Proteus species bloodstream infections: Comparative epidemiology of three species.

BACKGROUND: Although Proteus species are occasional causes of serious infections, their epidemiology has not been well defined. The objective was to describe the overall and species-specific occurrence and determinants of Proteus species bloodstream infection (BSI) in a large Australian population. METHODS: All Queensland residents with Proteus species BSI identified within the publicly funded healthcare system between 2000 and 2019 were included. RESULTS: A total of 2,143 incident episodes of Proteus species BSI were identified among 2,079 Queensland residents. The prevalence of comorbid illness differed with higher Charlson comorbidity scores observed with P. penneri and P. vulgaris, and higher prevalence of liver disease with P. penneri, higher comorbid cancer with P. vulgaris, and lower diabetes and renal disease prevalence with P. mirabilis BSIs. CONCLUSION: This study provides novel information on the epidemiology of Proteus species BSI.

Intersectoral Partnerships Between Local Governments and Health Organisations in High-Income Contexts: A Scoping Review.

BACKGROUND: Local governments are the closest level of government to the communities they serve. Traditionally providing roads, rates and garbage services, they are also responsible for policy and regulation, particularly land use planning and community facilities and services that have direct and indirect impacts on (equitable) health and well-being. Partnerships between health agencies and local government are therefore an attractive proposition to progress actions that positively impact community health and well-being. Yet, the factors underpinning these partnerships across different contexts are underdeveloped, as mechanisms to improve population health and well-being. METHODS: A scoping review was conducted to gain insight into the concepts, theories, sources, and knowledge gaps that shape partnerships between health and local governments. The search strategy followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines and was informed by a critical realist approach that identifies necessary, contingent and contextual factors in the literature. MEDLINE, Scopus, Web of Science, and ProQuest Central databases were searched for studies published between January 2005 and July 2021. RESULTS: The search yielded 3472 studies, after deleting duplicates and initial title and abstract screening, 188 papers underwent full text review. Twenty-nine papers were included in the review. Key themes shaping partnerships included funding and resources; partnership qualities; governance and policy; and evaluation and measures of success. The functional, organisational and individual aspects of these themes are explored and presented in a framework. CONCLUSION: Given that local government are the closest level of government to community, this paper provides a sophisticated roadmap that can underpin partnerships between local government and health agencies aiming to influence population health outcomes. By identifying key themes across contexts, we provide a framework that may assist in designing and evaluating evidence-informed health and local government partnerships.

High-risk Escherichia coli clones that cause neonatal meningitis and association with recrudescent infection.

Neonatal meningitis is a devastating disease associated with high mortality and neurological sequelae. Escherichia coli is the second most common cause of neonatal meningitis in full-term infants (herein NMEC) and the most common cause of meningitis in preterm neonates. Here, we investigated the genomic relatedness of a collection of 58 NMEC isolates spanning 1974-2020 and isolated from seven different geographic regions. We show NMEC are comprised of diverse sequence types (STs), with ST95 (34.5%) and ST1193 (15.5%) the most common. No single virulence gene profile was conserved in all isolates; however, genes encoding fimbrial adhesins, iron acquisition systems, the K1 capsule, and O antigen types O18, O75, and O2 were most prevalent. Antibiotic resistance genes occurred infrequently in our collection. We also monitored the infection dynamics in three patients that suffered recrudescent invasive infection caused by the original infecting isolate despite appropriate antibiotic treatment based on antibiogram profile and resistance genotype. These patients exhibited severe gut dysbiosis. In one patient, the causative NMEC isolate was also detected in the fecal flora at the time of the second infection episode and after treatment. Thus, although antibiotics are the standard of care for NMEC treatment, our data suggest that failure to eliminate the causative NMEC that resides intestinally can lead to the existence of a refractory reservoir that may seed recrudescent infection.

Building CapaCITY/É for sustainable transportation: protocol for an implementation science research program in healthy cities.

