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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.)

Introduction: The effect of remdesivir on COVID-19 mortality remains conflicting. Elderly individuals are at risk for poor COVID-19 outcomes. We aimed to assess the effect of remdesivir on COVID-19 mortality among elderly individuals, using real-world data., Methods: Retrospective multinational cohort of individuals aged ≥65 years, hospitalized with COVID-19 in six medical centres between January 2020 and May 2021. Associations with in-hospital mortality were evaluated using a multivariable logistic regression model with propensity score adjustment for remdesivir therapy and while implementing generalized estimating equations to control for centre effect. Sensitivity analysis was performed by stratification according to the degree of respiratory support., Results: Of 3010 individuals included, 2788 individuals required either oxygen supplementation or non-invasive/invasive mechanical ventilation, 489 (16%) were treated with remdesivir, and 836 (28%) died. Median age was 77 (IQR 70-84) years and 42% were women. Remdesivir was the only therapeutic intervention associated with decreased mortality [adjusted OR (aOR) 0.49, 95% CI 0.37-0.66, P < 0.001]. This protective effect was shown for individuals requiring oxygen support and non-invasive mechanical ventilation, while no association was found among individuals necessitating invasive mechanical ventilation.Risk factors for mortality included invasive ventilation (aOR 5.18, 95% CI 2.46-10.91, P < 0.001), higher serum creatinine (aOR 1.25, 95% CI 1.09-1.43, P = 0.001) and dyspnoea (aOR 1.40, 95% CI 1.07-1.84, P = 0.015) on presentation, and other non-modifiable factors, such as comorbidities., Conclusions: Among elderly individuals hospitalized with COVID-19, remdesivir carries survival benefit for those with moderate to severe disease. Its role among individuals with critical illness should be further assessed., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Recruitment of patients with critical priority antimicrobial-resistant (AMR) bacteria into drug approval randomized controlled trials (RCTs) has not been successful to date. Approaching from the viewpoint of clinician-investigators and learning from the experience of AMR-focused investigator-initiated trials, we present suggestions to improve feasibility and efficiency of RCTs evaluating patients with severe infections caused by carbapenem-resistant Gram-negative or other AMR bacteria. Considerations address the trials' eligibility criteria, whether the focus of the trial is pathogen- or syndrome-targeted, trials' case report forms and monitoring, informed consent strategies for the recruitment of extremely ill patients, team dedication and incentives to run the trial and alternative trial designs. Evidence on the effects of new drugs against the AMR that these drugs target is weak and needs to be improved through better industry-academic collaboration, taking advantage of the different strengths of industry-led and investigator-initiated research., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)

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.)

