Application of metagenomic next-generation sequencing in the diagnosis of Bartonella neuroretinitis: a case report and literature review

BACKGROUND

Cat-scratch disease (CSD) is caused by Bartonella henselae infection. In atypical cases of CSD, pathogen determination is challenging. We report a case of Bartonella neuroretinitis with neither a clear history of scratches nor typical general symptoms. The diagnosis was made using metagenomic next-generation sequencing (mNGS), a high-throughput sequencing technology.

CASE PRESENTATION

A female patient presented to the ophthalmologist with complaint of blurred vision in her right eye. Although with history of raising a cat, she reported no clear history of scratches or typical general symptoms, except a fever of unknown origin which resolved spontaneously. The best corrected visual acuity (BCVA) of the right eye was count fingers. Fundus examination showed optic disc oedema, macular exudates and inferior exudative retinal detachment. Laboratory examination results showed increased value of serum C-reactive protein and erythrocyte sedimentation rate. Ocular involvement of toxoplasmosis, syphilis and tuberculosis were excluded. To identify the possible causative pathogen of the disease, mNGS of aqueous humour sample was performed and 521 reads of B. henselae were identified. Serological test results further showed a positive immunoglobulin G (IgG) titre of 1:64. Taking the contact history, clinical manifestations, mNGS and serological results into consideration, the diagnosis of Bartonella neuroretinitis (ocular CSD) was made. After appropriate treatment, the BCVA of the right eye improved to 20/25 in the last follow-up. Fundus examination showed a normal optic disc and macula, and the exudates had reduced.

CONCLUSION

mNGS, a fast and unbiased method, can be used to detect B. henselae (if present) in intraocular fluid samples.; however, the results should be interpreted together with the clinical symptoms and other auxiliary test results.

Bartonella Henselae Related Unilateral Anterior Uveitis and Subsequent Multifocal Retinitis in a Case Under Certolizumab Treatment

Introduction

A case of ocular bartonellosis under anti-tumour necrosis factor treatment is described.

Case description

A 29-year-old woman with psoriasis who had been on certolizumab treatment was examined with a left visual deterioration following a fever bout, malaise, and placoid erythematous rashes on her neck. As there was acute anterior uveitis in her left eye, it was recommended to stop certolizumab treatment for a possible infectious aetiology. However, her physician elected to continue the certolizumab treatment. Ten days later, the patient noticed further visual decline despite the topical steroid treatment. This time, there were scattered yellow-white small retinitis foci at the left posterior pole. Infectious agents were searched and while Bartonella henselae antibodies were negative for immunoglobulin M, the immunoglobulin G titre was 1/80. Clinical findings were improved with the systemic treatment of oral trimethoprim-sulfamethoxazole (160/800 mg twice daily for six weeks) and azithromycin (500 mg once daily for two weeks).

Discussion

Though extremely rare, ocular bartonellosis should be kept in mind in patients on anti-tumour necrosis factor treatment as rapid and accurate diagnosis may end up with an excellent visual outcome and full recovery.

LEARNING POINTS

Anti-tumour necrosis factor treatment is fraught with several ocular side effects including myositis, corneal infiltrates, scleritis, uveitis, optic neuritis, retinal vasculitis and ophthalmoplegia.When a new uveitis episode occurs in cases undergoing anti-tumour necrosis factor therapy, its cause poses a diagnostic challenge as it can have either an infectious or a non-infectious nature.Though very rare, ocular bartonellosis may also occur in immunocompromised individuals and a prompt diagnosis and appropriate treatment can lead to an excellent visual recovery.

Clinicopathological differences between Bartonella and other bacterial endocarditis-related glomerulonephritis - our experience and a pooled analysis

Background

Although Staphylococcus aureus is the leading cause of acute infective endocarditis (IE) in adults, Bartonella spp. has concomitantly emerged as the leading cause of "blood culture-negative IE" (BCNE). Pre-disposing factors, clinical presentation and kidney biopsy findings in Bartonella IE-associated glomerulonephritis (GN) show subtle differences and some unique features relative to other bacterial infection-related GNs. We highlight these features along with key diagnostic clues and management approach in Bartonella IE-associated GN.

Methods

We conducted a pooled analysis of 89 cases of Bartonella IE-associated GN (54 published case reports and case series; 18 published conference abstracts identified using an English literature search of several commonly used literature search modalities); and four unpublished cases from our institution.

Results

Bartonella henselae and Bartonella quintana are the most commonly implicated species causing IE in humans. Subacute presentation, affecting damaged native and/or prosthetic heart valves, high titer anti-neutrophil cytoplasmic antibodies (ANCA), mainly proteinase-3 (PR-3) specificity, fastidious nature and lack of positive blood cultures of these Gram-negative bacilli, a higher frequency of focal glomerular crescents compared to other bacterial infection-related GNs are some of the salient features of Bartonella IE-associated GN. C3-dominant, but frequent C1q and IgM immunofluorescence staining is seen on biopsy. A "full-house" immunofluorescence staining pattern is also described but can be seen in IE -associated GN due to other bacteria as well. Non-specific generalized symptoms, cytopenia, heart failure and other organ damage due to embolic phenomena are the highlights on clinical presentation needing a multi-disciplinary approach for management. Awareness of the updated modified Duke criteria for IE, a high index of suspicion for underlying infection despite negative microbiologic cultures, history of exposure to animals, particularly infected cats, and use of send-out serologic tests for Bartonella spp. early in the course of management can help in early diagnosis and initiation of appropriate treatment.

