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Importance: Staphylococcus aureus bacteremia (SAB) is common and associated with poor long-term outcomes. Previous studies have demonstrated an association between infectious diseases (ID) consultation and improved short-term (ie, within 90 days) outcomes for patients with SAB, but associations with long-term outcomes are unknown., Objective: To investigate the association of ID consultation with long-term (ie, 5 years) postdischarge outcomes among patients with SAB., Design, Setting, and Participants: This cohort study included all patients (N = 31 002) with a first episode of SAB who were discharged alive from 116 acute care units of the nationwide Veterans Health Administration where ID consultation was offered. Data were collected from January 2003 to December 2014, with follow-up through September 30, 2018. Data analysis was conducted from February to December 2019., Exposures: Infectious diseases consultation during the index hospital stay., Main Outcomes and Measures: The primary outcome was time to development of a composite event of all-cause mortality or recurrence of SAB within 5 years of discharge. As secondary outcomes, SAB recurrence and all-cause mortality with and without recurrence were analyzed while accounting for semicompeting risks., Results: The cohort included 31 002 patients (30 265 [97.6%] men; median [interquartile range] age at SAB onset, 64.0 [57.0-75.0] years). Among 31 002 patients, there were 18 794 (60.6%) deaths, 4772 (15.4%) SAB recurrences, and 20 414 (65.8%) composite events during 5 years of follow-up; 12 773 deaths (68.0%) and 2268 recurrences (47.5%) occurred more than 90 days after discharge. Approximately half of patients (15 360 [49.5%]) received ID consultation during the index hospital stay; ID consultation was associated with prolonged improvement in the composite outcome (adjusted hazard ratio at 5 years, 0.71; 95% CI, 0.68-0.74; P < .001). Infectious diseases consultation was also associated with improved outcomes when all-cause mortality without recurrence and SAB recurrence were analyzed separately (all-cause mortality without recurrence: adjusted hazard ratio at 5 years, 0.77; 95% CI, 0.74-0.81; P < .001; SAB recurrence: adjusted hazard ratio at 5 years, 0.68; 95% CI, 0.64-0.72; P < .001)., Conclusions and Relevance: Having an ID consultation during the index hospital stay among patients with SAB was associated with improved postdischarge outcomes for at least 5 years, suggesting that contributions of ID specialists to management during acute infection may have a substantial influence on long-term outcomes. Further investigations of the association of ID consultation with outcomes after S aureus should include long-term follow-up.

Importance: Staphylococcus aureus bacteremia is common and frequently associated with poor outcomes. Evidence indicates that specific care processes are associated with improved outcomes for patients with S aureus bacteremia, including appropriate antibiotic prescribing, use of echocardiography to identify endocarditis, and consultation with infectious diseases (ID) specialists. Whether use of these care processes has increased in routine care for S aureus bacteremia or whether use of these processes has led to large-scale improvements in survival is unknown., Objective: To examine the association of evidence-based care processes in routine care for S aureus bacteremia with mortality., Design, Setting, and Participants: This retrospective observational cohort study examined all patients admitted to Veterans Health Administration (VHA) acute care hospitals who had a first episode of S aureus bacteremia from January 1, 2003, through December 31, 2014., Exposures: Use of appropriate antibiotic therapy, echocardiography, and ID consultation., Main Outcomes and Measures: Thirty-day all-cause mortality., Results: Analyses included 36 868 patients in 124 hospitals (mean [SD] age, 66.4 [12.5] years; 36 036 [97.7%] male), including 19 325 (52.4%) with infection due to methicillin-resistant S aureus and 17 543 (47.6%) with infection due to methicillin-susceptible S aureus. Risk-adjusted mortality decreased from 23.5% (95% CI, 23.3%-23.8%) in 2003 to 18.2% (95% CI, 17.9%-18.5%) in 2014. Rates of appropriate antibiotic prescribing increased from 2467 (66.4%) to 1991 (78.9%), echocardiography from 1256 (33.8%) to 1837 (72.8%), and ID consultation from 1390 (37.4%) to 1717 (68.0%). After adjustment for patient characteristics, cohort year, and other care processes, receipt of care processes was associated with lower mortality, with adjusted odds ratios of 0.74 (95% CI, 0.68-0.79) for appropriate antibiotics, 0.73 (95% CI, 0.68-0.78) for echocardiography, and 0.61 (95% CI, 0.56-0.65) for ID consultation. Mortality decreased progressively as the number of care processes that a patient received increased (adjusted odds ratio for all 3 processes compared with none, 0.33; 95% CI, 0.30-0.36). An estimated 57.3% (95% CI, 48.4%-69.9%) of the decrease in mortality between 2003 and 2014 could be attributed to increased use of these evidence-based care processes., Conclusions and Relevance: Mortality associated with S aureus bacteremia decreased significantly in VHA hospitals, and a substantial portion of the decreasing mortality may have been attributable to increased use of evidence-based care processes. The experience in VHA hospitals demonstrates that increasing application of these care processes may improve survival among patients with S aureus bacteremia in routine health care settings.