INTRODUCTION: Improving sustainable transportation options will help cities tackle growing challenges related to population health, congestion, climate change and inequity. Interventions supporting active transportation face many practical and political hurdles. Implementation science aims to understand how interventions or policies arise, how they can be translated to new contexts or scales and who benefits. Sustainable transportation interventions are complex, and existing implementation science frameworks may not be suitable. To apply and adapt implementation science for healthy cities, we have launched our mixed-methods research programme, CapaCITY/É. We aim to understand how, why and for whom sustainable transportation interventions are successful and when they are not. METHODS AND ANALYSIS: Across nine Canadian municipalities and the State of Victoria (Australia), our research will focus on two types of sustainable transportation interventions: all ages and abilities bicycle networks and motor vehicle speed management interventions. We will (1) document the implementation process and outcomes of both types of sustainable transportation interventions; (2) examine equity, health and mobility impacts of these interventions; (3) advance implementation science by developing a novel sustainable transportation implementation science framework and (4) develop tools for scaling up and scaling out sustainable transportation interventions. Training activities will develop interdisciplinary scholars and practitioners able to work at the nexus of academia and sustainable cities. ETHICS AND DISSEMINATION: This study received approval from the Simon Fraser University Office of Ethics Research (H22-03469). A Knowledge Mobilization Hub will coordinate dissemination of findings via a website; presentations to academic, community organisations and practitioner audiences; and through peer-reviewed articles.

Pseudomonas stutzeri bloodstream infection is a prevailing community-onset disease with important mortality rates: results from a retrospective observational study in Australia.

BACKGROUND: The recognition of Pseudomonas stutzeri as a cause of infections in humans has been increasing. However, only case reports and small series of P. stutzeri bloodstream infections have been published. Epidemiological data on these infections are extremely scarce. Our objective was to describe the incidence, epidemiology, antimicrobial resistance rates, and outcomes of P. stutzeri bloodstream infections in a large population-based cohort in Australia. METHODS: Retrospective, laboratory-based surveillance study conducted in Queensland, Australia (population ≈ 5 million) during 2000-2019. Clinical information was obtained from public hospital admissions and vital statistics databases. RESULTS: In total, 228 episodes of P. stutzeri bloodstream infections were identified. Increased incidence was observed in the later years, especially in older men, and was higher during the rainy months of the year and in the warmest and more humid regions of the state. The majority of bloodstream infections were community-onset with 120 (52.6%) community-associated and 59 (25.9%) ambulatory healthcare-associated episodes. Only 49 cases (21.5%) were nosocomial. The most common foci of infection were skin and soft tissue, lower respiratory tract, and intra-abdominal. No isolate showed antimicrobial resistance. Thirty-one patients (13.6%) died. The mortality rate in patients with a respiratory infectious source was higher (21%). CONCLUSIONS: P. stutzeri bloodstream infection was predominantly a community-onset condition including ambulatory healthcare related cases, with increasing incidence, especially in older males. No antimicrobial resistance was observed. Mortality was high in patients with respiratory infectious source. This new observational data have implications when considering the epidemiology of these infections and for patient management.

Emergence and clonal expansion of a qacA-harbouring sequence type 45 lineage of methicillin-resistant Staphylococcus aureus.

The past decade has seen an increase in the prevalence of sequence type (ST) 45 methicillin-resistant Staphylococcus aureus (MRSA), yet the underlying drivers for its emergence and spread remain unclear. To better understand the worldwide dissemination of ST45 S. aureus, we performed phylogenetic analyses of Australian isolates, supplemented with a global population of ST45 S. aureus genomes. Our analyses revealed a distinct lineage of multidrug-resistant ST45 MRSA harbouring qacA, predominantly found in Australia and Singapore. Bayesian inference predicted that the acquisition of qacA occurred in the late 1990s. qacA was integrated into a structurally variable region of the chromosome containing Tn552 (carrying blaZ) and Tn4001 (carrying aac(6')-aph(2")) transposable elements. Using mutagenesis and in vitro assays, we provide phenotypic evidence that qacA confers tolerance to chlorhexidine. These findings collectively suggest both antimicrobial resistance and the carriage of qacA may play a role in the successful establishment of ST45 MRSA.

