Molecular analysis of nosocomial epidemics.

Newer developments in molecular biology offer the hospital epidemiologist and clinical microbiologist powerful tools for analysis of nosocomial epidemics. Plasmid fingerprinting and genomic REA are rapid and often more definitive alternatives to serotyping and biotyping. Isolation of specific plasmids for special study involves more complicated manipulations. Polypeptide patterns, though at times diffuse in appearance, can be easily produced with SDS-PAGE of whole cells or outer membranes. Specific monoclonal antibodies as probes for individual proteins can generate more definitive answers about the exact type of protein(s) present. Multilocus enzyme electrophoresis (MLE) has become an ingenious tool for characterizing closely related nosocomial bacterial strains. The newest molecular methods using ribotyping, DNA probes, and the PCR will open many doors into the microbial genomes that were previously closed to the hospital microbial detective. These advances will compel hospitals to plan for their funding and implementation. Yet, like other scientific progress, the new biology in the nosocomial setting will raise as many questions as it will answer.