Unmasking Bartonella henselae infection in the shadows of long COVID thanks to clinical metagenomics.

The diagnosis of long COVID often relies on symptoms post-COVID-19, occasionally lacking biological evidence. This case study illustrates how investigating long COVID uncovered an underlying bartonellosis through clinical metagenomics. Following mild COVID-19, a 26-year-old woman experienced persistent symptoms during 5 months, including axillary adenopathy. Pathological examination, 16 S rRNA PCR, and clinical metagenomic analysis were done on an adenopathy biopsy. The latter revealed Bartonella henselae DNA and RNA. Treatment with clarithromycin improved symptoms. This case underscores the relevance of clinical metagenomics in diagnosing hidden infections. Post-COVID symptoms warrant thorough investigation, and bartonellosis should be considered in polyadenopathy cases, regardless of a recent history of cat or flea exposures.

Post-COVID reactivation of latent Bartonella henselae infection: a case report and literature review.

Cat scratch disease (CSD) is caused by Bartonella henselae (B. henselae) and presents as lymphadenopathy following close contact with cats. However, in context of the global COVID-19 pandemic, clinical manifestations of CSD may vary, posing new challenges for healthcare professionals. Here we describe a case of a 54-year-old male with painful left upper arm mass, which gradually resolved until he was infected with COVID-19. The mass then rapidly progressed before admission. Meanwhile, pulmonary symptoms including pleural effusion emerged simultaneously. The cause was undetermined with routine blood culture and pathological test until the next generation sequencing (NGS) confirmed the presence of B. henselae. We believe this case is the first to report localized aggravation of CSD after COVID-19 infection and hopefully, offers treatment experience for clinicians worldwide.

Bartonella henselae Infection and Lymphadenopathy in a Patient With T Cell Acute Lymphoblastic Leukemia.

Patients undergoing therapy for T cell acute lymphoblastic leukemia are at risk of infections during their treatment course. Cat scratch disease caused by Bartonella hensalae can masquerade as leukemic relapse and cause systemic infection. Obtaining a thorough exposure history may aid clinicians in making the diagnosis.

Comparison of Biological Activities of BafA Family Autotransporters within Bartonella Species Derived from Cats and Rodents.

Bartonella species are hemotropic, facultative intracellular bacteria, some of which cause zoonoses, that are widely disseminated among many mammals, including humans. During infection in humans, vascular endothelial cells play a crucial role as a replicative niche for Bartonella, and some are capable of promoting vascular proliferation. Along with well-studied pathogenic factors such as a trimeric autotransporter adhesin BadA or VirB/D4 type IV secretion system, bacteria-secreted protein BafA is also involved in Bartonella-induced vasoproliferation. Genes encoding BafA orthologs have been found in the genomes of most Bartonella species, but their functionality remains unclear. In this study, we focused on three cat-derived zoonotic species (B. henselae, B. koehlerae, and B. clarridgeiae) and two rodent-derived species (B. grahamii and B. doshiae) and compared the activity of BafA derived from each species. Recombinant BafA proteins of B. henselae, B. koehlerae, B. clarridgeiae, and B. grahamii, species that also cause human disease, induced cell proliferation and tube formation in cultured endothelial cells, while BafA derived from B. doshiae, a species that is rarely found in humans, showed neither activity. Additionally, treatment of cells with these BafA proteins increased phosphorylation of both vascular endothelial growth factor receptor 2 and extracellular signal-regulated kinase 1/2, with the exception of B. doshiae BafA. Differential bafA mRNA expression and BafA secretion among the species likely contributed to the differences in the cell proliferation phenotype of the bacteria-infected cells. These findings suggest that the biological activity of BafA may be involved in the infectivity or pathogenicity of Bartonella species in humans.

Bartonella spp. Infections Identified by Molecular Methods, United States.

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

Autoimmune Thyroiditis Induced by Bartonella henselae (Cat-Scratch Disease) Might Be Reversible.

INTRODUCTION: Bartonella henselae infection leads to development of cat-scratch disease (CSD) but may also trigger of autoimmune thyroiditis (AIT). CASE PRESENTATION: We describe a 4-year-old boy with a severe fever of unknown etiology, disseminated neck lymphadenopathy, and a headache. Treatment with antibiotics was employed, but finally a left tonsillectomy, selective left lymphadenectomy, and immunophenotyping were performed to exclude lymphoma. Histologic examination excluded lymphoma but revealed CSD. IgG against B. henselae and Bartonella quintana was positive. A goiter was also found and positive anti-thyroid antibodies confirmed AIT. Two months later, the thyroid was not palpable, normal on ultrasound, and both anti-thyroid antibodies were negative. The full reversibility was documented, and 6-year follow-up showed that the patient remains disease free. CONCLUSION: This is the first report that AIT triggered by B. henselae/B. qunitana might be reversible if the pathogenetic factor is eliminated at an early stage of disease.

