A comprehensive, predictive mortality score for patients with bloodstream infections (PROBAC): a prospective, multicentre cohort study.

OBJECTIVES: Bloodstream infections (BSI) are an important cause of mortality, although they show heterogeneity depending on patients and aetiological factors. Comprehensive and specific mortality scores for BSI are scarce. The objective of this study was to develop a mortality predictive score in BSI based on a multicentre prospective cohort. METHODS: A prospective cohort including consecutive adults with bacteraemia recruited between October 2016 and March 2017 in 26 Spanish hospitals was randomly divided into a derivation cohort (DC) and a validation cohort (VC). The outcome was all-cause 30-day mortality. Predictors were assessed the day of blood culture growth. A logistic regression model and score were developed in the DC for mortality predictors; the model was applied to the VC. RESULTS: Overall, 4102 patients formed the DC and 2009 the VC. Mortality was 11.8% in the DC and 12.34% in the CV; the patients and aetiological features were similar for both cohorts. The mortality predictors selected in the final multivariate model in the DC were age, cancer, liver cirrhosis, fatal McCabe underlying condition, polymicrobial bacteraemia, high-risk aetiologies, high-risk source of infection, recent use of broad-spectrum antibiotics, stupor or coma, mean blood pressure <70 mmHg and PaO2/FiO2 ≤ 300 or equivalent. Mortality in the DC was <2% for ≤2 points, 6%-14% for 3-7 points, 26%-45% for 8-12 points and ≥60% for ≥13 points. The predictive score had areas under the receiving operating curves of 0.81 (95% CI 0.79-0.83) in the DC and 0.80 (0.78-0.83) in the VC. CONCLUSIONS: A 30 day mortality predictive score in BSI with good discrimination ability was developed and internally validated.

Clinical characteristics, predisposing factors and outcomes for Enterococcus faecalis versus Enterococcus faecium bloodstream infections: a prospective multicentre cohort study.

PURPOSES: Enterococcal BSI is associated with significant morbidity and mortality, with fatality rates of approximately 20-30%. There are microbiological and clinical differences between E. faecalis and E. faecium infections. The aim of this study was to investigate differences in predisposing factors for E. faecalis and E. faecium BSI and to explore prognostic factors. METHODS: This study was a post-hoc analysis of PROBAC, a Spanish prospective, multicenter, cohort in 2016-2017. Patients with E. faecalis or E. faecium BSI were eligible. Independent predictors for BSI development in polymicrobial and monomicrobial BSI and in-hospital mortality in the monomicrobial group were identified by logistic regression. RESULTS: A total of 431 patients were included. Independent factors associated with E. faecium BSI were previous use of penicillins (aOR 1.99 (95% CI 1.20-3.32)) or carbapenems (2.35 (1.12-4.93)), hospital-acquired BSI (2.58 (1.61-4.12)), and biliary tract source (3.36 (1.84-6.13)), while congestive heart failure (0.51 (0.27-0.97)), cerebrovascular disease (0.45 (0.21-0.98)), and urinary tract source (0.49 (0.26-0.92)) were associated with E. faecalis BSI. Independent prognostic factors for in-hospital mortality in E. faecalis BSI were Charlson Comorbidity Index (1.27 (1.08-1.51)), SOFA score (1.47 (1.24-1.73)), age (1.06 (1.02-1.10)), and urinary/biliary source (0.29 (0.09-0.90)). For E. faecium BSI, only SOFA score (1.34 (1.14-1.58) was associated with in-hospital mortality. CONCLUSIONS: The factors associated with E. faecium and E. faecalis BSI are different. These variables may be helpful in the suspicion of one or other species for empiric therapeutic decisions and provide valuable information on prognosis.

Differences in clinical outcomes of bloodstream infections caused by Klebsiella aerogenes, Klebsiella pneumoniae and Enterobacter cloacae: a multicentre cohort study.

