| Autor: |
Kok, Eric Y., Vallejo, Jesus G., Sommer, Lauren M., Rosas, Louie, Kaplan, Sheldon L., Hulten, Kristina G., McNeil, J. Chase |
| Zdroj: |
Antimicrobial Agents and Chemotherapy; February 2018, Vol. 62 Issue: 5 |
| Abstrakt: |
ABSTRACTStrains of methicillin-resistant Staphylococcus aureus(MRSA), particularly those belonging to the USA300 pulsotype, have been well described to cause severe osteoarticular infections (OAIs). A vancomycin MIC of ≥1.5 μg/ml has been demonstrated to contribute to disease severity in adults with MRSA and even methicillin-susceptible S. aureus(MSSA) bacteremia. Little data exist describing the outcomes of MSSA OAIs in terms of molecular characteristics and vancomycin MIC. All patients/isolates were chosen from a surveillance study at Texas Children's Hospital (TCH). S. aureusOAI isolates were identified from 2011 to 2016 and subjected to vancomycin Etests, pulsed-field gel electrophoresis (PFGE), and PCR to determine Panton-Valentine leucocidin (PVL) production and agrgroup. Two hundred fifty-two cases of S. aureusOAI were identified; 183 cases were MSSA (72.6%). During the study period, a decrease in the proportion of cases secondary to MRSA was observed, declining from 37.8% to 15.9% (P= 0.02). Of the MSSA isolates, 26.2% and 23.5% were USA300 and PVL positive, respectively. An increase in the proportion of MSSA isolates with a vancomycin MIC of ≥1.5 μg/ml occurred in the study period (P= 0.004). In MSSA, an elevated vancomycin MIC was associated with multiple surgical procedures and venous thromboses, even when adjusting for empirical β-lactam use. An increase in vancomycin MIC was noted among isolates belonging to agrgroup 4 during the study period. Methicillin resistance is declining among S. aureusOAI isolates at TCH. Simultaneously, vancomycin Etest MICs are increasing among MSSA isolates. Vancomycin MICs of ≥2 μg/ml are associated with adverse clinical outcomes in MSSA irrespective of antibiotic choice, suggesting that this may be a surrogate for organism virulence. |
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