Predictors of one-year all-cause mortality and infection-related mortality in patients with Staphylococcus aureus bacteraemia

Community-Acquired Staphylococcus aureus Bacteremia Among People Who Inject Drugs: A National Cohort Study in England, 2017-2020

BACKGROUND

People who inject drugs (PWID) are at increased risk of community-acquired Staphylococcus aureus bacteremia (CA-SAB), but little is known about clinical outcomes of CA-SAB in PWID compared with the wider population of patients with CA-SAB.

METHODS

Three national datasets were linked to provide clinical and mortality data on patients hospitalized with CA-SAB in England between 1 January 2017 and 31 December 2020. PWID were identified using the International Classification of Diseases, Tenth Revision code for "mental health and behavioral disorder due to opioid use" (F11). Multivariable logistic regression was used to estimate adjusted odds ratios (aORs) for associations of PWID with 30-day all-cause mortality and 90-day hospital readmission.

RESULTS

In 10 045 cases of CA-SAB, 1612 (16.0%) were PWID. Overall, 796 (7.9%) patients died within 30 days of CA-SAB admission and 1189 (11.8%) patients were readmitted to hospital within 90 days of CA-SAB. In those without infective endocarditis, there was strong evidence of lower odds of mortality among PWID compared with non-PWID (aOR, 0.47 [95% confidence interval {CI}: .33-.68]; P < .001), whereas there was no association in CA-SAB case fatality with endocarditis (aOR, 1.40 [95% CI: .87-2.25]; P = .163). PWID were less likely to be readmitted within 90 days of CA-SAB (aOR, 0.79 [95% CI: .65-.95]; P = .011).

CONCLUSIONS

In this large cohort study of patients with CA-SAB in England, PWID had lower odds of death in the absence of endocarditis and lower odds of readmission within 90 days compared to non-PWID patients. This study highlights the overrepresentation of PWID among patients with CA-SAB nationally.

Longer-term Mortality and Kidney Outcomes of Participants in the Combination Antibiotics for Methicillin-Resistant Staphylococcus aureus (CAMERA2) Trial: A Post Hoc Analysis

Background

The Combination Antibiotic Therapy for Methicillin-Resistant Staphylococcus aureus (CAMERA2) trial ceased recruitment in July 2018, noting that a higher proportion of patients in the intervention arm (combination therapy) developed acute kidney injury (AKI) compared to the standard therapy (monotherapy) arm. We analyzed the long-term outcomes of participants in CAMERA2 to understand the impact of combination antibiotic therapy and AKI.

Methods

Trial sites obtained additional follow-up data. The primary outcome was all-cause mortality, censored at death or the date of last known follow-up. Secondary outcomes included kidney failure or a reduction in kidney function (a 40% reduction in estimated glomerular filtration rate to <60 mL/minute/1.73 m²). To determine independent predictors of mortality in this cohort, adjusted hazard ratios were calculated using a Cox proportional hazards regression model.

Results

This post hoc analysis included extended follow-up data for 260 patients. Overall, 123 of 260 (47%) of participants died, with a median population survival estimate of 3.4 years (235 deaths per 1000 person-years). Fifty-five patients died within 90 days after CAMERA2 trial randomization; another 68 deaths occurred after day 90. Using univariable Cox proportional hazards regression, mortality was not associated with either the assigned treatment arm in CAMERA2 (hazard ratio [HR], 0.84 [95% confidence interval [CI], .59-1.19]; P = .33) or experiencing an AKI (HR at 1 year, 1.04 [95% CI, .64-1.68]; P = .88).

Conclusions

In this cohort of patients hospitalized with methicillin-resistant S aureus bacteremia, we found no association between either treatment arm of the CAMERA2 trial or AKI (using CAMERA2 trial definition) and longer-term mortality.

A scoring system for the preoperative evaluation of prognosis in spinal infection: the MSI-20 score

BACKGROUND CONTEXT

Spinal infection (SI) is a life-threatening condition and its treatment remains challenging. Recent studies have supported early and aggressive surgery, but mortality still reaches 5% to 10% and it remains unclear, if an aggressive surgical strategy also applies for severely sick patients.