Genetic characterization of Bartonella henselae samples isolated from stray cats by multi-locus sequence typing.

BACKGROUND: Bartonella henselae is one of the most commonly identified Bartonella species associated with several human diseases. Although B. henselae was detected in humans and cats in Turkey, they have not been genotyped previously. Therefore, this study aimed to genotype B. henselae samples (n = 44) isolated from stray cats using the multi-locus sequence typing (MLST) method. For this aim, eight different housekeeping markers were amplified by nested PCR and then sequenced to reveal sequence types (STs) of B. henselae samples. RESULTS: Allelic profiles obtained from 40 B. henselae isolates (90.9%) were compatible with available allelic profiles in the MLST online database. However, allelic profiles obtained from the remaining 4 B. henselae isolates (9.1%) were incompatible with the database. Among B. henselae isolates with compatible allelic profiles, 5 different STs including ST1, ST5, ST9, ST35 and ST36 were identified according to the B. henselae MLST online database. ST35 was the most prevalent ST with a prevalence rate of 29.5% (13/44), followed by ST36 with a prevalence rate of 22.7% (10/44). In addition, ST5 (16%, 7/44) and ST9 (18.2%, 8/44) were also among the prevalent STs. The prevalence of ST1 was 4.5% (2/44). For B. henselae isolates with incompatible allelic profiles, we recommended a new ST called ST38. CONCLUSION: The present study genotyped B. henselae samples isolated from stray cats in Turkey for the first time and ST1, ST5, ST9, ST35, and ST36 as well as a new sequence type named ST38 were identified among these B. henselae isolates.

Cat-scratch disease manifesting as uveitis and binocular fundus nodular lesions: a case report.

BACKGROUND: Cat-scratch disease typically presents with various ocular manifestations such as uveitis, vitritis, retinitis, retinochoroiditis, and optic neuritis. However, fundus nodular lesions was rarely reported. In our study, we reported a case of Cat-Scratch disease with binocular fundus nodular lesions. CASE PRESENTATION: An 11-year old male presented with uveitis in the right eye and bilateral fundus nodular lesions after indirect contact with unvaccinated cats. Comprehensive ancillary examinations including wide-angle fundus photography, ultrasonography, fluorescein fundus angiography, optical coherence tomography, and orbital magnetic resonance imaging were performed to elucidate the multidimensional features of the binocular lesions. Metagenomics next-generation sequencing was utilized to confirm the diagnosis of Cat-scratch disease. The patient's condition showed improvement after a 6-month combination treatment regimen involving systemic administration of doxycycline hyclate and methylprednisolone tablets, as well as local application of mydriatic and corticosteroid eye drops. CONCLUSIONS: We firstly reported a case of Cat-scratch disease presenting simultaneously with uveitis and fundus nodular lesions caused by Bartonella henselae infection in a child. Timely diagnosis and treatment with antibiotics and corticosteroids showed promising outcomes for the prognosis of these ocular disorders.

Into the unknown: Diagnosing mysterious brain lesions.

In this inaugural clinicopathological conference, the invited experts discussed the diagnostic approach to central nervous system infections in immunocompromised hosts. The case presented involved a pancreas-kidney transplant recipient with multiple brain abscesses caused by Bartonella henselae. CSF metagenomic next-generation sequencing played a significant role in the diagnosis. Bartonella henselae is a gram-negative zoonotic pathogen that causes cat-scratch disease, which can be transmitted to humans through cat bites or scratches. Symptoms can vary in severity, correlating with the patient's immune status. Visceral organ involvement, ocular involvement, and neurological manifestations have been reported in immunocompromised patients, but brain abscesses are rare.

In silico analyses and design of chimeric proteins containing epitopes of Bartonella henselae antigens for the control of cat scratch disease.

