Native valve endocarditis due to Bartonella henselae in an immunocompetent man

Culture-negative endocarditis accounts for 2.5-31% of all endocarditis cases and remains a diagnostic and therapeutic challenge. Bartonella spp. has only recently been recognized as an important cause of culture-negative endocarditis. We report a case of Bartonella henselae endocarditis occurring in an immunocompetent man who owned a cat and had previously been diagnosed with valvulopathy. Diagnosis was made only after prolonged diagnostic work-up with serology and with PCR and subsequent sequencing to identify the microorganism in the excised valves. The duration of treatment in patients with bartonella endocarditis is not clearly defined, and we decided to treat our patient with a prolonged course of antibiotic. Surgical treatment is usually necessary and was also successful in our patient. To our knowledge, this is the first case of bartonella endocarditis occurring in our geographic area.     

A view on Bartonella quintana endocarditis--confirming the molecular diagnosis by specific fluorescence in situ hybridization

Culture-negative endocarditis is a frequent problem in cardiology, especially if caused by fastidious organisms. Among these, the diagnostic tools for the detection of Bartonella quintana are still unsatisfactory. In a culture-negative case of suspected endocarditis undergoing aortic valve replacement, polymerase chain reaction amplification and sequencing of the 16S rRNA gene indicated B. quintana infection. To develop a new diagnostic tool, independent from culture and amplification techniques, we designed and optimized an oligonucleotide fluorescence in situ hybridization (FISH) probe specific for B. quintana and suitable for FISH. FISH succeeded in simultaneous visualization and identification of vital microorganisms directly within the aortic valve tissue and in fast and univocal diagnosis of B. quintana endocarditis.     

Prosthetic valve endocarditis caused by Bartonella quintana in a patient during immunosuppressive therapies for collagen vascular diseases

Bartonella quintana, known to cause various clinical symptoms, is increasingly recognized as one important cause of culture-negative endocarditis. We report a case of infectious endocarditis with B. quintana on the prosthetic valve, accompanied by proteinase 3-antineutrophil cytoplasmic antibody-positive collagen vascular disease-like symptoms 1 year earlier.     

Laboratory diagnosis of Bartonella infections

Bartonella species are pathogens of emerging and reemerging significance, causing a wide array of clinical syndromes. In North America and Europe, they are increasingly recognized as a cause of culture negative endocarditis, neuroretinitis, and disease among homeless, HIV-infected, and other immunosuppressed individuals. In South America, bartonellosis continues to plague those in endemic regions and poses a significant threat to travelers in these areas. As the clinician is increasingly faced with these illnesses, which may be difficult to diagnose, laboratory techniques to confirm or refute the diagnosis are becoming increasingly important. Culture methods have improved over the past decade demonstrating increased sensitivity, but still require prolonged periods before isolation of the organism. Specimen handling, media selection, and growth conditions all may affect results and must be optimized in order to provide the highest likelihood of recovering the organism. Pure culture of the bacteria not only provides morphologic information, but also provides material for further diagnostic testing. Work with liquid media, which may provide a more rapid means of cultivation has shown some promise and should continue to be pursued. Improved blood culture techniques were a primary factor in the discovery of Bartonella endocarditis and continued improvements will likely demonstrate further clinical insights. Serologic testing for B henselae infections has become the cornerstone of clinical diagnosis, replacing the skin test that was poorly standardized and posed a potential risk to the patient. Immunofluorescence assays have been well characterized and validated in clinical trials, however they are not universally available. Vero cell cocultivated antigens appear to provide higher sensitivity and specificity when compared with agar-derived antigens. IFA assays are inherently difficult to perform, requiring significant expertise to provide reproducible results. On the contrary, enzyme immunoassays offer ease of use and a high level of reproducibility, however ideal antigens for use in the diagnosis of Bartonella infections have not been clearly identified. Continued work to define antigenic targets of the human response to infection and incorporation of these into a widely available EIA will provide a cost-effective tool for the clinician and epidemiologist alike. Due to the close phylogenetic relationship of B henselae and B quintana, differentiation between these species by serologic means may prove difficult. Molecular techniques including PCR offer high sensitivity and specificity, rapid availability of information, and the ability to differentiate Bartonella organisms at the highest level. Results of studies to date are promising and as methods are refined it will be important to conduct clinical studies to define the role of these assays. In disseminated Bartonella infections such as bacillary angiomatosis, peliosis, endocarditis, and urban trench fever, PCR currently offers the ability to establish the diagnosis when other tests may be unrevealing. For CSD, this technique should be used as a confirmatory technique when the diagnosis is unclear by other means. PCR analysis of blood specimens offers a minimally invasive approach to diagnosis, but clinical data are scarce and further studies are needed. As DNA microarrays move into the clinical arena, specific hybridization probes may allow improved identification and differentiation of Bartonellae at the molecular level.     