PURPOSE

The aim of this analysis was to generate an assessment score to predict mortality of SI in order to facilitate decision-making.

STUDY DESIGN

Retrospective risk factor analysis.

PATIENT SAMPLE

Two hundred fifty-two patients were retrospectively analyzed.

OUTCOME MEASURES

Physiologic measures, functional measures.

METHODS

Diagnosis was based on clinical presentation, imaging findings and inflammatory markers. Factors associated with mortality were identified by multivariate analysis, weighted according to their relative risk ratio (RR) and included in the novel assessment score.

RESULTS

Eight parameters were included: (1) BMI, (2) ASA score, (3) presence of sepsis, (4) age-adjusted Charlson Comorbidity Index, (5) presence and degree of renal failure, (6) presence of hepatopathy, (7) neurological deficits and (8) CRP levels at diagnosis. Each parameter was assigned a certain range of points, resulting in a maximum total score of 20. The mortality in spinal infection (MSI-20) score - indicating poorer status with higher values - was obtained for each patient and correlated with mortality.

CONCLUSION

An MSI-20 score of 11 or more points seems to identify the small group of patients being "too sick to undergo surgery," while early surgery can be recommended in the remainder (MSI-20 ≤10). Our results need to be confirmed in prospective studies, but may give guidance for indicating surgery even in rather sick and comorbid patients.

What Is the Optimal Follow-up Length for Mortality in Staphylococcus aureus Bacteremia? Observations From a Systematic Review of Attributable Mortality

Background

Deaths following Staphylococcus aureus bacteremia (SAB) may be related or unrelated to the infection. In SAB therapeutics research, the length of follow-up should be optimized to capture most attributable deaths and minimize nonattributable deaths. We performed a secondary analysis of a systematic review to describe attributable mortality in SAB over time.

Methods

We systematically searched Medline, Embase, and Cochrane Database of Systematic Reviews from 1 January 1991 to 7 May 2021 for human observational studies of SAB. To be included in this secondary analysis, the study must have reported attributable mortality. Two reviewers extracted study data and assessed risk of bias independently. Pooling of study estimates was not performed due to heterogeneity in the definition of attributable deaths.

Results

Twenty-four observational cohort studies were included. The median proportion of all-cause deaths that were attributable to SAB was 77% (interquartile range [IQR], 72%–89%) at 1 month and 62% (IQR, 58%–75%) at 3 months. At 1 year, this proportion was 57% in 1 study. In 2 studies that described the rate of increase in mortality over time, 2-week follow-up captured 68 of 79 (86%) and 48 of 57 (84%) attributable deaths that occurred by 3 months. By comparison, 1-month follow-up captured 54 of 57 (95%) and 56 of 60 (93%) attributable deaths that occurred by 3 months in 2 studies.

Conclusions

The proportion of deaths that are attributable to SAB decreases as follow-up lengthens. Follow-up duration between 1 and 3 months seems optimal if evaluating processes of care that impact SAB mortality.

Clinical Trials Registration

PROSPERO CRD42021253891.

Impact of the Acceptance of the Recommendations Made by a Meropenem Stewardship Program in a University Hospital: A Pilot Study

