Native Aortic Valve Endocarditis Caused by Rothia mucilaginosa, Initially Misidentified as Neisseria sicca

Area of Science:

• Infectious Diseases
• Cardiology
• Microbiology

Background:

• Infective endocarditis (IE) is a serious heart valve infection, typically caused by Staphylococcus aureus or Streptococcus viridans.
• Atypical organisms, such as Rothia species (spp.), can also cause IE, particularly in patients with prosthetic valves.
• Native valve endocarditis due to Rothia spp. is uncommon.

Purpose of the Study:

• To report a case of native aortic valve subacute endocarditis caused by Rothia mucilaginosa.
• To emphasize the diagnostic challenge posed by atypical pathogens in infective endocarditis.
• To highlight the importance of considering IE in immunocompromised patients with unexplained fever.

Main Methods:

• Case report of a middle-aged, immunocompromised male patient.
• Diagnostic workup included physical examination, blood cultures, and transesophageal echocardiogram.
• Initial misidentification of the pathogen as Neisseria sicca, followed by re-identification as Rothia mucilaginosa.

Main Results:

• The patient presented with symptoms of fever, cough, and headache, later diagnosed with subacute infective endocarditis.
• Blood cultures initially identified Neisseria sicca, but were later re-identified as Rothia mucilaginosa.
• The patient experienced complications including intraparenchymal hemorrhage and embolic infarcts but eventually recovered.

Conclusions:

• Rothia mucilaginosa can cause subacute infective endocarditis, even on native aortic valves.
• Immunocompromised status and initial misidentification can complicate the diagnosis of IE.
• Infective endocarditis should remain a key differential diagnosis for patients presenting with fever of unknown origin.