Cat scratch disease, bacillary angiomatosis, and other infections due to Rochalimaea

A systematic review on antibiotic therapy of cutaneous bacillary angiomatosis not related to major immunocompromising conditions: from pathogenesis to treatment

BACKGROUND

Cutaneous bacillary angiomatosis (cBA) is a vascular proliferative disorder due to Bartonella spp. that mostly affects people living with HIV (PLWH), transplanted patients and those taking immunosuppressive drugs. Since cBA is mostly related to these major immunocompromising conditions (i.e., T-cell count impairment), it is considered rare in relatively immunocompetent patients and could be underdiagnosed in them. Moreover, antimicrobial treatment in this population has not been previously investigated.

METHODS

We searched the databases PubMed, Google Scholar, Scopus, OpenAIRE and ScienceDirect by screening articles whose title included the keywords "bacillary" AND "angiomatosis" and included case reports about patients not suffering from major immunocompromising conditions to provide insights about antibiotic treatments and their duration.

RESULTS

Twenty-two cases of cBA not related to major immunocompromising conditions were retrieved. Antibiotic treatment duration was shorter in patients with single cBA lesion than in patients with multiple lesions, including in most cases macrolides and tetracyclines.

CONCLUSIONS

cBA is an emerging manifestation of Bartonella spp. infection in people not suffering from major immunocompromising conditions. Until evidence-based guidelines are available, molecular tests together with severity and extension of the disease can be useful to personalize the type of treatment and its duration.

A case of hepatosplenic cat scratch disease with hemophagocytic lymphohistiocytosis

Cat scratch disease (CSD) is associated with Bartonella henselae (B. henselae) infection caused by cat scratches or bites. It typically presents with lymphadenitis and fever. However, there are atypical cases such as hepatosplenic CSD, which presents with specific lesions in the liver and spleen. Hemophagocytic lymphohistiocytosis (HLH) is a rare and severe multisystem disorder triggered by infections, cancers, or autoimmune diseases. We experienced a rare case of hepatosplenic CSD with HLH in a non-immunocompromised adult. A 78-year-old woman complained of fever and fatigue. Laboratory tests revealed anemia and liver dysfunction; abdominal contrast-enhanced computed tomography (CT) revealed splenomegaly and nodular hypodense areas in the spleen. In addition, the levels of ferritin and serum soluble IL-2R were markedly elevated, so clinical diagnosis of HLH was made. Positron emission tomography/CT revealed diffuse fluorodeoxyglucose uptake in the liver and spleen suggesting malignant lymphoma, while the pathological findings from liver biopsy suggested infectious diseases. Although she had no cat bites and scratches, she had many cats; therefore, serum B. henselae antibody titers were measured. The B. henselae IgG and IgM titer were 1:128 and 1:20; thus, she was diagnosed with hepatosplenic CSD. Patients with hepatosplenic nodular lesions and contact with cats should be considered for this disease.

The Clinical Profile of Cat-Scratch Disease’s Neuro-Ophthalmological Effects

Cat-scratch disease is an illness caused by Bartonella henselae that occurs as a result of contact with an infected kitten or dog, such as a bite or scratch. It is more prevalent in children and young adults, as well as immunocompromised individuals. There are limited publications examining the features of CSD in patients. As such, the purpose of this research was to assess the clinical neuro-ophthalmological consequences of CSD reported in the literature. Among the ophthalmologic disorders caused by cat-scratch disease in humans, Parinaud oculoglandular syndrome, uveitis, vitritis, retinitis, retinochoroiditis and optic neuritis are the most prevalent. The neurological disorders caused by cat-scratch disease in humans include encephalopathy, transverse myelitis, radiculitis, and cerebellar ataxia. The current review addresses the neuro-ophthalmological clinical manifestations of cat-scratch disease, as described in papers published over the last four decades (1980–2022). All the data gathered were obtained from PubMed, Medline and Google Scholar. The current descriptive review summarizes the most-often-encountered clinical symptomatology in instances of cat-scratch disease with neurological and ocular invasion. Thus, the purpose of this review is to increase knowledge of cat-scratch disease’s neuro-ophthalmological manifestations.

