Shift in bacterial etiology from the CAPNETZ cohort in patients with community-acquired pneumonia: data over more than a decade

[Update on pneumonia-Clinical management 2025 in consideration of the current guidelines]

Pneumonia is one of the most frequent infectious diseases that lead to hospitalization. It is a decisive turning point and frequently leads to death, particularly in old and comorbid people (so-called terminal event). It is classified into community-acquired pneumonia, hospital-acquired pneumonia and pneumonia due to severe immunosuppression. The three entities differ especially in the spectrum of pathogens to be expected, the site of development and therefore in the calculated anti-infective treatment and initial diagnostics. The continuous re-evaluation of the course and the focal points as well as adaptation of the treatment are essential for the optimal outcome of the patient. Even after surviving an acute disease, in cases of possibly deteriorated functional status there is a need for good aftercare with management of comorbidities, social interventions and when necessary, treatment of persisting organ dysfunction. Prophylaxis by vaccination is essential.

Clinical Features, Diagnostics, Etiology, and Outcomes of Hospitalized Solid Organ Recipients With Community-Acquired Pneumonia: A Retrospective Cohort Analysis

BACKGROUND

Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality worldwide. Limited evidence is available on the most effective diagnostic approaches, management strategies, and long-term outcomes for CAP in patients who have undergone solid organ transplantation.

RESEARCH QUESTION

What is the acute and long-term morbidity and mortality after CAP in organ transplant recipients?

STUDY DESIGN AND METHODS

We retrospectively analyzed hospitalizations for CAP in solid organ recipients at the largest German transplant center. The study included patients admitted between January 1, 2010, and May 31, 2021. The reported outcomes are in-hospital and 1-year mortality, risk of cardiovascular events during hospitalization and at 1 year, admission to the ICU, and risk of pneumonia with Pseudomonas aeruginosa. Multivariable binary logistic regression using stepwise forward selection was performed to determine predictive factors for pneumonia with P aeruginosa.

RESULTS

We analyzed data from 403 hospitalizations of 333 solid organ recipients. In > 60% of cases, patients had multiple comorbidities, with cardiovascular and chronic kidney disease being the most prevalent. More than one-half of the patients required oxygen supplementation after admission. In-hospital mortality (13.2%) and the death rate at 1 year postevent (24.6%) were higher than data reported from immunocompetent patients. We also observed high rates of acute cardiovascular events and events occurring 1 year after admission. Early blood cultures and bronchoscopy in the first 24 h significantly increased the odds of establishing an etiology. In our low-resistance setting, the burden of antimicrobial resistance was driven by bacteria from chronically colonized patients, mostly lung transplant recipients.

INTERPRETATION

This comprehensive analysis highlights the high morbidity associated with CAP after transplantation. It also emphasizes the need for prospective multicenter studies to guide evidence-based practices and improve outcomes for these vulnerable patients.

Microbial aetiology of community-acquired pneumonia in hospitalised adults: A prospective study utilising comprehensive molecular testing

OBJECTIVES

This study aimed to describe the microbial aetiology of community-acquired pneumonia (CAP) in adults admitted to a tertiary care hospital and assess the impact of syndromic polymerase chain reaction (PCR) panels on pathogen detection.

METHODS

Conducted at Haukeland University Hospital, Norway, from September 2020 to April 2023, this prospective study enrolled adults with suspected CAP. We analysed lower respiratory tract samples using both standard-of-care tests and the BIOFIRE® FILMARRAY® Pneumonia Plus Panel (FAP plus). The added value of FAP Plus in enhancing the detection of clinically relevant pathogens, alongside standard-of-care diagnostics, was assessed.

RESULTS

Of the 3238 patients screened, 640 met the inclusion criteria, with 384 confirmed to have CAP at discharge. In these patients, pathogens with proven or probable clinical significance were identified in 312 (81.3%) patients. Haemophilus influenzae was the most prevalent pathogen, found in 118 patients (30.7%), followed by SARS-CoV-2 in 74 (19.3%), and Streptococcus pneumoniae in 64 (16.7%). Respiratory viruses were detected in 186 (48.4%) patients. The use of FAP plus improved the pathogen detection rate from 62.8% with standard-of-care methods to 81.3%.

CONCLUSIONS

Pathogens were identified in 81% of CAP patients, with Haemophilus influenzae and respiratory viruses being the most frequently detected pathogens. The addition of the FAP plus panel, markedly improved pathogen detection rates compared to standard-of-care diagnostics alone.