BACKGROUND: Klebsiella aerogenes has been reclassified from Enterobacter to Klebsiella genus due to its phenotypic and genotypic similarities with Klebsiella pneumoniae. It is unclear if clinical outcomes are also more similar. This study aims to assess clinical outcomes of bloodstreams infections (BSI) caused by K. aerogenes, K. pneumoniae and Enterobacter cloacae, through secondary data analysis, nested in PRO-BAC cohort study. METHODS: Hospitalized patients between October 2016 and March 2017 with monomicrobial BSI due to K. aerogenes, K. pneumoniae or E. cloacae were included. Primary outcome was a composite clinical outcome including all-cause mortality or recurrence until 30 days follow-up. Secondary outcomes were fever ≥ 72 h, persistent bacteraemia, and secondary device infection. Multilevel mixed-effect Poisson regression was used to estimate the association between microorganisms and outcome. RESULTS: Overall, 29 K. aerogenes, 77 E. cloacae and 337 K. pneumoniae BSI episodes were included. Mortality or recurrence was less frequent in K. aerogenes (6.9%) than in E. cloacae (20.8%) or K. pneumoniae (19.0%), but statistical difference was not observed (rate ratio (RR) 0.35, 95% CI 0.08 to 1.55; RR 0.42, 95% CI 0.10 to 1.71, respectively). Fever ≥ 72 h and device infection were more common in K. aerogenes group. In the multivariate analysis, adjusted for confounders (age, sex, BSI source, hospital ward, Charlson score and active antibiotic therapy), the estimates and direction of effect were similar to crude results. CONCLUSIONS: Results suggest that BSI caused by K. aerogenes may have a better prognosis than E. cloacae or K. pneumoniae BSI.

Long-term effectiveness, safety, and tolerability of doravirine in antiretroviral-experienced people with HIV in real life.

Real-life data on doravirine (DOR) in different drug combinations are limited. We evaluated the effectiveness of DOR plus two nucleos(t)ide reverse transcriptase inhibitors (NRTI), mainly abacavir/lamivudine, and dual therapies in people with HIV (PWH), mostly virologically suppressed. Ambispective observational study that enrolled adults PWH who initiated a DOR-based regimen from September 2020 to February 2022 at a referral center in Spain. Participants were grouped as follows: A, received DOR plus two NRTI; B, dual therapy (DT) with DOR plus dolutegravir (DTG) or darunavir/cobicistat (DRVc); C, DOR plus ≥two antiretroviral drugs. The primary endpoints were treatment effectiveness at week 48 by intention-to-treat (ITT) and per-protocol analysis (OT). A cohort of 187 participants, 91% virologically suppressed, were analyzed after a median follow-up of 112 weeks (80-136). Group A received DOR plus abacavir/lamivudine (ABV/3TC) (n = 109) or tenofovir/emtricitabine (TFV/3TC) (n = 45). At week 48, the effectiveness of DOR plus ABV/3TC by ITT was 90.8% (CI95, 88.0-93.6), better than with TFV/FTC [73.3% (66.7-79.9); P = 0.003]. Only one virologic failure was observed. Mild adverse effects were the cause of treatment discontinuation in 7.8%, followed by switching to a single-tablet regimen. In group B, the effectiveness by ITT was 92.9% (CI95, 88.0-97.8) at week 48. No adverse effects or virologic failure were registered in this group. DOR plus two NRTI or DT have long-term effectiveness and safety as a switching option for PWH, mostly virologically suppressed. The DOR plus ABV/3TC combination has shown even better effectiveness than TFV/FTC.IMPORTANCEDOR-based regimens have shown long-term effectiveness and safety in PWH, mostly virologically suppressed. The combination of DOR plus ABV/3TC has shown even better safety and effectiveness than TFV/FTC. DOR plus two NRTI offers cost benefits compared to other regimens.

DOLAMA 200: Effectiveness and Safety of a Dual Therapy with Dolutegravir Plus Lamivudine in Treatment-Experienced HIV-1 Infected Real World Participants in Spain.

The continuous pharmacological advances in antiretroviral treatment (ART) and the increasing understanding of HIV drug resistance has led to a change in the paradigm of ART optimization in the setting of the viral suppression of treatment-experienced patients with the emerging evidence of the effectiveness and safety of dual therapies. The aim of this study is to determine the antiviral efficacy and safety of switching to Dolutegravir + Lamivudine in people living with HIV, and to analyze the rate of patients with virologic failure (VF). A total of 200 patients were included with a median age of 51 years, 189 cells/µL of nadir CD4+, 13 years on ART and four previous ART regimens. Among the 168 patients who completed a follow-up at 48 weeks, a total of five VFs occurred, resulting in a 2.98% (5/168) VF rate. The results of the intention-to-treat analysis were a VF rate of 2.54% (5/197), and the rate of patients/year with viral suppression was 98.3% (298/303) in the observed data analysis. We observed a significant improvement in mean CD4 lymphocytes, the CD4/CD8 ratio and lipid profiles. The optimization of ART to DTG plus 3TC is a cost-effective switch option for treatment-experienced HIV patients, and also improves their lipid profiles.