Conclusion

Diagnosis of IE-associated GN can be challenging particularly with BCNE. The number of Bartonella IE-associated GN cases in a single institution tends to be less than IE due to gram positive cocci, however Bartonella is currently the leading cause of BCNE. We provide a much-needed discussion on this topic.

Optic Neuritis and Vertebral Osteomyelitis: An Uncommon Presentation of Cat-Scratch Disease

In cat-scratch disease (CSD), hematogenous spread may result in atypical presentations. Ocular manifestations develop in a minority of patients, with treatment being important in reducing long-term visual sequelae. Bone infection is rare. We present the case of a 52-year-old woman, with close contact with cats, reporting acute unilateral blurred vision and presenting papilledema, optic disc pallor, and peripapillary hemorrhage. Etiologic study of optic neuritis revealed an elevated positive Bartonella IgG; hence, treatment for CSD with doxycycline plus rifampin and corticosteroids was started. Concomitant lumbar pain of increasing intensity warranted magnetic resonance imaging, which revealed L3-L4 vertebral osteomyelitis with spondylodiscitis. Given the temporal link with CSD diagnosis and the significant clinical improvement since its treatment was started, an etiologic link was presumed and antibiotics were prolonged. This case stands out for the presence of distinct atypical CSD manifestations in the same patient. Further studies are needed to determine the optimal treatment for rare manifestations, particularly bone infection.

BARTONELLA HENSELAE -ASSOCIATED OPTIC NEUROPATHY PRESENTING AS A CENTRAL SCOTOMA IN THE ABSENCE OF OVERT PAPILLITIS: A MULTIMODAL IMAGING STUDY

BACKGROUND/PURPOSE

The purpose of this report was to describe the use of multimodal imaging to establish the diagnosis of Bartonella henselae -associated optic neuropathy in a patient who presented with a central scotoma without overt evidence of optic nerve involvement.

METHODS

This was a case report. Main outcome measures included clinical, optical coherence tomography, and fluorescein angiography findings.

OBSERVATIONS

A 72-year-old woman presented with a 3-day history of central scotoma in the left eye. Her examination was remarkable for faint exudation in the nasal macula of the left eye but was otherwise normal for her age. Spectral domain optical coherence tomography of the macula revealed mild thickening of the papillomacular bundle with scattered small cystoid spaces and several intraretinal exudates, none of which were visible clinically. Fluorescein angiography revealed localized leakage of the inferotemporal optic disc. When prompted, the patient recalled being scratched multiple times by her two pet kittens. Serial testing showed rising anti- B. henselae ( B. henselae ) immunoglobulin G antibody titers to 1:1,280, confirming the suspected diagnosis of B. henselae -associated optic neuropathy.

CONCLUSION

Bartonella -associated optic nerve involvement can occur without overt evidence of optic disc swelling. Multimodal imaging can be used to suggest the diagnosis and support appropriate serologic testing.

Cat Scratch Disease: An Unusual Case of Right Inguinal Lymphadenitis Due to Bartonella henselae

Cat scratch disease (CSD) is caused by a bacterial infection due to Bartonella henselae and is associated with young cats and kittens. CSD commonly occurs as regional lymphadenitis in the setting of subacute regional lymphadenopathy predominantly in children and young adults. The prognosis for immunocompetent patients is favorable with complete recovery, however, immunocompromised adults can progress to life-threatening complications such as neuroretinitis, osteomyelitis, and bacillary angiomatosis. B. henselae is transmitted from cats to humans through scratching or biting when located on the cat's claws or oral cavity. In 1% of diagnosed cases, patients developed this disease without ever receiving an animal scratch.  We present a case of a 29-year-old immunocompetent male developing severe right inguinal pain with concern for an incarcerated inguinal hernia. He reported exposure to a vaccinated six-month-old kitten but denied any recent scratches or bites. His infectious workup revealed right inguinal lymphadenitis on CT imaging and subsequent lymph node biopsy confirmed a diagnosis of CSD. He was treated with a short course of oral doxycycline for CSD and opioids for pain management. This case illustrates the importance of thorough complete history and physical taking even in immunocompetent patients and early recognition with prompt targeted treatment of Bartonella lymphadenitis to prevent unfavorable outcomes.

"Let the Cat Out of the Heart": Clinical Characteristics of Patients Presenting With Blood Culture-Negative Endocarditis Due to Bartonella Species

Patients with blood culture-negative endocarditis due to Bartonella infection frequently presented with fever, cytopenias, kidney failure, and positive PR3-ANCA. Bartonella IgG titers were variable. Patients commonly underwent surgery with overall low mortality.

