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EFFICACY OF THREE-DAY AZITHROMYCIN VS. TEN-DAY PENICILLIN V IN THE TREATMENT OF STREPTOCOCCAL PHARYNGITIS

1997; Lippincott Williams & Wilkins; Volume: 16; Issue: 5 Linguagem: Inglês

10.1097/00006454-199705000-00033

1532-0987

Lucia Pacifico, Claudio Chiesa,

Infective Endocarditis Diagnosis and Management

To The Editors: Schaad et al.1 recently reported the results of a multicenter comparative study of 3-day azithromycin vs. 10-day penicillin V in the treatment of group A beta-hemolytic streptococcal (GABHS) pharyngitis. We wish to bring up some critical issues regarding the paper. We found their results interesting in a way that confirms our previous findings2 on the significantly lower eradication of GABHS with a 3-day course of azithromycin compared with a 10-day course of penicillin V. However, we are concerned with their incorrect and misleading commentary on our published comparative evaluation. The investigators leave the reader with the implication that in our randomized trial patients with pretreatment azithromycin-resistant GABHS isolates were included in the efficacy analysis of azithromycin treatment. Against such a statement the reader should know that azithromycin-treated patients with initial GABHS strains resistant to azithromycin were disqualified from the efficacy analysis. Thus our reported 46% rate of azithromycin failure in eradicating GABHS azithromycin-susceptible strains is in accordance with the 45% rate reported by Schaad et al. The authors argue eloquently that their encountered 45% microbiologic failure after treatment with 3-day azithromycin might have been related to a possible bias between the two treatment groups in carrier contamination. Although GABHS carriage is probably the most troublesome issue for both the clinician and the researcher, the authors failed to take into account that there are symptom-free children with bona fide GABHS infection, just as there are carriers of GABHS with symptoms (presumably from an intercurrent viral infection).3 No attempt was made in their study to demonstrate any serologic evidence of GABHS infection or to quantitate follow-up throat cultures in either treatment group. When comparing our previous microbiologic results with those obtained by Schaad et al., it is very surprising that in both studies GABHS carriers chanced to be represented with the same percentage in the azithromycin-treated group of children. In their study the final assessment of bacteriologic efficacy was targeted toward the occurrence of positive follow-up throat cultures regardless of the GABHS serotype isolated. If the authors had excluded from their bacteriologic analysis patients with a different serotype of GABHS on the follow-up throat culture, their results of bacteriologic inefficacy of azithromycin vs. penicillin at a mean follow-up of 25 days (41 of 93 azithromycin-treated patients, 18 of 120 penicillin V-treated patients) would have reported as a level of significance a P value of <0.0001 (in agreement with the P value we previously reported2) instead of a P value < 0.001. We have reservations concerning the method used for establishing the overall clinical success. In this respect their methodology included two control visits at a mean follow-up of 12 and 25 days, respectively, and a retrospective questionnaire for up to 6 months. It is unclear to us why the authors surprisingly neglected in the prospective assessment of clinical efficacy the inclusion of those patients who had control visits at a mean follow-up of 25 days. Lucia Pacifico, M.D. Claudio Chiesa, M.D. Institute of Pediatrics; La Sapienza University of Rome; Institute of Experimental Medicine CNR; Rome, Italy