Mortality impact of further delays in active targeted antibiotic therapy in bacteraemic patients that did not receive initial active empiric treatment: Results from the prospective, multicentre cohort PROBAC.

OBJECTIVES: The early initiation of the empirical antibiotic treatment and its impact on mortality in patients with bacteraemia has been extensively studied. However, information on the impact of precocity of the targeted antibiotic treatment is scarce. We aimed to study the impact of further delay in active antibiotic therapy on 30-day mortality among patients with bloodstream infection who had not received appropriate empirical therapy. DESIGN: We worked with PROBAC cohort (prospective and compound by patients from 26 different Spanish hospitals). We selected a total of 1703 patients, who survived to day 2 without having received any active antibiotic therapy against the causative pathogen. RESULTS: The 30-day mortality was 14% (238 patients). The adjusted odds of mortality increased for every day of delay, from 1.53 (95% confidence interval (CI) 1.13-2.08) for day 3 or after to 11.38 (95% CI 7.95-16.38) for day 6 or after. CONCLUSION: We concluded that among patients who had not received active treatment within the first 2 days of blood culture collection, additional delays in active targeted therapy were associated with increased mortality. These results emphasize the importance of active interventions in the management of patients with bloodstream infections.

Long-term effects on immunological, inflammatory markers, and HIV-1 reservoir after switching to a two-drug versus maintaining a three-drug regimen based on integrase inhibitors.

Objective: To compare the long-term effects on immune parameters, inflammation, and HIV-1 reservoir after switching to a two-drug (2DR) versus maintaining an integrase inhibitor (InSTI)-based three-drug regimen (3DR). Methods: Cross-sectional study in which HIV-1 treatment-naïve people started and maintained an InSTI-based 3DR or, at different times, switched to 2DR (dolutegravir or darunavir/cobicistat + lamivudine). CD4+ and CD8+ T-cell activation and exhaustion, plasma concentrations of hs-CRP, D-dimer, P-selectin, IL-1ß, IL-6, TNF-α, IFN-γ, IP-10, sTNFR-I/II, MIP-1α/ß, I-FABP, LBP, sCD14, sCD163, MCP-1, and cellular-associated HIV-1-DNA and -RNA were quantified by flow cytometry, different immunoassays, and droplet digital PCR, respectively. The U de Mann-Whitney test evaluated differences between 3DR and 2DR. Immune recovery was evaluated using a general linear model for repeated measures adjusted for different co-variables. Results: Fifty participants per group were included. The median time on 3DR was 82 months for the 3DR group and 30 months for the 2DR group, after which it switched to 2DR for a median of 57 months. We did not find differences between both groups in any of the parameters analyzed. Specifically, some values in 3DR and 2DR were hs-CRP, 0.92 mg/L (0.45-2.23) vs. 1.23 (0.61-2.38); D-dimer, 190.0 µg/L (150.0-370.0) vs. 190.0 (150.0-397.5); IL-6, 2.8 pg/mL (1.3-5.3) vs. 3.2 (2.1-4.7); sCD14, 4.5 ng/mL (3.3-6.2) vs. 5.0 (3.6-6.1), respectively, all p ≥ 0.399. Conclusion: In the long term, switching to 2DR does not negatively affect immunologic parameters, inflammatory markers, or HIV-1 reservoir. Clinical trial registration: identifier NCT04076423.

The HIV-1 reservoir landscape in persistent elite controllers and transient elite controllers.

