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Background: Staphylococcus aureus bacteremia is associated with significant morbidity and mortality. To treat this infection, the current standard of care includes intravenous anti-staphylococcal beta-lactam antibiotics and obtaining adequate source control. Combination therapy with an aminoglycoside or rifampin, despite early promise, can no longer be routinely recommended due to an absence of proven benefit and risk of harm. Daptomycin is a rapidly acting bactericidal antibiotic that is approved for the treatment of Staphylococcus aureus bacteremia as monotherapy but has not been shown to be superior to the current standard of care. As demonstrated in vitro, the addition of daptomycin to beta-lactam therapy may result in enhanced anti-staphylococcal activity. Our objective is to assess the efficacy and safety of prescribing the combination of daptomycin with cefazolin or cloxacillin for the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia in adults. We hypothesize that adjunctive therapy with daptomycin will reduce the duration of bacteremia in this population., Methods: The DASH-RCT trial is a randomized, double blind, placebo-controlled trial designed per the Standard Protocol Items: Recommendation for Interventional Trials (SPIRIT) and Consolidated Standards of Reporting Trials (CONSORT) guidelines. We recruit adults with confirmed MSSA bacteremia, at the McGill University Health Center. Patients are eligible if they are 18 years or older, can receive cefazolin or cloxacillin monotherapy, and are enrolled within 72 h of the first blood culture being drawn. Exclusion criteria include anaphylaxis to study drugs, having polymicrobial bacteremia, anticipated hospital admission for < 5 days, and healthcare team refusal. While receiving standard of care, study patients are randomized to a 5-day course of adjunctive daptomycin or placebo. The trial began in December 2016 and is expected to end in December 2018, after recruiting an estimated 102 patients., Discussion: The DASH-RCT will compare the use of daptomycin as an adjunct to an anti-staphylococcal beta-lactam versus placebo in the treatment of MSSA bacteremia. We believe that a short course of dual therapy will result in earlier eradication of bacteremia and that subsequent research could evaluate effects on metastatic infection, relapse, and/or mortality. Ongoing issues in the trial include a delay between presentation of infection, enrollment in the trial, and the potential for unrecognized deep foci of infection at diagnosis., Trial Registration: ClinicalTrials.gov, NCT02972983 . Registered on 25 November 2016. Trial protocol: http://individual.utoronto.ca/leet/dash/dashprotocol.pdf.

Background: Widespread penicillin usage rapidly resulted in the emergence of penicillin resistance in Staphylococcus aureus. However, new data suggest that penicillin susceptibility may be in a period of renaissance. The objective of our study was to quantify penicillin resistance in methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia., Methods: We retrospectively reviewed all adult MSSA bacteremia from April 2010 to April 2015 at the McGill University Health Centre (Montreal, QC, Canada). Susceptibility to penicillin, erythromycin, clindamycin, and trimethoprim-sulfamethoxazole (TMP-SMX) was determined in accordance with the Clinical & Laboratory Standards Institute guidelines., Results: There were 324 unique episodes of MSSA bacteremia. Ninety (28%) isolates were susceptible to penicillin, 229 (71%) to erythromycin, 239 (74%) to clindamycin, and 317 (98%) to TMP-SMX. Isolates that were penicillin resistant were more likely to also be resistant to other antibiotics, but a statistically significant association was apparent only for erythromycin resistance (76/234, 32.2% vs 19/90, 21.1%, P = .04). The median age of patients was 67.5 years (interquartile range 52-78) and overall in-hospital 30-day mortality was 16.3% (53 deaths). After adjustment for patient age, there was no association between penicillin resistance and either intensive care unit admission or death., Conclusion: More than one-quarter of patients with MSSA bacteremia potentially could be treated with parenteral penicillin, which may offer pharmacokinetic advantages over other beta-lactam drugs and potentially improved outcomes., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Staphylococcus aureus bloodstream (SAB) infection is a common and severe infectious disease, with a 90-day mortality of 15%-30%. Despite this,

