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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.)

Left ventricular assist devices (LVAD) are increasingly used for management of heart failure; infection remains a frequent complication. Phage therapy has been successful in a variety of antibiotic refractory infections and is of interest in treating LVAD infections. We performed a retrospective review of four patients that underwent five separate courses of intravenous (IV) phage therapy with concomitant antibiotic for treatment of endovascular Pseudomonas aeruginosa LVAD infection. We assessed phage susceptibility, bacterial strain sequencing, serum neutralization, biofilm activity, and shelf-life of phage preparations. Five treatments of one to four wild-type virulent phage(s) were administered for 14-51 days after informed consent and regulatory approval. There was no successful outcome. Breakthrough bacteremia occurred in four of five treatments. Two patients died from the underlying infection. We noted a variable decline in phage susceptibility following three of five treatments, four of four tested developed serum neutralization, and prophage presence was confirmed in isolates of two tested patients. Two phage preparations showed an initial titer drop. Phage biofilm activity was confirmed in two. Phage susceptibility alone was not predictive of clinical efficacy in P. aeruginosa endovascular LVAD infection. IV phage was associated with serum neutralization in most cases though lack of clinical effect may be multifactorial including presence of multiple bacterial isolates with varying phage susceptibility, presence of prophages, decline in phage titers, and possible lack of biofilm activity. Breakthrough bacteremia occurred frequently (while the organism remained susceptible to administered phage) and is an important safety consideration., Competing Interests: Saima Aslam: Research funding support from the Cystic Fibrosis Foundation, Armata Pharmaceuticals, Adaptive Phage Therapeutics, and Contrafect Inc. Consultant for BiomX and Phico Therapeutics. Medical advisory board for Pherecydes Pharma and Phiogen. Dwayne Roach: none. Mikeljon P. Nikolich: Royalty-bearing Biological Material License Agreement with Adaptive Phage Therapeutics exists now but work presented in this manuscript predated it. Patent PCT/US22/73852, METHOD OF TREATING DRUG RESISTANT ESKAPE PATHOGENS USING THERAPEUTIC BACTERIOPHAGES was filed, but work reported in this manuscript predated the filing. Biswajit Biswas: Navy Work Unit # A1417. Dr. Biswas has a patent "Bacteriophage compositions and methods of selection of components against specific bacteria" US patent #10357522, which was licensed before. Robert T Schooley: Consulting fees from GSK, LyseNtech. Kimberley A. Lilly-Bishop: none. Gregory K. Rice: none. Regina Z. Cer: none. Theron Hamilton: none. Mathew Henry: Mr. Henry has a patent 10357522 licensed. Tiffany Luong: none. Ann-Charlott Salabarria: none. Laura Sisk-Hackworth: none. Andrey A. Filippov: Pending Patent PCT/US22/73852, METHOD OF TREATING DRUG RESISTANT ESKAPE PATHOGENS USING THERAPEUTIC BACTERIOPHAGES Francois Lebreton: none. Lindsey Hall: none. Ran Nir-Paz: Consultant for BiomX; and has participated and served as a PI and on Data Safety Monitoring Board for a clinical trial by Technophage. Hadil Onalla: none. Gilat Livni: none. Eran Shostak: none. Anat Weider-Feinsod: none. Dafna Yahav: none. Ortal Yerushalmy: none. Sivan Alkalay-Oren: none. Leron Khalifa: none. Amit Rimon: none. Daniel Gelman: none. Ronen Hazan: none.

Background: P. aeruginosa bacteremia is a common and severe infection carrying high mortality in older adults. We aimed to evaluate outcomes of P. aeruginosa bacteremia among old adults (≥ 80 years)., Methods: We included the 464/2394 (19%) older adults from a retrospective multinational (9 countries, 25 centers) cohort study of individuals hospitalized with P. aeruginosa bacteremia. Bivariate and multivariable logistic regression models were used to evaluate risk factors for 30-day mortality among older adults., Results: Among 464 adults aged ≥ 80 years, the mean age was 84.61 (SD 3.98) years, and 274 (59%) were men. Compared to younger patients, ≥ 80 years adults had lower Charlson score; were less likely to have nosocomial acquisition; and more likely to have urinary source. Thirty-day mortality was 30%, versus 27% among patients 65-79 years (n = 894) and 25% among patients < 65 years (n = 1036). Multivariate analysis for predictors of mortality among patients ≥ 80 years, demonstrated higher SOFA score (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.23-1.51, p < 0.001), corticosteroid therapy (OR 3.15, 95% CI: 1.24-8.01, p = 0.016) and hospital acquired P. aeruginosa bacteremia (OR 2.30, 95% CI: 1.33-3.98, p = 0.003) as predictors. Appropriate empirical therapy within 24 h, type of definitive anti-pseudomonal drug, and type of regimen (monotherapy or combination) were not associated with 30-day mortality., Conclusions: In older adults with P. aeruginosa bacteremia, background conditions, place of acquisition, and disease severity are associated with mortality, rather than the antimicrobial regimen. In this regard, preventive efforts and early diagnosis before organ failure develops might be beneficial for improving outcomes., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Introduction: Reports regarding the external validity of randomized controlled trials (RCTs) are scarce. We aimed to assess the population external validity of an investigator-initiated RCT on the duration of antibiotics for the treatment of Gram-negative bacteremia by comparing patients included in the RCT to patients that were not included in the trial., Methods: Hospitalized patients with Gram-negative bacteremia were recruited into an RCT and randomized to receive 7 or 14 days of covering antibiotic therapy in Israel and Italy from 2013 to 2017. In a concomitant observational study, RCT participants were compared with patients who fulfilled the inclusion criteria but were not included in the trial due to participation in other trials, discharge before approached by researchers, refusal to participate, or unwillingness of the treating physician to allow participants' recruitment., Results: Six hundred and four RCT patients were compared with 613 nonincluded patients. Almost 50% of nonincluded patients (288/613) were dependent on others for activities of daily living at baseline compared to 37.7% of RCT participants (228/604). Dementia was nearly 2-fold more frequent in nonincluded patients than those included (5.9% [36/613] versus 3.6% [22/604], p = 0.07). Patients who were not included in the RCT were more likely to acquire their infection in the hospital (53.3% [327/613] versus 29.1% [176/604], p < 0.001). The primary composite outcome of mortality, clinical failure, readmissions, or extended hospitalization at 90 days occurred in 353 of 613 nonincluded patients (57.6%) compared to 299 of 604 RCT participants (49.6%), p = 0.005. However, on multivariate analysis noninclusion in the RCT was not an independent risk factor for clinical failure and mortality., Conclusions: RCTs, even with broad eligibility criteria, do not represent the whole spectrum of patients and leave out a population with more severe illness for whom the evidence is lacking., (© 2022 S. Karger AG, Basel.)

