Bartonella infections diagnosed in the French reference center, 2014-2019, and focus on infections in the immunocompromised.

We studied retrospectively 651 PCR-confirmed Bartonella infections diagnosed at the French reference center for bartonellosis from 2014 to 2019. The most common form was cat-scratch disease (89%) followed by endocarditis (9%). Disseminated forms (2%) mainly presented as bacillary angiomatosis or peliosis hepatis in solid organ transplant recipients.

Infectious and Autoimmune Causes of Encephalitis in Children.

BACKGROUND AND OBJECTIVES: Encephalitis can result in neurologic morbidity and mortality in children. Newly recognized infectious and noninfectious causes of encephalitis have become increasingly important over the past decade. METHODS: We retrospectively reviewed medical records from pediatric patients in Houston diagnosed with encephalitis in both an urban and rural catchment area between 2010 and 2017. We conducted an investigation to understand the etiology, clinical characteristics, and diagnostic testing practices in this population. RESULTS: We evaluated 231 patients who met the case definition of encephalitis, among which 42% had no recognized etiology. Among those with an identified etiology, the most common were infectious (73; 31%), including viral (n = 51; 22%), with the most frequent being West Nile virus (WNV; n = 12), and bacterial (n = 19; 8%), with the most frequent being Bartonella henselae (n = 7). Among cases of autoimmune encephalitis (n = 60; 26%), the most frequent cause was anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis (n = 31). Autoimmune causes were seen more commonly in female (P < .01) patients. Testing for herpes simplex virus and enterovirus was nearly universal; testing for anti-NMDAR encephalitis, WNV, and Bartonella was less common. CONCLUSIONS: WNV was the most common infectious cause of encephalitis in our pediatric population despite lower testing frequency for WNV than herpes simplex virus or enterovirus. Increasing testing for anti-NMDAR encephalitis resulted in frequent identification of cases. Increased awareness and testing for WNV and Bartonella would likely result in more identified causes of pediatric encephalitis. Earlier etiologic diagnosis of encephalitides may lead to improve clinical outcomes.

Ahnak-knockout mice show susceptibility to Bartonella henselae infection because of CD4+ T cell inactivation and decreased cytokine secretion.

The present study evaluated the role of AHNAK in Bartonella henselae infection. Mice were intraperitoneally inoculated with 2 × 108 colony-forming units of B. henselae Houston-1 on day 0 and subsequently on day 10. Blood and tissue samples of the mice were collected 8 days after the final B. henselae injection. B. henselae infection in the liver of Ahnak-knockout and wild-type mice was confirmed by performing polymerase chain reaction, with Bartonella adhesion A as a marker. The proportion of B. henselaeinfected cells increased in the liver of the Ahnak-knockout mice. Granulomatous lesions, inflammatory cytokine levels, and liver enzyme levels were also higher in the liver of the Ahnak-knockout mice than in the liver of the wild-type mice, indicating that Ahnak deletion accelerated B. henselae infection. The proportion of CD4＋interferon-γ (IFN-γ)＋ and CD4＋interleukin (IL)-4＋ cells was significantly lower in the B. henselae-infected Ahnak-knockout mice than in the B. henselae-infected wild-type mice. In vitro stimulation with B. henselae significantly increased IFN-γ and IL-4 secretion in the splenocytes obtained from the B. henselae-infected wild-type mice, but did not increase IFN-γ and IL-4 secretion in the splenocytes obtained from the B. henselae-infected Ahnak-KO mice. In contrast, IL-1α, IL-1ß, IL-6, IL-10, RANTES, and tumor necrosis factor-α secretion was significantly elevated in the splenocytes obtained from both B. henselae-infected wild-type and Ahnak-knockout mice. These results indicate that Ahnak deletion promotes B. henselae infection. Impaired IFN-γ and IL-4 secretion in the Ahnak-knockout mice suggests the impairment of Th1 and Th2 immunity in these mice. [BMB Reports 2019; 52(4): 289-294].

Cat scratch disease during etanercept therapy in a rheumatoid arthritis patient. / Enfermedad por arañazo de gato en paciente con artritis reumatoidea tratado con etanercept.

