Alterations in the GyrA and GyrB Subunits of topoisomerase II and the ParC and ParE subunits of topoisomerase IV in ciprofloxacin-resistant clinical isolates of Pseudomonas aeruginosa

摘要

The presence of fluoroquinolone resistance-associated alterations in topoisomerase II and IV were investigated for 103 nfxC-like type Pseudomonas aeruginosa isolates. The most nfxC-like type isolates (98.1%) possessed the substitution of Ile for Thr-83 in GyrA. A single alteration in GyrA (Thr-83 -> Ile) was the most frequently detected and the next common alteration was two alterations with Thr-83 -> Ile in GyrA and Ser-87 -> Len in ParC. A novel alteration at position Glin-106 of GyrA, which was suggested to be responsible for fluoroquinolone resistance, was identified. Our study revealed that the alterations in GyrB (Glu-468 -> Asp) and in ParE (Asp-419 -> Asn or Glu-459 -> Asp) play a complementary role in the acquisition of resistance to fluoroquinolone. There was a correlation between the ciprofloxacin MIC and the number of resistance-associated alterations in GyrA, GyrB, ParC and ParE of P. aeruginosa isolates. (C) 2005 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.