The Bartonella autotransporter BafA activates the host VEGF pathway to drive angiogenesis

Pathogenic bacteria of the genus Bartonella can induce vasoproliferative lesions during infection. The underlying mechanisms are unclear, but involve secretion of an unidentified mitogenic factor. Here, we use functional transposon-mutant screening in Bartonella henselae to identify such factor as a pro-angiogenic autotransporter, called BafA. The passenger domain of BafA induces cell proliferation, tube formation and sprouting of microvessels, and drives angiogenesis in mice. BafA interacts with vascular endothelial growth factor (VEGF) receptor-2 and activates the downstream signaling pathway, suggesting that BafA functions as a VEGF analog. A BafA homolog from a related pathogen, Bartonella quintana, is also functional. Our work unveils the mechanistic basis of vasoproliferative lesions observed in bartonellosis, and we propose BafA as a key pathogenic factor contributing to bacterial spread and host adaptation.

Pathogenic bacteria of the genus Bartonella can induce vasoproliferative lesions during infection. Here, Tsukamoto et al. show that this effect is caused by a secreted protein that induces cell proliferation and angiogenesis by acting as an analog of the host’s vascular endothelial growth factor (VEGF).

Splenorenal Manifestations of Bartonella henselae Infection in a Pediatric Patient

Bartonella henselae is a bacterium which can cause a wide range of clinical manifestations, ranging from fever of unknown origin to a potentially fatal endocarditis. We report a case of Bartonella henselae infection in a pediatric-aged patient following a scratch from a kitten. The patient initially presented with a prolonged fever of unknown origin which was unresponsive to antibiotic treatment. The patient was hospitalized with worsening fevers and night sweat. Subsequent ultrasound imaging demonstrated multiple hypoechoic foci within the spleen. A contrast-enhanced CT of the abdomen and pelvis was also obtained which showed hypoattenuating lesions in the spleen and bilateral kidneys. Bartonella henselae IgG and IgM titers were positive, consistent with an acute Bartonella henselae infection. The patient was discharged with a course of oral rifampin and trimethoprim-sulfamethoxazole, and all symptoms had resolved following two weeks of therapy.

Bacillary Angiomatosis in Immunocompetent Patient with Atypical Manifestations

Bacillary angiomatosis is an infectious disease caused by two Gram-negative bacilli; this disease usually affects immunosuppressed hosts with a history of cat scratch. We report a rare case of bacillary angiomatosis in an immunocompetent 26-year-old woman with no history of exposure to cats, and with atypical clinical features (very pruritic vascular papules and nodules with ulceration and hemorrhage on the right arm and fingers). She was successfully treated with clarithromycin for 3 months. Bacillary angiomatosis must be kept in mind in the differential diagnosis of any papules and nodules in cases of unknown etiology and also in immunocompetent patients and HIV-negative individual.

Clinicocytopathologic correlation in an atypical presentation of lymphadenopathy with review of literature

OBJECTIVES

To present a clinicocytopathologic correlation of an atypical case of cat scratch disease (CSD) involving retroperitoneal lymph nodes, with emphasis on communication between service teams for managing lymphadenopathy of unknown origin. We consider clinical and cytologic differential diagnoses and review the literature on atypical cases of CSD, with emphasis on abdominal presentation and cytologic findings.

METHODS

Clinical services met with the cytology service to review clinical and pathologic features. Literature was reviewed via PubMed search (Harbor-UCLA subscriptions). Immunohistochemistry and Steiner silver stains were performed by Harbor-UCLA Department of Pathology. Enzyme-linked immunosorbent assay IgG and IgM Bartonella henselae titers were carried out by Quest Nichols Institute.

RESULTS

Fine-needle aspirate Diff-Quik and Papanicolaou smears and H&E-stained cell block showed abundant histiocytes, monocytoid B cells, and numerous neutrophils associated with necrosis corresponding to a late stage of CSD infection. Silver stain was positive for clumps of pleomorphic organisms. IgM and IgG antibody titers were elevated.

CONCLUSIONS

The cytologic findings of CSD in an atypical abdominal presentation are similar to those of a classic presentation. Laboratory workup for atypical CSD should include at least two other modalities aside from cytomorphologic features. Close clinical and cytologic correlation avoided potentially unnecessary and harmful surgery and enabled timely treatment.

