Case Report: Role of Point-of-Care Ultrasound in the Diagnosis of Bacillary Angiomatosis.

Clinical skin manifestations are commonly seen in resource-limited settings, but they are frequently misdiagnosed due to the lack of microbiological tests with ensuing stigma and long-term disability. The adoption of portable ultrasound devices, which extend physical examination in the hands of trained clinicians, has partially improved the situation. Specific protocols, such as focused assessment with sonography for HIV-associated tuberculosis (FASH), have led to simplified diagnostic pathways. Here we describe a case of bacillary angiomatosis in a patient with advanced HIV disease presenting with subacute unusual cutaneous lesions. The patient also presented with significant weight loss, anemia, and prostration. Highly sensitive rapid tests for tuberculosis and cryptococcosis were negative, and CD4 count was very low. Ultrasound scanning (US) and biopsy of the cutaneous lesions finally led to diagnosis and treatment. This report illustrates the benefits of integrating ultrasound-based protocols with clinical skills, as the diagnosis was suspected based on clinical presentation and US and confirmed by pathology. The importance of adoption of US protocols by infectious diseases clinicians is discussed.

The autotransporter BafA contributes to the proangiogenic potential of Bartonella elizabethae.

Bartonella elizabethae is a rat-borne zoonotic bacterium that causes human infectious endocarditis or neuroretinitis. Recently, a case of bacillary angiomatosis (BA) resulting from this organism was reported, leading to speculation that B. elizabethae may also trigger vasoproliferation. However, there are no reports of B. elizabethae promoting human vascular endothelial cell (EC) proliferation or angiogenesis, and to date, the effects of this bacterium on ECs are unknown. We recently identified a proangiogenic autotransporter, BafA, secreted from B. henselae and B. quintana, which are recognized as Bartonella spp. responsible for BA in humans. Here, we hypothesized that B. elizabethae also harbored a functional bafA gene and examined the proangiogenic activity of recombinant B. elizabethae-derived BafA. The bafA gene of B. elizabethae, which was found to share a 51.1% amino acid sequence identity with BafA of B. henselae and 52.5% with that of B. quintana in the passenger domain, was located in a syntenic region of the genome. The recombinant protein of the N-terminal passenger domain of B. elizabethae-BafA facilitated EC proliferation and capillary structure formation. Furthermore, it upregulated the receptor signaling pathway of vascular endothelial growth factor, as observed in B. henselae-BafA. Taken together, B. elizabethae-derived BafA stimulates human EC proliferation and may contribute to the proangiogenic potential of this bacterium. So far, functional bafA genes have been found in all BA-causing Bartonella spp., supporting the key role BafA may play in BA pathogenesis.

Detection of Bartonella vinsonii subsp. berkhoffii in an HIV patient using metagenomic Next-Generation Sequencing.

Bartonella species are fastidious, aerobic bacteria that are transmitted by blood-sucking arthropods. Bartonella spp. are responsible for cat scratch disease, Carrion's disease, bacillary angiomatosis and trench fever. On the other hand, Bartonella vinsonii is rarely reported in the literature and there exist a few reports of systemic infection caused by Bartonella vinsonii in patients with acquired immunodeficiency syndrome. A 31-year-old male (diagnosed with AIDS six years ago) had persistent fever and ulceration in the right knee. The elevated levels of inflammatory markers suggested an infectious aetiology. Despite the negative findings of blood culture, metagenomic Next-Generation Sequencing of plasma detected Bartonella vinsonii. The polymerase chain reaction of whole blood and Sanger sequencing confirmed the mNGS findings. Immunohistochemical staining had later suggested bacillary angiomatosis, which was consistent with Bartonella infection. Following antibiotic treatment, the ulcers subsided significantly, but a high fever persisted. The patient died due to sudden respiratory failure.

Bartonella henselae Persistence within Mesenchymal Stromal Cells Enhances Endothelial Cell Activation and Infectibility That Amplifies the Angiogenic Process.

