Bloodstream infection clusters for critically ill patients: analysis of two-center retrospective cohorts

BACKGROUND

Bloodstream infections (BSI) are highly prevalent in hospitalized patients requiring intensive care. They are among the most serious infections and are highly associated with sepsis or septic shock, which can lead to prolonged hospital stays and high healthcare costs. This study aimed at establishing an easy-to-use nomogram for predicting the prognosis of patients with BSI.

METHODS

In retrospective study, records of patients with BSI admitted to the intensive care unit (ICU) over the period from Jan 1st 2016 to Dec 31st 2021 were included. We used data from two different China hospitals as development cohort and validation cohort respectively. The demographic and clinical data of patients were collected. Based on all baseline data, k-means algorithm was applied to discover the groups of BSI phenotypes with different prognostic outcomes, which was confirmed by Kaplan-Meier analysis and compared using log-rank tests. Univariate Cox regression analyses were used to estimate the risk of clusters. Random forest was used to identified discriminative predictors in clusters, which were utilized to construct nomogram based on multivariable logistic regression in the discovery cohort. For easy clinical applications, we developed a bloodstream infections clustering (BSIC) score according to the nomogram. The results were validated in the validation cohort over a similar period.

RESULTS

A total of 360 patients in the discovery cohort and 310 patients in the validation cohort were included in statistical analyses. Based on baseline variables, two distinct clusters with differing prognostic outcomes were identified in the discovery cohort. Population in cluster 1 was 211 with a ICU mortality of 17.1%, while population in cluster 2 was 149 with an ICU mortality of 41.6% (p < 0.001). The survival analysis also revealed a higher risk of death for cluster 2 when compared with cluster 1 (hazard ratio: 2.31 [95% CI, 1.53 to 3.51], p < 0.001), which was confirmed in validation cohort. Four independent predictors (vasoconstrictor use before BSI, mechanical ventilation (MV) before BSI, Deep vein catheterization (DVC) before BSI, and antibiotic use before BSI) were identified and used to develop a nomogram. The nomogram and BSIC score showed good discrimination with AUC of 0.96.

CONCLUSION

The developed score has potential applications in the identification of high-risk critically ill BSI patients.

Extended-Spectrum β-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae: Risk Factors and Economic Burden Among Patients with Bloodstream Infections

Introduction

Although Extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EK) significantly contribute to bloodstream infections, their economic repercussions remain largely unquantified.

Data Source and Methods

We performed a retrospective analysis of inpatients diagnosed with Escherichia coli or Klebsiella pneumoniae bacteremia in a tertiary hospital from January 2020 to December 2022 in Guangzhou, China. We employed the chi-square test to examine ESBL risk factors and utilized propensity score matching (PSM) to negate baseline confounding factors, assessing economic burden through disability-adjusted life years (DALYs), hospital costs and productivity losses. We employed mediation analysis to eliminate confounding factors and better identify ESBL sources of burden related.

Results

We found 166 ESBL-EC/KP BSI patients (52.2% of the total examined 318 patients). Post-PSM analysis revealed that ESBL-producing EC/KP will reduce the effectiveness of empirical medication by 19.8%, extend the total length of hospitalization by an average of 3 days, and increase the patient's financial burden by US$2047. No significant disparity was found in overall mortality and mean DALYs between the groups. Mediation analysis showed that the link between ESBL and hospital costs is predominantly, if not entirely, influenced by the appropriateness of empirical antibiotic treatment and length of hospital stay.

Conclusion

Patients with BSI due to ESBL-producing ESBL-EK incur higher costs compared to those with non-ESBL-EK BSI. This cost disparity is rooted in varying rates of effective empirical antimicrobial therapy and differences in hospital stay durations. A nuanced approach, incorporating a thorough understanding of regional epidemiological trends and judicious antibiotic use, is crucial for mitigating the financial impact on patients.

Association Between Vancomycin AUC and Clinical Failure in Patients with Streptococcal Bacteremia

Background: Monitoring of vancomycin using the area under the curve (AUC) to minimum inhibitory concentration (MIC) ratio is now preferred for serious methicillin-resistant Staphylococcus aureus infections. Vancomycin AUC/MIC monitoring is being investigated but is not yet well elucidated with other bacterial pathogens. Methods: A retrospective cross-sectional study was conducted assessing patients with streptococcal bacteremia treated with vancomycin definitive therapy. AUC was calculated using a Bayesian approach, and classification and regression tree analysis was used to identify a vancomycin AUC threshold predictive of clinical failure. Results: Eleven patients had a vancomycin AUC < 329 of which 8 (73%) experienced clinical failure, while 35 patients had a vancomycin AUC ≥ 329 of which 12 (34%) experienced clinical failure (P = .04). Hospital length of stay was longer in the AUC ≥ 329 group (15 vs 8 days, P = .05), whereas time to bacteremia clearance (29 [22-45] vs 25 [20-29] hours, P = .15) and toxicity incidence (13% vs 4%, P = 1) were similar between groups. Conclusions: This study identified a VAN AUC threshold of <329 to be predictive of clinical failure in patients with streptococcal bacteremia which should be interpreted as hypothesis-generating. Studies evaluating VAN AUC-based monitoring for streptococcal bloodstream infections along with other infection types are needed before implementation into clinical practice can be recommended.

All Staphylococcus aureus bacteraemia-inducing strains can cause infective endocarditis: Results of GWAS and experimental animal studies

OBJECTIVES

We aimed at determining whether specific S. aureus strains cause infective endocarditis (IE) in the course of Staphylococcus aureus bacteraemia (SAB).

METHODS

A genome-wide association study (GWAS) including 924 S. aureus genomes from IE (274) and non-IE (650) SAB patients from international cohorts was conducted, and a subset of strains was tested with two experimental animal models of IE, one investigating the early step of bacterial adhesion to inflamed mice valves, the second evaluating the local and systemic developmental process of IE on mechanically-damaged rabbit valves.

RESULTS

The genetic profile of S. aureus IE and non-IE SAB strains did not differ when considering single nucleotide polymorphisms, coding sequences, and k-mers analysed in GWAS. In the murine inflammation-induced IE model, no difference was observed between IE and non-IE SAB strains both in terms of adhesion to the cardiac valves and in the propensity to cause IE; in the mechanical IE-induced rabbit model, there was no difference between IE and non-IE SAB strains regarding the vegetation size and CFU.

CONCLUSION

All strains of S. aureus isolated from SAB patients must be considered as capable of causing this common and lethal infection once they have accessed the bloodstream.

Staphylococcus aureus bacteraemia and mortality: a population-based study in Olmsted County, Minnesota, from 2006 to 2020

OBJECTIVES

To provide an evaluation of predictors of 6-month mortality in incident Staphylococcus aureus bacteraemia cases.

METHODS

A retrospective population-based study of 541 adult residents of Olmsted County, MN with monomicrobial S. aureus bacteraemia from 1 January 2006 through 31 December 2020. Multivariable Cox regression was used to investigate risk factors of 6-month mortality.

RESULTS

The median (interquartile range [IQR]) age of 541 patients with S. aureus bacteraemia was 66.8 (54.4-78.5) years and 39.6% were female. The median (IQR) Charlson Comorbidity Index was 6 (3-9). Overall, 144 patients died during the six-month period following their initial episode (30-day and 6-month mortality = 16.5% and 26.7%, respectively). In a multivariable analysis, older age, ICU admission, and unknown source of infection were significant predictors of increased 6-month mortality. In contrast, having an infectious diseases (ID) consultation was associated with reduced mortality in the first 2 weeks of follow-up. Secondary analyses revealed an early benefit of ID consultation during the first 30 days of follow-up and that infective endocarditis was an additional predictor of 6-month mortality.

CONCLUSIONS

To our knowledge, this investigation represents the only US population-based study evaluating predictors of mortality in patients with S. aureus bacteraemia. The finding of a short-term survival benefit associated with early ID consultation may be due to more extensive diagnostic efforts.

Streptavidin Fe2O3-gold nanoparticles functionalized theranostic liposome for antibiotic resistant bacteria and biotin sensing

Novel methods of sensing and treatment required to elicit potent humoral and cellular immune responses. Here, Streptavidin functionalized α-Fe2O3-Au nanoparticles (STV-Mag) loaded cationic carbomate cholesterol is used as a carrier to release antibacterial thymol drug for Staphylococcus aureus (S. aureus) infected Caenorhabditis elegans (C. elegans). Pertaining to theranostic applications, efficient antimicrobial activity, and non-stimulated drug release and biotin dependent S. aureus growth were studied in-vivo. While STV-Mag was tethered on mercaptobenzoic acid (MBA) molecular cushion for label free streptavidin-biotin electrochemical sensing, the STV-Mag-carbomate cholesterol (STV-Mag-cCHOL liposome) vesicle with loaded drug was tethered on MBA for non-stimulant drug release through specific cholesterol-S. aureus interaction and confirmed electrochemically. Selectivity was confirmed using other pathogens, E. coli, Proteus and Enterococcus bacterium through antimicrobial studies along with S. aureus. The biotin sensing showed linear range from 10-15 to 10-3 M, which was not obtained by conventional methods. Fourier-Transform Infra-red (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques were used to characterize the nanoparticulate system.

Intravenous to oral transition of antibiotics for gram-negative bloodstream infection at a University hospital in Thailand: Clinical outcomes and predictors of treatment failure

Background

Limited studies evaluate the outcome of intravenous antibiotics to oral transition in Gram-negative bloodstream infection (GN-BSI), particularly GN-BSI originating outside the urinary tract. This study aimed to evaluate treatment success in patients with GN-BSI treated with either intravenous therapy or intravenous to oral transition and to identify factors associated with treatment failure in those undergoing intravenous to oral transition.

