Monday, November 21, 2011

Ribotyping in clincal microbiology

Ribotyping involves the fingerprinting of genomic DNA restriction fragments that contain all or part of the genes coding for the 16S and 23SrRNA. Conceptually, ribotyping is similar to probing restriction fragments of chromosomal DNA with cloned probes (randomly cloned probes or probes derived from a specific coding sequence such as that of a virulence factor).
Ribotyping assays have been used to differentiate bacterial strains in different serotypes and to determine the serotype(s)most frequently involved in outbreaks . This technique is especially useful in epidemiological studies for organisms with multiple ribosomal operons, such as members of the family of Enterobacteriaceae. Ribotyping simplifies the microrestriction patterns by rendering visible only the DNA fragments containing part or all of the ribosomal genes. The technique is less helpful when the bacterial species under investigation contains only one or a few ribosomal operons. In these instances, ribotyping typically detects only one or two bands, which limits its utility for epidemiological studies. Most studies have indicated that PFGE is superior to ribotyping for analysis of common nosocomial pathogens.

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