A first Japanese case of Bartonella henselae-induced endocarditis diagnosed by prolonged culture of a specimen from the excised valve

Bartonella henselae, the causative agent of cat scratch disease, is increasingly recognized as a cause of culture-negative endocarditis. This report describes the first Japanese case, which was diagnosed after a prolonged culture of the excised aortic valve. High IgG and IgM titers to B. henselae pointed to a subacute course of the disease.     

An unusual outcome in a child with hepatosplenic cat-scratch disease

Typical cat-scratch disease (Bartonella henselae infection) in an immunocompetent child is usually associated with a history of scratch, bite or intimate contact with a cat. Most patients develop a non-tender papule in the scratch line after three to ten days. This may persist for only a few days or as long as two to three weeks. During the next two weeks or more, regional lymph nodes that drain the area gradually enlarge and then slowly resolve in more than 10% of patients. The nodes develop overlying erythema and may suppurate. Atypical forms of cat-scratch disease occur in a minority of cases and are characterized by ocular or neurological manifestations, hepatosplenic involvement, vertebral osteomyelitis, endocarditis etc. Immunocompromised individuals with B. henselae infection may develop bacillary angiomatosis, bacillary peliosis, and relapsing bacteremia. There have been several reports of hepatosplenic granulomas caused by B. henselae in immunocompetent children. We report a case of a 6-year-old boy with the hepatosplenic form of cat-scratch disease. Despite early diagnosis and long-term antimicrobial treatment, splenectomy could not be avoided.     

In situ detection of Bartonella henselae cells

A new in situ hybridization technique was developed for identification of Bartonella henselae cells in cell suspension or in tissue sections. Use of highly specific probes labeled with either fluorescein or digoxigenin allows discrimination between B. henselae and closely related B. quintana cells. No cross-hybridization with other Bartonella or non-Bartonella species was observed. Besides its specificity it showed higher sensitivity as compared to PCR based detection methods. Moreover, its application allows direct observation of B. henselae in infected tissues.     

新疆古尔图地区长尾黄鼠感染病原体情况调查

目的调查新疆维吾尔自治区（新疆）古尔图地区长尾黄鼠汉赛巴尔通体、伯氏疏螺旋体和嗜吞噬细胞无形体等病原体感染情况,分析该地区自然疫源性疾病流行风险,为制定防控措施提供科学依据。方法2017年5 — 9月采用一日弓形夹法捕捉查岗果勒、布兰布拉克、白石头等地长尾黄鼠86只,无菌采集鼠体肾脏,试剂盒法提取全基因组DNA;运用实时荧光定量聚合酶链式反应方法检测样本汉赛巴尔通体ssrA基因、伯氏疏螺旋体recA基因和嗜吞噬细胞无形体Msp2基因。结果共检测86只长尾黄鼠样本,其中汉赛巴尔通体阳性42份,阳性率为48.84%;伯氏疏螺旋体阳性6份,阳性率为6.98%;嗜吞噬细胞无形体阳性3份,阳性率为3.49%。 布兰布拉克地区的汉赛巴尔通体感染率高于查岗果勒和白石头地区,白石头地区的伯氏疏螺旋体和嗜吞噬无形体感染率高于其他两地。结论新疆古尔图地区长尾黄鼠存在汉赛巴尔通体、伯氏疏螺旋体和嗜吞噬细胞无形体感染。     

Molecular diagnosis of Coxiella burnetii in culture negative endocarditis and vascular infection in South Korea

BackgroundQ fever endocarditis is a major cause of culture-negative endocarditis. The role of Coxellia burnetii is underestimated because it is difficult to diagnose. We investigated the significance of C. burnetii as the cause of culture-negative endocarditis and vascular infection by examining blood and tissue specimens using serological testing and polymerase chain reaction (PCR).MethodsAll patients with infective endocarditis or large vessel vasculitis were prospectively enrolled at a tertiary-care hospital from May 2016 through September 2020. Q fever endocarditis and vascular infection were diagnosed based on: (1) positive PCR for a cardiac valve or vascular tissue, (2) positive PCR for blood or phase I immunoglobulin G (IgG) ≥ 6400, or (3) phase I IgG ≥ 800 and < 6400 with morphologic abnormality. PCR targeted C. burnetii transposase gene insertion element IS1111a.ResultsOf the 163 patients, 40 (25%) had culture-negative endocarditis (n = 35) or vascular infection (n = 5). Of the 40 patients, 24 (60%) were enrolled. Eight (33%) were diagnosed with Q fever endocarditis or vascular infection. Of these 8 patients, 6 had suspected acute Q fever endocarditis or vascular infection with negative phase I IgG. Six patients were not treated for C. burnetii, 4 were stable after surgery. One patient died due to surgical site infection after 5 months post-operatively and one died due to worsening underlying disease.ConclusionsApproximately one-third of patients with culture-negative endocarditis and vascular infection was diagnosed as Q fever. Q fever endocarditis and vascular infection may be underestimated in routine clinical practice in South Korea.

