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Bartonella henselae: etiology of pulmonary nodules in a patient with depressed cell-mediated immunity.

We describe an immunocompromised renal transplantation patient with opportunistic lung infection due to Bartonella henselae (formerly Rochalimaea henselae) and provide evidence suggesting transmission from a pet cat. Computed tomographic scans of the chest and lung biopsies provided material for diagnosis. The etiology was established by polymerase chain reaction and sequencing of a 16S ribosomal DNA segment from infected lung tissue. Histopathologic and serological evidence supported the molecular data. B. henselae was isolated from the blood of eight of the patient's many cats. The patient responded to prolonged therapy with doxycycline, and relapse did not occur during a 1-year follow-up. B. henselae joins a long list of pathogens that can cause lung infections in association with cell-mediated immunodeficiency states. Molecular methods are useful in diagnosis of this infection in light of the bacterium's fastidious growth characteristics. If an immunocompromised patient has lung nodules and a history of exposure to cats, B. henselae should be sought in biopsy specimens.

Adult↗

Necrotizing glomerulonephritis caused by Bartonella henselae endocarditis.

Glomerulonephritis secondary to endocarditis is uncommon and usually associated with valvular infection by blood culture-positive bacteria. We report 3 cases of necrotizing glomerulonephritis associated with culture-negative endocarditis caused by Bartonella henselae. Two of the patients presented with renal abnormalities and were investigated for endocarditis after results of renal biopsy. All 3 patients had an immune complex-mediated necrotizing and crescentic glomerulonephritis with mesangial and capillary wall deposition of immunoglobulin M (IgM), IgG, and C3. Electron microscopy showed immune-type electron-dense deposits in the mesangium and segmental subendothelial (2 cases) or subepithelial (1 case) deposits. Patients were treated with antibiotics, including azithromycin or doxycycline and ceftriaxone or tobramycin. In addition, 2 patients were administered steroids and 2 patients underwent valve replacement surgery. The 2 patients who underwent cardiac surgery were discharged from the hospital with stable renal function. The third patient died 4 months after hospital admission of renal failure. In conclusion, glomerulonephritis caused by B henselae endocarditis is an immune complex-mediated disease characterized by segmental necrotizing and crescentic glomerular lesions that can respond to aggressive medical and surgical therapy.

Adult↗

Clinical, histologic, microbiologic, and biochemical characterization of the causative agent of bacillary (epithelioid) angiomatosis: a rickettsial illness with features of bartonellosis.

It has been suggested that bacillary (epithelioid) angiomatosis (BEA) is a manifestation of cat scratch disease (CSD). Because of clinical similarity between this condition and the verruga peruana phase of bartonellosis, we sought to further characterize this disease as well as its causative agent and to compare it to bartonellosis. We isolated a small flagellated pleomorphic bacillus from skin lesions of two patients with BEA. Organisms were stained successfully with Warthin-Starry silver stains, but immunohistochemistry failed to demonstrate binding with a polyclonal antibody directed against the cat scratch bacillus. Whole cell fatty-acid gas chromatography performed on both BEA organisms and Bartonella bacilliformis demonstrated marked similarity between the two. Electron microscopy of BEA organisms in tissue and in suspension revealed features characteristic of a gram negative bacillus. Based on these findings, we propose that this unusual rickettsial infectious disease with vascular proliferation may represent an unusual variant of infection with a bartonella-like organism rather than a manifestation of cat scratch disease.

Adult↗

[Bartonella endocarditis on native valves. Apropos of 2 cases].

The authors report two cases of Bartonella endocarditis in native valves. The first case was a 15 year old North African Girl who lived in poor social conditions and was admitted to hospital with pyrexia and congestive heart failure. Investigations revealed massive mitral regurgitation due to ruptured chordae tendinae, vegetations on the pulmonary valve with severe pulmonary hypertension due to persistent ductus arteriosus. After antibiotic therapy, the patient underwent surgery for mitral valve replacement, pulmonary valvuloplasty and closure of the patent ductus arteriosus. The second case was a 39 year old man with no fixed abode with a history of alcoholism who presented with a recurrent ischaemic stroke in a context of infection with a murmur of aortic regurgitation. Echocardiography showed a vegetation on the aortic valve with grade III/IV regurgitation requiring aortic valve replacement with a homograft after antibiotic therapy. The aetiological diagnosis was made a posteriori by the finding of high antibody titres and specific genetic amplification of Bartonella. In patients with negative blood cultures, Bartonella infection should be looked for systematically especially in those living under poor social conditions. The practical diagnostic investigation of endocarditis with negative blood cultures is reviewed.

