Skin manifestations of Bartonella infections

Bartonella spp. infection in people with Mild Cognitive Impairment: A pilot study

Mild Cognitive Impairment (MCI) is a neurological disorder at the transition between normal cognitive decline and dementia. Despite the potential role of neuroinflammation in the pathogenesis of MCI, infectious triggers remain mostly unknown. Infection with Bartonella spp., a zoonotic bacterium, has recently been associated with diffuse neurological and psychiatric symptoms. Given the preferential endothelial localization of Bartonella spp. and the role of vascular changes in neurocognitive decline, we hypothesized that there is an association between Bartonella spp. infection and pathologically accelerated decline in cognitive function in aging. To test this hypothesis, we collected serological and molecular markers of past and present Bartonella spp. infection in a sample of older people with and without MCI. Samples were processed in a blinded way to exclude laboratory biases. Contrary to our hypothesis, people with MCI were not more likely than people without MCI to have an active Bartonella spp. infection as measured by droplet digital PCR (p = 0.735) and quantitative PCR (p = 1). In addition, there was no significant difference in positive serological results between cases and controls (p = 0.461). Overall, higher-than-expected active Bartonella spp. infection (37% by ddPCR) and seroreactivity (71% by indirect fluorescent antibody assay) were found in people without MCI. Conclusions require caution, as our study was limited by the small number of cases with MCI. Overall, our results identified a higher than previously recognized rate of exposure and infection with Bartonella spp. in this older study population but does not support a specific role for such infection in MCI.

Investigation of Transovarial Transmission of Bartonella henselae in Rhipicephalus sanguineus sensu lato Ticks Using Artificial Feeding

Bartonella henselae is a slow-growing, Gram-negative bacterium that causes cat scratch disease in humans. A transstadial transmission of the bacteria from larvae to nymphs of Rhipicephalus sanguineus sensu lato (s.l.) ticks, suspected to be a potential vector of the bacteria, has been previously demonstrated. The present study aims to investigate transovarial transmission of B. henselae from R. sanguineus s.l. adults to their instars. Adult ticks (25 males and 25 females) were fed through an artificial feeding system on B. henselae-infected goat blood for 14 days, and 300 larvae derived from the experimentally B. henselae-infected females were fed on noninfected goat blood for 7 days. Nested PCR and culture were used to detect and isolate B. henselae in ticks and blood samples. Bartonella henselae DNA was detected in midguts, salivary glands, and carcasses of the semi-engorged adults and pooled tick feces (during feeding and post-feeding periods). After the oviposition period, B. henselae DNA was detected in salivary glands of females (33.3%), but not in pooled eggs or larvae derived from the infected females. However, B. henselae DNA was detected by nested PCR from the blood sample during larval feeding, while no viable B. henselae was isolated by culture. According to our findings, following infected blood meal, B. henselae could remain in the tick midguts, move to other tissues including salivary glands, and then be shed through tick feces with limited persistency. The presence of bacterial DNA in the blood during larval feeding shows the possibility of transovarial transmission of B. henselae in R. sanguineus s.l. ticks.

Transmission of Bartonella henselae within Rhipicephalus sanguineus: Data on the Potential Vector Role of the Tick

Bartonella henselae is a fastidious intraerythrocytic, gram-negative bacteria that causes cat scratch disease in humans. Ixodes ricinus has been confirmed to be a competent vector of B. henselae, and some indirect evidences from clinical cases and epidemiological studies also suggested that some other tick species, including Rhipicephalus sanguineus, may transmit the bacteria. B. henselae has been detected in R. sanguineus but no experimental investigations have been performed to evaluate the vector competency of this tick species regarding B. henselae transmission. To this end, this work aimed to assess the transstadial transmission of B. henselae between larvae and nymphs of R. sanguineus as well as transmission by nymphs infected at the larval stage. Four hundred B. henselae negative larvae were fed with B. henselae-infected blood by using an artificial membrane feeding system. After five days of feeding, B. henselae was detected by PCR in 57.1% (8/14) of engorged larval pools, 66.7% (4/6) of semi-engorged larval pools, and 66.7% (2/3) of larval feces pools. After molting, B. henselae DNA was also detected in 10% (1/10) of nymph pools, but not in tick feces. After a pre-fed step of nymphs infected at the larval stage on non-infected blood meal, B. henselae was detected by PCR in blood sample from the feeder, but no Bartonella colonies could be obtained from culture. These findings showed that B. henselae could be transstadial transmitted from R. sanguineus larvae to nymphs, and also suggest that these nymphs may retransmitted the bacteria through the saliva during their blood meal. This is the first study that validated the artificial membrane feeding system for maintaining R. sanguineus tick colony. It shows the possibility of transstadial transmission of B. henselae from R. sanguineus larvae to nymphs.