BACKGROUNDPersistent controllers (PCs) maintain antiretroviral-free HIV-1 control indefinitely over time, while transient controllers (TCs) eventually lose virological control. It is essential to characterize the quality of the HIV reservoir in terms of these phenotypes in order to identify the factors that lead to HIV progression and to open new avenues toward an HIV cure.METHODSThe characterization of HIV-1 reservoir from peripheral blood mononuclear cells was performed using next-generation sequencing techniques, such as full-length individual and matched integration site proviral sequencing (FLIP-Seq; MIP-Seq).RESULTSPCs and TCs, before losing virological control, presented significantly lower total, intact, and defective proviruses compared with those of participants on antiretroviral therapy (ART). No differences were found in total and defective proviruses between PCs and TCs. However, intact provirus levels were lower in PCs compared with TCs; indeed the intact/defective HIV-DNA ratio was significantly higher in TCs. Clonally expanded intact proviruses were found only in PCs and located in centromeric satellite DNA or zinc-finger genes, both associated with heterochromatin features. In contrast, sampled intact proviruses were located in permissive genic euchromatic positions in TCs.CONCLUSIONSThese results suggest the need for, and can give guidance to, the design of future research to identify a distinct proviral landscape that may be associated with the persistent control of HIV-1 without ART.FUNDINGInstituto de Salud Carlos III (FI17/00186, FI19/00083, MV20/00057, PI18/01532, PI19/01127 and PI22/01796), Gilead Fellowships (GLD22/00147). NIH grants AI155171, AI116228, AI078799, HL134539, DA047034, MH134823, amfAR ARCHE and the Bill and Melinda Gates Foundation.

Efficacy and safety of an early oral switch in low-risk Staphylococcus aureus bloodstream infection (SABATO): an international, open-label, parallel-group, randomised, controlled, non-inferiority trial.

BACKGROUND: Staphylococcus aureus bloodstream infection is treated with at least 14 days of intravenous antimicrobials. We assessed the efficacy and safety of an early switch to oral therapy in patients at low risk for complications related to S aureus bloodstream infection. METHODS: In this international, open-label, randomised, controlled, non-inferiority trial done in 31 tertiary care hospitals in Germany, France, the Netherlands, and Spain, adult patients with low-risk S aureus bloodstream infection were randomly assigned after 5-7 days of intravenous antimicrobial therapy to oral antimicrobial therapy or to continue intravenous standard therapy. Randomisation was done via a central web-based system, using permuted blocks of varying length, and stratified by study centre. The main exclusion criteria were signs and symptoms of complicated S aureus bloodstream infection, non-removable foreign devices, and severe comorbidity. The composite primary endpoint was the occurrence of any complication related to S aureus bloodstream infection (relapsing S aureus bloodstream infection, deep-seated infection, and mortality attributable to infection) within 90 days, assessed in the intention-to-treat population by clinical assessors who were masked to treatment assignment. Adverse events were assessed in all participants who received at least one dose of study medication (safety population). Due to slow recruitment, the scientific advisory committee decided on Jan 15, 2018, to stop the trial after 215 participants were randomly assigned (planned sample size was 430 participants) and to convert the planned interim analysis into the final analysis. The decision was taken without knowledge of outcome data, at a time when 126 participants were enrolled. The new sample size accommodated a non-inferiority margin of 10%; to claim non-inferiority, the upper bound of the 95% CI for the treatment difference (stratified by centre) had to be below 10 percentage points. The trial is closed to recruitment and is registered with ClinicalTrials.gov (NCT01792804), the German Clinical trials register (DRKS00004741), and EudraCT (2013-000577-77). FINDINGS: Of 5063 patients with S aureus bloodstream infection assessed for eligibility, 213 were randomly assigned to switch to oral therapy (n=108) or to continue intravenous therapy (n=105). Mean age was 63·5 (SD 17·2) years and 148 (69%) participants were male and 65 (31%) were female. In the oral switch group, 14 (13%) participants met the primary endpoint versus 13 (12%) in the intravenous group, with a treatment difference of 0·7 percentage points (95% CI -7·8 to 9·1; p=0·013). In the oral switch group, 36 (34%) of 107 participants in the safety population had at least one serious adverse event compared with 27 (26%) of 103 participants in the intravenous group (p=0·29). INTERPRETATION: Oral switch antimicrobial therapy was non-inferior to intravenous standard therapy in participants with low-risk S aureus bloodstream infection. However, it is necessary to carefully assess patients for signs and symptoms of complicated S aureus bloodstream infection at the time of presentation and thereafter before considering early oral switch therapy. FUNDING: Deutsche Forschungsgemeinschaft. TRANSLATIONS: For the German, Spanish, French and Dutch translations of the abstract see Supplementary Materials section.