Adolescent↗

IgM to Bartonella henselae in cat-scratch disease and during acute Epstein-Barr virus infection.

The diagnostic value of IgM to Bartonella henselae was evaluated in 20 children with cat-scratch disease (CSD) and controls consisting of 20 blood donors and 20 children with enlarged lymph nodes without CSD by two indirect immunofluorescence assays (IFA). One was based on B. henselae cocultivated with Vero cells (host cell-associated IFA), and the other on B. henselae grown on agar (host cell-free IFA). With the host cell-associated IFA, 18 of 20 children with CSD revealed IgM, whereas only 14 did so with the host cell-free IFA. Sera of two blood donors as well as sera from three children with enlarged lymph nodes without CSD showed also positive IgM to cell-associated B. henselae. This study reveals that the IFA applied had sensitivities of 70-90% and specificities of 87.5-100% for detecting IgM to B. henselae. Additionally, 20 patients with IgM to Epstein-Barr virus (EBV) capsid antigen were tested for IgM to B. henselae. Sera of 16 and 9 of these patients revealed IgM to B. henselae with the host cell-associated and the host cell-free IFA, respectively. Using Western blot these sera were demonstrated to react against linearized proteins of Vero cells and of B. henselae. Thus, since acute EBV infection may substantially reduce the specificity of B. henselae-specific IgM tests, we conclude that diagnosis of CSD should be confirmed by a significant IgG titer to B. henselae or by detection of this pathogen.

Animals↗

Prevalence of Bartonella species, haemoplasma species, Ehrlichia species, Anaplasma phagocytophilum, and Neorickettsia risticii DNA in the blood of cats and their fleas in the United States.

Ctenocephalides felis were killed and collected from 92 cats in Alabama, Maryland, and Texas. The fleas and blood from the corresponding cat were digested and assessed in polymerase chain reaction assays that amplify DNA of Ehrlichia species, Anaplasma phagocytophilum, Neorickettsia risticii, Mycoplasma haemofelis, 'Candidatus M haemominutum' and Bartonella species. DNA consistent with B henselae, B clarridgeiae, M haemofelis, or 'Candidatus M haemominutum' was commonly amplified from cats (60.9%) and their fleas (65.2%). Results of this study support the recommendation to maintain flea control on cats in endemic areas.

Alabama↗

Infection of fetal feline brain cells in culture with Bartonella henselae.

Bartonella henselae is known to cause central nervous system (CNS) disease in humans, and neurological signs have been observed in experimentally infected cats. However, the pathogenesis of CNS disease remains unclear. This study was undertaken to determine whether B. henselae infects feline fetal brain cells in vitro. Microglial-cell- and astrocyte-enriched cultures were inoculated with B. henselae. Giménez staining identified bacterial organisms within microglial cells by day 7 postinoculation. The viability of the intracellular bacteria was demonstrated by incubating cultures with gentamicin and plating cell lysate on agar. Electron microscopy identified intracellular organisms with characteristic Bartonella morphology but identified no ultrastructural abnormalities within infected microglial cells. No evidence of infection was seen in Bartonella-inoculated astrocyte cultures. These findings suggest a role for microglia in the pathogenesis of B. henselae-associated neurological disease.

Animals↗

Sequential evaluation of dogs naturally infected with Ehrlichia canis, Ehrlichia chaffeensis, Ehrlichia equi, Ehrlichia ewingii, or Bartonella vinsonii.

Historically, disease manifestations in dogs seroreactive to Ehrlichia canis antigens by indirect immunofluorescent antibody testing have been attributed to infection with either E. canis or Ehrlichia ewingii. A 1996 study by Dawson and colleagues provided PCR evidence that healthy dogs from southeastern Virginia could be naturally infected with Ehrlichia chaffeensis. This observation stimulated us to determine which Ehrlichia spp. infected sick dogs that were referred to our hospital from the same region. Based upon PCR amplification with species-specific primers, sick dogs seroreactive to E. canis antigens were determined to be infected with four Ehrlichia species: E. canis, E. chaffeensis, E. equi, and E. ewingii. Coinfection with three Ehrlichia species (E. canis, E. ewingii, and E. equi) was documented for one dog. An additional canine pathogen presumed to be tick transmitted, Bartonella vinsonii subsp. berkhoffii, was identified in 7 of 12 dogs. Importantly, our results indicate that in naturally infected dogs, E. chaffeensis can cause severe disease manifestations that are clinically and serologically indistinguishable from disease manifestations of E. canis or E. ewingii. In addition, our findings support the efficacy of doxycycline for treatment of E. canis, E. equi, and E. ewingii infections but indicate that, based upon the persistence of E. chaffeensis DNA for 1 year following treatment, E. chaffeensis infection in dogs may be more refractory to doxycycline treatment. Undetected coinfection with Bartonella may also complicate the evaluation of treatment efficacy while resulting in disease manifestations that mimic ehrlichiosis.

