In silico identification of drug targets and vaccine candidates against Bartonella quintana: a subtractive proteomics approach.

BACKGROUND: The availability of genes and protein sequences for parasites has provided valuable information for drug target identification and vaccine development. One such parasite is Bartonella quintana, a Gram-negative, intracellular pathogen that causes bartonellosis in mammalian hosts. OBJECTIVE: Despite progress in understanding its pathogenesis, limited knowledge exists about the virulence factors and regulatory mechanisms specific to B. quintana. METHODS AND FINDINGS: To explore these aspects, we have adopted a subtractive proteomics approach to analyse the proteome of B. quintana. By subtractive proteins between the host and parasite proteome, a set of proteins that are likely unique to the parasite but absent in the host were identified. This analysis revealed that out of the 1197 protein sequences of the parasite, 660 proteins are non-homologous to the human host. Further analysis using the Database of Essential Genes predicted 159 essential proteins, with 28 of these being unique to the pathogen and predicted as potential putative targets. Subcellular localisation of the predicted targets revealed 13 cytoplasmic, eight membranes, one periplasmic, and multiple location proteins. The three-dimensional structure and B cell epitopes of the six membrane antigenic protein were predicted. Four B cell epitopes in KdtA and mraY proteins, three in lpxB and BQ09550, whereas the ftsl and yidC proteins were located with eleven and six B cell epitopes, respectively. MAINS CONCLUSIONS: This insight prioritises such proteins as novel putative targets for further investigations on their potential as drug and vaccine candidates.

Unusual subdural empyema in a homeless patient diagnosed by molecular approach: a case report.

BACKGROUND: We report a case of subdural empyema in a homeless patient caused by Bartonella quintana. B. quintana is a facultative intracellular bacteria for which bacterial growth is fastidious. The molecular biology approach has been a real help in establishing the diagnosis. CASE REPORT: A 59-years old homeless patient, with a history of chronic alcohol abuse, was brought to the emergency department with a massive subdural empyema. Extensive microbiological evaluation didn't reveal any pathogen in the pus collected before antibiotic treatment. B. quintana was detected in the pus from the empyema using a 16S rRNA-based PCR. Histology of intraoperative samples was consistent with the diagnosis and a serological assay was positive. The patient responded well to a treatment that included craniectomy with drainage of the loculated pus, total removal of the infected capsule and a combination of antibiotics. CONCLUSION: This unique case of B. quintana-related empyema illustrates the risk of secondary infection of subdural hematoma with B. quintana since such infections have recently reemerged, predominantly among the homeless populations. Patients with subdural empyema in at-risk populations should be systematically evaluated for B. quintana with an appropriate diagnostic approach involving molecular biology.

Blood Culture-Negative Endocarditis, Morocco.

We investigated the microorganisms causing blood culture-negative endocarditis (BCNE) in Morocco. We tested 19 patients with BCNE by serologic methods, molecular methods, or both and identified Bartonella quintana, Staphylococcus aureus, Streptococcus equi, and Streptococcus oralis in 4 patients. These results highlight the role of these zoonotic agents in BCNE in Morocco.

Bartonella quintana and Typhus Group Rickettsiae Exposure among Homeless Persons, Bogotá, Colombia.

In 2015, we investigated Bartonella quintana and typhus group rickettsiae in body lice from homeless persons in Bogotá, Colombia. We found B. quintana-infected body lice and seroprevalence of this microorganism in 19% of homeless persons and typhus group rickettsiae in 56%. Public health professionals should start preemptive measures and active vector control.

