Enterococcal superinfection and colonization with aztreonam therapy.

Patients were given aztreonam (SQ 26,776) parenterally for the treatment of various gram-negative infections. During or shortly after therapy, 8 (17.8%) of 45 patients became infected with or colonized by enterococcus. These eight cases included eight urinary tract isolates; one of these cases subsequently developed bacteremia. Five patients required further antimicrobial therapy directed against enterococcus. Patients receiving aztreonam are at risk for the development of enterococcal superinfection or colonization.