Achievement of therapeutic antibiotic exposures using Bayesian dosing software in critically unwell children and adults with sepsis.

PURPOSE: Early recognition and effective treatment of sepsis improves outcomes in critically ill patients. However, antibiotic exposures are frequently suboptimal in the intensive care unit (ICU) setting. We describe the feasibility of the Bayesian dosing software Individually Designed Optimum Dosing Strategies (ID-ODS™), to reduce time to effective antibiotic exposure in children and adults with sepsis in ICU. METHODS: A multi-centre prospective, non-randomised interventional trial in three adult ICUs and one paediatric ICU. In a pre-intervention Phase 1, we measured the time to target antibiotic exposure in participants. In Phase 2, antibiotic dosing recommendations were made using ID-ODS™, and time to target antibiotic concentrations were compared to patients in Phase 1 (a pre-post-design). RESULTS: 175 antibiotic courses (Phase 1 = 123, Phase 2 = 52) were analysed from 156 participants. Across all patients, there was no difference in the time to achieve target exposures (8.7 h vs 14.3 h in Phase 1 and Phase 2, respectively, p = 0.45). Sixty-one courses in 54 participants failed to achieve target exposures within 24 h of antibiotic commencement (n = 36 in Phase 1, n = 18 in Phase 2). In these participants, ID-ODS™ was associated with a reduction in time to target antibiotic exposure (96 vs 36.4 h in Phase 1 and Phase 2, respectively, p < 0.01). These patients were less likely to exhibit subtherapeutic antibiotic exposures at 96 h (hazard ratio (HR) 0.02, 95% confidence interval (CI) 0.01-0.05, p < 0.01). There was no difference observed in in-hospital mortality. CONCLUSIONS: Dosing software may reduce the time to achieve target antibiotic exposures. It should be evaluated further in trials to establish its impact on clinical outcomes.

Time to positivity is a risk factor for death among patients with bloodstream infections: a population-based cohort.

OBJECTIVES: Studies examining time to positivity (TTP) of blood cultures as a risk factor for death have shown conflicting results. The study objective was to examine the effect of TTP on all-cause-30-day case-fatality among a population-based cohort of patients with bloodstream infections (BSI). METHODS: A retrospective cohort study including all residents of Queensland, Australia with incident monomicrobial BSI managed in the publicly funded healthcare system from 2000 to 2019 was performed. Clinical, TTP and all-cause 30-day case-fatality information was obtained from state-wide sources. RESULTS: A cohort of 88 314 patients was assembled. The median TTP was 14 hours, with 5th, 25th, 75th, and 95th percentiles of 4, 10, 20, and 53 hours, respectively. The TTP varied significantly by BSI aetiology. The 30-day all-cause case-fatality rate was 2606/17 879 (14.6%), 2834/24 272 (11.7%), 2378/20 359 (11.7%), and 2752/22 431 (12.3%) within the first, second, third, and fourth TTP quartiles, respectively (p < 0.0001). After adjustment for age, sex, onset, comorbidity, and focus of infection, TTP within 10 hours (first quartile) was associated with a significantly increased risk for death (odds ratio 1.43; 95% CI, 1.35-1.50; p < 0.001). After adjustment for confounding variables (odds ratio; 95% CI), TTP within the first quartile for Staphylococcus aureus (1.56; 1.41-1.73), Streptococcus pneumoniae (1.91; 1.49-2.46), ß-hemolytic streptococci (1.23; 1.00-1.50), Pseudomonas species (2.23; 1.85-2.69), Escherichia coli (1.37; 1.23-1.53), Enterobacterales (1.38; 1.16-1.63), other Gram-negatives (1.68; 1.36-2.06), and anaerobes (1.58; 1.28-1.94) increased the risk for case-fatality. DISCUSSION: This population-based analysis provides evidence that TTP is an important determinant of mortality among patients with BSI.

Scoping review of risk-scoring tools for early prediction of bloodstream infections caused by carbapenem-resistant Enterobacterales: do we really have a reliable risk-scoring tool?

