Vancomycin AUC24 /MIC Ratio in Patients with Methicillin-Resistant Staphylococcus aureus Pneumonia.
BACKGROUND
Vancomycin is the treatment of choice for serious methicillin-resistant Staphylococcus aureus (MRSA) infections. The area under the concentration-time curve from 0 to 24 hr (AUC24 )/minimum inhibitory concentration (MIC) ratio was recently introduced as a parameter for assessing clinical outcome by S. aureus. This study was purposed to apply the vancomycin AUC24 /MIC in patients with MRSA pneumonia.


METHODS
Forty-seven patients with confirmed lower respiratory infection caused by MRSA during 2011 were enrolled. All patients were treated with vancomycin. Clinical characteristics and laboratory data were collected. AUC24 /MIC values were calculated as previously reported and patients were divided into two groups based on the bacteriologic response, which was eradicated or not, and an AUC24 /MIC value (above or below 400).


RESULTS
MRSA infections were eradicated in 39 patients but 8 patients had persistent MSRA infection in the following cultures. The mean AUC24 /MIC values and vancomycin concentrations were not statistically different between patients with and without MRSA eradication. All 13 patients with a vancomycin MIC of 2 mg/L had an AUC24 /MIC below 400.


CONCLUSIONS
AUC24 /MIC might not be a reliable indicator for assessing treatment response of vancomycin in MRSA pneumonia. Relationship between vancomycin AUC24 /MIC and therapeutic outcome needs to undergo further studies, including sufficiently large sample size.
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
Misuk
M
Ji
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
Hyun-Ki
HK
Kim
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
Soo-Kyung
SK
Kim
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
Woochang
W
Lee
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
Heungsup
H
Sung
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea. sailchun@amc.seoul.kr.
Sail
S
Chun
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
Mi-Na
MN
Kim
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
Won-Ki
WK
Min
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000097:blood / Q000627:therapeutic use*; D019540:Area Under Curve; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D008297:Male; D008712:Methicillin / Q000009:adverse effects; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014640:Vancomycin / Q000097:blood / Q000627:therapeutic use*; D055815:Young Adult
D000900:Anti-Bacterial Agents; D014640:Vancomycin; D008712:Methicillin
AUC24/MIC; MRSA; trough concentration; vancomycin