Background: To treat patients with methicillin-susceptible Staphylococcus aureus (MSSA) infections, β-lactams are recommended for definitive therapy; however, the comparative effectiveness of individual β-lactams is unknown. This study compared definitive therapy with cefazolin vs nafcillin or oxacillin among patients with MSSA infections complicated by bacteremia., Methods: This retrospective study included patients admitted to 119 Veterans Affairs hospitals from 2003 to 2010. Patients were included if they had a blood culture positive for MSSA and received definitive therapy with cefazolin, nafcillin, or oxacillin. Cox proportional hazards regression and ordinal logistic regression were used to identify associations between antibiotic therapy and mortality or recurrence. A recurrent infection was defined as a MSSA blood culture between 45 and 365 days after the first MSSA blood culture., Results: Of 3167 patients, 1163 (37%) patients received definitive therapy with cefazolin. Patients who received cefazolin had a 37% reduction in 30-day mortality (hazard ratio [HR], 0.63; 95% confidence interval [CI], .51-.78) and a 23% reduction in 90-day mortality (HR, 0.77; 95% CI, .66-.90) compared with patients receiving nafcillin or oxacillin, after controlling for other factors. The odds of recurrence (odds ratio, 1.13; 95% CI, .94-1.36) were similar among patients who received cefazolin compared with patients who received nafcillin or oxacillin, after controlling for other factors., Conclusions: In this large, multicenter study, patients who received cefazolin had a lower risk of mortality and similar odds of recurrent infections compared with nafcillin or oxacillin for MSSA infections complicated by bacteremia. Physicians might consider definitive therapy with cefazolin for these infections., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

We retrospectively analyzed data for 195 respiratory infection patients who had positive Staphyloccocus aureus cultures and who were hospitalized in 2 hospitals in Iowa and Maryland, USA, during 2003-2009. Odds for death for patients who also had influenza-positive test results were >4 times higher than for those who had negative influenza test results.

Importance: Previous studies suggested that a bundled intervention was associated with lower rates of Staphylococcus aureus surgical site infections (SSIs) among patients having cardiac or orthopedic operations., Objective: To evaluate whether the implementation of an evidence-based bundle is associated with a lower risk of S. aureus SSIs in patients undergoing cardiac operations or hip or knee arthroplasties., Design, Setting, and Participants: Twenty hospitals in 9 US states participated in this pragmatic study; rates of SSIs were collected for a median of 39 months (range, 39-43) during the preintervention period (March 1, 2009, to intervention) and a median of 21 months (range, 14-22) during the intervention period (from intervention start through March 31, 2014)., Interventions: Patients whose preoperative nares screens were positive for methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA) were asked to apply mupirocin intranasally twice daily for up to 5 days and to bathe daily with chlorhexidine-gluconate (CHG) for up to 5 days before their operations. MRSA carriers received vancomycin and cefazolin or cefuroxime for perioperative prophylaxis; all others received cefazolin or cefuroxime. Patients who were MRSA-negative and MSSA-negative bathed with CHG the night before and morning of their operations. Patients were treated as MRSA-positive if screening results were unknown., Main Outcomes and Measures: The primary outcome was complex (deep incisional or organ space) S. aureus SSIs. Monthly SSI counts were analyzed using Poisson regression analysis., Results: After a 3-month phase-in period, bundle adherence was 83% (39% full adherence; 44% partial adherence). Overall, 101 complex S. aureus SSIs occurred after 28,218 operations during the preintervention period and 29 occurred after 14,316 operations during the intervention period (mean rate per 10,000 operations, 36 for preintervention period vs 21 for intervention period, difference, -15 [95% CI, -35 to -2]; rate ratio [RR], 0.58 [95% CI, 0.37 to 0.92]). The rates of complex S. aureus SSIs decreased for hip or knee arthroplasties (difference per 10,000 operations, -17 [95% CI, -39 to 0]; RR, 0.48 [95% CI, 0.29 to 0.80]) and for cardiac operations (difference per 10,000 operations, -6 [95% CI, -48 to 8]; RR, 0.86 [95% CI, 0.47 to 1.57])., Conclusions and Relevance: In this multicenter study, a bundle comprising S. aureus screening, decolonization, and targeted prophylaxis was associated with a modest, statistically significant decrease in complex S. aureus SSIs.

