Bloodstream infections in the elderly: what is the real goal?

Clinical features and risk factors of older adults with bloodstream infection

OBJECTIVE

To investigate the clinical features and risk factors of bloodstream infections in the older adults.

METHODS

This was a prospective cohort multicenter study. According to the inclusion and exclusion criteria, older adults with suspected bloodstream infections from December 2020 to June 2023 were included in the analysis of the clinical features of older adults bloodstream infections.

RESULTS

A total of 338 older adultswith suspected bloodstream infections were included, of which 141 were diagnosed with bloodstream infections. The proportion of gram-negative bacteria (47.5%) was close to that of gram-positive bacteria (46.1%), while the proportion of gram-negative bacteria was slightly higher.The common clinical manifestations of bloodstream infection were fever (75.2%), decreased level of consciousness (24.8%), chills (14.2%), shock (12.1%), etc.Multivariate regression analysis showed high procalcitonin levels at admission (OR = 2.008, 95%CI 1.258-3.206, P = 0.003) and heart rate > 90 beats/min (OR = 2.104, 95%CI 1.302-3.400). P = 0.002), arterial partial blood pressure of carbon dioxide < 32 mmHg (OR = 1.922, 95%CI 1.025-3.601, P = 0.042), and coronary heart disease (OR = 1.909, 95%CI 1.134-3.213), P = 0.015) were independent risk factors for bloodstream infection in the older adults.

CONCLUSION

The proportion of gram-negative and gram-positive bacteria in bloodstream infections in older adults was similar. The common clinical features of bloodstream infection in the older adults are fever and a decreased level of consciousness, and there was no significant difference in systemic clinical manifestations between bloodstream infection and non-bloodstream infection. High procalcitonin (PCT) level, heart rate > 90 beats/min, arterial partial pressure of carbon dioxide (PaCO2) < 32 mmHg, and underlying coronary heart disease were independent risk factors for bloodstream infection in older adults.

Research and predictive analysis of the disease burden of bloodstream infectious diseases in China

BACKGROUND

Bloodstream Infection(BSI) are one of the leading causes of infection-related mortality worldwide. However, epidemiological data related to BSI in China remain very limited.

METHODS

Based on the Global Burden of Disease(GBD) database, a systematic analysis was conducted on the epidemic trends, pathogen spectrum, and the current status of Antimicrobial Resistance(AMR) related to BSI in China for the year 2021. Additionally, an Autoregressive Integrated Moving Average(ARIMA) time series model was constructed to predict the trend of the disease burden associated with BSI in China from 2022 to 2035.

RESULTS

In terms of pathogens, the top five pathogens causing deaths due to BSI in China are as follows: Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. There are significant differences in the pathogens causing BSI across different age groups. The disease burden is heaviest in the elderly population aged 70 and above. Among children under five years old, Staphylococcus aureus, Streptococcus pneumoniae, and Candida species are predominant. From 1990 to 2021, although there has been a gradual decline in mortality rates due to BSI across different age groups (with an approximately 52.4% reduction in age-standardized rates), the disease burden of BSI increases with age. This is especially evident in the population aged 70 and above, where the burden of disease is significantly higher than in other age groups. For instance, in 2021, the mortality rate for individuals aged 70-74 was 149.29 (per 100 K), while for those aged 95 and older, the mortality rate reached as high as 896.71 (per 100 K). On a global scale, the disease burden caused by BSI in China is at a moderate level. According to time series model projections, the mortality burden of BSI in China shows a complex trend toward 2035: the crude mortality rate across all age groups is expected to increase by approximately 14.26%, whereas the age-standardized mortality rate and Disability-Adjusted Life Years(DALYs) are projected to decrease significantly. Notably, the mortality burden is expected to decline most prominently in the 70 + and under 5 age groups, while the 25-44 age group is projected to see minimal change. Conversely, the mortality rates for the 5-49 age group are anticipated to increase slightly.

