Case report: Bordetella holmesii: A rare pathogen causing infective endocarditis associated glomerulonephritis

Area of Science:

• Nephrology
• Cardiology
• Infectious Diseases

Background:

• Infective endocarditis (IE) can lead to severe complications including multiorgan dysfunction and chronic kidney disease.
• Acute glomerulonephritis is a potential, though often overlooked, manifestation of IE.
• Common IE pathogens include Staphylococcus and Streptococcus species.

Observation:

• A 20-year-old male with complex congenital heart disease (tetralogy of Fallot with pulmonary atresia) presented with symptoms of acute glomerulonephritis (edema, hematuria) five weeks after initial treatment for presumed streptococcal pharyngitis.
• Investigations revealed nephrotic range proteinuria, elevated creatinine, hematuria, and hypocomplementemia.
• Blood cultures and microbial cell-free DNA sequencing identified Bordetella holmesii as the causative agent, with a vegetation found on the prosthetic pulmonary valve.

Findings:

• Bordetella holmesii, a rare pathogen, was identified as the cause of infective endocarditis-associated glomerulonephritis.
• The patient's renal function recovered following a 6-week course of intravenous antibiotics and angiotensin receptor blockade.
• Hypocomplementemia and proteinuria significantly improved, indicating resolution of the glomerulonephritis.

Implications:

• This case underscores the importance of considering rare pathogens in infective endocarditis, especially in patients with cardiac conditions.
• Early diagnosis and comprehensive management of IE-associated glomerulonephritis are crucial for renal recovery and cardiac preservation.
• Microbial cell-free DNA sequencing can be a valuable tool in identifying causative agents in culture-negative or difficult-to-diagnose IE cases.