Background: Bloodstream infections (BSIs) caused by carbapenem-resistant Enterobacterales (CRE) are a global health concern. Rapid identification of CRE may improve patient outcomes and reduce inappropriate antibiotic prescription. The use of risk-scoring tools (RSTs) can be valuable for optimizing the decision-making process for empirical antibiotic therapy of suspected CRE bacteraemia. These tools can also be used to triage use of expensive rapid diagnostic methods. Methods: We systematically reviewed the relevant literature in PubMed/MEDLINE, CINAHL, Cochrane, Web of Science, Embase and Scopus up to 1 November 2022 to identify RSTs that predict CRE BSIs. The literature review and analysis of the articles were performed by two researchers; any inconsistencies were resolved through discussion. Results: We identified 9 RSTs developed for early prediction of CRE BSIs and only logistic regression was used for most studies. These RSTs were quite different from each other in terms of their performance and the variables they included. They also had notable limitations and very few of them were externally validated. Conclusions: RSTs for early prediction of CRE BSIs have limitations and lack of external validity outside the local setting in which they were developed. Future studies to identify optimal RSTs in high and low CRE-endemic settings are warranted. Approaches based on rapid diagnostics and RSTs should be compared with a treatment approach using both methods in a randomized controlled trial.

HAIviz: an interactive dashboard for visualising and integrating healthcare-associated genomic epidemiological data.

Existing tools for phylogeographic and epidemiological visualisation primarily provide a macro-geographic view of epidemic and pandemic transmission events but offer little support for detailed investigation of outbreaks in healthcare settings. Here, we present HAIviz, an interactive web-based application designed for integrating and visualising genomic epidemiological information to improve the tracking of healthcare-associated infections (HAIs). HAIviz displays and links the outbreak timeline, building map, phylogenetic tree, patient bed movements, and transmission network on a single interactive dashboard. HAIviz has been developed for bacterial outbreak investigations but can be utilised for general epidemiological investigations focused on built environments for which visualisation to customised maps is required. This paper describes and demonstrates the application of HAIviz for HAI outbreak investigations.

Win ratio analyses of piperacillin-tazobactam versus meropenem for ceftriaxone non-susceptible Escherichia coli or Klebsiella pneumoniae bloodstream infections: Post-hoc insights from the MERINO trial.

BACKGROUND: Clinical trials of treatments for serious infections commonly use the primary endpoint of all-cause mortality. However, many trial participants survive their infection and this endpoint may not truly reflect important benefits and risks of therapy. The win ratio uses a hierarchical composite endpoint that can incorporate and prioritise outcome measures by relative clinical importance. METHODS: The win ratio methodology was applied post-hoc to outcomes observed in the MERINO trial, which compared piperacillin-tazobactam with meropenem. We quantified the win ratio with a primary hierarchical composite endpoint, including all-cause mortality, microbiological relapse and secondary infection. A win ratio of one would correspond to no difference between the two antibiotics, while a ratio less than one favors meropenem. Further analyses were performed to calculate the win odds and to introduce a continuous outcome variable in order to reduce ties. RESULTS: With the hierarchy of all-cause mortality, microbiological relapse and secondary infection, the win ratio estimate was 0.40 (95% CI: 0.22, 0.71; p=0.002), favoring meropenem over piperacillin-tazobactam. However, 73.4% of the pairs were tied due to the small proportion of events. The win odds, a modification of the win ratio accounting for ties, was 0.79 (95% CI: 0.68, 0.92). The addition of length of stay to the primary composite, greatly minimised the number of ties (4.6%) with a win ratio estimate of 0.77 (95% CI: 0.60-0.99; p=0.04). CONCLUSIONS: The application of the win ratio methodology to the MERINO trial data illustrates its utility and feasibility for use in antimicrobial trials.

Australian and Canadian financial wellbeing policy landscape during COVID-19: An equity-informed policy scan.