Bacillary angiomatosis presenting as a pyogenic granuloma of the hand in an otherwise apparently healthy patient

Bacillary angiomatosis is a rare opportunistic infection caused by the gram-negative bacteria Bartonella. The infection is strongly related to human immunodeficiency virus (HIV) infection, and hence, the diagnosis is usually considered based on the fact that the patient is HIV positive. We report on a case of bacillary angiomatosis presenting as a pyogenic granuloma of the hand in an otherwise apparently healthy man. The report is aimed to increase the awareness of hand surgeons that this serious disease may be the first clinical manifestation of HIV infection. The case also demonstrates that once the correct diagnosis is made, medical treatment alone may be sufficient to cure massive recurrent lesions.

Bartonella henselae infections in solid organ transplant recipients: report of 5 cases and review of the literature

Bartonella henselae is the causative agent of cat scratch disease and bacillary angiomatosis-peliosis. The spectrum of disease, diagnosis, and management of B. henselae infection in solid organ transplant recipients has not been well characterized. We identified 29 cases of solid organ transplant recipients who had Bartonella infection, 24 by a review of the English-language literature and 5 from our institution. Localized cat scratch disease was found in 8 patients (28%), and disseminated infection was found in 21 patients (72%). The mean time after transplantation to development of Bartonella infection among those with cat scratch disease was 5.6 ± 5.3 years, and among those with disseminated infection was 2.7 ± 2.4 years. Prominent clinical features included cat exposure in 26 patients (90%), fever in 27 patients (93%), lymphadenopathy in 12 patients (41%), and skin lesions in 7 patients (24%). Methods used in establishing the diagnosis of Bartonella infection included culture, polymerase chain reaction (PCR) assay, serologic assays, and histopathologic examination. Culture was positive in 2 of only 4 patients in whom this was performed, and PCR was positive in 12 of 14 patients (86%) in whom this test was performed. Serologic assays were positive in all 23 patients who were tested. Histopathologic examination of tissues in all 8 patients who had cat scratch disease revealed granulomatous inflammation in 4 (50%) and bacillary angiomatosis-peliosis in 2 (25%). Among the 15 patients who had disseminated infection and who had tissue examined, 8 (53%) had only granulomatous inflammation, 4 had only bacillary angiomatosis-peliosis (27%), and 2 had both granulomas and bacillary angiomatosis-peliosis (13%). A positive Warthin-Starry or Steiner stain was noted in 12 of 19 patients (63%) who had 1 of these stains performed. All 8 patients with cat scratch disease and 19 of 21 patients with disseminated bartonellosis were cured with antimicrobial therapy. Two patients, both of whom had endocarditis, died. Among solid organ transplant recipients, infection with B. henselae is uncommon and has diverse disease manifestations including disseminated disease. Persistent fevers or lymphadenopathy in a transplant recipient who has been exposed to cats should prompt clinicians to maintain a high index of suspicion for B. henselae infection. Identifying B. henselae as the causative organism often requires multiple diagnostic studies. Once the diagnosis is established, most solid organ transplant recipients respond appropriately to antimicrobial treatment.

Ocular bacillary angiomatosis in an immunocompromised man

An immunocompromised man presented with an inflammatory eyelid lesion. Biopsy was performed; histopathology and special staining confirmed a diagnosis of bacillary angiomatosis. The man was treated with oral erythromycin, and the lesion resolved. The etiologic agents of bacillary angiomatosis are Bartonella henselae and Bartonella quintana, Gram-negative coccobacilli. The organisms stain positively with the Warthin-Starry silver stain. Lesions can be cutaneous or visceral and have been commonly described in immunocompromised patients. Histopathologic examination of lesions reveals angiogenesis and cellular proliferation. Bacillary angiomatosis can be treated with oral antibiotics.

Selected Pseudoneoplastic Lesions of the Skin

Context.—Pseudoneoplastic cutaneous lesions are diverse, not only morphologically but also with respect to their causes and cellular lineages. They include proliferations of epithelial, as well as mesenchymal, elements.

Objective.—This review aims to consider selected lesions in the aforementioned groups, contrasting them with histologically similar neoplasms of the skin in a differential diagnostic setting.

Data Sources.—Information used in assembling this discussion was drawn from the published literature on cutaneous pseudoneoplasms, using an Internet-based search engine. The authors' collective experience was also used in writing this review.

