Molecular epidemiology of bartonella infections in patients with bacillary angiomatosis-peliosis

Bacillary Angiomatosis in a Patient With HIV and Disseminated Mycobacterium avium Complex Infection

Bartonella is a genus of arthropod-borne bacterial pathogens that typically cause persistent infections of erythrocytes and endothelial cells in mammalian hosts. The species that primarily infect humans are Bartonella henselae and Bartonella quintana. Depending on immune status, the clinical presentation of B. henselae may differ, manifesting as cat-scratch disease in immunocompetent individuals or bacillary angiomatosis (BA) and peliosis in immunocompromised patients. The cutaneous manifestations of BA are typically characterized by occasionally painful, angiomatous papules and nodules, often with a chronic, persistent course. Herein, we present a case of biopsy-confirmed B. henselae infection in a 32-year-old HIV-positive female with acquired immunodeficiency syndrome in the setting of disseminated Mycobacterium avium complex infection, an association that has been less frequently described. This case serves as an important reminder to consider uncommon opportunistic infectious etiologies when examining immunocompromised patients, as prompt diagnosis and treatment are essential in this patient population.

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.

Antibodies to Borrelia burgdorferi and Bartonella species in serum and synovial fluid from people with rheumatic diseases

Vector-borne infections may underlie some rheumatic diseases, particularly in people with joint effusions. This study aimed to compare serum and synovial fluid antibodies to B. burgdorferi and Bartonella spp. in patients with rheumatic diseases. This observational, cross-sectional study examined paired synovial fluid and serum specimens collected from 110 patients with joint effusion between October 2017 and January 2022. Testing for antibodies to B. burgdorferi (using CDC criteria) and Bartonella spp. via two indirect fluorescent antibody (IFA) assays was performed as part of routine patient care at the Institute for Specialized Medicine (San Diego, CA, USA). There were 30 participants (27%) with positive two-tier B. burgdorferi serology and 26 participants (24%) with IFA seroreactivity (≥1:256) to B. henselae and/or B. quintana. Both B. burgdorferi IgM and IgG were detected more frequently in synovial fluid than serum: 27% of patients were either IgM or IgG positive in synovial fluid, compared to 15.5% in serum (P = 0.048). Conversely, B. henselae and B. quintana antibodies were detected more frequently in serum than synovial fluid; overall only 2% of patients had positive IFA titers in synovial fluid, compared to 24% who had positive IFA titers in serum (P < 0.001). There were no significant associations between B. burgdorferi or Bartonella spp. seroreactivity with any of the clinical rheumatological diagnoses. This study provides preliminary support for the importance of synovial fluid antibody testing for documenting exposure to B. burgdorferi but not for documenting exposure to Bartonella spp.

IMPORTANCE

This study focuses on diagnostic testing for two common vector-borne diseases in an affected patient population. In it, we provide data showing that antibodies to B. burgdorferi, but not Bartonella spp., are more commonly found in synovial fluid than serum of patients with joint effusion. Since Lyme arthritis is a common-and sometimes difficult to diagnose-rheumatic disease, improving diagnostic capabilities is of utmost importance. While our findings are certainly not definitive for changes to practice, they do suggest that synovial fluid could be a useful sample for the clinical diagnosis of Lyme disease, and future prospective studies evaluating this claim are warranted.

An autochthonous case of cutaneous bacillary angiomatosis not related to major immunosuppression: An emerging or overlooked disease?

Cutaneous bacillary angiomatosis (cBA) is a vascular proliferative disorder due to Bartonella henselae or Bartonella quintana that has been mostly described in people living with HIV. Since cBA is considered to be rare in hosts not affected by major immunosuppression, it could be underdiagnosed in this population. Moreover, antimicrobial treatment of cBA has been poorly validated, thus reporting experiences on this clinical entity is important. We reported a challenging and well-characterized case of an Italian 67-year-old gentleman without a history of major immunocompromizing conditions, although he was affected by conditions that can be associated with impaired immune function. The patient reported herein was diagnosed after a long time since the initiation of symptoms and was successfully treated with combined antibiotic therapy including macrolides and quinolones under the guidance of molecular test results. Physicians should consider cBA as a possible manifestation of Bartonella spp. Infection in patients not suffering from major immunocompromizing 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.

Viability and Desiccation Resistance of Bartonella henselae in Biological and Non-Biological Fluids: Evidence for Pathogen Environmental Stability

Pathogen environmental stability is an often-neglected research priority for pathogens that are known to be vector-transmitted. Bartonella henselae, the etiologic agent of Cat Scratch Disease, has become a "pathogen of interest" in several serious human illnesses, which include neoplastic, cardiovascular, neurocognitive, and rheumatologic conditions. Survival in the flea gut and feces as well as the association with a biofilm in culture-negative endocarditis provides insight into this organism's ability to adjust to environmental extremes. The detection of B. henselae DNA in blood and tissues from marine mammals also raises questions about environmental stability and modes of pathogen transmission. We investigated the ability of B. henselae to survive in fluid matrices chosen to mimic potential environmental sources of infective materials. Feline whole blood, serum and urine, bovine milk, and physiologic saline inoculated with a laboratory strain of B. henselae San Antonio 2 were subsequently evaluated by culture and qPCR at specified time intervals. Bacterial viability was also assessed following desiccation and reconstitution of each inoculated fluid matrix. Bartonella henselae SA2 was cultured from feline urine up to 24 h after inoculation, and from blood, serum, cow's milk, and physiologic saline for up to 7 days after inoculation. Of potential medical importance, bacteria were cultured following air-desiccation of all fluid inoculates. The viability and stability of Bartonella within biological and non-biological fluids in the environment may represent a previously unrecognized source of infection for animals and human beings.