Bartonella spp. Infections Identified by Molecular Methods, United States

Molecular methods can enable rapid identification of Bartonella spp. infections, which are difficult to diagnose by using culture or serology. We analyzed clinical test results of PCR that targeted bacterial 16S rRNA hypervariable V1-V2 regions only or in parallel with PCR of Bartonella-specific ribC gene. We identified 430 clinical specimens infected with Bartonella spp. from 420 patients in the United States. Median patient age was 37 (range 1-79) years; 62% were male. We identified B. henselae in 77%, B. quintana in 13%, B. clarridgeiae in 1%, B. vinsonii in 1%, and B. washoensis in 1% of specimens. B. quintana was detected in 83% of cardiac specimens; B. henselae was detected in 34% of lymph node specimens. We detected novel or uncommon Bartonella spp. in 9 patients. Molecular diagnostic testing can identify Bartonella spp. infections, including uncommon and undescribed species, and might be particularly useful for patients who have culture-negative endocarditis or lymphadenitis.

Cat-scratch disease: Experience in a tertiary care children's hospital

Introduction. Bartonella henselae is the etiologic agent in cat-scratch disease. It affects children and young adults. The clinical spectrum is wide; the most common clinical presentation is a solitary lymphadenopathy. The objective of this study was to analyze the epidemiology, clinical features, and course of this disease in a tertiary care hospital in Argentina. Population and methods. Retrospective, descriptive, and observational study conducted at a tertiary care pediatric hospital from January 1st , 2019 to June 30th, 2021. Children aged 0 to 16 years with compatible clinical signs and symptoms and positive serology were included. Results. A total of 150 patients were included; their mean age was 7.9 years ± 3.68. Of them, 68.7% reported having contact with cats. The most common reason for consultation was the presence of solitary lymphadenopathies (84.7%) in the head and neck. Febrile syndrome without source was the reason for consultation in 15.5% of cases, with a pathological abdominal ultrasound scan in 85.7%. IgM and IgG were positive in 88%. With the result of a positive serology test, 44% received antibiotic treatment. Protracted lymphadenopathy was the main reason for antibiotic treatment; the agent most commonly used was azithromycin (42.4%). Fourteen percent (n = 21) required hospitalization. Conclusions. Diagnosis is based on clinical suspicion, epidemiological history, and complementary testing. Its typical presentation is a solitary enlarged lymph node in the head and neck. Due to the high frequency of hepatosplenic involvement, an abdominal ultrasound scan would be indicated in children with fever.

Unilateral Focal Retinitis as an Initial Manifestation of Cat-Scratch Disease

We report on a case of focal retinitis as the initial manifestation of cat-scratch disease. A 56-year-old Hispanic woman presented for a routine follow-up examination. A fundus examination of the right eye revealed a white retinal lesion along the inferotemporal artery; this lesion was noted to have progressed after one week of observation. On further inquiry, the patient reported she had seven cats at home, some of which were less than six months old and had recently scratched her. She received empirical treatment for focal retinitis with azithromycin (500 mg daily) and valacyclovir (1 g three times daily), which would cover the most common parasitic, viral, and bacterial etiologies. She was lost to a follow-up examination. However, she continued the same dose of antibiotic and antiviral treatment. Upon her eventual follow-up, three months later, it was noted that the lesion had resolved. The initial work-up revealed that she was positive for Bartonella henselae IgM (1:20) and IgG (1:512), as well as for B. quintana IgG (1:256); however, she was negative for B.quintana IgM. At a four-month follow-up appointment, the B. henselae IgM was negative, the IgG had decreased from 1:512 to 1:64, and the B. quintana antibody test was negative for IgM and IgG, all of which are consistent with an adequately treated case of cat-scratch disease. Focal retinitis can be a rare initial manifestation of cat-scratch disease, which should be considered part of the differential diagnosis in cases of focal retinitis, especially in patients with a history of close contact with young cats. Additionally, oral azithromycin may be considered as a treatment for some cases of cat-scratch-associated focal retinitis.

Cat Scratch Disease with Generalized Bone Lesions in an Immunocompetent Child

A 9-year-old immunocompetent girl with prolonged fever for 1 month was suspected of having a malignancy because of generalized bone abnormalities identified by MRI. Histopathology of liver tissues indicated the diagnosis of cat-scratch disease (CSD). Results of NGS, immunofluorescence and immunochemical assay confirmed the causative agent was Bartonella henselae. Paediatricians should increase their awareness of CSD as a cause for bone lesions, except for malignancy.