Whole-genome characterisation of Escherichia coli isolates from patients with bacteraemia presenting with sepsis or septic shock in Spain: a multicentre cross-sectional study.

BACKGROUND: Escherichia coli is the most frequent cause of bloodstream infections (BSIs). About one-third of patients with BSIs due to E coli develop sepsis or shock. The objective of this study is to characterise the microbiological features of E coli blood isolates causing sepsis or septic shock to provide exploratory information for future diagnostic, preventive, or therapeutic interventions. METHODS: E coli blood isolates from a multicentre cross-sectional study of patients older than 14 years presenting with sepsis or septic shock (according to the Third International Consensus Definitions for Sepsis and Septic Shock criteria) from hospitals in Spain between Oct 4, 2016, and Oct 15, 2017, were studied by whole-genome sequencing. Phylogroups, sequence types (STs), serotype, FimH types, antimicrobial resistance (AMR) genes, pathogenicity islands, and virulence factors were identified. Susceptibility testing was performed by broth microdilution. The main outcome of this study was the characterisation of the E coli blood isolates in terms of population structure by phylogroups, groups (group 1: phylogroups B2, F, and G; group 2: A, B1, and C; group 3: D), and STs and distribution by geographical location and bloodstream infection source. Other outcomes were virulence score and prevalence of virulence-associated genes, pathogenicity islands, AMR, and AMR-associated genes. Frequencies were compared using χ² or Fisher's exact tests, and continuous variables using the Mann-Whitney test, with Bonferroni correction for multiple comparisons. FINDINGS: We analysed 224 isolates: 140 isolates (63%) were included in phylogenetic group 1, 52 (23%) in group 2, and 32 (14%) in group 3. 85 STs were identified, with four comprising 44% (n=98) of the isolates: ST131 (38 [17%]), ST73 (25 [11%]), ST69 (23 [10%]), and ST95 (12 [5%]). No significant differences in phylogroup or ST distribution were found according to geographical areas or source of bloodstream infection, except for ST95, which was more frequent in urinary tract infections than in other sources (11 [9%] of 116 vs 1 [1%] of 108, p=0·0045). Median virulence score was higher in group 1 (median 25·0 [IQR 20·5-29·0) than in group 2 (median 14·5 [9·0-20·0]; p<0·0001) and group 3 (median 21 [16·5-23·0]; p<0·0001); prevalence of several pathogenicity islands was higher in group 1. No significant differences were found between phylogenetic groups in proportions of resistance to antibiotics. ST73 had higher median virulence score (32 [IQR 29-35]) than the other predominant clones (median range 21-28). Some virulence genes and pathogenicity islands were significantly associated with each ST. ST131 isolates had higher prevalence of AMR and a higher proportion of AMR genes, notably blaCTX-M-15 and blaOXA-1. INTERPRETATION: In this exploratory study, the population structure of E coli causing sepsis or shock was similar to previous studies that included all bacteraemic isolates. Virulence genes, pathogenicity islands, and AMR genes were not randomly distributed among phylogroups or STs. These results provide a comprehensive characterisation of invasive E coli isolates causing severe response syndrome. Future studies are required to determine the contribution of these microbiological factors to severe clinical presentation and worse outcomes in patients with E coli bloodstream infection. FUNDING: Instituto de Salud Carlos III.

Association of microbiological factors with mortality in Escherichia coli bacteraemia presenting with sepsis/septic shock: a prospective cohort study.

OBJECTIVES: This study aimed to determine the association of Escherichia coli microbiological factors with 30-day mortality in patients with bloodstream infection (BSI) presenting with a dysregulated response to infection (i.e. sepsis or septic shock). METHODS: Whole-genome sequencing was performed on 224 E coli isolates of patients with sepsis/septic shock, from 22 Spanish hospitals. Phylogroup, sequence type, virulence, antibiotic resistance, and pathogenicity islands were assessed. A multivariable model for 30-day mortality including clinical and epidemiological variables was built, to which microbiological variables were hierarchically added. The predictive capacity of the models was estimated by the area under the receiver operating characteristic curve (AUROC) with 95% confidence intervals (CI). RESULTS: Mortality at day 30 was 31% (69 patients). The clinical model for mortality included (adjusted OR; 95% CI) age (1.04; 1.02-1.07), Charlson index ≥3 (1.78; 0.95-3.32), urinary BSI source (0.30; 0.16-0.57), and active empirical treatment (0.36; 0.11-1.14) with an AUROC of 0.73 (95% CI, 0.67-0.80). Addition of microbiological factors selected clone ST95 (3.64; 0.94-14.04), eilA gene (2.62; 1.14-6.02), and astA gene (2.39; 0.87-6.59) as associated with mortality, with an AUROC of 0.76 (0.69-0.82). DISCUSSION: Despite having a modest overall contribution, some microbiological factors were associated with increased odds of death and deserve to be studied as potential therapeutic or preventive targets.