CONCLUSION

Staphylococcus aureus and Escherichia coli are key pathogens contributing to the high mortality burden of BSI. Additionally, the heavy burden associated with AMR poses significant challenges to clinical treatment. From 1990 to 2021, the age-standardized mortality rate mortality of BSI patients is gradually decreasing, and the change in BSI mortality will be mainly affected by the changes in population size and age structure. The forecast analysis for 2022-2035 finds that the death burden of the elderly will be the heaviest, and the mortality of people aged 5-49 years will increase slightly. BSI and its related health problems are still major challenges and need continuous attention.

CLINICAL TRIAL

Inapplicability.

Antimicrobial susceptibility of gram-negative strains isolated from bloodstream infections in China: Results from the study for monitoring antimicrobial resistance trends (SMART) 2018-2020

The study aims were to present in vitro susceptibilities of clinical isolates from Gram-negative bacteria bloodstream infections (GNBSI) collected in China. GNBSI isolates were collected from 18 tertiary hospitals in 7 regions of China from 2018 to 2020. Minimum inhibitory concentrations were assessed using a Trek Diagnostic System. Susceptibility was determined using CLSI broth microdilution, and breakpoints were interpreted using CLSI M100 (2021). A total of 1,815 GNBSI strains were collected, with E. coli (42.4%) and Klebsiella pneumoniae (28.6%) being the most prevalent species, followed by P. aeruginosa (6.7%). Susceptibility analyses revealed low susceptibilities (<40%) of ESBL-producing E. coli and K. pneumonia to third-/fourth-generation cephalosporins, monobactamases, and fluoroquinolones. High susceptibilities to colistin (95.0%) and amikacin (81.3%) were found for K. pneumoniae, while Acinetobacter baumannii exhibited a high susceptibility (99.2%) to colistin but a low susceptibility to other antimicrobials (<27.5%). Isolates from ICUs displayed lower drug susceptibility rates of K. pneumoniae and A. baumannii than isolates from non-ICUs (all P < 0.05). Carbapenem-resistant and ESBL-producing K. pneumoniae detection was different across regions (both P < 0.05). E. coli and K. pneumoniae were major contributors to GNBSI, while A. baumannii exhibited severe drug resistance in isolates obtained from ICU departments.

Innovations in Imaging: 18F-Fluorodeoxyglucose PET/CT for Assessment of Cardiovascular Infection and Inflammation

PURPOSE OF REVIEW

18F-Fluorodeoxyglucose positron emission tomography (PET) combined with computed tomography (CT), referred to as 18F-FDG PET/CT, plays a significant role in the diagnosis and management of patients with systemic infectious and inflammatory conditions. This review provides an overview of 18F-FDG PET/CT in systemic infectious and inflammatory conditions, including infective endocarditis (IE), cardiac implantable electrical device (CIED)/left ventricular assist device (LVAD) infection, sarcoidosis, and large-vessel vasculitis (LVV).

RECENT FINDINGS

This review highlights the past and present literature in the increasing role of 18F-FDG PET/CT in cardiovascular inflammation and infection, including diagnostic and prognostic findings. They key aspects of this paper are to highlight the importance of 18F-FDG PET/CT in cardiovascular infection and inflammation, and to provide illustrations of how it can contribute to patient diagnosis and management.

Clinical characteristics and bloodstream infection pathogens by gram-negative bacteria in different aged adults: A retrospective study

This study aims to determine the characteristics and distribution of pathogenic bacteria in bloodstream infections (BSIs) by gram-negative bacteria in adults. One hundred seventy-one adult patients with BSIs who were treated at the Affiliated Hospital of Chengde Medical College between January 2018 and January 2020 were included in this study. The patients were assigned to the young- and middle-aged group and elderly group based on age. General patient data were analyzed. More elderly patients had BSIs and gram-negative bacteria than young- and middle-aged patients. The incidence of underlying diseases in elderly patients was significantly higher than the young- and middle-aged patients (P < .01). The composition of Brucella spp. was significantly different between the elderly group and young- and middle-aged group (P < .05). There were significantly more gallbladder infections in the elderly group than the young- and middle-aged group, and significantly fewer elderly patients had no definite infection sites than the young- and middle-aged group (P < .05). The incidence of complications and in-hospital mortality in the elderly group was higher than the young- and middle-aged group (P < .05). BSIs caused by gram-negative bacteria mainly involved elderly patients. BSIs were characterized by complications and a poor prognosis, as well as pathogenic bacteria and primary infection sites.