Staphylococcus aureus bloodstream (SAB) infection is a common and severe infectious disease, with a 90-day mortality of 15%–30%. Despite this, <3000 people have been randomized into clinical trials of treatments for SAB infection. The limited evidence base partly results from clinical trials for SAB infections being difficult to complete at scale using traditional clinical trial methods. Here we provide the rationale and framework for an adaptive platform trial applied to SAB infections. We detail the design features of the Staphylococcus aureus Network Adaptive Platform (SNAP) trial that will enable multiple questions to be answered as efficiently as possible. The SNAP trial commenced enrolling patients across multiple countries in 2022 with an estimated target sample size of 7000 participants. This approach may serve as an exemplar to increase efficiency of clinical trials for other infectious disease syndromes. [ABSTRACT FROM AUTHOR]

In Staphylococcus aureus bacteremia, mortality rates in randomized controlled trials (RCTs) are consistently lower than observational studies. Stringent eligibility criteria and omission of early deaths in RCTs contribute to this mortality gap. Clinicians should acknowledge the possibility of a lower treatment effect when applying RCT results to bedside care. [ABSTRACT FROM AUTHOR]

Background Deaths following Staphylococcus aureus bacteremia (SAB) may be related or unrelated to the infection. In SAB therapeutics research, the length of follow-up should be optimized to capture most attributable deaths and minimize nonattributable deaths. We performed a secondary analysis of a systematic review to describe attributable mortality in SAB over time. Methods We systematically searched Medline, Embase, and Cochrane Database of Systematic Reviews from 1 January 1991 to 7 May 2021 for human observational studies of SAB. To be included in this secondary analysis, the study must have reported attributable mortality. Two reviewers extracted study data and assessed risk of bias independently. Pooling of study estimates was not performed due to heterogeneity in the definition of attributable deaths. Results Twenty-four observational cohort studies were included. The median proportion of all-cause deaths that were attributable to SAB was 77% (interquartile range [IQR], 72%–89%) at 1 month and 62% (IQR, 58%–75%) at 3 months. At 1 year, this proportion was 57% in 1 study. In 2 studies that described the rate of increase in mortality over time, 2-week follow-up captured 68 of 79 (86%) and 48 of 57 (84%) attributable deaths that occurred by 3 months. By comparison, 1-month follow-up captured 54 of 57 (95%) and 56 of 60 (93%) attributable deaths that occurred by 3 months in 2 studies. Conclusions The proportion of deaths that are attributable to SAB decreases as follow-up lengthens. Follow-up duration between 1 and 3 months seems optimal if evaluating processes of care that impact SAB mortality. Clinical Trials Registration PROSPERO CRD42021253891. [ABSTRACT FROM AUTHOR]

Background Bloodstream infections (BSIs) with methicillin-susceptible Staphylococcus aureus (MSSA) are associated with significant morbidity and mortality. Our objective in this study was to determine the efficacy of synergistic treatment with daptomycin when given with either cefazolin or cloxacillin for the treatment of MSSA BSI. Methods A randomized, double-blind, placebo-controlled trial was performed at 2 academic hospitals in Montreal, Canada. Patients aged ≥18 years with MSSA BSI receiving either cefazolin or cloxacillin monotherapy were considered for inclusion. In addition to the standard-of-care treatment, participants received a 5-day course of adjunctive daptomycin or placebo. The primary outcome was the duration of MSSA BSI in days. Results Of 318 participants screened, 115 were enrolled and 104 were included in the intention-to-treat analysis (median age, 67 years; 34.5% female). The median duration of bacteremia was 2.04 days among patients who received daptomycin vs 1.65 days in those who received placebo (absolute difference, 0.39 days; P  = .40). In a modified intention-to-treat analysis that involved participants who remained bacteremic at the time of enrollment, we found a median duration of bacteremia of 3.06 days among patients who received daptomycin vs 3.0 days in those who received placebo (absolute difference, 0.06 days; P  = .77). Ninety-day mortality in the daptomycin arm was 18.9% vs 17.7% in the placebo arm (P  = 1.0). Conclusions Among patients with MSSA BSIs, the administration of adjunctive daptomycin therapy to standard-of-care treatment did not shorten the duration of bacteremia and should not be routinely considered. Clinical Trials Registration NCT02972983. [ABSTRACT FROM AUTHOR]

