ABSTRACT
Since its isolation in 1988, Afipia felis has been associated with cat scratch disease (CSD) in only one report and its role in CSD has been questioned. We have cultured A. felis from a lymph node of a patient with CSD. 16S rRNA gene sequencing, DNA relatedness studies, fatty acid analysis, and PCR of the A. felis ferredoxin gene showed that the isolate is identical to the previously reported A. felis isolate. To determine the role of A. felis in CSD, PCR of the 16S rRNA gene followed by hybridizations with specific probes were performed with lymph node specimens from CSD patients. All 32 specimens tested positive for Bartonella henselae and negative for A. felis. We conclude that A. felis is a rare cause of CSD. Diagnostic tests not conducive to the identification of A. felis might cause the diagnosis of CSD due to A. felis to be missed.
Subject(s)
Cat-Scratch Disease/diagnosis , Gram-Negative Bacteria/isolation & purification , Adult , Animals , Cat-Scratch Disease/microbiology , Cats , DNA Primers , DNA, Ribosomal/genetics , Female , Gram-Negative Bacteria/classification , Gram-Negative Bacteria/genetics , Humans , Lymph Nodes/microbiology , Oligonucleotide Probes , Phenotype , Polymerase Chain Reaction/methods , RNA, Ribosomal, 16S/geneticsABSTRACT
Amplification of Bartonella henselae DNA has been proposed as a diagnostic test for cat scratch disease (CSD). The sensitivities of the following three PCR assays were compared. PCR/rRNA with universal primers amplifies part of the 16S rRNA gene, followed by hybridization with a specific B. henselae probe; PCR/CS and PCR/HSP amplify portions of the gltA and the htrA genes, respectively, each followed by restriction fragment length polymorphism analysis. The threshold of detection of B. henselae DNA in pus was 10(-4), 10(-3), and 10(-2) ng for PCR/rRNA, PCR/CS, and PCR/HSP, respectively. By these three assays, B. henselae DNA was detected in 100, 94, and 69% of 32 pus and lymph node specimens from CSD patients, respectively. The similar sensitivities of the PCR/rRNA and the PCR/CS assays for detecting B. henselae DNA in clinical specimens are in contrast to the 10-fold difference in sensitivities in favor of PCR/rRNA demonstrated with purified B. henselae DNA in sterile pus, suggesting that in the majority of cases, the bacterial load in clinical specimens is large enough to be identified by the PCR/CS assay. A two-step approach is suggested to achieve maximal sensitivity for detecting B. henselae in clinical specimens: initial testing by PCR/CS (which does not require hybridization), followed by PCR/rRNA with PCR/CS-negative specimens when CSD is strongly suspected.