Methods

A retrospective cohort study was conducted at King Chulalongkorn Memorial Hospital, Thailand. Patients were included if they were ≥18 years of age, hospitalized in general medical wards with GN-BSI between August 1, 2015, to July 31, 2020, received intravenous antibiotic agents and had a functioning gastrointestinal tract.

Results

Of 955 patients, 545 (57.1%) were in the intravenous to oral transition group. The urinary tract was the most common source of infection (38.8%). Ciprofloxacin was the most prescribed oral antibiotic (53%). Treatment success occurred in 94.3% in the intravenous antibiotic to oral transition group. There was no significant difference in treatment success between the two groups (P = 0.790) with a concordant result after using propensity score matching (P = 0.223). Independent predictors of treatment failure in the intravenous to oral transition group included metastatic solid cancer (aOR = 4.355), HIV infection with CD₄ < 200 cells/mm³ (aOR = 8.452), qSOFA score ≥ 2 (aOR = 2.545), multidrug-resistant infection (aOR = 2.849), and respiratory tract infection (aOR = 8.447). Hospital length of stay in the intravenous to oral transition group was shorter than in the intravenous group (P < 0.001).

Conclusions

Intravenous to oral transition may be a practical approach in GN-BSI. Patients with Gram-negative bacteremia who have HIV infection with CD₄ < 200 cells/mm³, multidrug-resistant infections, and respiratory tract sources of infection may not be ideal candidates for this approach. Future research is needed from a randomized controlled trial.

Worsening Glycemia Increases the Odds of Intermittent but Not Persistent Staphylococcus aureus Nasal Carriage in Two Cohorts of Mexican American Adults

Numerous host and environmental factors contribute to persistent and intermittent nasal Staphylococcus aureus carriage in humans. The effects of worsening glycemia on the odds of S. aureus intermittent and persistent nasal carriage was established in two cohorts from an adult Mexican American population living in Starr County, Texas. The anterior nares were sampled at two time points and the presence of S. aureus determined by laboratory culture and spa-typing. Persistent carriers were defined by the presence of S. aureus of the same spa-type at both time points, intermittent carriers were S. aureus-positive for 1 of 2 swabs, and noncarriers were negative for S. aureus at both time points. Diabetes status was obtained through personal interview and physical examination that included a blood draw for the determination of percent glycated hemoglobin A1c (%HbA1c), fasting plasma glucose, and other blood chemistry values. Using logistic regression and general estimating equations, the odds of persistent and intermittent nasal carriage compared to noncarriers across the glycemic spectrum was determined controlling for covariates. Increasing fasting plasma glucose and %HbA1c in the primary and replication cohort, respectively, were significantly associated with increasing odds of S. aureus intermittent, but not persistent nasal carriage. These data suggest that increasing dysglycemia is a risk factor for intermittent S. aureus nasal carriage potentially placing those with poorly controlled diabetes at an increased risk of acquiring an S. aureus infection. IMPORTANCE Factors affecting nasal S. aureus colonization have been studied primarily in the context of persistent carriage. In contrast, few studies have examined factors affecting intermittent nasal carriage with this pathogen. This study demonstrates that the odds of intermittent but not persistent nasal carriage of S. aureus significantly increases with worsening measures of dysglycemia. This is important in the context of poorly controlled diabetes since the risk of becoming colonized with one of the primary organisms associated with diabetic foot infections can lead to increased morbidity and mortality.

The Role of the Oral Immune System in Oropharyngeal Candidiasis-Facilitated Invasion and Dissemination of Staphylococcus aureus

Candida albicans and Staphylococcus aureus account for most invasive fungal and bacterial bloodstream infections (BSIs), respectively. However, the initial point of invasion responsible for S. aureus BSIs is often unclear. Recently, C. albicans has been proposed to mediate S. aureus invasion of immunocompromised hosts during co-colonization of oral mucosal surfaces. The status of the oral immune system crucially contributes to this process in two distinct ways: firstly, by allowing invasive C. albicans growth during dysfunction of extra-epithelial immunity, and secondly following invasion by some remaining function of intra-epithelial immunity. Immunocompromised individuals at risk of developing invasive oral C. albicans infections could, therefore, also be at risk of contracting concordant S. aureus BSIs. Considering the crucial contribution of both oral immune function and dysfunction, the aim of this review is to provide an overview of relevant aspects of intra and extra-epithelial oral immunity and discuss predominant immune deficiencies expected to facilitate C. albicans induced S. aureus BSIs.

Impact of neutropenia on clinical manifestations and outcome of Staphylococcus aureus bloodstream infection - A propensity score-based overlap weight analysis in two large, prospectively evaluated cohorts

OBJECTIVE

To investigate whether neutropenia influenced mortality and long-term outcome of Staphylococcus aureus bloodstream infection (SAB).

METHODS

Data from two prospective, multicentre cohort studies (INSTINCT and ISAC) conducted in 20 tertiary care hospitals in 6 countries between 2006 and 2015 were analysed. Neutropenic and severely neutropenic patients (defined by the proxy of total white blood cell count <1000/μl and <500/μl, respectively, at onset of SAB) were compared to a control group using a propensity score model and overlap weights to adjust for baseline characteristics. Overall survival and time to SAB-related late complications (SAB recurrence, infective endocarditis, osteomyelitis, or other deep-seated manifestations) were analysed by Cox regression and competing risk analyses, respectively.

RESULTS

Of 3,187 patients, 102 were neutropenic and 70 were severely neutropenic at onset of SAB. Applying overlap weights yielded two groups of 83 neutropenic and 220 non-neutropenic patients, respectively. Baseline characteristics of these groups were exactly balanced. In the Cox regression analysis, we observed no significant difference in survival between the two groups (death during follow-up: 36.1 % in neutropenic vs. 30.6 % in non-neutropenic patients, hazard ratio 1.21 (95 % CI 0.79-1.83)). This finding remained unchanged when we considered severely neutropenic patients (hazard ratio 1.08 [0.60; 1.94]). Competing risk analysis showed a cause-specific hazard ratio (CSHR) of 0.39 (95 % CI 0.11-1.39) for SAB-related late-complications in neutropenic patients.

CONCLUSIONS

Neutropenia was not associated with a higher survival during follow-up. The lower rate of SAB-related late complications in neutropenic patients should be validated in other cohorts.

Evaluation of step-down oral antibiotic therapy for uncomplicated streptococcal bloodstream infections on clinical outcomes

Background:

Despite the severity and frequency of streptococcal bloodstream infections (BSIs), the effectiveness of oral definitive therapy remains unknown. The objective of this study was to evaluate the clinical outcomes of step-down oral antibiotics for the treatment of uncomplicated streptococcal BSIs.

Methods:

In this retrospective cohort study, adult patients admitted with uncomplicated streptococcal BSI between June 2015 and June 2017 were included. Patients were excluded if they received <48 h of antibiotic therapy; therapy was started >48 h after first positive culture; had complicated infections of endocarditis, bone and joint infections, or central nervous system infections; Pitt bacteremia score (PBS) ⩾ 4; or failed to respond to effective therapy necessitating continued intravenous (IV) therapy. Patients were grouped by receipt of step-down oral antibiotic therapy (PO group) versus continued IV therapy (IV group). Outcomes included hospital length of stay (LOS), 30-day recurrence of BSI, 30-day readmission, 30-day all-cause mortality, and catheter-related or drug-related adverse events (AEs).

Results:

Of 244 patients included, 40% received step-down oral therapy (n = 98). Overall, the most common source of BSI was pneumonia (22%), followed by skin and soft tissue infections (SSTI) (18%). Severity of illness measured by intensive care unit (ICU) admission and PBS was similar. The IV group had significantly longer LOS [median 10 (interquartile range [IQR] = 5–21) versus 5 (4–6) days, p < 0.01] compared with the PO group. BSI recurrence, readmission, all-cause mortality within 30 days, and AEs were similar between the groups (p = ns).

Conclusion:

In uncomplicated streptococcal BSI, patients treated with step-down oral antibiotic therapy had significantly shorter LOS compared with continued IV therapy without compromise of clinical outcomes.

Clindamycin Efficacy in Patients With Methicillin-Sensitive Staphylococcus aureus in a Fourth-Level Hospital in the City of Medellín

Background: The antibiotic of choice for methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia is antistaphylococcal penicillins, such as oxacillin, but cefazolin has also risen as an equally effective alternative. Murine models have suggested that clindamycin is a therapeutic alternative for Staphylococcus aureus bacteremia (SAB).

Methods: In this retrospective cohort study, patients from the Hospital Universitario San Vicente Fundación (HUSVF) in Medellín, Colombia, were recruited from January 2013 and December 2019. Patients with positive blood culture for MSSA, with at least one follow-up blood culture, and those with more than 72 hours of parenteral antibiotic therapy for SAB were selected. The main objective was to determine the efficacy of clindamycin compared to other antibiotics to achieve a microbiologic cure. Secondary results included in-hospital mortality and hospital stay.

Results: A total of 486 patients were included (clindamycin = 50 and other anti-MSSA = 436). The patients in the clindamycin group had a lower rate of microbiological cure (n = 41 [84%]) compared to other antibiotics (n = 367 [84%]) (OR 1.08 IC 95% 0.74-1.58). In secondary outcomes, no statistically significant differences were observed in the in-hospital mortality. The main source of SAB was a central or peripheral catheter (58%).