[Seroprevalence of Bartonella henselae and Bartonella quintana in blood donors in Aydin province, Turkey]. / Aydin ili kan donörlerinde Bartonella henselae ve Bartonella quintana seroprevalansi

Bartonella species cause several diseases in humans such as cat stratch disease, bacillary angiomatosis, peliosis hepatis, endocarditis, Carrion disease and trench fever. Cat scratch disease and bacillary angiomatosis cases have already been reported in Turkey. Studies from our region, namely Aydin (a province located at Western Anatolia, Turkey) indicated that mean Bartonella henselae IgG seropositivity rate is 11.5% in risk groups and may reach to 26.5% in pet owners. The aim of this study was to determine the seroprevalence of B.henselae and B.quintana in healthy blood donors in our university hospital in Aydin, for estimating the transmission risk via transfusion. The study was designed as a cross-sectional epidemiological study. A total of 333 samples taken from blood donors (49 female, 284 male) who were sequentially admitted to the blood center of the university hospital, in January 2011 were included in the study. All sera were screened in terms of B.henselae and Bartonella quintana IgG antibodies by using two different indirect immunofluorescent antibody (IFA) commercial kits (Vircell, Spain; Focus, USA). Slides were examined at a final magnification of x400 on fluorescent microscope by two different assigned researchers. Fluorescent intensity was graded between 1+ to 4+, and the samples with fluorescence value of ≥ 2+ were considered as positive. The seropositivity rate of IgG antibodies to B.henselae was found as 3.3% (11/333) in blood donors. This rate was 4.1% in female, and 3.2% in male donors, showing no statistically significant difference between the genders (p= 0.668). B.henselae antibody titers were detected as 1/64 in 6 (1.8%), 1/128 in 4 (1.2%) and 1/1024 in 1 (0.3%) patient. All of the B.henselae IgG positive samples also yielded relatively low positivity for B.quintana IgG, possibly indicating cross reactivity. The fluorescence intensity for different kits used was found to be the same in all but one titer. The results reported by two researchers were found to differ only in the samples graded 1+ or below. However, the evaluation differences between the kits and the researchers did not affect the results. It was concluded that B.henselae infection might be found in the blood donors in our region, thus, a detailed questionnaire prior to blood donation might be helpful to prevent transmission of B.henselae by blood transfusion.

Bartonella infection in immunocompromised hosts: immunology of vascular infection and vasoproliferation.

Most infections by genus Bartonella in immunocompromised patients are caused by B. henselae and B. quintana. Unlike immunocompetent hosts who usually develop milder diseases such as cat scratch disease and trench fever, immunocompromised patients, including those living with HIV/AIDS and posttransplant patients, are more likely to develop different and severe life-threatening disease. This paper will discuss Bartonella's manifestations in immunosuppressed patients and will examine Bartonella's interaction with the immune system including its mechanisms of establishing infection and immune escape. Gaps in current understanding of the immunology of Bartonella infection in immunocompromised hosts will be highlighted.

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.

Q fever endocarditis in Romania: the first cases confirmed by direct sequencing.

Infective endocarditis (IE) is a serious, life-threatening disease with highly variable clinical signs, making its diagnostic a real challenge. A diagnosis is readily made if blood cultures are positive, but in 2.5 to 31% of all infective endocarditis cases, routine blood cultures are negative. In such situations, alternative diagnostic approaches are necessary. Coxiella burnetii and Bartonella spp. are the etiological agents of blood culture-negative endocarditis (BCNE) most frequently identified by serology. The purpose of this study is to investigate the usefulness of molecular assays, as complementary methods to the conventional serologic methods for the rapid confirmatory diagnostic of Q fever endocarditis in patients with BCNE. Currently, detection of C. burnetii by culture or an antiphase I IgG antibody titers >800 represents a major Duke criterion for defining IE, while a titers of >800 for IgG antibodies to either B. henselae or B. quintana is used for the diagnosis of endocarditis due to Bartonella spp. We used indirect immunofluorescence assays for the detection of IgG titers for C. burnetii, B. henselae and B. quintana in 57 serum samples from patients with clinical suspicion of IE. Thirty three samples originated from BCNE patients, whereas 24 were tested before obtaining the blood cultures results, which finally were positive. The results of serologic testing showed that nine out of 33 BCNE cases exhibited antiphase I C. burnetii IgG antibody titer >800, whereas none has IgG for B. henselae or B. quintana. Subsequently, we used nested-PCR assay for the amplification of C. burnetii DNA in the nine positive serum samples, and we obtained positive PCR results for all analyzed cases. Afterwards we used the DNA sequencing of amplicons for the repetitive element associated to htpAB gene to confirm the results of nested-PCR. The results of sequencing allowed us to confirm that C. burnetii is the causative microorganism responsible for BCNE. In conclusion, the nested PCR amplification followed by direct sequencing is a reliable and accurate method when applied to serum samples, and it may be used as an additional test to the serological methods for the confirmatory diagnosis of BCNE cases determined by C. burnetii.