Background The effect of participation in a clinical trial on concomitant off-study investigational drug use has not been described. We sought to determine if participation in the Daptomycin as Adjunctive Therapy for Staphylococcus aureus bacteremia (DASH) trial increased overall daptomycin prescribing at study sites. Methods We retrospectively analyzed daptomycin use for 8 years preceding the trial, off-study daptomycin use during the trial itself (31 months), and daptomycin use for 6 fiscal months after trial completion. We used a segmented linear regression analysis of an interrupted time series to analyze changes in each drug's defined daily doses (DDD) per 1000 patient-days. As a control, we analyzed use of linezolid over these periods and also accounted for rates of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) infections. Results For 1.5 years before the DASH trial, daptomycin use was decreasing by –0.30 DDD per 1000 patient-days per fiscal period (95% CI, –0.52 to –0.07). Following the initiation of the study, there was a statistically significant increase in daptomycin use of 0.28 DDD per 1000 patient-days per fiscal period (95% CI, 0.03 to 0.52), despite low, stable rates of MRSA and VRE infections. Following trial completion, daptomycin use decreased back toward prestudy rates. Use of linezolid remained stable throughout. Conclusions Despite the DASH trial being a negative study, it impacted the prescribing habits of local clinicians during recruitment. Trialists should be aware of potential off-target study effects, and prescribers should be wary of early uptake of interventions before definitive study results. [ABSTRACT FROM AUTHOR]

Background Patients with hematologic malignancies (HM) are at risk of invasive fungal disease (IFD). Identification of those patients at the highest risk for IFD would help optimize prophylactic or preemptive treatment decisions in this population. We previously found that among patients with myeloid malignancies who develop invasive aspergillosis, 15% had a mutation in the gene GATA2. Here, we report the incidence of IFD in a cohort of patients with HM related to a pathogenic sequence variant of GATA2. Methods We identified 6343 patients cared for at Dana-Farber/Brigham and Women's Cancer Center between January 2014 and August 2018 who underwent a next-generation sequencing assay of 95 genes recurrently mutated in hematologic malignancy. Those found to have a pathogenic GATA2 sequence variant were selected for retrospective chart review with respect to serious infectious complications including IFD. Results We identified 54 patients with a pathogenic GATA2 variant. 5 had a germline mutation related to familial GATA2 deficiency. The other 49 had a HM, mostly (41/49) acute myeloid leukemia or myelodysplastic syndrome. The frequency of the variant GATA2 allele in this group ranged from 2.5 to 92.0% of sequencing reads. 14 patients were excluded due to lack of sufficient follow-up, often related to treatment at another institution. Of the remaining 35 patients, 13 (37%) had proven/probable invasive fungal infection (IFI). Fourteen others had syndromes consistent with possible IFD. In total, 16 of these 35 patients (46%) received antifungal therapy for proven, probable or possible IFD. Four of the patients not treated with antifungals were diagnosed with a serious infection including 2 cases of Staphylococcus aureus bacteremia, and one case of disseminated Mycobacterium avium complex. Conclusion We identified a high incidence of IFD among patients with HM related to a pathogenic sequence variant of GATA2. The wide range of variant allele frequency observed raises the possibility that either inherited or acquired GATA2 dysfunction could incur predisposition to infection. These data suggest that personalized genetic diagnostics of patients with HM may be useful for assessment of infectious risk. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

