Is c diff common in clindamycin use im only taking 900mg for ten days ?

Yes: C diff is commonly caused by clindamycin use.

Not that common but: C. difficile can be found in many patient populations. The anaerobic bacterium is colonized in up to 3% of the normal population. C-difficile is acquired in apprx 20% of hospitalized pts.most of whom were treated with long term antibiotics. Clindamycin is one of the more common antibiotics associated with C-diff. Usually more symptomatic with the frail, undernourished and more severely ill.