Haemophagocytic lymphohistiocytosis associated with bartonella peliosis hepatis following kidney transplantation in a patient with HIV

Bacillary peliosis hepatis is a well recognised manifestation of disseminated Bartonella henselae infection that can occur in immunocompromised individuals. Haemophagocytic lymphohistiocytosis is an immune-mediated condition with features that can overlap with a severe primary infection such as disseminated Bartonella spp infection. We report a case of bacillary peliosis hepatis and secondary haemophagocytic lymphohistiocytosis due to disseminated Bartonella spp infection in a kidney-transplant recipient with well controlled HIV. The patient reported 2 weeks of fever and abdominal pain and was found to have hepatomegaly. He recalled exposure to a sick dog but reported no cat exposures. Laboratory evaluation was notable for pancytopenia and cholestatic injury. The patient met more than five of eight clinical criteria for haemophagocytic lymphohistiocytosis. Pathology review of a bone marrow core biopsy identified haemophagocytosis. A transjugular liver biopsy was done, and histopathology review identified peliosis hepatis. Warthin-Starry staining of the bone marrow showed pleiomorphic coccobacillary organisms. The B henselae IgG titre was 1:512, and Bartonella-specific DNA targets were detected by peripheral blood PCR. Treatment with doxycycline, increased prednisone, and pausing the mycophenolate component of his transplant immunosuppression regimen resulted in an excellent clinical response. Secondary haemophagocytic lymphohistiocytosis can be difficult to distinguish from severe systemic infection. A high index of suspicion can support the diagnosis of systemic Bartonella spp infection in those who present with haemophagocytic lymphohistiocytosis, especially in patients with hepatomegaly, immunosuppression, and germane animal exposures.

A Review of Bartonella Infections in California-Implications for Public and Veterinary Health

Bartonella are vector-transmitted, intracellular bacteria that infect a wide variety of blood-feeding arthropods and their vertebrate hosts. In California, more than 13 species of Bartonella have been described from companion animals, livestock, and wildlife, of which four have been associated with human disease. Infections in humans cause a range of symptoms from relatively mild to severe, especially in immunocompromised individuals. Exposure to infected domestic animals and wildlife, and their ectoparasites, may increase the risk of cross-species transmission. The objective of this review was to compile and summarize published materials on human and animal Bartonella infections in California. Medical and veterinary case reports of bartonellosis were highlighted in an effort to increase the awareness of this poorly understood and potentially under-recognized disease among healthcare professionals and veterinarians.

Hundreds of vasculoproliferative skin lesions in a paediatric renal transplant recipient

Bacillary angiomatosis is a vasculoproliferative infectious disease mostly recorded in patients with human immunodeficiency virus and rarely in organ transplant recipients. We report the first case of bacillary angiomatosis due to Bartonella quintana in a paediatric renal transplant patient with skin, lymph node and bone involvement with excellent response to doxycycline.

Serologic study of Bartonella sp. infection among human population of Southern Spain

INTRODUCTION

The purpose of this study was to determine the prevalence of IgG antibodies against Bartonella sp. in a randomly selected sample from the population of the patients of North Sanitary District of Jaén.

METHODS

We used a commercially available immunofluorescent test (Focus-Technology IFA Bartonella quintana and B. henselae test).

RESULTS

Six hundred five healthy individuals were divided by sex into three age groups. We detected that 13.55% and 11.07% subjects were IgG seropositive to B. henselae and B. quintana, respectively.

CONCLUSIONS

Our data show that the prevalence of both Bartonella species in Andalusia (Southern Spain) is relatively high. No statistical difference in the seropositivity was observed among these groups. In both cases, the IgG antibody titers ranged from 1/128 to 1/512.

Development of a Multiplex Droplet Digital PCR Assay for the Detection of Babesia, Bartonella, and Borrelia Species

We describe the development, optimization, and validation of a multiplex droplet digital PCR (ddPCR) assay for the simultaneous detection of Babesia, Bartonella, and Borrelia spp. DNA from several sample matrices, including clinical blood samples from animals and humans, vectors, in-vitro infected human and animal cell lines, and tissues obtained from animal models (infected with Bartonella and/or B. burgdorferi). The multiplex ddPCR assay was able to detect 31 Bartonella, 13 Borrelia, and 24 Babesia species, including Theileria equi, T. cervi, and Cytauxzoon felis. No amplification of Treponema or Leptospira spp. was observed. Sensitivity of 0.2-5 genome equivalent DNA copies per microliter was achieved for different members of the Bartonella and Borrelia genus, depending on the species or matrix type (water or spiked blood DNA) tested. The ddPCR assay facilitated the simultaneous detection of co-infections with two and three vector-borne pathogens comprising four different genera (Babesia, Bartonella, Borrelia, and Theileria) from clinical and other sample sources.

