Accéder directement au contenu Accéder directement à la navigation
Article dans une revue

Type II topoisomerase mutations in clinical isolates of Enterobacter cloacae and other enterobacterial species harbouring the qnrA gene

Abstract : The qnr genes are transferable genes that confer low-level quinolone resistance by protection of topoisomerase. The occurrence of mutations in DNA gyrase (gyrA, gyrB) and topoisomerase IV (parC, parE) genes in strains harbouring qnr was investigated in 28 qnrA-positive clinical isolates, among which 7 strains also harboured qnrS. Topoisomerase mutations were found in 25 (89%) of the 28 strains, with at least two mutations (gyrA and parC) in 13 strains and one mutation in 12 strains. Isolates of the Enterobacter cloacae complex were compared with reference strains of the new Enterobacter species. gyrA mutations were found at position 83 (Ser or Thr for Ile, Tyr, Leu or Phe depending on the species), and new gyrB mutations were described (S463A, S464F). qnrA had an additive effect of a 10-fold increase in the minimum inhibitory concentration (MIC) whatever the number of topoisomerase mutations, and qnrS was additive to qnrA with a further 2- to 10-fold increase in the MIC. Comparison of MICs with susceptibility breakpoints showed that strains combining qnrA and topoisomerase mutations were resistant to fluoroquinolones, but the three strains lacking a topoisomerase mutation were susceptible using ciprofloxacin and levofloxacin but not using nalidixic acid or moxifloxacin testing.
Liste complète des métadonnées

https://hal-unilim.archives-ouvertes.fr/hal-00409062
Contributeur : Ingrid Bucek <>
Soumis le : mercredi 5 août 2009 - 12:20:41
Dernière modification le : vendredi 29 mai 2020 - 14:50:04

Identifiants

Collections

Citation

Christine Lascols, Jérôme Robert, Vincent Cattoir, Cécile Bébéar, Jean-Didier Cavallo, et al.. Type II topoisomerase mutations in clinical isolates of Enterobacter cloacae and other enterobacterial species harbouring the qnrA gene. International Journal of Antimicrobial Agents, Elsevier, 2007, 29 (4), pp.402-409. ⟨10.1016/j.ijantimicag.2006.11.008⟩. ⟨hal-00409062⟩

Partager

Métriques

Consultations de la notice

133