Background: This targeted and comprehensive policy scan examined how different levels of governments in Australia and Canada responded to the financial crisis brought on by the COVID-19 pandemic. We mapped the types of early policy responses addressing financial strain and promoting financial wellbeing. We also examined their equity considerations. Methods: Through a systematic search, snowballing, and manual search, we identified Canadian and Australian policies at all government levels related to financial strain or financial wellbeing enacted or amended in 2019-2020. Using a deductive-inductive approach, policies were categorized by jurisdiction level, focal areas, and target population groups. Results: In total, 213 and 97 policies in Canada and Australia, respectively, were included. Comparisons between Canadian and Australian policies indicated a more diversified and equity-targeted policy landscape in Canada. In both countries, most policies focused on individual and family finances, followed by housing and employment areas. Conclusions: The policy scan identified gaps and missed opportunities in the early policies related to financial strain and financial wellbeing. While fast, temporary actions addressed individuals' immediate needs, we recommend governments develop a longer-term action plan to tackle the root causes of financial strain and poor financial wellbeing for better health and non-health crisis preparedness. Statement on Ethics and Informed Consent: This research reported in this paper did not require ethical clearance or patient informed consent as the data sources were published policy documents. This study did not involve data collection with humans (or animals), nor any secondary datasets involving data provided by humans (or from animal studies).

Rapid nanopore sequencing and predictive susceptibility testing of positive blood cultures from intensive care patients with sepsis.

We aimed to evaluate the performance of Oxford Nanopore Technologies (ONT) sequencing from positive blood culture (BC) broths for bacterial identification and antimicrobial susceptibility prediction. Patients with suspected sepsis in four intensive care units were prospectively enrolled. Human-depleted DNA was extracted from positive BC broths and sequenced using ONT (MinION). Species abundance was estimated using Kraken2, and a cloud-based system (AREScloud) provided in silico predictive antimicrobial susceptibility testing (AST) from assembled contigs. Results were compared to conventional identification and phenotypic AST. Species-level agreement between conventional methods and AST predicted from sequencing was 94.2% (49/52), increasing to 100% in monomicrobial infections. In 262 high-quality AREScloud AST predictions across 24 samples, categorical agreement (CA) was 89.3%, with major error (ME) and very major error (VME) rates of 10.5% and 12.1%, respectively. Over 90% CA was achieved for some taxa (e.g., Staphylococcus aureus) but was suboptimal for Pseudomonas aeruginosa. In 470 AST predictions across 42 samples, with both high quality and exploratory-only predictions, overall CA, ME, and VME rates were 87.7%, 8.3%, and 28.4%. VME rates were inflated by false susceptibility calls in a small number of species/antibiotic combinations with few representative resistant isolates. Time to reporting from sequencing could be achieved within 8-16 h from BC positivity. Direct sequencing from positive BC broths is feasible and can provide accurate predictive AST for some species. ONT-based approaches may be faster but significant improvements in accuracy are required before it can be considered for clinical use.IMPORTANCESepsis and bloodstream infections carry a high risk of morbidity and mortality. Rapid identification and susceptibility prediction of causative pathogens, using Nanopore sequencing direct from blood cultures, may offer clinical benefit. We assessed this approach in comparison to conventional phenotypic methods and determined the accuracy of species identification and susceptibility prediction from genomic data. While this workflow holds promise, and performed well for some common bacterial species, improvements in sequencing accuracy and more robust predictive algorithms across a diverse range of organisms are required before this can be considered for clinical use. However, results could be achieved in timeframes that are faster than conventional phenotypic methods.

Persistence of Detectable Pathogens by Culture-Independent Systems (T2 Magnetic Resonance) in Patients With Bloodstream Infection: Prognostic Role and Possible Clinical Implications.

