Early deaths in bloodstream infections: a population-based case series

Early deaths associated with community-acquired and healthcare-associated bloodstream infections: a population-based study, Finland, 2004 to 2018

Background

Bloodstream infections (BSI) cause substantial morbidity and mortality.

Aim

We explored the role of causative pathogens and patient characteristics on the outcome of community-acquired (CA) and healthcare-associated (HA) BSI, with particular interest in early death.

Methods

We used national register data to identify all BSI in Finland during 2004–18. We determined the origin of BSI, patients´ underlying comorbidities and deaths within 2 or 30 days from specimen collection. A time-dependent Cox model was applied to evaluate the impact of patient characteristics and causative pathogens on the hazard for death at different time points.

Results

A total of 173,715 BSI were identified; 22,474 (12.9%) were fatal within 30 days and, of these, 6,392 (28.4%) occurred within 2 days (7.9 deaths/100,000 population). The 2-day case fatality rate of HA-BSI was higher than that of CA-BSI (5.4% vs 3.0%). Patients who died within 2 days were older than those alive on day 3 (76 vs 70 years) and had more severe comorbidities. Compared with other BSI, infections leading to death within 2 days were more often polymicrobial (11.8% vs 6.3%) and caused by Pseudomonas aeruginosa (6.2% vs 2.0%), fungi (2.9% vs 1.4%) and multidrug-resistant (MDR) pathogens (2.2% vs 1.8%), which were also predictors of death within 2 days in the model.

Conclusions

Overrepresentation of polymicrobial, fungal, P. aeruginosa and MDR aetiology among BSI leading to early death is challenging concerning the initial antimicrobial treatment. Our findings highlight the need for active prevention and prompt recognition of BSI and appropriate antimicrobial treatment.

Population-Based Study of Bloodstream Infection Incidence and Mortality Rates, Finland, 2004-2018

A 2-fold increase in incidence and death during this period emphasizes the need for additional prevention efforts.

We evaluated the incidence, outcomes, and causative agents of bloodstream infections (BSI) in Finland during 2004–2018 by using data from the national registries. We identified a total of 173,715 BSIs; annual incidence increased from 150 to 309 cases/100,000 population. BSI incidence rose most sharply among persons >80 years of age. The 1-month case-fatality rate decreased from 13.0% to 12.6%, but the 1-month all-cause mortality rate rose from 20 to 39 deaths/100,000 population. BSIs caused by Escherichia coli increased from 26% to 30% of all BSIs. BSIs caused by multidrug-resistant microbes rose from 0.4% to 2.8%, mostly caused by extended-spectrum β-lactamase-producing E. coli. We observed an increase in community-acquired BSIs, from 67% to 78%. The proportion of patients with severe underlying conditions rose from 14% to 23%. Additional public health and healthcare prevention efforts are needed to curb the increasing trend in community-acquired BSIs and antimicrobial drug–resistant E. coli.

Staphylococcus aureus Bacteremia in Patients Infected With COVID-19: A Case Series

Background

Previous viral pandemics have shown that secondary bacterial infections result in higher morbidity and mortality, with Staphylococcus aureus being the primary causative pathogen. The impact of secondary S. aureus bacteremia on mortality in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unknown.

Methods

This was a retrospective observational case series of patients with coronavirus disease 2019 (COVID-19) who developed secondary S. aureus bacteremia across 2 New York City hospitals. The primary end point was to describe 14-day and 30-day hospital mortality rates of patients with COVID-19 and S. aureus bacteremia. Secondary end points included predictors of 14-day and 30-day hospital mortality in patients with COVID-19 and S. aureus bacteremia.

Results

A total of 42 patients hospitalized for COVID-19 with secondary S. aureus bacteremia were identified. Of these patients, 23 (54.8%) and 28 (66.7%) died at 14 days and 30 days, respectively, from their first positive blood culture. Multivariate analysis identified hospital-onset bacteremia (≥4 days from date of admission) and age as significant predictors of 14-day hospital mortality and Pitt bacteremia score as a significant predictor of 30-day hospital mortality (odds ratio [OR], 11.9; 95% CI, 2.03-114.7; P = .01; OR, 1.10; 95% CI, 1.03-1.20; P = .02; and OR, 1.56; 95% CI, 1.19-2.18; P = .003, respectively).

