986. Unnecessary Antibiotic Use Among Patients with Blood Cultures Positive for Viridans Streptococci
Session: Poster Abstract Session: Antibiotic Stewardship: General Acute Care Implementation and Outcomes
Friday, October 28, 2016
Room: Poster Hall
Background: Viridans streptococci (VS) isolated from blood cultures (BC) can indicate serious conditions such as endocarditis, but may also be due to BC contamination in a significant number of cases. We aimed to determine the extent of unnecessary antibiotic use among a cohort of patients with VS isolated from BC.

Methods: All patients with VS from at least one BC bottle at a tertiary care medical center between Jan 2014 and Dec 2015 were included. True bacteremia (including endocarditis) and possibly true bacteremia were defined as per established clinical criteria and/or – for possible cases – as per the primary team’s clinical judgement; others were called contaminants. Zero time (ZT) was defined as the date of the first positive BC with VS. Information on baseline demographic, clinical, and microbiological variables was obtained through retrospective medical record review.

Results: The median age of the total cohort (n=53) was 65 (range, 24 to 93) years, 35 (66%) were male; 17 (32%) patients were located in an intensive care unit at ZT. The median Charlson score was 2. Major comorbidities included diabetes (32%), malignancy (25%), liver disease (21%), immunocompromise (15%), known cardiac valve disease (13%), and end-stage renal disease (9%). 19 (36%) patients had only one positive BC bottle; however, 49 (92%) had at least two BC sets done at ZT. The median duration of bacteremia was one day. Positive BC were considered true, possibly true, and contaminant in 23 (43%), 19 (36%), and 11 (21%) patients, respectively. Of interest, SIRS criteria were present in only 23 (43%) patients around ZT. All but two patients received antibiotics for VS from BC. Patients with true or possibly true bacteremia were treated with antibiotics for a median of 14 (range, 4 to 84) days whereas those with BC contaminants were treated for a median of 7 days (range, 1 to 10 days; P<0.001). Three (27%) among the latter were readmitted within thirty days, but none developed a complication caused by VS, Clostridium difficile, or a MDR organism.

Conclusion: Patients with VS contaminants of BC (defined as per our conservative definition) received an average of seven days of unnecessary antibiotics. Antibiotic stewardship initiatives to reduce antimicrobial usage in these patients are indicated.

Sonal Bajaj, MD1, David C. Perlman, MD1, Polina Lerner, PharmD2, Marianna Fedorenko, PharmD2, Donna Mildvan, M.D.1 and Jorg Ruhe, MD1, (1)Infectious Diseases, Mount Sinai Beth Israel, Icahn School of Medicine at Mount Sinai, New York, NY, (2)Department of Pharmacy, Mount Sinai Beth Israel, New York, NY


S. Bajaj, None

D. C. Perlman, None

P. Lerner, None

M. Fedorenko, None

D. Mildvan, None

J. Ruhe, None

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