478. Vancomycin MICs, Heteroresistance, Clinical Features and Mortality for Hospitalized Patients with Persistent and Non-Persistent MRSA Bacteremia
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: Methicillin-resistant Staphylococcus aureus bacteremia (MB) has become one of the leading causes of morbidity and mortality for hospitalized patients. We were interested in examining the association between several key microbiologic characteristics of MRSA and their possible effects on the duration of bacteremia, response to vancomycin and clinical outcomes.
Methods: We conducted a retrospective study of patients with MB. Patients who were admitted to our institution from 2001 to 2008, who had at least 1 episode of MB were divided into 2 groups, 1) patients with persistent MB (pMB) lasting ≥5 days, and 2) another cohort with non-persistent MB (npMB) of <5d duration. Vancomycin MICs (vMIC) using E-tests were performed on all the isolates, and a standardized data collection form was used to compile data that included baseline demographics, comorbid conditions, vancomycin levels, echocardiography, presence of central venous catheters (CVC), use of additional therapy, length of stay and mortality. Glycopeptide heteroresistance (GHR) screening was performed on the pMB isolates using GRD strips.
Results: There were 32 patients with pMB and 64 npMB. Baseline characteristics for both groups were similar. Vancomycin was the only agent used in 28% of the pMB group vs. 33% in the npMB group. Other features are listed in the table below:
Clinical Features for Persistent and Nonpersistent MRSA Bacteremia
Persistent(n=32)Non-persistent(n=64)
Age (y)74.570.1
Sex male (%)6056.3
Ave. duration of bacteremia (d)13.97 1.7
CVC present (%)5043.7
Use of other antimicrobials (%)71.8 Frederick Abrokwah, MD, Hospital of St. Raphael, New Haven, CT, John M. Boyce, MD, FIDSA, Medicine, Hospital of St. Raphael, New Haven, CT, Nancy L. Havill, MT(ASCP), CIC, Michael Virata, MD, Hospital of Saint Raphael, New Haven, CT and  M. D. Virata,
GlaxoSmithKline Role(s): Speaker's Bureau, Received: Speaker Honorarium.
F. Abrokwah, None..
N. L. Havill, None. 
J. M. Boyce,
Becton Dickinson Role(s): Grant Investigator, Speaker's Bureau, Grant Investigator, Speaker's Bureau, Received: Research Grant, Speaker Honorarium.
Becton Dickinson GeneOhm Role(s): Grant Investigator, Speaker's Bureau, Grant Investigator, Speaker's Bureau, Received: Research Grant, Speaker Honorarium.
3M Corporation Role(s): Consultant, Grant Investigator, Consultant, Grant Investigator, Received: Grant Recipient, Consulting Fee.
Disclosures:

F. Abrokwah, None

J. M. Boyce, None

N. L. Havill, None

M. Virata, None