1558. Impact of host immune status on the outcome of Streptococcus pyogenes bacteremia
Session: Poster Abstract Session: Infections in the Immunocompromised Hosts
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Background: Group A streptococcus (GAS) bloodstream infection (BSI) is the most common form of invasive GAS disease. GAS-BSI occurs across patients (pts) of all age groups and immune status. Mortality due to GAS-BSI has been associated with illicit drug use, HIV infection, diabetes mellitus and toxic shock syndrome (TSS). An increasing prevalence of GAS-BSI especially among immunocompromissed (IC) pts was recently noted at our institution. We therefore evaluated the risk factors, clinical characteristics and outcome of pts with GAS-BSI.  

Methods: The study was conducted at a 900-bed tertiary care center. Pts with GAS-BSI between 1/2007 and 3/2013 were identified using the microbiology laboratory database. Medical records of pts were retrospectively reviewed. Relevant demographic, clinical and 30-day (d) outcome data were examined. Standard definitions for invasive GAS infection (including GAS-BSI and TSS) were used. IC pts were defined as those with HIV infection or active malignancy, or had received cancer chemotherapy or prednisone (>20 mg/d x >14 d) within 3 months of GAS-BSI, or were solid organ or hematopoietic stem cell transplant recipients on immunosuppressive therapy.  

Results: 102 pts with GAS-BSI were identified, 16% were IC pts.  Skin infection (43%) was the most common source of GAS-BSI and occurred in 59% of IC pts vs. 40% of non-IC pts (p-value = 0.1526). Overall 30-d mortality was 17.7% and was significantly higher among IC pts (64.7%) vs. non-IC pts (11%) (p-value= 0.0052). Septic shock (SS) developed in 38 pts [37% (71% non-IC vs. 29% IC pts)]. IC pts with SS had significantly higher mortality (63.7%) vs. non-IC pts with SS (29.6%) (p-value= 0.0433). TSS developed in 7 pts with SS (5 non-IC pts) and was not associated increased mortality. Immunosuppression was the only risk factor associated with increased mortality among pts with GAS-BSI.

Conclusion: GAS-BSI was associated with significantly higher overall 30-d mortality in IC patients. SS occurred in a third of pts and was associated with high mortality in IC pts. Clinicians should be aware of the impact of host immune status on the outcome of GAS-BSI. Prompt recognition and early aggressive treatment are pivotal in reducing mortality associated with GAS-BSI in this population.

Marisa Miceli, MD1, Samia Arshad, MPH1, Angela Kieca2, Linoj Samuel, PhD3, Mayur Ramesh, MD1 and George Alangaden, MD4, (1)Infectious Diseases, Henry Ford Hospital, Detroit, MI, (2)Office of Quality and Saftey, Henry Ford Hospital, Detroit, MI, (3)Microbiology and Pathology, Henry Ford Hospital, Detroit, MI, (4)Infectious Diseases, Henry Ford Health System, Detroit, MI

Disclosures:

M. Miceli, None

S. Arshad, None

A. Kieca, None

L. Samuel, None

M. Ramesh, None

G. Alangaden, None

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