Conclusions: Our study found no differences in the rate of microbiological cure, in-hospital mortality, and hospital stay on the clindamycin group compared to other anti-MSSA antibiotics. However, in patients with metastatic complications, the rate of microbiological cure is reduced, and the in-hospital mortality is higher in patients with more severe disease.

Impact of Immunosuppressive Agents on Clinical Manifestations and Outcome of Staphylococcus aureus Bloodstream Infection: A Propensity Score-Matched Analysis in 2 Large, Prospectively Evaluated Cohorts

BACKGROUND

Staphylococcus aureus bloodstream infection (SAB) is a common, life-threatening infection. The impact of immunosuppressive agents on the outcome of patients with SAB is incompletely understood.

METHODS

Data from 2 large prospective, international, multicenter cohort studies (Invasive Staphylococcus aureus Infections Cohort [INSTINCT] and International Staphylococcus aureus Collaboration [ISAC]) between 2006 and 2015 were analyzed. Patients receiving immunosuppressive agents were identified and a 1:1 propensity score-matched analysis was performed to adjust for baseline characteristics of patients. Overall survival and time to SAB-related late complications (SAB relapse, infective endocarditis, osteomyelitis, or other deep-seated manifestations) were analyzed by Cox regression and competing risk analyses, respectively. This approach was then repeated for specific immunosuppressive agents (corticosteroid monotherapy and immunosuppressive agents other than steroids [IMOTS]).

RESULTS

Of 3188 analyzed patients, 309 were receiving immunosuppressive treatment according to our definitions and were matched to 309 nonimmunosuppressed patients. After propensity score matching, baseline characteristics were well balanced. In the Cox regression analysis, we observed no significant difference in survival between the 2 groups (death during follow-up: 105/309 [33.9%] immunosuppressed vs 94/309 [30.4%] nonimmunosuppressed; hazard ratio [HR], 1.20 [95% confidence interval {CI}, .84-1.71]). Competing risk analysis showed a cause-specific HR of 1.81 (95% CI, .85-3.87) for SAB-related late complications in patients receiving immunosuppressive agents. The cause-specific HR was higher in patients taking IMOTS (3.69 [95% CI, 1.41-9.68]).

CONCLUSIONS

Immunosuppressive agents were not associated with an overall higher mortality. The risk for SAB-related late complications in patients receiving specific immunosuppressive agents such as IMOTS warrants further investigations.

Adjunctive Daptomycin in the Treatment of Methicillin-susceptible Staphylococcus aureus Bacteremia: A Randomized, Controlled Trial

BACKGROUND

Bloodstream infections (BSIs) with methicillin-susceptible Staphylococcus aureus (MSSA) are associated with significant morbidity and mortality. Our objective in this study was to determine the efficacy of synergistic treatment with daptomycin when given with either cefazolin or cloxacillin for the treatment of MSSA BSI.

METHODS

A randomized, double-blind, placebo-controlled trial was performed at 2 academic hospitals in Montreal, Canada. Patients aged ≥18 years with MSSA BSI receiving either cefazolin or cloxacillin monotherapy were considered for inclusion. In addition to the standard-of-care treatment, participants received a 5-day course of adjunctive daptomycin or placebo. The primary outcome was the duration of MSSA BSI in days.

RESULTS

Of 318 participants screened, 115 were enrolled and 104 were included in the intention-to-treat analysis (median age, 67 years; 34.5% female). The median duration of bacteremia was 2.04 days among patients who received daptomycin vs 1.65 days in those who received placebo (absolute difference, 0.39 days; P = .40). In a modified intention-to-treat analysis that involved participants who remained bacteremic at the time of enrollment, we found a median duration of bacteremia of 3.06 days among patients who received daptomycin vs 3.0 days in those who received placebo (absolute difference, 0.06 days; P = .77). Ninety-day mortality in the daptomycin arm was 18.9% vs 17.7% in the placebo arm (P = 1.0).

CONCLUSIONS

Among patients with MSSA BSIs, the administration of adjunctive daptomycin therapy to standard-of-care treatment did not shorten the duration of bacteremia and should not be routinely considered.

CLINICAL TRIALS REGISTRATION

NCT02972983.

Clinical characteristics and outcome of bacteraemia caused by Enterobacter cloacae and Klebsiella aerogenes: more similarities than differences

OBJECTIVES

The genus Enterobacter is a common cause of nosocomial infections. Historically, the most frequent Enterobacter species were those of Enterobacter cloacae complex and Enterobacter aerogenes. In 2019, E. aerogenes was re-classified as Klebsiella aerogenes owing to its higher genotypic similarity with the genus Klebsiella. Our objective was to characterise and compare the clinical profiles of bacteraemia caused by E. cloacae and K. aerogenes.

METHODS

This 3-year multicentre, prospective cohort study enrolled consecutive patients with bacteraemia by E. cloacae or K. aerogenes. Baseline characteristics, bacteraemia features (source, severity, treatment), antibiotic susceptibility, resistance mechanisms and mortality were analysed.

RESULTS

The study included 285 patients with bacteraemia [196 (68.8%) E. cloacae and 89 (31.2%) K. aerogenes]. The groups showed no differences in age, sex, previous use of invasive devices, place of acquisition, sources or severity at onset. The Charlson score was higher among patients with E. cloacae bacteraemia [2 (1-4) vs. 1 (0.5-3); P = 0.018], and previous antibiotic therapy was more common in patients with K. aerogenes bacteraemia (57.3% vs. 41.3%; P = 0.01). Mortality was 19.4% for E. cloacae and 20.2% for K. aerogenes (P = 0.869). Antibiotic susceptibility was similar for both species, and the incidence of multidrug resistance or ESBL production was low (6% and 5.3%, respectively), with no differences between species.

CONCLUSION

Bacteraemias caused by E. cloacae and K. aerogenes share similar patient profiles, presentation and prognosis. Patients with E. cloacae bacteraemia had more co-morbidities and those with K. aerogenes bacteraemia had received more antibiotics.

Distance Between Home and the Admitting Hospital and Its Effect on Survival of Low Socioeconomic Status Population With Staphylococcus aureus Bacteremia

OBJECTIVE

Bacteremia is the presence of bacteria in the bloodstream. The objective of this study was to determine the relationship between low socioeconomic status (SES) and the epidemiology, process of care, and outcomes of patients with Staphylococcus aureus bacteremia (SAB).

METHODS

We conducted a multicenter, retrospective, cohort study that evaluated adult patients with SAB in 3 Los Angeles County hospitals from July 15, 2012, through May 31, 2018. We determined SES (low SES, intermediate SES, and high SES) for each patient and compared sociodemographic and epidemiologic characteristics, management of care received by patients with SAB (ie, process of care), and outcomes. We used a Cox proportional hazards model to determine predictors of 30-day mortality for each SES group.

RESULTS

Of 915 patients included in the sample, 369 (40%) were in the low-SES group, 294 (32%) in the intermediate-SES group, and 252 (28%) in the high-SES group. Most significant predictors of 30-day mortality in the Cox proportional hazards model were admission to an intensive care unit (hazard ratio [HR] = 9.04; 95% CI, 4.26-19.14), Pitt bacteremia score ≥4 indicating critical illness (HR = 4.30; 95% CI, 2.49-7.44), having ≥3 comorbidities (HR = 2.05; 95% CI, 1.09-3.85), and advanced age (HR = 1.03; 95% CI, 1.01-1.05). Distance between home and admitting hospital affected mortality only in the low-SES group (HR = 1.02; 95% CI, 1.00-1.02).

CONCLUSIONS

SES did not independently affect the outcome of SAB; however, the farther the patient's residence from the hospital, the greater the negative effect on survival in a low-SES population. Our findings underscore the need to develop multipronged, targeted public health efforts for populations that have transportation barriers to health care.

Comparable outcomes of short-course and prolonged-course therapy in selected cases of methicillin-susceptible Staphylococcus aureus bacteremia:A pooled cohort study

BACKGROUND

The recommended duration of antimicrobial treatment for Staphylococcus aureus bacteremia (SAB) is a minimum of 14 days. We compared the clinical outcomes of patients receiving short-course (SC), 6-10 days, or prolonged-course (PC), 10-16 days, antibiotic therapy for low risk methicillin-susceptible SAB (MS-SAB).

METHODS

Adults with MS-SAB in 1995-2018 were included from three independent retrospective cohorts. Logistic regression models fitted with inverse probability of treatment weighting were used to assess the association between the primary outcome of 90-day mortality and treatment duration for the individual cohorts as well as a pooled cohort analysis.

RESULTS

A total of 645, 219 and 141 patients with low risk MS-SAB were included from Cohort I, II and III. Median treatment duration in the three SC groups were 8 days (interquartile range [IQR] 7-10), 9 days (IQR 8-10), and 8 days (IQR 7-10). In the PC groups patients received a median therapy of 14 days (IQR 13-15), 14 days (IQR 13-15) and 13 days (IQR 12-15). No significant differences in 90-day mortality were observed between the SC and PC group in Cohort I (Odds ratio [OR] 0.85, 95% confidence interval [CI] 0.49-1.41), Cohort II (OR 1.24, 95% CI 0.60-2.62) nor Cohort III (OR 1.15, 95% CI 0.24-4.019). This result was consistent in the pooled cohort analysis (OR 1.05, 95% CI 0.71-1.51). Furthermore, duration of therapy was not associated with the risk of relapse.

CONCLUSION

In patients with low risk MS-SAB, shorter courses of antimicrobial therapy yielded similar clinical outcomes compared to longer courses of therapy.