Background: Fatigue is the most prevalent and debilitating long-COVID (coronavirus disease) symptom; however, risk factors and pathophysiology of this condition remain unknown. We assessed risk factors for long-COVID fatigue and explored its possible pathophysiology., Methods: This was a nested case-control study in a COVID recovery clinic. Individuals with (cases) and without (controls) significant fatigue were included. We performed a multidimensional assessment evaluating various parameters, including pulmonary function tests and cardiopulmonary exercise testing, and implemented multivariable logistic regression to assess risk factors for significant long-COVID fatigue., Results: A total of 141 individuals were included. The mean age was 47 (SD: 13) years; 115 (82%) were recovering from mild coronavirus disease 2019 (COVID-19). Mean time for evaluation was 8 months following COVID-19. Sixty-six (47%) individuals were classified with significant long-COVID fatigue. They had a significantly higher number of children, lower proportion of hypothyroidism, higher proportion of sore throat during acute illness, higher proportions of long-COVID symptoms, and of physical limitation in daily activities. Individuals with long-COVID fatigue also had poorer sleep quality and higher degree of depression. They had significantly lower heart rate [153.52 (22.64) vs 163.52 (18.53); P = .038] and oxygen consumption per kilogram [27.69 (7.52) vs 30.71 (7.52); P = .036] at peak exercise. The 2 independent risk factors for fatigue identified in multivariable analysis were peak exercise heart rate (OR: .79 per 10 beats/minute; 95% CI: .65-.96; P = .019) and long-COVID memory impairment (OR: 3.76; 95% CI: 1.57-9.01; P = .003)., Conclusions: Long-COVID fatigue may be related to autonomic dysfunction, impaired cognition, and decreased mood. This may suggest a limbic-vagal pathophysiology., Clinical Trials Registration: NCT04851561., Competing Interests: Potential conflicts of interest. The authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: Limited data are available to guide colistin use in older adults (>65 years old). We aimed to assess the effectiveness and safety of colistin in this population., Methods: Systematic review and meta-analysis of original data from randomized control trials, cohort studies and case-control studies assessing colistin regimens with various comparisons for any infection. Original data were obtained from corresponding authors of original studies. The primary outcome was all-cause 1 month mortality; secondary outcomes included clinical and microbiological outcomes and adverse events, including acute kidney injury. Two independent reviewers screened citations, extracted data and assessed risk of bias. ORs with 95% CIs were pooled., Results: We included 38 publications (41 comparisons) reporting 2857 elderly individuals: 29 studies compared a colistin-based regimen versus another regimen (comparison 1) and 10 compared colistin monotherapy versus colistin combination (comparison 2). No significant difference in 1 month mortality was demonstrated between colistin and comparator (comparison 1, OR 1.13, 95% CI 0.80-1.60; comparison 2, OR 0.99, 95% CI 0.78-1.27). Clinical failure was significantly more likely with colistin-based therapy versus comparator (OR 1.52, 95% CI 1.13-2.06). Acute kidney injury was also significantly more common with colistin-based combinations versus other drugs (OR 3.81, 95% CI 2.14-6.77)., Conclusions: For older adults, colistin-based therapy resulted in no mortality difference, compared with other regimens, for any infection. Clinical failure and acute kidney injury were significantly more common with colistin-based regimens. Close renal function monitoring is needed while using colistin in older adults., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Chronic kidney disease (CKD) is a risk factor for severe coronavirus disease 2019 (COVID-19). We aimed to evaluate the real-life effectiveness of the BNT162b2 messenger RNA vaccine for a range of outcomes in patients with CKD compared with matched controls., Methods: Data from Israel's largest healthcare organization were retrospectively used. Vaccinated CKD [estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m 2 ] and maintenance dialysis patients were matched to vaccinated controls without CKD (eGFR ≥60 ml/min/1.73 m 2 ) according to demographic and clinical characteristics. Study outcomes included documented infection with severe acute respiratory syndrome coronavirus 2, symptomatic infection, COVID-19-related hospitalization, severe disease and death. Vaccine effectiveness was estimated as the risk ratio (RR) at days 7-28 following the second vaccine dose, using the Kaplan-Meier estimator. Effectiveness measures were also evaluated separately for various stages of CKD., Results: There were 67 861 CKD patients not treated with dialysis, 2606 hemodialysis (HD) patients and 70 467 matched controls. The risk of severe disease {RR 1.84 [95% confidence interval (CI) 0.95-2.67]} and death [RR 2.00 (95% CI 0.99-5.20)] was increased in nondialysis CKD patients compared with controls without CKD following vaccination. For the subgroup of patients with eGFR <30 ml/min/1.73 m 2 , the risk of severe disease and death was increased compared with controls [RR 6.42 (95% CI 1.85-17.51) and RR 8.81 (95% CI 1.63-13.81), respectively]. The risks for all study outcomes were increased in HD patients compared with controls., Conclusion: Two doses of the BNT162b2 vaccine were found to be less efficient for patients with eGFR <30 ml/min/1.73 m 2 . Risk in HD patients is increased for all outcomes. These results suggest prioritizing patients with eGFR <30 ml/min/1.73 m 2 for booster shots, pre- and post-exposure prophylaxis and early COVID-19 therapy., (© The Author(s) 2022. Published by Oxford University Press on behalf of the ERA.)

Accumulating evidence from randomized controlled trials (RCTs) supports 7 days treatment for uncomplicated Gram-negative bacteraemia. However, some patient populations were not well represented in these RCTs, including critically ill patients, immunocompromised patients and those with MDR bacteria. In this debate document, we discuss the pros and cons for treating patients with Gram-negative bacteraemia with a 7 day antibiotic course. We surmise that the patients who were not well represented in the RCTs are probably those who have most to lose from the drawbacks of prolonged antibiotic courses, including adverse events, superinfections and resistance development. Treatment durations among these patients can be managed individually, with C-reactive protein or procalcitonin guidance or by clinical measures, and with care to discontinue antibiotics as soon as the patient recovers clinically from the infection., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)

Objectives: To describe the population genetics and antibiotic resistance gene distribution of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates causing infections in three Mediterranean countries., Methods: Isolates were collected during the 2013-17 AIDA clinical trial in six hospitals in Israel, Greece and Italy. WGS, bioinformatic characterization and antibiotic resistance profiling were performed., Results: In the 247 CRAB isolates characterized in this study, ST distribution varied by country: 29/31 (93.5%) Greek isolates, 34/41 (82.9%) Italian isolates and 70/175 (40.0%) Israeli isolates belonged to ST2. The identified ST2 isolates included eight distinct clades: 2C, 2D and 2H were significantly more common in Italy, while 2F was unique to Greece. The uncommon ST3 was not present among Greek isolates and constituted only 5/41 (12%) Italian isolates. On the other hand, it was much more common among Israeli isolates: 78/175 (44.6%) belonged to ST3. The vast majority of isolates, 240/247 (97.2%), were found to harbour acquired carbapenemases, primarily blaOXA-23. The chromosomal oxaAb (blaOXA-51-like) and ampC genes characteristic of this organism were also ubiquitous. Most (96.4%) ST3 isolates carried a broad-host-range plasmid IncP1α., Conclusions: The geographical differences in CRAB populations support the theory that clonal spread of CRAB leads to endemicity in hospitals and regions. The close association between antibiotic resistance genes and clades, and between plasmids and STs, suggest that de novo creation of MDR A. baumannii is rare. The clustering of antibiotic resistance genes and plasmids that is unique to each clade/ST, and nearly uniform within clades/STs, suggests that horizontal transmission is rare but crucial to the clade's/ST's success., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Data regarding immunogenicity of mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines among kidney transplant recipients in the months following vaccination are lacking. We aimed to investigate humoral immune response at 3-4 months post-vaccination among a cohort of kidney transplant recipients, compared with a control group of dialysis patients. Anti-spike antibodies were tested at 1 and 3-4 months after vaccination. Of 259 kidney transplant recipients tested at a median time of 110 days from second vaccine dose, 99 (38%) were seropositive, compared with 83% (101/122) of control patients. Younger age, better renal function and lower immunosuppression levels were associated with seropositivity. A total of 14% (13/94) of participants seropositive at 1 month became seronegative at follow-up and 11% (18/165) became seropositive. The latter were mainly individuals with higher antibody levels at 1 month. Antibody levels at 3-4 months were significantly reduced in both study groups, although the decline was more pronounced in the control group. Kidney transplant recipients present poor antibody response to mRNA SARS-CoV-2 vaccination, with only 38% seropositive at 3-4 months. Nevertheless, the decay in antibody response over time is modest, and some patients may present delayed response, reaching adequate antibody levels at 3-4 months. Low seropositivity rates in this group call for investigating other immunization strategies., (© The Author(s) 2022. Published by Oxford University Press on behalf of the ERA.)