Diagnostic and therapeutic yield of imaging studies in Polymicrobial and Monomicrobial Gram-negative bloodstream infections - a retrospective cohort study

PURPOSE

Appropriate antimicrobial therapy and surgical drainage, improve survival in patients with Gram negative bloodstream infections (BSI). Data about the yield of imaging studies in polymicrobial BSI is sparse. The aim of the study was to assess the need for imaging studies and surgical drainage among patients with polymicrobial compared to monomicrobial BSI.

RESULTS

In a retrospective cohort study of adult patients with Gram negative BSI, 135 patients with monomicrobial BSI were compared to 82 with polymicrobial BSI. Imaging studies were performed in 56.3 % of patients with monomicrobial BSI and in 50 % of polymicrobial BSI (p=0.4), surgical drainage was performed in 20.1 % of patients with monomicrobial BSI and 27.2 % of polymicrobial BSI (p=0.25). Surgical drainage was performed in 26.2 % of patients who survived vs. 11.8 % of patients who died (p=0.035).

CONCLUSIONS

There is no difference in the diagnostic approach to monomicrobial and polymicrobial Gram-negative BSI. Surgical drainage is associated with decreased mortality.

Clinical presentation and antimicrobial resistance of invasive Escherichia coli disease in hospitalized older adults: a prospective multinational observational study

BACKGROUND

Clinical data characterizing invasive Escherichia coli disease (IED) are limited. We assessed the clinical presentation of IED and antimicrobial resistance (AMR) patterns of causative E. coli isolates in older adults.

METHODS

EXPECT-2 (NCT04117113) was a prospective, observational, multinational, hospital-based study conducted in patients with IED aged ≥ 60 years. IED was determined by the microbiological confirmation of E. coli from blood; or by the microbiological confirmation of E. coli from urine or an otherwise sterile body site in the presence of requisite criteria of systemic inflammatory response syndrome (SIRS), Sequential Organ Failure Assessment (SOFA), or quick SOFA (qSOFA). The primary outcomes were the clinical presentation of IED and AMR rates of E. coli isolates to clinically relevant antibiotics. Complications and in-hospital mortality were assessed through 28 days following IED diagnosis.

RESULTS

Of 240 enrolled patients, 80.4% had bacteremic and 19.6% had non-bacteremic IED. One-half of infections (50.4%) were community-acquired. The most common source of infection was the urinary tract (62.9%). Of 240 patients, 65.8% fulfilled ≥ 2 SIRS criteria, and 60.4% had a total SOFA score of ≥ 2. Investigator-diagnosed sepsis and septic shock were reported in 72.1% and 10.0% of patients, respectively. The most common complication was kidney dysfunction (12.9%). The overall in-hospital mortality was 4.6%. Of 299 E. coli isolates tested, the resistance rates were: 30.4% for trimethoprim-sulfamethoxazole, 24.1% for ciprofloxacin, 22.1% for levofloxacin, 16.4% for ceftriaxone, 5.7% for cefepime, and 4.3% for ceftazidime.

CONCLUSIONS

The clinical profile of identified IED cases was characterized by high rates of sepsis. IED was associated with high rates of AMR to clinically relevant antibiotics. The identification of IED can be optimized by using a combination of clinical criteria (SIRS, SOFA, or qSOFA) and culture results.

Evaluation of Blood Culture Results in Patients with Malignancy in Erzurum Province, Turkey

Background

Bloodstream infections are a serious public health problem that requires follow-up with blood culture; this negatively affects the course of the disease and patient healthcare costs in patients with malignancy. This study aimed to determine the growth frequency of pathogens and their antibiotic resistance profiles in the blood cultures of patients with hematological and oncogenic malignancies.

