Oct 10, 2015 - MD4; Nitin Bhanot, MD, MPH3; 1Infectious Disease, Allegheny General ... Pittsburgh, Pennsylvania; 2Infectious Disease, Allegheny General ...
1736. Propionibacterium Acnes: Time-to-Positivity of Cultures From Different Clinical Sites Rasha Abdulmassih, MD1; Jina Makadia, MD2; Zaw Min, MD, FACP3; James Como, MD4; Nitin Bhanot, MD, MPH3; 1Infectious Disease, Allegheny General Hospital, Pittsburgh, Pennsylvania; 2Infectious Disease, Allegheny General Hospital, Pittsburgh, Pennsylvania; 3Department of Medicine, Division of Infectious Diseases, Allegheny General Hospital, Pittsburgh, Pennsylvania; 4Allegheny General Hospital, Pittsburgh, Pennsylvania Session: 242. Novel Diagnostics for Uncommon Bacteria Saturday, October 10, 2015: 12:30 PM Background. Infections from Propionibacterium acnes are generally uncommon. Reasons for this may be underestimation since this microbe is often not recovered in cultures until after 5 days, and often dismissal as a contaminant. The objectives of our quality improvement project were to (1) determine time-to-positivity (TTP) of P. acnesgrowth and (2) identify P. acnes from clinically relevant sites in suspected infections. Methods. All cultures positive for P. acnes from 2010 to 2014 were retrieved through the laboratory database. Specimen sources and TTP were recorded. Electronic chart review was conducted to see which isolates were regarded as clinically relevant.
Sites of Isolation (total: 146) Blood Central Nervous System a) Epidural tissue b) Cerebrospinal fluid from Ventriculoperitoneal shunt c) Craniotomy site d) Brain tissue e) Subdural Hematoma
N (%)
TTP(range in days)
Median(days)
26 (17.8)
4-6
5
12 (8.2) 12 (8.2)
3-7 3-7
6 5.5
29 (19.8) 1 (0.68) 1 (0.68)
3-8 7 7
6 -
continued. Sites of Isolation (total: 146)
N (%)
Musculoskeletal a) Native joints b) Prosthetic joints c) Vertebral spine tissue Skin and Soft Tissue Cardiac Device Lymph node Abdominal a) Biliary Drain b) Peritoneal Fluid Arteriovenous graft Pleural Fluid
TTP(range in days)
Median(days)
5 11 8 22 8 1
(3.4) (7.5) (5.4) (15) (5.4) (0.68)
4-7 5-6 5-8 3-11 5-10 6
5 6 7 6 7 -
2 2 1 5
(1.36) (1.36) (0.68) (3.4)
7 6 5 5-8
7 6 6
Results. A total of 146 specimens from 121 patients were analyzed. Table (below) reveals sites of isolation and TTP. Both native tissue and prosthetic (orthopedic, cardiovascular, and CNS) infections were identified. Majority of positive cultures were from CNS, blood, and musculoskeletal sites (37.5%, 17.8%, and 16.3%, respectively). The maximum TTP from CNS and musculoskeletal cultures was 8 days. Overall, TTP ranged from 3 to 11 days (mean 5.73 +/- 1.25 days, median 6 days). Majority (86%) of the isolates were mono-microbial. In 37% (54/146) of instances, antibiotics were targeted solely against P. acnes. Conclusion. While we request our laboratory to hold cultures for 2 weeks for suspected P. acnes infection, limiting extension to 11 days may be sufficient. P. acnes infections are likely more varied than generally thought. Routine implementation of longer incubation periods should be considered especially in suspected cases of infection with negative cultures at day 5. Such information has implications to inform targeted, appropriate, and maximally effective antimicrobial therapy. Disclosures. All authors: No reported disclosures.
Poster Abstracts
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OFID 2015:2 (Suppl 1)
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S447
