IDENTIFICATION OF BARTONELLA (ROCHALIMAEA) SPECIES AMONG FASTIDIOUS GRAM-NEGATIVE BACTERIA ON THE BASIS OF THE PARTIAL SEQUENCE OF THE CITRATE-SYNTHASE GENE

The bacterial genus Bartonella (Rochalimaea) includes emerging human p athogens with five recognized species. These are fastidious gram-negat ive bacteria, exhibiting few phenotypic characteristics and whose iden tification relies upon serotyping, cellular fatty acid analysis, and m olecular typing. Most of the isolates have been recovered from the blo od of patients, and three of the four pathogenic Bartonella species ar e associated with infectious endocarditis. We performed PCR-restrictio n fragment length polymorphism (RFLP) analysis of the blood culture bo ttle supernatant for the routine identification of Bartonella species among fastidious gram-negative bacteria. The amplification of the citr ate-synthase gene with primers previously reported (R. L. Regnery, C. L. Spruill, and B. D. Plikaytis, J. Bacteriol. 173:1576-1589, 1991) yi elded a 379-bp product from Bartonella species and a 382-bp product fo r Capnocytophaga ochracea but no product from any of the other 15 geno typically or phenotypically related species tested. We determined the sequences of the citrate-synthase gene-amplified products for Bartonel la species and C. ochracea in order to predict the optimal restriction enzyme to be used in RFLP analysis. TaqI and AciI allowed identificat ion of Bartonella species and C. ochracea. We propose that acridine or ange and Gram staining, followed by PCR-RFLP analysis of the blood bot tle supernatant, be included in the examination of blood samples from patients with suspected infectious endocarditis.