Background: Patients colonized with carbapenem-resistant Enterobacteriaceae (CRE) are at higher risk of developing CRE infection after liver transplantation (LT), with associated high morbidity and mortality. Prediction model for CRE infection after LT among carriers could be useful to target preventive strategies., Methods: Multinational multicenter cohort study of consecutive adult patients underwent LT and colonized with CRE before or after LT, from January 2010 to December 2017. Risk factors for CRE infection were analyzed by univariate analysis and by Fine-Gray subdistribution hazard model, with death as competing event. A nomogram to predict 30- and 60-day CRE infection risk was created., Results: A total of 840 LT recipients found to be colonized with CRE before (n = 203) or after (n = 637) LT were enrolled. CRE infection was diagnosed in 250 (29.7%) patients within 19 (interquartile range [IQR], 9-42) days after LT. Pre- and post-LT colonization, multisite post-LT colonization, prolonged mechanical ventilation, acute renal injury, and surgical reintervention were retained in the prediction model. Median 30- and 60-day predicted risk was 15% (IQR, 11-24) and 21% (IQR, 15-33), respectively. Discrimination and prediction accuracy for CRE infection was acceptable on derivation (area under the curve [AUC], 74.6; Brier index, 16.3) and bootstrapped validation dataset (AUC, 73.9; Brier index, 16.6). Decision-curve analysis suggested net benefit of model-directed intervention over default strategies (treat all, treat none) when CRE infection probability exceeded 10%. The risk prediction model is freely available as mobile application at https://idbologna.shinyapps.io/CREPostOLTPredictionModel/., Conclusions: Our clinical prediction tool could enable better targeting interventions for CRE infection after transplant., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Objectives: To assess whether results of observational studies of potential anti-COVID-19 drugs were reproduced in subsequent randomized controlled trials (RCTs)., Methods: This was a retrospective cross-sectional study, including studies published online between 1 January and 27 October 2020 that evaluated potential COVID-19 treatments and reported all-cause mortality., Results: Of 133 comparisons included in 117 studies, most were non-randomized (104/133, 78%). Hydroxychloroquine was the most common drug type, combined with azithromycin (n = 27, 20%) or alone (n = 22, 16%), followed by IL-6 inhibitors (n = 36, 27%) and corticosteroids (n = 26, 20%). Seventy-one percent (74/104) of non-randomized studies reported adjusted survival results and only 8% (8/104) adjusted for immortal time bias. Only two RCTs (2/29, 7%) reported significant survival benefit, both reporting treatment with corticosteroids, while 32/104 (31%) non-randomized studies showed statistically significant survival benefit associated with the intervention arm. The results of the majority (28/32, 88%) of non-randomized studies reporting survival benefit were not replicated by large-scale RCTs., Conclusions: The results of most non-randomized studies reporting survival benefit of potential anti-COVID-19 drugs were not replicated by large RCTs. Regulators and healthcare professionals should exercise caution and resist the pressure to approve and prescribe drugs of unproven efficacy and potential toxicity to optimize patient care and maintain public trust in medical science., (© 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.)

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.)