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.)

There is no consensus regarding the optimal duration of antibiotic therapy for urinary tract infection (UTI) following kidney transplantation (KT). We performed a retrospective study comparing short (6-10 days) versus prolonged (11-21 days) antibiotic therapy for complicated UTI among KT recipients. Univariate and inverse probability treatment weighted (IPTW) adjusted multivariate analysis for composite primary outcome of all-cause mortality or readmissions within 30 days and relapsed UTI 180 days were performed. Overall, 214 KT recipients with complicated UTI were included; 115 short-course treatment (median 8, interquartile range [IQR] 6-9 days), 99 prolonged course (median 14, IQR 12-21 days). The composite outcome occurred in 33 (28.6%) in the short-course group and 30 (30%) in the prolonged-course group; relapsed UTI occurred in 19 (16.5%) vs. 21 (21%), respectively. Duration of antibiotic treatment was not associated with any of these outcomes. The only risk factor for mortality/readmissions in multivariate analysis was deceased donor. No differences between groups were demonstrated for length of hospital stay, rates of bacteraemia, resistance development, and serum creatinine at 30 and 90 days. In conclusion, we found no difference in clinical outcomes between KT recipients treated for complicated UTI with short-course antibiotic (6-10 days) versus longer course (11-21 days)., (© 2021 Steunstichting ESOT. Published by John Wiley & Sons Ltd.)

Purpose of Review: Gram-negative bloodstream infections (GNBSI) are common and carry considerable mortality. Treatment is complicated by increasing antimicrobial resistance, posing a challenge for timely appropriate antibiotics and limiting the choices of effective definitive therapy. The present review aims to summarize recent studies addressing the management of GNBSI., Recent Findings: New rapid diagnostic tests (RDT) for pathogen identification and antibiotic susceptibility are associated with improved antimicrobial stewardship and reduced length of stay. No mortality benefit or patient-related outcomes are reported. Data regarding the use of new beta-lactam beta-lactamase inhibitors (BLBLIs) for treating multidrug resistance Gram-negative bacteria is supportive, though questions regarding combinations, optimal dosing, mode of administration, and resistance emergence remain to be clarified. Current data regarding cefiderocol necessitates further studies in order to support its use in GNBSI. Shortened (≤7 days) duration of therapy and early oral step down for GNBSI are supported by the literature. The role of repeated blood cultures should be further defined., Summary: RDTs should be implemented to improve antibiotic stewardship. Clinical implications on patient-related outcomes should be evaluated. New BLBLIs show promise in the treatment of GNBSI. Additional data are needed regarding the use of cefiderocol. Antibiotic therapy should be shortened and early oral step down should be considered., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Pseudomonas aeruginosa bacteraemia is a common and serious infection. No consensus exists regarding whether definitive combination therapy is superior to monotherapy. We aimed to evaluate the impact of combination therapy on mortality., Methods: This was a multicentre retrospective study (nine countries, 25 centres), including 1277 patients with P. aeruginosa bacteraemia during 2009-15. We evaluated the association between β-lactam plus aminoglycoside or quinolone combination therapy versus β-lactam monotherapy and mortality. The primary outcome was 30 day all-cause mortality. Univariate and multivariate Cox regression analyses were conducted, introducing combination as a time-dependent variable. Propensity score was conducted to adjust for confounding for choosing combination therapy over monotherapy., Results: Of 1119 patients included, 843 received definitive monotherapy and 276 received combination therapy (59% aminoglycoside and 41% quinolone). Mortality at 30 days was 16.9% (189/1119) and was similar between combination (45/276; 16.3%) and monotherapy (144/843; 17.1%) groups (P = 0.765). In multivariate Cox regression, combination therapy was not associated with reduced mortality (HR 0.98, 95% CI 0.64-1.53). No advantage in terms of clinical failure, microbiological failure or recurrent/persistent bacteraemia was demonstrated using combination therapy. Likewise, adverse events and resistance development were similar for the two regimens., Conclusions: In this retrospective cohort, no mortality advantage was demonstrated using combination therapy over monotherapy for P. aeruginosa bacteraemia. Combination therapy did not improve clinical or microbiological failure rates, nor affect adverse events or resistance development. Our finding of no benefit with combination therapy needs confirmation in well-designed randomized controlled trials., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Bloodstream infections (BSI) represent a serious bacterial infection with substantial morbidity and mortality. Population-based studies demonstrate an increased incidence, especially among elderly patients. Controversy exists regarding whether presentation of BSI are different in older patients compared to younger patients; our narrative review of the literature suggests that BSI in elderly patients would probably include one or more of the traditional symptoms/signs of fever, severe sepsis or septic shock, acute kidney injury, and/or leukocytosis. Sources of BSI in older adults are most commonly the urinary tract (more so than in younger adults) and the respiratory tract. Gram-negative bacteria are the most common isolates in the old (~ 40-60% of BSI); isolates from the elderly patient population show higher antibiotic resistance rates, with long-term care facilities serving as reservoirs for multidrug-resistant bacteria. BSI entail significantly higher rates of mortality in older age, both short and long term. Some of the risk factors for mortality are modifiable, such as the appropriateness of empirical antibiotic therapy and nosocomial acquisition of infection. Health-related quality of life issues regarding the elderly patient with BSI are not well addressed in the literature. Utilization of comprehensive geriatric assessment and comprehensive geriatric discharge planning need to be investigated further in this setting and might serve as key for improved results in this population. In this review, we address all these aspects of BSI in old patients with emphasis on future goals for management and research.