Is Mycobacterium tuberculosis carcinogenic to humans?

We highlight the ability of the tuberculosis (TB) causing bacterial pathogen, Mycobacterium tuberculosis (Mtb), to induce key characteristics that are associated with established IARC classified Group 1 and Group 2A carcinogenic agents. There is sufficient evidence from epidemiological case-control, cohort and meta-analysis studies of increased lung cancer (LC) risk in pre-existing/active/old TB cases. Similar to carcinogens and other pathogenic infectious agents, exposure to aerosol-containing Mtb sprays in mice produce malignant transformation of cells that result in squamous cell carcinoma. Convincing, mechanistic data show several characteristics shared between TB and LC which include chronic inflammation, genomic instability and replicative immortality, just to name a few cancer hallmarks. These hallmarks of cancer may serve as precursors to malignant transformation. Together, these findings form the basis of our postulate that Mtb is a complete human pulmonary carcinogen. We also discuss how Mtb may act as both an initiating agent and promoter of tumor growth. Forthcoming experimental studies will not only serve as proof-of-concept but will also pivot our understanding of how to manage/treat TB cases as well as offer solutions to clinical conundrums of TB lesions masquerading as tumors. Clinical validation of our concept may also help pave the way for next generation personalized medicine for the management of pulmonary TB/cancer particularly for cases that are not responding well to conventional chemotherapy or TB drugs.

Clear Cell Change in Reactive Angiogenesis: A Potential Diagnostic Pitfall

Reactive angiogenesis is commonplace, occurs in many circumstances, and is important in the repair of injured tissue. Histologically, it is characterized by newly formed capillaries arranged in a lobular architecture and lined by plump endothelial cells. We have encountered a form of reactive angiogenesis not well described; composed of large endothelial cells with abundant clear cytoplasm that causes diagnostic challenges. The cohort includes 10 patients, aged 4 to 61, mean 40 years; 7 males, 3 females. One case involved bone (ilium), and 9 involved soft tissue: fingers (n=2), toes (n=2), hip joint (n=1), shoulder (n=1), thigh (n=2), and anal mucosa (n=1). Clinically, the patients had chronic ulcers, osteomyelitis, or localized infection. All cases exhibited a lobular proliferation of capillaries lined by large polyhedral endothelial cells that obscured the vessel lumens and were admixed with acute and chronic inflammation. The endothelial nuclei were vesicular with small nucleoli and the cytoplasm was abundant and clear or palely eosinophilic. The endothelial cells were stained with CD31 and ERG (7/7 cases), CD34 (6/6), FLI1 (4/4), and were negative for keratin and CD68 (6/6). Periodic acid-Schiff stain and periodic acid-Schiff stain-diastase on 3 cases did not demonstrate glycogen. Using a polymerase chain reaction, no Bartonella henselae was found in all 6 cases tested. Reactive angiogenesis with clear cell change unassociated with Bartonella spp. has not been described. It causes diagnostic challenges and the differential diagnosis includes benign and malignant tumors, as well as unusual infections. It is important to distinguish between these possibilities because of the significant impact on treatment and prognosis.

Human dental pulp stem cells: A sanctuary for relapsing Bartonella quintana

Bartonella quintana is a facultative intracellular bacterium responsible for relapsing fever, an example of non-sterilizing immunity. The cellular sanctuary of B. quintana in-between febrile relapses remains unknown but repeated detection of B. quintana in dental pulp specimens suggested long-term half-life dental pulp stem cells (DPSCs) as candidates. As the capacity of DPSCs to internalize microscopic particles was unknown, we confirmed that DPSCs internalized B. quintana bacteria: Gimenez staining and fluorescence microscopy localized B. quintana bacteria inside DPSCs and this internalization did not affect the cellular multiplication of DPSCs during a one-month follow-up despite the increase in the bacterial load. B. quintana-infected DPSCs did not produce Tumor Necrosis Factor-α whereas an important production of Monocytes Chemoattractant Protein-1 was observed. These unprecedented observations suggest the possibility that DPSCs are shelters for the long-term persistence of B. quintana in the host, warranting further experimental and clinical investigations.

Serologic study of Bartonella sp. infection among human population of Southern Spain

INTRODUCTION

The purpose of this study was to determine the prevalence of IgG antibodies against Bartonella sp. in a randomly selected sample from the population of the patients of North Sanitary District of Jaén.

METHODS

We used a commercially available immunofluorescent test (Focus-Technology IFA Bartonella quintana and B. henselae test).

RESULTS

Six hundred five healthy individuals were divided by sex into three age groups. We detected that 13.55% and 11.07% subjects were IgG seropositive to B. henselae and B. quintana, respectively.

CONCLUSIONS

Our data show that the prevalence of both Bartonella species in Andalusia (Southern Spain) is relatively high. No statistical difference in the seropositivity was observed among these groups. In both cases, the IgG antibody titers ranged from 1/128 to 1/512.