B. henselae is gram-negative bacteria that infects red blood cells of humans and companion animals and causes cat scratch disease in humans. Ticks were considered to be potential vectors of B. henselae for a long time until it was finally experimentally demonstrated for Ixodes ricinus. Since then, no evidence on B. henselae transmission by other tick species was reported. This study was performed 1) to validate the use of artificial membrane system to feed and infect R. sanguineus ticks and 2) to determine the possibility of B. henselae transmission by R. sanguineus, a world-widely distributed ticks. Our results show that the artificial membrane feeding system can be used to maintain R. sanguineus colony in the laboratory, and that B. henselae can be acquired by R. sanguineus during a blood meal on artificial membrane feeding system and can be transmitted from larvae to nymphs that were able to inject bacterial DNA to blood during a new blood meal. However, further investigations are still needed to confirm the viability of bacteria transmitted to blood by nymphs infected at the larval stage in order to validate B. henselae transmission by R. sanguineus.

Cutaneous manifestations of bartonellosis

Bartonellosis are diseases caused by any kind of Bartonella species. The infection manifests as asymptomatic bacteremia to potentially fatal disorders. Many species are pathogenic to humans, but three are responsible for most clinical symptoms: Bartonella bacilliformis, Bartonella quintana, and Bartonella henselae. Peruvian wart, caused by B. bacilliformis, may be indistinguishable from bacillary angiomatosis caused by the other two species. Other cutaneous manifestations include maculo-papular rash in trench fever, papules or nodules in cat scratch disease, and vasculitis (often associated with endocarditis). In addition, febrile morbilliform rash, purpura, urticaria, erythema nodosum, erythema multiforme, erythema marginatus, granuloma annularis, leukocytoclastic vasculitis, granulomatous reactions, and angioproliferative reactions may occur. Considering the broad spectrum of infection and the potential complications associated with Bartonella spp., the infection should be considered by physicians more frequently among the differential diagnoses of idiopathic conditions. Health professionals and researchers often neglected this diseases.

Collagen Anomalies as Clues for Diagnosis: Part 1

BACKGROUND

Collagen is the most abundant protein in the body and the main structural component of the skin.

OBJECTIVE

To provide a review of the histopathology of collagen alterations and to propose a classification with the most important types of collagen anomalies in dermatopathology. The authors describe some of the main morphological clues of collagen anomalies for specific diagnosis of some cutaneous inflammatory and neoplastic conditions.

METHODS

The authors review histopathologic collagen anomalies, concerning both morphology and disposition in some inflammatory and neoplastic cutaneous conditions, and they review previous terminology and proposed a classification of the most important types of collagen anomalies that can be seen in dermatopathological practice.

RESULTS

Collagen anomalies in skin can be classified into lamellar fibrosis, sclerosis, and "balls" and "rings" of collagen. Lamellar fibrosis presents as long and thin collagen bundles forming a delicate network, which can be disposed in a parallel pattern, onion-bulb-like pattern, and storiform pattern. Sclerosis is characterized by large, thick, and eosinophilic bundles of collagen, which may present as a homogenous-diffuse pattern or as individual thick bundles of collagen with few or abundant number of fibroblasts between them. Finally, the authors propose the terms "balls" and "rings" of collagen. The term "balls" of collagen stands for thick, homogenous, eosinophilic, globular collagen bundles, with no distinguishable individual composing fibers, which include the floating sign and the free-floating sign. The term "rings" of collagen is characterized by sclerotic collagen arranged in a homogenous rimming pattern around vessels without independent fibers in its composition.

CONCLUSIONS

Collagen anomalies may be important clues to establish specific clues for specific diagnoses in dermatopathology.