Objective: Carbapenems are considered treatment of choice for bacteremia caused by potential AmpC-producing bacteria, including Enterobacter spp. We aimed to compare mortality following carbapenem vs. alternative antibiotics for the treatment of Enterobacter spp. bacteremia. Patients and Methods: We conducted a retrospective study in two centers in Israel. We included hospitalized patients with Enterobacter bacteremia treated with third-generation cephalosporins (3GC), piperacillin/tazobactam, quinolones, or carbapenem monotherapy as the main antibiotic in the first week of treatment, between 2010 and 2017. Cefepime was excluded due to nonavailability during study years. The primary outcome was 30-day all-cause mortality. Univariate and multivariate analyses were conducted, introducing the main antibiotic as an independent variable. Results: Two hundred seventy-seven consecutive patients were included in the analyses. Of these, 73 were treated with 3GC, 39 with piperacillin/tazobactam, 104 with quinolones, and 61 with carbapenems. All-cause 30-day mortality was 16% (45 patients). The type of antibiotics was not significantly associated with mortality on univariate or multivariate analyses. With carbapenems as reference, adjusted odds ratios (ORs) for mortality were 0.708, 95% confidence interval (CI) 0.231-2.176 with 3GC; OR 1.172, 95% CI 0.388-3.537 with piperacillin/tazobactam; and OR 0.586, 95% CI 0.229-1.4 with quinolones. The main antibiotic was not associated with repeated growth of Entrobacter spp. in blood cultures or other clinical specimens. Resistance development was observed with 3GC and piperacillin/tazobactam. Conclusions: Carbapenem treatment was not advantageous to alternative antibiotics, including 3GC, among patients with Enterobacter spp. bacteremia in an observational study.

Background: Recent data regarding polymicrobial bacteremia (PMB) are lacking., Objectives: To characterize risk factors as well as clinical, microbiological, and prognostic patterns of patients with PMB in a modern hospital setting., Methods: A single center retrospective study including all patients diagnosed with PMB during 2013 was conducted. PMB was defined as two or more organisms cultured from the blood of the same patient within 72 hours. Patients with monomicrobial infections served as controls., Results: There were 135 episodes (2% of all bacteremia episodes) of true PMB among 123 patients during the study period. Recent invasive procedures (odds ratio [OR] 3.59, 95% confidence interval [95%CI] 1.41-9.12, P = 0.006) and foreign bodies (OR 1.88, 95%CI 1.06-3.33, P = 0.04) were risk factors for PMB when compared with 79 patients with monomicrobial bacteremia. Central-line-associated infections were the most common infection source among patients with PMB (n=34, 28%). Enterobacteriaceae were the most commonly implicated pathogen (n=95, 77%). Non-fermenting Gram-negative bacilli were significantly more common than previously reported (n=55, 45%). Although crude 30-day mortality was higher (48% vs. 33%) in PMB patients, adjusted mortality was comparable in the two groups., Conclusions: PMB rate in our cohort was considerably lower than in previous reports. Central-line-associated infections were more common than classic PMB sources. Mortality remained high. Strategies for early identification and better care for these patients should be pursued.