Systemic Bartonellosis Manifesting With Endocarditis and Membranoproliferative Glomerulonephritis.

Cat scratch disease caused by Bartonella species is mostly benign and self-limiting condition. Systemic infection is uncommon in immunocompetent host. We describe the case of a 66-year-old male who presented with sudden painless left eye blindness and brown-colored urine. Laboratory findings revealed progressively rising serum creatinine in association with nephrotic-range proteinuria at 7 g/day and glomerular hematuria on urinalysis. An echocardiogram demonstrated mitral and tricuspid valve vegetations despite multiple negative blood cultures. The left eye blindness was attributed to retinal artery occlusion from septic valvular embolus. Kidney biopsy showed membranoproliferative glomerulonephritis pattern of injury with "full house" pattern on immunofluorescent staining with subendothelial deposits on electron microscopy. Markedly elevated IgG (immunoglobulin G) titers for B henselae and B quintana were discovered. The patient had several cats at home. Kidney failure rapidly progressed to require hemodialysis. Once the diagnosis of systemic bartonellosis was confirmed, doxycycline (for 4 months) with rifampicin (for 3 months) were initiated. Repeat echocardiogram in 4 months demonstrated a resolution of valvular vegetations; however, the left eye blindness was permanent. In the present case the correct diagnosis of systemic bartonellosis allowed institution of appropriate antibiotic therapy and to also achieve a partial recovery of renal function and to discontinue hemodialysis.

Seroprevalence of Bartonella spp. infection in HIV patients in Catalonia, Spain.

BACKGROUND: Although the first clinical descriptions of Bartonella infection were associated with immunocompromised patient with bacillary angiomatosis, we currently know that this organism is directly involved in diseases affecting a large number of patients, regardless of their immune status. Cat scratch disease, hepatic peliosis, and some cases of bacteraemia and endocarditis, are directly caused by some species of the genus Bartonella. The purpose of this study was to determinate the prevalence of IgG antibodies against Bartonella henselae and B. quintana in HIV patients and to identify the epidemiological factors involved. METHODS: Serum samples were collected from HIV patients treated at Hospital de Sabadell. Antibodies to B. henselae and B. quintana from 340 patients were examined by indirect immunofluorescence assay (IFA). Significance levels for univariate statistical test were determined by the Mann-Whitney U test and chi2 test. RESULTS: Of 340 patients, 82 were women and 258 men, with a median age of 42.21 +/- 10.35 years (range 16-86 years). Seventy-six (22.3%) patients reacted with one or more Bartonella antigens. Of all the factors concerning the seroprevalence rate being studied (age, sex, intravenous drugs use, alcohol consumption, CD4 levels, AIDS, HCV, HBV, residential area), only age was statistically significant. CONCLUSION: A high percentage of HIV patients presents antibodies to Bartonella and is increasing with age.

Evaluation of cell culture-grown Bartonella antigens in immunofluorescent antibody assays for the serological diagnosis of bartonellosis in dogs.

