High prevalence of Bartonella henselae and Bartonella quintana antibodies in Croatian patients presenting with lymphadenopathy.

Between 2007 and 2010, a total of 268 Croatian patients with lymphadenopathy were tested for IgM/IgG antibodies to Bartonella (B.) henselae and B. quintana. Samples from 44.4% patients showed positive IgG antibodies: 35.8% to B. henselae, 6.7% to B. quintana and 1.9% to both Bartonella species. There was no difference in seropositivity between males and females (47.4% vs. 41.5%). Seroprevalence was high in all age groups (40.4-60.9%). Patients from urban and rural areas showed a similar seroprevalence rate (44.1% vs. 44.8%). Positive IgM antibodies were found in 28.3% patients varying from 17.5% and 37.5% among age groups. Most cases were reported from August to March.

The Janus face of Bartonella quintana recognition by Toll-like receptors (TLRs): a review.

Bartonella quintana (B. quintana) is a facultative, intracellular bacterium, which causes trench fever, chronic bacteraemia and bacillary angiomatosis. Little is known about the recognition of B. quintana by the innate immune system. In this review, we address the impact of Toll-like receptors (TLRs) on the recognition of B. quintana and the activation of the host defense. When experimental models using human mononuclear cells, transfected CHO cells, or TLR2-/- and TLR4-/- mice were used, differential effects of TLR2 and TLR4 have been observed. B. quintana micro-organisms stimulated cytokine production through TLR2-mediated signals, whereas no role for TLR4 in the recognition of this pathogen was observed. When single, water-phenol extraction was performed, B. quintana LPS, stimulated cytokine production in a TLR2-dependent manner. However, when double extraction was performed in order to generate highly purified LPS, B. quintana LPS entirely lost its capacity to stimulate cytokines, demonstrating that non-LPS components of B. quintana are responsible for the recognition through TLR2. Moreover, B. quintana LPS was shown to be a potent antagonist of Toll-like receptor 4 (TLR4). In conclusion, B. quintana is an inducer of cytokines through TLR2-, but not TLR4-, dependent mechanisms. This stimulation is induced by bacterial components other than lipopolysaccharide. B. quintana LPS is a naturally occurring antagonist of Toll-like receptor 4 (TLR4). In view of the role played by TLR4 in inflammation, B. quintana LPS may be useful as an anti-TLR4 agent with therapeutic potential in both infections and autoimmune inflammation.

Occurrence of Bartonella henselae and Bartonella quintana among human immunodeficiency virus-infected patients.

The purpose of this study was to determine the seroprevalence against Bartonella henselae and Bartonella quintana among a risk group, patients with HIV infection, and to identify the epidemiological factors involved. Our data indicate that the prevalence of Bartonella infection among HIV-infected patients is much greater than that in the healthy population of the same area and that Bartonella infection should be considered in the differential diagnosis for patients with HIV disease.

In vitro Bartonella quintana infection modulates the programmed cell death and inflammatory reaction of endothelial cells.

Bartonella quintana is an epicellular bacterium, which in vivo as well as in vitro, invades endothelial cells and develops within them inducing proliferative effects that play a pivotal role in neovascular manifestation of this disease. We investigated the effect of live Bartonella quintana and its LPS on apoptosis and inflammatory response in HUVEC-C, an endothelial cell line. The kinetics of the programmed cell death of Bartonella quintana-infected HUVEC-C showed a peculiar course. Even if early during infection apoptosis reached a peak after 6 h, later on apoptosis was inhibited. Such apoptosis inhibition was not observed during Bartonella quintana lipopolysaccharide treatment because LPS-stimulated HUVEC-C did progress to cell death. Evaluation of multiple cell signal transduction pathways revealed an overexpression of Apaf 1 and caspase 8 in HUVEC-C after 2 h of infection, and of bcl-2 starting from 10 h post Bartonella quintana infection. Moreover, Bartonella quintana and its LPS showed a different effect on the activation of genes involved in inflammatory response as revealed by molecular analysis of host cells. Bartonella quintana appears to be able to inhibit programmed cell death, inducing intracellular signals leading to survival and proliferation through the bcl-2 gene, despite the early increase of inflammatory status induced in endothelial cells. This mechanism, together with a poor endotoxin ability to stimulate strong inflammatory response, could contribute to the capability of the bacteria to persist intracellularly, causing chronic disease and producing neovascular manifestations.

