Assessment of pathogen occurrences and resistance profiles among infected patients in the intensive care unit: report from the SENTRY Antimicrobial Surveillance Program (North America, 2001).

Originating from 25 selected intensive care units (ICUs) in North America, a total of 1,321 bacterial strains from blood, respiratory tract, urine and wound sites were processed at a central laboratory as part of the SENTRY Antimicrobial Surveillance Program (2001) to assess their occurrence rates and antimicrobial susceptibility profiles. The rank order of pathogens recovered was Staphylococcus aureus (24.1%), Pseudomonas aeruginosa (12.2%), Escherichia coli (10.1%), Klebsiella spp. (8.9%), Enterococcus spp. (7.2%), coagulase-negative staphylococci (7.0%) and Enterobacter spp. (7.0%). Although oxacillin resistance among S. aureus was 51.4%, no resistance was detected to vancomycin, linezolid and quinupristin/dalfopristin. The most active agents tested against P. aeruginosa were amikacin, cefepime, tobramycin, meropenem and piperacillin/tazobactam (3.1-13.0% resistance). Among agents tested against the Enterobacteriaceae, amikacin, cefepime, imipenem and meropenem showed greatest in vitro activity (0.0-3.4% resistance). Extended-spectrum beta-lactamase-producing phenotype rates were 11.2 and 16.2% in E. coli and Klebsiella spp., respectively. Linezolid was most active against enterococci (1.1% resistance; G2576U ribosomal mutation) whereas 28.4% of isolates were resistant to vancomycin. Cefepime and the carbapenems (imipenem or meropenem) for Gram-negative isolates and linezolid for Gram-positive isolates, provided the broadest spectrum of in vitro activity against contemporary ICU pathogens in North America.