Materials and methods

The results of 7451 blood cultures, obtained from 2926 patients between January 2017 and January 2022, were evaluated retrospectively. Of these cultures, 3969 were obtained from patients with malignancy (diagnostic codes C00-D48 in ICD-10) and 3482 from patients without malignancy. The hospital information management system modules were used to acquire patient data and blood culture results.

Results

Various microorganisms grew in 10.1% of blood cultures. Of these organisms, 64.1% were isolated from cases of malignancy. Of the pathogens, 49.2% were gram-negative bacteria, 47.7% were gram-positive bacteria, and 3.1% were fungi. The most frequently isolated bacteria were methicillin-resistant coagulase-negative staphylococci (3.2%), Escherichia coli (2.3%), Klebsiella pneumoniae (1.0%), methicillin-sensitive coagulase-negative staphylococci (0.7%), and Staphylococcus aureus (0.6%). Pathogen positivity was highest in the patient cultures with urinary system cancer (23.9%), thyroid and other endocrine gland cancers (20.6%), female and male genital organ cancers (18.2%/16.9%), and digestive organ cancer (14.2%). Gram-negative bacteria to ampicillin, piperacillin, and sulfamethoxazole-trimethoprim and Gram-positive bacteria to penicillin, erythromycin, and sulfamethoxazole-trimethoprim were highly resistant. Combined resistance to imipenem and meropenem was observed in 25 Gram-negative bacteria. Twelve (48%) of the carbapenem-resistant bacteria were isolated from patients with lymphoid, hematopoietic, and related tissue malignant neoplasia.

Conclusion

This study reported microorganisms and their antimicrobial resistance in the blood cultures of malignant patients, a special patient group. It pointed out that the antibiotic resistance of Staphylococcus, Klebsiella pneumoniae, and E. coli is high enough to cause problems in the treatment of patients with malignancy.

Empirical antibiotic therapy modalities for Enterobacteriaceae bloodstream infections in older patients and their impact on mortality: a multicentre retrospective study

PURPOSE

Enterobacteriaceae (EB) bloodstream infections (BSI) are frequent and serious in older patients. Physicians are faced with the dilemma of prescribing early appropriate empirical antibiotics to limit the risk of death, and sparing broad-spectrum antibiotic prescription. The aim of the study was to assess the rate of appropriate empirical antibiotics prescription to treat EB BSI in older patients and its impact on survival.

METHODS

This study conducted in 49 centres enrolled retrospectively up to the 10 last consecutive patients aged 75 years and over and treated for EB BSI. Factors related to in-hospital death were investigated using logistic regression.

RESULTS

Among the 487 enrolled patients (mean age 86 ± 5.9 years), 70% had at least one risk factor of being infected by third-generation cephalosporins (3GC)-resistant strain; however, only 13.8% of EB strains were resistant to 3GC. An empirical antimicrobial treatment was initiated for 418 patients (85.8%), and for 86% (n = 360/418) of them, it was considered appropriate. In-hospital mortality was 12.7% (n = 62) and was related to the severity of infection (OR 3.17, CI 95% 1.75-5.75), while a urinary portal of entry was protective (OR 0.34, CI 95% 0.19-0.60). Neither the absence of nor inappropriate empirical antibiotics prescription was associated with increased mortality.

CONCLUSION

While patients enrolled in this study were at risk of being infected by multidrug-resistant bacteria, yet mainly treated with 3GC, empirical antibiotics prescription was appropriate in most cases and did not influence mortality.

The critically ill older patient with sepsis: a narrative review

Sepsis is a significant public health concern, particularly affecting individuals above 70 years in developed countries. This is a crucial fact due to the increasing aging population, their heightened vulnerability to sepsis, and the associated high mortality rates. However, the morbidity and long-term outcomes are even more notable. While many patients respond well to timely and appropriate interventions, it is imperative to enhance efforts in identifying, documenting, preventing, and treating sepsis. Managing sepsis in older patients poses greater challenges and necessitates a comprehensive understanding of predisposing factors and a heightened suspicion for diagnosing infections and assessing the risk of sudden deterioration into sepsis. Despite age often being considered an independent risk factor for mortality and morbidity, recent research emphasizes the pivotal roles of frailty, disease severity, and comorbid conditions in influencing health outcomes. In addition, it is important to inquire about the patient's preferences and establish a personalized treatment plan that considers their potential for recovery with quality of life and functional outcomes. This review provides a summary of the most crucial aspects to consider when dealing with an old critically ill patient with sepsis.