Background: The high prevalence of methicillin-resistant S. aureus (MRSA) has led clinicians to select antibiotics that have coverage against MRSA, usually vancomycin, for empiric therapy for suspected staphylococcal infections. Clinicians often continue vancomycin started empirically even when methicillin-susceptible S. aureus (MSSA) strains are identified by culture. However, vancomycin has been associated with poor outcomes such as nephrotoxicity, persistent bacteremia and treatment failure. The objective of this study was to compare the effectiveness of vancomycin versus the beta-lactam antibiotics nafcillin and cefazolin among patients with MSSA bacteremia. The outcome of interest for this study was 30-day in-hospital mortality., Methods: This retrospective cohort study included all adult in-patients admitted to a tertiary-care facility between January 1, 2003 and June 30, 2007 who had a positive blood culture for MSSA and received nafcillin, cefazolin or vancomycin. Cox proportional hazard models were used to assess independent mortality hazards comparing nafcillin or cefazolin versus vancomycin. Similar methods were used to estimate the survival benefits of switching from vancomycin to nafcillin or cefazolin versus leaving patients on vancomycin. Each model included statistical adjustment using propensity scores which contained variables associated with an increased propensity to receive vancomycin., Results: 267 patients were included; 14% (38/267) received nafcillin or cefazolin, 51% (135/267) received both vancomycin and either nafcillin or cefazolin, and 35% (94/267) received vancomycin. Thirty (11%) died within 30 days. Those receiving nafcillin or cefazolin had 79% lower mortality hazards compared with those who received vancomycin alone (adjusted hazard ratio (HR): 0.21; 95% confidence interval (CI): 0.09, 0.47). Among the 122 patients who initially received vancomycin empirically, those who were switched to nafcillin or cefazolin (66/122) had 69% lower mortality hazards (adjusted HR: 0.31; 95% CI: 0.10, 0.95) compared to those who remained on vancomycin., Conclusions: Receipt of nafcillin or cefazolin was protective against mortality compared to vancomycin even when therapy was altered after culture results identified MSSA. Convenience of vancomycin dosing may not outweigh the potential benefits of nafcillin or cefazolin in the treatment of MSSA bacteremia.

Accessory gene regulator (agr) dysfunction in Staphylococcus aureus has been associated with a longer duration of bacteremia. We aimed to assess the independent association between agr dysfunction in S. aureus bacteremia and 30-day in-hospital mortality. This retrospective cohort study included all adult inpatients with S. aureus bacteremia admitted between 1 January 2003 and 30 June 2007. Severity of illness prior to culture collection was measured using the modified acute physiology score (APS). agr dysfunction in S. aureus was identified semiquantitatively by using a δ-hemolysin production assay. Cox proportional hazard models were used to measure the association between agr dysfunction and 30-day in-hospital mortality, statistically adjusting for patient and pathogen characteristics. Among 814 patient admissions complicated by S. aureus bacteremia, 181 (22%) patients were infected with S. aureus isolates with agr dysfunction. Overall, 18% of patients with agr dysfunction in S. aureus died, compared to 12% of those with functional agr in S. aureus (P = 0.03). There was a trend toward higher mortality among patients with S. aureus with agr dysfunction (adjusted hazard ratio [HR], 1.34; 95% confidence interval [CI], 0.87 to 2.06). Among patients with the highest APS (scores of >28), agr dysfunction in S. aureus was significantly associated with mortality (adjusted HR, 1.82; 95% CI, 1.03 to 3.21). This is the first study to demonstrate an independent association between agr dysfunction and mortality among severely ill patients. The δ-hemolysin assay examining agr function may be a simple and inexpensive approach to predicting patient outcomes and potentially optimizing antibiotic therapy.

Background: Appropriate empiric therapy, antibiotic therapy with in vitro activity to the infecting organism given prior to confirmed culture results, may improve Staphylococcus aureus outcomes. We aimed to measure the clinical impact of appropriate empiric antibiotic therapy on mortality, while statistically adjusting for comorbidities, severity of illness and presence of virulence factors in the infecting strain., Methodology: We conducted a retrospective cohort study of adult patients admitted to a tertiary-care facility from January 1, 2003 to June 30, 2007, who had S. aureus bacteremia. Time to appropriate therapy was measured from blood culture collection to the receipt of antibiotics with in vitro activity to the infecting organism. Cox proportional hazard models were used to measure the association between receipt of appropriate empiric therapy and in-hospital mortality, statistically adjusting for patient and pathogen characteristics., Principal Findings: Among 814 admissions, 537 (66%) received appropriate empiric therapy. Those who received appropriate empiric therapy had a higher hazard of 30-day in-hospital mortality (Hazard Ratio (HR): 1.52; 95% confidence interval (CI): 0.99, 2.34). A longer time to appropriate therapy was protective against mortality (HR: 0.79; 95% CI: 0.60, 1.03) except among the healthiest quartile of patients (HR: 1.44; 95% CI: 0.66, 3.15)., Conclusions/significance: Appropriate empiric therapy was not associated with decreased mortality in patients with S. aureus bacteremia except in the least ill patients. Initial broad antibiotic selection may not be widely beneficial.

This 5-year study of 25,378 hospitalizations measured the utility of infection control documentation of prior methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection for the optimization of empirical antibiotic therapy. Documented prior MRSA colonization or infection was predictive of subsequent MRSA infections (odds ratio, 4.05). Physicians appear to use this documentation when prescribing empirical therapy for suspected bacteremia.