Conclusions.—Sufficient clinical and morphologic differences exist in virtually all instances to separate pseudoneoplastic cutaneous proliferations from the tumors that they imitate.

Computed tomography and magnetic resonance imaging of cat-scratch disease: a report of two cases

Cat-scratch disease (CSD) is a bacterial infection that typically causes swelling of the lymph nodes. The patients usually have a history of being scratched, bitten, or licked by cats and often by kittens. Understanding the characteristic radiological and clinical features may lead to a noninvasive diagnosis and prevent unnecessary invasive procedures. We report two cases of CSD with computed tomography and magnetic resonance imaging showing nodules or masses of lymphadenopathy with subcutaneous edema and fat infiltration in the lymphatic drainage area. The imaging features and clinical manifestations are described, and the differential diagnosis of CSD is discussed.

Native valve endocarditis due to Bartonella henselae in an immunocompetent man

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

Evaluation of an in-house cat scratch disease IgM ELISA to detect Bartonella henselae in a routine laboratory setting

Cat scratch disease (CSD) is caused by Bartonella henselae infection and is a common cause of regional lymphadenopathy. The diagnosis of CSD largely depends on serology, but detection of B. henselae in an affected lymph node by PCR is also an important diagnostic tool. We evaluated an IgM in-house ELISA protocol and analyzed its performance in routine CSD serology. Serum samples from PCR-positive patients (n = 126), PCR-negative patients (n = 123), and age-matched controls (n = 126) were used for evaluation. The sensitivity of the IgM ELISA was only 56%, showing that the performance of B. henselae serology under routine laboratory settings is low, probably caused by the wide variability in disease duration in patients suspected of CSD whose samples were submitted to our laboratory. Most patients (46%) with a positive IgM response were between 0 and 20 years of age. We conclude that the serodiagnosis of B. henselae is hampered by the low sensitivity and specificity of the assays when used in a routine laboratory setting. For this reason, a negative IgM or PCR result can never exclude CSD, especially with late sample collection.

Schmerzhafte Weichteilschwellung am Oberarm

Cat-scratch disease is an infection by Bartonella henselea and resolves spontaneously. We present a case of untypical Bartonella infection which was misinterpreted by MRI as a soft-tissue sarcoma of the upper arm. The histological findings of an incision biopsy were unspecific, without signs of malignancy. The tumor was excised completely and the final histology, however, showed no evidence of malignant changes. The Bartonella henselae infection could be confirmed by polymerase chain reaction. The untypical presentation of cat-scratch disease should be considered in the differential diagnosis of clinically suspected soft tissue sarcoma.

Recurrent expressive aphasia as a presentation of cat-scratch encephalopathy

Cat-scratch disease is a common disease, occurring in an estimated 24,000 patients annually in the United States, and is one of the most common causes of chronic lymphadenitis in children. A wide array of neurologic complications occurs as a result of cat-scratch disease. However, there have been no reports of acute-onset, self-resolving, recurrent, expressive aphasia, as we report here in an adolescent boy. In our case, establishing the diagnosis of cat-scratch encephalopathy saved time and resources and afforded the family a benign diagnosis. Cat-scratch encephalopathy must be considered in the differential diagnoses when pediatric patients present with unusual neurologic symptoms.

Isolation of Bacteriophages from Bartonella vinsonii subsp. berkhoffii and the Characterization of Pap31 Gene Sequences from Bacterial and Phage DNA

Bacteriophages enhance bacterial survival, facilitate bacterial adaptation to new environmental conditions, assist in the adaptation to a new host species, and enhance bacterial evasion or inactivation of host defense mechanisms. We describe the detection and purification of a novel tailed bacteriophage from Bartonella vinsonii subsp. berkhoffii, which was previously described as a bacteriophage-negative species. We also compare B. vinsonii subsp. berkhoffi Pap31 bacteriophage gene sequences to B. henselae (Houston I), and B. quintana (Fuller) bacteriophage Pap31 sequences. Negative staining electron microscopy of log phase culturesof B. vinsonii subsp. berkhoffii identified bacteriophages, possessing a 50-nm icosahedric head diameter and a 60- to 80-nm contractile tail. Sequence analysis of the bacteriophage Pap31 gene from B. vinsonii subsp. berkhoffii showed three consensus sequences and a 12-bp insertion when compared with Pap31 gene sequences from B. henselae (Houston I) and B. quintana (Fuller) bacteriophages. Isolation of B. vinsonii subsp. berkhoffii bacteriophages containing a Pap31 gene suggests that this heme-binding protein gene might play an important role in bacterial virulence through the genetic exchange of DNA within this subspecies. Defining phage-associated genes may also contribute to the enhanced understanding of the evolutionary relationships among members of the genus Bartonella.

