Cutaneous diphtheria masquerading as a sexually transmitted disease.

A 41 year-old, sexually promiscuous, married male, an agricultural laborer by occupation, presented to our sexually transmitted diseases (STD) clinic with multiple ulcers over the scrotum and genitalia of 20 days' duration. Bacterial culture from swabs taken from the genital ulcer, grew organisms morphologically and biochemically characteristic of Corynebacterium diphtheriae. He made a complete and uneventful recovery after two weeks of therapy with antidiphtheria serum and crystalline penicillin. This case brings into light this hitherto unreported presentation of wound diphtheria mimicking a sexually transmitted genital ulcer disease and thus, underlines the importance of considering diphtheria as differential in atypical, long-standing genital ulcers.

[Minocycline]. / Minocycline.

Minocycline belongs to the second generation class of cyclines. It was synthesized in 1967 and marketed in 1972. Minocycline has an antiinfectious activity with a spectrum similar to that of other cyclines, notably against Chlamydias, Treonema and Proprionibacterium acenes. The antiinflammatory activity is associated with this antiinfectious action is greater than that of first generation cyclines with specifically a modulator effect on epidermal cytokines. The pharmokinetics of minocycline is characterized by an excellent absorption, a long half-life and an important lipophilic property inducing good tissue distribution. Clinical trials of minocycline have mainly been performed in sexually transmissible diseases and in acne, a field where randomized studies are the most frequent. These trials show that the effect of minocycline is not stronger than first generation cyclines or doxycycline, but that the action is quicker than that of tetracycline at the dose of 500 mg a day. Minocycline is also efficient in nocardiasis, mycobacteriosis, leprosy, Lyme disease, pyoderma gangrenosum, autoimmune bullous dermatitis, Carteaud disease, and prurigo. However, the effect of minocycline in these different conditions has always been evaluated in open trials with a small number of patients. The usual side effects of cyclines, i.e. digestive problems, fungal infections, are less frequent than with first generation cyclines. No photosensitivity has been demonstrated although pigmentations have been described. Dizziness is a specific side effect of minocycline. Furthermore, rare but severe side effects have been reported, including hypersensitivity syndrome, autoimmune hepatitis, and lupus. Regular indications for minocycline in dermatology are acne and three sexually transmissible diseases (mycoplasm, chlamydia, treponema). Proposed dosage is 100 mg per day in sexually transmissible disease with a reduction to 50 mg per day after 15 days in acne.

Azithromycin and clarithromycin: overview and comparison with erythromycin.

Azithromycin and clarithromycin are erythromycin analogues that have recently been approved by the FDA. These drugs inhibit protein synthesis in susceptible organisms by binding to the 50S ribosomal subunit. Alteration in this binding site confers simultaneous resistance to all macrolide antibiotics. Clarithromycin is several-fold more active in vitro than erythromycin against gram-positive organisms, while azithromycin is 2- to 4-fold less potent. Azithromycin has excellent in vitro activity against H influenzae (MIC90 0.5 microgram/ml), whereas clarithromycin, although less active against H influenzae (MIC90 4.0 micrograms/ml) by standard in vitro testing, is metabolized into an active compound with twice the in vitro activity of the parent drug. Both azithromycin and clarithromycin are equivalent to standard oral therapies against respiratory tract and soft tissue infections caused by susceptible organisms, including S aureus, S pneumoniae, S pyogenes, H influenzae, and M catarrhalis. Clarithromycin is more active in vitro against the atypical respiratory pathogens (e.g., Legionella), although insufficient in vivo data are available to demonstrate a clinical difference between azithromycin and clarithromycin. Superior pharmacodynamic properties separate the new macrolides from the prototype, erythromycin. Azithromycin has a large volume of distribution, and, although serum concentrations remain low, it concentrates readily within tissues, demonstrating a tissue half-life of approximately three days. These properties allow novel dosing schemes for azithromycin, because a five-day course will provide therapeutic tissue concentrations for at least ten days. Clarithromycin has a longer serum half-life and better tissue penetration than erythromycin, allowing twice-a-day dosing for most common infections. Azithromycin pharmacokinetics permit a five-day, single daily dose regimen for respiratory tract and soft tissue infections, and a single 1 g dose of azithromycin effectively treats C trachomatis genital infections; these more convenient dosing schedules improve patient compliance. Azithromycin and clarithromycin also are active against some unexpected pathogens (e.g., B burgdorferi, T gondii, M avium complex, and M leprae). Clarithromycin, thus far, appears the most active against atypical mycobacteria, giving new hope to what has become a difficult group of infections to treat. Gastrointestinal distress, a well known and major obstacle to patient compliance with erythromycin, is relatively uncommon with the new macrolides. Further clinical data and experiences may better define and expand the role of these new macrolides in the treatment of infectious diseases.