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Background: Staphylococcus aureus bloodstream infection (bacteremia) is traditionally treated with at least 2 weeks of intravenous (IV) antibiotics in adults, 3-7 days in children, and often longer for those with complicated disease. The current practice of treating S. aureus bacteremia (SAB) with prolonged IV antibiotics (rather than oral antibiotics) is based on historical observational research and expert opinion. Prolonged IV antibiotic therapy has significant disadvantages for patients and healthcare systems, and there is growing interest in whether a switch to oral antibiotics following an initial period of IV therapy is a safe alternative for clinically stable patients., Protocol: The early oral switch (EOS) domain of the S. aureus Network Adaptive Platform (SNAP) trial will assess early switch to oral antibiotics compared with continued IV treatment in clinically stable patients with SAB. The primary endpoint is 90-day all-cause mortality. Hospitalised SAB patients are assessed at platform day 7 ±2 (uncomplicated SAB) and day 14 ±2 (complicated SAB) to determine their eligibility for randomization to EOS (intervention) or continued IV treatment (current standard of care)., Discussion: Recruitment is occurring in the EOS domain of the SNAP trial. As of August 2023, 21% of all SNAP participants had been randomized to the EOS domain, a total of 264 participants across 77 centers, with an aim to recruit at least 1000 participants. We describe challenges and facilitators to enrolment in this domain to aid those planning similar trials., Competing Interests: Potential conflicts of interest. A. McGlothlin is an employee of Berry Consultants, LLC, a statistical consulting firm that specializes in the design of adaptive and platform clinical trials. Berry Consultants received compensation for work included in the content of the submission. A. C. Bowen reports participation as a member of the CAMERA-2 data and safety monitoring board (DSMB) and as chair of the Skin Trial DSMB; she also reports participation on Phage Trial DSMB and participation as Chair of FOSUTI DSMB; a role as Vice President of the World Society of Paediatric Infectious Diseases and as Co-Chair, Australian and New Zealand Pediatric Infectious Diseases group of the Australasian Society of Infectious Diseases (ASID). D. L. Paterson reports grants or contracts made to institution and unrelated to this work from Shionogi, Merck, and Pfizer; consulting fees to author from Antimicrobial Resistance Action Fund and Spero Therapeutics; payment or honoraria for lectures, presentations, speaker's bureaus, manuscript writing, or educational events to author from Pfizer and Merck; support for attending meetings and/or travel to author from Pfizer; and an unpaid leadership or fiduciary role with ASID. J. A. Roberts reports contracts or grants paid to institution and unrelated to this work from Pfizer and QPEX and investigator grant (APP2009736) and Advancing Queensland Clinical Fellowship; consulting fees paid to author from QPEX, Advanz Pharma, Gilead, Pfizer, Sandoz, Summit Pharma, and MSD; payment to author for lectures, presentations, speaker's bureaus, manuscript writing, or educational events from MSD, Gilead, Pfizer, and Cipla. J. Ten Oever reports grants or contracts unrelated to this work from Pfizer and MSD; support for attending meetings and/or travel to author from Pfizer; M. P. Cheng reports research support from the Canadian Institutes of Health Research and is supported by the Fonds de Recherche du Québec—Santé; research contracts from Cidara Therapeutics, Scynexis, and Amplyx Pharmaceuticals; consulting fees as a scientific consultant for AstraZeneca, Takeda, Merck, and Pfizer; 3 pending patents (Methods for detecting tissue damage, graft-versus-host disease, and infections using cell-free DNA profiling; Methods for assessing the severity and progression of SARS-CoV-2 infections using cell-free DNA; and rapid identification of antimicrobial resistance and other microbial phenotypes using highly multiplexed fluorescence in situ hybridization); stock options as a member of the scientific advisory board for GEn1E Lifesciences and Nomic Bio; and equity as co-founder of Kanvas Biosciences. R. J. Lewis is an employee of Berry Consultants, LLC, a statistical consulting firm that specializes in the design of adaptive and platform clinical trials. Berry Consultants received compensation for work included in the content of the submission. S. A. W. reports personal consulting fees from ClinicIQ pharma and Roche; an unpaid role as chair of Australian Clinical Trials Alliance; and stock and options with ClinicIQ. S. C. Morpeth reports grants or contracts unrelated to this work from the HRC, and a nonremunerated role as the Chair of the New Zealand Microbiology Network. S. Kalimuddin reports consulting fees from Gilead, Janssen, and Takeda (payments made to Singapore General Hospital) and grants or contracts unrelated to this work from National Medical Research Council, Singapore. S. Y. C. Tong reports a contract as a paid consultant for advice on clinical trial design, and consulting fees from Roivant Sciences as a paid consultant for advice on clinical trial design; and reports grants or contracts unrelated to this work from Australian National Health and Medical Research Council. T. C. Lee reports research salary support from Fonds de Recherche Quebec–Sante, operating funds for other studies including CATCO from the CIHR; and operating funds for other studies from the McGill Interdisciplinary Institute Infection and Immunity. Conflicts that the editors consider relevant to the content of the article have been disclosed. Collaborating authors have not been asked for their potential conflicts. A. Campbell reports National Health and Medical Research Council (grant 2014900) for SNAPPY and Perth Children's Hospital Foundation for site funding for SNAPPY and Raine Clinician Fellowship; participation on Data safety monitoring board for the B part of the NT Meningococcal B study; a role as Co-chair Australian and New Zealand Pediatric Infectious Diseases Special Interest Group Committee. A. Legg reports payment to author for Australian Pharmacy Council—EVUSHELD module and webinar and SHPA webinar; support for attending meetings and/or travel from Therapeutic Guidelines group meeting. L. Whiteway reports being remunerated for time attending meetings, and review of patient facing materials as consumer/PPI representative on the SNAP global trial steering committee. M. Bonten reports grants or contracts (all payments to UMCU) from Janssen Vaccines, Merck, LimmaTech, CureVac, Spherecydes; consulting fees (all payments to UMCU) from Janssen Vaccines, AstraZeneca, Pfizer, Sperecydes, Shionogi, GSK; participation on Data Safety Monitoring Board or Advisory Board for Sanofi (payments to UMCU). S. A. Webb reports grant from National Health and Medical Research Council of Australia that supports SNAP; personal consultings fees from ClinicIQ pharma and Roche; no patents or participation on Data Safety Monitoring Boards or Advisory Boards relevant to this work; unpaid roles as Chair and Director of Australian Clinical Trials Alliance; stock or stock options with Reliis. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