KEY MESSAGE

• Q fever endocarditis and vascular infection may be underestimated in routine clinical practice, thus, try to find evidence of C. burnetti infection in suspected patients by all available diagnostic tests including PCR.

     

Unusual concurrent detection by polymerase chain reaction of Bartonella henselae and parvovirus b19 in an immunocompetent child with erythema nodosum and hepatic granulomatous disease

We report an unusual case of documented Bartonella henselae genotype I from hepatic tissue in an Italian immunocompetent girl presenting with erythema nodosum and hepatic granulomata. Polymerase chain reaction (PCR) was performed on biopsied liver sample to confirm the etiologic role of B. henselae and to identify the genetic variant of this organism. A PCR on the same liver biopsy for parvovirus B19 was also positive, but the clinical meaning of this was not clear.     

Discovery and analysis of Bartonella henselae antigens for use in clinical serologic assays

The antibody response to Bartonella henselae has been studied in a number of mammals; however, the human response needs to be further studied. After natural infection, humans have antibody reactivity to a large number of B. henselae proteins. We used a proteomic approach to identify antigenic proteins of B. henselae to determine their capacity to elicit a human antibody response. Comparing patient sera by Western blot analysis demonstrated significant amounts of reactivity to B. henselae. The immunofluorescence assay (IFA)-positive sera identified several protein spots of interest. However, a consistent reactivity to a single spot by all sera was not observed. Three of these spots demonstrated reactivity in 71%, 64%, and 64% of positive sera tested with negligible reactivity to the negative sera. These proteins were identified as GroES, BepA, and GroEL. Most IFA-positive sera demonstrated reactivity to GroES, GroEL, and BepA. The usefulness of these proteins for a clinical serologic assay is discussed.     

Bartonella henselae survives after the storage period of red blood cell units: is it transmissible by transfusion?

Bartonella henselae is the agent of cat scratch disease and bacillary angiomatosis. Blood donors can be asymptomatic carriers of B. henselae and the risk for transmission by transfusion should be considered. The objective of this study was to demonstrate that B. henselae remains viable in red blood cell (RBC) units at the end of the storage period. Two RBC units were split into two portions. One portion was inoculated with B. henselae and the other was used as a control. All units were stored at 4 degrees C for 35 days. Aliquots were collected on a weekly basis for culture in a dish with chocolate agar, ideal for the cultivation of this agent. Samples were collected on days 1 and 35 and taken for culture in Bact/Alert R blood culture bottles. Aliquots taken simultaneously were fixed in Karnovsky's medium for subsequent electron microscopy evaluation. Samples from infected bags successfully isolated B. henselae by chocolate agar culture, although Bact/Alert R blood culture bottles remained negative. Bartonella spp. structures within erythrocytes were confirmed by electron microscopy. The viability of B. henselae was demonstrated after a storage period of RBC units. These data reinforce the possibility of infection by transfusion of blood units collected from asymptomatic blood donors.     

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.     

Molecular diagnosis of microbial aetiologies using SepsiTest™ in the daily routine of a diagnostic laboratory

A universal PCR and sequencing test, SepsiTest™ (Molzym, Germany) was evaluated for its applicability during daily diagnostic routine in a privately operated laboratory. In total, 96 specimens originating from 66 patients under suspect of infectious endocarditis, infections of joints, encephalitis/meningitis, systemic infections and infections of unknown genesis were PCR analysed and compared to culture results. Samples comprised cultured and non-cultured blood, synovial fluid, synovial tissue, heart valves, pacemakers, spinal tissue, cerebrospinal fluid, and swabs. PCR and culture were concordant in 26 negative and 8 positive cases (51.5%). A group of 25 patients was culture-negative but PCR-positive (37.9%). In at least 14 of these, common and/or rare aetiologies were identified, while for 4 patients the results of 16S PCR could not be unequivocally linked with the underlying disease. Benefits and limitations of the molecular test are discussed with special emphasis on technical and economic issues. In conclusion, SepsiTest™ proved to be a valuable tool for the diagnosis of aetiologies, particularly in cases of culture-negative patients who are under strong suspicion for an infection.     