Interaction of Bartonella henselae with endothelial cells promotes monocyte/macrophage chemoattractant protein 1 gene expression and protein production and triggers monocyte migration

Bacillary angiomatosis (BA), one of the many clinical manifestations resulting from infection with the facultative intracellular bacterium Bartonella henselae, is characterized by angiogenic lesions. Macrophages have been identified as important effector cells contributing to the angiogenic process during B. henselae infection by infiltrating BA lesions and secreting vascular endothelial growth factor. Monocyte-macrophage chemoattractant protein 1 (MCP-1) recruits macrophages to sites of inflammation. In this study, we investigated the ability of B. henselae to upregulate MCP-1 gene expression and protein production in the human microvascular endothelial cell line HMEC-1. MCP-1 mRNA was induced at 6 and 24 h after treatment with bacteria, whereas protein production was elevated at 6, 24, and 48 h. This induction was not dependent on the presence of bacterial lipopolysaccharide or endothelial cell toll-like receptor 4. However, MCP-1 production was dependent on NF-kappaB activity. Outer membrane proteins of low molecular weight were able to upregulate MCP-1 production. Furthermore, supernatants from B. henselae-infected HMEC-1 were able to induce chemotaxis of THP-1 monocytes. These data suggest a mechanism by which the macrophage effector cell is recruited to the endothelium during B. henselae infection and then contributes to bacterial-induced angiogenesis.

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.

Unusual trafficking pattern of Bartonella henselae -containing vacuoles in macrophages and endothelial cells

Bartonella henselae, the agent of cat-scratch disease and vasculoproliferative disorders in humans, is a fastidious facultative intracellular pathogen, whose interaction with macrophages and endothelial cells (ECs) is crucial in the pathogenesis of these diseases. However, little is known about the subcellular compartment in which B. henselae resides. Two hours after infection of murine macrophages and human ECs, the majority of B. henselae-containing vacuoles (BCVs) lack typical endocytic marker proteins, fail to acidify, and do not fuse with lysosomes, suggesting that B. henselae resides in a non-endocytic compartment. In contrast to human umbilical vein endothelial cells, bacterial death and lysosomal fusion with BCVs is apparent in J774A.1 macrophages at 24 h. This phenomenon of delayed lysosomal fusion requires bacterial viability, and is confined to the BCV itself. Using magnetic selection, we enriched for transposon-mutagenized B. henselae trapped in lysosomes of macrophages 2 h after infection. Genes affected appear to be relevant to the intracellular lifestyle in macrophages and ECs and include some previously implicated in Bartonella pathogenicity. We conclude that B. henselae has a specific capacity to actively avoid the host endocytic pathway after entry of macrophages and ECs, from within a specialized non-endocytic membrane-bound vacuole.

Prevalence of infectious diseases in feral cats in Northern Florida

Objectives of this study were to determine prevalence of infection in feral cats in Northern Florida with a select group of infectious organisms and to determine risk factors for infection. Blood samples or sera from 553 cats were tested with a panel of antibody, antigen or PCR assays. Male cats were at higher risk for FIV, Mycoplasma haemofelis, and M. haemominutum. Infection with either FeLV or FIV was associated with increased risk for coinfection with the other retrovirus, M. haemofelis, or M. haemominutum. Bartonella henselae had the highest prevalence and was the only organism that did not have any associated risk for coinfection with other organisms. Feral cats in this study had similar or lower prevalence rates of infections than those published for pet cats in the United States. Thus, feral cats assessed in this study appear to be of no greater risk to human beings or other cats than pet cats.

