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

Front Public Health. 2023 Dec 13:11:1258981. doi: 10.3389/fpubh.2023.1258981. eCollection 2023.

Abstract

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].

Keywords: CAP; ECAPS; Haemophilus influenzae; Moraxella catarrhalis; Mycoplasma pneumoniae; community acquired pneumonia; influenza virus; lower respiratory tract infection.

Publication types

  • Research Support, Non-U.S. Gov't
  • Comment

MeSH terms

  • Adult
  • Bacteriophages*
  • Case-Control Studies
  • Community-Acquired Infections* / drug therapy
  • Community-Acquired Infections* / epidemiology
  • Community-Acquired Infections* / microbiology
  • Hospitalization
  • Humans
  • Pneumonia, Bacterial* / drug therapy
  • Pneumonia, Bacterial* / epidemiology
  • Pneumonia, Bacterial* / microbiology
  • Respiratory Tract Infections*
  • Streptococcus pneumoniae
  • Treatment Outcome

Associated data

  • ClinicalTrials.gov/NCT03606135

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the Knut and Alice Wallenberg Foundation (KR; 2018.0318), Anna and Edwin Berger Foundation (KR), an unrestricted grant from Pfizer (KR and JA), Swedish Heart Lung Foundation (KR; #20180401, www.hjart-lungfonden.se), the Royal Physiographical Society in Lund (Forssman's Foundation), the Skåne County Council's research and development foundation (KR), and the Swedish Research Council (KR; #2019-01053, www.vr.se). One of the funding sources, Pfizer, was involved in laboratory analysis of UAD and Binax testing on urine samples. None of the funders had any role in study design, data interpretation, or writing of the report. KR reports an unrestricted grant from Pfizer during the conduct of the study outside the submitted work. The remaining authors have nothing to disclose.