Cat-scratch disease: a wide spectrum of clinical pictures

The aim of this review is to present an emerging zoonotic disease caused by Bartonella henselae. The wide spectrum of diseases connected with these bacteria varies from asymptomatic cases, to skin inflammation, fever of unknown origin, lymphadenopathy, eye disorders, encephalitis and endocarditis. The reservoirs of B. henselae are domestic animals like cats, guinea pigs, rabbits and occasionally dogs. Diagnosis is most often based on a history of exposure to cats and a serologic test with high titres of the immunoglobulin G antibody to B. henselae. Most cases of cat-scratch disease are self-limited and do not require antibiotic treatment. If an antibiotic is chosen, however, azithromycin has been shown to speed recovery.

Initial diagnosis of HIV/AIDS in a 56-year-old man with non-healing forearm lesion

A 56-year-old Hispanic man with no significant medical problems presented with a 2-month history of a non-healing right forearm lesion that progressed despite several courses of empiric antibiotics. The patient underwent incision and drainage. Warthin-Starry stain with immunohistochemistry testing diagnosed bacillary angiomatosis secondary to Bartonella quintana. Subsequently, the patient was diagnosed with HIV, with a CD4 count of 68 cells/mm(3), and a HIV viral load of 47, 914 copies/mL. The patient was treated with doxycycline and started on antiretroviral therapy. The lesion has resolved and he has had no recurrence after 16 months of treatment.

Spectrum of radiological manifestations of paediatric cat-scratch disease

Cat-scratch disease (CSD) is usually a self-limiting condition that may mimic more serious disorders due to its variable clinical and imaging presentations. Many cases are diagnosed throughout the United States annually, with the majority occurring in children and adolescents who have had contact with a cat, usually in the form of a scratch or bite. This manuscript will discuss the spectrum of radiologic manifestations of CSD emphasising key imaging findings of lymphadenopathy, hepatosplenic lesions, osteomyelitis, discitis, encephalitis, neuroretinitis and cranial neuritis.

Concomitant cat scratch disease and squamous cell carcinoma in a cardiac transplant

Cat scratch disease has been reported very rarely in cardiac transplant recipients. In a review of 1073 episodes of infection in 620 heart transplant patients over a 16 year period, only one case of infection secondary to Bartonella henselae was documented. Another case of hepatosplenic bacillary angiomatosis from B. henselae was reported 2 decades ago in a heart transplant recipient who had presented with fevers of unknown origin. Although the typical clinical manifestation is that of a skin lesion accompanied with lymphadenopathy, cat scratch disease may present with persistent fevers without a clinically overt infective focus in immunosuppressed individuals. Moreover, more than one disease process may coexist in immunocompromised hosts. While the lymphadenopathy in our patient was secondary to Cat scratch disease, interestingly, the adjacent skin lesion that was thought to represent unhealed site of inoculation of Bartonella was diagnosed as squamous cell carcinoma.

Intruders below the radar: molecular pathogenesis of Bartonella spp

Bartonella spp. are facultative intracellular pathogens that employ a unique stealth infection strategy comprising immune evasion and modulation, intimate interaction with nucleated cells, and intraerythrocytic persistence. Infections with Bartonella are ubiquitous among mammals, and many species can infect humans either as their natural host or incidentally as zoonotic pathogens. Upon inoculation into a naive host, the bartonellae first colonize a primary niche that is widely accepted to involve the manipulation of nucleated host cells, e.g., in the microvasculature. Consistently, in vitro research showed that Bartonella harbors an ample arsenal of virulence factors to modulate the response of such cells, gain entrance, and establish an intracellular niche. Subsequently, the bacteria are seeded into the bloodstream where they invade erythrocytes and give rise to a typically asymptomatic intraerythrocytic bacteremia. While this course of infection is characteristic for natural hosts, zoonotic infections or the infection of immunocompromised patients may alter the path of Bartonella and result in considerable morbidity. In this review we compile current knowledge on the molecular processes underlying both the infection strategy and pathogenesis of Bartonella and discuss their connection to the clinical presentation of human patients, which ranges from minor complaints to life-threatening disease.