Exploring the microbial landscape: uncovering the pathogens associated with community-acquired pneumonia in hospitalized patients

Objectives

This study aimed to investigate the etiology, clinical features, and outcomes of community-acquired pneumonia (CAP) in adults. Understanding the causative pathogens is essential for effective treatment and prevention.

Design

Between 2016-2018, 518 hospitalized adults with CAP and 241 controls without symptoms were prospectively enrolled. Urine samples were collected for pneumococcal urinary antigen tests and nasopharyngeal swabs for viral and bacterial analysis, combined with routine diagnostic care.

Results

Among the included CAP patients, Streptococcus pneumoniae was the most common pathogen, detected in 28% of patients, followed by Haemophilus influenzae in 16%. Viruses were identified in 28%, and concurrent viruses and bacteria were detected in 15%. There was no difference in mortality, length of stay, or symptoms at hospitalization when comparing patients with bacterial, viral, or mixed etiologies. Among the control subjects without respiratory symptoms, S. pneumoniae, H. influenzae, or Moraxella catarrhalis were detected in 5-7%, and viruses in 7%.

Conclusion

Streptococcus pneumoniae emerged as the predominant cause of CAP, followed closely by viruses and H. influenzae. Intriguingly, symptoms and outcome were similar regardless of etiology. These findings highlight the complexity of this respiratory infection and emphasize the importance of comprehensive diagnostic and treatment strategies.Clinical Trial Registration: ClinicalTrials.gov, identifier [NCT03606135].

The role of vaccination in COPD: influenza, SARS-CoV-2, pneumococcus, pertussis, RSV and varicella zoster virus

Exacerbations of COPD are associated with worsening of the airflow obstruction, hospitalisation, reduced quality of life, disease progression and death. At least 70% of COPD exacerbations are infectious in origin, with respiratory viruses identified in approximately 30% of cases. Despite long-standing recommendations to vaccinate patients with COPD, vaccination rates remain suboptimal in this population.Streptococcus pneumoniae is one of the leading morbidity and mortality causes of lower respiratory tract infections. The Food and Drug Administration recently approved pneumococcal conjugate vaccines that showed strong immunogenicity against all 20 included serotypes. Influenza is the second most common virus linked to severe acute exacerbations of COPD. The variable vaccine efficacy across virus subtypes and the impaired immune response are significant drawbacks in the influenza vaccination strategy. High-dose and adjuvant vaccines are new approaches to tackle these problems. Respiratory syncytial virus is another virus known to cause acute exacerbations of COPD. The vaccine candidate RSVPreF3 is the first authorised for the prevention of RSV in adults ≥60 years and might help to reduce acute exacerbations of COPD. The 2023 Global Initiative for Chronic Lung Disease report recommends zoster vaccination to protect against shingles for people with COPD over 50 years.

[Antibiotic treatment of community-acquired and hospital-acquired pneumonia]

Community-acquired and nosocomial bacterial pneumonia are among the most common infectious diseases in Germany. Knowledge of possible pathogens and therapeutic implications thereof are essential to be able to provide adequate, differentiated antimicrobial therapy with the appropriate drugs, form of application, dose, and duration. New diagnostics that include multiplex polymerase chain reaction, correct interpretation of the biomarker procalcitonin, and treatment of multidrug-resistant bacteria are becoming increasingly import.

[Community-acquired pneumonia]

RISK FACTORS FOR SEVERE COURSES

The CRB-65 score is recommended as a risk predictor, as well as consideration of unstable comorbidities and oxygenation.

GROUPING OF COMMUNITY-ACQUIRED PNEUMONIA

Community-acquired pneumonia is divided into 3 groups: mild pneumonia, moderate pneumonia, severe pneumonia. Whether there is a curative vs palliative treatment goal should be determined early.

DIAGNOSTIC RECOMMENDATION

An X-ray chest radiograph is recommended to confirm the diagnosis, also in the outpatient setting if possible. Sonography of the thorax is an alternative, asking for additional imaging if negative. Streptococcus pneumoniae remains the most common bacterial pathogen.

THERAPY

Community-acquired pneumonia continues to be associated with high morbidity and lethality. Prompt diagnosis and prompt initiation of risk-adapted antimicrobial therapy are essential measures. However, in times of COVID-19, as well as the current influenza and RSV epidemic, purely viral pneumonias must also be expected. At least with COVID-19, antibiotics can often be avoided. Antiviral and anti-inflammatory drugs are used here.