Bartonella henselea Prosthetic Valve Endocarditis Mimicking Vasculitis: A Case Report With Literature Review

Description We present one of the first reported cases of Bartonella henselae prosthetic valve endocarditis, which mimicked p-antineutrophil cytoplasmic autoantibody (p-ANCA), an anti-proteinase 3 positive necrotizing glomerulonephritis caused by a cat scratch resulting in temporary dialysis. Documentation of such infections is necessary as zoonotic infections are becoming more prevalent with early identification essential for proper treatment. Although pauci-immune patterns are not a unique finding in bacterial endocarditis associated with glomerulonephritis, they are an atypical finding in Bartonella henselae endocarditis. Furthermore, p-ANCA-associated vasculitis can also be responsible for renal and cardiac disease. Because of the similar disease presentation of different etiologies (autoimmune and infectious), it can make the diagnosis much more challenging. Our patient's presentation is unique as there are no documented cases in the medical literature of Bartonella henselae resulting in temporary hemodialysis from previously healthy kidneys with recovery. Our case documents the success of early identification and appropriate treatment.

Posterior Segment Manifestations of Cat-scratch Disease: A Mini-review of the Clinical and Multi-modal Imaging Features

Bartonella henselae, an intracellular gram-negative bacillus, is usually transmitted from infected cats to humans by direct or indirect contact. The bacterium mainly infects erythrocytes and endothelial cells thereby leading to so called cat-scratch disease (CSD) and may present with various localised and/or systemic manifestations. The eye is the most commonly affected organ in disseminated CSD and ocular bartonellosis has been reported in 5-10% of CSD patients. The most well-known clinical feature of ocular bartonellosis is neuroretinitis but various sight-threatening posterior segment lesions involving the optic nerve, retinal vasculature, retinal and choroidal tissues may occur during the disease course. This mini-review aims to overview both the clinical and multi-modal imaging characteristics of posterior ocular segment manifestations of CSD.

[Hepato-splenic involvement, an unusual finding secondary to cat-scratch disease: a clinical case]

The infection by Bartonela henselae (BH), the cause of cat scratch disease, it could be asymptomatic or produce local and multisystem illness. The objective of this case report is to document that the hepato-splenic involvement is unusual in BH infection, and the treatment is discussed and individualized in each patient. This case is about an eleven-year girl who presented with findings in abdominal tomography and ultrasound of hepato-splenic abscesses, with later positive serology for BH. In this way, a bibliographic review is carried out to show the low prevalence and incidence of hepato-splenic involvement where the anamnesis and the physical examination are essential to make an early diagnosis and treatment.

Atypical Manifestations of Cat-Scratch Disease, United States, 2005-2014

Atypical manifestations that can be severe and difficult to diagnosis develop in 5%-20% of patients with cat-scratch disease. To clarify the epidemiology of atypical cat-scratch disease in the United States, we analyzed data from the 2005-2014 MarketScan national health insurance claims databases by using the International Classification of Diseases, 9th Revision, Clinical Modification, codes for cat-scratch disease and selected atypical manifestations: retinitis/neuroretinitis, conjunctivitis, neuritis, encephalitis, hepatosplenic disease, osteomyelitis, erythema nodosum, and endocarditis. Atypical cat-scratch disease accounted for 1.5% of all cases, resulting in an average annual incidence of 0.7 cases/100,000 population. Atypical cat-scratch disease was associated with increased risk for hospitalization (risk ratios 8.77, 95% CI 6.56-11.72) and occurred most often in female patients 10-14 years of age. Ocular (48.7%), hepatosplenic (24.6%), and neurologic (13.8%) manifestations were most common among patients. A more comprehensive understanding of atypical cat-scratch disease can improve patient diagnosis and potentially elucidate pathophysiology of the disease.

[Cat-scratch disease with multiple bone involvement]

Cat-scratch disease is produced by the bacterium Bartonella henselae, a gram-negative bacillus transmitted through cutaneous inoculation by a cat or dog's scratch or bite. It has a wide clinical spectrum, from a typical picture characterized by a regional lymphadenopathy near to the inoculation site to atypical pictures with systemic compromise. Bone compromise is infrequent, it represents around 0.2-0.5 % of the cases. We present a 3-year-old previously healthy patient, who was admitted with prolonged fever related to pain and movement limitation of the cervical spine. Diagnosis of cat-scratch disease with multiple bone involvement was reached.

Hemorrhage and Rupture of an Unusual Benign Liver Lesion in Pregnancy: A Case Report

Liver rupture in pregnancy is an acute condition with significant risk to the mother and fetus. It is known to occur with tumors such as hepatic adenoma, infective causes such as abscess, granulomatous diseases, and parasitic infections, and rarely spontaneously. Most of these conditions have overlapping clinicoradiological findings, almost always requiring histopathological confirmation. We report a case of a ruptured hepatic lesion, with an unusual diagnosis of Bartonella henselae infection causing cat-scratch disease, in a 24-year-old pregnant lady.