Parotid mass due to cat scratch disease

Cat scratch disease (CSD), due to Bartonella henselae, is a self-limited chronic lymphadenopathy. A previously healthy 22-year-old woman presented with a palpable painful swelling in the right submandibular region accompanied by enlarged cervical lymph nodes. A diagnosis of B. henselae infection was made according to her personal history that divulged frequent contacts with cats and to a high titre of immunoglobulin G (IgG) and IgM antibodies for this agent. The patient improved within 1 month without the requirement of antibiotic treatment or surgery. The CSD should always be included in the differential diagnosis of all equivocal masses in the neck, especially in young individuals. In addition, it is important that a meticulous personal history is obtained.     

Production of recombinant Bartonella henselae 17-kDa protein for antibody-capture enzyme-linked immunosorbent assay

The Bartonella henselae 17-kDa protein was expressed in a prokaryotic expression system as a histidine-tagged fusion protein and was purified. The target gene was cloned into a recombinant expression construct, pTri-17kd. The expressed protein was purified to near homogeneity by a nickel-agarose column chromatography. Protein recovery was estimated to be 2.9 mg from 100 mL of bacterial culture. The purified 17-kDa protein was recognized by serum from patients infected with B. henselae and Bartonella quintana, suggesting antigenic integrity. The sensitivity and specificity of the IgG enzyme-linked immunosorbent assay (ELISA) relative to immunofluorescent antibody assay testing were 71.1% and 93.0%, respectively. According to the receiver operating characteristic curve analysis, the area under the curve was 0.823. These results indicate that the expressed 17-kDa protein is a suitable source of antigen for development of an antibody-capture ELISA for the detection of antibodies to B. henselae.     

Bacteriological outcome of combination versus single-agent treatment for staphylococcal endocarditis

OBJECTIVE: To analyse the bacteriological outcome of combination versus single-agent antimicrobial treatment in staphylococcal endocarditis. PATIENTS AND METHODS: Retrospective review of 152 episodes: 91 cases of native valve endocarditis (NVE), 74 due to Staphylococcus aureus and 17 due to coagulase-negative staphylococci (CoNS); and 61 cases of prosthetic valve endocarditis (PVE), 29 due to S. aureus and 32 due to CoNS. RESULTS: Valves from patients with S. aureus NVE treated with any kind of combination antibiotic treatment were no more likely to be culture-negative than those treated with a single agent [19 (45%) of 42 versus 13 (41%) of 32; P = 0.69]. This finding remained unchanged when cases of CoNS NVE were added to the S. aureus group. In PVE, after adjusting for duration of treatment, valves from patients receiving any kind of combination treatment were 5.9 times (95% confidence interval 1.3-27.5) more likely to be culture-negative than those receiving monotherapy (P = 0.024). Patients treated for >14 days were more likely to be culture-negative than those treated for 相似文献   

Cat-scratch Disease

Cat-scratch disease is a common infection that usually presents as tender lymphadenopathy. It should be included in the differential diagnosis of fever of unknown origin and any lymphadenopathy syndrome. Asymptomatic, bacteremic cats with Bartonella henselae in their saliva serve as vectors by biting and clawing the skin. Cat fleas are responsible for horizontal transmission of the disease from cat to cat, and on occasion, arthropod vectors (fleas or ticks) may transmit the disease to humans. Cat-scratch disease is commonly diagnosed in children, but adults can present with it as well. The causative microorganism, B. henselae, is difficult to culture. Diagnosis is most often arrived at by obtaining a history of exposure to cats and a serologic test with high titers (greater than 1:256) of immunoglobulin G antibody to B. henselae. Most cases of cat-scratch disease are self-limited and do not require antibiotic treatment. If an antibiotic is chosen, azithromycin has been shown in one small study to speed recovery. Infrequently, cat-scratch disease may present in a more disseminated form with hepatosplenomegaly or meningoencephalitis, or with bacillary angiomatosis in patients with AIDS.     

Rapid identification of Bartonella henselae by real-time polymerase chain reaction in a patient with cat scratch disease

We report a localized submandibular lymph node infection in a patient with cat scratch disease. Directly performing real-time polymerase chain reaction assay on the biopsy sample, Bartonella henselae DNA was simultaneously detected and identified.