Comparison of the in vitro activities of various parenteral and oral antimicrobial agents against endemic Haemophilus ducreyi

Single-Dose Azithromycin for the Treatment of Haemophilus ducreyi Skin Ulcers in Papua New Guinea

Background

Haemophilus ducreyi (HD) and Treponema pallidum subspecies pertenue (TP) are major causative agents of cutaneous ulcer (CU) in the tropics. Azithromycin is recommended to treat sexually transmitted HD infections and has good in vitro activity against HD strains from both genital and skin ulcers. We investigated the efficacy of oral single-dose azithromycin on HD-CU.

Methods

We conducted a community-based cohort study in Lihir Island, Papua New Guinea, from October 2014 through May 2016. Consenting patients with skin ulcers >1 cm in diameter were eligible for this study and had collected a lesional swab for polymerase chain reaction (PCR). All participants were treated with single-dose azithromycin (30 mg/kg) and were followed up for assessment of clinical resolution. We retrospectively classified patients according to PCR results into HD, TP, and PCR-negative groups. The primary endpoint was healing rates of HD-CU at 14 days after treatment.

Results

We obtained full outcome data from 246 patients; 131 (53.3%) were HD PCR positive, 37 (15.0%) were TP positive, and 78 (31.7%) were negative for all tests. Healing rates were 88.5% (95% confidence interval [CI], .82-.93) in the HD group, 78.4% [95% CI, .63-.89] in the TP group, and 74.4% (95% CI, .64-.83) in the PCR-negative group. If we included the participants with improved ulcers, the healing rates increased to 94.7%, 97.3%, and 89.7% respectively. HD cases classified as not healed all converted to HD-negative PCR.

Conclusions

Based upon clinical resolution and PCR conversion to HD negative, a single oral dose of azithromycin is efficacious for the treatment of HD-CU. These results have implications for the treatment of individual patients and for the use of antibiotics in public health strategies to control CU in the tropics.

Chronic cutaneous ulcers secondary to Haemophilus ducreyi infection

Haemophilus ducreyi is a well recognised causative agent of genital ulcers and chancroid. We report two unusual cases of non-sexually transmitted H. ducreyi infection leading to chronic lower limb ulcers. Both patients were Australian expatriates visiting Australia from the Pacific Islands--one from Papua New Guinea and the other from Vanuatu.

Selected sexually transmitted diseases and their relationship to HIV

Although sexually transmitted diseases (STDs) are underreported and underrecognized, they are a major source of morbidity, mortality, and represent a major socioeconomic cost in developing and industrialized nations. Individuals who develop STDs are often coinfected with human immunodeficiency virus (HIV). Coinfection with HIV both facilitates the natural history of STDs and worsens the clinical picture. The objective of this article is to provide a review to the practicing clinician on the epidemiology, clinical manifestations, methods of diagnosis, and treatment for four cutaneous STDs--chancroid, genital herpes, granuloma inguinale, and lymphogranuloma venereum--in coinfected HIV patients.

Sexually transmitted diseases update

STDs have worldwide distribution and result in immense social and economic cost. Knowledge of the clinical signs, symptoms, current clinical tests, and treatment recommendations is important for all health care professionals.

Chancroid and Haemophilus ducreyi: an update

Haemophilus ducreyi is a fastidious gram-negative bacillus that causes the sexually transmitted infection chancroid. Chancroid is a major genital ulcerative disease in Africa, Southeast Asia, the Caribbean, and Latin America and is of increasing concern in the United States. Genital ulcerative disease and chancroid in particular have been associated with facilitating the transmission of human immunodeficiency virus. The diagnosis of chancroid based on the clinical appearance of the genital lesion or on the isolation of H. ducreyi on selective medium is relatively insensitive. However, recent advances in nonculture diagnostic tests have enhanced our ability to diagnose chancroid. There has been renewed interest in understanding the pathogenesis of H. ducreyi. In vitro and in vivo models have been developed to help identify important virulence determinants. Through the use of biochemical and molecular techniques, macromolecular components that may be important in virulence have been identified.

Quinolones in sexually transmitted diseases. Global experience

The role of quinolones in sexually transmitted diseases is still being defined. In vitro and in vivo efficacy of established agents against gonorrhoea after a single oral dose is well established, although problems with emerging resistance have been identified. However, among these agents only ofloxacin is reliably active against Chlamydia trachomatis infection, and only as a course of treatment. Preliminary trials with sparfloxacin are encouraging. Other new agents show potentially useful in vitro activity, but clinical studies are awaited. To date, clinical activity of quinolones in bacterial vaginosis has been disappointing. The efficacy of newer agents with anaerobic activity will be of interest. Chancroid can be cured with ciprofloxacin or ofloxacin; resistance has been reported, but is not yet clinically significant. Ofloxacin appears to be effective therapy for pelvic inflammatory disease, without the need for additional anaerobe cover. The possibility of improved clinical efficacy justifies further in vitro and in vivo studies.

Emergence of Haemophilus ducreyi resistance to trimethoprim-sulfamethoxazole in Rwanda

The in vitro susceptibilities of 112 clinical isolates of Haemophilus ducreyi to six antimicrobial agents were determined. These isolates were obtained in Kigali, Rwanda, during three studies on genital ulcer disease performed in 1986 (18 isolates), 1988 (23 isolates), and 1991 (71 isolates). All H. ducreyi isolates were susceptible to azithromycin, ceftriaxone, ciprofloxacin, and erythromycin; all isolates obtained in 1986 were also susceptible to trimethoprim and to the combination trimethoprim-sulfamethoxazole. In contrast, 39 and 9% of the isolates obtained in 1988 and 59 and 48% of the isolates obtained in 1991 were resistant to trimethoprim (MIC, > or = 4.0 mg/liter) and trimethoprim-sulfamethoxazole (MIC, < or = 4.0/76 mg/liter), respectively. These data indicate that trimethoprim-sulfamethoxazole can no longer be recommended for use in the treatment of chancroid in Rwanda, and possibly elsewhere in Africa.