Exposure of client-owned cats to zoonotic vector-borne pathogens: Clinic-pathological alterations and infection risk analysis

Zoonotic Vector-Borne Diseases (VBDs) represent a relevant health issue for pets and humans. Italy is a major epidemiological hub for feline VBDs, because of suitable conditions for vector biology and disease transmission patterns. The present study investigated the exposure to major zoonotic arthropod-borne pathogens of cats in Italy, along with the evaluation of clinic-pathological features and a risk factor analysis. Out of 167 examined cats, 52 (31.1%) were seropositive for at least one vector-borne pathogen, being positivity for Bartonella henselae the most recorded (18%). Also, various cats seroreacted for Rickettsia felis (10.8%) and Rickettisa typhi (4.2%), Leishmania infantum (3%), Anaplasma phagocytophilum (2.4%) and Ehrlichia canis (2.4%). Forty-six cats were tested also for antibodies against D. immitis and two (4.3%) scored positive. The statistical analysis showed a positive association between flea infestation and seropositivity to B. henselae, other than an association between the administration of monthly ectoparasiticide treatments and seronegativity for Rickettsia spp.; seropositive cats were older than negative animals and the lifestyle (i.e. indoor vs outdoor) was not correlated with exposure to vector-borne pathogens. The majority of seropositive cats appeared clinically healthy or showed aspecific clinical signs. Around 80% of seropositive cats had one or more biochemical and/or complete blood count abnormalities. The present data confirm the endemicity of zoonotic feline VBDs in Italy and indicate that awareness on arthropod infections and transmitted pathogens should be kept high and possible implemented, towards the protection of animal and human health with adequate surveillance plans.

Bartonella henselae Endocarditis: An Usual Presentation of an Unusual Disease

Bartonella species are an emerging cause of culture-negative endocarditis with more cases being diagnosed now than 25 years ago when Bartonella quintana endocarditis was first described in a patient infected with human immunodeficiency virus (HIV). Despite the disease being increasingly reported, the exact epidemiological features are not clear, with prevalence rates ranging between 2% and 10% of all cases of culture-negative endocarditis. Moreover, the mortality rate is still high, presumably because of the subacute nature and relative rareness of the disease. Bartonella endocarditis occurs more often in men, and previous valvular surgery is a major risk factor. There is insufficient data to guide definitive treatment due to the paucity of literature. A previous study demonstrated that effective antibiotic therapy for Bartonella endocarditis should include an aminoglycoside prescribed for a minimum of 2 weeks. However, the treatment strategy is a matter of expert opinion.

Characterization of Clinical Isolates of Bartonella henselae Strains, South Korea

Bartonella henselae, a gram-negative bacterium, is a common causative agent of zoonotic infections. We report 5 culture-proven cases of B. henselae infection in South Korea. By alignment of the 16S rRNA sequences and multilocus sequencing typing analysis, we identified all isolates as B. henselae Houston-1 strain, which belongs to sequence type 1.

Transverse Myelitis and Guillain-Barré Syndrome Associated with Cat-Scratch Disease, Texas, USA, 2011

We describe a case of coexisting transverse myelitis and Guillain-Barré syndrome related to infection with Bartonella henselae proteobacterium and review similar serology-proven cases. B. henselae infection might be emerging as a cause of myelitis and Guillain-Barré syndrome and should be considered as an etiologic factor in patients with such clinical presentations.

Bartonella henselae infection presenting as cervical spine osteomyelitis: case report

Bartonella henselae is a gram-negative bacillus implicated in cat-scratch disease. Cat-scratch disease is usually self-limiting and results in local lymphadenopathy. In rare circumstances, patients may develop endocarditis, neuroretinitis, or osteomyelitis. Osteomyelitis of the cervical spine is exceedingly rare, especially in the pediatric population, and to date there have been only 4 previously reported cases of cervical spine osteomyelitis caused by B. henselae, all of which were treated surgically. In this article, the authors report the case of a 7-year-old boy who presented with neck swelling and was found to have a C2-4 paravertebral B. henselae abscess with osteomyelitis of C-3 and epidural extension. To the authors' knowledge, this represents the first case in the literature of a cervical spine B. henselae infection managed conservatively.

Cat-scratch disease: ocular manifestations and treatment outcome

PURPOSE

To characterize cat-scratch disease (CSD) ocular manifestations and visual outcome and evaluate the effect of systemic antibiotics and corticosteroids on final visual acuity (VA).

METHODS

Multicentre retrospective cohort study. Medical records of 86 patients with ocular disease (107 eyes) of 3222 patients identified in a national CSD surveillance study were reviewed.

RESULTS

Mean age was 35.1 ± 14.2 years. Median follow-up was 20 weeks (range 1-806 weeks). Of 94/107 (88%) eyes with swollen disc, 60 (64%) had neuroretinitis at presentation, 14 (15%) developed neuroretinitis during follow-up, and 20 (21%) were diagnosed with inflammatory disc oedema. Optic nerve head lesion, uveitis, optic neuropathy and retinal vessel occlusion were found in 43 (40%), 38 (36%), 34 (33%) and 8 (7%) eyes, respectively. Good VA (better than 20/40), moderate vision loss (20/40-20/200) and severe vision loss (worse than 20/200) were found in 26/79 (33%), 35/79 (44%) and 18/79 (23%) eyes at baseline and in 63/79 (80%), 11/79 (14%) and 5/79 (6%) eyes at final follow-up, respectively (p < 0.001). Significant VA improvement (defined as improvement of ≥3 Snellen lines at final follow-up compared to baseline) occurred in 12/24 (50%) eyes treated with antibiotics compared with 14/16 (88%) eyes treated with antibiotics and corticosteroids (p = 0.02). Multivariate logistic regression was suggestive of the same association (odds ratio 7.0; 95% CI 1.3-37.7; p = 0.024).

