Distribution of spontaneous gyrA mutations in 97 fluoroquinolone-resistant Helicobacter pylori isolates collected in France.

ABSTRACT

We determined the prevalence of gyrA mutations conferring fluoroquinolone resistance in 97 Helicobacter pylori isolates collected in France from 2007 to 2010. Ninety-four harbored one or two mutations already found in the quinolone resistance determining region (QRDR) of gyrA (for T87I, n = 23; for N87K, n = 32; for D91N, n = 30; for D91G, n = 7; for D91Y, n = 6), 2 harbored a mutation never previously described (D91H and A88P), and one strain was resistant (ciprofloxacin MIC of 8 mg/liter) without a detected mutation conferring this resistance in gyrA or gyrB genes.