| Autor: |
Koreen, Larry, Ramaswamy, Srinivas V., Naidich, Steven, Koreen, Irina V., Graff, Gavin R., Graviss, Edward A., Kreiswirth, Barry N. |
| Zdroj: |
Journal of Clinical Microbiology; August 2005, Vol. 43 Issue: 8 p3985-3994, 10p |
| Abstrakt: |
ABSTRACTMolecular techniques such as spatyping and multilocus sequence typing use DNA sequence data for differentiating Staphylococcus aureusisolates. Although spatyping is capable of detecting both genetic micro- and macrovariation, it has less discriminatory power than the more labor-intensive pulsed-field gel electrophoresis (PFGE) and costly genomic DNA microarray analyses. This limitation hinders strain interrogation for newly emerging clones and outbreak investigations in hospital or community settings where robust clones are endemic. To overcome this constraint, we developed a typing system using DNA sequence analysis of the serine-aspartate (SD) repeat-encoding region within the gene encoding the keratin- and fibrinogen-binding clumping factor B (clfBtyping) and tested whether it is capable of discriminating within clonal groups. We analyzed 116 S. aureusstrains, and the repeat region was present in all isolates, varying in sequence and in length from 420 to 804 bp. In a sample of 36 well-characterized genetically diverse isolates, clfBtyping subdivided identical spaand PFGE clusters which had been discriminated by whole-genome DNA microarray mapping. The combination of spatyping and clfBtyping resulted in a discriminatory power (99.5%) substantially higher than that of spatyping alone and closely approached that of the whole-genome microarray (100.0%). clfBtyping also successfully resolved genetic differences among isolates differentiated by PFGE that had been collected over short periods of time from single hospitals and that belonged to the most prevalent S. aureusclone in the United States. clfBtyping demonstrated in vivo, in vitro, and interpatient transmission stability yet revealed that this locus may be recombinogenic in a primarily clonal population structure. Taken together, these data show that the SD repeat-encoding region of clfBis a highly stable marker of microvariation, that in conjunction with spatyping it may serve as a DNA sequence-based alternative to PFGE for investigating genetically similar strains, and that it is useful for analyzing collections of isolates in both long-term population-based and local epidemiologic studies. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