BACKGROUND: Persistent Staphylococcus aureus bacteremia is associated with metastatic infection and adverse outcomes, whereas gram-negative bacteremia is normally transient and shorter course therapy is increasingly advocated for affected patients. Whether the prolonged detection of pathogen DNA in blood by culture-independent systems could have prognostic value and guide management decisions is unknown. METHODS: We performed a multicenter, prospective, observational study on 102 patients with bloodstream infection (BSI) to compare time to bloodstream clearance according to T2 magnetic resonance and blood cultures over a 4-day follow-up. We also explored the association between duration of detectable pathogens according to T2 magnetic resonance (magnetic resonance-DNAemia [MR-DNAemia]) and clinical outcomes. RESULTS: Time to bloodstream clearance according to T2 magnetic resonance was significantly longer than blood culture clearance (HR, .54; 95% CI, .39-.75) and did not differ according to the causative pathogen (P = .5). Each additional day of MR-DNAemia increased the odds of persistent infection (defined as metastatic infection or delayed source control) both in the overall population (OR, 1.98; 95% CI, 1.45-2.70) and in S. aureus (OR, 1.92; 95% CI, 1.12-3.29) and gram-negative bacteremia (OR, 2.21; 95% CI, 1.35-3.60). MR-DNAemia duration was also associated with no improvement in Sequential Organ Failure Assessment score at day 7 from infection onset (OR, 1.76; 95% CI, 1.21-2.56). CONCLUSIONS: T2 magnetic resonance may help diagnose BSI in patients on antimicrobials with negative blood cultures as well as to identify patients with metastatic infection, source control failure, or adverse short-term outcome. Future studies may inform its usefulness within the setting of antimicrobial stewardship programs.

The global epidemiology of ventilator-associated pneumonia caused by multi-drug resistant Pseudomonas aeruginosa: A systematic review and meta-analysis.

OBJECTIVES: The objective of this systematic review and meta-analysis was to estimate the global prevalence of multi-drug resistant (MDR) Pseudomonas aeruginosa causing ventilator-associated pneumonia (VAP). METHODS: The systematic search was conducted in four databases. Original studies describing MDR P. aeruginosa VAP prevalence in adults from 2012- 2022 were included. A meta-analysis, using the random effects model, was conducted for overall, subgroups (country, published year, study duration, and study design), and European data, respectively. Univariate meta-regression based on pooled estimates was also conducted. Systematic review registered in International Prospective Register of Systematic Review (CRD42022384035). RESULTS: In total of 31 studies, containing a total of 7951 cases from 16 countries, were included. The overall pooled prevalence of MDR among P. aeruginosa causing VAP was 33% (95% confidence interval [CI] 27.7-38.3%). The highest prevalence was for Iran at 87.5% (95% CI 69-95.7%), and the lowest was for the USA at 19.7% (95% CI 18.6-20.7%). The European prevalence was 29.9% (95% CI 23.2-36.7%). CONCLUSIONS: This review indicates that the prevalence of MDR P. aeruginosa in patients with VAP is generally high and varies significantly between countries; however, data are insufficient for many countries. The data in this study can provide a reference for VAP management and drug customisation strategies.

Mortality, hospital length of stay, and recurrent bloodstream infections associated with extended-spectrum beta-lactamase-producing Escherichia coli in a low prevalence region: A 20-year population-based large cohort study.

OBJECTIVES: This population-based study aimed to investigate the risk factors and effect of extended-spectrum beta-lactamase (ESBL) production on clinical outcomes in Escherichia coli bloodstream infection (BSI) patients. METHODS: The study population was defined as patients aged ≥15 years with E. coli BSI in Queensland, Australia, from 2000 to 2019. Outcomes were defined as 30-day case fatality, hospital length of stay (LOS), and recurrent E. coli BSI. RESULTS: A total of 27,796 E. coli BSIs were identified, of which 1112 (4.0%) were ESBL-producers. Patients with ESBL-Ec BSI were more frequently older, male, with comorbidity, recurrent E. coli BSI, and less likely with community-associated community-onset infections as compared to non-ESBL-Ec BSI patients. The standardized mortality rate of ESBL-Ec BSI increased 8-fold from 2000 to 2019 (1 to 8 per million residents) and case fatality was 12.8% (n = 142) at 30 days from positive blood culture. Patients with ESBL-Ec BSI were not at higher risk of 30-day case fatality (adjusted hazard ratio [HR] = 0.98, 95% CI: 0.83-1.17), but had higher risk of recurring episodes (adjusted subdistribution HR = 1.58, 95% CI: 1.29-1.92) and observed 14% longer LOS (adjusted incidence rate ratio = 1.14, 95% CI: 1.10-1.18) than non-ESBL-Ec BSI patients. CONCLUSION: In this large patient cohort, ESBL-Ec BSI did not increase case fatality risk but observed higher hospital LOS and recurrent E. coli BSI than non-ESBL-Ec BSI. Clinical resources are warranted to account for the higher morbidity risk associated with ESBL production and incidence.