Validation of VIRSTA and Predicting Risk of Endocarditis Using a Clinical Tool (PREDICT) Scores to Determine the Priority of Echocardiography in Patients With Staphylococcus aureus Bacteremia

Background

Infective endocarditis (IE) secondary to Staphylococcus aureus bacteremia (SAB) has high morbidity and mortality. The systematic use of echocardiography in SAB is controversial. We aimed to validate VIRSTA and Predicting Risk of Endocarditis Using a Clinical Tool (PREDICT) scores for predicting the risk of IE in Colombian patients with SAB and, consequently, to determine the need for echocardiography.

Methods

Cohort of patients hospitalized with SAB in 2 high complexity institutions in Medellin, Colombia, between 2012 and 2018. The diagnosis of IE was established based on the modified Duke criteria. The VIRSTA and PREDICT scores were calculated from the clinical records, and their operational performance was calculated.

Results

The final analysis included 922 patients, 62 (6.7%) of whom were diagnosed with IE. The frequency of IE in patients with a negative VIRSTA scale was 0.44% (2/454). The frequency of IE in patients with a negative PREDICT scale on day 5 was 4.8% (30/622). The sensitivity and negative predictive value (NPV) of the VIRSTA scale was 96.7% and 99.5%, respectively. For the PREDICT scale on day 5, the sensitivity and NPV were 51.6% and 95.1%, respectively. The discrimination, given by the area under the receiver operating characteristic curve, was 0.86 for VIRSTA and 0.64 for PREDICT.

Conclusions

In patients with negative VIRSTA, screening echocardiography may be unnecessary because of the low frequency of IE. In PREDICT-negative patients, despite the low frequency of IE, it is not safe to omit echocardiography.

Reduction of 30-day death rates from Staphylococcus aureus bacteremia by mandatory infectious diseases consultation: Comparative study interventions with and without an infectious disease specialist

OBJECTIVES

Most Japanese hospitals need to keep to higher Staphylococcus aureus bacteremia (SAB) quality-of-care indicators (QCIs) and create strategies that can maximize the effect of these QCIs with only a small number of infectious disease specialists. This study aimed to evaluate the clinical outcomes of patients with SAB before and after the enhancement of the mandatory infectious disease consultations (IDCs).

METHODS

This retrospective study was conducted at a tertiary care hospital in Japan. The primary outcome was the 30-day mortality between each period. A generalized structural equation model was employed to examine the effect of the mandatory IDC enhancement on 30-day mortality among patients with SAB.

RESULTS

A total of 114 patients with SAB were analyzed. The 30-day all-cause mortality differed significantly between the two periods (17.3% vs. 4.8%, P = 0.02). Age, three-QCI point ≥ 1, and Pitt bacteremia score ≥ 3 were the significant risk factors for 30-day mortality. The intervention was also significantly associated with improved adherence to QCIs.

CONCLUSION

Mandatory IDCs for SAB improved 30-day mortality and adherence to QCIs after the intervention. In Japan, improving the quality of management in patients with SAB should be an important target.

Toll-like receptor 2 downregulation and cytokine dysregulation predict mortality in patients with Staphylococcus aureus bacteremia

BACKGROUND

Staphylococcus aureus bacteremia (SAB) presents heterogeneously, owing to the differences in underlying host conditions and immune responses. Although Toll-like receptor 2 (TLR2) is important in recognizing S. aureus, its function during S. aureus infection remains controversial. We aimed to examine the association of TLR2 expression and associated cytokine responses with clinical SAB outcomes.

METHODS

Patients from a prospective SAB cohort at two tertiary-care medical centers were enrolled. Blood was sampled at several timepoints (≤5 d, 6-9 d, 10-13 d, 14-19 d, and ≥ 20 d) after SAB onset. TLR2 mRNA levels were determined via real-time PCR and serum tumor necrosis factor [TNF]-α, interleukin [IL]-6, and IL-10 levels were analyzed with multiplex-high-sensitivity electrochemiluminescent ELISA.

RESULTS

TLR2 levels varied among 59 SAB patients. On days 2-5, TLR2 levels were significantly higher in SAB survivors than in healthy controls (p = 0.040) and slightly but not significantly higher than non-survivors (p = 0.120), and SAB patients dying within 7 d had lower TLR2 levels than survivors (P = 0.077) although statistically insignificant. IL-6 and IL-10 levels were significantly higher in non-survivors than in survivors on days 2-5 post-bacteremia (P = 0.010 and P = 0.021, respectively), and those dying within 7 d of SAB (n = 3) displayed significantly higher IL-10/TNF-α ratios than the survivors did (P = 0.007).

CONCLUSION

TLR2 downregulation and IL-6 and IL-10 concentrations suggestive of immune dysregulation during early bacteremia may be associated with mortality from SAB. TLR2 expression levels and associated cytokine reactions during early-phase SAB may be potential prognostic factors in SAB, although larger studies are warranted.

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.

Economic Burden of Patients with Bloodstream Infections Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli

Background

The prevalence of infections with extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) is increasing worldwide, but the economic impact of ESBL-EC bloodstream infection (BSI) has not been comprehensively evaluated.

Patients and Methods

A retrospective cohort including patients hospitalized at a tertiary hospital between January 2013 and December 2016 who were confirmed with a BSI of ESBL-EC or non-ESBL-EC was set. Clinical data and medical costs were collected by chart review of electronic and paper medical records. The economic burden was evaluated with disability-adjusted life years (DALYs).

Results

A total of 580 patients with E. coli BSI, comprising 333 patients (57.4%) with ESBL-EC BSI and 247 patients (42.6%) with non-ESBL-EC BSI, were identified. There were no significant differences in comorbidity and severity of patients between ESBL-EC and non-ESBL-EC BSI. The median length of stay (LOS) after bacteremia was 12 days for ESBL-EC (interquartile range, 7 to 21) versus 11 days for non-ESBL-EC (interquartile range, 7 to 21) (P = 0.38), and appropriate empirical antimicrobial therapy occurred in 87.4% versus 89.9% (P = 0.353). The mortalities were 20.1% versus 17.4% (P = 0.41). Patients with ESBL-EC did not have significantly different in-hospital medical costs to those with non-ESBL-EC (median, $8048.68 vs $7476.84, respectively, with a difference of $571.84, P = 0.321). In the non-ESBL-EC group, 247 patients lost 531.05 DALYs in total, with an average of 2.15 DALYs per person, while in the ESBL-EC group, 333 patients lost 692.64 DALYs in total, with an average of 2.08 DALYs per person. There is no significant difference in average DALYs (P = 0.343).

Conclusion

In conclusion, patients with BSI due to ESBL-EC did not cost more than patients with BSI due to non-ESBL-EC. This phenomenon may be attributed to timely and effective antibiotic treatment, but the initial empiric therapy with second- or third-line antibiotics in non-ESBL-EC BSI should be corrected.

Assessing the impact of a 'bundle of care' approach to Staphylococcus aureus bacteraemia in a tertiary hospital

Background

Staphylococcus aureus bacteraemia is associated with significant morbidity and mortality. There is evidence that standardised care bundle implementation may improve the rates of appropriate investigations and improve overall management. A S. aureus bacteraemia care bundle was introduced at Christchurch Hospital, New Zealand in early 2014. We assessed the impact of the intervention on the management and outcome of S. aureus bacteraemia.

Methods

A cohort study of cases of S. aureus bacteraemia was conducted following standardised care bundle introduction. Prospective enrolment of post-intervention patients occurred from 1^st January 2014 to 30^th June 2015, with retrospective review of pre-intervention cases from 1^st January 2009 to 31^st December 2013.

Results

In the pre-intervention period 447 patients had at least one episode of S. aureus bacteraemia compared to 151 patients in the post-intervention period. The two groups were similar by gender, ethnicity, and age. Significant increases in Infectious Diseases consultation rate (86.6% vs 94.8%; p=0.009), echocardiography (76.3% vs 96.3%; p<0.001), urine culture (74.0% vs 91.9%; p<0.001), follow up blood cultures (44.2% vs 83.0%; p<0.001), and at least 2 weeks of parenteral therapy (83.5% vs 92.9%; p=0.014) were observed after introduction of the bundle. There were no significant differences in rates 30-day mortality (18.6% vs. 20.5%; p=0.596), but there was a reduction in episodes of relapsed infection in the post-intervention cohort (7.4% vs 1.3%; p=0.004).

Conclusion

An integrated care bundle for the management of S. aureus bacteraemia resulted in increased use of quality of care indicators and infectious diseases review and improved patient outcome.

Ten-year retrospective review of paediatric septic arthritis in a New Zealand centre

BACKGROUND

Paediatric septic arthritis, although a rare diagnosis in the developed world, remains a significant challenge in the New Zealand population. In recent years, there has been effort to characterize the nature of paediatric bone and joint infection for New Zealand due to rising incidence of osteomyelitis and staphylococcal sepsis [1, 2]. We have sought to identify trends in presentation, diagnosis and management of paediatric septic arthritis, with added focus on ethnicity and access to healthcare.

METHODS

A ten year retrospective review of all cases < 16 years with presumed septic arthritis presenting to a tertiary referral centre between 2008 and 2018 was performed.

RESULTS

A total of 103 cases met inclusion criteria. Mean age was 5.9 years (SD +/- 4.17) with a male predominance (64%). Traditional laboratory culture method isolated an organism in 66% of cases: Staphylococcus aureus was the most common pathogen identified (61%). Incidence varied greatly by ethnicity 1:16,000 for NZ European children; 1:8760 for Pacifica and 1:4300 for Māori. Mean distance travelled by patients to reach the nearest emergency department was 38.3 km, ranging from 2 to 188 km. Assessment using NZ deprivation scores showed the Māori paediatric population were likely to reside in areas of worse socioeconomic deprivation (p = 0.0005). The majority (66%) of cases were treated surgically with a low recurrence rate (2.9%). Delayed presentation was associated with worse outcomes and more likely in patients residing > 20 km away from the nearest emergency department.