Background: Infections caused by multidrug-resistant (MDR) bacteria are a major public health threat. We aimed to assess the data supporting US Food and Drug Administration (FDA) approval of new agents aimed to treat MDR bacterial infections and the data provided by postmarketing studies., Methods: We identified all drugs with in vitro activity against MDR bacteria initially approved by the FDA between January 2010 and December 2018. Characteristics of trials supporting approval and regulatory pathways were collected from Drugs@FDA. Characteristics of postmarketing studies were extracted from drug labels and ClinicalTrials.gov entries effective 1 June 2019., Results: Initial approval of 11 newly approved antibiotics with anti-MDR activity was supported by 20 trials, all with noninferiority design. All initially approved indications were for common infections, mostly acute bacterial skin and skin-structure infections, regardless of causative microorganism. The proportion of MDR bacteria in most trials was low (<10% for gram-negative infections, <1% for gram-positive pneumonia). Most trials (90%) excluded immunocompromised and critically ill patients. Of 16 additional postmarketing randomized controlled trials identified through ClinicalTrials.gov, only 2 exclusively included infections caused by MDR bacteria, comprising 116 patients. No drug was granted accelerated approval, which would mandate postmarketing efficacy studies., Conclusions: The approval of new drugs with potential clinical activity against MDR bacteria is supported by trials evaluating infections caused by non-MDR organisms, using noninferiority design and excluding the patients most likely to require these agents. Subsequent postmarketing efficacy data against these organisms are scarce. Healthcare professionals and regulators should demand more robust data to support clinical decision making., (© 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: We evaluated whether carbapenem-colistin combination therapy reduces the emergence of colistin resistance, compared to colistin monotherapy, when given to patients with infections due to carbapenem-resistant Gram-negative organisms., Methods: This is a pre-planned analysis of a secondary outcome from a randomized, controlled trial comparing colistin monotherapy with colistin-meropenem combination for the treatment of severe infections caused by carbapenem-resistant, colistin-susceptible Gram-negative bacteria. We evaluated rectal swabs taken on Day 7 or later for the presence of new colistin-resistant (ColR) isolates. We evaluated the emergence of any ColR isolate and the emergence of ColR Enterobacteriaceae (ColR-E)., Results: Data were available for 214 patients for the primary analysis; emergent ColR organisms were detected in 22 (10.3%). No difference was observed between patients randomized to treatment with colistin monotherapy (10/106, 9.4%) versus patients randomized to colistin-meropenem combination therapy (12/108, 11.1%; P = .669). ColR-E organisms were detected in 18/249 (7.2%) patients available for analysis. No difference was observed between the 2 treatment arms (colistin monotherapy 6/128 [4.7%] vs combination therapy 12/121 [9.9%]; P = .111). Enterobacteriaceae, as the index isolate, was found to be associated with development of ColR-E (hazard ratio, 3.875; 95% confidence interval, 1.475-10.184; P = .006)., Conclusions: Carbapenem-colistin combination therapy did not reduce the incidence of colistin resistance emergence in patients with infections due to carbapenem-resistant organisms. Further studies are necessary to elucidate the development of colistin resistance and methods for its prevention., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Aims: The dual antiplatelet therapy (DAPT) score is meant to aid clinicians choose the DAPT duration but attempts to examine the external validity of the DAPT score and its decision tool have reported mostly disappointing results. Our aim was to perform a meta-analysis of all available data on the external validity of the DAPT score., Methods and Results: We conducted a meta-analysis of studies that examined the external validity of the DAPT score/its decision tool. Seven studies (77 274 patients) were included. Follow-up ranged from 6 to 24 (median 18) months. Overall, high (≥2) DAPT score was associated with increased risk for myocardial infarction (MI)/stent thrombosis (ST) [odds ratio (OR) 1.54, 95% confidence interval (CI) 1.41-1.69; P < 0.01], and lower risk for bleeding (OR 0.84, 95% CI 0.73-0.97; P = 0.01). In the high DAPT score stratum, extended (12-24 months), as compared to standard (6-12 months) DAPT duration was associated with a reduction in the risk for MI/ST (OR 0.67, 95% CI 0.48-0.94; P = 0.02), and no difference in the risk for bleeding (OR 1.04, 95% CI 0.65-1.66; P = 0.88), while in the low DAPT score stratum, extended DAPT duration was associated with no difference in the risk for MI/ST (OR 1.04, 95% CI 0.76-1.43; P = 0.80), and an increased risk for bleeding (OR 1.58, 95% CI 1.15-2.15; P < 0.01)., Conclusions: This first meta-analysis of studies examining the external validation of the DAPT score and its decision tool, our results suggest that the DAPT score is useful both for stratifying post-percutaneous coronary intervention patients into risk strata for future ischaemic and bleeding events as well aiding in choosing the optimal DAPT duration for the individual patient., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background: The optimal antibiotic regimen for Pseudomonas aeruginosa bacteremia is controversial. Although β-lactam monotherapy is common, data to guide the choice between antibiotics are scarce. We aimed to compare ceftazidime, carbapenems, and piperacillin-tazobactam as definitive monotherapy., Methods: A multinational retrospective study (9 countries, 25 centers) including 767 hospitalized patients with P. aeruginosa bacteremia treated with β-lactam monotherapy during 2009-2015. The primary outcome was 30-day all-cause mortality. Univariate and multivariate, including propensity-adjusted, analyses were conducted introducing monotherapy type as an independent variable., Results: Thirty-day mortality was 37/213 (17.4%), 42/210 (20%), and 55/344 (16%) in the ceftazidime, carbapenem, and piperacillin-tazobactam groups, respectively. Type of monotherapy was not significantly associated with mortality in either univariate, multivariate, or propensity-adjusted analyses (odds ratio [OR], 1.14; 95% confidence interval [CI], 0.52-2.46, for ceftazidime; OR, 1.3; 95% CI, 0.67-2.51, for piperacillin-tazobactam, with carbapenems as reference in propensity adjusted multivariate analysis; 542 patients). No significant difference between antibiotics was demonstrated for clinical failure, microbiological failure, or adverse events. Isolation of P. aeruginosa with new resistance to antipseudomonal drugs was significantly more frequent with carbapenems (36/206 [17.5%]) versus ceftazidime (25/201 [12.4%]) and piperacillin-tazobactam (28/332 [8.4%] (P = .007)., Conclusions: No significant difference in mortality, clinical, and microbiological outcomes or adverse events was demonstrated between ceftazidime, carbapenems, and piperacillin-tazobactam as definitive treatment of P. aeruginosa bacteremia. Higher rates of resistant P. aeruginosa after patients were treated with carbapenems, along with the general preference for carbapenem-sparing regimens, suggests using ceftazidime or piperacillin-tazobactam for treating susceptible infection., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: little is known on the clinical implications of vancomycin trough levels among older patients., Objective: to evaluate the association between vancomycin levels and outcomes among older versus younger patients., Design: retrospective study., Subjects: patients aged 18-64 and ≥65 years treated with vancomycin for documented methicillin resistant Staphylococcus aureus (MRSA) infections., Methods: we compared the effectiveness and toxicity of vancomycin according to trough levels in older versus younger patients. Subgroup analysis of patients with glomerular filtration rate (GFR) > 60 ml/min/1.73 m2 was performed., Results: we included 181 patients aged ≥65 years and 104 younger patients. Mean age in the older group was 76.9 ± 8 years versus 50.9 ± 12.4 in the younger group. Vancomycin trough levels and 24-hours area under the curve to minimal inhibitory concentrations (AUC/MIC) were significantly higher in older patients who were also significantly more likely to achieve trough levels of ≥15 mg/l within 4 days, (98/181 (54.1%) vs. 38/104 (36.5%) in younger patients, P = 0.004). Results were similar among patients with GFR > 60. Thirty-day mortality was significantly higher in older (74/181, 40.9% vs. 13/104, 12.5%, respectively, P < 0.001). There was no association between vancomycin trough levels and mortality among older patients. No significant differences were demonstrated in clinical or microbiological success or nephrotoxicity., Conclusions: applying uniform dosing recommendations across age groups among adults with MRSA infections results in higher vancomycin levels and AUC/MIC in older versus younger patients. Yet, mortality rates remain higher among older adults. Prospective studies are needed to define the optimal approach for using this drug in older patients., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

