ORIGINAL INVESTIGATION Comparative microbiological features of Bartonella henselae infection in a dog with fever of unknown origin and granulomatous lymphadenitis Amandine Drut • Isabelle Bublot • Edward B. Breitschwerdt • Luc Chabanne • Muriel Vayssier-Taussat • Jean-Luc Cadore ´ Received: 29 September 2013 / Accepted: 25 November 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract We report the first documented case of Bar- tonella henselae infection in a dog from France and the first isolation of B. henselae from a dog with fever of unknown origin. This observation contributes to the ‘‘One Health’’ concept focusing on zoonotic pathogens emerging from companion animals. A 1-year-old female German shepherd dog was referred for evaluation of fever of unknown origin of 1 month duration. Diagnostic investigations confirmed diffuse pyogranulomatous lymphadenitis. The dog became afebrile, and lymph node size normalized in response to a 6-week course of doxycycline. Retrospectively, Bartonella DNA was amplified from an EDTA-anticoagulated blood sample obtained before antimicrobial therapy, with the gtlA fragment sharing 99 % identity with the 350-bp gtlA fragment of the B. henselae Houston-1 strain. The same strain was isolated in the blood of three healthy cats from the household. Two months after discontinuation of doxycycline, the dog experienced a febrile relapse. Bar- tonella DNA was again amplified from blood prior to and immediately after administration of a 6-week course azithromycin therapy. However, without administration of additional medications, PCR was negative 9 months after azithromycin therapy and the dog remains clinically heal- thy 12 months following the second course of antibiotics. The medical management of this case raises several clini- cally relevant comparative infectious disease issues, including the extent to which Bartonella spp. contribute to fever of unknown origin and pyogranulomatous inflam- matory diseases in dogs and humans, and the potential of doxycycline and azithromycin treatment failures. The possibility that dogs could constitute an underestimated reservoir for B. henselae transmission to people is also discussed. Keywords Bartonella henselae Á Cat-scratch disease Á Dog Á Fever of unknown origin Á Granulomatous lymphadenitis Introduction Bartonella henselae is a zoonotic Gram-negative alpha- Proteobacterium that is the primary, if not sole, etiological agent of cat-scratch disease (CSD). Although cats are considered to be the primary reservoir host for B. henselae, DNA of this bacterial species has been found in dogs, cows, horses, feral swine, marine mammals and sea turtles [1]. Similarly, although cat fleas (Ctenocephalides felis) are considered the primary vector for transmission to reservoir and potentially non-reservoir hosts such as dogs and humans, B. henselae DNA has been amplified from Ixodes A. Drut (&) Á I. Bublot Á J.-L. Cadore ´ Service de Pathologie Me ´dicale des Carnivores Domestiques, VetAgro Sup Lyon Campus Ve ´te ´rinaire, Universite ´ de Lyon, 1 avenue Bourgelat, 69280 Marcy l’Etoile, France e-mail: amandine.drut@vetagro-sup.fr E. B. Breitschwerdt Intracellular Pathogens Research Laboratory, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27607, USA L. Chabanne De ´partement des Animaux de Compagnie and Jeune Equipe He ´mopathoge `nes Vectorise ´s, VetAgro Sup Lyon Campus Ve ´te ´rinaire, Universite ´ de Lyon, 1 avenue Bourgelat, 69280 Marcy l’Etoile, France M. Vayssier-Taussat USC Bipar, INRA, 7 avenue du Ge ´ne ´ral de Gaulle, 94700 Maisons-Alfort, France 123 Med Microbiol Immunol DOI 10.1007/s00430-013-0318-x