Effect of Oral Cefotiam Hexetil (SCE2174) on Faecal Bacteria in Human Volunteers

The activity oforal cefotiam hexetil in the intestinal flora was tested in six volunteers who took 200 mg of the drug twice daily for 5 d. In all six, faecal cefotiam concentrations were below the level of detection (3 μg/g) both during and after cessation of therapy. However, using a chromogenic assay with nitrocefin, we detected beta-lactamase activity in the faeces of all the volunteers either before or during treatment. Total counts of anaerobes were not affected by cefotiam ( 10.4 ± 0.4 versus 10.4 ± 0.3 log 10 c.f.u./g faeces). In all, 1158 strains were isolated from the predominant anaerobic flora of thc volunteers, 395 before treatment, 374 during treatment and 389 after treatment, and were classified according to a simple morphological and physiological scheme. Among these isolates, the mean percentages of Gram-positive bacilli without visible spores were significantly changed by the treatment, whereas those of Gram-positive spore-forming bacilli, Gram-negative bacilli, and Gram-positive cocci were not modified. The susceptibility to cefotiam of faecal bacteria of the volunteers changed little (generally two-fold) during treatment. The mean counts of enterococci were 7.9 ± 1.4 log 10 c.f.u./g faeces before treatment and did not change significantly during treatment. The mean counts of Enterobacteriaceae dropped from 8.3 ± 0.6 to 6.6 ± 2.1 log 10 c.f.u./g during treatment. No overgrowth of staphylococci or fungi occurred. Oral treatment with cefotiam hexetil therefore appeared to have a limited impact on the composition of the faecal microflora of the volunteers, possibly because of the presence of faecal beta-lactamase activity in all of them. Keywords: Cefotiam hexetil; Faecal flora; β-lactamase.