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: We evaluated the association between mortality and colistin resistance in Acinetobacter baumannii infections and the interaction with antibiotic therapy., Methods: This is a secondary analysis of a randomized controlled trial of patients with carbapenem-resistant gram-negative bacterial infections treated with colistin or colistin-meropenem combination. We evaluated patients with infection caused by carbapenem-resistant A. baumannii (CRAB) identified as colistin susceptible (CoS) at the time of treatment and compared patients in which the isolate was confirmed as CoS with those whose isolates were retrospectively identified as colistin resistant (CoR) when tested by broth microdilution (BMD). The primary outcome was 28-day mortality., Results: Data were available for 266 patients (214 CoS and 52 CoR isolates). Patients with CoR isolates had higher baseline functional capacity and lower rates of mechanical ventilation than patients with CoS isolates. All-cause 28-day mortality was 42.3% (22/52) among patients with CoR strains and 52.8% (113/214) among patients with CoS isolates (P = .174). After adjusting for variables associated with mortality, the mortality rate was lower among patients with CoR isolates (odds ratio [OR], 0.285 [95% confidence interval {CI}, .118-.686]). This difference was associated with treatment arm: Mortality rates among patients with CoR isolates were higher in those randomized to colistin-meropenem combination therapy compared to colistin monotherapy (OR, 3.065 [95% CI, 1.021-9.202])., Conclusions: Colistin resistance determined by BMD was associated with lower mortality among patients with severe CRAB infections. Among patients with CoR isolates, colistin monotherapy was associated with a better outcome compared to colistin-meropenem combination therapy., Clinical Trials Registration: NCT01732250., (© 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: 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.)