CONCLUSION

Optic nerve head lesion is a common and unique manifestation of ocular CSD. Most patients improved and had final good VA. Combined antibiotics and corticosteroid treatment was associated with a better visual outcome.

Bartonella-Associated Transverse Myelitis

Each year in the United States, 500 patients are hospitalized for cat-scratch disease, caused by Bartonella henselae infection. We report a case of rare but serious neurologic B. henselae infection. When typical features of cat-scratch disease occur with neurologic findings, Bartonella infection should be suspected and diagnostic testing should be performed.

Lymphadenitis associated with cat-scratch disease simulating a neoplasm: Imaging findings with histopathological associations

The lymphadenitis associated with cat-scratch disease (CSD) is often confused with neoplasms by a number of radiologists and clinicians, and consequently, unnecessary invasive procedures or surgeries are performed. In the present study, the contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) findings of 10 patients (6 men and 4 women) with clinically and pathologically confirmed lymphadenitis associated with CSD were retrospectively analyzed (CT in 3 patients, MRI in 6 patients, and CT and MRI in 1 patient) at The Second Affiliated Hospital of Zhejiang University School of Medicine (Hangzhou, China) between January 2007 and November 2014. As a result, 17 enlarged lymph nodes were identified in 10 cases. The 5 nodes identified by CT scan exhibited relatively inhomogeneous isodensity to muscle, with patchy low density in the center. All 14 nodes identified by MRI scan exhibited homogeneous or heterogeneous isointensity to muscle or slightly increased intensity compared with that of muscle on T1-weighted images (T1WI), and homogeneous or heterogeneous hyperintensity on fat-suppressed T2WI. Following enhancement, all 17 enlarged lymph nodes associated with CSD demonstrated the following 3 different enhancement patterns: Moderate homogeneous enhancement (n=8), which was associated with histologically identified early disease stage; marked heterogeneous enhancement with no enhancement of the necrotic areas (n=4), and heterogeneous enhancement with progressively ‘spoke-wheel-like’ (defined as radiating enhancement from the center) enhancement of the patchy low-density area (n=1), which was associated with histologically identified intermediate disease stage; and astral low-density/hypointensity with marked enhancement (n=2) or a ‘rose flower’ sign (n=2), which was associated with histologically identified late disease stage. We hypothesized that the CT and MRI results of lymphadenitis in CSD may be associated with the pathological features. It may be suggested that the diagnosis of CSD may be formed when considering the characteristic CT and MRI features of astral low-density/hypointensity with marked enhancement or a ‘rose flower’ sign (defined as marginal petaloid enhancement) in the late disease stage, or the MRI results of homogeneous, moderate enhancement in the early disease stage, or the CT/MRI data of heterogeneous enhancement with non-enhancing area in the center in the intermediate disease stage, in solitary or multiple enlarged lymph nodes associated with general subcutaneous edema in the vicinity of the nodes on CT/MRI and with a history of cat exposure.

Depressiveness and Neuroticism in Bartonella Seropositive and Seronegative Subjects-Preregistered Case-Controls Study

Several recent studies have demonstrated the association of cat-related injuries with major depression and with depressiveness in the general population. It was suggested that cat-scratch disease, the infection with the bacterium Bartonella henselae, can be responsible for the observed association. However, no direct evidence for the role of the Bartonella infection in this association has been published until now. In this preregistered case-controls study performed on 250 healthy subjects tested earlier for the presence of anti-Toxoplasma IgG antibodies, we searched for the positive association between presence of anamnestic anti-Bartonella IgG antibodies and depressiveness measured with Beck II inventory, depression subscale of neuroticism measured with N-70 questionnaire, and self-reported health problems. We found that that Bartonella seropositivity was positively correlated with Beck depression only in Toxoplasma-seronegative men and negatively correlated with health in Toxoplasma-seronegative women. Bartonella seropositivity expressed protective effects against Toxoplasma seropositivity-associated increased neuroticism in men while Toxoplasma-seropositivity expressed protective effects against Bartonella seropositivity-associated health problems in women. A comparison of the patterns of association of mental and physical health problems with Bartonella seropositivity and with reported cat-related injury suggests that different factor, possibly infection with different pathogen transmitted by cat related-injuries than the B. henselae, is responsible for the observed association of cat related-injuries with depressiveness and major depression. The existence of complex interactions between Bartonella seropositivity, Toxoplasma seropositivity, and sex also suggest that the effect of symbionts on the host's phenotype must by always studied in the context of other infections, and separately for men and women.