CONCLUSION

The incidence of paediatric septic arthritis in New Zealand is concerningly high within Māori and Pacific populations. Future health interventions should consider environmental, socioeconomic, and microbiological trends in the burden of disease.

Predicting the occurrence of multidrug-resistant organism colonization or infection in ICU patients: development and validation of a novel multivariate prediction model

Background

Multidrug-resistant organisms (MDROs) have emerged as an important cause of poor prognoses of patients in the intensive care unit (ICU). This study aimed to establish an easy-to-use nomogram for predicting the occurrence of MDRO colonization or infection in ICU patients.

Methods

In this study, we developed a nomogram based on predictors in patients admitted to the ICU in the First Affiliated Hospital of Xiamen University from 2016 to 2018 using univariate and multivariate logistic regression analysis. We externally validated this nomogram in patients from another hospital over a similar period, and assessed its performance by calculating the area under the receiver operating characteristic (ROC) curve (AUC) and performing a decision curve analysis.

Results

331 patients in the primary cohort and 181 patients in the validation cohort were included in the statistical analysis. Independent factors derived from the primary cohort to predict MDRO colonization or infection were male sex, higher C-reactive protein (CRP) levels and higher Pitt bacteremia scores (Pitt scores), which were all assembled in the nomogram. The nomogram yielded good discrimination with an AUC of 0.77 (95% CI 0.70–0.84), and the range of threshold probabilities of decision curves was approximately 30–95%.

Conclusion

This easy-to-use nomogram is potentially useful for predicting the occurrence of MDRO colonization or infection in ICU patients.

The Pitt Bacteremia Score Predicts Mortality in Nonbacteremic Infections

BACKGROUND

Predicting mortality risk in patients is important in research settings. The Pitt bacteremia score (PBS) is commonly used as a predictor of early mortality risk in patients with bloodstream infections (BSIs). We determined whether the PBS predicts 14-day inpatient mortality in nonbacteremia carbapenem-resistant Enterobacteriaceae (CRE) infections.

METHODS

Patients were selected from the Consortium on Resistance Against Carbapenems in Klebsiella and Other Enterobacteriaceae, a prospective, multicenter, observational study. We estimated risk ratios to analyze the predictive ability of the PBS overall and each of its components individually. We analyzed each component of the PBS in the prediction of mortality, assessed the appropriate cutoff value for the dichotomized score, and compared the predictive ability of the qPitt score to that of the PBS.

RESULTS

In a cohort of 475 patients with CRE infections, a PBS ≥4 was associated with mortality in patients with nonbacteremia infections (risk ratio [RR], 21.9; 95% confidence interval [CI], 7.0, 68.8) and with BSIs (RR, 6.0; 95% CI, 2.5, 14.4). In multivariable analysis, the hypotension, mechanical ventilation, mental status, and cardiac arrest parameters of the PBS were independent risk factors for 14-day all-cause inpatient mortality. The temperature parameter as originally calculated for the PBS was not independently associated with mortality. However, a temperature <36.0°C vs ≥36°C was independently associated with mortality. A qPitt score ≥2 had similar discrimination as a PBS ≥4 in nonbacteremia infections.

CONCLUSIONS

Here, we validated that the PBS and qPitt score can be used as reliable predictors of mortality in nonbacteremia CRE infections.

Multicenter Cohort of Patients With Methicillin-Resistant Staphylococcus aureus Bacteremia Receiving Daptomycin Plus Ceftaroline Compared With Other MRSA Treatments

Background

Daptomycin and ceftaroline (DAP-CPT) have been used for persistent methicillin-resistant Staphylococcus aureus bacteremia (MRSAB), but have rarely been compared with other therapies. This study provides an exploratory analysis of patients placed on DAP-CPT vs standard of care (SOC) for MRSAB.

Methods

This is a retrospective, matched cohort study MRSAB patients at 4 hospitals in the United States. Patients receiving DAP-CPT for ≥72 hours at any point in therapy were matched 2:1 when possible, 1:1 otherwise, to SOC, first by infection source, then age and renal function. SOC was empiric treatment with vancomycin or daptomycin and any subsequent combination antibiotic(s), except for DAP-CPT.

Results

Fifty-eight patients received DAP-CPT with 113 matched SOC. Ninety-six percent of SOC received vancomycin, and 56% (63/113) escalated therapy at least once in the treatment course. Twenty-four patients received DAP-CPT within 72 hours of index culture; 2 (8.3%) died within 30 days vs 14.2% (16/113) with SOC (P > .05). Subgroup analysis identified numerically lower mortality in DAP-CPT patients with a Charlson comorbidity index ≥3, endovascular source, and receipt of DAP-CPT within 72 hours of index culture. The median MRSAB duration was 9.3 vs 4.8 days for DAP-CPT and SOC, respectively. DAP-CPT was initiated on day 6 on average; after receipt of DAP-CPT, MRSAB duration was 3.3 days.

Conclusions

DAP-CPT treatment is often delayed in MRSAB. Combination therapy may be more beneficial if initiated earlier, particularly in patients at higher risk for mortality. Blinded, randomized, prospective studies are needed to eliminate selection bias inherent in retrospective analyses when examining DAP-CPT vs SOC.

A prospective, multicenter case control study of risk factors for acquisition and mortality in Enterobacter species bacteremia

BACKGROUND

Enterobacter is among the main etiologies of hospital-acquired infections. This study aims to identify the risk factors of acquisition and attributable mortality of Enterobacter bacteremia.

METHODS

Observational, case-control study for risk factors and prospective cohort for outcomes of consecutive cases with Enterobacter bacteremia. This study was conducted in five hospitals in Spain over a three-year period. Matched controls were patients with negative blood cultures and same sex, age, and hospitalization area.

RESULTS

The study included 285 cases and 570 controls. E. cloacae was isolated in 198(68.8%) cases and E. aerogenes in 89(31.2%). Invasive procedures (hemodialysis, nasogastric tube, mechanical ventilation, surgical drainage tube) and previous antibiotics or corticosteroids were independently associated with Enterobacter bacteremia. Its attributable mortality was 7.8%(CI95%2.7-13.4%), being dissimilar according to a McCabe index: non-fatal=3.2%, ultimately fatal=12.9% and rapidly fatal=0.12%. Enterobacter bacteremia remained an independent risk factor for mortality among cases with severe sepsis or septic shock (OR 5.75 [CI95%2.57-12.87], p<0.001), with an attributable mortality of 40.3%(CI95%25.7-53.3). Empiric therapy or antibiotic resistances were not related to the outcome among patients with bacteremia.

CONCLUSIONS

Invasive procedures, previous antibiotics and corticosteroids predispose to acquire Enterobacter bacteremia. This entity increases mortality among fragile patients and those with severe infections. Antibiotic resistances did not affect the outcome.

Predictors of mortality in patients infected with carbapenem-resistant Acinetobacter baumannii: A systematic review and meta-analysis

BACKGROUND

Carbapenem-resistant Acinetobacter baumannii (CRAB) tops the list of threats to human health. Studies exploring predictors of mortality in patients with CRAB infection produced conflicting results.

METHODS

A systematic search of the PubMed, Embase, and the Cochrane Library databases was performed from inception to June 2018 to identify studies reporting mortality predictors in patients infected with CRAB. Two authors independently assessed trials for inclusion and data extraction.

RESULTS

A total of 19 observational studies were enrolled in this study. Factors associated with mortality of patients infected with CRAB were inappropriate empirical antimicrobial treatment (odds ratio [OR], 5.04; 95% confidence interval [CI], 2.56-9.94), septic shock (OR, 5.65; 95% CI, 2.35-13.57), chronic liver disease (OR, 2.36; 95% CI, 1.33-4.16), chronic renal disease (OR, 2.02; 95% CI, 1.37-2.99), hypertension (OR, 1.74; 95% CI, 1.08-2.80), neutropenia (OR, 3.31; 95% CI, 1.25-8.77), immunosuppressant use (OR, 3.15; 95% CI, 1.94-5.11), total parenteral nutrition (OR, 1.66; 95% CI, 1.08-2.56), and intubation (OR, 5.03; 95% CI, 2.33-10.87). Acute Physiology and Chronic Health Evaluation II score at admission and Pitt bacteremia score at the onset of CRAB bacteremia were higher in nonsurvivors.

CONCLUSIONS

Our study suggests that severity of baseline condition and receiving inappropriate experience antibiotic therapy are major risk factors for higher mortality in patients with CRAB infections. These findings may help clinicians to take appropriate preventive measures and decrease mortality in such patients.

Time to positivity of blood culture is a risk factor for clinical outcomes in Staphylococcus aureus bacteremia children: a retrospective study

BACKGROUND

Staphylococcus aureus (S. aureus) is a common cause of bacteremia, which leads to significant morbidity and mortality. We investigated the relationship between time to positivity (TTP) and clinical outcomes in children with S.aureus bacteremia in the China.

METHODS

A retrospective study of Staphylococcus aureus bacteremia inpatient was performed in Children's Hospital of Chongqing Medical University in China between 29 January 2014 and 29 August 2017. TTP and clinical parameters were determined and analyzed. The receiver operating characteristic (ROC) curves were plotted for optimal cut-off selection, multivariate logistic regression tests were performed to evaluate the association between TTP and clinical outcomes.

