Unusual nosocomial pathogens.

Abstract

Multiple factors, including the widespread use of antibiotics, the spread of bacterial resistance plasmids and transposons, and the increased use of invasive procedures in traumatized or immunocompromised patients, have abetted the emergence of constant changes in the nosocomial microflora with selection for highly resistant and virulent bacteria. The introduction of new technologies, including enhanced life support techniques ranging from blood products to parenteral nutrient supplementation, also afford opportunities for previously nonpathogenic organisms to take advantage of new niches. Changes in the inanimate environment, such as ventilatory systems, and changes in personnel and infection control protocols (for example, disinfectants) may also alter the resident nosocomial flora. The resultant challenges to clinicians are to be aware of changes in the prevalence of different organisms and susceptibility patterns in the local hospital and community, and to be knowledgeable about new anti-microbial agents that have activity against multiply resistant pathogens. Judicious antibiotic use and careful application of hospital infection control measures are likely to be effective in meeting these challenges. Ongoing clinical and molecular epidemiological studies are required to better anticipate the emergency and spread of new, distinctive nosocomial pathogens.