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Endocarditis sustained by Streptococcus viridans with normal levels of procalcitonin: an unexpected finding
G Merra1, D Marsiliani, S Di Giambenedetto
1Department of Emergency Medicine, Catholic University of the Sacred Heart, School of Medicine, Rome, Italy. giuseppe.merra@policlinicogemelli.it.
Objective:
Procalcytonin is a useful marker of bacterial infections. Several studies have reported elevated serum levels of PCT in patients with infective endocarditis (IE) and/or other infections sustained by cocci. We report a rare case of IE attributed to Streptococcus viridans in whom levels of PCT were normal.
Case Report:
A 67 years-old male was admitted to the Emergency Department for a 25-day history of recurring night fever. Upon admission, patient underwent blood test, including PCT, showing normal levels, except for a slight increased creatinine concentration (1.6 mg/dl). CBC showed WBC levels of 10.24 x 10^9/l with neutrophil concentration of 8.64 x 10^9/l. Three blood culture were performed, and all of them were positive for Streptococcus viridans (S. oralis). Dosage of PCT was then repeated two times within the next 2 days after the admission, with negative results. An echocardiogram was performed, showing a lesion of the left anterior aortic leaflet. This finding was confirmed by a transoesophageal echocardiogram. The patient was then treated with G penicillin (6 million of Units quid) for 3 weeks; during the course of antibiotic therapy fever disappeared and blood cultures become negative.
Conclusions:
In the literature, there are just few data about the association between PCT levels and endocarditis and sepsis but there are not etiological differentiations particularly for those sustained by Streptococcus viridans. Only one study suggests that a Streptococcus viridans' infection could reduce PCT accuracy in diagnosis oh endocarditis. So, our observation although come from a single case, could merits, further investigation.
Insights
Procalcitonin (PCT) is typically elevated in bacterial infections, but this case report highlights a rare instance of infective endocarditis caused by Streptococcus viridans with normal PCT levels. Further research is needed to understand PCT accuracy in specific bacterial endocarditis cases.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Biomarker Research
Background:
- Procalcitonin (PCT) is a widely recognized biomarker for bacterial infections, often showing elevated levels in conditions like infective endocarditis (IE).
- Previous studies indicate a correlation between PCT levels and the presence of bacterial infections, including those caused by cocci.
Observation:
- A 67-year-old male presented with fever and was diagnosed with IE caused by Streptococcus viridans.
- Despite the bacterial infection, the patient exhibited consistently normal procalcitonin levels throughout his admission.
- Diagnostic imaging confirmed a lesion on the aortic leaflet, consistent with infective endocarditis.
Findings:
- This case presents a rare scenario where infective endocarditis due to Streptococcus viridans was associated with normal procalcitonin levels.
- The findings challenge the typical interpretation of PCT as a universal indicator of bacterial IE, particularly in specific etiological contexts.
Implications:
- This case suggests that Streptococcus viridans endocarditis may not consistently elevate procalcitonin, potentially impacting diagnostic accuracy.
- Further investigation is warranted to explore the variability of PCT response in different bacterial causes of endocarditis.
- Clinicians should consider the specific pathogen when interpreting PCT levels in suspected IE cases.