HOSPITAL-ACQUIRED INFECTIONS - DISEASES WITH INCREASINGLY LIMITED THERAPIES

About 5% of patients admitted to acute-care hospitals acquire nosocomi al infections. A variety of factors contribute: increasing age of pati ents; availability, for treatment of formerly untreatable diseases, of extensive surgical and intensive medical therapies; and frequent use of antimicrobial drugs capable of selecting a resistant microbial flor a. Nosocomial infections due to resistant organisms have been a proble m ever since infections due to penicillinase-producing Staphylococcus aureus were noted within a few years of the introduction of penicillin . By the 1960s aerobic Gram-negative bacilli had assumed increasing im portance as nosocomial pathogens, and many strains were resistant to a vailable antimicrobials. During the 1980s the principal organisms caus ing nosocomial bloodstream infections were coagulase-negative staphylo cocci, aerobic Gram-negative bacilli, S. aureus, Candida spp., and Ent erococcus spp. Coagulase-negative staphylococci and S. aureus are ofte n methicillin-resistant, requiring parenteral use of vancomycin. Preva lence of vancomycin resistance among enterococcal isolates from patien ts in intensive care units has increased, likely due to increased use of this drug. Plasmid-mediated gentamicin resistance in up to 50% of e nterococcal isolates, along with enhanced penicillin resistance in som e strains, leaves few therapeutic options. The emergence of Enterobact eriaceae with chromosomal or plasmid-encoded extended spectrum beta-la ctamases presents a world-wide problem of resistance to third generati on cephalosporins. Control of these infections rests on (1) monitoring infections with such resistant organisms in an ongoing fashion, (ii) prompt institution of barrier precautions when infected or colonized p atients are identified, and (iii) appropriate use of antimicrobials th rough implementation of antibiotic control programs.