Syndrome of Rochalimaea henselae adenitis suggesting cat scratch disease

Objective: To describe a clinical syndrome of cat scratch disease caused by Rochalimaea henselae, including methods for isolation of the organism from tissue and for identification. Design: Case series. Setting: U.S. Air Force referral hospital infectious diseases clinic. Patients: Two previously healthy patients. Main Measurements and Results: Two immunocompetent patients who had handled cats developed unilateral upper-extremity adenitis associated with a distal papular lesion and fever. The adenitis and distal lesions persisted and progressively worsened. Cultures of the involved lymph nodes from both patients grew R. henselae, a recently described organism associated with bacillary angiomatosis and peliosis hepatis in human immunodeficiency virus-infected patients and with bacteremia in immunocompromised and immunocompetent hosts. The organism was characterized as oxidase negative and X-factor dependent and had a characteristic pattern in analysis of whole-cell fatty acids differing from Afipia felis, a bacterium that has been associated with cat scratch disease. The identity of the isolate was confirmed by analysis of whole-cell fatty acids using gas chromatography and by amplification of the citrate synthetase gene sequence and analysis of the polymerase chain reaction-amplified product. The organisms were broadly susceptible to a variety of antimicrobials by broth microdilution; however in-vitro resistance to first-generation cephalosporins correlated with clinical failure of therapy. Conclusion: Rochalimaea henselae can be a cause of cat scratch disease in immunocompetent patients.