Case Report: Bartonella quintana Endocarditis Outside of the Europe-African Gradient: Comprehensive Review of Cases within North America

Clinical syndromes associated with Bartonella quintana infection can be insidious and difficult to diagnose for multiple reasons. Clinically, B. quintana can manifest as asymptomatic bacteremia or with subtle subacute constitutional symptoms. Second, it is a fastidious organism that is difficult to identify using traditional culture methods. Last, the body lice vector of B. quintana transmission is likely not uncommon in most patients affected, who are homeless and of low socioeconomic status. Therefore, barriers in seeking medical care and financial constraints for medications are important considerations. The mainstay of literature surrounding B. quintana endocarditis is from Europe and the developing nations. Herein, we describe a case of native valve endocarditis secondary to B. quintana in a homeless male with preexisting valvular disease and undertake a comprehensive literature review of documented B. quintana endocarditis in North America.

Bartonella infections in cats and dogs including zoonotic aspects

Bartonellosis is a vector-borne zoonotic disease with worldwide distribution that can infect humans and a large number of mammals including small companion animals (cats and dogs). In recent years, an increasing number of studies from around the world have reported Bartonella infections, although publications have predominantly focused on the North American perspective. Currently, clinico-pathological data from Europe are more limited, suggesting that bartonellosis may be an infrequent or underdiagnosed infectious disease in cats and dogs. Research is needed to confirm or exclude Bartonella infection as a cause of a spectrum of feline and canine diseases. Bartonella spp. can cause acute or chronic infections in cats, dogs and humans. On a comparative medical basis, different clinical manifestations, such as periods of intermittent fever, granulomatous inflammation involving the heart, liver, lymph nodes and other tissues, endocarditis, bacillary angiomatosis, peliosis hepatis, uveitis and vasoproliferative tumors have been reported in cats, dogs and humans. The purpose of this review is to provide an update and European perspective on Bartonella infections in cats and dogs, including clinical, diagnostic, epidemiological, pathological, treatment and zoonotic aspects.

Comparative proteomic analysis of outer membrane protein 43 (omp43)-deficient Bartonella henselae

Outer membrane proteins (OMPs) of Gram-negative bacteria constitute the first line of defense protecting cells against environmental stresses including chemical, biophysical, and biological attacks. Although the 43-kDa OMP (OMP43) is major porin protein among Bartonella henselae-derived OMPs, its function remains unreported. In this study, OMP43-deficient mutant B. henselae (Δomp43) was generated to investigate OMP43 function. Interestingly, Δomp43 exhibited weaker proliferative ability than that of wild-type (WT) B. henselae. To study the differences in proteomic expression between WT and Δomp43, two-dimensional gel electrophoresis-based proteomic analysis was performed. Based on Clusters of Orthologus Groups functional assignments, 12 proteins were associated with metabolism, 7 proteins associated with information storage and processing, and 3 proteins associated with cellular processing and signaling. By semi-quantitative reverse transcriptase polymerase chain reaction, increases in tldD, efp, ntrX, pdhA, purB, and ATPA mRNA expression and decreases in Rho and yfeA mRNA expression were confirmed in Δomp43. In conclusion, this is the first report showing that a loss of OMP43 expression in B. henselae leads to retarded proliferation. Furthermore, our proteomic data provide useful information for the further investigation of mechanisms related to the growth of B. henselae.

Body lice of homeless people reveal the presence of several emerging bacterial pathogens in northern Algeria

BACKGROUND

Human lice, Pediculus humanus, are obligate blood-sucking parasites. Body lice, Pediculus h. humanus, occur in two divergent mitochondrial clades (A and D) each exhibiting a particular geographic distribution. Currently, the body louse is recognized as the only vector for louse-borne diseases. In this study, we aimed to study the genetic diversity of body lice collected from homeless populations in three localities of northern Algeria, and to investigate louse-borne pathogens in these lice.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, 524 body lice specimens were collected from 44 homeless people in three localities: Algiers, Tizi Ouzou and Boumerdès located in northern Algeria. Duplex clade specific real-time PCRs (qPCR) and Cytochrome b (cytb) mitochondrial DNA (mtDNA) analysis were performed in order to identify the mitochondrial clade. Screening of louse-borne pathogens bacteria was based on targeting specific genes for each pathogen using qPCR supplemented by sequencing. All body lice belong to clade A. Through amplification and sequencing of the cytb gene we confirmed the presence of three haplotypes: A5, A9 and A63, which is novel. The molecular investigation of the 524 body lice samples revealed the presence of four human pathogens: Bartonella quintana (13.35%), Coxiella burnetii (10.52%), Anaplasma phagocytophilum (0.76%) and Acinetobacter species (A. baumannii, A. johnsonii, A. berezeniae, A. nosocomialis and A. variabilis, in total 46.94%).

CONCLUSIONS/SIGNIFICANCE

To the best of our knowledge, our study is the first to show the genetic diversity and presence of several emerging pathogenic bacteria in homeless' body lice from Algeria. We also report for the first time, the presence of several species of Acinetobacter in human body lice. Our results highlight the fact that body lice may be suspected as being a much broader vector of several pathogenic agents than previously thought. Nevertheless, other studies are needed to encourage epidemiological investigations and surveys of louse-associated infections.