[Inflammatory dermatoses]

The seven basic patterns of inflammatory dermatoses according to Ackerman can be applied to infectious dermatoses. However, it should be borne in mind that infection caused by one agent may induce differing patterns according to the stage of disease. Dermatophytosis and the arthropod reaction belong to perivascular dermatoses with spongiosis. Secondary syphilis and acrodermatitis chronica atrophicans regularly show a lichenoid infiltrate with interface dermatitis, whereas epidermal involvement is typically absent in erythema migrans, virus exanthema and bacillary angiomatosis. Lupus vulgaris, atypic mycobacteriosis, lepra, actinomycosis, cutaneous leishmaniosis and erysipelas belong to the nodular and diffuse dermatoses. In the group of vasculitides, septic vasculitis is induced by a biological agent, and the pattern of vesicular dermatitis is reflected by infections with herpes viruses, impetigo contagiosa and staphylococcal scalded-skin syndrome. Follicular dermatitis shows a pattern of furuncles and carbuncles which are mainly caused by bacteria or fungi.

Bartonella henselae in skin biopsy specimens of patients with cat-scratch disease

During the past 2 years, we identified live Bartonella henselae in the primary inoculation sites of 3 patients after a cat scratch. Although our data are preliminary, we report that a cutaneous swab of the skin lesion from a patient in the early stage of cat-scratch disease can be useful for diagnosis of the infection.

The Bartonella henselae VirB/Bep system interferes with vascular endothelial growth factor (VEGF) signalling in human vascular endothelial cells

The vasculotropic pathogen Bartonella henselae (Bh) intimately interacts with human endothelial cells (ECs) and subverts multiple cellular functions. Here we report that Bh specifically interferes with vascular endothelial growth factor (VEGF) signalling in ECs. Bh infection abrogated VEGF-induced proliferation and wound closure of EC monolayers as well as the capillary-like sprouting of EC spheroids. On the molecular level, Bh infection did not alter VEGF receptor 2 (VEGFR2) expression or cell surface localization, but impeded VEGF-stimulated phosphorylation of VEGFR2 at tyrosine(1175) . Consistently, we observed that Bh infection diminished downstream events of the tyrosine(1175) -dependent VEGFR2-signalling pathway leading to EC proliferation, i.e. phospholipase-Cγ activation, cytosolic calcium fluxes and mitogen-activated protein kinase ERK1/2 phosphorylation. Pervanadate treatment neutralized the inhibitory activity of Bh on VEGF signalling, suggesting that Bh infection may activate a phosphatase that alleviates VEGFR2 phosphorylation. Inhibition of VEGFR2 signalling by Bh infection was strictly dependent on a functional VirB type IV secretion system and thereby translocated Bep effector proteins. The data presented in this study underscore the role of the VirB/Bep system as important factor controlling EC proliferation in response to Bh infection; not only as previously reported by counter-acting an intrinsic bacterial mitogenic stimulus, but also by restricting the exogenous angiogenic stimulation by Bh-induced VEGF.

Skin diseases associated with Bartonella infection: facts and controversies

The genus Bartonella is composed of a series of species and subspecies. Ten of them are responsible for human infections. The best-identified diseases are cat scratch disease (B henselae and possibly B clarridgeiae), trench fever (B quintana), bacillary angiomatosis (B quintana and B henselae), and the spectrum of verruga peruana, Carrion disease, and Oroya fever (B bacilliformis). Controversies exist about the implication of a few other microorganisms being involved in these diseases. Several other conditions have been associated with the presence of Bartonella spp, but these observations await confirmation.

Atypical Adenopathy Associated With Cat Scratch Disease in a Chronically Ill Woman

Cat scratch disease is a relatively common bacterial infection caused by contact with infected feline saliva. This case demonstrates an unusual presentation of adenopathy involving the superficial subcutaneous tissue of the upper extremity. Because of the location, adenopathy was not the primary consideration. The ultimate cause was identified as cat scratch disease caused by the Bartonella henselae organism in a chronically ill woman.