Some bacterial pathogens can manipulate the angiogenic response, suppressing or inducing it for their own ends. In humans, Bartonella henselae is associated with cat-scratch disease and vasculoproliferative disorders such as bacillary angiomatosis and bacillary peliosis. Although endothelial cells (ECs) support the pathogenesis of B. henselae, the mechanisms by which B. henselae induces EC activation are not completely clear, as well as the possible contributions of other cells recruited at the site of infection. Mesenchymal stromal cells (MSCs) are endowed with angiogenic potential and play a dual role in infections, exerting antimicrobial properties but also acting as a shelter for pathogens. Here, we delved into the role of MSCs as a reservoir of B. henselae and modulator of EC functions. B. henselae readily infected MSCs and survived in perinuclearly bound vacuoles for up to 8 days. Infection enhanced MSC proliferation and the expression of epidermal growth factor receptor (EGFR), Toll-like receptor 2 (TLR2), and nucleotide-binding oligomerization domain-containing protein 1 (NOD1), proteins that are involved in bacterial internalization and cytokine production. Secretome analysis revealed that infected MSCs secreted higher levels of the proangiogenic factors vascular endothelial growth factor (VEGF), fibroblast growth factor 7 (FGF-7), matrix metallopeptidase 9 (MMP-9), placental growth factor (PIGF), serpin E1, thrombospondin 1 (TSP-1), urokinase-type plasminogen activator (uPA), interleukin 6 (IL-6), platelet-derived growth factor D (PDGF-D), chemokine ligand 5 (CCL5), and C-X-C motif chemokine ligand 8 (CXCL8). Supernatants from B. henselae-infected MSCs increased the susceptibility of ECs to B. henselae infection and enhanced EC proliferation, invasion, and reorganization in tube-like structures. Altogether, these results indicate MSCs as a still underestimated niche for persistent B. henselae infection and reveal MSC-EC cross talk that may contribute to exacerbate bacterium-induced angiogenesis and granuloma formation.

Bacillary Angiomatosis in Renal Transplant Recipient: A Case Report.

INTRODUCTION: Bacillary angiomatosis (BA) is a rare, opportunistic infectious disease caused by the aerobic Gram-negative bacilli Bartonella henselae or Bartonella quintana. The main reservoir for those microbes are cats. The disease mostly affects immunocompromised patients with human immunodeficiency virus infection, after organ transplantation, undergoing corticosteroid and methotrexate therapy or with oncological history. CASE REPORT: We represent the case of a 65-year-old man who reported to the Department of Dermatology with a high fever and numerous nodular skin lesions on the 5th month of kidney transplantation. At that time, his immunosuppressive therapy consisted of tacrolimus 6 mg/day, mycophenolate mofetil 2 g/day, and prednisone 5 mg/day. Laboratory tests revealed an increased leukocyte count and elevated values of acute-phase proteins, but blood cultures were negative. Skin biopsy was performed and BA was diagnosed. The patient was given oral doxycycline 100 mg twice a day. During antibiotic therapy, his body temperature normalized and skin lesions began to resolve. The patient continued the above treatment for the next 3 months with good tolerance, and no relapse occurred in 1 year. CONCLUSION: BA should be listed among possible opportunistic infections in organ transplant recipients.

First Report of Bacillary Angiomatosis by Bartonella elizabethae in an HIV-Positive Patient.

We present the case of an HIV-positive patient who developed polymorphous lesions in which the evidence in the skin biopsy corresponds to the diagnosis of bacillary angiomatosis, and further tests proved the pathological agent involved in this case is not the usual Bartonella species, B. henselae and B. quintana, but B. elizabethae. As far as we know, this is the first case of bacillary angiomatosis secondary to this etiological agent.

Bartonella henselae in small Indian mongooses (Herpestes auropunctatus) from Grenada, West Indies.