Detection of Bartonella in cat scratch disease using a single-step PCR assay kit

PURPOSE

Bartonella is an increasingly isolated emerging pathogen that can cause severe illness in humans, including cat scratch disease (CSD). The bacteria are difficult to grow and thus many detection methods have been developed, especially molecular. We previously developed a PCR method targeting ribC to identify Bartonella sp. A manufactured kit (RealCycler BART, Progenie Molecular) was commercialised shortly thereafter for the detection of Bartonella infection, including Bartonella henselae.

METHODOLOGY

We performed a comparison between this test and our in-house PCR assay on 73 lymphadenopathy samples sent to the laboratory for suspicion of CSD.Results/Key findings. Among the 28 positive samples for Bartonella, 21 were identified by the two PCR assays, and seven by the commercial kit only.

CONCLUSION

The performance of this commercial kit suggests that it could be a suitable alternative to our in-house PCR assay, highlighting the importance of the molecular methods used to diagnose CSD.

Detection of bacterial pathogens including potential new species in human head lice from Mali

In poor African countries, where no medical and biological facilities are available, the identification of potential emerging pathogens of concern at an early stage is challenging. Head lice, Pediculus humanus capitis, have a short life, feed only on human blood and do not transmit pathogens to their progeny. They are, therefore, a perfect tool for the xenodiagnosis of current or recent human infection. This study assessed the occurrence of bacterial pathogens from head lice collected in two rural villages from Mali, where a high frequency of head lice infestation had previously been reported, using molecular methods. Results show that all 600 head lice, collected from 117 individuals, belonged to clade E, specific to West Africa. Bartonella quintana, the causative agent of trench fever, was identified in three of the 600 (0.5%) head lice studied. Our study also shows, for the first time, the presence of the DNA of two pathogenic bacteria, namely Coxiella burnetii (5.1%) and Rickettsia aeschlimannii (0.6%), detected in human head lice, as well as the DNA of potential new species from the Anaplasma and Ehrlichia genera of unknown pathogenicity. The finding of several Malian head lice infected with B. quintana, C. burnetii, R. aeschlimannii, Anaplasma and Ehrlichia is alarming and highlights the need for active survey programs to define the public health consequences of the detection of these emerging bacterial pathogens in human head lice.

Emerging Infections and Pertinent Infections Related to Travel for Patients with Primary Immunodeficiencies

In today's global economy and affordable vacation travel, it is increasingly important that visitors to another country and their physician be familiar with emerging infections, infections unique to a specific geographic region, and risks related to the process of travel. This is never more important than for patients with primary immunodeficiency disorders (PIDD). A recent review addressing common causes of fever in travelers provides important information for the general population Thwaites and Day (N Engl J Med 376:548-560, 2017). This review covers critical infectious and management concerns specifically related to travel for patients with PIDD. This review will discuss the context of the changing landscape of infections, highlight specific infections of concern, and profile distinct infection phenotypes in patients who are immune compromised. The organization of this review will address the environment driving emerging infections and several concerns unique to patients with PIDD. The first section addresses general considerations, the second section profiles specific infections organized according to mechanism of transmission, and the third section focuses on unique phenotypes and unique susceptibilities in patients with PIDDs. This review does not address most parasitic diseases. Reference tables provide easily accessible information on a broader range of infections than is described in the text.

Dynamics of Co-Infection with Bartonella henselae Genotypes I and II in Naturally Infected Cats: Implications for Feline Vaccine Development

Bartonella henselae is an emerging bacterial pathogen causing cat-scratch disease and potentially fatal bacillary angiomatosis in humans. Bacteremic cats constitute a large reservoir for human infection. Although feline vaccination is a potential strategy to prevent human infection, selection of appropriate B. henselae strains is critical for successful vaccine development. Two distinct genotypes of B. henselae (type I, type II) have been identified and are known to co-infect the feline host, but very little is known about the interaction of these two genotypes during co-infection in vivo. To study the in vivo dynamics of type I and type II co-infection, we evaluated three kittens that were naturally flea-infected with both B. henselae type I and type II. Fifty individual bloodstream isolates from each of the cats over multiple time points were molecularly typed (by 16S rRNA gene sequencing), to determine the prevalence of the two genotypes over 2 years of persistent infection. We found that both B. henselae genotypes were transmitted simultaneously to each cat via natural flea infestation, resulting in mixed infection with both genotypes. Although the initial infection was predominately type I, after the first 2 months, the isolated genotype shifted to exclusively type II, which then persisted with a relapsing pattern. Understanding the parameters of protection against both genotypes of B. henselae, and the competitive dynamics in vivo between the two genotypes, will be critical in the development of a successful feline vaccine that can ultimately prevent B. henselae transmission to human contacts.

The First Report of Bartonella quintana Immune Reconstitution Inflammatory Syndrome Complicated by Jarisch-Herxheimer Reaction

Bacillary angiomatosis (BA) is a rare complication of human immune deficiency virus (HIV) infection in the post-antiretroviral therapy (ART) era, and few cases of BA-associated immune reconstitution inflammatory syndrome (IRIS) have been described. We report the case of a 50-year-old man who presented with mass lesions involving the skin, subcutaneous tissues, muscle, and bone. The diagnosis of Bartonella quintana BA was confirmed by serum polymerase chain reaction. The patient's treatment course was complicated by both IRIS and Jarisch-Herxheimer reaction. The case had a favorable outcome with supportive care and continuation of ART and doxycycline.

