ABSTRACT Background Bartonella henselae is a fastidious gram-negative rod that can cause systemic disease in immunocompromised patients. Infection may be complicated by glomerulonephritis, often in the setting of culture-negative infective endocarditis. The histologic pattern of Bartonella -associated glomerulonephritis is variable and often difficult to distinguish from non-infectious causes of glomerulonephritis by histopathology. Prompt, accurate diagnosis is further complicated by the poor sensitivity of routine culture methods for the detection of B. henselae , and serology or adjunctive molecular testing is typically required for microbiologic diagnosis. Case Summary A middle-aged male renal transplant recipient was admitted to our hospital with fever, nausea, vomiting, diarrhea, and laboratory evidence of acute kidney injury. A thorough infectious disease work-up revealed markedly elevated B. henselae immunoglobulin G and immunoglobulin M titers and significant exposures to cats and fleas. A biopsy of the renal allograft revealed crescentic glomerulonephritis with immune complex deposition. No definitive evidence of infective endocarditis was found. The patient was started on renal replacement therapy and treated for disseminated bartonellosis with doxycycline and rifabutin. Conclusion The diagnosis of Bartonella -associated glomerulonephritis in immunocompromised patients can be challenging from both the clinical and histopathologic perspectives. A high degree of clinical suspicion in patients with relevant risk factors is important for prompt diagnosis and treatment. Regardless of the presence or absence of typical signs and symptoms of cat scratch disease and/or infective endocarditis, Bartonella spp. should be included in the differential diagnosis of glomerulonephritis in solid-organ transplant recipients and other immunocompromised patients with cats or other relevant exposures.
Schaack et al. (Tue,) studied this question.