[Patterns of antimicrobial resistance in gram-negative bacilli isolated from patients in intensive care units].

Minimal inhibitory concentration test with 16 antibiotics was performed for 435 stains of Gram negative bacilli, isolated from patients in intensive care units of five large hospitals. The results were analysed as to provide in vitro sensitivity patterns, as well as cross resistance between the tested drugs. The most frequent species were Pseudomonas aeruginosa, E. coli, Klebsiella spp., Enterobacter ssp., and Acinetobacter calcoaceticu, accounting for more than 80% of all isolates. Best figures were seen with ciprofloxacin and imipenem, with 805 of sensitive strains or more; third generation cephalosporins, aminoglycosides and aztreonam had overall sensitivity rates ranging from 58 to 73%. There was marked cross resistance between ceftazidime and other beta-lactam antibiotics, except for imipenem. These results bear implications regarding the establishment of empirical therapy in critical patients.