Background: Empirical colistin should be avoided. We aimed to evaluate the association between covering empirical antibiotics (EAT) and mortality for infections caused by carbapenem-resistant gram-negative bacteria (CRGNB)., Methods: This was a secondary analysis of a randomized controlled trial, including adults with bloodstream infections, pneumonia, or urosepsis caused by CRGNB. All patients received EAT followed by covering targeted therapy. The exposure variable was covering EAT in the first 48 hours. The outcome was 28-day mortality. We adjusted the analyses by multivariable regression analysis and propensity score matching., Results: The study included 406 inpatients with severe CRGNB infections, mostly Acinetobacter baumannii (312/406 [77%]). Covering EAT was given to 209 (51.5%) patients, mostly colistin (n = 200). Patients receiving noncovering EAT were older, more frequently unconscious and dependent, carrying catheters, and mechanically ventilated with pneumonia. Mortality was 84 of 197 (42.6%) with noncovering vs 96 of 209 (45.9%) with covering EAT (P = .504). Covering EAT was not associated with survival in the adjusted analysis; rather, there was a weak association with mortality (odds ratio [OR], 1.37; 95% confidence interval [CI], 1.02-1.84). Results were similar for colistin monotherapy and colistin-carbapenem combination EAT. In the propensity score-matched cohort (n = 338) covering antibiotics were not significantly associated with mortality (OR, 1.42; 95% CI, .91-2.22). Similar results were obtained in an analysis of 14-day mortality., Conclusions: Empirical use of colistin before pathogen identification, with or without a carbapenem, was not associated with survival following severe infections caused by CRGNBs, mainly A. baumannii.

Background: Ceftazidime/avibactam is approved for complicated intra-abdominal and urinary tract infections (UTIs) based on results from randomized controlled trials (RCTs). Data regarding its effectiveness in treating hospital-acquired infections or resistant pathogens have not been systematically compiled., Methods: A systematic review and meta-analysis including RCTs evaluating ceftazidime/avibactam versus comparator for the treatment of any infection. Primary outcome was 30 day all-cause mortality. Subgroups of hospital-acquired infections and specific resistance phenotypes were planned., Results: Seven publications (eight trials, 4093 patients) were included, reporting a baseline ∼25% of ESBL-carrying Enterobacteriaceae. No significant difference between ceftazidime/avibactam and comparator (mostly carbapenem) was demonstrated for 30 day all-cause mortality, late follow-up mortality and clinical response [relative risk (RR) 1.10, 95% CI 0.70-1.72, P = 0.69; RR 1.23, 95% CI 0.87-1.76, P = 0.25; RR 0.98, 95% CI 0.96-1.01, P = 0.21, respectively, without significant heterogeneity]. Higher microbiological response rate was demonstrated with ceftazidime/avibactam in patients with UTI (RR 1.14, 1.0-1.29, P = 0.05, I2 = 51%). No significant difference in clinical response was demonstrated for patients with ceftazidime-resistant pathogens (RR 1.02, 95% CI 0.94-1.10, P = 0.66, I2 = 0%). Results for other subgroups of resistant pathogens or hospital-acquired infection were not available. Serious adverse events (SAEs) were significantly more common with ceftazidime/avibactam (RR 1.24, 95% CI 1.00-1.54, P = 0.05, I2 = 0%)., Conclusions: Ceftazidime/avibactam is clinically and microbiologically as effective as carbapenems for treatment of infections in a setting of ∼25% ESBL-carrying Enterobacteriaceae. Safety of the drug should be further evaluated owing to a higher rate of SAEs compared with carbapenems. Further studies should assess the drug's effectiveness in the treatment of carbapenemase-producing Enterobacteriaceae.

Background: Little is known about Plasmodium malariae, a relatively rare cause of malaria in returned travelers. Recently, polymerase chain reaction (PCR) use for malaria diagnosis has enhanced specificity of P. malariae detection. The study objective was to describe the unique aspects of P. malariae diagnosis and clinical course in travelers., Methods: Malaria is a reportable disease in Israel. All PCR-proven P. malariae monoinfections in Israeli travelers between January 2008 and January 2017 were retrieved from the Ministry of Health Reference Parasitology Laboratory. Data regarding method and timing of diagnosis, clinical characteristics, and laboratory testing were collected from patient charts., Results: Eighteen patients with P. malariae were included. All cases were acquired in Africa. During the study period, the relative proportion of P. malariae increased (2%-10% of all malaria cases). Malaria was identified by blood smear in 10 of 18 patients (56%) on admission, and by rapid antigen test in 5 of 18 (29%) patients only, while P. malariae speciation was correctly identified by smear in 2 of 18 (11%) patients. Though all patients reported fever, only 4 of 18 (22%) described a quartan fever course. In 7 of 18 (39%) patients, malaria was contracted despite prophylactic treatment. Five patients had prolonged prepatent periods (median, 55 days), all of whom received prior prophylaxis., Conclusions: The relative proportion of P. malariae is on the rise. Diagnosis in routine clinical settings is inadequate due to the low sensitivity and specificity of blood smears. PCR should be considered when clinical suspicion is high. Prophylaxis failure, which caused delayed clinical presentation, was documented., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background:  Optimizing colistin dosing should translate to improved patient outcomes., Methods:  We used data from 2 prospective cohort studies performed between 2006 and 2009 and between 2012 and 2015. In the latter period, a new policy of high-dose colistin (9 million international units [MIU] loading dose followed by 9 MIU daily for normal renal function) was introduced in 2 participating hospitals. We included adult inpatients with invasive infections caused by carbapenem-resistant gram-negative bacteria treated with colistin. Our primary exposure variable was colistin dose, dichotomized to high-dose vs other regimens. The primary outcome was 28-day mortality. We generated a propensity score for high-dose colistin and conducted propensity-adjusted multivariable and matched-cohort analyses for mortality., Results:  Of 529 consecutive patients fulfilling inclusion criteria, 144 were treated with high-dose colistin and 385 with lower-dose colistin regimens. The median daily dose in the high-dose group was 9 MIU (interquartile range [IQR], 9-9) vs 4 MIU (IQR, 3-6) with other regimens. There were 50 of 144 (34.7%) deaths with high-dose colistin vs 165 of 385 (42.9%) with low-dose colistin (P = .1). The propensity-adjusted odds ratio (OR) for mortality was 1.07 (95% confidence interval [CI], .63-1.83) for high-dose colistin. Similar results were obtained when using the study period as the exposure variable, in the subgroup of bacteremic patients (n = 207) and in the propensity-matched cohort (OR, 1.11 [95% CI, .67-1.82]). Nephrotoxicity (RIFLE injury or higher; OR, 2.12 [95% CI, 1.29-3.48]; n = 396) and seizures were significantly more common with high-dose colistin., Conclusions:  In a large cohort, we found no association between high colistin dosing and all-cause mortality. High dosing was associated with more nephrotoxicity., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)

