Bartonella henselae DNA in Seronegative Patients with Cat-Scratch Disease

Abstract

Cat-scratch disease（CSD）is a worldwide zoonosis caused by Bartonella henselae. Because isolation of B. henselae by culture is difficult, the standard laboratory diagnosis of CSD is serological tests using indirect fluorescent antibody assay（IFA）．Detection of B. henselae DNA by PCR is also examined when lymph nodes are obtained. Isolation of B. henselae DNA from blood specimens of CSD patients has been sporadically described. However, the usefulness of serological tests, coupled with the detection of B. henselae DNA from blood specimens, is not well described. We examined 80 patients with suspected CSD using IFA and real-time PCR（rPCR）on blood specimens, to confirm the clinical utility of the combined use of both assays. Of the 80 patients with suspected CSD, 17（21.3%）were positive by IFA and 11（13.8%）were positive by rPCR. Six patients were positive by both assays. CSD detection sensitivity increased from 21.3%（17/80）using IFA alone to 27.5%（22/80）with combined use of IFA and rPCR on blood specimens because B. henselae DNA was detected in 7.9%（5/63）of blood specimens from seronegative patients. The combined use of serological tests and rPCR on blood specimens is recommended for the prompt, noninvasive laboratory diagnosis of CSD.