Many mammals are established hosts for the vector borne bacterial genus, Bartonella. Small Indian mongooses (Herpestes auropunctatus) have only been reported as a possible host for Bartonella henselae in southern Japan. Confirming Bartonella presence in mongooses from other regions in the world may support their role as potential reservoirs of this human pathogen. Specifically, documenting Bartonella in Caribbean mongooses would identify a potential source of zoonotic risk with mongoose-human contact in the New World. Using serological and molecular techniques, we investigated B. henselae DNA and specific antibody prevalence in 171 mongooses from all six parishes in Grenada, West Indies. Almost a third (32.3%, 54/167) of the tested mongooses were B. henselae seropositive and extracted DNA from 18/51 (35.3%) blood pellets were PCR positive for the citrate synthase (gltA) and/or the ß subunit of RNA polymerase (rpoB) genes. All sequences were identical to B. henselae genotype I, as previously reported from Japan. This study confirms the role of small Indian mongooses as a natural reservoir of B. henselae in the New World.

Infections by pathogens with different transmission modes in feral cats from urban and rural areas of Korea.

In this study, we examine prevalences of three infectious pathogens with different transmission modes (Bartonella henselae, hemoplasma, and Toxoplasma gondii) in feral cats from urban and rural habitats. Infection status of the three pathogens in blood samples (n = 117) was determined through molecular or serological diagnostic methods. Overall prevalence of hemoplasma, Toxoplasma gondii, and Bartonella henselae was 47.9%, 50%, and 35.7%, respectively. Comparing the two habitats, only seroprevalence of Bartonella henselae was significantly higher in urban cats. Based on the results, we discuss how pathogens with distinct transmission modes may show different prevalence between urban and rural habitat types.

The Conjugative Relaxase TrwC Promotes Integration of Foreign DNA in the Human Genome.

Bacterial conjugation is a mechanism of horizontal DNA transfer. The relaxase TrwC of the conjugative plasmid R388 cleaves one strand of the transferred DNA at the oriT gene, covalently attaches to it, and leads the single-stranded DNA (ssDNA) into the recipient cell. In addition, TrwC catalyzes site-specific integration of the transferred DNA into its target sequence present in the genome of the recipient bacterium. Here, we report the analysis of the efficiency and specificity of the integrase activity of TrwC in human cells, using the type IV secretion system of the human pathogen Bartonella henselae to introduce relaxase-DNA complexes. Compared to Mob relaxase from plasmid pBGR1, we found that TrwC mediated a 10-fold increase in the rate of plasmid DNA transfer to human cells and a 100-fold increase in the rate of chromosomal integration of the transferred DNA. We used linear amplification-mediated PCR and plasmid rescue to characterize the integration pattern in the human genome. DNA sequence analysis revealed mostly reconstituted oriT sequences, indicating that TrwC is active and recircularizes transferred DNA in human cells. One TrwC-mediated site-specific integration event was detected, proving that TrwC is capable of mediating site-specific integration in the human genome, albeit with very low efficiency compared to the rate of random integration. Our results suggest that TrwC may stabilize the plasmid DNA molecules in the nucleus of the human cell, probably by recircularization of the transferred DNA strand. This stabilization would increase the opportunities for integration of the DNA by the host machinery.IMPORTANCE Different biotechnological applications, including gene therapy strategies, require permanent modification of target cells. Long-term expression is achieved either by extrachromosomal persistence or by integration of the introduced DNA. Here, we studied the utility of conjugative relaxase TrwC, a bacterial protein with site-specific integrase activity in bacteria, as an integrase in human cells. Although it is not efficient as a site-specific integrase, we found that TrwC is active in human cells and promotes random integration of the transferred DNA in the human genome, probably acting as a DNA chaperone until it is integrated by host mechanisms. TrwC-DNA complexes can be delivered to human cells through a type IV secretion system involved in pathogenesis. Thus, TrwC could be used in vivo to transfer the DNA of interest into the appropriate cell and promote its integration. If used in combination with a site-specific nuclease, it could lead to site-specific integration of the incoming DNA by homologous recombination.

Simultaneous Detection of Dual Nucleic Acids Using a SERS-Based Lateral Flow Assay Biosensor.

