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Molecular basis for different levels of tet(M) expression in Streptococcus pneumoniae clinical isolates.
- Source :
-
Antimicrobial agents and chemotherapy [Antimicrob Agents Chemother] 2012 Oct; Vol. 56 (10), pp. 5040-5. Date of Electronic Publication: 2012 Jul 16. - Publication Year :
- 2012
-
Abstract
- Seventy-four unrelated clinical isolates of Streptococcus pneumoniae harboring the tet(M) gene were studied. Seven strains with low tetracycline (Tc) MICs (0.25 to 0.5 μg/ml) were found to harbor truncated tet(M) alleles that were inactivated by different frameshift mutations. In contrast, five strains bore deletions in the tet(M) promoter region, among which four displayed increased Tc MICs (16 to 64 μg/ml). The same promoter mutations were detected in Tc-resistant mutants selected in vitro from various susceptible strains. Sequence analysis revealed that these deletions might impede the formation of the transcriptional attenuator located immediately upstream of tet(M). Expression in Enterococcus faecalis of a tet(M) reporter gene transcribed from these promoter mutants conferred a level of Tc resistance similar to that observed in the parental S. pneumoniae strains. These results show that different levels of Tc susceptibility found in clinical isolates of S. pneumoniae can be explained by frameshift mutations within tet(M) and by alterations of the upstream transcriptional attenuator.
- Subjects :
- Acinetobacter drug effects
Acinetobacter metabolism
Acinetobacter ultrastructure
Alginates chemistry
Bacterial Proteins metabolism
Biofilms drug effects
Burkholderia drug effects
Burkholderia metabolism
Burkholderia ultrastructure
Glucuronic Acid chemistry
Hexuronic Acids chemistry
Microscopy, Atomic Force
Microscopy, Confocal
Oligosaccharides chemical synthesis
Oligosaccharides chemistry
Pseudomonas drug effects
Pseudomonas metabolism
Pseudomonas ultrastructure
Streptococcus pneumoniae metabolism
Streptococcus pneumoniae ultrastructure
Tetracycline Resistance
Anti-Bacterial Agents pharmacology
Oligosaccharides pharmacology
Streptococcus pneumoniae drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 1098-6596
- Volume :
- 56
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Antimicrobial agents and chemotherapy
- Publication Type :
- Academic Journal
- Accession number :
- 22802249
- Full Text :
- https://doi.org/10.1128/AAC.00939-12