| Autor: |
Spinaci, Cinzia, Magi, Gloria, Zampaloni, Claudia, Vitali, Luca A., Paoletti, Claudia, Catania, Maria R., Prenna, Manuela, Ferrante, Luigi, Ripa, Sandro, Varaldo, Pietro E., Facinelli, Bruna |
| Zdroj: |
Journal of Clinical Microbiology; February 2004, Vol. 42 Issue: 2 p639-644, 6p |
| Abstrakt: |
ABSTRACTThe RD2region of the internalization-associated gene prtF1, which encodes the fibronectin-binding repeat domain type 2 of protein F1, plays a crucial role in the entry of group A streptococci (GAS) into epithelial cells. A molecular study of the variability of the RD2region was carried out with 77 independent Italian GAS, 66 erythromycin resistant (ER) and 11 erythromycin susceptible (ES), which had previously been investigated for the association between erythromycin resistance and ability to enter human respiratory cells. The amplicons obtained from PCR analysis of the RD2region were consistent with a number of RD2repeats ranging from one to five, more frequently four (n= 30), three (n= 27), and one (n= 18). A new method to type cell-invasive GAS (RD2typing) was developed by combining PCR analysis of the RD2region and restriction analysis of PCR products with endonucleases HaeIII, DdeI, and HinfI. Overall, 10 RD2types (a to j) were distinguished (all detected among the 66 ER isolates, four detected among the 11 ES isolates). Comparison and correlation of RD2typing data with the genotype and phenotype of macrolide resistance and with data from PCR M typing and SmaI macrorestriction analysis allowed us to identify 41 different clones (31 among the 66 ER isolates and 10 among the 11 ES isolates). Three major clones accounted for 40% of the isolates (47% of ER strains). Some ES isolates appeared to be related to ER isolates with identical combinations of RD2type and emmtype. While simultaneous use of different typing methods is essential for a thorough investigation of GAS epidemiology, RD2typing may be especially helpful in typing cell-invasive GAS. |
| Databáze: |
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