Animals↗

Experimental infection of young specific pathogen-free cats with Bartonella henselae.

Eighteen 12-week-old specific pathogen-free cats, blood culture- and serum antibody-negative for Bartonella henselae, were randomly allocated to groups and were intravenously inoculated with 10(10) (group 1), 10(8) (group 2), or 10(6) (group 3) B. henselae or with saline (group 4) or were not inoculated (group 5). Cats were humanely killed at 2, 4, 8, 16, and 32 weeks after inoculation. All B. henselae-inoculated cats were bacteremic by 2 weeks after infection. Bacteremia persisted until 32 weeks after infection in 1 cat. Cats in groups 1 and 2 had fever (>39.7 degrees C) and partial anorexia by 2 weeks after infection that lasted 2-7 days. All infected cats had Bartonella-specific IgM and IgG serum antibodies and lymphocyte blastogenic responses. Histopathologic lesions were observed in multiple organs of infected cats through 8 weeks after infection. Cats were readily infected with B. henselae by intravenous inoculation, developed histopathologic lesions that apparently resolved, and developed B and T lymphocyte responses to infection.

Animals↗

Use of rpoB gene analysis for detection and identification of Bartonella species.

Identification of Bartonella species is of increasing importance as the number of infections in which these bacteria are involved increases. To date, these gram-negative bacilli have been identified by various serological, biochemical, and genotypic methods. However, the development of alternative tools is required, principally to circumvent a major risk of contamination during sample manipulation. The aim of our study was to investigate the possible identification of various Bartonella species by comparison of RNA polymerase beta-subunit gene (rpoB) sequences. This approach has previously been shown to be useful for the identification of members of the family Enterobacteriaceae (C. M. Mollet, M. Drancourt, and D. Raoult, Mol. Microbiol. 26:1005-1011, 1997). Following PCR amplification with specific oligonucleotides, a 825-bp region of the rpoB gene was sequenced from 13 distinct Bartonella strains. Analysis of these sequences allowed selection of three restriction enzymes (ApoI, AluI, and AflIII) useful for discerning the different strains by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis. To confirm the potential value of such an approach for identification of Bartonella, the rpoB PCR was then applied to 94 clinical samples, and the results obtained were identical to those obtained by our reference PCR method. Twenty-four isolates were also adequately identified by PCR-RFLP analysis. In all cases, our results were in accordance with those of the reference method. Moreover, conserved regions of DNA were chosen as suitable primer targets for PCR amplification of a 439-bp fragment which can be easily sequenced.

Animals↗

Recent progress in understanding Bartonella-induced vascular proliferation.

The ability to induce endothelial cell proliferation is a common feature of human pathogenic Bartonella species. Recent data have indicated that bartonellae can provoke angioproliferation by at least two independent mechanisms: directly, by triggering proliferation and inhibiting apoptosis of endothelial cells; and indirectly, by stimulating a paracrine angiogenic loop of vascular endothelial growth factor production by infected macrophages. A NF-kappaB-mediated acute inflammatory reaction of the Bartonella-infected endothelium appears to be critical for the recruitment of monocytes/macrophages and the initiation and maintenance of a paracrine angiogenic loop. Given that bartonellae effectively adhere to and invade endothelial cells, their ability to trigger angioproliferation might represent a dedicated pathogenic strategy for expanding the bacterial host cell habitat.

Apoptosis↗

[Detection of Bartonella (Rochalimaea) henselae/B. quintana by polymerase chain reaction (PCR)].