Importance: Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with mortality of more than 20%. Combining standard therapy with a β-lactam antibiotic has been associated with reduced mortality, although adequately powered randomized clinical trials of this intervention have not been conducted., Objective: To determine whether combining an antistaphylococcal β-lactam with standard therapy is more effective than standard therapy alone in patients with MRSA bacteremia., Design, Setting, and Participants: Open-label, randomized clinical trial conducted at 27 hospital sites in 4 countries from August 2015 to July 2018 among 352 hospitalized adults with MRSA bacteremia. Follow-up was complete on October 23, 2018., Interventions: Participants were randomized to standard therapy (intravenous vancomycin or daptomycin) plus an antistaphylococcal β-lactam (intravenous flucloxacillin, cloxacillin, or cefazolin) (n = 174) or standard therapy alone (n = 178). Total duration of therapy was determined by treating clinicians and the β-lactam was administered for 7 days., Main Outcomes and Measures: The primary end point was a 90-day composite of mortality, persistent bacteremia at day 5, microbiological relapse, and microbiological treatment failure. Secondary outcomes included mortality at days 14, 42, and 90; persistent bacteremia at days 2 and 5; acute kidney injury (AKI); microbiological relapse; microbiological treatment failure; and duration of intravenous antibiotics., Results: The data and safety monitoring board recommended early termination of the study prior to enrollment of 440 patients because of safety. Among 352 patients randomized (mean age, 62.2 [SD, 17.7] years; 121 women [34.4%]), 345 (98%) completed the trial. The primary end point was met by 59 (35%) with combination therapy and 68 (39%) with standard therapy (absolute difference, -4.2%; 95% CI, -14.3% to 6.0%). Seven of 9 prespecified secondary end points showed no significant difference. For the combination therapy vs standard therapy groups, all-cause 90-day mortality occurred in 35 (21%) vs 28 (16%) (difference, 4.5%; 95% CI, -3.7% to 12.7%); persistent bacteremia at day 5 was observed in 19 of 166 (11%) vs 35 of 172 (20%) (difference, -8.9%; 95% CI, -16.6% to -1.2%); and, excluding patients receiving dialysis at baseline, AKI occurred in 34 of 145 (23%) vs 9 of 145 (6%) (difference, 17.2%; 95% CI, 9.3%-25.2%)., Conclusions and Relevance: Among patients with MRSA bacteremia, addition of an antistaphylococcal β-lactam to standard antibiotic therapy with vancomycin or daptomycin did not result in significant improvement in the primary composite end point of mortality, persistent bacteremia, relapse, or treatment failure. Early trial termination for safety concerns and the possibility that the study was underpowered to detect clinically important differences in favor of the intervention should be considered when interpreting the findings., Trial Registration: ClinicalTrials.gov Identifier: NCT02365493.

This study aimed to evaluate risk factors for 30-day mortality among hospitalised patients with Pseudomonas aeruginosa bacteraemia, a highly fatal condition. A retrospective study was conducted between 1 January 2009 and 31 October 2015 in 25 centres (9 countries) including 2396 patients. Univariable and multivariable analyses of risk factors were conducted for the entire cohort and for patients surviving ≥48 h. A propensity score for predictors of appropriate empirical therapy was introduced into the analysis. Of the 2396 patients, 636 (26.5%) died within 30 days. Significant predictors (odds ratio and 95% confidence interval) of mortality in the multivariable analysis included patient-related factors: age (1.02, 1.01-1.03); female sex (1.34, 1.03-1.77); bedridden functional capacity (1.99, 1.24-3.21); recent hospitalisation (1.43, 1.07-1.92); concomitant corticosteroids (1.33, 1.02-1.73); and Charlson comorbidity index (1.05, 1.01-1.93). Infection-related factors were multidrug-resistant Pseudomonas (1.52, 1.15-2.1), non-urinary source (2.44, 1.54-3.85) and Sequential Organ Failure Assessment (SOFA) score (1.27, 1.18-1.36). Inappropriate empirical therapy was not associated with increased mortality (0.81, 0.49-1.33). Among 2135 patients surviving ≥48 h, hospital-acquired infection (1.59, 1.21-2.09), baseline endotracheal tube (1.63, 1.13-2.36) and ICU admission (1.53, 1.02-2.28) were additional risk factors. Risk factors for mortality among patients with P. aeruginosa were mostly irreversible. Early appropriate empirical therapy was not associated with reduced mortality. Further research should be conducted to explore subgroups that may not benefit from broad-spectrum antipseudomonal empirical therapy. Efforts should focus on prevention of infection, mainly hospital-acquired infection and multidrug-resistant pseudomonal infection., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: The Flavobacteriaceae family includes rare pathogens in children; Chryseobacterium indologenes and Elizabethkingia meningosepticum are the most common pathogenic species, with a wide range of clinical presentations and high mortality rate. Although rare, diagnosis is important due to inherent resistance to multiple antibiotics, especially those typically prescribed for empiric treatment of aerobic Gram-negative bacterial infections., Methods: A multicenter retrospective study conducted in 5 Israeli hospitals, describing Flavobacteriaceae bacteremia confirmed by positive blood culture from 1998 to 2018., Results: Thirteen cases were included; 9 isolates were C. indologenes. Bacteremia was nosocomial or healthcare-associated in all cases. Bacteremia was associated with young age (median, 1 year, range 24 days-17 years), with only 2 (15.4%) cases in neonates, Central line-associated bloodstream infection as a source (5/13, 38%) and malignancy (7/13, 54.8%). Thirty-day all-cause mortality was 23% (3/13). Ninety-one percent of isolates were susceptible to trimethoprim-sulfamethoxazole, 82% to piperacillin-tazobactam and 92% to ciprofloxacin., Conclusions: C. indologenes and E. meningosepticum are rare, nosocomial- or healthcare-associated pediatric bacteremia pathogens. Bacteremia was associated with young age, but in contrast to the literature, the majority of our cases were older than the neonatal age period. In addition, they were associated with central line-associated bloodstream infection and malignancy. The most adequate antibiotics according to resistance patterns were ciprofloxacin, trimethoprim-sulfamethoxazole and piperacillin-tazobactam.