Vedolizumab and ART in recent HIV-1 infection unveil the role of α4ß7 in reservoir size.

BACKGROUNDWe evaluated the safety and viral rebound, after analytical treatment interruption (ATI), of vedolizumab and ART in recent HIV-1 infection. We used this model to analyze the effect of α4ß7 on the HIV-1 reservoir size.METHODSParticipants started ART with monthly vedolizumab infusions, and ATI was performed at week 24. Biopsies were obtained from ileum and cecum at baseline and week 24. Vedolizumab levels, HIV-1 reservoir, flow cytometry, and cell-sorting and antibody competition experiments were assayed.RESULTSVedolizumab was safe and well tolerated. No participant achieved undetectable viremia off ART 24 weeks after ATI. Only a modest effect on the time to achieve more than 1,000 HIV-1 RNA copies/mL and the proportion of participants off ART was observed, being higher in the vedolizumab group compared with historical controls. Just before ATI, α4ß7 expression was associated with HIV-1 DNA and RNA in peripheral blood and with PD1 and TIGIT levels. Importantly, a complete blocking of α4ß7 was observed on peripheral CD4+ T cells but not in gut (ileum and cecum), where α4ß7 blockade and vedolizumab levels were inversely associated with HIV-1 DNA.CONCLUSIONOur findings support α4ß7 as an important determinant in HIV-1 reservoir size, suggesting the complete α4ß7 blockade in tissue as a promising tool for HIV-cure combination strategies.TRIAL REGISTRATIONClinicalTrials.gov NCT03577782.FUNDINGThis work was supported by the Instituto de Salud Carlos III (Fondo Europeo de Desarrollo Regional, "a way to make Europe," research contracts FI17/00186 and FI19/00083 and research projects PI18/01532, PI19/01127, PI22/01796), Conserjería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía (research projects P20/00906), the Red Temática de Investigación Cooperativa en SIDA (RD16/0025/0020), and the Spanish National Research Council.

Safety and effectiveness of isavuconazole in real-life non-neutropenic patients.

OBJECTIVES: Information is scarce on clinical experiences with non-neutropenic patients with invasive fungal infection (IFI) receiving isavuconazole. We aimed to report the safety and effectiveness of this drug as a first-line treatment or rescue in real life. METHODS: A retrospective, observational multicentric study of non-neutropenic patients who received isavuconazole as an IFI treatment at 12 different university hospitals (January 2018-2022). All patients met criteria for proven, probable or possible IFI according to EORTC-MSG. RESULTS: A total of 238 IFIs were treated with isavuconazole during the study period. Combination therapy was administered in 27.7% of cases. The primary IFI was aspergillosis (217, 91.2%). Other IFIs treated with isavuconazole were candidemia (n = 10), mucormycosis (n = 8), histoplasmosis (n = 2), cryptococcosis (n = 2), and others (n = 4). Median time of isavuconazole treatment was 29 days. Only 5.9% (n = 14) of cases developed toxicity, mainly hepatic-related (10 patients, 4.2%). Nine patients (3.8%) had treatment withdrawn. Successful clinical response at 12 weeks was documented in 50.5% of patients. CONCLUSION: Isavuconazole is an adequate treatment for non-neutropenic patients with IFIs. Toxicity rates were low and its effectiveness was comparable to other antifungal therapies previously reported.

Efficacy and safety of a structured de-escalation from antipseudomonal ß-lactams in bloodstream infections due to Enterobacterales (SIMPLIFY): an open-label, multicentre, randomised trial.