Conclusions

Bacteremia with S. aureus is associated with high mortality rates in patients hospitalized with COVID-19. Further investigation is warranted to understand the impact of COVID-19 and secondary S. aureus bacteremia.

Streptococci and the complement system: interplay during infection, inflammation and autoimmunity

Streptococci are a broad group of Gram-positive bacteria. This genus includes various human pathogens causing significant morbidity and mortality. Two of the most important human pathogens are Streptococcus pneumoniae (pneumococcus) and Streptococcus pyogenes (group A streptococcus or GAS). Streptococcal pathogens have evolved to express virulence factors that enable them to evade complement-mediated attack. These include factor H-binding M (S. pyogenes) and pneumococcal surface protein C (PspC) (S. pneumoniae) proteins. In addition, S. pyogenes and S. pneumoniae express cytolysins (streptolysin and pneumolysin), which are able to destroy host cells. Sometimes, the interplay between streptococci, the complement, and antistreptococcal immunity may lead to an excessive inflammatory response or autoimmune disease. Understanding the fundamental role of the complement system in microbial clearance and the bacterial escape mechanisms is of paramount importance for understanding microbial virulence, in general, and, the conversion of commensals to pathogens, more specifically. Such insights may help to identify novel antibiotic and vaccine targets in bacterial pathogens to counter their growing resistance to commonly used antibiotics.

Mortality after Delay of Adequate Empiric Antimicrobial Treatment of Bloodstream Infection

BACKGROUND

Timely empiric antimicrobial therapy is one of the cornerstones of the management of suspected bloodstream infection (BSI). However, studies about the effects of empiric therapy on mortality have reported inconsistent results. The objective of this study was to estimate the effect of delay of appropriate empiric therapy on early mortality in patients with BSI. Methods: Data for the propensity score matching (PSM) study were obtained from a cohort of patients with BSI. Inadequate empiric treatment was defined as in vitro resistance to the antimicrobial regimen administered <6 h after blood cultures were taken. The primary outcome measure was 14-day mortality. Thirty-day mortality and median length of stay (LOS) were secondary outcomes. PSM was applied to control for confounding. Results: Of a total of 893 included patients with BSI, 35.7% received inadequate initial empiric treatment. In the PSM cohort (n = 334), 14-day mortality was 9.6% for inadequate antibiotic treatment, compared to. 10.2% in adequate empiric treatment (p = 0.85). No prolonged median LOS was observed in patients who initially received inadequate therapy (10.5 vs. 10.7 days, p = 0.89). Conclusions: In this study, we found no clear effect of inadequate empirical treatment on mortality in a low-risk BSI population. The importance of early empiric therapy compared to other determinants, may be limited. This may not apply for specific subpopulations, e.g., patients with sepsis.

Real-Time Monitoring of Bacteria Clearance From Blood in a Murine Model

Bloodstream infections, especially those that are antibiotic resistant, pose a significant challenge to health care leading to increased hospitalization time and patient mortality. There are different facets to this problem that make these diseases difficult to treat, such as the difficulty to detect bacteria in the blood and the poorly understood mechanism of bacterial invasion into and out of the circulatory system. However, little progress has been made in developing techniques to study bacteria dynamics in the bloodstream. Here, we present a new approach using an in vivo flow cytometry platform for real-time, noninvasive, label-free, and quantitative monitoring of the lifespan of green fluorescent protein-expressing Staphylococcus aureus and Pseudomonas aeruginosa in a murine model. We report a relatively fast average rate of clearance for S. aureus (k = 0.37 ± 0.09 min^-1 , half-life ~1.9 min) and a slower rate for P. aeruginosa (k = 0.07 ± 0.02 min^-1 , half-life ~9.6 min). We also observed what appears to be two stages of clearance for S. aureus, while P. aeruginosa appeared only to have a single stage of clearance. Our results demonstrate that an advanced research tool can be used for studying the dynamics of bacteria cells directly in the bloodstream, providing insight into the progression of infectious diseases in circulation. © 2019 International Society for Advancement of Cytometry.