[Solitary nontuberculous mycobacterial infection of a cervical lymph node caused by Bartonella henselae (cat scratch disease)]

Cat scratch disease (CSD) is a common cause of subacute regional lymphadenopathy. Cats are the principal reservoir of Bartonella henselae, the etiologic agent in most cases of CSD. Because the histopathological findings are typical but not specific, a wide range of other agents must be considered in differential diagnosis. We report on a patient with a solitary swelling of the neck which remained over months with initial features suggestive of unspecific lymphadenitis, but who, after careful history taking and further serological testing, had cat scratch disease.

Bartonella henselae inhibits apoptosis in Mono Mac 6 cells

Bartonella henselae causes the vasculoproliferative disorders bacillary angiomatosis and peliosis probably resulting from the release of vasculoendothelial growth factor (VEGF) from infected epithelial or monocytic host cells. Here we demonstrate that B. henselae in addition to VEGF induction was also capable of inhibiting the endogenous sucide programme of monocytic host cells. Our results show that B. henselae inhibits pyrrolidine dithiocarbamate (PDTC)-induced apoptosis in Mono Mac 6 cells. B. henselae was observed to be present in a vacuolic compartment of Mono Mac 6 cells. Direct contact of B. henselae with Mono Mac 6 cells was crucial for inhibition of apoptosis as shown by the use of a two-chamber model. Inhibition of apoptosis was paralleled by diminished caspase-3 activity which was significantly reduced in PDTC-stimulated and B. henselae-infected cells. The anti-apoptotic effect of B. henselae was accompanied by (i) the activation of the transcription factor NF-kappaB and (ii) the induction of cellular inhibitor of apoptosis proteins-1 and -2 (cIAP-1, -2). Our results suggest a new synergistic mechanism in B. henselae pathogenicity by (i) inhibition of host cell apoptosis via activation of NF-kappaB and (ii) induction of host cell VEGF secretion.

Epilepsia partialis continua in cat scratch disease

Cat scratch disease (CSD) is a world-wide, diffuse, non-epidemic infection caused by the Gram-negative bacillus Bartonella henselae. The occurrence of encephalopathy represents an infrequent and atypical complication, whose manifestations include ischemic strokes, transverse myelitis and epileptic seizures. Status epilepticus has been described as the most frequent emergency in CSD encephalopathy. In this report, we describe a case of CSD complicated by an epilepsia partialis continua (EPC) manifested as rhythmic movements of the flexor muscles of the left hand. Although CSD is a benign, self-limited disease and a complete neurological recovery usually occurs, in the present case the EPC resulted in a partial epilepsy. Magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) and back-averaged EEG data recorded during myoclonic activity document this CSD complication.

Clinical implication of prolonged fever in children with cat scratch disease

Cat scratch disease, caused by Bartonella henselae, typically presents with a localized lymphadenopathy with a brief period of fever and general symptoms. However, there are atypical cases with a wide spectrum of clinical manifestations including prolonged fever (> or =37.5 degrees C, for more than 7 days), or with systemic complication, or without lymphadenopathy. We analyzed relationships among those manifestations in children with cat scratch disease. A total of 127 patients were serologically diagnosed as having Bartonella infection between 1997 and 2003. Relationships among clinical manifestations were analyzed by use of multiple regression and multiple logistic regression analyses. Of the 127 seropositive cases, 75 (59.1%) had typical cat scratch disease and 52 (40.9%) had an atypical one. As atypical manifestations, 46 (36.2%) had prolonged fever, 23 (18.1%) had no lymphadenopathy, and 21 (16.5%) had complications: hepatic/splenic abscesses or low-echoic lesions, hepatic granuloma, and central nervous system involvements. Prolonged fever was observed in 20 (87%) of the 23 cases without lymphadenopathy and 16 (76.2%) of the 21 cases with complications. By multiple regression analysis, the duration of fever was significantly associated with both the absence of lymphadenopathy and the presence of complications. The child suffering from cat scratch disease without lymphadenopathy or with complication tends to have prolonged fever. Conversely, when a child has a prolonged fever of unknown origin, possibility of cat scratch disease should be considered, and a search for underlying systemic complications is recommended for prompt diagnosis and appropriate treatment.