Background: Consideration to add empiric MRSA therapy with vancomycin is a common clinical dilemma. However, vancomycin overuse has important adverse events. MRSA colonization screening is commonly performed for infection control. We hypothesized that in cases of S. aureus bacteremia, a score based on patient level factors and MRSA colonization could predict the risk of MRSA infection and inform the need for empiric coverage.Methods: Using modern machine learning statistical methods (LASSO regression and random forests), we designed a predictive score for MRSA infection based on patient level characteristics, and MRSA colonization as measured by screening done 30 days before infection (30-Day criteria), or at any time before infection (Ever-Positive criteria). Patient factors (age, sex, number of previous admissions, and other medical comorbidities) were obtained through our electronic records.Results: With random forests, MRSA colonization largely surpassed all other factors in terms of accuracy and discriminatory power. Using LASSO regression, MRSA colonization was the only factor with MRSA infection predictive power with odds ratio of 10.3 (min: 5.99, max: 16.1) and 8.14 (min: 6.01, max: 14.8) for the 30-Day and Ever-Positive criteria, respectively. Further, patient comorbidities were not adequate predictors of MRSA colonization.Conclusions: In an era of community acquired MRSA, colonization status appears to be the only independent and reliable predictor of MRSA infection in cases of S. aureus bacteremia. A clinical approach based on a patient's known MRSA colonization status and on local susceptibility patterns may be appropriate. [ABSTRACT FROM AUTHOR]

• Styphylococcus aureus bacteremia (SAB) is common in low and middle-income countries (LMIC). • LMIC are poorly represented in SAB research. • In-hospital mortality for SAB is much higher in LMIC than in high-income countries. Staphylococcus aureus bacteremia (SAB) is a common infection worldwide. We compared SAB mortality in low- and middle-income countries (LMIC) versus high-income countries (HIC) in a meta-analysis. We searched MEDLINE, Embase, and Cochrane Database of Systematic Reviews from 1991-2021 and included observational, single-country studies on patients with positive blood cultures for S. aureus. The main outcome was the proportion of patients with SAB who died in the hospital. A generalized linear mixed random-effects model was used to pool estimates, and a meta-regression was used to adjust for study-level characteristics. A total of 332 studies involving 517,671 patients in 39 countries were included. No study was conducted in a low-income country. Only 33 (10%) studies were performed in middle-income countries (MIC), which described 6,216 patients. The pooled in-hospital mortality was 32.4% (95% confidence interval [CI] 27.2%-38.2%, T2 = 0.3063) in MIC and 22.3% (95% CI 20.1%-24.6%, T2 = 0.3257) in HIC. In a meta-regression model, MIC had higher in-hospital mortality (adjusted odds ratio 1.37, 95% CI 1.11-1.71; P = 0.0042) than HIC. In SAB studies, LMIC are poorly represented. In-hospital mortality was significantly higher in MIC than in HIC. Research should be conducted in LMIC to characterize differences in care processes driving the mortality gap. [ABSTRACT FROM AUTHOR]

Precise estimates of mortality in Staphylococcus aureus bacteraemia (SAB) are important to convey prognosis and guide the design of interventional studies. We performed a systematic review and meta-analysis to estimate all-cause mortality in SAB and explore mortality change over time. The MEDLINE and Embase databases, as well as the Cochrane Database of Systematic Reviews, were searched from January 1, 1991 to May 7, 2021. Human observational studies on patients with S. aureus bloodstream infection were included. The study analyzed data of patients with a positive blood culture for S. aureus. Two independent reviewers extracted study data and assessed risk of bias using the Newcastle–Ottawa Scale. A generalized, linear, mixed random effects model was used to pool estimates. A total of 341 studies were included, describing a total of 536,791 patients. From 2011 onward, the estimated mortality was 10.4% (95% CI, 9.0%–12.1%) at 7 days, 13.3% (95% CI, 11.1%–15.8%) at 2 weeks, 18.1% (95% CI, 16.3%–20.0%) at 1 month, 27.0% (95% CI, 21.5%–33.3%) at 3 months, and 30.2% (95% CI, 22.4%–39.3%) at 1 year. In a meta-regression model of 1-month mortality, methicillin-resistant S. aureus had a higher mortality rate (adjusted OR (aOR): 1.04; 95% CI, 1.02–1.06 per 10% increase in methicillin-resistant S. aureus proportion). Compared with prior to 2001, more recent time periods had a lower mortality rate (aOR: 0.88; 95% CI, 0.75–1.03 for 2001–2010; aOR: 0.82; 95% CI, 0.69–0.97 for 2011 onward). SAB mortality has decreased over the last 3 decades. However, more than one in four patients will die within 3 months, and continuous improvement in care remains necessary. [ABSTRACT FROM AUTHOR]