A new class of surface-enhanced Raman scattering (SERS)-based lateral flow assay (LFA) biosensor has been developed for the simultaneous detection of dual DNA markers. The LFA strip in this sensor was composed of two test lines and one control line. SERS nano tags labeled with detection DNA probes were used for quantitative evaluation of dual DNA markers with high sensitivity. Target DNA, associated with Kaposi's sarcoma-associated herpesvirus (KSHV) and bacillary angiomatosis (BA), were tested to validate the detection capability of this SERS-based LFA strip. Characteristic peak intensities of SERS nano tags on two test lines were used for quantitative evaluations of KSHV and BA. The limits of detection for KSHV and BA, determined from our SERS-based LFA sensing platform, were estimated to be 0.043 and 0.074 pM, respectively. These values indicate approximately 10 000 times higher sensitivity than previously reported values using the aggregation-based colorimetric method. We believe that this is the first report of simultaneous detection of two different DNA mixtures using a SERS-based LFA platform. This novel detection technique is also a promising multiplex DNA sensing platform for early disease diagnosis.

A family of genus-specific RNAs in tandem with DNA-binding proteins control expression of the badA major virulence factor gene in Bartonella henselae.

Bartonella henselae is a gram-negative zoonotic bacterium that causes infections in humans including endocarditis and bacillary angiomatosis. B. henselae has been shown to grow as large aggregates and form biofilms in vitro. The aggregative growth and the angiogenic host response requires the trimeric autotransporter adhesin BadA. We examined the transcriptome of the Houston-1 strain of B. henselae using RNA-seq revealing nine novel, highly-expressed intergenic transcripts (Bartonella regulatory transcript, Brt1-9). The Brt family of RNAs is unique to the genus Bartonella and ranges from 194 to 203 nucleotides with high homology and stable predicted secondary structures. Immediately downstream of each of the nine RNA genes is a helix-turn-helix DNA-binding protein (transcriptional regulatory protein, Trp1-9) that is poorly transcribed under the growth conditions used for RNA-seq. Using knockdown or overexpressing strains, we show a role of both the Brt1 and Trp1 in the regulation of badA and also in biofilm formation. Based on these data, we hypothesize that Brt1 is a trans-acting sRNA that also serves as a cis-acting riboswitch to control the expression of badA. This family of RNAs together with the downstream Trp DNA-binding proteins represents a novel coordinated regulatory circuit controlling expression of virulence-associated genes in the bartonellae.

Bacillary angiomatosis presenting with facial tumor and multiple abscesses: A case report.

BACKGROUND: The clinical manifestation of bacillary angiomatosis (BA) can be limited to one organ, most commonly the skin, but systemic courses can also occur. We report a human immunodeficiency virus (HIV)-positive patient with a systemic manifestation of BA caused by Bartonella quintana, diagnosed in Vienna, Austria. The pathogen was detected in multiple organs including a facial tumor which is an unusual finding for BA. Furthermore, infections with B quintana are rare in our area and no other autochthonous cases have been reported. METHODS AND RESULTS: The clinical manifestation included multiple papules and nodules on the entire body, several organic abscesses, and a facial tumor influencing the patient's view.The main laboratory finding indicated HIV infection combined with severe immunosuppression with 47 CD4 cells/µL. Contrast-enhanced computed tomography of the chest and the abdomen showed multiple and abscesses. Histological examination of the facial tumor confirmed inflammatory process. Bartonella quintana was detected by PCR in blood and in the facial tumor as well as by culture in the skin tissue. Antibiotic treatment with doxycycline and antiretroviral therapy resulted in clinical improvement. CONCLUSION: Our case shows that rare opportunistic, vector-borne infections, usually associated with poverty, can lead to diagnosis of HIV even in well-developed countries. Furthermore, we provide details on clinical manifestation and diagnostic work-up which might expand the knowledge on disseminated infections with B quintana. As far, tumorous deformations have rarely been reported as consequence of BA. In our patient the pathogen was detected in the facial tumor using PCR techniques.

Similar presentation of cervical lymphadenitis of different etiology in two siblings.