Background: Gram-negative bacteremia is a major cause of morbidity and mortality in hospitalized patients. Data to guide the duration of antibiotic therapy are limited., Methods: This was a randomized, multicenter, open-label, noninferiority trial. Inpatients with gram-negative bacteremia, who were afebrile and hemodynamically stable for at least 48 hours, were randomized to receive 7 days (intervention) or 14 days (control) of covering antibiotic therapy. Patients with uncontrolled focus of infection were excluded. The primary outcome at 90 days was a composite of all-cause mortality; relapse, suppurative, or distant complications; and readmission or extended hospitalization (>14 days). The noninferiority margin was set at 10%., Results: We included 604 patients (306 intervention, 298 control) between January 2013 and August 2017 in 3 centers in Israel and Italy. The source of the infection was urinary in 411 of 604 patients (68%); causative pathogens were mainly Enterobacteriaceae (543/604 [90%]). A 7-day difference in the median duration of covering antibiotics was achieved. The primary outcome occurred in 140 of 306 patients (45.8%) in the 7-day group vs 144 of 298 (48.3%) in the 14-day group (risk difference, -2.6% [95% confidence interval, -10.5% to 5.3%]). No significant differences were observed in all other outcomes and adverse events, except for a shorter time to return to baseline functional status in the short-course therapy arm., Conclusions: In patients hospitalized with gram-negative bacteremia achieving clinical stability before day 7, an antibiotic course of 7 days was noninferior to 14 days. Reducing antibiotic treatment for uncomplicated gram-negative bacteremia to 7 days is an important antibiotic stewardship intervention., Clinical Trials Registration: NCT01737320., (© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Early infections are common during the first month after liver transplantation (LT), whereas no consensus exists on the optimal prophylactic antimicrobial therapy. We aimed to evaluate the effectiveness of cefazolin perioperative prophylaxis in LT., Patients and Methods: We documented our experience with single-dose cefazolin as prophylaxis for LT. Infections occurring within 30 days following LT during 2006-2015 were documented retrospectively. Univariate and multivariate analyses of risk factors for infection were carried out., Results: Among 113 LT recipients receiving cefazolin as prophylaxis, infections occurred in 50 (44%) patients, including surgical site infections (n=24, 21%) and bacteremia (n=14, 12%). Bacteria resistant to cefazolin were documented in 59/72 (82%) isolates. Enterococcal infections were documented in 6% (7/113). Almost half of the infections (44%) occurred in the first week following LT and the vast majority within 2 weeks. The 30-day mortality rate (7%, 8/113) was significantly higher among infected patients (7/50, 14% vs. 1/63, 1.6%, P=0.011). Model for End-stage Liver Disease score, age, and requirement for at least 5 U of packed red cells during transplantation were predictive for postoperative infections., Conclusion: In our center, cefazolin was insufficient as perioperative prophylaxis in LT. We suggest that all LT recipients should receive antibiotic prophylaxis targeting microorganisms on the basis of local bacterial ecology and patterns of resistance irrespective of preoperative or intraoperative risk assessment.

Background: Desirability of outcome ranking (DOOR) is an innovative approach in clinical trials to evaluate the global benefits and risks of an intervention. We developed and validated a DOOR endpoint for Staphylococcus aureus bloodstream infection (BSI) through a survey to infectious diseases clinicians and secondary analysis of trial data., Methods: We administered a survey of 20 cases of S. aureus BSI, asking respondents to rank outcomes by global desirability. Correlations and percentage of pairwise agreement among rankings were estimated to inform development of a DOOR endpoint, which was applied to 2 prior S. aureus BSI trials. The probability that a patient randomly assigned to experimental treatment would have a better DOOR ranking than if assigned to control was estimated. Results were also analyzed using partial credit, which is analogous to scoring an academic test, assigning 100% to the most desirable outcome, 0% to the least, and "partial credit" to intermediate ranks., Results: Forty-two recipients (97%) completed the survey. The DOOR endpoint fitting these rankings (r = 0.89; 95% confidence interval, 0.67 to 0.94) incorporated survival plus cumulative occurrence of adverse events, cure, infectious complications, and ongoing symptoms. Tailored versions of this endpoint were applied to 2 S. aureus BSI trials, and both demonstrated no benefit of the experimental treatment using DOOR and partial credit analysis., Conclusions: Using S. aureus BSI as an exemplar, we developed a DOOR endpoint that can be used as a template for development of DOOR endpoints for other diseases. Future trials can incorporate DOOR to allow for global assessment of patient experience., (© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Use of GeneXpert MRSA/SA in diagnostic algorithms of Staphylococcus aureus bacteremia may influence both patients' clinical outcomes and antibiotic stewardship. We evaluated these outcomes in a retrospective cohort before (1/6/2015-31/5/2016) and after (1/6/2016-31/8/2017) the introduction of the test in adult patients with Gram-positive cocci in clusters in blood cultures. We included 254 patients (125 preintervention, 129 postintervention). No significant difference in 30-day mortality or clinical success was demonstrated between periods. Appropriate antibiotic therapy rates were significantly higher in the postintervention group, and vancomycin use was significantly reduced (80.6% vs 53.6%, P < 0.01; 2.3±0.38 vs 2.98±1.02 defined daily doses/100 patient days, P = 0.026, respectively). Appropriate beta-lactam use was also significantly higher (56.7% postintervention vs 23.1% preintervention, P < 0.01). Use of GeneXpert MRSA/SA test has a positive effect on antibiotic stewardship measures, though it has no significant effect on clinical outcomes including mortality in this fatal infection., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Bloodstream infections (BSIs) are an important cause of hospitalizations and mortality among hemodialysis (HD) patients. Epidemiology of these infections is changing, with increasing rates of Gram-negative pathogens, including resistant ones. Few studies have focused on the characteristics and outcomes of these infections., Objective: We aimed to document the causative pathogens of BSIs in HD patients and their clinical outcomes during 2008 - 2015, and to compare risk factors, clinical features, appropriateness of therapy, and outcomes between patients with Gram-negative vs. Gram-positive BSIs., Materials and Methods: A single-center retrospective cohort study. Charts of 120 HD patients hospitalized with first BSI were reviewed., Results: A total of 120 patients were included, 61 episodes of Gram-negative (51.8%) and 59 episodes of Gram-positive bacteria (49.2%). Source of infection was significantly more likely to be urinary or abdominal among patients with Gram-negative infection. Otherwise, no statistically significant differences were documented between groups in terms of baseline characteristics, presentation of infection and outcomes. Most Gram-negative BSIs were caused by enterobacteriaceae, followed by Pseudomonas spp. Previous clinical or surveillance cultures added little to accurate prediction of the causative organism., Conclusion: In a cohort of HD patients with BSI, no significant differences were found between Gram-negative and Gram-positive BSIs, besides source of infection. A urinary or abdominal source strongly suggests a Gram-negative pathogen. Otherwise, patient's characteristics, clinical presentation, and previous cultures, all cannot accurately predict the causative pathogen of BSI, and broad-spectrum antibiotics should be used empirically.
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The objective of this study was to explore whether the percentage of inappropriate empirical antibiotic treatment in patients with bacteremia changed over time and to understand the factors that brought on the change. Three prospective cohorts of patients with bacteremia in three different periods (January 1st, 1988 to December 31st, 1989; May 1st, 2004 to November 30, 2004; May 1st, 2010 to April 30, 2011) were compared. Analysis was performed on a total of 811 patients. In 2010-2011, 55.9% (76/136) of patients with bacteremia received inappropriate empirical treatment, compared with 34.5% (170/493) and 33.5% (55/164) in the first and second periods, respectively, in a significant upward trend (p = 0.001). Resistance to antibiotics increased significantly during the study period. The following variables were included in the multivariate analysis assessing risk factors for inappropriate empirical treatment: study period (third period) [odds ratio, OR = 2.766 (95% confidence interval, CI, 1.655-4.625)], gender (male) [OR = 1.511 (1.014-2.253)], pathogen carrying extended-spectrum beta-lactamases [OR = 10.426 (4.688-23.187)], multidrug-resistant Acinetobacter baumannii [OR = 5.428 (2.181-13.513)], and skin/soft infections [OR = 3.23 (1.148-9.084)]. A model excluding microbiological data included: gender (male) [OR = 1.648 (1.216-2.234)], study period (third period) [OR = 2.446 (1.653-3.620)], hospital-acquired infection [OR = 1.551 (1.060-2.270)], previous use of antibiotics [OR = 1.815 (1.247-2.642)], bedridden patient [OR = 2.019 (1.114-3.658)], and diabetes mellitus [OR = 1.620 (1.154-2.274)]. We have observed a worrisome increase in the rate of inappropriate empirical treatment of bacteremia. We need tools that will allow us better prediction of the pathogen and its susceptibilities during the first hours of managing a patient suspected of a severe bacterial infection.