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., Competing Interests: Potential conflicts of interest. A. M. is an employee of Berry Consultants LLC, in which capacity she is contracted as a consultant to numerous pharmaceutical and device companies on topics of statistical modeling and trial design, and reports grants and contracts unrelated to this work and consulting fees from Berry Consultants LLC. A. C. B. reports participation as a member of the CAMERA-2 data and safety monitoring board (DSMB) and as chair of the Skin Trial DSMB; a role as Vice President of the World Society of Pediatric Infectious Diseases and as Co-Chair, Australian and New Zealand Paediatric Infectious Diseases group of the Australasian Society of Infectious Diseases (ASID). D. L. P. reports grants or contracts made to institution and unrelated to this work from Shionogi, Merck, and Pfizer; consulting fees to author from Antimicrobial Resistance Action Fund and Spero Therapeutics; payment or honoraria for lectures, presentations, speaker’s bureaus, manuscript writing, or educational events to author from Pfizer and Merck; support for attending meetings and/or travel to author from Pfizer; and an unpaid leadership or fiduciary role with ASID. J. A. R. reports contracts or grants paid to institution and unrelated to this work from the British Society of Antimicrobial Chemotherapy, bioMérieux, Pfizer, and QPEX; consulting fees paid to author from Gilead, Pfizer, Sandoz, Wolters Kluwer, Summit Pharma, and MSD; payment to author for lectures, presentations, speaker’s bureaus, manuscript writing, or educational events from MSD, Pfizer, and Cipla; an unpaid leadership or fiduciary role with Sepsis Clinical Care Standard, Australian Commission on Safety and Quality in Health Care, Consensus Guidelines on Prolonged Infusion of Beta-Lactam Antibiotics, American College of Clinical Pharmacy, Disease Modifying Treatment and Chemoprophylaxis, Australian National COVID-19 Clinical Evidence Taskforce, and Surviving Sepsis Guidelines. M. P. C. reports research support from the McGill Interdisciplinary Initiative in Infection and Immunity; research contracts from Cidara Therapeutics, Scynexis, and Amplyx; consulting fees as a scientific consultant for AstraZeneca; 3 pending patents (Methods for detecting tissue damage, graft-versus-host disease, and infections using cell-free DNA profiling; Methods for assessing the severity and progression of SARS-CoV-2 infections using cell-free DNA; and rapid identification of antimicrobial resistance and other microbial phenotypes using highly-multiplexed fluorescence in situ hybridization); stock options as a member of the scientific advisory board for GEn1E Lifesciences and Nomic Bio; and equity as co-founder of Kanvas Biosciences. R. J. L. is an employee of Berry Consultants, LLC, a statistical consulting firm that specializes in the design of adaptive and platform clinical trials. Berry Consultants received compensation for work included in the content of the submission. S. A. W. reports personal consulting fees from ClinicIQ pharma and Roche; an unpaid role as chair of Australian Clinical Trials Alliance; and stock and options with ClinicIQ. S. Y. C. T. reports a contract as a paid consultant for advice on clinical trial design, and consulting fees from Roivant Sciences as a paid consultant for advice on clinical trial design. T. C. L. reports research salary support from Fonds de Recherche Quebec–Sante, operating funds for other studies including CATCO from the CIHR; and operating funds for other studies from the McGill Interdisciplinary Institute Infection and Immunity. S. C. M. reports grants or contracts unrelated to this work from the HRC, and a nonremunerated role as the Chair of the New Zealand Microbiology Network. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