Antimicrobial stewardship programs (ASP) promote appropriate antimicrobial use. We present a 4-year retrospective study that evaluated the clinical impact of the acceptance of the recommendations made by a meropenem-focused ASP. A total of 318 meropenem audits were performed. The ASP team (comprising infectious disease physicians, pharmacists and microbiologists) considered meropenem use in 96 audits (30.2%) to be inappropriate. The reasons to consider these uses inappropriate were the possibility of de-escalating to a narrower-spectrum antibiotic, in 66 (68.7%) audits, and unnecessary meropenem use, in 30 (31.3%) audits. The ASP team recommended de-escalation in 66 audits (68.7%) and discontinuation of meropenem in 30 audits (31.3%). ASP interventions were stratified according to whether or not recommendations were followed. The group in which recommendations were accepted and followed (i.e., accepted audit, AA) included 66 audits (68.7%) and the group in which recommendations were not followed (i.e., rejected audit, RA) included 30 (31.3%) audits. The comorbidity of the AA group (Charlson score) was higher than in the RA group (7.0 (5.0–9.0) vs. 6.0 (4.0–7.0), p = 0.02). Discontinuation of meropenem was recommended in 83.3% of audits in the AA group vs. 62.2% in the RA group (OR 3.05 (1.03–8.99), p = 0.04). Ertapenem de-escalation resulted in a 100% greater rate of follow-up compared with the non-carbapenem option (100% vs. 51.9%, OR 1.50 (1.21–1.860), p = 0.001). Significant differences were observed in the AA group when cultures were taken before antibiotic prescription—98.5% vs. 83.3% (p = 0.01, OR 13.0 (1.45–116.86))—or when screening cultures were taken—45.5% vs. 19.2% (p = 0.03, OR 3.5 (1.06–11.52)). There were no differences between the groups in terms of overall mortality and 30-day mortality, length of stay, Clostridiodes difficile infection, 30-day readmission or hospitalization costs. In conclusion, meropenem ASP recommendations contributed to a decrease in meropenem prescription without worsening clinical and economic outcomes.

Impact of agr Functionality on the Outcome of Patients with Methicillin-Susceptible Staphylococcus aureus Bacteremia

Dysfunctional accessory gene regulator (agr) is associated with unfavorable outcomes in invasive methicillin-resistant Staphylococcus aureus infections. However, it is unknown whether this association persists in methicillin-susceptible Staphylococcus aureus bacteremia (MSSA-B). This study evaluated the association between agr dysfunction and mortality in patients with MSSA-B. This retrospective cohort study included MSSA-B patients (≥15 years) enrolled from June 2014 to June 2019 and retrospectively collected their demographic and clinical information. Stored causative strains were measured for agr functionality by δ-hemolysin production assays. Among 244 MSSA-B patients, 91 (37.3%) and 153 (62.7%) had dysfunctional and functional agr MSSA-B, respectively. Ninety-day mortality occurred in 18.7% and 17.6% dysfunctional and functional groups, respectively (P = 0.97). Kaplan-Meier analysis showed that mortality due to dysfunctional agr MSSA-B was not significantly higher (P = 0.82). Age, sites, the severity of infection, and comorbidity adjusted hazard ratio (aHR) of the dysfunctional group for 90-day mortality was 1.303 (95% confidence interval [CI], 0.698 to 2.436, P = 0.41). Mortality due to MSSA-B with sequential organ failure assessment (SOFA) scores of 2 to 5 was significantly higher in the dysfunctional group (P = 0.03), and the dysfunctional agr aHR for 90-day mortality was 3.260 (95% CI, 1.050 to 10.118, P = 0.04). The agr dysfunction of causative organisms can have a significant effect on the outcomes of MSSA-B in patients with moderate severity (SOFA scores 2 to 5).

IMPORTANCE Few studies have examined the association between methicillin-susceptible Staphylococcus aureus (MSSA) infection and accessory gene regulator (agr) functionality. We evaluated the association between agr dysfunction and mortality in patients with MSSA bacteremia. Dysfunctional agr is associated with lower survival in MSSA bacteremia patients with moderately severe sequential organ failure assessment (SOFA) scores of 2 to 5. We found that the agr functionality of causative organisms may have an effect on patients’ outcomes in MSSA like in methicillin-resistant S. aureus.

Development of a core outcome set for clinical trials aimed at improving antimicrobial stewardship in care homes

Background

Diverse outcomes reported in clinical trials of antimicrobial stewardship (AMS) interventions in care homes have hindered evidence synthesis. Our main objective was to develop a core outcome set (COS) for use in trials aimed at improving AMS in care homes.