Aim: The incidence of Staphylococcus aureus bacteremia (SAB) increases with advancing age with higher mortality reported in older adults. We aimed to describe the clinical presentation, management and outcomes of older patients with SAB., Methods: We analyzed data from a retrospectively collected database including 1692 patients with SAB, and compared 1158 older patients (≥65 years) with 534 younger patients (<65 years) in terms of clinical features, management of infection, and outcomes., Results: Older patients were significantly less likely to be febrile on presentation, with 37.5 % (415/1106) of older patients presenting with normal body temperature [versus 29.2 % (152/520) of younger patients]. Older patients were however, more likely to have leukocytosis, septic shock, lower heart rate and lower diastolic blood pressure compared with younger patients. Management of older patients included significantly less imaging studies, performance of transesophageal echocardiogram (TEE) and infectious diseases consultation. TEE was performed less in older patients [124/726 (17.1 %) versus 72/285 (25.3 %)]. Mortality was significantly higher in older patients [550/1158 (47.5 %) versus 124/534 (23.2 %)], with predictors for mortality for the entire cohort in multivariate analysis including older age, higher Charlson comorbidity index, female sex, impaired functional capacity, pneumonia or primary bacteremia, and non-performance of TEE., Conclusions: Mortality rates in older patients with SAB are higher compared with younger patients. Several diagnostic and therapeutic procedures in the management of SAB were less likely to be performed in older patients in our cohort. These may have implications on outcome and should not be dismissed on the basis of age alone.

Introduction: Changes in the epidemiology of Staphylococcus aureus bacteremia (SAB) have been described in recent decades. Decreased mortality has been reported over time, mostly from countries with low methicillin resistance rates. We aimed to describe time trends in SAB in a tertiary center with high methicillin resistance rates., Methods: We retrospectively analyzed 1692 patients with SAB, and compared between three time periods: 1988-1994 (342 patients), 1998-2004 (597 patients) and 2005-2010 (753 patients)., Results: In our cohort, 30 days mortality increased significantly with time, reaching 42.9 % during 2005-2010. The latter period was characterized by higher rates of older patients (35.1 % aged 80 years and older), with lower functional capacity (46.5 % bedridden) and higher rates of comorbidities (33.6 % renal disease, 24.8 % heart failure, 19.0 % dementia). These patients were more likely to be ventilated (18.7 %) and carry a urinary catheter at presentation (46.6 %); present with septic shock (15.9 %) and have pneumonia (20.5 %) or endocarditis (7.2 %) as source. Similar characteristics were found among patients younger than 50 years and with independent functional status. No significant increase in methicillin resistant Staph aureus (MRSA) rates or inappropriate empirical therapy was demonstrated during 2005-2010., Conclusions: In our cohort, increased mortality in recent years in patients with SAB can be explained by baseline condition of patients. MRSA or inappropriate empiric therapy did not explain the increase in mortality. The patients afflicted with SAB changed over time. Epidemiology and outcomes of SAB vary with time and according to geographical location. External validity of studies should be taken into consideration.