BACKGROUND: Because of poor sensitivity and questionable specificity of immunofluorescent antibody assays (IFAs), serological diagnosis of Bartonella species infections in dogs remains challenging. Despite limitations, IFA testing is the historical "gold standard" for Bartonella serodiagnosis in animals and humans. Because most diagnostic laboratories test against only 1 or 2 Bartonella spp., testing against a broader panel of Bartonella antigens may enhance diagnostic sensitivity and specificity. OBJECTIVE: To evaluate the sensitivity and specificity of Bartonella IFA using 8 cell culture-grown Bartonella spp. isolates. ANIMALS: Archived serum samples from 34 Bartonella spp. naturally exposed, polymerase chain reaction (PCR)-positive dogs and from 26 PCR-negative and IFA-negative dogs. METHODS: Bartonella IFA sensitivity and specificity were assessed using cell culture-grown whole cell antigens derived from 3 Bartonella henselae (Bh) strains (Bh Houston 1, Bh San Antonio Type 2, Bh California 1), 3 Bartonella vinsonii subsp. berkhoffii genotypes (Bvb I, II, and III), Bartonella koehlerae (Bk), and Bartonella quintana (Bq). RESULTS: Only 62% of 34 Bartonella spp. PCR-positive dogs were seroreactive to any of the 8 Bartonella IFA antigens, indicating low IFA sensitivity. PCR-positive dogs were most often IFA seroreactive to Bq (n = 15), to Bvb II (n = 13), or to both (n = 9) antigens. Of the 26 previously IFA-negative/PCR-negative dogs, 4 (15%) were seroreactive using the expanded antigen panel. CONCLUSION AND CLINICAL IMPORTANCE: Despite IFA testing of dogs against 8 different Bartonella isolates, IFA sensitivity remained poor, and specificity was only 85%. Development of a reliable serological assay is needed to facilitate the diagnosis of Bartonella infection in dogs.

Presumed oculoglandular syndrome from Bartonella quintana.

BACKGROUND: To describe a case of clinically diagnosed oculoglandular syndrome in a 17-year-old patient that was presumed to be due to Bartonella quintana, as suggested by a positive serologic titer. METHODS: The patient presented to the Massachusetts Eye and Ear Infirmary emergency room with signs and symptoms suggestive of oculoglandular syndrome. He had a follicular conjunctivitis with a conjunctival granuloma of the right eye and an ipsilateral large, tender submandibular lymph node. He had recently acquired a kitten and a clinical diagnosis of cat-scratch disease was made. A laboratory workup was initiated to determine the cause of this clinical presentation and empirical treatment with antibiotics was started. RESULTS: All laboratory results were negative or normal except for the IgM titer to Bartonella quintana, which was elevated. The patient responded well to treatment and his symptoms resolved within a few weeks. DISCUSSION: Bartonella quintana infection, a pathogen prevalent in HIV-infected, homeless, or alcoholic patients, is a possible etiologic agent of cat-scratch disease and the associated condition of oculoglandular syndrome.

Presence of Bartonella spp. in various human populations.

Bartonella spp. bacteria are significant human pathogens and the agents of bacterial zoonosis acquired from an animal companion. The aim of the study was to determine the seroprevalence of two of the most common Bartonella species B. henselae and B. quintana in various human populations. The studied groups included: alcoholics, intravenous drug users, veterinarians, cats' owners. Blood samples were collected and cultured on chocolate agar plates and in mouse fibroblasts L-929 cell line culture. The levels of Bartonella henselae IgM and IgG antibodies were determined by indirect immunofluorescence assay. Specific B. henselae IgG were detected in 48.3% of homeless alcoholics, in 45.0% veterinarians and in 53.3% cats' owners. The differences in the prevalence of B. henselae antibodies between the studied groups and a control group were statistically supported. No homeless intravenous drug users had specific B. henselae and B. quintana antibodies. High titers of B. quintana IgG antibodies were detected in two homeless alcoholics. Bartonella spp. was cultured on chocolate blood agar plates from blood samples from 2 alcoholics. The isolates were identified as B. henselae by PCR amplification of the riboflavin synthase gene (ribC). The results prove that B. henselae and B. quintana, emerging human pathogens, are present and widely distributed in Poland in such specific risk groups as: alcoholics, veterinarians and cats' owners.

[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-ASSOCIATED NEURORETINITIS: LONGITUDINAL SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHIC FINDINGS.