Cat scratch disease (CSD) is an infectious disorder caused by Bartonella henselae and characterized by fever and granulomatous lymphadenopathy. Immunosuppression is a risk factor for the development of atypical forms of the disease. We report the case of a 52-year-old woman who presented with fever and bilateral inguinal lymph node enlargement. She did not have apparent contact with animals. The patient was receiving etanercept therapy for rheumatoid arthritis. Lymph node biopsy demonstrated granulomatous lymphadenitis. She was successfully managed by discontinuing etanercept and by treatment with minocycline. She developed clinical remission and typical seroconversion. Infection with Bartonella should be considered in the differential diagnosis in rheumatoid arthritis patients with lymphadenopathy of unknown origin.

Cat Scratch Disease: Not a Benign Condition.

PURPOSE: Describe a case series of ocular Cat-scratch-disease (CSD) with vision-threatening findings and poor outcomes, indicating severity of disease. METHODS: Retrospective case series from the Uveitis Department of São Paulo Federal University from 2011 to 2015. RESULTS: In this period, six eyes of four patients had confirmed diagnosis of CSD. Two were male and two female. Mean age was 24.8 years old [7-45]. Two had bilateral disease. Visual acuity at presentation ranged from no light perception to 20/25. Three patients were treated with doxycycline and one with clarithromycin and prednisone. Visual outcome after treatment ranged from counting fingers to 20/20: 5/6 eyes had final visual acuity of less than 20/40 and 3/6 had final visual acuity equal or less than 20/400. CONCLUSION: Although usually described as a benign disease with spontaneous resolution, CSD can present with atypical manifestations such as vascular angiomatous lesions, serous retinal detachment, and vascular occlusion syndromes, carrying a severe course and guarded prognosis.

[A negleted bacteria with a case: Bartonella henselae]. / Bir olgu ile ihmal edilen bir etken: Bartonella henselae.

Bartonella henselae the causative agent of cat scratch disease (CSD), is a gram-negative, coccobacillus, facultative intracellular bacterium CSD usually presents as a clinical form of benign local lymphadenopathy (LAP) but sometimes it may progress to severe life threatening complications. Despite the fact that CSD is known to be a common disease, which is one of the important causes of local LAPs in the world, there are few publications in our country. For the diagnosis, the clinician should suspect for CSD and has to ask to the patient whether there is a story of cat scratch or not. In our country the diagnosis of CSD is usually done by invasive pathological examination instead of simple serological tests. In this report, a 14 years old case with CSD with antibody titers of 1/384 IgM, 1/2048 IgG B.henselae antibody determined by indirect fluorescent antibody (IFA) method in serum and B.henselae positivity by polymerase chain reaction (PCR) from LAP sample of the patient with axillary LAP was presented. Even though molecular techniques have been used for the diagnosis of the previous reported cases, it is the first B.henselae positive case in our country detected with PCR. In the history of the case it was learned that the patient was scratched by a street cat few months ago and the axillary LAP developed 4-5 weeks later. Axillary ultrasonography shawed abscesses with the largest 22 x 44 mm compatible with LAP. No growth was detected in the LAP biopsy specimen culture. Leucocyte count was normal but sedimentation rate (68 mm/h), and C-reactive protein (41.7 mg/L) were higher.Therapy was started with azitromycin 500 mg/day but two weeks later as there was no regression of LAP, considering the development of resistance, the treatment was changed to doxycycline 2 x 100 mg/day and rifampicin 1 x 300 mg/day. As the LAP was in abscess formation and the titers found in IFA was higher than the predictive value of B.henselae antibody titer for endocarditis, the treatment has been extended to four weeks and the patient has been cured. Especially children and adolescents are at very high risk for zoonotic infections transmitted from pets in our country due to the intense immigration to the city from the rural areas and the unconscious and uncontrolled livelihood of friendship with street animals. We should accept that this is not a rare condition, as the cat scratch disease can change from harmless to very serious forms the diagnosis and treatment should be quickly and carefully performed. Currently, serological examinations for Bartonella are rarely done in some certain reference laboratories in our country. The number of these laboratories should be increased or the usage of the tests in these reference laboratories should be at least expanded.