RESULTS

Overall, 84 cases were enrolled. We stated that in-hospital mortality is significantly higher in the early TTP (≤17 h) than in the late TTP (> 17 h) group (57.14% vs 7.14%, P = 0.000). Septic shock occurred in 57.14% of patients with early TTP and in 18.57% of patients with late TTP (P = 0.002). Detailed multivariate and statistical analysis revealed that early TTP, need for vasoactive agent were independent risk factors of in-hospital mortality; early TTP, need for vasoactive agent and APACHE II score ≥ 15 were independent risk factors of septic shock incidence in S. aureus bacteremia children.

CONCLUSIONS

Overall, TTP of ≤17 h appeared to correlate with the worse outcomes for S. aureus bacteremia children. These results have important implications in the assessments and management of pediatric S. aureus bacteremia in a clinical setting.

TRIAL REGISTRATION

Retrospectively registered.

Validation of MEDS score in predicting short-term mortality of adults with community-onset bacteremia

BACKGROUND

The Mortality in Emergency Department Sepsis (MEDS) score can be used to stratify ED patients with suspected infections according to mortality risk. However, it has yet to be externally validated for patients having bloodstream infections.

METHODS

We retrospectively computed clinical information for the MEDS score, Pitt bacteremia score (PBS), Charlson comorbidity index (CCI), and McCabe-Jackson comorbid classification (MJCC) for adults with community-onset bacteremia. The MEDS score was validated by the comparisons with the following scoring systems: the PBS, CCI, MJCC, PBS plus MJCC, and PBS plus CCI. We evaluated goodness-of-fit statistics and c-statistics as measures of model calibration and discrimination, respectively.

RESULTS

Of 2328 adults, a good calibration for 28-day crude mortality was obtained only in the MEDS score and PBS plus MJCC; a higher c-statistic (0.870, P < 0.001) were achieved by the MEDS score, compared to the PBS, CCI MJCC, PBS plus MJCC, and PBS plus CCI. A high c-statistic was observed in two combinative scoring system: the PBS plus CCI (0.855, P < 0.001) and PBS plus MJCC (0.843, P < 0.001). According to the Kaplan-Meier curves, 28-day crude mortality significantly differed between patients with scores equal to or higher than selected cutoff values and those with scores lower than selected cutoff values: 10 in the MEDS score and 5 in the PBS plus MJCC, respectively.

CONCLUSION

The MEDS score is an excellent predictor of short-term outcomes in patients with community-onset bacteremia because it provides estimates with higher calibration and discrimination than those of the other scoring systems.

Utility of qSOFA score in identifying patients at risk for poor outcome in Staphylococcus aureus bacteremia

Background

The prognostic capability of the quick Sequential Organ Failure Assessment (qSOFA) bedside scoring tool is uncertain in non-ICU patients with sepsis due to bacteremia given the low number of patients previously evaluated.

Methods

We performed a retrospective cohort study of adult hospitalized patients with Staphylococcus aureus bacteremia (SAB). Medical charts were reviewed to determine qSOFA score, systemic inflammatory response syndrome (SIRS) criteria, and Pitt bacteremia score (PBS) at initial presentation; their predictive values were compared for ICU admission within 48 h, ICU stay duration > 72 h, and 30-day mortality.

Results

Four hundred twenty-two patients were included; 22% had qSOFA score ≥2. Overall, mean age was 56y and 75% were male. More patients with qSOFA ≥2 had altered mentation (23% vs 5%, p < 0.0001), were infected with MRSA (42% vs 30%, p = 0.03), had endocarditis or pneumonia (29% vs 15%, p = 0.0028), and bacterial persistence ≥4d (34% vs 20%, p = 0.0039) compared to qSOFA <2 patients. Predictive performance based on AUROC was better (p < 0.0001) with qSOFA than SIRS criteria for all three outcomes, but similar to PBS ≥2. qSOFA≥2 was the strongest predictor for poor outcome by multivariable analysis and showed improved specificity but lower sensitivity than SIRS ≥2.

Conclusions

qSOFA is a simple 3-variable bedside tool for use at the time of sepsis presentation that is more specific than SIRS and simpler to calculate than PBS in identifying septic patients at high risk for poor outcomes later confirmed to have S. aureus bacteremia.

A retrospective analysis of risk factors and outcomes in patients with extended-spectrum beta-lactamase-producing Escherichia coli bloodstream infections

OBJECTIVE

Risk factors and outcomes associated with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) bloodstream infections (BSI) are not yet fully understood.

METHODS

This was a retrospective analysis of patients with E. coli BSI treated over a 4-year period. The characteristics of bacteremia caused by ESBL-producing versus non-ESBL-producing E. coli were compared. Factors influencing mortality were also assessed.

RESULTS

Of 554 eligible patients, 58.9% developed ESBL-producing E. coli. Multivariate analysis showed that urinary tract infections, stomach tube catheterization, and prior cephalosporin exposure were independent risk factors for the emergence of ESBL-producing E. coli BSI. No significant differences in 30-day mortality were seen in patients with BSI caused by ESBL-producing or non-ESBL-producing E. coli (11.1% vs. 9.2%; P=0. 642). Factors independently associated with a higher risk of mortality were previous carbapenem exposure, high APACHE II score, and respiratory tract origin.

CONCLUSIONS

This study showed that prior UTIs and previous cephalosporin exposure represent significant risk factors for the development of ESBL-producing E. coli BSI. Previous carbapenem exposure, high APACHE II score, and a respiratory tract origin were seen to be independent mortality risk factors in patients with E. coli BSI.

Intravenous to oral switch therapy in cancer patients with catheter-related bloodstream infection due to methicillin-sensitive Staphylococcus aureus: A single-center retrospective observational study

The most common complication in cancer patients is catheter-related bloodstream infection (CRBSI), of which Staphylococcus aureus is a common pathogen. Although S. aureus CRBSI patients are recommended for prolonged intravenous therapy, this is often not feasible. We assessed the effectiveness of switching from intravenous to oral antimicrobial therapy in cancer patients with CRBSI due to methicillin-sensitive S. aureus (MSSA). We conducted a retrospective observational study of 60 patients at one tertiary-care cancer center between April 2005 and March 2016. Patients who received effective intravenous (IV) antibiotics for at least 10 days (IV group) were compared to the IV group of patients who had switched to effective oral (PO) antibiotics after IV treatment for at least 10 days (IV + PO group). The primary endpoint was all-cause mortality within 90 days. Univariate and propensity score-adjusted multivariate logistic regression analyses using variables likely to influence the outcomes were performed. Of the 60 patients, 32 (53.3%) and 28 (46.7%) were in the IV and IV + PO groups, respectively. The median antibiotic treatment durations in the IV and IV + PO groups were 17 (13-31) and 33 (26-52) days, respectively (p<0.001). The 90-day mortality in the IV and IV + PO groups were 53.1% (17/32) and 10.7% (3/28), respectively (p = 0.001). Univariate logistic regression model showed that the odds ratios of oral switch therapy for 90-day mortality was 0.106 (95% confidence interval [CI]: 0.027-0.423; p = 0.001). The propensity score-adjusted multivariate logistic regression model estimated the odds ratios of oral switched therapy for 90-day mortality as 0.377 (95% CI: 0.037-3.884; p = 0.413). Our results suggest that oral switch therapy was not associated with mortality in cancer patients with CRBSI due to MSSA compared with no oral switch therapy. Oral switch therapy may be a reasonable option for patients with CRBSI due to MSSA.

Clinical Outcomes Associated With Linezolid Resistance in Leukemia Patients With Linezolid-Resistant Staphylococcus epidermidis Bacteremia

Background

Coagulase-negative staphylococci, including Staphylococcus epidermidis, are the most common cause of bloodstream infection in cancer patients. Linezolid resistance is increasingly identified in S. epidermidis, but whether such resistance alters the clinical course of S. epidermidis infections is unknown. The purpose of this study was to assess the clinical impact of linezolid resistance in leukemia patients with S. epidermidis bloodstream infection.

Methods

This was a retrospective, single-center cohort study of all adult leukemia patients with S. epidermidis bacteremia treated with empiric linezolid between 2012 and 2015. The primary end point was adverse clinical outcome on day 3, defined as a composite of persistent bacteremia, fever, intensive care unit admission, or death. Fourteen- and 30-day mortality were also assessed.

Results

Eighty-two unique leukemia patients with S. epidermidis were identified. Linezolid resistance was identified in 33/82 (40%). Patients with linezolid-resistant S. epidermidis were significantly more likely to have persistent bacteremia (41% vs 7%; adjusted relative risk [aRR], 5.15; 95% confidence interval [CI], 1.63–16.30; P = .005); however, adverse short-term clinical outcomes overall were not more common among patients with linezolid-resistant S. epidermidis (61% vs 33%; aRR, 1.46; 95% CI, 0.92–2.32; P = .108). No differences were observed in 14- or 30-day mortality.

Conclusions

Leukemia patients with linezolid-resistant S. epidermidis bacteremia who were treated with linezolid were significantly more likely to have persistent bacteremia compared with those with linezolid-sensitive isolates. Interventions to limit the clinical impact of linezolid-resistant S. epidermidis are warranted.