Evaluation of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia: Epidemiology, clinical characteristics, and outcomes in the older patients in a tertiary teaching hospital in Malaysia

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is a major concern in the global healthcare system. However, data from Asian regions dealing with the singularity of this infection in older persons is lacking. We aimed to identify the differences in the clinical characteristics and outcomes of MRSA bacteremia between adults aged 18-64 and ≥ 65 years.

METHODS

A retrospective study cohort was conducted at the University Malaya Medical Centre (UMMC) on cases of MRSA bacteremia from 2012 to 2016. Patient demographic and clinical data were collected for risk factors analyses.

RESULTS

New cases of MRSA bacteremia showed a trend of increase from 0.12 to 100 admissions in 2012 to 0.17 per 100 admissions in 2016 but a drop was observed in 2014 (0.07 per 100 admissions). Out of the 275 patients with MRSA bacteremia, 139 (50.5%) patients were aged ≥ 65 years old. Co-morbidities and severity at presentation were significantly higher among older adults, including diabetes mellitus (p = 0.035), hypertension (p = 0.001), and ischemic heart disease (p < 0.001), as well as higher Charlson Comorbidity Index (p < 0.001) and Pitt bacteremia scores (p = 0.016). Central line-associated bloodstream infections were more common among younger patients (37.5% vs. 17.3% in older patients, p < 0.001), while skin and soft tissue infections are more frequent among older adults (20.9% vs. 10.3% in younger patients, p = 0.016). All-cause mortality and in-hospital mortality were significantly higher in older patients (82.7% and 56.1% vs. 63.2% and 28.7% in younger patients, p < 0.001). Multivariate analysis revealed age ≥ 65 years (adjusted odds ratio: 3.36; 95% confidence interval: 1.24-9.13), Pitt score ≥ 3 (2.15; 1.54-3.01), hospital (6.12; 1.81-20.72) and healthcare (3.19; 1.30-7.81) acquisition of MRSA, indwelling urinary catheters (5.43; 1.39-21.23), inappropriate targeted treatment (8.08; 1.15-56.86), lack of infectious disease team consultation (2.90; 1.04-8.11) and hypoalbuminemia (3.31; 1.25-8.79), were significant risk factors for 30-day mortality.

CONCLUSION

Older patients' risk of mortality from MRSA bacteremia was three times higher than younger patients. Our data will contribute to developing and validating a robust scoring system for risk-stratifying patients to achieve better management and improved clinical outcomes.

Outpatient Parenteral Antibiotic Therapy in Older Adults

Outpatient parenteral antimicrobial therapy (OPAT) for older adults is a complex process that involves multiple stakeholders and care coordination, but it is a useful and patient-centered tool with opportunities for the treatment of complicated infections, improved patient satisfaction, and reduced health-care costs. Older age should not be an exclusion for OPAT but rather prompt the OPAT provider to thoroughly evaluate candidacy and safety. Amid the on-going COVID-19 pandemic, innovations in OPAT are needed to shepherd OPAT care into a more patient-centered, thoughtful practice, whereas minimizing harm to older patients from unnecessary health-care exposure and thus health-care associated infections.