Diverse Clinical Signs of Ocular Involvement in Cat Scratch Disease

Objectives:

To describe ocular manifestations, diagnosis, and treatment of cat scratch disease.

Materials and Methods:

Clinical records of patients with ocular cat scratch disease were reviewed.

Results:

Thirteen eyes of 10 patients (7 female, 3 male) with a mean age of 26.9±18.5 years were included. Nine patients had a history of cat contact and had systemic symptoms associated with cat scratch disease 2-90 days prior to the ocular symptoms. Ocular signs were: neuroretinitis in 4 eyes (associated with serous retinal detachment in the inferior quadrant in 1 eye), optic neuropathy in 2 eyes (1 papillitis and optic disc infiltration, 1 optic neuritis), retinal infiltrates in 6 eyes, retinochoroiditis in 1 eye, branch retinal arteriolar occlusion in 3 eyes, and endophthalmitis in 1 eye. Visual acuities at presentation were 1.0 in 7 eyes, 0.3 in 1 eye, ≤0.1 in 4 eyes, and light perception in 1 eye. Bartonella henselae immunoglobulin (Ig) M and/or IgG were positive in all patients. Systemic antibiotic therapy was administered in all patients. Systemic corticosteroid treatment (15-40 mg/day) was added to the therapy in 4 patients, following 5 days of intravenous pulse methylprednisolone in 2 patients. Treatment was ongoing for 1 patient and the mean treatment duration of the other 9 patients was 47±14.5 days. Visual acuities at final visit were 1.0 in 9 eyes, 0.8 in 1 eye, 0.4 in 1 eye, and no light perception in 1 eye.

Conclusion:

Cat scratch disease may present with different ocular signs and should be considered in the differential diagnosis in patients with such presentations.

Pathology of Bartonella Endocarditis in Six Dogs

In a 5-year retrospective study of dogs presenting to the Veterinary Medical Teaching Hospital at the University of California, Davis, there were 31 histologic diagnoses of valvular endocarditis. By polymerase chain reaction (PCR) amplification of embedded valvular tissue, Bartonella organisms were exclusively associated with 6 out of 31 cases (19%). Confirmed Bartonella cases involved the aortic valve alone (five out of six) or in combination with the mitral valve (one of six). Microscopic features of Bartonella endocarditis were compared with valves from non -Bartonella endocarditis and with valvular change unrelated to infectious agents (endocardiosis). Features of Bartonella endocarditis included a combination of fibrosis, mineralization, endothelial proliferation, and neovascularization with variable inflammation. None of these features is specific; however, the combination is distinct both from endocarditis caused by culturable bacteria and from endocardiosis. Ultrastructural analyses revealed both extracellular and intraendothelial bacteria. Clinical history, serology, and PCR are currently necessary to establish an etiologic diagnosis of Bartonella endocarditis.

Zoonotic and Vector-Borne Infections Among Urban Homeless and Marginalized People in the United States and Europe, 1990-2014

INTRODUCTION

In high-income countries, homeless individuals in urban areas often live in crowded conditions with limited sanitation and personal hygiene. The environment of homelessness in high-income countries may result in intensified exposure to ectoparasites and urban wildlife, which can transmit infections. To date, there have been no systematic evaluations of the published literature to assess vector-borne and zoonotic disease risk to these populations.

OBJECTIVES

The primary objectives of this study were to identify diversity, prevalence, and risk factors for vector-borne and zoonotic infections among people experiencing homelessness and extreme poverty in urban areas of high-income countries.

METHODS

We conducted a systematic review and narrative synthesis of published epidemiologic studies of zoonotic and vector-borne infections among urban homeless and very poor people in the United States and Europe from 1990 to 2014.

RESULTS

Thirty-one observational studies and 14 case studies were identified (n = 45). Seroprevalence to the human louse-borne pathogen Bartonella quintana (seroprevalence range: 0-37.5%) was identified most frequently, with clinical disease specifically observed among HIV-positive individuals. Seropositivity to Bartonella henselae (range: 0-10.3%) and Rickettsia akari (range: 0-16.2%) was noted in multiple studies. Serological evidence of exposure to Rickettsia typhi, Rickettsia prowazekii, Bartonella elizabethae, West Nile virus, Borellia recurrentis, lymphocytic choriomeningitis virus, Wohlfartiimonas chitiniclastica, Seoul hantavirus (SEOV), and Leptospira species was also identified in published studies, with SEOV associated with chronic renal disease later in life. HIV infection, injection drug use, and heavy drinking were noted across multiple studies as risk factors for infection with vector-borne and zoonotic pathogens.

CONCLUSIONS

B. quintana was the most frequently reported vector-borne infection identified in our article. Delousing efforts and active surveillance among HIV-positive individuals, who are at elevated risk of complication from B. quintana infection, are advised to reduce morbidity. Given documented exposure to rodent-borne zoonoses among urban homeless and marginalized people, reducing human contact with rodents remains an important public health priority.

