Prolonged impact of a one-week course of clindamycin on Enterococcus spp. in human normal microbiota.

Human intestinal Enterococcus spp. was monitored during a 2-y period after 7 d clindamycin treatment. Consecutive faecal samples were collected from 8 healthy volunteers, 4 of whom had received clindamycin. After treatment, the number of enterococcal colonies was diminished and species variation extended. Erythromycin and clindamycin resistance increased from 19% to 69% and 0% to 67%, respectively. Elevated resistance levels lasted up to 9 months and erm(B) was detected in samples up to 6 months. Our results show that the clindamycin treatment had a prolonged impact on resistance and species variation.