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.

Early Use of Sarilumab in Patients Hospitalized with COVID-19 Pneumonia and Features of Systemic Inflammation: the SARICOR Randomized Clinical Trial.

The objective of this study was to investigate the efficacy and safety of early treatment with sarilumab, added to standard of care (SOC), in hospitalized adults with COVID-19. Methods included phase II, open-label, randomized, controlled clinical trial of hospitalized patients with COVID-19 pneumonia and interleukin (IL)-6 levels ≥ 40 pg/mL and/or d-dimer > 1,500 ng/mL. Participants were randomized (1:1:1) to receive SOC (control group), SOC plus a single subcutaneous dose of sarilumab 200 mg (sarilumab-200 group), or SOC plus a single subcutaneous dose of sarilumab 400 mg (sarilumab-400 group). The primary outcome variable was the development of acute respiratory distress syndrome (ARDS) requiring high-flow nasal oxygenation (HFNO), non-invasive mechanical ventilation (NIMV) or invasive mechanical ventilation (IMV) at day 28. One-hundred and 15 participants (control group, n = 39; sarilumab-200, n = 37; sarilumab-400, n = 39) were included. At randomization, 104 (90%) patients had supplemental oxygen and 103 (90%) received corticosteroids. Eleven (28%) patients in the control group, 10 (27%) in sarilumab-200, and five (13%) in sarilumab-400 developed the primary outcome (hazard ratio [95% CI] of sarilumab-400 vs control group: 0.41 [0.14, 1.18]; P = 0.09). Seven (6%) patients died: three in the control group and four in sarilumab-200. There were no deaths in sarilumab-400 (P = 0.079, log-rank test for comparisons with the control group). In patients recently hospitalized with COVID-19 pneumonia and features of systemic inflammation, early IL-6 blockade with a single dose of sarilumab 400 mg was safe and associated with a trend for better outcomes. (This study has been registered at ClinicalTrials.gov under identifier NCT04357860.).

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.

Conventional Hospitalization versus Sequential Outpatient Parenteral Antibiotic Therapy for Staphylococcus aureus Bacteremia: Post-Hoc Analysis of a Multicenter Observational Cohort.

It is not known whether sequential outpatient parenteral antimicrobial (OPAT) is as safe and effective as conventional hospitalization in patients with S. aureus bacteremia (SAB). A post-hoc analysis of the comparative effectiveness of conventional hospitalization versus sequential OPAT was performed in two prospective Spanish cohorts of patients with S. aureus bacteremia. The PROBAC cohort is a national, multicenter, prospective observational cohort of patients diagnosed in 22 Spanish hospitals between October 2016 and March 2017. The DOMUS OPAT cohort is a prospective observational cohort including patients from two university hospitals in Seville, Spain from 2012 to 2021. Multivariate regression was performed, including a propensity score (PS) for receiving OPAT, stratified analysis according to PS quartiles, and matched pair analyses based on PS. Four hundred and thirteen patients were included in the analysis: 150 in sequential OPAT and 263 in the full hospitalization therapy group. In multivariate analysis, including PS and center effect as covariates, 60-day treatment failure was lower in the OPAT group than in the full hospitalization group (p < 0.001; OR 0.275, 95%CI 0.129−0.584). In the PS-based matched analyses, sequential treatment under OPAT was not associated with higher 60-day treatment failure (p = 0.253; adjusted OR 0.660; % CI 0.324−1.345). OPAT is a safe and effective alternative to conventional in-patient therapy for completion of treatment in well-selected patients with SAB, mainly those associated with a low-risk source and without end-stage kidney disease.

Role of IP-10 to Predict Clinical Progression and Response to IL-6 Blockade With Sarilumab in Early COVID-19 Pneumonia. A Subanalysis of the SARICOR Clinical Trial.