Demographic characteristics and infectious diseases of a population of American black bears in Humboldt County, California

American black bears (Ursus americanus) are common, widely distributed, and broad-ranging omnivorous mammals in northern California forests. Bears may be susceptible to pathogens infecting both domestic animals and humans. Monitoring bear populations, particularly in changing ecosystems, is important to understanding ecological features that could affect bear population health and influence the likelihood that bears may cause adverse impacts on humans. In all, 321 bears were captured between May, 2001, and October, 2003, and blood samples were collected and tested for multiple zoonotic and vector-borne diseases. We found a PCR prevalence of 10% for Anaplasma phagocytophilum, and a seroprevalence of 28% for Toxoplasma gondii, 26% for Borrelia burgdorferi, 26% for A. phagocytophilum, 8% for Trichinella spiralis, 8% for Francisella tularensis and 1% for Yersinia pestis. In addition, we tested bears for pathogens of domestic dogs and found a seroprevalence of 15% for canine distemper virus and 0.6% for canine parvovirus. Our findings show that black bears can become infected with pathogens that are an important public health concern, as well as pathogens that can affect both domestic animals and other wildlife species.

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.

Did Bartonella henselae contribute to the deaths of two veterinarians?

Bartonella henselae, a flea-transmitted bacterium, causes chronic, zoonotic, blood stream infections in immunocompetent and immunocompromised patients throughout the world. As an intra-erythrocytic and endotheliotropic bacterium, B. henselae causes a spectrum of symptomatology ranging from asymptomatic bacteremia to fever, endocarditis and death. Veterinary workers are at occupational risk for acquiring bartonellosis. As an emerging, and incompletely understood, stealth bacterial pathogen, B. henselae may or may not have been responsible for the deaths of two veterinarians; however, recent evidence indicates that this genus is of much greater medical importance than is currently appreciated by the majority of the biomedical community.

Infections and cardiovascular disease: is Bartonella henselae contributing to this matter?

Cardiovascular disease is still the major cause of death worldwide despite the remarkable progress in its prevention and treatment. Endothelial progenitor cells (EPCs) have recently emerged as key players of vascular repair and regenerative medicine applied to cardiovascular disease. A large amount of effort has been put into discovering the factors that could aid or impair the number and function of EPCs, and also into characterizing these cells at the molecular level in order to facilitate their therapeutic applications in vascular disease. Interestingly, the major cardiovascular risk factors have been associated with reduced number and function of EPCs. The bacterial contribution to cardiovascular disease represents a long-standing controversy. The discovery that Bartonella henselae can infect and damage EPCs revitalizes the enduring debate about the microbiological contribution to atherosclerosis, thus allowing the hypothesis that this infection could impair the cardiovascular regenerative potential and increase the risk for cardiovascular disease. In this review, we summarize the rationale suggesting that Bartonella henselae could favour atherogenesis by infecting and damaging EPCs, thus reducing their vascular repair potential. These mechanisms suggest a novel link between communicable and non-communicable human diseases, and put forward the possibility that Bartonella henselae could enhance the susceptibility and worsen the prognosis in cardiovascular disease.

Bartonella quintana Aortitis in a Man with AIDS, Diagnosed by Needle Biopsy and 16S rRNA Gene Amplification

A man with newly diagnosed AIDS presented with months of back pain and fever. Computed tomography (CT) results demonstrated aortitis with periaortic tissue thickening. DNA amplification of biopsy tissue revealed Bartonella quintana, and Bartonella serologies were subsequently noted to be positive. The patient improved with prolonged doxycycline and rifabutin treatment. This case illustrates how molecular techniques are increasingly important in diagnosing Bartonella infections.

A case of feline systemic reactive angioendotheliomatosis

A 3-year-old domestic shorthair cat presented with lethargy and anorexia. A blood test showed regenerative anaemia and thrombocytopenia. Thoracic radiographs showed a small amount of pleural effusion. The cat did not respond to treatment and died on the fifth day. Necropsy revealed moderate pericardial effusion, and multifocal coalescing haemorrhages were observed on both atria. Histological analysis revealed that the most severe lesions were located on the heart. Numerous arterioles supplying the heart were partially to completely filled with plump spindle cells that often formed glomerulus-like arrangements within the lumen. Similar vascular proliferative lesions were also found in the liver, pancreas and kidney. Immunohistochemical analysis showed that these intraluminal proliferative spindle cells were positive for anti-von Willebrand factor (vWF). Strongly positive antismooth muscle actin staining was observed at the periphery of these intraluminal proliferations (comprising arteriolar smooth muscle) and certain intraluminal cells (pericytes). The intraluminal thrombi were also positive for vWF. Those thrombi were confirmed as platelet thrombi by phosphotungstic acid haematoxylin and Masson’s trichrome staining. These results were consistent with feline systemic reactive angioendotheliomatosis.

Bite injuries to the hand: microbiology, virology and management

Bites to the human hand, be it from a pet, a stray animal or even a fellow human, may often have dire consequences for the person suffering the insult. Bites by mammals are a common problem and they account for up to 1% of all visits to hospital emergency rooms, in the UK. Clenched fist injuries to the mouth ('fight bite') are notorious for being the worst human bites. Bite injuries of the hand and their related infections must be monitored vigilantly and managed proactively, by experts in this field of surgery. In this review article we discuss the associated microbiology and virology of these injuries as well as their management.