Burden of bacterial bloodstream infection-a brief update on epidemiology and significance of multidrug-resistant pathogens

BACKGROUND

Bloodstream infections comprise a wide variety of pathogens and clinical syndromes with considerable overlap with similar syndromes of non-bacteraemic infections and diverse risk factors, therapeutic implications and outcomes. Yet, this heterogeneous 'entity' has the advantage to be pathogen-defined compared with the broad and even more heterogeneous entity 'sepsis', and so has become helpful for clinicians and epidemiologists for research and surveillance purposes. The increasing availability of population-based and large multicentre well-defined cohort studies should allow us to assess with much confidence and in detail its burden, the significance of antimicrobial resistance, and areas of uncertainty regarding further epidemiological evolution and optimized treatment regimens.

AIM

To review key aspects of bloodstream infection epidemiology and burden, and summarize recent news and questions concerning critical developments.

SOURCES

Peer-reviewed articles based on the search terms 'bloodstream infection' and 'bacteremia' combined with the terms 'epidemiology' and 'burden'. The emphasis was on new information from studies in adult patients and on the added burden due to pathogen resistance to first- and second-line antimicrobial agents.

CONTENT

Topics covered include recent developments in the epidemiology of bloodstream infection due to key pathogens and published information about the relevance of resistance for patient outcomes.

IMPLICATIONS

Despite the availability of population-based studies and an increasing number of large well-defined multicentre cohort studies, more surveillance and systematic data on bloodstream infection epidemiology at regional level and in resource-limited settings may be needed to better design new methods for prevention and define the need for and further develop optimized therapeutic strategies.

Visualizing Infection Surveillance Data for Policymaking Using Open Source Dashboarding

BACKGROUND

Health care-associated infections, specifically catheter-associated urinary tract infections (CAUTIs), can cause significant mortality and morbidity. However, the process of collecting CAUTI surveillance data, storing it, and visualizing the data to inform health policy has been fraught with challenges.

OBJECTIVES

No standard has been developed, so the objective of this article is to present a prototype solution for dashboarding public health surveillance data based on a real-life use-case for the purposes of enhancing clinical and policy-level decision-making.

METHODS

The solution was developed in open source software R, which allows for the creation of dashboard applications using the integrated development environment developed for R called RStudio, and a package for R called Rshiny. How the surveillance system was designed, why R was chosen, how the dashboard was developed, and how the dashboard features were programmed and function will be described.

RESULTS

The prototype dashboard includes multiple tabs for visualizing data, and allows the user to interact with the data by setting dynamic filters. Controls were used to facilitate the interaction between the user and application. Rshiny is reactive, in that when the user (e.g., clinician or policymaker) changes the parameters on the data, the application automatically updates the visualization as well as parameters available based on current filters.

CONCLUSION

The prototype dashboard has the potential to enhance clinical and policy-level decision-making because it facilitates interaction with the data that provides useful visualizations to provide such guidance.

Complement depletion and Coombs positivity in pneumococcal hemolytic uremic syndrome (pnHUS). Case series and plea to revisit an old pathogenetic concept

Hemolytic uremic syndrome is a rare complication of invasive pneumococcal infection (pnHUS). Its pathogenesis is poorly understood, and treatment remains controversial. The emerging role of complement in various forms of HUS warrants a new look at this "old" disease. We performed a retrospective analysis of clinical and laboratory features of three sequential cases of pnHUS since 2008 associated with pneumonia/pleural empyema, two due to Streptococcus pneumoniae serotype 19 A. Profound depletion of complement C3 (and less of C4) was observed in two patients. One patient was Coombs test positive. Her red blood cells (RBCs) strongly agglutinated with blood group compatible donor serum at 0 °C, but not at 37 °C. All three patients were treated with hemodialysis, concentrated RBCs, and platelets. Patient 2 received frozen plasma for hepatic failure with coagulation factor depletion. Intravenous immunoglobulin infusion, intended to neutralize pneumococcal neuraminidase in patient 3, was associated with rapid normalization of platelets and cessation of hemolysis. Two patients recovered without sequelae or disease recurrence. Patient 2 died within 2½ days of admission due to complicating Pseudomonas aeruginosa sepsis and multiorgan failure. Our observations suggest that pnHUS can be associated with dramatic, transient complement consumption early in the course of the disease, probably via the alternative pathway. A critical review of the literature and the reported cases argue against the postulated pathological role of preformed antibodies against the neuraminidase-exposed Thomsen-Friedenreich neoantigen (T antigen) in pnHUS. The improved understanding of complement regulation and bacterial strategies of complement evasion allows to propose a testable, new pathogenetic model of pnHUS. This model shifts emphasis from the action of natural anti-T antibodies toward impaired Complement Factor H (CFH) binding and function on desialylated membranes. Removal of neuraminic acid residues converts (protected) self to non-self surfaces that supports membrane attack complex (MAC) assembly. Complement activation is potentially exacerbated by decreased CFH availability following tight CFH binding to pneumococcal evasion proteins and/or by the presence of genetic variants of complement regulator proteins. Detailed clinical and experimental investigations are warranted to better understand the role of unregulated complement activation in pnHUS. Instead of avoidance of plasma, a new, integrated model is evolving, which may include short-term therapeutic complement blockade, particularly where genetic or functional APC dysregulation is suspected, in addition to bacterial elimination and, potentially, neuraminidase neutralization.