Bartonella quintana bacteremia and overproduction of interleukin-10: model of bacterial persistence in homeless people.

Chronic asymptomatic bacteremia caused by Bartonella quintana occurs in homeless people, but its pathophysiology is unknown. We investigated homeless people with bacteremia to determine whether the persistence of B. quintana is associated with a specific immune profile. Homeless people without B. quintana infection exhibited an inflammatory profile--levels of circulating markers of leukocyte activation (soluble interleukin [IL]-2 receptor and neopterin) and cytokines released by mononuclear cells (tumor necrosis factor, IL-1beta, IL-6, and IL-10) were significantly higher than levels in healthy control subjects. In contrast, homeless people with B. quintana bacteremia exhibited specific increases in IL-10 secretion by mononuclear cells. This overproduction of IL-10 was associated with an attenuated inflammatory profile. The depressed inflammatory response was specific of bacteremia, because patients with specific antibodies and without bacteremia had responses similar to those of homeless people. The overproduction of IL-10 and attenuated inflammatory response may account for the persistence of B. quintana in homeless people.

Bacillary angiomatosis by Bartonella quintana in an HIV-infected patient.

Bacillary angiomatosis and bacillary peliosis are opportunistic infections caused by Bartonella henselae and Bartonella quintana, which occur in patients with late-stage infection. We report a case of bacillary angiomatosis in an HIV-infected patient with skin, bone, and probably liver involvement, The identification of the agent (B quintana ) was done by polymerase chain reaction in the skin specimen. The patient had complete regression of all lesions after a 6-month regimen of oral erythromycin.

Serological cross-reactions between Bartonella quintana, Bartonella henselae, and Coxiella burnetii.

The clinical manifestations of Q fever and bartonelloses can be confused, especially in cases of infectious endocarditis. Differential diagnosis of the diseases is important because the treatments required for Q fever and bartonelloses are different. Laboratory confirmation of a suspected case of either Q fever or bartonelloses is most commonly made by antibody estimation with an indirect immunofluorescence assay. With an indirect immunofluorescence assay, 258 serum samples from patients with Q fever were tested against Bartonella henselae and Bartonella quintana antigens, and 77 serum samples from patients with infection by Bartonella sp. were tested against Coxiella burnetii antigen. Cross-reactivity was observed: more than 50% of the chronic Q fever patients tested had antibodies which reacted against B. henselae antigen to a significant level. This cross-reaction was confirmed by a cross-adsorption study and protein immunoblotting. However, because the levels of specific antibody titers in cases of Bartonella endocarditis are typically extremely high, low-level cross-reaction between C. burnetii antibodies and B. henselae antigen in cases of Q fever endocarditis should not lead to misdiagnosis, provided serology testing for both agents is performed.

Bartonella (Rochalimaea) quintana causing fever and bacteremia in an immunocompromised patient with non-Hodgkin's lymphoma.

A 48-yr-old man with stage IV non-Hodgkin's lymphoma, became neutropenic following chemotherapy and developed a fever. His blood cultures were processed to enhance the yield of fastidious bacteria. A slow-growing, capnophilic Gram-negative rod was isolated. The febrile episode was treated with cefotaxime, imipenem and vancomycin and resolved. The bacterial isolate was identified as Bartonella (Rochalimaea) quintana by 16S-rDNA gene sequencing. The isolate showed 99.8% sequence homology with the type strain. This is the first isolation of Bartonella (Rochalimaea) quintana from a bacteremic patient in Australia. This bacterium is a fastidious Gram-negative rod requiring prolonged culture for its isolation. Patients with culture-negative pyrexia, especially immunocompromised patients, may need to be investigated for infection with this agent.