Bartonella (Rochalimaea) henselae and/or B. quintana are the causative agents of a variety of infections such as trench fever, bacillary angiomatosis, septicemia, peliosis hepatis and endocarditis. Recently, B. henselae has been identified as a major cause of cat scratch disease. Diagnosis of such infections is based on clinical information, histopathology, culture and serology. However, none of these methods alone is sufficiently sensitive or specific. We have used the PCR to search for DNA specific for B. henselae/B. quintana in 33 clinical samples and in 6 controls. In comparison with clinical data and histopathology, PCR was extremely specific (100%) and reasonably sensitive (61%). Possible explanations for the limited sensitivity of PCR are discussed. We conclude that PCR provides a useful adjunct for the diagnosis of infections caused by B. henselae and B. quintana.

Bartonella Infections↗

Giant hepatic granuloma caused by Bartonella henselae.

We report a 10-year-old girl with a 3.0- by 3.5-cm giant hepatic granuloma caused by Bartonella henselae. Such a solitary and large granuloma associated with B. henselae infection has not been previously reported. We believe that B. henselae infection is a consideration in the differential diagnosis of a large hepatic mass.

Bartonella Infections↗

Bartonella adhesin a mediates a proangiogenic host cell response.

Bartonella henselae causes vasculoproliferative disorders in humans. We identified a nonfimbrial adhesin of B. henselae designated as Bartonella adhesin A (BadA). BadA is a 340-kD outer membrane protein encoded by the 9.3-kb badA gene. It has a modular structure and contains domains homologous to the Yersinia enterocolitica nonfimbrial adhesin (Yersinia adhesin A). Expression of BadA was restored in a BadA-deficient transposon mutant by complementation in trans. BadA mediates the binding of B. henselae to extracellular matrix proteins and to endothelial cells, possibly via beta1 integrins, but prevents phagocytosis. Expression of BadA is crucial for activation of hypoxia-inducible factor 1 in host cells by B. henselae and secretion of proangiogenic cytokines (e.g., vascular endothelial growth factor). BadA is immunodominant in B. henselae-infected patients and rodents, indicating that it is expressed during Bartonella infections. Our results suggest that BadA, the largest characterized bacterial protein thus far, is a major pathogenicity factor of B. henselae with a potential role in the induction of vasculoproliferative disorders.

Adhesins, Bacterial↗

Invasion and persistent intracellular colonization of erythrocytes. A unique parasitic strategy of the emerging pathogen Bartonella.

The expanding genus Bartonella includes zoonotic and human-specific pathogens that can cause a wide range of clinical manifestations. A productive infection allowing bacterial transmission by blood-sucking arthropods is marked by an intraerythrocytic bacteremia that occurs exclusively in specific human or animal reservoir hosts. Incidental human infection by animal-adapted bartonellae can cause disease without evidence for erythrocyte parasitism. A better understanding of the intraerythrocytic lifestyle of bartonellae may permit the design of strategies to control the reservoir and transmittable stages of these emerging pathogens. We have dissected the process of Bartonella erythrocyte parasitism in experimentally infected animals using a novel approach for tracking blood infections based on flow cytometric quantification of green fluorescent protein-expressing bacteria during their interaction with in vivo-biotinylated erythrocytes. Bacteremia onset occurs several days after inoculation by a synchronous wave of bacterial invasion into mature erythrocytes. Intracellular bacteria replicate until reaching a stagnant number, which is sustained for the remaining life span of the infected erythrocyte. The initial wave of erythrocyte infection is followed by reinfection waves occurring at intervals of several days. Our findings unravel a unique bacterial persistence strategy adapted to a nonhemolytic intracellular colonization of erythrocytes that preserves the pathogen for efficient transmission by blood-sucking arthropods.

Animals↗

Population genetic analysis of Bartonella bacilliformis isolates from areas of peru where Carrion's disease is endemic and epidemic.

Carrion's disease is caused by infection with the alpha-proteobacterium Bartonella bacilliformis. Distribution of the disease is considered coincident with the distribution of its known vector, the sand fly Lutzomyia verrucarum. Recent epidemics of B. bacilliformis infections associated with atypical symptomatology in nonendemic regions have raised questions regarding the historic and present distribution of this bacterium and the scope of disease that infection causes. Phylogenetic relationships and genomic diversity of 18 B. bacilliformis isolates (10 isolates from a region where Carrion's disease is epidemic, Cuzco, Peru, and 8 isolates from a region where Carrion's disease is endemic, Caraz, Peru) were assessed using genomic data generated by infrequent restriction site PCR and gene sequence analysis of the flagellin gltA and ialB genes. A population genetic analysis of the genomic diversity suggests that what was once considered an epidemic region of Peru did not result from the recent introduction of B. bacilliformis.

Bartonella Infections↗