Vibrio species bloodstream infections in Queensland, Australia.

BACKGROUND: Vibrio species bloodstream infections have been associated with significant mortality and morbidity. Limited information is available regarding the epidemiology of bloodstream infections because of Vibrio species in the Australian context. AIMS: The objective of this study was to define the incidence and risk factors for developing Vibrio species bloodstream infections and compare differences between different species. METHODS: All patients with Vibrio spp. isolated from positive blood cultures between 1 January 2000 and 31 December 2019 were identified by the state-wide Pathology Queensland laboratory. Demographics, clinical foci of infections and comorbid conditions were collected in addition to antimicrobial susceptibility results. RESULTS: About 100 cases were identified between 2000 and 2019 with an incidence of 1.2 cases/1 million person-years. Seasonal and geographical variation occurred with the highest incidence in the summer months and in the tropical north. Increasing age, male sex and multiple comorbidities were identified as risk factors. Vibrio vulnificus was isolated most frequently and associated with the most severe disease. Overall case fatality was 19%. CONCLUSIONS: There is potential for increasing cases of Vibrio species infections globally with ageing populations and climate change. Ongoing clinical awareness is required to ensure optimal patient outcomes.

Host response signature trends in persistent bacteraemia and metastatic infection due to Staphylococcus aureus and Gram-negative bacilli: a prospective multicentre observational study.

BACKGROUND: A prompt diagnosis of bacteraemia and sepsis is essential. Markers to predict the risk of persistent bacteraemia and metastatic infection are lacking. SeptiCyte RAPID is a host response assay stratifying patients according to the risk of infectious vs sterile inflammation through a scoring system (SeptiScore). In this study we explore the association between SeptiScore and persistent bacteraemia as well as metastatic and persistent infection in the context of a proven bacteraemia episode. METHODS: This is a prospective multicentre observational 14-month study on patients with proven bacteraemia caused by Staphylococcus aureus or Gram-negative bacilli. Samples for assessment by SeptiCyte were collected with paired blood cultures for 4 consecutive days after the index blood culture. RESULTS: We included 86 patients in the study, 40 with S. aureus and 46 with Gram-negative bacilli bacteraemia. SeptiScores over the follow-up were higher in patients with Gram-negative compared to S. aureus bacteraemia (median 6.4, IQR 5.5-7.4 vs 5.6 IQR 5.1-6.2, p = 0.002). Higher SeptiScores were found to be associated with positive blood cultures at follow-up (AUC = 0.86, 95%CI 0.68-1.00) and with a diagnosis of metastatic infection at day 1 and 2 of follow-up (AUC = 0.79, 95%CI 0.57-1.00 and AUC = 0.82, 95%CI 0.63-1.00 respectively) in the context of Gram-negative bacteraemia while no association between SeptiScore and the outcomes of interest was observed in S. aureus bacteraemia. Mixed models confirmed the association of SeptiScore with positive blood cultures at follow-up (p = 0.04) and metastatic infection (p = 0.03) in the context of Gram-negative bacteraemia but not S. aureus bacteraemia after adjusting for confounders. CONCLUSIONS: SeptiScores differ in the follow-up of S. aureus and Gram-negative bacteraemia. In the setting of Gram-negative bacteraemia SeptiScore demonstrated a good negative predictive value for the outcomes of interest and might help rule out the persistence of infection defined as metastatic spread, lack of source control or persistent bacteraemia.