Article

ramR mutations in clinical isolates of Klebsiella pneumoniae with reduced susceptibility to tigecycline.

Institute of Medical Microbiology, Virology and Hygiene, University Medical Centre Hamburg-Eppendorf,Martinistrasse, Hamburg, Germany.
Antimicrobial Agents and Chemotherapy (impact factor: 4.84). 03/2010; 54(6):2720-3. DOI:10.1128/AAC.00085-10
Source: PubMed

ABSTRACT Five Klebsiella pneumoniae isolates with reduced susceptibility to tigecycline (MIC, 2 microg/ml) were analyzed. A gene homologous to ramR of Salmonella enterica was identified in Klebsiella pneumoniae. Sequencing of ramR in the nonsusceptible Klebsiella strains revealed deletions, insertions, and point mutations. Transformation of mutants with wild-type ramR genes, but not with mutant ramR genes, restored susceptibility to tigecycline and repressed overexpression of ramA and acrB. Thus, this study reveals a molecular mechanism for tigecycline resistance in Klebsiella pneumoniae.

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    International Journal of Antimicrobial Agents 01/2011; · 4.13 Impact Factor
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Keywords

2 microg/ml
 
insertions
 
Klebsiella pneumoniae
 
molecular mechanism
 
mutant ramR genes
 
mutants
 
nonsusceptible Klebsiella strains
 
ramA
 
ramR
 
Salmonella enterica
 
Sequencing
 
susceptibility
 
wild-type ramR genes
 

M Hentschke