Human Genetic Susceptibility to Native Valve Staphylococcus aureus Endocarditis in Patients With S. aureus Bacteremia: Genome-Wide Association Study

Staphylococcus aureus infective endocarditis (SaIE) is a severe complication of S. aureus bacteremia (SAB) occurring in up to 22% of patients. Bacterial genetic factors and host conditions for SaIE have been intensely studied before; however, to date no study has focused on predisposing host genetic factors to SaIE. The present study aimed to identify genetic polymorphisms associated with SaIE by a Genome-Wide Association Study (GWAS) of 67 patients with definite native valve SaIE (cases) and 72 matched native valve patients with SAB but without IE (controls). All patients were enrolled in the VIRSTA cohort (Le Moing et al., 2015) study. Four single nucleotide polymorphisms (SNPs) located on chromosome 3 were associated with SaIE (P < 1 × 10^-5) without reaching conventional genome-wide significance. For all, the frequency of the minor allele was lower in cases than in controls, suggesting a protective effect of the minor allele against SaIE. The same association was observed using an independent Danish verification cohort of SAB with (n = 57) and without (n = 123) IE. Ex vivo analysis of aortic valve tissues revealed that SaIE associated SNPs mentioned above were associated with significantly higher mRNA expression levels of SLC7A14, a predicted cationic amino acid transporter protein. Taken together, our results suggest an IE-protective effect of SNPs on chromosome 3 during the course of SAB. The effects of protective minor alleles may be mediated by increasing expression levels of SLC7A14 in valve tissues. We conclude that occurrence of SaIE may be the combination of a well-adapted bacterial genotype to a susceptible host.

Echocardiography has low utility in cancer patients with Staphylococcus aureus bacteraemia: findings from a retrospective study

AIM

To describe the incidence of infective endocarditis (IE) detected on echocardiography in cancer patients with confirmed Staphylococcus aureus bacteraemia (SAB).

METHODS

We retrospectively identified 95 cases of SAB in cancer patients from January 2007-March 2016. Echocardiography was ordered at the discretion of the treating team, and positive findings defined according to the Modified Duke Criteria. Complicated bacteraemia was defined by prolonged bacteraemia, presence of intracardiac device/prosthetic valve, or signs of metastatic infection.

RESULTS

Major predisposing risk factors for IE (intracardiac device, prosthetic valve, valvular disease, diabetes mellitus, renal dialysis) were present in 27% of cases. Fifty-one of 95 (54%) had a central venous catheter and 17 (18%) patients had complicated bacteraemia. Echocardiography was performed in 75/95 (79%) episodes, with transthoracic echocardiography (TTE) alone in 56, transoesophageal echocardiography (TOE) alone in 4 and both in 15. Echocardiography was diagnostic for IE in 2 patients (1 TTE, 1 TOE), including one result that led to the diagnosis of IE in a clinically unsuspected case. Four further cases of IE were diagnosed on clinical findings, resulting in an overall rate of IE of 6% (6/95). Five of these cases occurred in patients with complicated bacteraemia or ≥ 1 risk factor for IE. No patient was readmitted due to IE.

CONCLUSION

IE is infrequent in cancer patients with uncomplicated SAB and no risk factors for IE. Performing echocardiography routinely in all cancer patients with SAB rarely alters diagnosis or affects antibiotic management and therefore should be reserved for patients with specific risk factors.

Comparison of the efficacy of nafcillin and glycopeptides as definitive therapy for patients with methicillin-susceptible Staphylococcus aureus bacteremia: a retrospective cohort study

Background

Studies have shown that the prognosis of the treatment of methicillin-susceptible S. aureus (MSSA) with glycopeptides is inferior compared to treatment with β-lactam. However, there are only few studies comparing treatment with antistaphylococcal penicillin alone to glycopeptide treatment. The aim of this study was to compare the efficacy of nafcillin, an antistaphylococcal penicillin, with that of glycopeptides as a definitive therapy for MSSA bacteremia.

Methods

Patients with MSSA bacteremia recruited from a tertiary referral hospital were enrolled in this retrospective cohort study. Demographic characteristics, laboratory data, and clinical outcome of the treatment were compared between a group receiving nafcillin and a group receiving glycopeptides.

Results

A total of 188 patients with MSSA bacteremia were included in this study. The glycopeptide group had a higher rate of malignancy (28.6 vs. 60.8%, p < 0.001) and proportion of healthcare-associated infections (47.3 vs. 72.2%, p < 0.001) compared to the nafcillin group. The ratio of skin and soft tissue infections (30.0 vs. 16.7%, p = 0.037) and bone and joint infections (17.8 vs. 6.3%, p = 0.022), as well as levels of C-reactive protein (139.60 vs. 107.61 mg/dL, p = 0.022) were higher in the nafcillin group. All-cause 28-day mortality was significantly high in the glycopeptide group (7.7 vs. 20.6%, p = 0.013).

Conclusion

In patients with MSSA bacteremia, all-cause 28-day mortality rate was higher in a group treated with glycopeptides than in a group treated with nafcillin. Therefore, the use of nafcillin should be considered as a definitive therapy for MSSA bacteremia.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-2978-z) contains supplementary material, which is available to authorized users.

Increased Endovascular Staphylococcus aureus Inoculum Is the Link Between Elevated Serum Interleukin 10 Concentrations and Mortality in Patients With Bacteremia

Background

Cell wall peptidoglycan stimulates interleukin 10 (IL-10) production in Staphylococcus aureus bacteremia (SaB) animal models, but clinical data are not available. This study evaluates the impact of intravascular bacterial cell numbers (ie, the level of bacteremia), in patients at the time of clinical presentation on IL-10 production and its association with S. aureus bacteremia (SaB) mortality.

Methods

Blood and isolates were collected in 133 consecutive SaB patients. Serum IL-10 was quantified by an electrochemoluminescence assay. Bacterial inoculum was measured in patient sera with elevated (n = 8) or low (n = 8) IL-10 using a magnetic bacterial capture assay. Staphylococcus aureus from these 2 groups were introduced into whole blood ex vivo to determine IL-10 production with variable inocula.

Results

IL-10 serum concentration was higher in SaB patient mortality (n = 27) vs survival (n = 106) (median, 36.0 pg/mL vs 10.4 pg/mL, respectively, P < .001). Patients with elevated IL-10 more often had endovascular SaB sources. The inoculum level of SaB was higher in patients with elevated serum IL-10 vs patients with low IL-10 (35.5 vs 0.5 median CFU/mL; P = .044). Ex vivo studies showed that 108 CFU/mL yielded greater IL-10 than did 103 CFU/mL (4.4 ± 1.8 vs 1.0 ± 0.6 pg/mL; P < .01).

Conclusions

Elevated IL-10 serum concentrations at clinical presentation of SaB were highly associated with mortality. High intravascular peptidoglycan concentration, driven by a higher level of bacteremia, is a key mediator of IL-10 anti-inflammatory response that portends poor clinical outcome. Using IL-10 as an initial biomarker, clinicians may consider more aggressive antimicrobials for rapid bacterial load reduction in high-risk SaB patients.

Staphylococcus aureus bacteraemia and endocarditis - epidemiology and outcome: a review

PURPOSE

To review the epidemiology of Staphylococcus aureus bacteraemia (SAB) and endocarditis (SAE), and discuss the short- and long-term outcome.  Materials and methods: A literature review of the epidemiology of SAB and SAE.

RESULTS

The reported incidence of SAB in Western countries is 16-41/100,000 person-years. Increasing incidence has been observed in many regions, in Iceland by 27% during 1995-2008. The increase is believed to depend on changes in population risk factors and possibly better and more frequent utilization of diagnostic procedures. S. aureus is now the leading causes of infective endocarditis (IE) in many regions of the world. It accounts for 15-40% of all IE cases, and the majority of cases in people who inject drugs (PWID). Recently, the incidence of SAE in PWID in Stockholm, Sweden, was found to be 2.5/1000 person-years, with an in-hospital mortality of 2.5% in PWID as compared to 15% in non-drug users. The 30-day mortality associated with SAB amounts to 15-25% among adults in Western countries, but is lower in children (0-9%). Mortality associated with SAE is high (generally 20-30% in-hospital mortality), and symptomatic cerebral embolizations are common (12-35%). The 1-year mortality reported after SAB and SAE is 19-62% and reflects deaths from underlying diseases and complications caused by the infection. In a subset of SAE cases, valvular heart surgery is needed (15-45%), but active intravenous drug use seems to be a reason to refrain from surgery. Despite its importance, there are insufficient data on the optimal management of SAB and SAE, especially on the required duration of antibiotic therapy.  Conclusions: The epidemiology of SAB and SAE has been changing in the past decades. They still carry a substantial morbidity and mortality. Intensified studies on treatment are warranted for improving patient outcome.

Impact of a pharmacist-driven care package on Staphylococcus aureus bacteremia management in a large community healthcare network: A propensity score-matched, quasi-experimental study

OBJECTIVES

Staphylococcus aureus bacteremia (SAB) is an important cause of morbidity and mortality. Suboptimal treatment has been associated with poor patient outcomes. Our antimicrobial stewardship program (ASP) evaluated SAB management based on predefined performance measures both prior to and after instituting a "care package" intervention led by clinical pharmacists and infectious diseases physicians. The primary outcome included a 4-point "optimal care score" (OCS) consisting of targeted antibiotic therapy within 24hours, repeating blood cultures, antibiotic duration assessment, and appropriate duration of therapy. The presence of an ID consult, SAB readmission and mortality were also assessed.

METHODS

This was a quasi-experimental, propensity score matched study of SAB management. Adult patients were retrospectively evaluated from October 2011 - October 2012, and intervention took place from November 2013 - December 2015. Intervention consisted of a clinical pharmacist contacting the primary team after identification of SAB to recommend (1) appropriate antibiotics within 24hours, (2) repeat blood cultures to document clearance, (3) assessment for metastatic infection, (4) and appropriate duration of therapy. These constituted the 4-point OCS. ID consult was also recommended. Patients were propensity score matched 1:2 based on age, diabetes, presence of hardware, methicillin-resistant S. aureus (MRSA) isolate, and stratified infectious source. Patients ≥18 with SAB were included.