Corticosteroid Treatment for Prolonged Fever in Hepatosplenic Cat-Scratch Disease: A Case Study

Hepatosplenic cat-scratch disease (CSD) may cause prolonged fever. We present the case of a 4-year-old boy with confirmed hepatosplenic CSD with fever lasting 3 months despite use of multiple different antimicrobial agents. The patient became afebrile soon after corticosteroid therapy was started. Our case indicates corticosteroids may be useful in patients with hepatosplenic CSD and prolonged fever.

The crystal structure of dihydrodipicolinate reductase from the human-pathogenic bacterium Bartonella henselae strain Houston-1 at 2.3 Å resolution

In bacteria, the second committed step in the diaminopimelate/lysine anabolic pathways is catalyzed by the enzyme dihydrodipicolinate reductase (DapB). DapB catalyzes the reduction of dihydrodipicolinate to yield tetrahydrodipicolinate. Here, the cloning, expression, purification, crystallization and X-ray diffraction analysis of DapB from the human-pathogenic bacterium Bartonella henselae, the causative bacterium of cat-scratch disease, are reported. Protein crystals were grown in conditions consisting of 5%(w/v) PEG 4000, 200 mM sodium acetate, 100 mM sodium citrate tribasic pH 5.5 and were shown to diffract to ∼2.3 Å resolution. They belonged to space group P4322, with unit-cell parameters a = 109.38, b = 109.38, c = 176.95 Å. Rr.i.m. was 0.11, Rwork was 0.177 and Rfree was 0.208. The three-dimensional structural features of the enzymes show that DapB from B. henselae is a tetramer consisting of four identical polypeptides. In addition, the substrate NADP+ was found to be bound to one monomer, which resulted in a closed conformational change in the N-terminal domain.

Retinal artery occlusion due to Bartonella henselae infection: a case series

PURPOSE

To report a case series of six patients suffering from branch retinal artery occlusion due to Bartonella henselae infection, in order to raise awareness to this etiology in the differential diagnosis of retinal artery occlusion.

METHODS

A retrospective case series of patients with branch retinal artery occlusion due to ocular cat scratch disease who presented at four tertiary medical centers in Israel, Turkey and Saudi Arabia between the years 2008-2014. Data retrieved from the medical records included demographic data, exposure, complaints, visual acuity, clinical findings and imaging, laboratory assessment, treatment, disease course and visual outcome.

RESULTS

The study group consisted of six patients who presented with branch retinal artery occlusion with or without neuroretinitis. One patient had multiple artery occlusions. Diagnosis of cat scratch disease was established based on positive serology and accompanying systemic symptoms, after ruling out other causes of retinal artery occlusion. Treatment included various regimens of antibiotics and systemic steroids. Visual outcome depended upon the obstructed artery.

CONCLUSION

Cat scratch disease may cause retinal artery occlusion in infected patients, leaving them with a permanent visual field defect. When retinal artery occlusion occurs as an early sign of the disease, prompt recognition may prevent further events. Thorough history and relevant tests may be of great value.

Cloning, expression, purification, crystallization and X-ray diffraction analysis of dihydrodipicolinate synthase from the human pathogenic bacterium Bartonella henselae strain Houston-1 at 2.1 Å resolution

The enzyme dihydrodipicolinate synthase catalyzes the committed step in the synthesis of diaminopimelate and lysine to facilitate peptidoglycan and protein synthesis. Dihydrodipicolinate synthase catalyzes the condensation of L-aspartate 4-semialdehyde and pyruvate to synthesize L-2,3-dihydrodipicolinate. Here, the cloning, expression, purification, crystallization and X-ray diffraction analysis of dihydrodipicolinate synthase from the pathogenic bacterium Bartonella henselae, the causative bacterium of cat-scratch disease, are presented. Protein crystals were grown in conditions consisting of 20%(w/v) PEG 4000, 100 mM sodium citrate tribasic pH 5.5 and were shown to diffract to ∼2.10 Å resolution. They belonged to space group P212121, with unit-cell parameters a = 79.96, b = 106.33, c = 136.25 Å. The final R values were Rr.i.m. = 0.098, Rwork = 0.183, Rfree = 0.233.

Cat-scratch disease with severe pleuritis in a 6-year-old girl

We present the case of a 6-year-old girl with cat-scratch disease (CSD), who developed severe pleuritis without lymphadenitis. Bartonella henselae DNA was detected on real-time polymerase chain reaction (PCR) analysis of whole blood. This is the first report of CSD diagnosed on real-time PCR using whole blood.

Touch not the cat bot a glove*: ANCA-positive pauci-immune necrotizing glomerulonephritis secondary to Bartonella henselae

A 36-year-old male presented with a secondary, but anti-neutrophil cytoplasmic antibody (ANCA) (proteinase-3) positive, vasculitis with renal insufficiency due to a pauci-immune necrotizing glomerulonephritis. An infective process was initially excluded by blood cultures and an echocardiogram prior to immunosuppression. The patient's condition failed to improve and re-evaluation confirmed infective endocarditis requiring valve replacement. Subsequent tissue cultures identified Bartonella henselae. Antibiotic treatment led to full resolution of physical, biochemical and immunological markers. This is the first case of B. henselae endocarditis-associated ANCA positivity with a pauci-immune glomerulonephritis. It demonstrates the importance of revisiting standard investigations in patients not improving expectantly on conventional therapy.

