Molecular characterization of linezolid-resistant CoNS isolates in Japan.
J Antimicrob Chemother
; 70(3): 658-63, 2015 Mar.
Article
em En
| MEDLINE
| ID: mdl-25381168
ABSTRACT
OBJECTIVES:
Linezolid has been reported to remain active against 98% of staphylococci with resistance identified in 0.05% of Staphylococcus aureus and 1.4% of CoNS. The objective of this study was to characterize the linezolid-resistance mechanisms in the linezolid-resistant CoNS strains isolated in Japan.METHODS:
Staphylococcus capitis strains exhibiting linezolid MICs >8 mg/L isolated from inpatients between 2012 and 2014 were screened for cfr and mutations in 23S rRNA, L3 and L4 by PCR/sequencing. Isolates were also examined for mutations in the rlmN gene.RESULTS:
S. capitis had six 23S rRNA alleles. Five S. capitis isolates displayed linezolid MICs of 8, 16 and 32 mg/L. G2576U mutations were detected in three, four or five copies of 23S rRNA in all isolates. In two isolates exhibiting the highest linezolid MIC (32 mg/L) there was a large deletion in a single copy of 23S rRNA. Repeated 10 bp sequences were found in both 16S and 23S rRNAs, suggesting deletion by recombination between the repeats. One isolate had the mutation Ala-142âThr in the ribosomal protein L3. All linezolid-resistant isolates also demonstrated mutations in the gene encoding RlmN methyltransferase, leading to Thr-62âMet and Gly-148âSer.CONCLUSIONS:
Multiple mechanisms appeared to be responsible for the elevated linezolid resistance in S. capitis isolates a G2576U mutation in different numbers of copies of 23S rRNA, loss of a single copy of 23S rRNA and a mutation in the ribosomal protein L3, suggesting the accumulation of independent mutational events.Palavras-chave
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Staphylococcus
/
Oxazolidinonas
/
Acetamidas
/
Antibacterianos
/
Mutação
Tipo de estudo:
Prognostic_studies
Limite:
Humans
País como assunto:
Asia
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article