Does sub-culturing of positive MRSA blood cultures affect vancomycin MICs?
| Autor: | Akiko Kanayama Katsuse, Ritsuko Shishido, Izumo Kanesaka, Shingo Fujisaki, Makoto Nagashima, Hiroshi Takahashi, Intetsu Kobayashi, Takamitsu Ito |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Microbiology (medical) Methicillin-Resistant Staphylococcus aureus Susceptibility testing 030106 microbiology Bacteremia Microbial Sensitivity Tests medicine.disease_cause Microbiology Treatment failure Agar dilution 03 medical and health sciences Minimum inhibitory concentration 0302 clinical medicine Vancomycin medicine Animals Humans Blood culture 030212 general & internal medicine Sheep medicine.diagnostic_test business.industry General Medicine Staphylococcal Infections Anti-Bacterial Agents Staphylococcus aureus Blood Culture Positive blood culture business psychological phenomena and processes medicine.drug |
| Zdroj: | Journal of medical microbiology. 69(8) |
| ISSN: | 1473-5644 |
| Popis: | Introduction. Empirical vancomycin (VAN) treatment failure for methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia, with significantly higher mortality, has been reported for MRSA strains with reduced VAN susceptibility. Aim. Our goal was to study the effect of sub-culture on VAN minimum inhibitory concentration (MIC) values compared to direct susceptibility of MRSA-positive blood cultures. Methodology. Using 19 MRSA-positive blood cultures and 19 seeded MRSA-positive blood cultures, we compared the VAN MICs from direct susceptibility testing of MRSA-positive blood cultures and MRSA sub-cultured from positive blood cultures. Results. In comparing direct VAN MICs from MRSA-positive blood cultures and standard agar dilution, nearly half of the MICs from agar dilution were lower, with one sample decreasing from 1.5 to 0.75 µg ml−1. Furthermore, in seeded blood cultures, 80 % or more showed lower values from standard agar dilution compared to direct VAN MICs. Conclusion. Our results reveal a trend towards lower MICs after positive blood culture isolates are sub-cultured. Some clinical failures among MRSA infections treated with VAN may result from this phenomenon. |
| Databáze: | OpenAIRE |
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