PURPOSE: To report an unusual case of neuroretinitis caused by Bartonella quintana and its spectral-domain optical coherence tomographic (SD-OCT) features. METHODS: A 12-year-old girl presented with unilateral neuroretinitis with stellate maculopathy. Bartonellosis was confirmed after serologic testing for antibodies to B. quintana. RESULTS: Color photograph of the right eye revealed papillitis and stellate macular exudation. spectral-domain optical coherence tomography of the right eye revealed hyperreflective dots in the outer nuclear and outer plexiform layers, as well as disruption and loss of the external limiting membrane, ellipsoid zone, and interdigitation zone in the foveal area. CONCLUSION: The authors report an unusual case of neuroretinitis by B. quintana and its spectral-domain optical coherence tomographic findings.

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.

Epidemiological studies on Bartonella quintana infections among homeless people in Tokyo, Japan.

In an epidemiological investigation of trench fever in Japan, we compared the seroprevalence of Bartonella quintana in homeless people and in the general population. In homeless rescue outreach programs held in Tokyo from May 2001 to March 2003, 151 blood samples were taken from non-hospitalized homeless people. The prevalence of IgM and IgG antibodies against B. quintana in these people was compared with that in 200 healthy blood donors using a commercially available indirect fluorescent antibody test. Although IgG titers of > or = 1:128 were found in 57% (86/151) of homeless people and 51% (101/200) of blood donors, high titers of > or = to 1:1,024 were encountered only in homeless people (11%, 16/151). Attempts to isolate B. quintana from the blood of homeless people were unsuccessful, but polymerase chain reaction based detection, using Bartonella genus specific primers, demonstrated the presence of B. quintana DNA in the blood of 10 homeless people. Our data suggest that urban trench fever is endemic among the Japanese homeless population.

Quintessential Culture-Negative Endocarditis.

Bartonella spp are important causes of culture-negative endocarditis, generally causing a subacute insidious form of endocarditis, often leading to a delay in diagnosis. Most patients have fever and often present with signs and symptoms of heart failure. The diagnosis is frequently established only on meticulous examination of the resected heart valve with the polymerase chain reaction technique. We present a case of B quintana mitral and aortic valve endocarditis with associated severe valvular insufficiency and decompensated heart failure precipitated by Streptococcus pneumoniae bacteremia, necessitating urgent surgical valve replacement. Pathologic examination of the valve complemented by serologic and molecular testing established the surprising diagnosis of B quintana endocarditis.

Ectoparasitism and vector-borne diseases in 930 homeless people from Marseilles.

Homeless people are particularly exposed to ectoparasites, but their exposure to arthropod-borne diseases has not been evaluated systematically. A medical team of 27 persons (7 nurses, 6 infectious disease residents or fellows, 2 dermatologists, and 12 infectious disease specialists) visited the 2 shelters in Marseilles, France, for 4 consecutive years. Homeless volunteers were interviewed, examined, and received care; and blood was sampled for cell counts and detection of bacteremia, antibodies to louse-borne (Rickettsia prowazekii, Bartonella quintana, and Borrelia recurrentis), flea-borne (R. typhi, R. felis), mite-borne (R. akari), and tick-borne (R. conorii) bacterial agents. We selected sex- and age-adjusted controls among healthy blood donors. Over 4 years, 930 homeless people were enrolled. Lice were found in 22% and were associated with hypereosinophilia (odds ratio, 5.7; 95% confidence intervals, 1.46-22.15). Twenty-seven patients (3%) with scabies were treated with ivermectin. Bartonella quintana was isolated from blood culture in 50 patients (5.3%), 36 of whom were treated effectively. The number of bacteremic patient increased from 3.4% to 8.4% (p = 0.02) over the 4 years of the study. We detected a higher seroprevalence to Borrelia recurrentis, R. conorii, and R. prowazekii antibodies in the homeless. Our study shows a high prevalence of louse-borne infections in the homeless and a high degree of exposure to tick-borne diseases and scabies. Despite effective treatment for Bartonella quintana bacteremia and the efforts made to delouse this population, Bartonella quintana remains endemic, and we found hallmarks of epidemic typhus and relapsing fever. The uncontrolled louse infestation of this population should alert the community to the possibility of severe re-emerging louse-borne infections.

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.