Varon Emmanuelle, Houssaye Serge, Grondin Sophie, Gutmann Laurent
L.R.M.A., INSERM, U655, Université Paris 6, and Université Paris 5, 75270 Paris cedex 06, France.
Antimicrob Agents Chemother. 2006 Feb;50(2):572-9. doi: 10.1128/AAC.50.2.572-579.2006.
With respect to pneumococci, there is a need to detect first-step mutants with reduced fluoroquinolone (FQ) susceptibility from which second-step, resistant mutants are likely to be selected in the presence of antipneumococcal FQs. Here, we describe an interpretative disk diffusion test, of which three options are presented, that allows the distinction between first- and second-step mutants. Using five FQ disks (pefloxacin, norfloxacin, levofloxacin, ciprofloxacin, and sparfloxacin, option 1), all known mechanisms of altered FQ susceptibility found in first-step mutants (ParC, ParE, GyrA, or efflux) and in second-step mutants (ParC and GyrA or ParE and GyrA) can be accurately detected, making this option a useful epidemiological tool. Using three FQ disks (pefloxacin, norfloxacin, and levofloxacin, option 2), the most prevalent FQ-resistant mutants, but not the first-step GyrA mutants, can be detected. With only two FQ disks (norfloxacin and levofloxacin) in the third and simplest option, first-step mutants can be distinguished from second-step mutants, however, without differentiation of ParC, ParE, or efflux alterations.
关于肺炎球菌，有必要检测氟喹诺酮（FQ）敏感性降低的第一步突变体，在使用抗肺炎球菌FQ的情况下，可能会从中选择第二步耐药突变体。在此，我们描述了一种解释性纸片扩散试验，该试验提供了三种选择，可区分第一步和第二步突变体。使用五个FQ纸片（培氟沙星、诺氟沙星、左氧氟沙星、环丙沙星和司帕沙星，选项1），可以准确检测到在第一步突变体（ParC、ParE、GyrA或外排）和第二步突变体（ParC和GyrA或ParE和GyrA）中发现的所有已知FQ敏感性改变机制，使该选项成为一种有用的流行病学工具。使用三个FQ纸片（培氟沙星、诺氟沙星和左氧氟沙星，选项2），可以检测到最常见的FQ耐药突变体，但不能检测到第一步GyrA突变体。在第三个也是最简单的选项中，仅使用两个FQ纸片（诺氟沙星和左氧氟沙星），可以区分第一步突变体和第二步突变体，然而，无法区分ParC、ParE或外排改变。
