Ineffectiveness of cephalexin in treatment of cephalexin-resistant bacteriuria in patients with chronic indwelling urethral catheters.

Abstract

Catheterized patients not only are subject to risks of bacteriuria but the catheter also may act as reservoirs for nosocomial infections. Antibiotics that are concentrated in the urine, even those to which the organisms are nominally resistant, have been advocated as a means of treatment and infection control. During a randomized study of repetitive 10-day courses of cephalexin in chronically catheterized patients we observed the impact of such treatment upon susceptible, moderately resistant and highly resistant strains of bacteria. Cephalexin diminished the persistence of cephalexin-susceptible strains. However, its effect upon moderately resistant (inhibited by 200 micrograms per ml.) was not different than its effect upon highly resistant (not inhibited by 200 micrograms per ml.) strains. Indeed, the persistence of strains of moderately and highly resistant organisms during cephalexin courses was similar to that of such organisms during comparable periods in patients not receiving cephalexin. The administration of cephalexin to chronically catheterized patients with moderately or highly resistant organisms causing bacteriuria does not clear these organisms from the urine.