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| Status |
Public on May 29, 2013 |
| Title |
Staphylococcus aureus SH1000 compared to SH1000 ΔthyA |
| Organism |
Staphylococcus aureus |
| Experiment type |
Expression profiling by array
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| Summary |
Staphylococcus aureus thymidine-dependent small-colony variants (TD-SCVs) are frequently isolated from patients with chronic S. aureus infections after long-term treatment with trimethoprim-sulfamethoxazole (TMP-SMX). In TD-SCVs, mutations of thymidylate synthase (thyA, TS), essential for DNA synthesis, occur. However, it has never been shown, that TMP-SMX is responsible for the induction and selection of TD-SCVs. Short-term exposure of TMP-SMX induced the TD-SCV phenotype morphologically as shown in transmission electron-microscopy and on the transcriptional level by qRT-PCR in wild-type S. aureus, while selection of TD-SCVs with thyA mutations occurred only rarely after long-term exposure. In reversion experiments with clinical TD-SCVs, all revertants revealed compensating mutations at the initially identified mutation site. Whole DNA microarray analysis of a thyA deletion mutant (∆thyA), which exhibited the typical TD-SCV phenotype, identified tremendous alterations compared to the wild-type. Important virulence regulators such as agr, arlRS, sarA and major virulence determinants including hla, hlb, sspA, sspB and geh were down-regulated, while genes associated with the colonization capacity like fnbA, fnbB, spa, clfB, sdrC and sdrD were up-regulated. The expression of genes involved in pyrimidine and purine metabolism as well as in nucleotide interconversion changed significantly. The ∆thyA-mutant was attenuated in virulence in both, a Caenorhabditis elegans killing model and an acute murine pneumonia model. Furthermore, competition experiments in vitro and in vivo (using a chronic pneumonia mouse model) revealed a survival and growth advantage of the ∆thyA-mutant under low thymidine conditions and TMP-SMX exposure. In conclusion, our results clearly show for the first time that TMP-SMX induces the TD-SCV phenotype after short-term exposure in S. aureus and that long-term exposure selects thyA mutations providing an advantage for TD-SCVs under specified conditions. Thus, our results help to understand the dynamic processes of induction and selection of S. aureus TD-SCVs during TMP-SMX exposure.
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| Overall design |
18 independent samples were analysed; for each isolate and time point 3 replicates were performed
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| Contributor(s) |
Kriegeskorte A, Seggewiß J, Baum C, Neumann C, Becker K, Peters G, Kahl BC |
| Citation(s) |
25073642 |
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| Submission date |
May 28, 2013 |
| Last update date |
Aug 01, 2014 |
| Contact name |
Jochen Seggewiss |
| Organization name |
University of Muenster
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| Department |
Integrated Functional Genomics
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| Lab |
Genomics
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| Street address |
Roentgenstr. 21
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| City |
Muenster |
| ZIP/Postal code |
48149 |
| Country |
Germany |
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| Platforms (1) |
| GPL1339 |
[S_aureus] Affymetrix S. aureus Genome Array |
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| Samples (18)
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| Relations |
| BioProject |
PRJNA205494 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE47406_RAW.tar |
23.4 Mb |
(http)(custom) |
TAR (of CEL) |
| Processed data included within Sample table |
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