Here, we report chronic suppurating submandibular swelling occurring in two siblings, with one case caused by nontuberculous mycobacteria and the other caused by Bartonella henselae. These two infections share a similar clinical presentation, but the treatment modalities differed.

Infectious Angiogenesis-Different Pathways, the Same Goal.

Infectious angiogenesis is the biological response of neoangiogenesis induced by infectious organisms. The authors present 3 exemplary entities which show paradigmatic clinico-pathological settings of infectious angiogenesis: Bacillary angiomatosis, Orf (ecthyma contagiosum), and Kaposi sarcoma. The authors review the literature and elucidate etiopathogenetic pathways leading to the phenomenon of neovascularization stimulated by infectious organisms. The authors describe the clinical and histological pictures, interactions between microorganisms and host cells, and changes that occur within cellular structures, as well as angiogenic factors that underpin infectious angiogenesis. The importance of chronic inflammation and tumor angiogenesis is emphasized.

Broadening the Morphologic Spectrum of Bartonella henselae Lymphadenitis: Analysis of 100 Molecularly Characterized Cases.

Bartonella henselae lymphadenitis, or cat-scratch lymphadenitis (CSL), is classically associated with stellate microabscesses, occasional giant cells, and extension of the inflammatory infiltrate into perinodal soft tissue. Availability of B. henselae molecular testing on tissue specimens has broadened our understanding of the morphologic variation in this disease. Here we sought to describe the histopathologic features of the largest series to date of molecularly proven CSL. B. henselae polymerase chain reaction-positive tissue specimens from 2010 to 2012 were identified, and hematoxylin and eosin slides were reviewed. A single-step 16S-23S rRNA-based polymerase chain reaction testing was used to identify B. henselae on formalin-fixed, paraffin-embedded tissues. A total of 100 B. henselae-positive cases were identified. The median age of the patients was 26.5 years (range, 1 to 69 y). Ninety-two percent of cases presented in lymph nodes, with 66% of these occurring above the diaphragm, most commonly in the cervical chain. Of 100 cases, 57 had classical CSL features of necrotizing granulomas with microabscesses, with or without surrounding palisading histiocytes. In contrast, 43/100 cases lacked the prototypical microabscesses of CSL including: 23 cases (53.5%) with features of fungal/mycobacterial lymphadenitis, 6 (14%) cases with features of Kikuchi lymphadenitis, and 4 cases (9.3%) with the classic histologic triad of toxoplasma lymphadenitis. In summary, B. henselae lymphadenitis may lack the typical microabscesses in almost half of cases and may closely mimic other reactive, especially infectious, lymphadenopathies. Given the lack of specificity of many of these features, a low threshold for B. henselae molecular testing on tissue is warranted in the appropriate clinical context.

Analysis of Endothelial Adherence of Bartonella henselae and Acinetobacter baumannii Using a Dynamic Human Ex Vivo Infection Model.

Bacterial adherence determines the virulence of many human-pathogenic bacteria. Experimental approaches elucidating this early infection event in greater detail have been performed using mainly methods of cellular microbiology. However, in vitro infections of cell monolayers reflect the in vivo situation only partially, and animal infection models are not available for many human-pathogenic bacteria. Therefore, ex vivo infection of human organs might represent an attractive method to overcome these limitations. We infected whole human umbilical cords ex vivo with Bartonella henselae or Acinetobacter baumannii under dynamic flow conditions mimicking the in vivo infection situation of human endothelium. For this purpose, methods for quantifying endothelium-adherent wild-type and trimeric autotransporter adhesin (TAA)-deficient bacteria were set up. Data revealed that (i) A. baumannii binds in a TAA-dependent manner to endothelial cells, (ii) this organ infection model led to highly reproducible adherence rates, and furthermore, (iii) this model allowed to dissect the biological function of TAAs in the natural course of human infections. These findings indicate that infection models using ex vivo human tissue samples ("organ microbiology") might be a valuable tool in analyzing bacterial pathogenicity with the capacity to replace animal infection models at least partially.