Hemophagocytic Lymphohistiocytosis Associated With Bartonella henselae Infection in an HIV-Infected Patient.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome that often occurs in immunocompromised patients. We report the first case of HLH due to Bartonella henselae infection in a patient with human immunodeficiency virus infection. Early recognition of HLH and B. henselae through liver biopsy and serological tests led to the patient's recovery.

[Cat scratch disease: still current zoonosis]. / Felinóza- stále aktuální zoonóza

OBJECTIVES: A retrospective evaluation of a group of patients which is focused on clinical picture, serological diagnosis, therapy and familial occurrence of the disease. MATERIAL AND METHODS: Cat scratch disease (CSD) was considered within the scope of a differential diagnosis of lymphadenopathy. Serological diagnosis was based on detection of antibodies against Bartonella henselae by indirect immunofluorescence, where the level of IgG antibodies of at least 1 : 256 or any positive level of IgM antibodies were considered positive for CSD. If a histological examination was conducted, the suspicion of CSD was supported by finding granulomatous inflammation. Macrolides were used for treatment in both children and adults. In addition to macrolides, doxycycline was used in adults. RESULTS: From 2004 to 2013, a total of 27 patients aged 7-73 years were diagnosed with CSD at the Clinic of Infectious Medicine, University Hospital in Ostrava. None of them suffered from immunodeficiency detected earlier. Diagnostic extirpation of a lymph node was performed in 5 patients diagnosed with granulomatous inflammation. Lymph node syndrome was observed in all patients, with cervical, inguinal and axillary nodes being most frequently affected. However, two patients had supraclavicular nodes affected and a 52-year-old woman had unusual swelling of lymphatic tissue in the scapular region with skin lesions. Lymph node syndrome accompanied by encephalopathy was observed in one 50-year-old patient. Positive IgM antibodies were detected in only 8 patients. There were two cases of familial occurrence affecting 2 and 3 family members. Antibiotic therapy with full resolution of clinical findings was successful in 24 patients, including the patient with encephalopathy. In spite of the antibiotic treatment, three patients developed lymph node colliquation requiring surgical intervention. CONCLUSIONS: Atypical lymph node localization in 3 patients, encephalopathy in 1 patient, positive levels of IgM antibodies in 8 only patients, delayed antibodies production in 4 patients and antibiotic therapy coupled with extirpation of colliquated lymph nodes in 3 patients were found in the group of 27 patients.

A case report of seronegative cat scratch disease, emphasizing the histopathologic point of view.

Cat scratch disease, necrotizing granulomatous lymphadenitis caused by Bartonella henselae, usually benign and self-limited. However, various clinical manifestations and no pathognomonic histopathologic features can lead to misinterpretations and diagnostic disputes. We report a case of cat scratch disease in a 39-yr-old male patient with fever and left axillary lymphadenitis. He had a history of cat bite on the left hand dorsum. On excision, the lymph node showed follicular hyperplasia, stellate microabscesses with a rim of granulomatous inflammation. Warthin-Starry silver staining showed many clumps of silver-stained bacilli within the necrotic foci. Serological tests were negative. Diagnosis was established by PCR analysis. VIRTUAL SLIDES: The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1877499238123059.

Exactitud y utilidad diagnóstica de la IgM en infecciones por Bartonella henselae / Accuracy and diagnostic utility of IgM in Bartonella henselae infections

Introduction: Laboratory diagnosis of cat scratch disease (CSD) is based on the determination of specific antibodies anti-Bartonella henselae by different techniques. The CDC recommends IgG by immunofluorescent assay (IFA) as the gold standard. Objective: To determine the accuracy and diagnostic utility of anti-B.henselae IgM by IFA for CSD. Material and Methods: Anti-B. henselae IgG was determined in serum of 108 patients with CSD suspicion; in addition, specific IgM was determined separately and blindly by two thoroughly trained laboratory professionals. We calculated sensitivity (S), specificity (Sp), predictive values both positive (PPV) and negative (NPV), and likelihood ratio (LR) for IgM positive (LR +) and negative (LR-). Results: In 37 patients with positive anti-B.henselae IgG, IgM was positive in 16 and negative in 21; in 71 patients with negative IgG, IgM was negative in 69 and positive in 2. Therefore, IgM showed S 43%, E 97%, PPV 88%, NPV 77%, LR (+) 15 and LR (-) 0.58. Conclusions: The results show that a positive IgM supports, but a negative one does not rule out a B. henselae infection. Therefore, IgG should be still considered as the gold standard for the diagnosis of CSD.