Introduction: The emergence of antibiotic-resistant bacteria has driven renewed interest in older antibacterials, including colistin. Previous studies have shown that colistin is less effective and more toxic than modern antibiotics. In vitro synergy studies and clinical observational studies suggest a benefit of combining colistin with a carbapenem. A randomised controlled study is necessary for clarification., Methods and Analysis: This is a multicentre, investigator-initiated, open-label, randomised controlled superiority 1:1 study comparing colistin monotherapy with colistin-meropenem combination therapy for infections caused by carbapenem-resistant Gram-negative bacteria. The study is being conducted in 6 centres in 3 countries (Italy, Greece and Israel). We include patients with hospital-associated and ventilator-associated pneumonia, bloodstream infections and urosepsis. The primary outcome is treatment success at day 14, defined as survival, haemodynamic stability, stable or improved respiratory status for patients with pneumonia, microbiological cure for patients with bacteraemia and stability or improvement of the Sequential Organ Failure Assessment (SOFA) score. Secondary outcomes include 14-day and 28-day mortality as well as other clinical end points and safety outcomes. A sample size of 360 patients was calculated on the basis of an absolute improvement in clinical success of 15% with combination therapy. Outcomes will be assessed by intention to treat. Serum colistin samples are obtained from all patients to obtain population pharmacokinetic models. Microbiological sampling includes weekly surveillance samples with analysis of resistance mechanisms and synergy. An observational trial is evaluating patients who met eligibility requirements but were not randomised in order to assess generalisability of findings., Ethics and Dissemination: The study was approved by ethics committees at each centre and informed consent will be obtained for all patients. The trial is being performed under the auspices of an independent data and safety monitoring committee and is included in a broad dissemination strategy regarding revival of old antibiotics., Trial Registration Number: NCT01732250 and 2012-004819-31; Pre-results., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Bloodstream infections (BSIs) are both common and fatal in older patients. We describe data from studies evaluating older patients hospitalized with BSIs. Most older patients with BSIs present "typically" with either fever or leukocytosis. The most common source of BSI in older patients is the urinary tract, and accordingly, Gram-negative organisms predominate. A significant part of these BSIs may thus be preventable by removal of unnecessary urinary catheters. Increased long term mortality is reported following BSIs in older patients, however, data on other long-term outcomes, including functional capacity, cognitive decline and others are lacking. Management of BSIs may include less invasive procedures due to the fragility of older patients. This approach may delay the diagnosis and treatment in some cases. Older patients are probably under-represented in clinical trials assessing treatment of bacteremia. Physicians treating older patients should consider the relevance of these studies' outcomes.

Background: Prevention of catheter-related bloodstream infections in patients undergoing hemodialysis by use of antimicrobial catheter lock solutions has been examined in several trials, but no consensus is available for clinical practice., Methods: A systematic review and meta-analysis were performed of randomized controlled trials that compared single or combination antimicrobial catheter lock solutions with heparin or another antimicrobial for the prevention of infections in patients undergoing hemodialysis. The primary outcomes assessed were bloodstream infections, catheter-related bloodstream infections, and the need for catheter removal. Relative risks with 95% confidence intervals (CIs) for individual trials were pooled., Results: Eleven trials (924 patients) that assessed antibiotic catheter lock solutions and 5 trials (661 patients)that assessed non antibiotic antimicrobial catheter lock solutions met inclusion criteria. None of the trials assessed all bloodstream infections. Antibiotic catheter lock solutions significantly reduced catheter-related bloodstream infections (relative risk, 0.44; 95% CI, 0.38-0.50). Significant heterogeneity for this outcome could be explained by smaller effect estimates in larger trials that reported adequate randomization methods (relative risk, 0.60; 95%CI, 0.54-0.67). Efficacy was higher when additional preventive measures were used and to prevent the first episode of catheter-related bloodstream infection. Catheter removal rates were significantly reduced (relative risk, 0.35;95% CI, 0.23-0.55). Resistance development was documented in a single patient. Data concerning nonantibiotic antimicrobial lock solutions were limited and heterogeneous. High-quality trials that used additional preventive measures showed a significant reduction in catheter-related bloodstream infections (relative risk, 0.25; 95% CI,0.13-0.50)., Conclusions: Antibiotic catheter lock solutions reduce catheter-related bloodstream infections, with a number needed to treat of 4 patients (95% CI, 4-5), and catheter removal rates in patients undergoing hemodialysis. The use of antibiotic catheter lock solutions should be considered in routine clinical practice in conjunction with other prevention modalities.

