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Primary Streptococcus viridans pneumonia
T K Sarkar1, R S Murarka, G L Gilardi
1Department of Medicine, North General Hospital, New York.
Abstract:
We describe three cases of acute uncomplicated bacterial pneumonia due to viridans streptococci in previously healthy adults, which were indistinguishable from those caused by other well-known respiratory pathogens. On arrival, all of these patients were treated with IV aqueous penicillin based on Gram stain of sputum which showed predominant Gram-positive cocci in pairs and chains. These specimens of sputum grew normal oral flora in the three cases. The diagnosis was confirmed by positive blood cultures in all three patients from each of two separate samples of blood. The isolates were identified as S uberis. There is no precedent in the literature of primary pneumonia due to viridans streptococci complicated by bacteremia in normal adults. We wonder if primary pneumonia due to viridans streptococci is not as rare as has been reported in the literature. Also, Gram stain of the sputum had a very significant contribution in the initial management of these patients. All of these patients subjectively showed improvement in 24 hours and became afebrile within three days of starting penicillin therapy.
Insights
Acute bacterial pneumonia caused by viridans streptococci is rare but treatable. This study highlights three cases in healthy adults, emphasizing prompt diagnosis and penicillin therapy for effective outcomes.
Area of Science:
- Infectious Diseases
- Microbiology
- Pulmonology
Background:
- Viridans streptococci are typically considered normal oral flora.
- Primary pneumonia due to viridans streptococci complicated by bacteremia in healthy adults is rarely reported.
- Distinguishing viridans streptococci pneumonia from other bacterial pneumonias can be challenging.
Purpose of the Study:
- To report three cases of acute uncomplicated bacterial pneumonia caused by viridans streptococci (specifically Streptococcus uberis) in previously healthy adults.
- To highlight the diagnostic and therapeutic implications of such infections.
- To question the reported rarity of primary viridans streptococci pneumonia.
Main Methods:
- Case series describing three adult patients with acute pneumonia.
- Diagnosis based on clinical presentation, sputum Gram stain, and positive blood cultures.
- Treatment with intravenous aqueous penicillin.
Main Results:
- All three patients presented with symptoms indistinguishable from common bacterial pneumonias.
- Sputum Gram stain showed Gram-positive cocci, but cultures revealed normal oral flora.
- Blood cultures confirmed viridans streptococci (S. uberis) bacteremia.
- Patients showed subjective improvement within 24 hours and became afebrile within three days of penicillin therapy.
Conclusions:
- Acute pneumonia due to viridans streptococci, even with bacteremia, can occur in healthy adults.
- Gram stain of sputum is crucial for initial management decisions.
- Prompt penicillin therapy appears effective for this condition, suggesting it may be underdiagnosed.