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., Competing Interests: Potential conflicts of interest. M. P. C. reports grants from McGill Interdisciplinary Initiative in Infection and Immunity and grants from Canadian Institutes of Health Research during the conduct of the study; personal fees from GEn1E Lifesciences (as a member of the scientific advisory board) and personal fees from nplex biosciences (as a member of the scientific advisory board) and consulting fees from Astra Zaneca outside the submitted work. He is the co-founder of Kanvas Biosciences and owns equity in the company. In addition, M. P. C. has a patent Methods for detecting tissue damage, graft versus host disease, and infections using cell-free DNA profiling pending (Cornell Reference number 9401-01-US), and a patent Methods for assessing the severity and progression of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections using cell-free DNA pending (Cornell Reference number 9561-01-US) and rapid identification of antimicrobial resistance and other microbial phenotypes using highly multiplexed fluorescence in situ hybridization (Cooley Reference: BEEB-001/00US 342794-2002). T. C. L. and E. G. M. receive research salary support from the Fonds de recherche du Québec – Santé. M. L. reports having served on advisory boards for Sanofi, Pfizer, Medicago, Merck, Seqirus, Paladin Labs; Pan Data Safety, and Monitoring Committees for Medicago, CanSino biologics, National Institutes of Health (NIH), the World Health Organization (WHO) EML Antibiotic Working Group. E. G. M. reports being co-investigator on the SNAP staph aureus platform trial CIHR outside of the submitted work. T. C. L. reports operating funds for other studies from Canadian Institutes of Health Research and McGill Interdisciplinary Institute Infection and Immunity. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Objectives: 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., Methods: 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., Results: 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%, T 2  = 0.3063) in MIC and 22.3% (95% CI 20.1%-24.6%, T 2  = 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., Conclusion: 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., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Precise estimates of mortality in Staphylococcus aureus bacteraemia (SAB) are important to convey prognosis and guide the design of interventional studies., Objectives: We performed a systematic review and meta-analysis to estimate all-cause mortality in SAB and explore mortality change over time., Data Sources: The MEDLINE and Embase databases, as well as the Cochrane Database of Systematic Reviews, were searched from January 1, 1991 to May 7, 2021., Study Eligibility Criteria: Human observational studies on patients with S. aureus bloodstream infection were included., Participants: The study analyzed data of patients with a positive blood culture for S. aureus., Methods: 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., Results: 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)., Conclusions: 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., (Copyright © 2022 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

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., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background and Objective: Enterococcus causes clinically significant bloodstream infections (BSIs). In centers with a higher prevalence of vancomycin resistant enterococcus (VRE) colonization, a common clinical question is whether empiric treatment directed against VRE should be initiated in the setting of a suspected enterococcal BSI. Unfortunately, VRE treatment options are limited, and relatively expensive, and subject patients to the risk of adverse reactions. We hypothesized that the results of VRE colonization screening could predict vancomycin resistance in enterococcal BSI., Methods: We reviewed 370 consecutive cases of enterococcal BSI over a 7-year period at 2 tertiary-care hospitals to determine whether vancomycin-resistant BSIs could be predicted based on known colonization status (ie, patients with swabs performed within 30 days, more remotely, or never tested). We calculated sensitivity and specificity, and we plotted negative predictives values (NPVs) and positive predictive values (PPVs) as a function of prevalence., Results: A negative screening swab within 30 days of infection yielded NPVs of 90% and 95% in settings where <27.0% and 15.0% of enterococcal BSI are resistant to vancomycin, respectively. In patients with known VRE colonization, the PPV for VRE in enterococcal BSI was >50% at any prevalence exceeding 25%., Conclusions: The results of a negative VRE screening test result performed within 30 days can help eliminate unnecessary empiric therapy in patients with suspected enterococcal BSI. Conversely, patients with positive VRE screening swabs require careful consideration of empiric VRE-directed therapy when enterococcal BSI appears likely.

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.

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.)

