Atypical endocarditis due to gram-negative bacillus transmitted by dog bite

Area of Science:

• Infectious Diseases
• Cardiology
• Microbiology

Background:

• Subacute bacterial endocarditis (SBE) typically presents with fever and characteristic cardiac murmurs.
• Early diagnosis is crucial for effective treatment and improved patient outcomes.

Observation:

• A case of SBE presented with hemoptysis and late-onset cardiac murmurs, notably lacking fever.
• The etiological agent identified was a fastidious, slow-growing, unclassified gram-negative bacterium, DF-2 (decarboxylase fermenter-2).
• The infection was linked to a dog bite, suggesting zoonotic transmission.

Findings:

• The atypical presentation, including absence of pyrexia and delayed murmur detection, posed a diagnostic challenge.
• DF-2, a bacterium not previously associated with endocarditis, was confirmed as the causative agent.
• Dog bites represent a potential transmission route for DF-2 endocarditis.

Implications:

• This case underscores the importance of considering atypical presentations of SBE in clinical practice.
• Awareness of DF-2 as a potential pathogen in endocarditis, especially following animal contact, is critical.
• Diagnostic vigilance is necessary when classic signs are absent, guiding appropriate microbiological investigations.