[Pristinamycin versus oxacillin in the treatment of superficial pyoderma. A multicenter randomized study in 293 outpatients].

BACKGROUND

Superficial pyoderma occurs frequently. Generally, the benign infection is caused by Staphylococcus aureus and/or a group A streptococci. The subject is controversial, but treatment usually is based on narrow-spectrum antibiotics active against both germs.

PATIENTS AND METHODS

A multicentric, randomized, double-blind, double-placebo study was conducted to compare pristinamycin (1 g b.i.d.) with a reference antibiotic, oxacillin (1 g b.i.d.) for 10 days. Inclusion criteria were: both sexes, age 15-80 years, clinical diagnosis of superficial pyoderma (impetigo, wound infection within the last 15 days, furunculosis, carbuncle, perionyxis), informed consent. The general practitioner investigators (n = 52) were assisted by 9 dermatologist-coordinators. Clinical diagnosis was validated by a committee of experts at the end of the study after analyzes of the photos and bacteriological results obtained on samples taken at the practitioner's office on visit 1 (D0), visit 3 (D14 +/- 3) and visit 4 (D25 +/- 3). Successful treatment was defined by clinical, bacteriological and photographic efficacy at visit 3 (equivalence analysis: one-way 95 p. 100 confidence interval).

RESULTS

There were 293 included patients given pristinamycin (n = 151) or oxacillin (n = 142). Mean age of analyzed patients was 40 +/- 17 years. Diagnosis was confirmed in 255 patients in accordance with the protocol: furunculosis or carbuncle (n = 100), recently superinfected wound (n = 97), impetigo (n = 41), acute perionyxis (n = 17). Thirty-five patients (12 p. 100) were considered to have been wrongly included. The germs most often isolated were: Staphylococcus aureus (n = 126), group A streptococci (n = 13), group B streptococci (n = 5) and P. multocida (n = 3). At visit 3, the two treatments were found to be equivalent with a success rate of 86.7 p. 100 for pristinamycin and 89.8 p. 100 for oxacillin (CI [*9.97]). Tolerance was statistically comparable between the two treatments (27 to 32 percent minor side effects).

DISCUSSION

This study is the first performed in outpatients attended by general practitioners with diagnostic confirmation on both bacteriological and photographic evidence of superficial pyoderma. The results obtained demonstrate the good reliability of such studies although 12 p. 100 of the patients were wrongly included, a factor which should be taken into account for future studies. The efficacy and tolerance of pristinamycin were statistically equivalent to those of oxacillin for all the patients with superficial pyoderma. Nevertheless, the subgroup of patients with folliculitis gave rather heterogeneous bacteriology and therapeutic results.