| Autor: |
Kenny, George E., Young, Patrick A., Cartwright, Frank D., Sjöström, Karen E., Huang, Wai M. |
| Zdroj: |
Antimicrobial Agents and Chemotherapy; October 1999, Vol. 43 Issue: 10 p2493-2496, 4p |
| Abstrakt: |
ABSTRACTThe role of mutations in the genes for GyrA and ParC in quinolone resistance in Mycoplasma hominiswas studied. Selection with sparfloxacin gave mutations at GyrA83 (Ser→Leu;Escherichia colinumbering) or GyrA87 (Glu→Lys), and mutants had increased levels of resistance to sparfloxacin (8- to 16-fold) but not to ofloxacin. Selection with ofloxacin gave changes at ParC80 (Ser→Ile) or ParC84 (Glu→Lys), and mutants were four- to eightfold more resistant to ofloxacin but not to sparfloxacin. Selection of second-step mutants from strains with ParC mutations with either quinolone yielded double mutants with additional mutations at GyrA83 (Ser→Trp or Ser→Leu) or GyrA87 (Glu→Lys). Second-step selection of GyrA mutants gave additional mutations at ParC80 (Ser→Ile) or ParC84 (Glu→Lys). Two-step mutants showed high levels of resistance to ofloxacin (MICs, 64 to 128 μg/ml) and moderate levels of resistance to sparfloxacin (MICs, 2 to 8 μg/ml). The primary target of ofloxacin in first-step mutants of Mycoplasma hominiswas ParC, whereas that for sparfloxacin was GyrA. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
