Staphylococcus aureus bacteremia in immunosuppressed patients: a multicenter, retrospective cohort study
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Staphylococcus aureus bacteremia (SAB) causes significant morbidity and mortality. We assessed the disease severity and clinical outcomes of SAB in patients with pre-existing immunosuppression, compared with immunocompetent patients. A retrospective cohort investigation studied consecutive patients with SAB hospitalized across six hospitals in Toronto, Canada from 2007 to 2010. Patients were divided into immunosuppressed (IS) and immunocompetent (IC) cohorts; the IS cohort was subdivided into presence of one and two or more immunosuppressive conditions. Clinical parameters were compared between cohorts and between IS subgroups. A competing risk model compared in-hospital mortality and time to discharge. A total of 907 patients were included, 716 (79%) were IC and 191 (21%) were IS. Within the IS cohort, 111 (58%) had one immunosuppressive condition and 80 (42%) had two or more conditions. The overall in-hospital mortality was 29%, with no differences between groups (IS 32%, IC 28%, p = 0.4211). There were no differences in in-hospital mortality (sub-distribution hazard ratio [sHR] 1.17, 95% confidence interval [CI] 0.88–1.56, p = 0.2827) or time to discharge (sHR 0.94, 95% CI 0.78–1.15, p = 0.5570). Independent mortality predictors for both cohorts included hypotension at 72 h (IS: p < 0.0001, IC: p < 0.0001) and early embolic stroke (IS: p < 0.0001, IC: p = 0.0272). Congestive heart failure was a mortality predictor in the IS cohort (p = 0.0089). Fever within 24 h (p = 0.0092) and early skin and soft tissue infections (p < 0.0001) were survival predictors in the IS cohort. SAB causes significant mortality regardless of pre-existing immune status, but immunosuppressed patients do not have an elevated risk of mortality relative to immunocompetent patients.
This project was performed in collaboration with the Toronto Antimicrobial Stewardship Corridor (TASC). We are indebted to Pamilla Cheema, Bin Chen, Karol Sitarski, Bruce Tugwood, Bonnie Chi Thieu, Mei Shi, and Rochelle Liem for their assistance with the data collection and verification.
Compliance with ethical standards
This study was carried out as part of our routine work. The Sinai Health System-University Health Network Antimicrobial Stewardship Program was supported by an unrestricted educational grant from Pfizer Canada from 2010 to 2012, which partially supported the salary of a research coordinator (M. Steinberg). A Sinai Health System Department of Medicine Summer Studentship Award funded A. Bai. A. Morris receives partial salary support for his antimicrobial stewardship activities from Sinai Health System and University Health Network. A CIHR/CPSI Chair in Patient Safety and Continuity of Care supports C. Bell.
Conflict of interest
No authors had any conflicts of interest to declare.
Research Ethics Board approval was obtained at each of the participating sites.
All Research Ethics Boards approved waiver of consent due to the retrospective nature of the study.
- 1.Chang FY, MacDonald BB, Peacock JE Jr, Musher DM, Triplett P, Mylotte JM, O’Donnell A, Wagener MM, Yu VL (2003) A prospective multicenter study of Staphylococcus aureus bacteremia: incidence of endocarditis, risk factors for mortality, and clinical impact of methicillin resistance. Medicine (Baltimore) 82:322–332CrossRefGoogle Scholar
- 6.Lefort A, Panhard X, Clermont O, Woerther PL, Branger C, Mentré F, Fantin B, Wolff M, Denamur E; COLIBAFI Group (2011) Host factors and portal of entry outweigh bacterial determinants to predict the severity of Escherichia coli bacteremia. J Clin Microbiol 49(3):777–783CrossRefPubMedPubMedCentralGoogle Scholar
- 12.Bai AD, Showler A, Burry L, Steinberg M, Ricciuto DR, Fernandes T, Chiu A, Raybardhan S, Science M, Fernando E, Tomlinson G, Bell CM, Morris AM (2015) Comparative effectiveness of cefazolin versus cloxacillin as definitive antibiotic therapy for MSSA bacteraemia: results from a large multicentre cohort study. J Antimicrob Chemother 70(5):1539–1546CrossRefPubMedGoogle Scholar