Outcomes and Predictors of In-Hospital Mortality among Older Patients with Dementia

Dementia is associated with high rates of admission to hospital, due to acute illness, and in-hospital mortality. The study aimed to investigate the impact of dementia on in-hospital mortality and identify the predictors of in-hospital mortality in these patients. This was a retrospective study evaluating all the patients ≥65 years consecutively admitted to our Emergency Department (ED). We compared the clinical outcomes of the patients with dementia at ED admission with those who did not have dementia, using a propensity score-matched (PSM) paired cohort of controls. The patients were matched for age, sex, Charlson Comorbidity Index value, and clinical severity at presentation (based on NEWS ≥ 5). The primary study endpoint was all-cause in-hospital death. After the PSM, a total of 7118 patients, 3559 with dementia and 3559 in the control group, were included in the study cohort. The mean age was 84 years, and 59.8% were females. The overall mortality rate was higher for the demented patients compared with the controls (18.7% vs. 16.0%, p = 0.002). The multivariate-adjusted hazard ratio (HR) showed that dementia was an independent risk factor for death (HR 1.13 [1.01−1.27]; p = 0.033). In the patients with dementia, respiratory failure (HR 3.08 [2.6−3.65]), acute renal failure (HR 1.64 [1.33−2.02]; p < 0.001), hemorrhagic stroke (HR 1.84 [1.38−2.44]; p < 0.001), and bloodstream infection (HR 1.41 [1.17−1.71]; p = 0.001) were significant predictors of worse outcomes. Finally, the comorbidities and severity of illness at ED admission negatively influenced survival among the patients with dementia (CCI HR 1.05 [1.01−1.1] p = 0.005; NEWS ≥ 5 HR 2.45 [1.88−3.2] p < 0.001). In conclusion, among the hospitalized older patients, dementia was associated with a higher risk of mortality. Furthermore, among the older patients with dementia, respiratory failure and bloodstream infections were independently associated with an increased risk of in-hospital mortality.

Effect of temperature on Escherichia coli bloodstream infection in a nationwide population-based study of incidence and resistance

BACKGROUND

The incidence of Escherichia coli bloodstream infections (BSI) is high and increasing. We aimed to describe the effect of season and temperature on the incidence of E. coli BSI and antibiotic-resistant E. coli BSI and to determine differences by place of BSI onset.

METHODS

All E. coli BSI in adult Israeli residents between January 1, 2018 and December 19, 2019 were included. We used the national database of mandatory BSI reports and outdoor temperature data. Monthly incidence and resistance were studied using multivariable negative binomial regressions with season (July-October vs. other) and temperature as covariates.

RESULTS

We included 10,583 events, 9012 (85%) community onset (CO) and 1571 (15%) hospital onset (HO). For CO events, for each average monthly temperature increase of 5.5 °C, the monthly number of events increased by 6.2% (95% CI 1.6-11.1%, p = 0.008) and the monthly number of multidrug-resistant events increased by 4.9% (95% CI 0.3-9.7%, p = 0.04). The effect of season was not significant. For HO events, incidence of BSI and resistant BSI were not associated with temperature or season.

CONCLUSION

Temperature increases the incidence of CO E. coli BSI and CO antibiotic-resistant E. coli BSI. Global warming threatens to increase the incidence of E. coli BSI.

FDG PET/CT in Cardiac Infection: Does It Matter? A Narrative Review

The limited performance of echocardiography in specific infectious processes involving the heart led to the search for additional diagnostic tools. Fluorodeoxyglucose positron emission tomography computed tomography (FDG PET/CT) has been proposed for its diagnostic abilities in several infectious diseases including cardiac infections. A literature review of studies evaluating FDG PET/CT in native valve infective endocarditis (IE), prosthetic valve IE, cardiac implantable electrical device (CIED) infection, and left ventricular assist device (LVAD) infection is presented, focusing on studies published in recent years. Overall, in prosthetic valve endocarditis (PVE), FDG PET/CT demonstrate high sensitivity (73-93%) and specificity (80-95%), while in native valve endocarditis (NVE) the sensitivity is very low (22-68%), with high specificity (97-100%) similar to PVE. For CIED, LVAD infection, and transcatheter aortic valve implantation associated endocarditis, data come from small studies and show good diagnostic performance of FDG PET/CT. International guidelines are increasingly recommending FDG PET/CT for the diagnosis of specific conditions of cardiac infections. Beyond the diagnostic performance ability, few studies have evaluated the added benefit of FDG PET/CT in terms of clinical outcomes of patients with suspected cardiac infection. This should be the focus in future studies.