Pathology of the liver sinusoids

The hepatic sinusoids comprise a complex of vascular conduits to transport blood from the porta hepatis to the inferior vena cava through the liver. Under normal conditions, portal venous and hepatic artery pressures are equalized within the sinusoids, oxygen and nutrients from the systemic circulation are delivered to the parenchymal cells and differentially distributed throughout the liver acini, and proteins of liver derivation are carried into the cardiac/systemic circulation. Liver sinusoid structures are lined by endothelial cells unique to their location, and Kupffer cells. Multifunctional hepatic stellate cells and various immune active cells are localized within the space of Disse between the sinusoid and the adjacent hepatocytes. Flow within the sinusoids can be compromised by physical or pressure blockage in their lumina as well as obstructive processes within the space of Disse. The intimate relationship of the liver sinusoids to neighbouring hepatocytes is a significant factor affecting the health of hepatocytes, or transmission of the effects of injury within the sinusoidal space. Pathologists should recognize several patterns of injury involving the sinusoids and surrounding hepatocytes. In this review, injury, alterations and accumulations within the liver sinusoids are illustrated and discussed.

Does bacterial infection cause genome instability and cancer in the host cell?

Research of the past several decades suggests that bacterial infection can lead to genome instability of the host cell often resulting in cancer development. However, there is still a substantial lack of knowledge regarding possible mechanisms involved in the development of genomic instability. Several questions remain unanswered, namely: Why has the causative relationship between the bacterial infection and cancer been established only for a small number of cancers? What is the mechanism responsible for the induction of genome instability and cancer? Is the infection process required to cause genome instability and cancer? In this review, we present a hypothesis that the bacterial infection, exposure to heat-killed bacteria or even some bacterial determinants may trigger genome instability of exposed and distal cells, and thus may cause cancer. We will discuss the mechanisms of host responses to the bacterial infection and present the possible pathways leading to genome instability and cancer through exposure to bacteria.

Fatal hepatic hemorrhage by peliosis hepatis in X-linked myotubular myopathy: a case report

We report a 5-year-old boy with X-linked myotubular myopathy complicated by peliosis hepatis. At birth, he was affected with marked generalized muscle hypotonia and weakness, which required permanent ventilatory support, and was bedridden for life. He died of acute fatal hepatic hemorrhage after using a mechanical in-exsufflator. Peliosis hepatis, defined as multiple, variable-sized, cystic blood-filled spaces through the liver parenchyma, was confirmed by autopsy. To avoid fatal hepatic hemorrhage by peliosis hepatis, routine hepatic function tests and abdominal imaging tests should be performed for patients with X-linked myotubular myopathy, especially at the time of using artificial respiration.

Transmission and maintenance cycle of Bartonella quintana among rhesus macaques, China

We detected Bartonella quintana in 48.6% of captive rhesus macaques from an animal facility in Beijing, China. Prevalence of infection increased over the period of observation. Our findings suggest that macaques may serve as reservoir hosts for B. quintana and that Pedicinus obtusus lice might act as efficient vectors.

Bacteria-human somatic cell lateral gene transfer is enriched in cancer samples

There are 10× more bacterial cells in our bodies from the microbiome than human cells. Viral DNA is known to integrate in the human genome, but the integration of bacterial DNA has not been described. Using publicly available sequence data from the human genome project, the 1000 Genomes Project, and The Cancer Genome Atlas (TCGA), we examined bacterial DNA integration into the human somatic genome. Here we present evidence that bacterial DNA integrates into the human somatic genome through an RNA intermediate, and that such integrations are detected more frequently in (a) tumors than normal samples, (b) RNA than DNA samples, and (c) the mitochondrial genome than the nuclear genome. Hundreds of thousands of paired reads support random integration of Acinetobacter-like DNA in the human mitochondrial genome in acute myeloid leukemia samples. Numerous read pairs across multiple stomach adenocarcinoma samples support specific integration of Pseudomonas-like DNA in the 5′-UTR and 3′-UTR of four proto-oncogenes that are up-regulated in their transcription, consistent with conversion to an oncogene. These data support our hypothesis that bacterial integrations occur in the human somatic genome and may play a role in carcinogenesis. We anticipate that the application of our approach to additional cancer genome projects will lead to the more frequent detection of bacterial DNA integrations in tumors that are in close proximity to the human microbiome.

There are 10× more bacterial cells in the human body than there are human cells that are part of the human microbiome. Many of those bacteria are in constant, intimate contact with human cells. We sought to establish if bacterial cells insert their own DNA into the human genome. Such random mutations could cause disease in the same manner that mutagens like UV rays from the sun or chemicals in cigarettes induce mutations. We detected the integration of bacterial DNA in the human genome more readily in tumors than normal samples. In particular, extensive amounts of DNA with similarity to Acinetobacter DNA were fused to human mitochondrial DNA in acute myeloid leukemia samples. We also identified specific integrations of DNA with similarity to Pseudomonas DNA near the untranslated regulatory regions of four proto-oncogenes. This supports our hypothesis that bacterial integrations occur in the human somatic genome that may potentially play a role in carcinogenesis. Further study in this area may provide new avenues for cancer prevention.