Introducción: El diagnóstico de laboratorio de la enfermedad por arañazo de gato (EAG) se basa en la determinación de anticuerpos específicos anti-Bartonella henselae por distintas técnicas. El CDC de E.U.A. recomienda como estándar de oro la IgG mediante inmunofluorescencia (IF). Objetivo: Determinar la exactitud y utilidad diagnóstica de la IgM anti-B. henselae por IF para EAG. Material y Método: En suero de 108 pacientes a quienes se realizó IgG anti-B. henselae por sospecha de EAG, se determinó la presencia de IgM específica, en forma separada y ciega por dos profesionales de laboratorio ampliamente entrenados. Se calculó sensibilidad (S), especificidad (E), valores predictores positivo (VPP) y negativo (VPN) y likelihood ratio (LR) para una IgM positiva (LR+) y negativa (LR-). Resultados: En 37 pacientes con IgG anti-B. henselae positiva, la IgM fue positiva en 16 y negativa en 11; en 71 pacientes con IgG negativa, la IgM fue negativa en 69 y positiva en 2. Por consiguiente, la IgM presentó S 43%, E 97%, VPP 88%, VPN 77%, LR(+) 15 y LR(-) 0,58. Conclusiones: Los resultados sugieren que una IgM positiva apoya el diagnóstico de EAG, pero una negativa no permite descartarlo. Por tanto, la IgG debe seguir considerándose como el estándar de oro para el diagnóstico de infecciones por B. henselae.

Atypical form of cat scratch disease in immunocompetent patient.

INTRODUCTION: Cat scratch disease (CSD) is an acute infectious disease with benign course caused by the bacteria Bartonella henselae. Clinically, it is usually manifested as regional lymphadenopathy and mild infective syndrome. Rare forms of the disease which usually occur in immunocompromised presons are: encephalitis, transverse myelitis, neuroretinitis, granulomatosus conjunctivitis, arthritis, hepatitis etc. CASE REPORT: We presented an atypical form of cat scratch disease in a young immunocompetent female person. The disease was manifested with prolonged fever, rash, purulent lymphadenitis and hepatitis. The diagnosis was based on characteristic patohystological finding and exclusion of the other causes of lymphadenopathy. The patient was treated by antibiotics for a few weeks, with surgical incision and drainage of the purulent lymphadenitis. CONCLUSION: Atypical forms of CSD could be an important differential-diagnostic problem, especially if there is no opportunity for serological confirmation of the disease.

Serum immunoglobulin G avidity test as a tool for improving diagnosis of cat scratch disease.

Cat scratch disease (CSD) is a common cause of subacute infectious regional lymphadenitis, caused by Bartonella henselae. Presently, detection of anti-B. henselae antibodies by immunofluorescence antibody assay or enzyme immunoassay (EIA) is the most widely used diagnostic test for CSD, but both are limited in establishing the timing of infection with B. henselae. In the present work we developed an avidity test for anti-B. henselae immunoglobulin G (IgG) based on EIA to distinguish recent from past CSD. We used 101 serum samples from 79 CSD patients with positive anti-B. henselae IgG as verified by EIA, and systematically developed an avidity assay using various detergent (urea) concentrations and incubation settings to optimize the test conditions to differentiate early CSD (less than 12 weeks) from late CSD (12 weeks or more). After serial experiments, the optimal conditions for performing the avidity test included incubation for 10 min at room temperature with 8 M urea at pH 7.4, and these parameters were used in the study. Our experiments showed that while the avidity indexes (AIs) of the early CSD samples were widely distributed, all the late CSD sera samples had AIs above 43, indicating that an AI <43 can serve as evidence of early CSD. The results of this study indicate that the avidity test can be useful in the serodiagnosis of CSD, particularly when anti-B. henselae IgM antibodies are not detected.

Cat scratch disease during pregnancy.