Cat-scratch disease in adult hospitalized for prolonged-Fever associated with multiple lymphadenopathies and weight loss

We report a 19-year-old patient with a Cat-scratch disease presenting three months continuous alteration of the general condition, including prolonged-fever, anorexia, asthenia, weight loss associated with adenitis and multiple thoracic-abdominal adenopathies, leukocytosis with neutrophil polynuclear predominance, and increased of C-reactive protein. The serologies of toxoplasmosis, infectious mononucleosis, human immunodeficiency virus, Brucellosis, Bartonellosis and the tuberculosis research by tuberculin reaction test and Ziehl acid-alcohol resistant bacilli direct examination were negatives. The cytomegalovirus and Epstein-Barr virus serologies were positives only for immunoglobulin-G. The Bartonella henselae diagnosis was made with the analysis of histopathological specimens. The clinical and biological symptoms regressed following eight weeks of azithromycin's treatment.

According to this observation, the cat-scratch disease should be considered in differential diagnosis of patients presenting prolonged-fever associated with multiple lymphadenopathies and weight loss. The azithromycin would be an alternative therapeutic issue for this pathology in case of confirmed efficacy by studies in a large patient population.

Small Indian mongooses and masked palm civets serve as new reservoirs of Bartonella henselae and potential sources of infection for humans

The prevalence and genetic properties of Bartonella species were investigated in small Indian mongooses and masked palm civets in Japan. Bartonella henselae, the causative agent of cat-scratch disease (CSD) was isolated from 15.9% (10/63) of the mongooses and 2.0% (1/50) of the masked palm civets, respectively. The bacteraemic level ranged from 3.0 × 10¹ to 8.9 × 10³ CFU/mL in mongooses and was 7.0 × 10³ CFU/mL in the masked palm civet. Multispacer typing (MST) analysis based on nine intergenic spacers resulted in the detection of five MST genotypes (MSTs 8, 14, 37, 58 and 59) for the isolates, which grouped in lineage 1 with MST genotypes of isolates from all CSD patients and most of the cats in Japan. It was also found that MST14 from the mongoose strains was the predominant genotype of cat and human strains. This is the first report on the isolation of B. henselae from small Indian mongooses and masked palm civets. The data obtained in the present study suggest that these animals serve as new reservoirs for B. henselae, and may play a role as potential sources of human infection.

Cat-scratch disease in Crete: an update

There are few epidemiological and clinical studies about the presence of cat scratch disease (CSD) on the island of Crete. The objective of this study was to analyze a large number of patients with suspected CSD to define the frequency of Bartonella infections in Crete. From January 2005 to October 2008, we studied patients with suspected CSD from hospitals in Crete. Sera of the referred patients were tested by immunofluorescence assay (IFA). For some patients, we also received lymph nodes and blood samples that we tested for the presence of Bartonella henselae by molecular assays. Overall, we tested 507 serum samples and we found 56 (11%) cases of CSD. PCR assay was positive for 2 patients; one had a B. henselae positive lymph node and the other a positive whole blood sample. Significantly more CSD cases (62.5%, 35 of 56) were reported in children than in infants and adults (P<0.05). Moreover, we identified that most cases of CSD occurred between May and September (P=0.002) and December and January. CSD is prevalent in Crete and is mostly associated with an increase in outdoor activity.

Acute, subacute, and chronic cervical lymphadenitis in children

Lymphadenopathy refers to any disease process involving lymph nodes that are abnormal in size and consistency. Lymphadenitis specifically refers to lymphadenopathies that are caused by inflammatory processes. Cervical lymphadenopathy is a common problem in the pediatric age group and is largely inflammatory and infectious in etiology. Although most patients are treated successfully by their primary care physician, surgical consultation is frequently required for patients who fail to respond to initial therapy or for those in whom there is an index of suspicion for a neoplastic process. This article addresses current approaches to the diagnosis and management of cervical lymphadenitis in children.

Detection of bartonella henselae DNA by polymerase chain reaction in a patient with cat scratch disease: a case report

We report a case of cat scratch disease caused by Bartonella henselae in Korea. A 25-yr-old woman developed left cervical lymphadenopathy with history of contact with a dog. The cervical lymphadenopathy persisted for 1 month and resolved gradually and spontaneously. Serologic test was not done during the acute stage of the disease. Immunofluorescent antibody test performed during the convalescent stage was positive for B. henselae. To confirm B. henselae infection, polymerase chain reaction (PCR) analysis using aspirates of cervical lymph node was performed and the presence of B. henselae DNA was demonstrated. This is the first reported case of cat scratch disease in Korea confirmed by PCR for B. henselae DNA.

Cat-Scratch Disease and Magnetic Resonance Imaging: 2 Case Reports

We report 2 cases of cat-scratch disease that had similar characteristic magnetic resonance images. Although this technique is not specific for the disease, we believe that it might be useful for diagnosis of this condition in atypical cases.