- 13.Bai AD, Showler A, Burry L, Steinberg M, Ricciuto DR, Fernandes T, Chiu A, Raybardhan S, Science M, Fernando E, Tomlinson G, Bell CM, Morris AM (2015) Impact of Infectious disease consultation on quality of care, mortality, and length of stay in Staphylococcus aureus bacteremia: results from a large multicenter cohort study. Clin Infect Dis 60(10):1451–1461CrossRefPubMedGoogle Scholar
- 14.Bai AD, Burry L, Showler A, Steinberg M, Ricciuto D, Fernandes T, Chiu A, Raybardhan S, Tomlinson GA, Bell CM, Morris AM (2015) Usefulness of previous methicillin-resistant Staphylococcus aureus screening results in guiding empirical therapy for S aureus bacteremia. Can J Infect Dis Med Microbiol 26(4):201–206PubMedPubMedCentralGoogle Scholar
- 15.Showler A, Burry L, Bai AD, Steinberg M, Ricciuto DR, Fernandes T, Chiu A, Raybardhan S, Science M, Fernando E, Bell CM, Morris AM (2015) Use of transthoracic echocardiography in the management of low-risk Staphylococcus aureus bacteremia: results from a retrospective multicenter cohort study. JACC Cardiovasc Imaging 8(8):924–931CrossRefPubMedGoogle Scholar
- 16.Thampi N, Showler A, Burry L, Bai AD, Steinberg M, Ricciuto DR, Bell CM, Morris AM (2015) Multicenter study of health care cost of patients admitted to hospital with Staphylococcus aureus bacteremia: impact of length of stay and intensity of care. Am J Infect Control 43(7):739–744CrossRefPubMedGoogle Scholar
- 17.Clinical and Laboratory Standards Institute (CLSI) (2013) Performance standards for antimicrobial susceptibility testing; Twenty-third informational supplement. CLSI document M100-S23. CLSI, Wayne, PAGoogle Scholar
- 18.Friedman ND, Kaye KS, Stout JE, McGarry SA, Trivette SL, Briggs JP, Lamm W, Clark C, MacFarquhar J, Walton AL, Reller LB, Sexton DJ (2002) Health care-associated bloodstream infections in adults: a reason to change the accepted definition of community-acquired infections. Ann Intern Med 137(10):791–797CrossRefPubMedGoogle Scholar
- 20.Mermel LA, Farr BM, Sherertz RJ, Raad II, O’Grady N, Harris JS, Craven DE; Infectious Diseases Society of America; American College of Critical Care Medicine; Society for Healthcare Epidemiology of America (2001) Guidelines for the management of intravascular catheter-related infections. Clin Infect Dis 32(9):1249–1272CrossRefPubMedGoogle Scholar
- 21.Mermel LA, Allon M, Bouza E, Craven DE, Flynn P, O’Grady NP, Raad II, Rijnders BJ, Sherertz RJ, Warren DK (2009) Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection: 2009 Update by the Infectious Diseases Society of America. Clin Infect Dis 49(1):1–45CrossRefPubMedPubMedCentralGoogle Scholar
- 23.Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, Levison M, Bolger A, Cabell CH, Takahashi M, Baltimore RS, Newburger JW, Strom BL, Tani LY, Gerber M, Bonow RO, Pallasch T, Shulman ST, Rowley AH, Burns JC, Ferrieri P, Gardner T, Goff D, Durack DT; American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee; American Heart Association Council on Cardiovascular Disease in the Young; American Heart Association Council on Clinical Cardiology; American Heart Association Council on Cardiovascular Surgery and Anesthesia; Quality of Care and Outcomes Research Interdisciplinary Working Group (2007) Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation 116(15):1736–1754CrossRefPubMedGoogle Scholar
- 24.Fowler VG Jr, Sanders LL, Sexton DJ, Kong L, Marr KA, Gopal AK, Gottlieb G, McClelland RS, Corey GR (1998) Outcome of Staphylococcus aureus bacteremia according to compliance with recommendations of infectious diseases specialists: experience with 244 patients. Clin Infect Dis 27(3):478–486CrossRefPubMedGoogle Scholar
- 30.Hill PC, Birch M, Chambers S, Drinkovic D, Ellis-Pegler RB, Everts R, Murdoch D, Pottumarthy S, Roberts SA, Swager C, Taylor SL, Thomas MG, Wong CG, Morris AJ (2001) Prospective study of 424 cases of Staphylococcus aureus bacteraemia: determination of factors affecting incidence and mortality. Intern Med J 31(2):97–103CrossRefPubMedGoogle Scholar