Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-4243
Sander, P; Belova, L; Kidan, Y G; Pfister, P; Mankin, A S; Böttger, E C (2002). Ribosomal and non-ribosomal resistance to oxazolidinones: species-specific idiosyncrasy of ribosomal alterations. Molecular Microbiology, 46(5):1295-1304.
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A derivative of Mycobacterium smegmatis, which carries only one functional rRNA (rrn) operon, was used to isolate mutants resistant to the ribosome-targeted antibiotic linezolid. Isolation and characterization of linezolid-resistant clones revealed two classes of mutants. Ribosomes from class I mutants are resistant to oxazolidinones in an in vitro peptidyl transferase assay, indicating that resistance maps to the ribosome component. In contrast, ribosomes from class II mutants show wild-type susceptibility to a linezolid derivative in vitro, pointing to a non-ribosomal mechanism of resistance. Introduction of a wild-type ribosomal RNA operon into linezolid-resistant strains restored linezolid sensitivity in class I mutants, indicating that resistance (i) maps to the rRNA and (ii) is recessive. Sequencing of the entire rrn operon identified a single nucleotide alteration in 23S rRNA of class I mutant strains, 2447G --> T (Escherichia coli numbering). Introduction of mutant rrl2447T into M. smegmatis rrn- resulted in a linezolid-resistant phenotype, demonstrating a cause-effect relationship of the 2447G --> T alteration. The 2447G --> T mutation, which renders M. smegmatis linezolid resistant, confers lethality in E. coli. This finding is strong evidence of structural and pos-sibly functional differences between the ribosomes of Gram-positive and Gram-negative bacteria. In agreement with the results of the in vitro assay, class II mutants show a wild-type sequence of the complete rRNA operon. The lack of cross-resistance of the class II mutants to other antibiotics suggests a resistance mechanism other than activation of a broad-spectrum multidrug transporter.
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|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > Institute of Medical Microbiology|
|Dewey Decimal Classification:||570 Life sciences; biology
610 Medicine & health
|Deposited On:||26 Mar 2009 13:29|
|Last Modified:||02 Dec 2013 14:07|
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