The outcome and timing of death of 17,767 nosocomial bloodstream infections in acute care hospitals in Finland during 1999-2014

Few studies covering all patient groups and specialties are available regarding the outcome of nosocomial bloodstream infections (BSI). We analyzed the role of patient characteristics and causative pathogens of nosocomial BSIs reported by the hospitals participating in national surveillance in Finland during 1999-2014, in terms of outcome, with particular interest in those leading to death within 2 days (i.e. early death). National nosocomial BSI surveillance was laboratory-based and hospital-wide. Data on nosocomial BSIs was collected by infection control nurses, and dates of death were obtained from the national population registry with linkage to national identity codes. A total of 17,767 nosocomial BSIs were identified; 557 BSIs (3%) were fatal within 2 days and 1150 (6%) within 1 week. The 1-month case fatality was 14% (2460 BSIs), and 23% of the deaths occurred within 2 days and 47% within 1 week. The patients who died early were older than those who survived > 28 days, and their BSIs were more often related to intensive care. Gram-positive bacteria caused over half of the BSIs of patients who survived, whereas gram-negative bacteria, especially Pseudomonas aeruginosa, caused more often BSIs of patients who died early, and fungi BSIs of patients who died within 1 week. A significant portion of patients with nosocomial BSIs died early, which underlines the importance of rapid recognition of BSI. Hospital-wide surveillance data of causative pathogens can be utilized when composing recommendations for empiric antimicrobial treatment in collaboration with clinicians, as well as when promoting infection prevention.

Prevalence and risk factors for bloodstream infection present on hospital admission

BACKGROUND

Bloodstream infection present on hospital admission (BSI-POA) is a major cause of morbidity and mortality. The purpose of this study was to measure prevalence and describe the risk factors of patients with BSI-POA and to determine the prevalence of resistance in isolates by admission source.

METHODS

We conducted a retrospective cohort study of patients discharged from three hospitals in New York City between 2006 and 2014. BSI-POA was defined as BSI diagnosed within 48 h of hospitalisation.

RESULTS

The prevalence for BSI-POA was 5307/315,010 discharges (1.7%). The odds of being admitted with BSI-POA were greatest among patients admitted with renal failure, chronic dermatitis, malignancies and prior hospitalisation. Odds ratios and 95% confidence intervals (CI) were 2.72 (95% CI = 2.56-2.88), 2.15 (95% CI = 1.97-2.34), 1.76 (95% CI = 1.64-1.88) and 1.59 (95% CI = 1.50-1.69), respectively. The largest proportion of BSI-POA presented with Staphylococcus aureus (48.4%), followed by Enterococcus faecalis/faecium (20.3%), Klebsiella pneumoniae (16.2%), Streptococcus pneumoniae (8.7%), Pseudomonas aeruginosa (4.2%) and Acinetobacter baumannii (2.2%). Overall, 44% of those admitted from nursing homes presented with antibiotic resistant strains versus 34% from other hospitals and 31% from private homes (P = 0.002).

CONCLUSION

Understanding the risk factors of patients who present to the hospital with BSI could enable timely interventions and better patient outcomes.