What is the antibiotic of choice for treating discharge caused by Haemophilus ducreyi (H ducreyi)?

From the Guidelines

The antibiotic of choice for treating Haemophilus ducreyi infection (chancroid) is azithromycin as a single 1-gram oral dose. This recommendation is based on the most recent and highest quality study available, which suggests that azithromycin is an effective treatment for chancroid 1. Alternative effective regimens include ceftriaxone 250 mg as a single intramuscular injection, ciprofloxacin 500 mg orally twice daily for 3 days, or erythromycin base 500 mg orally three times daily for 7 days.

Key Considerations

• Treatment should be initiated promptly upon diagnosis to prevent complications and further transmission.
• H. ducreyi causes painful genital ulcers and inguinal lymphadenopathy, and effective treatment typically results in symptom improvement within 3-7 days.
• It's essential to also test for and treat other sexually transmitted infections that may coexist with chancroid, particularly HIV, syphilis, and herpes.
• Sexual partners from the 10 days before symptom onset should be examined and treated regardless of symptoms.
• Patients should abstain from sexual activity until lesions are completely healed to prevent transmission.

Rationale

The effectiveness of azithromycin is due to its ability to concentrate in tissues and its long half-life, allowing for convenient single-dose therapy with excellent compliance 1. This makes azithromycin a preferred choice for treating Haemophilus ducreyi infection.

Additional Recommendations

• Patients who are allergic to penicillin should be desensitized and treated with penicillin, as oral form penicillin is not effective.
• The use of doxycycline, minocycline, ceftriaxone, and azithromycin in HIV-infected persons has not been well-studied and must be undertaken with caution.
• Treatment of gonorrhea with quinolones is not recommended in many areas because Quinolone-resistant N. gonorrhoeae continues to spread.

From the Research

Antibiotic Treatment for H ducreyi

The antibiotic of choice for treating discharge caused by Haemophilus ducreyi (H ducreyi) includes:

• Azithromycin, which has been shown to be effective in treating chancroid, a disease caused by H ducreyi, with cure rates of 89% 2 and 91% 3 in different studies.
• Ceftriaxone, which has been compared to azithromycin in the treatment of chancroid, with similar efficacy 3.
• Fluoroquinolones, such as ciprofloxacin and ofloxacin, which have excellent in vitro activity against H ducreyi 4.

Treatment Regimens

Different treatment regimens have been studied, including:

• A single 1 g dose of azithromycin, which has been shown to be effective in treating chancroid 2, 3.
• A single 250 mg dose of ceftriaxone, which has been compared to azithromycin in the treatment of chancroid 3.
• A single oral dose of azithromycin (30 mg/kg), which has been shown to be effective in treating H ducreyi skin ulcers in Papua New Guinea 5.

Special Considerations

Special considerations should be taken into account when treating H ducreyi infections, including:

• HIV-1-infected patients, who may require careful follow-up due to reports of treatment failure with single dose regimens 6.
• Buboes, which may need additional treatment with either aspiration or excision and drainage 6.