Rapid and efficient transposon mutagenesis of Bartonella henselae by transposome technology

Molecular genetics are difficult to perform in Bartonella henselae, the causative agent of cat scratch disease and the vasculoproliferative disorders bacillary angiomatosis and bacillary peliosis. To elucidate the underlying bacterial pathogenic mechanisms, genetic manipulation of B. henselae is the method of choice. We describe how to perform transposon mutagenesis in B. henselae using transposome technology. B. henselae mutants revealed by this technique showed random transpositional insertion into the chromosome. In contrast to transposon mutagenesis by conjugational transfer, transposome technology allows transposon mutagenesis of early passaged Bartonella spp. with approximately 100-fold higher efficiency. The results show that transposome technique is a rapid, efficient and simple method to generate transposon mutants of B. henselae.

The role of the host immune response in pathogenesis of Bartonella henselae

Bartonella henselae can infect humans resulting in a wide range of disease syndromes including cat-scratch disease, fever with bacteremia, endocarditis, bacillary angiomatosis, and bacillary peliosis hepatis, among others. The nature and severity of the clinical presentation correlates well with the status of the hosts' immune system. Individuals with impaired immune function, including HIV infection, progress to systemic infections more often. Patients with intact immune function who become infected with B. henselae usually get cat-scratch disease, a disease that usually involves lymphadenopathy resulting from a strong cellular immune response to the bacterium. However, immunocompromised patients often progress to bacillary angiomatosis or bacillary peliosis hepatis. The reduced ability of the hosts immune response to control bacterial infection apparently results in a bacteremia of longer duration, and in some patients the presence of angiogenic lesions that are unique among bacterial infections to Bartonella. Recently, the role of immune effector cells that produce angiogenic cytokines upon stimulation with B. henselae has been proposed. Here, the current status of the role of the immune response in both controlling infection and in B. henselae-triggered immunopathogenesis is presented.

A heat-stable component of Bartonella henselae upregulates intercellular adhesion molecule-1 expression on vascular endothelial cells

Bartonella henselae upregulated the expression of intercellular adhesion molecule-1 (ICAM-1) on human umbilical vein endothelial cells (HUVECs). The induction level of ICAM-1 depended on the inoculation bacterial dose. ICAM-1 expression began increasing 4 h after infection and reached a sustained peak beginning at 12 h after B. henselae infection; this time course was similar to that of lipopolysaccharide (LPS) of Escherichia coli. The stimulatory effect was abolished when live B. henselae were separated from HUVECs by a filter membrane. The nonpiliated strain, which is unable to invade endothelial cells, induced ICAM-1 expression to the same extent as the piliated strain. Inactivation of B. henselae by ultraviolet (UV) irradiation, heat (56 degrees C, 30 min), or sonication did not alter its stimulatory activity. Polymyxin B, which strongly inhibited the effect of LPS, did not exert any influence on the stimulatory activity of B. henselae. Furthermore, the effect of sonicated B. henselae was not inhibited even by boiling, which was also the case with LPS. Our data suggest that some heat-stable component of B. henselae binds to the endothelial cell surface, inducing ICAM-1 expression. Though the participation of LPS could not be completely ruled out, we suppose that some unidentified heat-stable proteins, lipids, or polysaccharides may be the stimulatory factor(s). The ability of B. henselae to enhance the expression of adhesion molecules on endothelial cells may be an important mechanism in the pathogenesis of B. henselae infection.

Cat-scratch disease: considerations for dentistry

BACKGROUND

Cat-scratch disease, or CSD, results from inoculation of the gram-negative bacillus Bartonella henselae via a cat's scratch. A regional lymphadenitis, which usually is cervical, develops and may progress to suppuration. It is necessary to differentiate CSD from other lymphadenopathies.

CASE DESCRIPTION

A patient who had close contact with a cat subsequently developed a localized, suppurative cervical lymphadenitis. As B. henselae was identified in 1992, the authors were able to confirm the existence of CSD serologically. Surgical drainage resulted in a successful resolution of the disease process.

CLINICAL IMPLICATIONS

As patients with CSD may be seen in the dental office, an awareness of its symptomatology can prevent unnecessary dental intervention and facilitate early treatment.

[Cat scratch disease. Clinical study of 26 patients. Role and importance of PCR]

PURPOSE

Cat scratch disease is a mild pathology but diagnosis often remain difficult.

METHODS

A retrospective study has been conducted by the department of infectious diseases at the University hospital in Angers. Between January 1994 and October 1998, 26 observations were recorded providing the presence of three criteria out of four among the following: contact with a cat, clinical presentation and its favorable course, absence of any other cause noticed, and the presence of either a positive serology or a positive PCR, or the examination of a suggestive pathology.