BACKGROUND: De-escalation from broad-spectrum to narrow-spectrum antibiotics is considered an important measure to reduce the selective pressure of antibiotics, but a scarcity of adequate evidence is a barrier to its implementation. We aimed to determine whether de-escalation from an antipseudomonal ß-lactam to a narrower-spectrum drug was non-inferior to continuing the antipseudomonal drug in patients with Enterobacterales bacteraemia. METHODS: An open-label, pragmatic, randomised trial was performed in 21 Spanish hospitals. Patients with bacteraemia caused by Enterobacterales susceptible to one of the de-escalation options and treated empirically with an antipseudomonal ß-lactam were eligible. Patients were randomly assigned (1:1; stratified by urinary source) to de-escalate to ampicillin, trimethoprim-sulfamethoxazole (urinary tract infections only), cefuroxime, cefotaxime or ceftriaxone, amoxicillin-clavulanic acid, ciprofloxacin, or ertapenem in that order according to susceptibility (de-escalation group), or to continue with the empiric antipseudomonal ß-lactam (control group). Oral switching was allowed in both groups. The primary outcome was clinical cure 3-5 days after end of treatment in the modified intention-to-treat (mITT) population, formed of patients who received at least one dose of study drug. Safety was assessed in all participants. Non-inferiority was declared when the lower bound of the 95% CI of the absolute difference in cure rate was above the -10% non-inferiority margin. This trial is registered with EudraCT (2015-004219-19) and ClinicalTrials.gov (NCT02795949) and is complete. FINDINGS: 2030 patients were screened between Oct 5, 2016, and Jan 23, 2020, of whom 171 were randomly assigned to the de-escalation group and 173 to the control group. 164 (50%) patients in the de-escalation group and 167 (50%) in the control group were included in the mITT population. 148 (90%) patients in the de-escalation group and 148 (89%) in the control group had clinical cure (risk difference 1·6 percentage points, 95% CI -5·0 to 8·2). The number of adverse events reported was 219 in the de-escalation group and 175 in the control group, of these, 53 (24%) in the de-escalation group and 56 (32%) in the control group were considered severe. Seven (5%) of 164 patients in the de-escalation group and nine (6%) of 167 patients in the control group died during the 60-day follow-up. There were no treatment-related deaths. INTERPRETATION: De-escalation from an antipseudomonal ß-lactam in Enterobacterales bacteraemia following a predefined rule was non-inferior to continuing the empiric antipseudomonal drug. These results support de-escalation in this setting. FUNDING: Plan Nacional de I+D+i 2013-2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades, Spanish Network for Research in Infectious Diseases; Spanish Clinical Research and Clinical Trials Platform, co-financed by the EU; European Development Regional Fund "A way to achieve Europe", Operative Program Intelligence Growth 2014-2020.

Stability Studies of Antipseudomonal Beta Lactam Agents for Outpatient Therapy.

Outpatient parenteral antimicrobial therapy (OPAT) is a useful treatment strategy against Pseudomonas aeruginosa and other multidrug-resistant bacteria. However, it is hindered by the lack of stability data for the administration of antibiotics under OPAT conditions. Our objective was to investigate the stability of nine antipseudomonal and broad-spectrum beta lactam antibiotics (aztreonam, cefepime, cefiderocol, ceftazidime, ceftazidime/avibactam, ceftolozane/tazobactam, meropenem, meropenem/vaborbactam, and piperacillin/tazobactam) to allow the spread of OPAT programs. All the antibiotics were diluted in 500 mL 0.9% sodium chloride and stored at 4, 25, 32, and 37 °C for 72 h in two different devices (infusion bags and elastomeric pumps). The solutions were considered stable if the color, clearness, and pH remained unchanged and if the percentage of intact drug was ≥90%. All the antimicrobials remained stable 72 h under refrigerated conditions and at least 30 h at 25 °C. At 32 °C, all the antibiotics except for meropenem and meropenem/vaborbactam remained stable for 24 h or more. At 37 °C, only aztreonam, piperacillin/tazobactam, cefepime, cefiderocol, and ceftolozane/tazobactam were stable for at least 24 h. The stability results were the same in the two devices tested. All the antibiotics studied are actual alternatives for the treatment of antipseudomonal or multidrug-resistant infections in OPAT programs, although the temperature of the devices is crucial to ensure antibiotic stability.