OBJECTIVE: To describe the pregnancy outcome, including long-term follow-up of the offspring, of pregnant women with cat scratch disease. METHODS: A surveillance study performed over 19 years identified eight pregnant women with cat scratch disease. A case of cat scratch disease was defined as a patient with a history of cat contact with regional lymphadenitis, other manifestations, or a combination of these consistent with the disease and one or more confirmatory laboratory tests. The clinical and laboratory manifestations and pregnancy outcome of all women diagnosed with cat scratch disease during pregnancy are described. RESULTS: Five of the eight pregnant women had typical disease with regional lymphadenitis; two had regional lymphadenitis with arthralgia, myalgia, and erythema nodosum; and one had neuroretinitis. Delayed diagnosis was common, although all women had a history of recent cat exposure. One woman who presented with clinical cat scratch disease during the first month of pregnancy had a spontaneous abortion. Another elected to terminate the pregnancy because of concerns related to radiation associated with abdominal computed tomography scan performed as part of an evaluation for suspected malignancy. The other six women gave birth to healthy newborns without congenital anomalies. No sequelae were recorded in mothers or children during a median follow-up of 4.5 years (range 0.5-9.5 years). CONCLUSION: With the exception of one early spontaneous abortion in which causality to cat scratch disease could not be established, neither deleterious effects of cat scratch disease on newborns nor reports of long-term sequelae were found. Physicians, especially family physicians and obstetrician-gynecologists need to be more familiar with the clinical manifestations of cat scratch disease. Close monitoring of infected women during pregnancy is advisable until more data are available to determine the optimal diagnostic and therapeutic approach.

Identification of candidate proteins for the diagnosis of Bartonella henselae infections using an immunoproteomic approach.

Bartonella henselae is an emerging gram-negative facultative intracellular pathogen transmitted via Ctenocephalides felis (cat fleas) or cat scratches. Bartonellosis is present mainly in the form of cat scratch disease (CSD), bacillary angiomatosis and infective endocarditis (IE). The methods used to diagnose B. henselae rely on culturing, immunofluorescent assays and molecular techniques. The objective of the present study was to identify candidate proteins for the serodiagnosis of bartonellosis with the differential discrimination of both clinical scenarios: CSD and IE. For this, an immunoproteomic approach combined with 2-DE, immunoblotting and matrix-assisted laser desorption/ionization time-of-flight MS has been developed. Immunoproteomic profiles of sera collected from patients with CSD and IE were compared with those of blood donors. We identified several candidate proteins as phage-encoding Pap31 protein and an outer membrane protein of BH11510 that, in our view, might be useful for the serodiagnosis of bartonellosis.

Proteomic analysis of the bacterial pathogen Bartonella henselae and identification of immunogenic proteins for serodiagnosis.

Bartonella henselae is a slow growing, fastidious and facultative intracellular pathogen causing cat scratch disease and vasculoproliferative disorders. To date, knowledge about the pathogenicity of this human pathogenic bacterium is limited and, additionally, serodiagnosis still needs further improvement. Here, we investigated the proteome of B. henselae using 2-D SDS-PAGE and MALDI-TOF-MS. We provide a comprehensive 2-D proteome reference map of the whole cell lysate of B. henselae with 431 identified protein spots representing 191 different proteins of which 16 were formerly assigned as hypothetical proteins. To unravel immunoreactive antigens, we applied 2-D SDS-PAGE and subsequent immunoblotting using 33 sera of patients suffering from B. henselae infections. The analysis revealed 79 immunoreactive proteins of which 71 were identified. Setting a threshold of 20% seroreactivity, 11 proteins turned out to be immunodominant antigens potentially useful for an improved Bartonella-specific serodiagnosis. Therefore, we provide for the first time (i) a comprehensive 2-D proteome map of B. henselae for further proteome-based studies focussed on the pathogenicity of B. henselae and (ii) an integrated view into the humoral immune responses targeted against this newly emerged human pathogenic bacterium.

Lymphadenopathy in a novel mouse model of Bartonella-induced cat scratch disease results from lymphocyte immigration and proliferation and is regulated by interferon-alpha/beta.