Pestilence, persistence and pathogenicity: infection strategies of Bartonella

It has been nearly two decades since the discovery of Bartonella as an agent of bacillary angiomatosis in AIDS patients and persistent bacteremia and 'nonculturable' endocarditis in homeless people. Since that time, the number of Bartonella species identified has increased from one to 24, and 10 of these bacteria are associated with human disease. Although Bartonella is the only genus that infects human erythrocytes and triggers pathological angiogenesis in the vascular bed, the group remains understudied compared with most other bacterial pathogens. Numerous questions regarding Bartonella's molecular pathogenesis and epidemiology remain unanswered. Virtually every mammal harbors one or more Bartonella species and their transmission typically involves a hematophagous arthropod vector. However, many details regarding epidemiology and the public health threat imposed by these animal reservoirs is unclear. A handful of studies have shown that bartonellae are highly-adapted pathogens whose parasitic strategy has evolved to cause persistent infections of the host. To this end, virulence attributes of Bartonella include the subversion of host cells with effector molecules delivered via a type IV secretion system, induction of pathological angiogenesis through various means, including inhibition of apoptosis and activation of hypoxia-inducing factor 1, use of afimbrial adhesins that are orthologs of Yersinia adhesin A, incorporation of lipopolysaccharides with low endotoxic potency in the outer membrane, and several other virulence factors that help Bartonella infect and persist in erythrocytes and endothelial cells of the host circulatory system.

Distinct activities of Bartonella henselae type IV secretion effector proteins modulate capillary-like sprout formation

The zoonotic pathogen Bartonella henselae (Bh) can lead to vasoproliferative tumour lesions in the skin and inner organs known as bacillary angiomatosis and bacillary peliosis. The knowledge on the molecular and cellular mechanisms involved in this pathogen-triggered angiogenic process is confined by the lack of a suitable animal model and a physiologically relevant cell culture model of angiogenesis. Here we employed a three-dimensional in vitro angiogenesis assay of collagen gel-embedded endothelial cell (EC) spheroids to study the angiogenic properties of Bh. Spheroids generated from Bh-infected ECs displayed a high capacity to form sprouts, which represent capillary-like projections into the collagen gel. The VirB/VirD4 type IV secretion system and a subset of its translocated Bartonella effector proteins (Beps) were found to profoundly modulate this Bh-induced sprouting activity. BepA, known to protect ECs from apoptosis, strongly promoted sprout formation. In contrast, BepG, triggering cytoskeletal rearrangements, potently inhibited sprouting. Hence, the here established in vitro model of Bartonella- induced angiogenesis revealed distinct and opposing activities of type IV secretion system effector proteins, which together with a VirB/VirD4-independent effect may control the angiogenic activity of Bh during chronic infection of the vasculature.

Beyond cat scratch disease: widening spectrum of Bartonella henselae infection

Bartonella henselae was discovered a quarter of a century ago as the causative agent of cat scratch disease, a clinical entity described in the literature for more than half a century. As diagnostic techniques improve, our knowledge of the spectrum of clinical disease resulting from infection with Bartonella is expanding. This review summarizes current knowledge regarding the microbiology, clinical manifestations, diagnostic techniques, and treatment of B. henselae infection.

Bone marrow and skin granulomatosis in a patient with Bartonella infection

This report describes a case of granulomatous inflammation, involving the bone marrow and skin, due to Bartonella infection in an immunocompetent patient. The clinical presentation included prolonged fever, pancytopenia, rash and hepatitis. Bartonella infection should thus be added to the growing list of entities that produce marrow granulomas and fever.

The Expanded Spectrum of Bartonellosis in Children

Bartonella spp cause various clinical syndromes immunocompetent and immunocompromised hosts. Domestic cats are the natural reservoir, and vectors of B henselae. B henselae infection usually occurs early in childhood, is generally asymptomatic, and in most cases revolves spontaneously. It may, however, produce a wide spectrum of clinical symptoms, the most frequent feature being cat-scratch disease. Disseminated atypical B. henselae infection may follow cat-scratch disease alter a symptom-free period or may present de novo mimicking a wide range of clinical disorders. A careful clinical history researching an intimate contact with a kitten associated with a specific serology and an abdominal ultrasound for typical hepatosplenic involvement may follow a rapid and accurate diagnosis.

Cat scratch disease mimicking Richter's Syndrome in a patient with chronic lymphocytic leukemia

Richter's Syndrome is a highly refractory and usually fatal condition. It occurs as a result of transformation of chronic lymphocytic leukemia (CLL) or low grade lymphoma into highly aggressive lymphoma. Patients usually present with rapidly enlarging lymph nodes and systemic symptoms like night sweats, fever and weight loss. We are reporting a case of CLL presenting with similar symptoms. Initial suspicion of Richter's Syndrome proved wrong when lymph node biopsy did not reveal evidence of high grade lymphoma. Instead it showed findings consistent with cat scratch disease (CSD), later confirmed by serology. To our knowledge this is the first reported case of CSD in a patient with CLL.