Background: The Clinical Trial of Sarilumab in Adults With COVID-19 (SARICOR) showed that patients with coronavirus disease 2019 (COVID-19) pneumonia and increased levels of interleukin (IL)-6 might benefit from blockade of the IL-6 pathway. However, the benefit from this intervention might not be uniform. In this subanalysis, we sought to determine if other immunoactivation markers, besides IL-6, could identify which subgroup of patients benefit most from this intervention. Methods: The SARICOR trial was a phase II, open-label, multicenter, controlled trial (July 2020-March 2021) in which patients were randomized to receive usual care (UC; control group), UC plus a single dose of sarilumab 200 mg (sarilumab-200 group), or UC plus a single dose of sarilumab 400 mg (sarilumab-400 group). Patients who had baseline serum samples for cytokine determination (IL-8, IL-10, monocyte chemoattractant protein-1, interferon-inducible protein [IP]-10) were included in this secondary analysis. Progression to acute respiratory distress syndrome (ARDS) according to cytokine levels and treatment received was evaluated. Results: One hundred one (88%) of 115 patients enrolled in the SARICOR trial had serum samples (control group: n = 33; sarilumab-200: n = 33; sarilumab-400: n = 35). Among all evaluated biomarkers, IP-10 showed the strongest association with treatment outcome. Patients with IP-10 ≥2500 pg/mL treated with sarilumab-400 had a lower probability of progression (13%) compared with the control group (58%; hazard ratio, 0.19; 95% CI, 0.04-0.90; P = .04). Conversely, patients with IP-10 <2500 pg/mL did not show these differences. Conclusions: IP-10 may predict progression to ARDS in patients with COVID-19 pneumonia and IL-6 levels >40 pg/mL. Importantly, IP-10 value <2500 pg/mL might discriminate those individuals who might not benefit from sarilumab therapy among those with high IL-6 levels.

Risk of cardiac device-related infection in patients with late-onset bloodstream infection. Analysis on a National Cohort.

OBJECTIVES: To determine the incidence of cardiac device-related infection (CDRI) among patients with cardiac device (CD) during late-onset bloodstream infection (BSI) and to identify the risk factors associated with CDRI. METHODS: Patients with a CD (cardiac implantable electronic devices -CIED- and/or prosthetic heart valve -PHV-) and late-onset-BSI (>1 year after the CD implantation/last manipulation) were selected from the PROBAC project, a prospective, observational cohort study including adult patients with bacteraemia consecutively admitted to 26 Spanish hospitals from October 2016 to March 2017. Multivariate analyses using logistic regression were performed to identify the risk factors associated with CDRI. RESULTS: 317 BSI from patients carrying a CD were registered, 187 (56.2%) were late-onset-BSI. A total of 40 (21.4%) CDRI were identified during late-onset-BSI. The CDRI cumulative incidence in Gram-positive-BSI was 41.8% (38/91), with S. aureus, Enterococcus spp. and viridans streptococci showing the greatest percentages: 40% (12/30), 42% (11/26) and 75% (6/8), respectively. Independent predictors of CDRI were an unknown source of infection (OR: 2.88 [CI 95%:1.18-7.06], p = 0.02), Gram-positive-aetiology (23.1 [5.23-102.1], p < 0.001) and persistent bacteraemia (4.81 [1.21-19], p = 0.03). In an exploratory analysis, S. aureus (3.99 [1.37-11.65], p = 0.011), Enterococcus spp. (5.21 [1.76-15.4], p = 0.003) and viridans streptococci (28.7 [4.71-173.5], p < 0.001) aetiology were also found to be risk factors for CDRI. CONCLUSIONS: CDRI during late-onset-BSI is a frequent phenomenon. Risk of CDRI differs among species, happening in almost half of the Gram-positive-BSI. An unknown source of the primary infection, Gram-positive-aetiology -especially S. aureus, Enterococcus spp. and viridans streptococci-, and persistent bacteraemia were identified as risk factors for CDRI.

Revisiting the epidemiology of bloodstream infections and healthcare-associated episodes: results from a multicentre prospective cohort in Spain (PRO-BAC Study).

The epidemiology of bloodstream infections (BSIs) is dynamic as it depends on microbiological, host and healthcare system factors. The aim of this study was to update the information regarding the epidemiology of BSIs in Spain considering the type of acquisition. An observational, prospective cohort study in 26 Spanish hospitals from October 2016 through March 2017 including all episodes of BSI in adults was performed. Bivariate analyses stratified by type of acquisition were performed. Multivariate analyses were performed by logistic regression. Overall, 6345 BSI episodes were included; 2510 (39.8%) were community-acquired (CA), 1661 (26.3%) were healthcare-associated (HCA) and 2056 (32.6%) hospital-acquired (HA). The 30-day mortality rates were 11.6%, 19.5% and 22.0%, respectively. The median age of patients was 71 years (interquartile range 60-81 years) and 3656 (58.3%; 95% confidence interval 57.1-59.6%) occurred in males. The proportions according to patient sex varied according to age strata. Escherichia coli (43.8%), Klebsiella spp. (8.9%), Staphylococcus aureus (8.9%) and coagulase-negative staphylococci (7.4%) were the most frequent pathogens. Multivariate analyses confirmed important differences between CA and HCA episodes, but also between HCA and HA episodes, in demographics, underlying conditions and aetiology. In conclusion, we have updated the epidemiological information regarding patients' profiles, underlying conditions, frequency of acquisition types and aetiological agents of BSI in Spain. HCA is confirmed as a distinct type of acquisition.