Background: Prediction of bloodstream infection at the time of sepsis onset allows one to make appropriate and economical management decisions., Methods: The TREAT computerized decision-support system uses a causal probabilistic network, which is locally calibrated, to predict cases of bacteremia. We assessed the system's performance in 2 independent cohorts that included patients with suspected sepsis. Both studies were conducted in Israel, Italy, and Germany. Data were collected prospectively and were entered into the TREAT system at the time that blood samples were obtained for culture. Discriminative power was assessed using a receiver-operating characteristics curve., Results: In the first cohort, 790 patients were included. The area under the receiver-operating characteristics curve for prediction of bacteremia using the TREAT system was 0.68 (95% confidence interval [CI], 0.63-0.73). We used TREAT's prediction values to draw thresholds defining a low-, intermediate-, and high-risk groups for bacteremia, in which 3 (2.4%) of 123, 62 (12.8%) of 483, and 55 (29.9%) of 184 patients were bacteremic, respectively. In the second cohort, 1724 patients were included. The area under the receiver-operating characteristics curve was 0.70 (95% CI, 0.67-0.73). The prevalence of bacteremia observed in the low-, intermediate-, and high-risk groups defined by the first cohort were 1.3% (4 of 300 patients), 13.2% (150 of 1139 patients), and 28.1% (80 of 285 patients), respectively. The low-risk groups in the 2 cohorts comprised 15%-17% of all patients. Performance was stable in the 3 sites., Conclusions: Using variables available at the time that blood cultures were performed, the TREAT system successfully stratified patients on the basis of the risk for bacteremia. The system's predictions were stable in 3 locations. The TREAT system can define a low-risk group of inpatients with suspected sepsis for whom blood cultures may not be needed.

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]

Carbapenem resistant Acinetobacter baumannii (CRAB) is a significant cause of hospital acquired bloodstream infections in patients with hematological malignancies. Data regarding outcomes in this group of patients are limited. We retrospectively analyzed mortality risk factors of hospitalized hematological patients with CRAB bacteremia in our center. Among 46 included patients, overall 7-day mortality was 72% (33/46). Risk factors for 7-day mortality in multivariate analysis were higher infection severity score (SOFA score) at presentation (OR 1.481, 95% CI 1.091–2.012, p =.012) while appropriate antibiotic therapy within 48 h was protective (OR 0.052, 95% CI 0.005–0.590, p =.017). Inappropriate antibiotic therapy within 24 h was not significantly associated with 7-day mortality nor was absolute neutrophil count. Thirty-day mortality was 96% (44/46). CRAB bacteremia in hematological patients is associated with extremely high mortality, regardless of therapy. Infection control measures and antimicrobial stewardship aiming to prevent this infection of dismal prognosis are of major importance. [ABSTRACT FROM AUTHOR]

Introduction: Current guidelines recommend maintaining vancomycin trough concentrations between 15–20 mg/L for serious methicillin resistant staphylococcus aureus (MRSA) infections. This recommendation is based on limited evidence. Methods: A retrospective study including patients with vancomycin susceptible MRSA infections (MIC< = 2 mg/L), treated with vancomycin. We compared outcomes among patients attaining high (> = 15mg/L) vs low (<15mg/L) trough vancomycin levels. We used a propensity score to matching patients achieving low and high levels and conducted an adjusted analysis in the propensity score (PS)-matched cohort using regression analysis. Primary outcome was 30-day all-cause mortality. Results: Among 285 patients included, there were no significant differences between patients achieving high and low vancomycin levels in mortality (46/131, 35.1% vs 41/154, 26.6%), clinical success, microbiological success, or nephrotoxicity. Similarly, in the PS-matched cohort (n = 162), there was no significant difference in mortality between patients with high and low vancomycin levels (24/53, 45.3% vs 57/109, 52.3%, respectively), adjusted odds ratio for mortality with high levels 0.63 (95% confidence interval 0.28–1.43). In both cohorts, patients with pneumonia achieving high levels had significantly higher clinical and microbiological success (PS-matched cohort: clinical success: 16/32, 50.0% vs 5/27, 18.5%, p = 0.012; microbiological success: 19/32, 59.4% vs 7/27, 25.9%, p = 0.010), without significant differences in mortality. Conclusions: We found no association between vancomycin levels > = 15 mg/L and clinical outcomes in patients with MRSA infections. In patients with MRSA pneumonia, vancomycin levels > = 15 mg/L were associated with higher clinical success rates. Further larger cohort studies are needed to define optimal vancomycin levels according to the site of infection. [ABSTRACT FROM AUTHOR]

Introduction: Chills are a complication of patients undergoing hemodialysis. The rate of infection among hemodialysis patients presenting with chills is not well established, and empirical broad-spectrum antibiotics are usually the rule.Methods: We performed a retrospective study aiming to assess the rates of infection and bacteremia in hemodialysis patients presenting with chills. We evaluated risk factors for infection and bacteremia and tested a prediction model for infection.Results: Overall, 269 hemodialysis patients with a first episode of chills were included. Ninety patients (33.5%) had bacteremia and 162 (60.2%) had an infection. Risk factors for bacteremia in multivariate analysis included fever (odds ratio [OR] 1.6; 95% confidence interval [CI], 1.1-2.3; P = .009) and vascular catheter as dialysis access (OR 6.2; 95% CI, 3.2-12.0, P <.001). Leukocytosis was an additional risk factor in multivariate analysis for any type of infection (OR 1.265; 95% CI, 1.113-1.438; P <.001). Using a prediction model to evaluate patients without obvious source of infection, we found that patients with fistula or graft as their access, without fever, abnormal leukocytes, or hypoalbuminemia, had a low rate (1/17, 6%) of bacteremia.Conclusions: Hemodialysis patients presenting with chills during dialysis, with or without fever, have high rates (∼60%) of infection. Patients with no obvious source of infection, with fistula or graft as access, presenting without fever, leukocytosis, or hypoalbuminemia have low risk for bacteremia and may be investigated without prompt antibiotic treatment. All other patients should receive antibiotic coverage immediately following a chills episode. [ABSTRACT FROM AUTHOR]