In immunocompetent humans, cat scratch disease (CSD) is elicited by the Gram-negative bacterium Bartonella henselae and is characterized by a benign regional lymphadenopathy, the pathogenesis of which is poorly understood. Here, we describe a novel mouse model of Bartonella-induced CSD-like disease that allowed us to investigate the mechanisms leading to lymphadenopathy in vivo. In wild-type mice, a subcutaneous inoculation of either viable or inactivated B. henselae led to a strong swelling of the draining lymph node, which was long-lasting despite the rapid elimination of the bacteria. Carboxyfluorescein- and bromodesoxyuridine-labeling experiments showed that lymph node enlargement resulted from modified immigration and enhanced proliferation of lymphocytes, preferentially of B cells. A comparative analysis of B. henselae and the rodent pathogen B. grahamii in wild-type versus interferon-alpha/beta-receptor I chain-deficient mice revealed that interferon-alpha/beta is not only differentially induced by these two Bartonella species but also exerts an inhibitory effect on the development of lymphadenopathy both in vitro and in vivo. These data demonstrate that the lymphadenopathy of human CSD can be reproduced and studied in a mouse model and provide the first insights into the underlying immunological mechanisms.

Characterization of an immunogenic outer membrane autotransporter protein, Arp, of Bartonella henselae.

Bartonella henselae is a recently recognized pathogenic bacterium associated with cat scratch disease, bacillary angiomatosis, and bacillary peliosis. This study describes the cloning, sequencing, and characterization of an antigenic autotransporter gene from B. henselae. A cloned 6.0-kb BclI-EcoRI DNA fragment expresses a 120-kDa B. henselae protein immunoreactive with 21.2% of sera from patients positive for B. henselae immunoglobulin G antibodies by indirect immunofluorescence, with 97.3% specificity and no cross-reactivity with antibodies against various other organisms. DNA sequencing of the clone revealed one open reading frame of 4,320 bp with a deduced amino acid sequence that shows homology to the family of autotransporters. The autotransporters are a group of proteins that mediate their own export through the outer membrane and consist of a passenger region, the alpha-domain, and an outer membrane transporter region, the beta-domain. The passenger domain shows homology to a family of pertactin-like adhesion proteins and contains seven, nearly identical 48-amino-acid repeats not found in any other bacterial or Bartonella DNA sequences. The passenger alpha-domain has a calculated molecular mass of 117 kDa, and the transporter beta-domain has a calculated molecular mass of 36 kDa. The clone expresses a 120-kDa protein and a protein that migrates at approximately 38 kDa exclusively in the outer membrane protein fraction, suggesting that the 120-kDa passenger protein remains associated with the outer membrane after cleavage from the 36-kDa transporter.

Isolated hepatic involvement of cat scratch disease in immunocompetent adults: Enhanced magnetic resonance imaging, pathological findings, and molecular analysis--two cases.

Visceral involvement in absence of lymphadenopathy is a rare manifestation in cat scratch disease; hepatic granulomas are rare, representing 0.3% of systemic manifestations of cat scratch disease, and gallbladder extension is a singular case. The present article refers to 2 rare cases of visceral cat scratch disease in immunocompetent adults with hepatic granulomatous inflammation, caused by Bartonella henselae infection, with gallbladder involvement in 1 case and no lymphadenopathy. Histological features demonstrated the presence of inflammatory necrotizing granulomatous nonneoplastic process. Molecular studies (polymerase chain reaction) were performed to confirm the infectious etiology.

Prevalence of Bartonella henselae antibodies in serum of cats with and without clinical signs of central nervous system disease.

Bartonella henselae is occasionally associated with neurological dysfunction in people and some experimentally infected cats. The purpose of this study was to determine whether B henselae seroprevalence or titer magnitude varies among cats with neurological disease, cats with non-neurological diseases, and healthy cats while controlling for age and flea exposure. There was no difference in B henselae seroprevalence rates between cats with seizures and cats with other neurological diseases. Cats with non-neurological disease and healthy cats were more likely than cats with neurological disease to be seropositive. While the median B henselae antibody titer was greater in cats with seizures than in cats with other neurological disease, the median B henselae antibody titer was also greater in healthy cats than cats with seizures. The results suggest that titer magnitude cannot be used alone to document clinical disease associated with B henselae infection and that presence of B henselae antibodies in serum of cats with neurological disease does not prove the clinical signs are related to B henselae.