Antibiotics are among the most important interventions in healthcare. Resistance of bacteria to antibiotics threatens the effectiveness of treatment. Systematic reviews of antibiotic treatments often do not address resistance to antibiotics even when data are available in the original studies. This omission creates a skewed view, which emphasizes short-term efficacy and ignores the long-term consequences to the patient and other people. We offer a framework for addressing antibiotic resistance in systematic reviews. We suggest that the data on background resistance in the original trials should be reported and taken into account when interpreting results. Data on emergence of resistance (whether in the body reservoirs or in the bacteria causing infection) are important outcomes. Emergence of resistance should be taken into account when interpreting the evidence on antibiotic treatment in randomized controlled trials or systematic reviews., (© The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: Data on the relative efficacy of β-lactam/β-lactamase inhibitors (BL/BLIs) versus carbapenems are scant., Methods: This is a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing any BL/BLI versus any carbapenem for the treatment of sepsis. The primary outcome was all-cause mortality. A broad search was conducted with no restrictions on language, publication status or date. Two reviewers independently applied the inclusion criteria and extracted the data. Assessment of risk of bias was performed using the domain-based approach. Subgroup analyses were used to investigate heterogeneity and focus on patient groups more likely to harbour ESBL-positive bacteria. Risk ratios (RRs) with 95% CIs were calculated and pooled., Results: Thirty-one RCTs were included. There was no difference between BL/BLIs and carbapenems in terms of mortality (RR 0.98, 95% CI 0.79-1.20), without heterogeneity. No differences were observed with regard to clinical or microbiological failure and bacterial superinfections. The results were not affected by risk of bias. No differences were detected in the subgroups of patients with nosocomial infections, Gram-negative infections and neutropenic fever. Adverse events requiring discontinuation were more common with BL/BLIs, on account of an increased incidence of diarrhoea. However, Clostridium difficile-associated diarrhoea (RR 0.29, 95% CI 0.10-0.87) was more frequent with carbapenems and seizures were more frequent with imipenem (RR 0.21, 95% CI 0.05-0.93)., Conclusions: No differences in efficacy between BL/BLIs and carbapenems exist in RCTs including patient populations with a certain, albeit unknown, rate of ESBL-positive bacteria causing infections., (© The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: Acute pyelonephritis is a frequent cause of morbidity, with a wide variation in duration of therapy. We performed a systematic review of all randomized controlled trials (RCTs) comparing ≤7 days treatment with a longer course., Methods: Electronic databases were searched to identify RCTs that assessed adults treated for pyelonephritis, comparing a 7 day or shorter versus longer therapy. Primary outcome was clinical failure at the end of the long treatment arm (EOT). Secondary outcomes included clinical failure at the end of follow-up (EOF), microbiological failure, all-cause mortality, the development of resistance and adverse events., Results: Clinical failure at EOT did not significantly differ between the two treatment arms [relative risk (RR) 0.63, 95% CI 0.33-1.18, I(2) = 41%]. Results did not differ when including studies comparing only fluoroquinolones, reducing the heterogeneity (RR 0.76, 95% CI 0.49-1.17, I(2) = 0%). We found no difference between the short and long treatment arms regarding clinical failure at EOF, even in a small subgroup of bacteraemic patients. No difference was found between the arms regarding microbiological failure at EOF, except in a subgroup of studies with a high percentage of patients with urogenital abnormalities, where microbiological failure at EOF was significantly higher in the short treatment arm (RR 1.78, 95% CI 1.02-3.10, I(2) = 21%). Adverse events were similar between the arms., Conclusions: Seven days of treatment for acute pyelonephritis is equivalent to longer treatment in terms of clinical failure and microbiological failure, including in bacteraemic patients. In patients with urogenital abnormalities, the evidence, although weak, suggests that longer treatment is required.