Methods

A refined inventory of outcomes for AMS interventions in care homes, compiled from a previous study, was rated in a three-round international Delphi survey with 82 participants, using a nine-point Likert scale (from 1, unimportant, to 9, critical). This was followed by an online consensus exercise with 12 participants from Northern Ireland to finalise the COS content. Subsequently, a suitable outcome measurement instrument (OMI) was selected for each outcome in the COS by: identifying existing OMIs through a literature search and experts’ suggestions, assessing the quality of OMIs, and selecting one OMI for each core outcome via a two-round international Delphi survey with 59 participants.

Results

Of 14 outcomes initially presented, consensus was reached for inclusion of five outcomes in the COS after the three-round Delphi survey and the online consensus exercise, comprising the total number of antimicrobial courses prescribed, appropriateness of antimicrobial prescribing, days of therapy per 1000 resident-days, rate of antimicrobial resistance, and mortality related to infection. Of 17 potential OMIs identified, three were selected for the two-round Delphi exercise after the quality assessment. Consensus was reached for selection of two OMIs for the COS.

Conclusion

This COS is recommended to be used in clinical trials aimed at improving AMS in care homes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-021-00925-8.

Novel Multiparametric Nomogram for Overall Survival Prediction in Complicated Intra-Abdominal Infection: A Multicenter Study in China

Background: Complicated intra-abdominal infections (cIAIs) in the abdominal cavity or within an abdominal organ are numerous and frequent dangerous entities in the treatment of critically ill patients. Early clinical evaluation is necessary.

Methods: This retrospective multicenter study included patients from 10 intensive care units (ICUs). Risk factors for the overall survival (OS) of patients with cIAI were selected using least absolute shrinkage and selection operator regression, and a nomogram was constructed subsequently. Calibration curve and receiver operating characteristic (ROC) curve were used to evaluate the calibration and discriminative ability.

Results: In total, 544 patients diagnosed with cIAI were enrolled and divided into the study (n = 276) and validation (n = 268) sets. Sex, acute gastrointestinal injury, acute kidney injury, rare bacterium infection, Charlson score, and APACHE II score were identified as independent risk factors and were constructed for the nomogram. The nomogram showed marked calibration capability with a concordance index (C-index) of 0.909 and 0.831 in the study and validation set, respectively. Compared with the common clinical prognostic scoring system, the nomogram achieved the highest discrimination ability with an area under the curve (AUC) value of 0.91 and 0.83 in the study set and validation set, respectively.

Conclusions: Our newly constructed nomogram provides a useful tool for risk stratification and prognosis evaluation of cIAI.

Early surgery may lower mortality in patients suffering from severe spinal infection

PURPOSE

Spinal infection (SI) is a life-threatening condition and treatment remains challenging. Numerous factors influence the outcome of SI and both conservative and operative care can be applied. As SI is associated with mortality rates between 2 and 20% even in developed countries, the purpose of the present study was to investigate the occurrence and causes of death in patients suffering from SI.

METHODS

A retrospective analysis was performed on 197 patients, categorized into two groups according to their outcome: D (death) and S (survival). The diagnosis was based on clinical and imaging (MRI) findings. Data collected included demographics, clinical characteristics, comorbidities, infection parameters, treatment details, outcomes, and causes of death.

RESULTS

The number of deaths was significantly higher in the conservative group (n = 9/51, 18%) compared with the operative counterpart (n = 8/146, 6%; p = 0.017). Death caused by septic multiorgan failure was the major cause of fatalities (n = 10/17, 59%) followed by death due to cardiopulmonary reasons (n = 4/17, 24%). The most frequent indication for conservative treatment in patients of group D included "highest perioperative risk" (n = 5/17, 29%).

CONCLUSION

We could demonstrate a significantly higher mortality rate in patients solely receiving conservative treatment. Mortality is associated with number and type of comorbidities, but also tends to be correlated with primarily acquired infection. As causes of death are predominantly associated with a septic patient state or progression of disease, our data may call for an earlier and more aggressive treatment. Nevertheless, prospective clinical trials will be mandatory to better understand the pathogenesis and course of spinal infection, and to develop high quality, evidence-based treatment recommendations.

