Molecular epidemiology of bacterial infections: examples of methodology and of investigations of outbreaks.

Plasmid profile analysis, plasmid and chromosomal bacterial restriction endonuclease DNA analysis, and DNA hybridization are increasingly used in clinical microbiology and epidemiology. These techniques have been applied, singly and in combination, to investigations of outbreaks, including those of diarrheal diseases caused by pandemic Vibrio cholerae, enterotoxigenic and enterohemorrhagic Escherichia coli, Salmonella muenchen, and Salmonella typhimurium. The techniques have been critical in the unraveling of outbreaks of disease caused by nosocomial and community-acquired pathogens. Although there are limitations to these methods, their applications have important ramifications for basic science and public health.