RESULTS

Intervention was associated with improved adherence to each metric within the OCS, and more patients in the intervention cohort achieved a perfect OCS of 4. Intervention was associated with a lower rate of readmission and mortality.

CONCLUSION

A pharmacist-driven, ASP intervention on SAB therapy was associated with increased adherence to core SAB care metrics and reduced relapse and mortality.

Epidemiology of Methicillin-Resistant Staphylococcus aureus Bacteremia in Children

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with high rates of treatment failure in adults. The epidemiology, clinical outcomes, and risk factors for treatment failure associated with MRSA bacteremia in children are poorly understood.

METHODS

Multicenter, retrospective cohort study of children ≤18 years hospitalized with MRSA bacteremia across 3 tertiary care children's hospitals from 2007 to 2014. Treatment failure was defined as persistent bacteremia >3 days, recurrence of bacteremia within 30 days, or attributable 30-day mortality. Potential risk factors for treatment failure, including the site of infection, vancomycin trough concentration, critical illness, and need for source control, were collected via manual chart review and evaluated using multivariable logistic regression.

RESULTS

Of 232 episodes of MRSA bacteremia, 72 (31%) experienced treatment failure and 23% developed complications, whereas 5 (2%) died within 30 days. Multivariable analysis of 174 children treated with vancomycin with steady-state vancomycin concentrations obtained found that catheter-related infections (odds ratio [OR], 0.36; 95% confidence interval [CI]: 0.13-0.94) and endovascular infections (OR, 4.35; 95% CI: 1.07-17.7) were associated with lower and higher odds of treatment failure, respectively, whereas a first vancomycin serum trough concentration <10 μg/mL was not associated with treatment failure (OR, 1.34; 95% CI, 0.49-3.66). Each additional day of bacteremia was associated with a 50% (95% CI: 26%-79%) increased odds of bacteremia-related complications.

CONCLUSIONS

Hospitalized children with MRSA bacteremia frequently suffered treatment failure and complications, but mortality was low. The odds of bacteremia-related complications increased with each additional day of bacteremia, emphasizing the importance of achieving rapid sterilization.

Diabetes increases the risk of disease and death due to Staphylococcus aureus bacteremia. A matched case-control and cohort study

BACKGROUND

This study investigated the effect and influence of diabetes severity on susceptibility and 30-day mortality of Staphylococcus aureus bacteremia (SAB).

METHODS

Nationwide population-based study of individuals with SAB and matched population controls. Diabetes severity was categorized based on International Classification of Diseases codes and the odds ratio (OR) with 95% confidence intervals (CI) of SAB associated with diabetes was estimated by conditional logistic regression analysis. Hazard ratios (HR) were analyzed by Cox proportional regression. Analyses were adjusted for age, sex, comorbidity, hospital contact and diabetes duration.

RESULTS

Of 25,855 SAB cases, 2797 (10.8%) had diabetes and 2913 (11.3%) had diabetes with complications compared to 14,189 (5.5%) and 5499 (2.1%) of 258,547 controls. This corresponded to an increased risk of SAB associated with diabetes without complications (OR 1.83 (95% CI 1.74-1.92)) and of diabetes with complications (OR 3.62 (95% CI 3.43-3.81) compared to no diabetes. The risk of SAB was highest within the first year of diabetes. Diabetes without complications was associated with an increased risk of 30-day mortality (HR 1.62 (95% CI 1.01-2.60)) compared to no diabetes. Diabetes with complications was overall not associated with increased 30-d mortality (HR 1.36 (95% CI 0.84-2.20)) except for individuals with ketoacidosis/coma (HR 2.01 (95% 1.17-3.45)).

CONCLUSIONS

Diabetes, particularly, diabetes with complications significantly increased the risk of SAB. In contrast, there was an increased risk of 30-day mortality after SAB for diabetes without complications but not for diabetes with complications overall. Diabetes with ketoacidosis/coma conferred the highest relative risk of 30-day mortality.

Staphylococcus aureus bacteremia in immunosuppressed patients: a multicenter, retrospective cohort study

Staphylococcus aureus bacteremia (SAB) causes significant morbidity and mortality. We assessed the disease severity and clinical outcomes of SAB in patients with pre-existing immunosuppression, compared with immunocompetent patients. A retrospective cohort investigation studied consecutive patients with SAB hospitalized across six hospitals in Toronto, Canada from 2007 to 2010. Patients were divided into immunosuppressed (IS) and immunocompetent (IC) cohorts; the IS cohort was subdivided into presence of one and two or more immunosuppressive conditions. Clinical parameters were compared between cohorts and between IS subgroups. A competing risk model compared in-hospital mortality and time to discharge. A total of 907 patients were included, 716 (79%) were IC and 191 (21%) were IS. Within the IS cohort, 111 (58%) had one immunosuppressive condition and 80 (42%) had two or more conditions. The overall in-hospital mortality was 29%, with no differences between groups (IS 32%, IC 28%, p = 0.4211). There were no differences in in-hospital mortality (sub-distribution hazard ratio [sHR] 1.17, 95% confidence interval [CI] 0.88-1.56, p = 0.2827) or time to discharge (sHR 0.94, 95% CI 0.78-1.15, p = 0.5570). Independent mortality predictors for both cohorts included hypotension at 72 h (IS: p < 0.0001, IC: p < 0.0001) and early embolic stroke (IS: p < 0.0001, IC: p = 0.0272). Congestive heart failure was a mortality predictor in the IS cohort (p = 0.0089). Fever within 24 h (p = 0.0092) and early skin and soft tissue infections (p < 0.0001) were survival predictors in the IS cohort. SAB causes significant mortality regardless of pre-existing immune status, but immunosuppressed patients do not have an elevated risk of mortality relative to immunocompetent patients.

Factors associated with 12 week case-fatality in Staphylococcus aureus bacteraemia: a prospective cohort study

Staphylococcus aureus bacteraemia (SAB) is a frequent and deadly disease. Given the lack of a randomized trial, optimal first-line antibiotic treatment is still debated. Our aim was to identify prognostic factors in SAB patients and to analyse the impact of first-line antibiotics. The VIRSTA prospective cohort study was conducted in eight tertiary care centres in France. Consecutive incident adults in whom a blood culture drawn in participating centres grew S. aureus between April 2009 and October 2011 were prospectively followed for 12 weeks. Factors associated with 12-week case-fatality were identified by multivariate logistic regression. We enrolled 2091 patients and analysed survival in 1972 (median age 67.8 years, interquartile range 55.5-78.9; females 692/1972, 35.1%). SAB was nosocomial or healthcare-related in 1372/1972 (69.6%) of cases and the primary focus was unknown in 414/1972 (21.0%) of cases. Week 12 case-fatality rate was 671/1972 (34.0%). The main independent prognostic factors on multivariate analysis were age (adjusted OR by 10-year increment 1.56; 95% CI 1.44-1.69), septic shock (OR 5.11; 95% CI 3.84-6.80), metastatic cancer (OR 4.28; 95% CI 2.88-6.38), and unknown primary focus (OR 2.62; 95% CI 2.02-3.41). In the 1538 patients with methicillin-sensitive S. aureus (MSSA) bacteraemia, first-line empiric antistaphylococcal penicillins (OR 0.40; 95% CI 0.17-0.95) and vancomycin (OR 0.37; 95% CI 0.17-0.83), alone or combined with an aminoglycoside, were associated with better outcome compared with other antibiotics. There are few modifiable prognostic factors for SAB. Initiating empiric antibiotics with antistaphylococcal penicillins or vancomycin may be associated with better outcome in MSSA bacteraemia.

Long-term mortality and causes of death associated with Staphylococcus aureus bacteremia. A matched cohort study

OBJECTIVES

Data describing long-term mortality in patients with Staphylococcus aureus bacteremia (SAB) is scarce. This study investigated risk factors, causes of death and temporal trends in long-term mortality associated with SAB.

METHODS

Nationwide population-based matched cohort study. Mortality rates and ratios for 25,855 cases and 258,547 controls were analyzed by Poisson regression. Hazard ratio of death was computed by Cox proportional hazards regression analysis.

RESULTS

The majority of deaths occurred within the first year of SAB (44.6%) and a further 15% occurred within the following 2-5 years. The mortality rate was 14-fold higher in the first year after SAB and 4.5-fold higher overall for cases compared to controls. Increasing age, comorbidity and hospital contact within 90 days of SAB was associated with an increased risk of death. The overall relative risk of death decreased gradually by 38% from 1992-1995 to 2012-2014. Compared to controls, SAB patients were more likely to die from congenital malformation, musculoskeletal/skin disease, digestive system disease, genitourinary disease, infectious disease, endocrine disease, injury and cancer and less likely to die from respiratory disease, nervous system disease, unknown causes, psychiatric disorders, cardiovascular disease and senility. Over time, rates of death decreased or were stable for all disease categories except for musculoskeletal and skin disease where a trend towards an increase was seen.

CONCLUSION

Long-term mortality after SAB was high but decreased over time. SAB cases were more likely to die of eight specific causes of death and less likely to die of five other causes of death compared to controls. Causes of death decreased for most disease categories. Risk factors associated with long-term mortality were similar to those found for short-term mortality. To improve long-term survival after SAB, patients should be screened for comorbidity associated with SAB.