Does primary Streptococcus viridans pneumonia exist?

Area of Science:

• Microbiology
• Infectious Diseases
• Pulmonology

Background:

• Community-acquired pneumonia (CAP) is a significant global health concern.
• Etiological diagnosis of CAP can be challenging, with a substantial proportion of cases remaining undiagnosed.
• The role of specific bacterial species, like viridans streptococci, in CAP is not fully elucidated.

Observation:

• Four adult patients presented with community-acquired pneumonia (CAP).
• Blood cultures consistently isolated Streptococcus viridans as the sole pathogen.
• Sputum cultures and Gram stains were negative in most cases; echocardiography ruled out endocarditis.

Findings:

• Streptococcus viridans was identified as the causative agent in these CAP cases.
• Radiographic findings included segmental or subsegmental consolidations, sometimes appearing mass-like.
• The absence of other microbiological findings highlights the significance of blood culture results.

Implications:

• Viridans streptococci may be an underrecognized cause of CAP.
• Clinicians should consider Streptococcus viridans in the differential diagnosis of CAP.
• Further research is warranted to understand the prevalence and clinical significance of viridans streptococci-associated pneumonia.