Combined defibrinated human blood and antimicrobial drug activities against Enterobacter cloacae.

The combinations of 11 antimicrobial drugs and fresh human defibrinated blood were examined for potential additive effects against several isolates of Enterobacter cloacae recovered from patients with bacteremia or meningitis. Aminoglycosides (amikacin, gentamicin, netilmicin) proved most efficacious, followed by cephalosporins (lamoxactam, cefotaxime, ceftizoxime) and ureidopenicillins (mezlocillin, piperacillin). Nalidixic acid, nitrofurantoin, and cotrimoxazole yielded indifferent effects. The E. cloacae isolates displayed low virulence for outbred NMRI mice.