Incidence of multi-resistant gram-negative isolates in eight Dutch hospitals. The 1990 Dutch Surveillance Study.

Results from 8 Dutch hospitals participating in an international epidemiological surveillance project were analyzed to establish the prevalence of resistant Gram-negative species and to demonstrate the extent of cross-resistance. Overall resistance rates among the 828 isolates tested were lowest with imipenem, ciprofloxacin, amikacin, and tobramycin. Pseudomonas aeruginosa isolates exhibited a significant rate of resistance to broad-spectrum beta-lactam antibiotics. Among inducible enteric species, cross-resistance to cephalosporins, penicillins, and monobactams but not to imipenem was prevalent. The addition of clavulanic acid was not found to fully restore the susceptibility of beta-lactam-resistant Escherichia coli isolates and combined cephalosporin and penicillin resistance was also observed in these strains. These data indicated a high though unevenly distributed incidence of resistance and cross-resistance among Gram-negative isolates despite the conservative approach to antibiotic treatment traditionally followed in The Netherlands.