RESULTS

Fourteen men and 12 women were concerned. From a clinical point of view, the inoculation lesion was observed six times, all patients showed at least one adenopathy during their illness, 12 patients showed only an adenopathy without clinical signs. A surgical biopsy was carried out on nine patients and a diagnosis established. Bartonella henselae serology was done in all patients. Six presented a significant rate of IgG antibodies as early as the first dosage. A seroconversion was observed in four cases belatedly 1 to 2 months after the beginning of the symptomatology. The method's sensitivity was approximately 38%. A PCR search was accomplished in the pus obtained from a ganglionic puncture on 12 patients. It was positive seven times, which corresponds to a sensitivity of about 58%. In associating these two diagnostic criteria a sensitivity rate of nearly 92% was reached, the diagnosis not having been confirmed only in one case. The outcome proved to be favorable in all cases, with or without an antibiotic treatment.

CONCLUSION

The association of serology and PCR in the pus permits a certain diagnosis in the majority of the cases and avoids the more aggressive biopsy.

On the wide spectrum of abnormalities in the coronary arteries of Whipple's disease

BACKGROUND

There is growing interest in the role of microbes in the pathogenesis of coronary atherosclerosis but most of the evidence has been seroepidemiologic. It would be useful to know more about the cytology and histology of coronary lesions containing clearly depicted microbes.

OBJECTIVE

To define carefully the assorted abnormalities apparent in the coronary arteries of individuals dying with Whipple's disease.

METHODS

Myocardial tissue from 12 cases of Whipple's disease was studied by light microscopy. Slides were stained routinely (in sequence) with either the periodic-acid-Schiff (PAS) or Goldner-trichrome method and some with Gomori methenimine silver. Cardiac slides with PAS-positive bacilli were compared to lesions in jejunal lamina propria.

RESULTS

There were abundant sites of coronary arterial damage associated with presence of Whipple bacilli, more in the tunica media than in intima and adventitia. Bacilli in the arterial lesions were identical to those in lamina propria. Medial lesions were often associated with a fibroproliferative 'atheroma'. Both intracellular and extracellular bacilli were found. Most lesions were devoid of inflammation, but some sites exhibited either florid arteritis or dense scarring. Arteries that were scarred or inflamed exhibited only a few bacilli. There was an apparent affinity of bacilli for the nuclei in medial smooth muscle cells and in nearby ventricular myocytes. Apoptosis (TUNEL-positive) was present in medial smooth muscle cells, endothelial cells, and ventricular myocytes.

CONCLUSIONS

There is a wide spectrum of coronary abnormalities in Whipple's disease. It would be useful to know how often the Whipple bacillus is a part of the total pathogen burden in coronary disease.

Intestinal inflammatory pseudotumour with regional lymph node involvement: identification of a new bacterium as the aetiological agent

Inflammatory pseudotumours are the morphological expression of diverse processes such as reactive/reparative, infective, and neoplastic. This paper reports an example of intestinal inflammatory pseudotumour, with identification of a newly characterized bacterium in the lesion. The patient presented with intestinal obstruction. Laparotomy revealed a tumour in the terminal ileum causing stricture, and multiple enlarged regional lymph nodes. Histologically, the tumour and lymph nodes were composed of plump spindle cells disposed in a vague storiform pattern, and associated with lymphocytes and plasma cells. Immunohistochemical studies showed that most of the spindle cells were histiocytes (CD68 positive), prompting a search for a bacterial aetiology, akin to mycobacterial spindle cell pseudotumour. All histochemical stains for micro-organisms were unrewarding. Ultrastructural studies, however, revealed abundant bacteria within the spindle histiocytes. Polymerase chain reaction, using conserved oligonucleotide primers complementary to the 16S rRNA genes of eubacteria, was employed to amplify 16S rRNA gene fragments directly from the involved lymph node tissue. Phylogenetic analysis of the amplified DNA sequences revealed an organism with 99% sequence conformity to Pseudomonas veronii, a bacterium which has hitherto not been implicated in human infection. The importance of searching for an infective agent in inflammatory pseudotumour in the appropriate setting is re-emphasized.