reduction in HIV transmission achieved by treating STDs (using an average relative risk of 3.0 for increased HIV transmission in the presence of STDs). Subgroup analysis assessed infection proportions for genital ulcer disease, nonulcerative STDs, and any STD by sex, ethnicity, age, and sexual orientation.

RESULTS

The maximum achievable reduction in HIV transmission from dually infected persons to their partners is approximately 33%. The actual achievable reduction is approximately 27% (range, 10.0-38.1%) at the eight clinic sites. If each of the 4,516 dually infected persons in this cohort experienced a single sexual exposure with an uninfected person, 28 HIV infections would occur in the absence of STD treatment whereas 16 infections would occur with STD treatment.

CONCLUSIONS

The estimate of a 27% reduction provides a qualitative assessment of the potential impact of STD treatment on HIV transmission in the absence of any other behavioral intervention. Identification of dually infected persons in STD clinics is an important mechanism for targeting interventions to a social milieu with high risk for HIV infection and other STDs.

The 1998 CDC Sexually Transmitted Diseases Treatment Guidelines

Health care providers who evaluate persons who have or are at risk for sexually transmitted diseases (STDs) should be aware of current national guidelines for STD treatment and should provide assessment and treatment according to these recommendations. The Centers for Disease Control and Prevention STD Treatment Guidelines were developed by using an evidence-based approach incorporating available scientific evidence, specialist knowledge, and consultation with professional organizations and other agencies with diverse perspectives on STD treatment. The guidelines provide recommendations about new antimicrobial agents for the treatment of primary and recurrent genital herpes, a novel patient-applied therapy for genital warts, additional parenteral alternative regimens for the treatment of pelvic inflammatory disease, oral therapy for vaginal candidiasis, and alternative regimens for treatment of chlamydia in pregnancy. Expanded sections in the guidelines also address the management of urethritis, recognition of the acute retroviral syndrome, and the emergence of quinolone-resistant Neisseria gonorrhoeae. Prevention of sexually transmitted hepatitis A and hepatitis B through the use of preexposure vaccinations is discussed.