POST-ACUTE COURSE

Patients after community-acquired pneumonia have increased acute and long-term mortality due to cardiovascular events in particular. The focus of research is on improved pathogen identification, a better understanding of the host response with the potential of developing specific therapeutics, the role of comorbidities, and the long-term consequences of the acute illness.

Development and Validation of a Sensitive and Robust Multiplex Antigen Capture Assay to Quantify Streptococcus pneumoniae Serotype-Specific Capsular Polysaccharides in Urine

Streptococcus pneumoniae is a major cause of community-acquired pneumonia (CAP) in young children, older adults, and those with immunocompromised status. Since the introduction of pneumococcal vaccines, the burden of invasive pneumococcal disease caused by vaccine serotypes (STs) has decreased; however, the effect on the burden of CAP is unclear, potentially due to the lack of testing for pneumococcal STs. We describe the development, qualification, and clinical validation of a high-throughput and multiplex ST-specific urine antigen detection (SSUAD) assay to address the unmet need in CAP pneumococcal epidemiology. The SSUAD assay is sensitive and specific to the 15 STs in the licensed pneumococcal conjugate vaccine V114 (STs 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F, and 33F) and uses ST-specific monoclonal antibodies for rapid and simultaneous quantification of the 15 STs using a Luminex microfluidics system. The SSUAD assay was optimized and qualified using healthy adult urine spiked with pneumococcal polysaccharides and validated using culture-positive clinical urine samples (n = 34). Key parameters measured were accuracy, precision, sensitivity, specificity, selectivity, and parallelism. The SSUAD assay met all prespecified validation acceptance criteria and is suitable for assessments of disease burden associated with the 15 pneumococcal STs included in V114.

IMPORTANCEStreptococcus pneumoniae has more than 90 serotypes capable of causing a range of disease manifestations, including otitis media, pneumonia, and invasive diseases, such as bacteremia or meningitis. Only a minority (<10%) of pneumococcal diseases are bacteremic with known serotype distribution. Culture and serotyping of respiratory specimens are neither routine nor reliable. Hence, the serotype-specific disease burden of the remaining (>90%) noninvasive conditions is largely unknown without reliable laboratory techniques. To address this need, a 15-plex urine antigen detection assay was developed and validated to quantify pneumococcal serotype-specific capsular polysaccharides in urine. This assay will support surveillance to estimate the pneumococcal disease burden and serotype distribution in nonbacteremic conditions. Data obtained from this assay will be critical for understanding the impact of pneumococcal vaccines on noninvasive pneumococcal diseases and to inform the choice of pneumococcal serotypes for next-generation vaccines.

A Case Report and Review of the Literature: Infectious Aneurysm Formation in the Pulmonary Arteries-A Rare but Perilous Sequela of Persisting Infection With Klebsiella pneumoniae

Septic aneurysms of the pulmonary artery are rare conditions, with few cases having been reported worldwide. They are assumed to result from septic emboli that cause a local inflammatory reaction of the arterial wall, ultimately leading to degenerative changes. We report the case of a 63-year-old female patient presenting with Klebsiella pneumoniae urosepsis and first diagnosis of diabetes mellitus, who developed a life-threatening infectious pulmonary artery aneurysm secondary to bacteremia with Klebsiella pneumoniae. The patient required a lobectomy due to pulmonary hemorrhage. We review the clinical hallmarks of Klebsiella pneumoniae related septic pulmonary embolic disease and summarize currently known risk factors for the development of infectious aneurysmatic disease including diabetes mellitus and other states of immunosuppression. The featured case aims to increase the awareness for this seldom but life-threatening complication of infectious diseases such as Klebsiella pneumoniae urosepsis.

Pneumococcal vaccination rates in immunocompromised patients in Germany: A retrospective cohort study to assess sequential vaccination rates and changes over time

Background

Pneumococcal vaccination is recommended by the German Standing Committee on Vaccination (STIKO) for infants, elderly 60+ years and patients at risk. In 2016, a sequential pneumococcal vaccination schedule (conjugate vaccine followed by polysaccharide vaccine 6–12 months later) supplemented this recommendation for immunocompromised patients ≥2 years of age. Previous research showed low pneumococcal vaccination rates (pnc-VR) in this vulnerable group. Moreover, no evidence is available on adherence to the newer sequential schedule. This study aimed to analyze the development of pnc-VRs in immunocompromised patients and rates of sequential vaccinations according to the STIKO recommendations.

