[Bartonella infection in hematological practice]

AIM

To characterize the clinical and histological features of Bartonella infection in patients asking for hematological advice and to assess the significance of serological and molecular methods for the diagnosis of this infection.

MATERIALS AND METHODS

The case histories of 747 patients asking for advice at the Hematology Research Cancer, Russian Academy of Medical Sciences, for lymphadenopaphy were retrospectively studied. The study included 10 patients in whom Bartonella infection could be suspected. For verification of the diagnosis, the authors conducted a serological study of the patients' sera and a molecular study of archival paraffined lymph node biopsy specimens.

RESULTS

The study showed it possible to make a retrospective diagnosis of cat-scratch disease (CSD) by polymerase chain reaction (PCR) used in the study of archival lymph node biopsy specimens and stained preparations.

CONCLUSION

CSD should be suspected when a patient has sustained lymphadenopathy and a respective epidemiological history (feline contact). Bartonella infection should be diagnosed on the basis of a dynamic serological study and, if possible, PCR of cells from biopsy specimens of lymph nodes or the lesion developed at the site of Bartonella penetration into the human body (primary affect).

Bartonella quintana in cynomolgus monkey (Macaca fascicularis)

We identified a Bartonella quintana strain by polymerase chain reaction amplification, cloning, and sequencing of DNA extracted from lysed erythrocytes and cultured colonies grown from peripheral blood collected from a captive-bred cynomolgus monkey (Macaca fascicularis). This report describes naturally acquired B. quintana infection in a nonhuman primate.

A family of variably expressed outer-membrane proteins (Vomp) mediates adhesion and autoaggregation in Bartonella quintana

Bartonella species are fastidious, Gram-negative human pathogens that can persist in the host bloodstream for years and bind to and invade several types of host cells. For many pathogens, adhesion to host cells and extracellular matrix (ECM) components is a critical virulence determinant. Bacteria often vary expression of surface adhesins by phase or antigenic variation to subvert the host immune response and permit adaptive interaction with different host structures. We developed a macaque animal model for Bartonella quintana infection to detect changes in bacterial outer-membrane proteins (OMP) during prolonged bloodstream infection. We identified a gene family encoding four highly conserved, 100-kDa, variably expressed OMP (Vomp), two of which function as adhesins. The variable expression of Vomp family members appears to be mediated by deletion of one or more vomp genes during chronic bloodstream infection. vomp deletion was observed also in isolates from humans with chronic B. quintana infection. The Vomp are closely related to the afimbrial adhesin, YadA, a virulence factor of Yersinia enterocolitica. The surface-expressed Vomp contain conserved structural features of YadA, including collagen-binding motifs. We demonstrate that the B. quintana Vomp are multifunctional OMP involved in binding to collagen and autoaggregation: VompC confers the ability to bind collagen IV, and VompA is necessary and sufficient for autoaggregation. The B. quintana Vomp are members of the newly recognized family of YadA-like trimeric autotransporters; the Vomp constitute a multigene family, they are variably expressed, and different virulence properties are attributable to individual Vomp family members.

Survey of three bacterial louse-associated diseases among rural Andean communities in Peru: prevalence of epidemic typhus, trench fever, and relapsing fever

Typhus and other louse-transmitted bacterial infections in Peruvian sierra communities are known to occur but have not recently been assessed. In this study, 194 of 1,280 inhabitants of four villages in Calca Province in the Urubamba Valley were included. Thirty-nine (20%) of the 194 volunteers had antibodies to Rickettsia prowazekii, whereas 24 (12%) had antibodies to Bartonella quintana and 2 against Borrelia recurrentis. There was a significant correlation between the presence of infesting ectoparasites and antibodies to R. prowazekii, as well as between antibodies to R. prowazekii and ectoparasite infestation and fever in the previous 6 months. The proportion of inhabitants infested with ectoparasites was significantly higher in the highest-altitude village than in the other three villages. Two volunteers' antibody levels suggested a recent typhus infection, but only B. quintana DNA was amplified from lice. Epidemic typhus remains extant in the area, and B. quintana infections were encountered and documented for the first time in South America.