Does extraction of cardiac implantable electronic devices improve outcome in patients with Staphylococcus aureus bacteraemia?

BACKGROUND

Staphylococcus aureus bacteraemia (SAB) is recognized as an infection that is difficult to treat and with high risk of device related infection. Extraction/explantation of cardiac implantable electronic devices (CIED) is recommended in SAB patients but studies evaluating long-term prognosis are scarce.

MATERIALS AND METHODS

In this retrospective cohort study, 626 consecutive SAB patients were identified in routine diagnostics (November 2014-October 2016). Patient characteristic, infective endocarditis (IE) incidence and mortality were compared for patients with and without CIED.

RESULTS

SAB patients with CIED (n = 33) compared to non-CIED patients (n = 593) were older (83 versus 70 years, p = .0001), had a higher 30-day mortality (12/33, 36% versus 119/593, 20%, p = .044) and higher incidence of IE (9/33, 27% versus 41/593, 7%, p = .0006). One-year mortality was 19/33 (58%) among the SAB CIED patients. Echocardiography was performed in all nine patients with CIED-IE but only in 14/24 (58%) of the 24 SAB CIED patients that were considered not having IE. However, if patients with very early mortality were excluded, echocardiography was performed in 14/17 (82%) of SAB CIED-non-IE patients. CIED extraction/explantation during intravenous antibiotic treatment was only performed in three patients with SAB CIED-IE and in one non-IE patient. One year post treatment initiation, 14 out of 33 SAB CIED patients were alive of whom only one had CIED extraction/explantation performed as part of treatment.

CONCLUSION

Staphylococcus aureus bacteraemia in CIED patients is associated with poor prognosis but in a subgroup of patients survival beyond one year was seen despite retainment of the electronic device.

Formal Infectious Diseases Specialist Consultation Improves Long-term Outcome of Methicillin-Sensitive Staphylococcus aureus Bacteremia

Background

Formal infectious diseases specialist (IDS) consultation has been shown to improve short-term outcomes in Staphylococcus aureus bacteremia (SAB), but its effect on long-term outcomes lacks evaluation.

Methods

This retrospective study followed 367 methicillin-sensitive (MS) SAB patients for 10 years. The impact of formal IDS consultation on risk for new bacteremia and outcome during long-term follow-up was evaluated. Patients who died within 90 days were excluded to avoid interference from early deceased patients.

Results

Three hundred four (83%) patients had formal IDS consultation, whereas 63 (17%) received informal or no IDS consultation. Formal consultation, compared with informal or lack of consultation, was associated with a reduced risk of new bacteremia caused by any pathogen within 1 year (odds ratio [OR], 0.39; 95% confidence interval [CI], 0.18–0.84; P = .014; 8% vs 17%) and within 3 years (OR, 0.39; 95% CI, 0.19–0.80; P = .010; 9% vs 21%), whereas a trend toward lower risk was observed within 10 years (OR, 0.56; 95% CI, 0.29–1.08; P = .079; 16% vs 25%). Formal consultation, compared with informal or lack of consultation, improved outcomes at 1 year (OR, 0.16; 95% CI, 0.06–0.44; P < .001; 3% vs 14%), at 3 years (OR, 0.19; 95% CI, 0.09–0.42; P < .001; 5% vs 22%), and at 10 years (OR, 0.43; 95% CI, 0.24–0.74; P = .002; 27% vs 46%). Considering all prognostic parameters, formal consultation improved outcomes (HR, 0.42; 95% CI, 0.27–0.65; P < .001) and lowered risk for any new bacteremia (OR, 0.45; 95% CI, 0.23–0.88; P = .02) during 10 years of follow-up.

Conclusions

MS-SAB management by formal IDS consultation, compared with informal or lack of IDS consultation, reduces risk for new bacteremia episodes and improves long-term prognosis up to 10 years.