Influence of clindamycin, administered together with or without lactobacilli, upon intestinal ecology in rats

In order to evaluate whether lactobacilli could reduce antibiotic-related ecological disturbances of the normal intestinal microflora, rats were treated daily with either lactobacilli (Lactobacillus delbrueckii subsp. bulgaricus + Streptococcus thermophilus, 108 cfu per animal for 6 days), clindamycin (4 mg/kg for 5 days) or a combination of both. The effects upon the following microflora-associated characteristics were evaluated: mucin degradation, conversion of cholesterol to coprostanol, inactivation of tryptic activity, presence of short-chain fatty acids and absence of beta-aspartylglycine. Clindamycin markedly influenced all characteristics except beta-aspartylglycine, resulting in a pattern very much alike what is found in germ-free animals. No significant differences were seen between the group receiving clindamycin + lactobacilli compared to the group receiving clindamycin only, even though the lactobacilli count increased in all animals receiving lactobacilli. We conclude that clindamycin markedly influences and disturbs normal intestinal microflora-related functions and that administration of lactobacilli of the type used in this study has no positive effect on diminishing these disturbances.