Comparative effects of moxifloxacin and clarithromycin on the normal intestinal microflora

Twelve healthy male subjects age range 24-40 y participated in the investig ation, The trial was divided into 2 35-d periods. The 2 treatment regimens were: (i) 1 x 400 mg moxifloxacin tablet in the morning and 1 placebo table t in the evening for 7 d; and (ii) 1 x 500 mg clarithromycin tablet in the morning and 1 x 500 mg clarithromycin tablet in the evening for 7 d, Each s ubject received firstly; 1 treatment regimen and secondly the other treatme nt regimen. The wash-out period was 6 weeks between the two treatment regim ens, Moxifloxacin caused significant decreases of enterococci and enterobac teria during the administration period while the numbers of staphylococci, streptococci, Bacillus and Candida were not affected. No impact on peptostr eptococci, lactobacilli, Veillonella, Bacteroides or fusobacteria was obser ved, while bifidobacteria and clostridia decreased during moxifloxacin admi nistration. The microflora was normalized after 35 d, Clarithromycin caused significant reduction of Escherichia coli while the numbers of enterococci , Enterobacter, Citrobacter, Klebsiella and Pseudomonas increased markedly. No significant changes in the numbers of staphylococci, streptococci, Baci llus and Candida mere noticed, In the anaerobic microflora bifidobacteria, lactobacilli and clostridia were suppressed, while no changes in peptostrep tococci, Veillonella, Bacteroides and fusobacteria were found. The microflo ra was normalized in all volunteers after 35 d.