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Volume 43, Number 6, December 2010

Clinical Characteristics and Risk Factors for Mortality in Patients with Meningitis Caused by Staphylococcus aureus and Vancomycin Minimal Inhibitory Concentrations Against These Isolates


Wen-Chi Huang, Chen-Hsiang Lee, Jien-Wei Liu


Received: April 30, 2009    Revised: June 25, 2009    Accepted: August 31, 2009   

 

Corresponding author:

Jien-Wei Liu, Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital-Kaohsiung Medical Center, 123 Ta Pei Road, Niao Sung Hsiang, Kaohsiung Hsien 833, Taiwan. E-mail: 88b0@adm.cgmh.org.tw



 

Background and purpose: 

Bacterial meningitis caused by Staphylococcus aureus is uncommon but has a high mortality rate. The aims of this study were to better understand the clinical manifestations of S. aureus meningitis, to identify the risk factors for mortality in the affected patients, and to determine the levels of vancomycin minimal inhibitory concentrations (MICs) against these pathogens.



 

Methods:

A retrospective study of patients with S. aureus meningitis hospitalized between December 2000 and December 2008 was made, and vancomycin MICs against S. aureus isolates was determined using Etest.



 

Results:

Among 37 patients with S. aureus meningitis, fever was most commonly observed. Twenty-six patients (70.3%) had received prior neurosurgery, and 24 (64.9%) patients were suffering from methicillin-
resistant S. aureus (MRSA) infections. The vancomycin MIC of 2 μg/mL was found in 23 (74.2%) of 31
S. aureus isolates available for testing. Excluding three patients who did not receive antibiotics for their
S. aureus meningitis the mortality rate was 35.3% in the 34 remaining patients, with concurrent infective
endocarditis an independent risk factor for mortality (odds ratio = 21.00; 95% confidence interval,  1.834–240.515; p = 0.01).



 

Conclusion:

Patients with S. aureus meningitis and concurrent infective endocarditis were at a higher risk of mortality. A vancomycin MIC of 2 μg/mL against a substantial number of S. aureus isolates that grew from the cerebrospinal fluid suggests the importance of obtaining trough vancomycin concentrations of 15–20 μg/mL for the treatment of MRSA meningitis.



 

Key words:

bacterial meningitis, infective endocarditis, minimal inhibitory concentration, Staphylococcus aureus, vancomycin