In vitro emergence of rifampicin resistance in Propionibacterium acnes and molecular characterization of mutations in the rpoB gene.

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Serval ID
serval:BIB_C75B483555FA
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
In vitro emergence of rifampicin resistance in Propionibacterium acnes and molecular characterization of mutations in the rpoB gene.
Journal
Journal of Antimicrobial Chemotherapy
Author(s)
Furustrand Tafin U., Trampuz A., Corvec S.
ISSN
1460-2091 (Electronic)
ISSN-L
0305-7453
Publication state
Published
Issued date
2013
Volume
68
Number
3
Pages
523-528
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov'tPublication Status: ppublish
Abstract
OBJECTIVES: Activity of rifampicin against Propionibacterium acnes biofilms was recently demonstrated, but rifampicin resistance has not yet been described in this organism. We investigated the in vitro emergence of rifampicin resistance in P. acnes and characterized its molecular background.
METHODS: P. acnes ATCC 11827 was used (MIC 0.007 mg/L). The mutation rate was determined by inoculation of 10(9) cfu of P. acnes on rifampicin-containing agar plates incubated anaerobically for 7 days. Progressive emergence of resistance was studied by serial exposure to increasing concentrations of rifampicin in 72 h cycles using a low (10(6) cfu/mL) and high (10(8) cfu/mL) inoculum. The stability of resistance was determined after three subcultures of rifampicin-resistant isolates on rifampicin-free agar. For resistant mutants, the whole rpoB gene was amplified, sequenced and compared with a P. acnes reference sequence (NC006085).
RESULTS: P. acnes growth was observed on rifampicin-containing plates with mutation rates of 2 ± 1 cfu  ×  10(-9) (4096× MIC) and 12 ± 5 cfu  ×  10(-9) (4 × MIC). High-level rifampicin resistance emerged progressively after 4 (high inoculum) and 13 (low inoculum) cycles. In rifampicin-resistant isolates, the MIC remained >32 mg/L after three subcultures. Mutations were detected in clusters I (amino acids 418-444) and II (amino acids 471-486) of the rpoB gene after sequence alignment with a Staphylococcus aureus reference sequence (CAA45512). The five following substitutions were found: His-437 → Tyr, Ser-442 → Leu, Leu-444 → Ser, Ile-483 → Val and Ser-485 → Leu.
CONCLUSION: The rifampicin MIC increased from highly susceptible to highly resistant values. The resistance remained stable and was associated with mutations in the rpoB gene. To our knowledge, this is the first report of the emergence of rifampicin resistance in P. acnes.
Pubmed
Web of science
Open Access
Yes
Create date
21/03/2013 17:34
Last modification date
25/09/2019 7:10
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