Methods

Using a representative health claims database, we assigned incident immunocompromised patients ≥2 years of age to one of two successive cohorts to observe trends over time: cohort A (first diagnosis of immunocompromised condition between 01/2013 and 12/2014), and cohort B (first diagnosis between 01/ 2015 and 12/2017). Pnc-VR within two years after first diagnosis and cumulative pnc-VR was compared among both cohorts. In cohort B, we assessed sequential pnc-VR within 15 months of the first vaccination. For additional analyses, patients were stratified by age, gender and immunocompromising condition.

Results

Cohort A and B comprised 193,521 and 289,279 patients, respectively. Overall pnc-VR increased over time from 4.3% (cohort A; 95%-confidence interval: 4.3%-4.4%) to 6.0% (cohort B; 5.9%-6.1%), with highest pnc-VRs in men ≥60 years (11.3%: 11.1%-11.6%) and HIV patients (15.2%: 13.1%-17.4%). Cumulative pnc-VRs in cohort B were higher in any quarter following diagnosis when compared with cohort A. Overall sequential pnc-VR in cohort B was 4.0% (3.7%-4.3%), with a higher rate observed in patients aged 16–59 (6.8%: 6.0%-7.7%) vs. patients aged ≥60 years (3.1%: 2.8%-3.4%).

Conclusion

While some improvements were seen over time, pnc-VRs remain very low in immunocompromised patients, as did sequential vaccination rates. Current recommendations to protect immunocompromised patients from pneumococcal infections are not being sufficiently implemented.

Diagnostic stewardship aiming at expectorated or induced sputum promotes microbial diagnosis in community-acquired pneumonia

Purpose

Studies on aetiology of community-acquired pneumonia (CAP) vary in terms of microbial sampling methods, anatomical locations, and laboratory analyses, since no gold standard exists. In this large, multicentre, retrospective, regional study from Norway, our primary objective was to report the results of a strategic diagnostic stewardship intervention, targeting diagnostic yield from lower respiratory tract sampling. The secondary objective was to report hospitalized CAP aetiology and the diagnostic yield of various anatomical sampling locations.

Methods

Medical records from cases diagnosed with hospitalized CAP were collected retrospectively from March throughout May for three consecutive years at six hospitals. Between year one and two, we launched a diagnostic stewardship intervention at the emergency room level for the university teaching hospital only. The intervention was multifaceted aiming at upscaling specimen collection and enhancing collection techniques. Year one at the interventional hospital and every year at the five other emergency hospitals were used for comparison.

Results

Of the 1280 included cases of hospitalized CAP, a microbiological diagnosis was established for 29.1% among 1128 blood cultures and 1444 respiratory tract specimens. Blood cultures were positive for a pathogenic respiratory tract microbe in 4.9% of samples, whereas upper and lower respiratory tract samples overall provided a probable microbiological diagnosis in 21.3% and 47.5%, respectively. Expectorated or induced sputum overall provided aetiology in 51.7% of the samples. At the interventional hospital, the number of expectorated or induced sputum samples were significantly increased, and diagnostic yield from expectorated or induced sputum was significantly enhanced from 41.2 to 62.0% after the intervention (p = 0.049). There was an over-representation of samples from the interventional hospital during the study period. Non-typeable Haemophilus influenza and Streptococcus pneumoniae accounted for 25.3% and 24.7% of microbiologically confirmed cases, respectively.

Conclusion

Expectorated or induced sputum outperformed other sampling methods in providing a reliable microbiological diagnosis for hospitalized CAP. A diagnostic stewardship intervention significantly improved diagnostic yield of lower respiratory tract sampling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07199-4.

[Prevention by vaccination of adult patients with pulmonary diseases]

The key priority in patients with chronic lung diseases is currently immunization against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); all vaccines approved for this showed high effectiveness against severe infections. For patients with chronic pulmonary diseases the recommendations by the Standing Committee on Vaccination include not only the standard vaccinations in adulthood but also the so-called indication vaccinations. These include vaccinations against pneumococci and influenza. Advances include the recent development of new pneumococcal conjugate vaccines containing additional serotypes and the recommendation of a more effective high-dose vaccine against influenza for persons over 60 years old. With the next scheduled booster vaccination against tetanus and diphtheria a combination vaccine with pertussis antigen should be used. For patients with chronic lung disease the herpes zoster vaccine is recommended over the age of 50 years.