Bloodstream infections with Staphylococcus aureus are clinically significant and are often treated with empirical methicillin resistance (MRSA, methicillin-resistant S. aureus) coverage. However, vancomycin has associated harms. We hypothesized that MRSA screening correlated with resistance in S. aureus bacteremia and could help determine the requirement for empirical vancomycin therapy. We reviewed consecutive S. aureus bacteremias over a 5-year period at two tertiary care hospitals. MRSA colonization was evaluated in three ways: as tested within 30 days of bacteremia (30-day criterion), as tested within 30 days but accounting for any prior positive results (ever-positive criterion), or as tested in known-positive patients, with patients with unknown MRSA status being labeled negative (known-positive criterion). There were 409 S. aureus bacteremias: 302 (73.8%) methicillin-susceptible S. aureus (MSSA) and 107 (26.2%) MRSA bacteremias. In the 167 patients with MSSA bacteremias, 7.2% had a positive MRSA test within 30 days. Of 107 patients with MRSA bacteremia, 68 were tested within 30 days (54 positive; 79.8%), and another 21 (19.6%) were previously positive. The 30-day criterion provided negative predictive values (NPV) exceeding 90% and 95% if the prevalence of MRSA in S. aureus bacteremia was less than 33.4% and 19.2%, respectively. The same NPVs were predicted at MRSA proportions below 39.7% and 23.8%, respectively, for the ever-positive criterion and 34.4% and 19.9%, respectively, for the known-positive criterion. In MRSA-colonized patients, positive predictive values exceeded 50% at low prevalence. MRSA screening could help avoid empirical vancomycin therapy and its complications in stable patients and settings with low-to-moderate proportions of MRSA bacteremia., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Background Staphylococcus aureus bloodstream infection (bacteremia) is traditionally treated with at least 2 weeks of intravenous (IV) antibiotics in adults, 3–7 days in children, and often longer for those with complicated disease. The current practice of treating S. aureus bacteremia (SAB) with prolonged IV antibiotics (rather than oral antibiotics) is based on historical observational research and expert opinion. Prolonged IV antibiotic therapy has significant disadvantages for patients and healthcare systems, and there is growing interest in whether a switch to oral antibiotics following an initial period of IV therapy is a safe alternative for clinically stable patients. Protocol The early oral switch (EOS) domain of the S. aureus Network Adaptive Platform (SNAP) trial will assess early switch to oral antibiotics compared with continued IV treatment in clinically stable patients with SAB. The primary endpoint is 90-day all-cause mortality. Hospitalised SAB patients are assessed at platform day 7 ±2 (uncomplicated SAB) and day 14 ±2 (complicated SAB) to determine their eligibility for randomization to EOS (intervention) or continued IV treatment (current standard of care). Discussion Recruitment is occurring in the EOS domain of the SNAP trial. As of August 2023, 21% of all SNAP participants had been randomized to the EOS domain, a total of 264 participants across 77 centers, with an aim to recruit at least 1000 participants. We describe challenges and facilitators to enrolment in this domain to aid those planning similar trials. [ABSTRACT FROM AUTHOR]

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]

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: Vancomycin is often used as empiric therapy for methicillin-resistant Staphylococcus aureus (MRSA), but can be associated with clinically important adverse events including renal failure. MRSA colonization swabs are primarily used for infection control; their use as a diagnostic test to inform the decision to add empiric vancomycin therapy has not been well elucidated.Methods: We performed a Medline and Embase systematic review for peer-reviewed studies reporting the diagnostic accuracy of using MRSA colonization status to predict MRSA infections. Meta-analysis was performed using Cochrane guidelines. Grey literature was excluded.Findings: 29 studies were included involving 24225 patients. In cases where the pathogen is not known to be S. aureus, specificities were greater than 85% for bacteremia, lower respiratory tract infections, skin and soft tissue infections (SSTI), and all infections pooled together. Sensitivities ranged between 54.0% and 77.5%. In cases where the pathogen is known to be S. aureus, we found studies on bacteremia and SSTI and arrived at pooled estimates of sensitivities ranging between 56.6% and 56.9%, and of specificities greater than 91%. Most importantly, for most infections in settings where the prevalence of MRSA as a causative organism is below 15%, the negative predictive value of a negative MRSA colonization swab exceeds 90%.Interpretations: In settings of low-moderate MRSA prevalence, negative MRSA screening swabs may prevent unnecessary vancomycin use. More research is needed to assess if this strategy can mitigate the cost of screening in areas with a low MRSA colonization rate. [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]

The optimal treatment for potential AmpC-producing Enterobacteriaceae , including Serratia, Providencia, Citrobacter, Enterobacter , and Morganella species, remains unknown. An updated systematic review and meta-analysis of studies comparing beta-lactam/beta-lactamase inhibitors with carbapenems in the treatment of bloodstream infections with these pathogens found no significant difference in 30-day mortality (OR, 1.13; 95% CI, 0.58 – 2.20). [ABSTRACT FROM AUTHOR]