Prognostic Effects of Inappropriate Empirical Antimicrobial Therapy in Adults With Community-Onset Bacteremia: Age Matters

Background

Studies have reported the effects of delayed administration of appropriate antimicrobial therapy (AAT) on the short-term prognosis of patients with bloodstream infections; however, whether there is an age-related difference in these effects remains debated.

Methods

In this 4-year multicenter case-control study, patients with community-onset bacteremia were retrospectively categorized into the "middle-aged" (45-64 years), "old" (65-74 years), and "very old" (≥75 years) groups. Two methods were adopted to investigate the prognostic effects of delayed AAT in each age group. First, its effects were, respectively, investigated, after adjustment for the independent predictors of 30-day mortality. Second, patients in each age group were matched by the closest propensity-score (PS), which was calculated by independent predictors of mortality; the survival curves and Pearson chi-square tests were adopted to disclose its effects in each PS-matching group.

Results

Each hour of delayed AAT resulted in an average increase in the 30-day crude mortality rate of 0.2% (P = 0.03), 0.4% (P < 0.001), and 0.7% (P < 0.001) in middle-aged (968 patients), old (683), and very old (1,265) patients, after, respectively, adjusting the independent predictors of mortality in each group. After appropriate PS-matching, no significant proportion differences in patient demographics, bacteremia characteristics, severity of bacteremia and comorbidities, and 15-day or 30-day crude mortality rates were observed between three matched groups (582 patients in each group). However, significant differences in survival curves between patients with delayed AAT > 24 or >48 h and those without delayed administration were demonstrated in each age group. Furthermore, the odds ratios of 30-day mortality for delayed AAT > 24 or >48 h were 1.73 (P = 0.04) or 1.82 (P = 0.04), 1.84 (P = 0.03) or 1.95 (P = 0.02), and 1.87 (P = 0.02) or 2.34 (P = 0.003) in the middle-aged, old, and very old groups, respectively. Notably, the greatest prognostic impact of delayed AAT > 24 or >48 h in the very old group and the smallest impact in the middle-aged group were exhibited.

Conclusion

For adults (aged ≥45 years) with community-onset bacteremia, the delayed AAT significantly impacts their short-term survival in varied age groups and the age-related differences in its prognostic impact might be evident.

Trends in Incidence and Outcomes of Hospitalizations for Urinary Tract Infection among Older People in Spain (2001-2018)

(1) Background: To assess time trends in the incidence and in-hospital outcomes of urinary tract infection (UTI) in older people (≥65 years) in Spain (2001–2018) according to sex and to identify the factors independently associated with in-hospital mortality (IHM). (2) Methods: Using the Spanish National Hospital Database, we analyzed comorbidity, procedures, diagnosis, isolated microorganisms, and outcomes. (3) Results: We included 583,693 admissions (56.76% women). In both sexes, the incidence increased with age over time (p < 0.001). In men and women, the highest IHM was found among the oldest patients (>84 years) with values of 9.16% and 8.6%, respectively. The prevalence of bacteremia increased from 4.61% to 4.98% from 2001 to 2018 (p < 0.001) and sepsis decreased from 3.16% to 1.69% (p < 0.001). The risk of dying increased with age (>84 years) (OR 3.63; 95% CI 3.5–3.78) and with almost all comorbidities. Urinary catheter was a risk factor for women (OR 1.1; 95% CI 1.02–1.18) and protective for men (OR 0.71; 95% CI 0.66–0.76). Isolation of Staphylococcus aureus increased the risk of IHM by 40% among men (OR 1.4; 95% CI 1.28–1.53). After adjusting for confounders, IHM decreased over time. (4) Conclusions: The incidence of UTIs was higher in older patients and increased over time; however, IHM decreased during the same period. Female sex, age, comorbidities, sepsis, and a Staphylococcus aureus isolation increased risk of IHM.