Background: Tigecycline is a novel glycylcycline that exhibits broad-spectrum antibacterial activity. Recently, the US FDA issued a warning concerning increased mortality with tigecycline in randomized controlled trials (RCTs)., Methods: We conducted a systematic review and meta-analysis of RCTs that compared tigecycline with any other antibiotic regimen for the treatment of any infection. A comprehensive search, without publication status or other restrictions, was conducted. The primary outcome was overall 30 day mortality. The secondary outcome included clinical and microbiological failure, superinfections and adverse events (AEs). The trials' risks of bias and their effects on results were assessed. Two reviewers independently extracted the data. Individual trials' relative risks (RRs) were pooled using a fixed effect meta-analysis., Results: Fifteen trials (7654 patients) were included. Overall mortality was higher with tigecycline compared with other regimens [RR 1.29, 95% confidence interval (CI) 1.02-1.64, without heterogeneity]. The type of infection assessed and the trials' reported risks of bias did not affect this result. Clinical failure was significantly higher with tigecycline (RR 1.16, 95% CI 1.06-1.27) and non-statistically significant higher rates of microbiological failure were demonstrated (RR 1.13, 95% CI 0.99-1.30). Development of septic shock was significantly more frequent with tigecycline (RR 7.01, 95% CI 1.27-38.66). Superinfections were significantly more common with tigecycline and so were AEs, including all AEs and AEs requiring discontinuation., Conclusions: In the light of the increased mortality, probably explained by decreased clinical and microbiological efficacy, clinicians should avoid tigecycline monotherapy in the treatment of severe infections and reserve it as a last-resort drug.

Background: Colistin has re-entered clinical use by necessity. We aimed to assess its effectiveness and safety compared with newer antibiotics., Methods: This was a single-centre, prospective cohort study. Inclusion criteria were microbiologically documented pneumonia, urinary tract infection, surgical site infection, meningitis or bacteraemia treated appropriately with colistin versus imipenem, meropenem or ampicillin/sulbactam (comparators). All consecutive patients were included, only once, between May 2006 and July 2009. The primary outcome was 30 day mortality. Multivariable and Cox regression survival analyses were used to adjust comparisons between groups. Odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals are reported., Results: Two hundred patients treated with colistin and 295 patients treated with comparators were included. Treatment with colistin was associated with older age, admission from healthcare facilities, mechanical ventilation and lower rate of early appropriate antibiotic treatment. The 30 day mortality was 39% (78/200) for colistin versus 28.8% (85/295) for comparators; unadjusted OR 1.58 (1.08-2.31). In the adjusted analysis the OR was 1.44 (0.91-2.26) overall and 1.99 (1.06-3.77) for bacteraemic patients (n = 220). At the end of follow-up, treatment with colistin was significantly associated with cumulative mortality; adjusted HR 1.27 (1.01-1.60) overall and 1.65 (1.18-2.31) among patients with bacteraemia. Nephrotoxicity at the end of treatment was more frequent with colistin; OR adjusted for other risk factors for nephrotoxicity 3.31 (1.54-7.08). Treatment with colistin was followed by increased incidence of Proteus spp. infections during a 3 month follow-up., Conclusions: The need for colistin treatment is associated with poorer survival. Adjusted analyses suggest that colistin is less effective and more toxic than beta-lactam antibiotics.

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.

Objectives: Early, empirical broad-spectrum antibiotic treatment is the established practice for febrile neutropenia. Several beta-lactams are accepted for monotherapy. We asked whether patients' outcomes are influenced by the chosen beta-lactam., Methods: Systematic review and meta-analysis of randomized controlled trials comparing anti-pseudomonal beta-lactams administered as empirical monotherapy for febrile neutropenia, with or without vancomycin. The search included The Cochrane Library, PubMed, Embase, Lilacs databases, bibliography, conference proceedings, trial registries and FDA new drug approvals. Two reviewers independently applied selection criteria, performed quality assessment and extracted the data. Trials assessing the same beta-lactam were pooled using the fixed effect model. Relative risks (RRs) with 95% confidence intervals (CIs) were calculated. The primary outcome assessed was all-cause mortality., Results: Thirty-three trials fulfilled inclusion criteria. Cefepime was associated with higher all-cause mortality at 30 days than other beta-lactams (RR 1.44, 95% CI 1.06-1.94, 3123 participants). Carbapenems were associated with fewer treatment modifications, including addition of glycopeptides, than ceftazidime or other comparators. Adverse events were significantly more frequent with carbapenems, specifically pseudomembranous colitis (RR 1.94, 95% CI 1.24-3.04, 2025 participants). All-cause mortality was unaltered. Piperacillin/tazobactam was compared only with cefepime and carbapenems, in six trials. No significant differences were demonstrated with paucity of data for all-cause mortality., Conclusions: The use of cefepime for febrile neutropenia is associated with increased mortality and should be carefully considered pending further analysis. Empirical use of carbapenems entails fewer treatment modifications, but an increased rate of pseudomembranous colitis. Ceftazidime, piperacillin/tazobactam, imipenem/cilastatin and meropenem appear to be suitable agents for monotherapy.