Infections due to endemic, multiply resistant gram-negative rods: sensitivity to and therapy with cefoxitin.

A nosocomial outbreak of infections due to bacteria resistant to multiple antibiotics evolved into an endemic prevalence of several antibiotic-resistant gram-negative rods. The resistance of these bacteria to available beta-lactam antibiotics, a variety of broad-spectrum agents, and available aminoglycosides other than amikacin led to an evaluation of cefoxitin, a beta-lactamase-resistant cephamycin. Most multiply resistant isolates of Klebsiella pneumoniae, Serratia marcescens, and Proteus mirabilis were sensitive to cefoxitin in vitro. Cefoxitin therapy of 11 severe nosocomial infections caused by multiply resistant K. pneumoniae resulted in clinical and bacteriologic cure in seven patients.