Burden of bloodstream infection in older persons: a population-based study

BACKGROUND

Advancing age is a major risk factor for developing and dying from bloodstream infections (BSI). However, there is a paucity of population-based studies investigating the epidemiology of BSI in older persons.

OBJECTIVE

To define the incidence, clinical determinants, and risk factors for death among those aged 65 years and older with BSI.

METHODS

Population-based surveillance was conducted in the western interior of British Columbia, Canada, between April 1, 2010 and March 31, 2020. Chart reviews were conducted for clinical details and all cause case-fatality was established at 30-days follow-up.

RESULTS

A total of 1854 incident BSI were identified among 1657 individuals aged 65 and older for an annual incidence of 533.9 per 100,000 population; the incidence for those aged 65-74, 75-84, and ≥85 years was 375.3, 678.9, and 1046.6 per 100,000 population, respectively. Males were at significantly increased risk as compared to females (incidence rate ratio, IRR 1.44; 95% confidence interval, CI, 1.32-1.59; p<0.0001). The crude annual incidence increased by 50% during the study. However, this was related to shift in population demographics with no increase evident following age- and sex-standardization. Older patients were more likely to have healthcare-associated infections and genitourinary sources and less likely to have bone/joint or soft tissue infections. The proportion of patients with underlying congestive heart failure, stroke, and dementia increased, whereas diabetes and liver disease decreased with older age. The overall 30-day all cause case-fatality rate was 22.0% (364/1657). After adjustment for clinical focus, onset of infection, etiology, and co-morbidity in a logistic model, those aged 75-84 years (odds ratio, OR, 1.66; 95% CI, 1.25-2.21) and ≥ 85 years (OR, 1.98; 95% CI, 1.41-2.77) were at significantly increased risk for death as compared to those aged 65-74 years.

CONCLUSION

Bloodstream infection is common in older persons and is a major cause of death. Countries with aging populations worldwide should expect an increase burden associated with BSI in the coming years.

Bacterial behavior in human blood reveals complement evaders with some persister-like features

Bacterial bloodstream infections (BSI) are a major health concern and can cause up to 40% mortality. Pseudomonas aeruginosa BSI is often of nosocomial origin and is associated with a particularly poor prognosis. The mechanism of bacterial persistence in blood is still largely unknown. Here, we analyzed the behavior of a cohort of clinical and laboratory Pseudomonas aeruginosa strains in human blood. In this specific environment, complement was the main defensive mechanism, acting either by direct bacterial lysis or by opsonophagocytosis, which required recognition by immune cells. We found highly variable survival rates for different strains in blood, whatever their origin, serotype, or the nature of their secreted toxins (ExoS, ExoU or ExlA) and despite their detection by immune cells. We identified and characterized a complement-tolerant subpopulation of bacterial cells that we named “evaders”. Evaders shared some features with bacterial persisters, which tolerate antibiotic treatment. Notably, in bi-phasic killing curves, the evaders represented 0.1–0.001% of the initial bacterial load and displayed transient tolerance. However, the evaders are not dormant and require active metabolism to persist in blood. We detected the evaders for five other major human pathogens: Acinetobacter baumannii, Burkholderia multivorans, enteroaggregative Escherichia coli, Klebsiella pneumoniae, and Yersinia enterocolitica. Thus, the evaders could allow the pathogen to persist within the bloodstream, and may be the cause of fatal bacteremia or dissemination, in particular in the absence of effective antibiotic treatments.

Blood infections by antibiotic resistant bacteria, notably Pseudomonas aeruginosa, are major concerns in hospital settings. The complex interplay between P. aeruginosa and the innate immune system in the context of human blood is still poorly understood. By studying the behavior of various P. aeruginosa strains in human whole blood and plasma, we showed that bacterial strains display different rate of tolerance to the complement system. Despite the complement microbicide activity, most bacteria withstand elimination through phenotypic heterogeneity creating a tiny (<0.1%) subpopulation of transiently tolerant evaders able to persist in plasma. This phenotypic heterogeneity thus prevents total elimination of the pathogen from the circulation, and represents a new strategy to disseminate within the organism.