Free Access
Vet. Res.
Volume 40, Number 2, March-April 2009
Adaptative strategies of vector-borne pathogens to vectorial transmission
Number of page(s) 22
Published online 14 March 2009
How to cite this article Vet. Res. (2009) 40:29
How to cite this article: Vet. Res. (2009) 40:29
DOI: 10.1051/vetres/2009011


Ecological fitness and strategies of adaptation of Bartonella species to their hosts and vectors

Bruno B. Chomel1, Henri-Jean Boulouis2, Edward B. Breitschwerdt3, Rickie W. Kasten1, Muriel Vayssier-Taussat2, Richard J. Birtles4, Jane E. Koehler5 and Christoph Dehio6

1  Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
2  UMR BIPAR ENVA/AFSSA/INRA/UPVM, E' cole Nationale Vétérinaire d'Alfort, 7 avenue du Général de Gaulle, 94704 Maisons-Alfort, France
3  Center for Comparative Medicine and Transitional Research, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough St., Raleigh, NC 27606, USA
4  Department of Veterinary Pathology, Faculty of Veterinary Science, University of Liverpool, Leahurst, CH64 7TE, United Kingdom
5  Division of Infectious Diseases, University of California, San Francisco, 513 Parnassus Avenue, Room S-380, San Francisco, CA, 94143-0654, USA
6  Focal Area of Infection Biology Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland

Received 12 November 2008; accepted 12 March 2009; published online 14 March 2009

Abstract - Bartonella spp. are facultative intracellular bacteria that cause characteristic hostrestricted hemotropic infections in mammals and are typically transmitted by blood-sucking arthropods. In the mammalian reservoir, these bacteria initially infect a yet unrecognized primary niche, which seeds organisms into the blood stream leading to the establishment of a long-lasting intra-erythrocytic bacteremia as the hall-mark of infection. Bacterial type IV secretion systems, which are supra-molecular transporters ancestrally related to bacterial conjugation systems, represent crucial pathogenicity factors that have contributed to a radial expansion of the Bartonella lineage in nature by facilitating adaptation to unique mammalian hosts. On the molecular level, the type IV secretion system VirB/VirD4 is known to translocate a cocktail of different effector proteins into host cells, which subvert multiple cellular functions to the benefit of the infecting pathogen. Furthermore, bacterial adhesins mediate a critical, early step in the pathogenesis of the bartonellae by binding to extracellular matrix components of host cells, which leads to firm bacterial adhesion to the cell surface as a prerequisite for the efficient translocation of type IV secretion effector proteins. The beststudied adhesins in bartonellae are the orthologous trimeric autotransporter adhesins, BadA in Bartonella henselae and the Vomp family in Bartonella quintana. Genetic diversity and strain variability also appear to enhance the ability of bartonellae to invade not only specific reservoir hosts, but also accidental hosts, as shown for B. henselae. Bartonellae have been identified in many different blood-sucking arthropods, in which they are typically found to cause extracellular infections of the mid-gut epithelium. Adaptation to specific vectors and reservoirs seems to be a common strategy of bartonellae for transmission and host diversity. However, knowledge regarding arthropod specificity/restriction, the mode of transmission, and the bacterial factors involved in arthropod infection and transmission is still limited.

Key words: Bartonella / vector / ecological fitness / host adaptation / pathogenesis

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© INRA, EDP Sciences 2009