Bartonella henselae is a Gram-negative bacterium that causes cat scratch disease (CSD), as well as bacteremia, endocarditis, and other clinical presentations. CSD remains one of the most common infections caused by bacteria in the genus Bartonella, and it is transmitted to humans through a scratch or cat bite. Vaccination and more efficient diagnostic methods would represent a promising and sustainable alternative measure for CSD control in humans and animals. Here, we described the in silico analyses and design of three recombinant chimeric proteins (rC1, rC2, and rC3), for use in the control of CSD. The chimeras were constructed with epitopes identified from the sequences of the GroEL, 17 kDa, P26, BadA, Pap31, OMP 89, and OMP 43, previously described as the most important B. henselae antigens. The rC1, rC2, and rC3 were expressed and purified using a heterologous system based on Escherichia coli and reacted with antibodies present in the sera of humans naturally infected. The chimeric proteins were used to immunize mice using Freund adjuvant, and the humoral immune response was evaluated. Animals immunized with rC1 and rC3 showed a significant IgG antibodies response from the 28th day (P < 0.05), and the animals immunized with the rC2 from the 35th day (P < 0.05) remained until the 56th day of experimentation, with a titer of 1:3200 (P < 0.05), 1:1600 (P < 0.05) and 1:1600 (P < 0.05) from rC1, rC2, and rC3, respectively. Significant production of IgA and IgG1 isotype was detected in animals immunized with rC1 and rC2 proteins. Additionally, analysis using 13 serum samples from naturally infected patients showed that the proteins are recognized by antibodies present in sera, reinforcing the possibility of using these chimeras for CSD control. KEY POINTS: • The recombinant chimeras were expressed in Escherichia coli with 37 kDa (rC1), 35 kDa (rC2), and 38 kDa (rC3). • Animals immunized with rC1, rC2, and rC3 showed significant antibody response. • The chimeras were recognized by the sera of naturally infected patients.

Exploring the seasonal and regional features of cat-scratch disease on the basis of anti-Bartonella henselae IgM/IgG positive rates in Japan.

OBJECTIVES: This study aimed to explore the seasonal and regional features of cat-scratch disease (CSD) based on 15-years of test results for anti-Bartonella henselae IgG and IgM by immunofluorescence assay (IFA) performed as a laboratory specialized in diagnostic testing of CSD in Japan. A literature search was performed to put our findings in perspective. METHODS: A total of 956 sera from patients suspected of CSD were submitted to our laboratory from nationwide. Seasonal changes in the monthly positive rates of IgG/IgM antibodies and regional distribution of the test specimens were analyzed. RESULTS: The monthly positive rates of anti-B. henselae IFA of IgG and IgM were both significantly high between September and January and low between March and July. The seasonal pattern observed in this study was similar to the ones reported from US and France, which were analyzed from a clinical database (monthly incidence of CSD diagnosis) or from monthly positive rates of either B. henselae PCR or anti-B. henselae IFA. However, fluctuations in the IFA monthly positive rates in this study were more pronounced than other reports. Regarding regionality, the test specimens submitted to us for IFA were prominently more from southwestern areas than from northern/middle-northern areas of Japan. The distribution coincided well with the regional distribution of CSD case reports and with a known regional prevalence of Bartonella-species bacteremia among pet cats in Japan. CONCLUSION: These epidemiological features in Japan are of relevance in the clinical diagnoses of CSD.

Clinical utility of whole body diffusion-weighted imaging in an immunocompetent adult with atypical cat scratch disease.

BACKGROUND: Cat scratch disease (CSD) is an infectious disease caused by Bartonella henselae. CSD follows a typical course, characterized by regional lymphadenopathy. In atypical CSD, the lesions spread to systemic organs and can cause fever of unknown origin (FUO). A previous study showed the usefulness of whole-body magnetic resonance imaging (WB-MRI) with diffusion-weighted imaging (DWI) for limited areas in the diagnosis of FUO, but there are no studies on the clinical utility of whole-body DWI (WB-DWI). We herein report the case of an immunocompetent young man in whom contrast-enhanced CT-unidentifiable multiple liver abscess and osteomyelitis were successfully detected by WB-DWI. Follow-up with a liver biopsy helped confirm an atypical CSD diagnosis. CASE PRESENTATION: A 23-year-old previously healthy man was admitted for a 19-day history of high fever despite 3-day treatment by azithromycin. His physical examination was unremarkable and contrast-enhanced CT showed only a low attenuated area in the right lobe of the liver, indicating a cyst. WB-DWI revealed multiple nodular lesions of hypo-diffusion in the liver, spine, and pelvic region. The biopsy specimens of the liver abscess showed no evidence of tuberculosis/malignancy and the polymerase chain reaction (PCR) test of liver abscess aspirate showed positive findings for Bartonellahenselae, confirming the diagnosis of CSD. He completed minocycline monotherapy for a total of 60 days without any deterioration. CONCLUSIONS: WB-DWI can be useful for the diagnosis of atypical CSD with hepatic and bone involvement, which can cause FUO in young immunocompetent adults.

First documented co-infection case of cat-scratch disease and melioidosis in Malaysia: A cause of undifferentiated prolonged febrile illness.

Cat-scratch disease is a zoonotic infection of worldwide prevalence that is endemic in tropical or subtropical countries. Likewise, melioidosis is one of the major endemic health problems in Malaysia. Epidemiologically, mixed infections of cat-scratch disease and melioidosis are possible because similar environmental conditions are needed for the transmission of both infections. Still, their coinfection is rarely reported in medical literature. History of contact with plantation soil or contaminated water is important in raising the suspicion of the disease. Catscratch disease has increased as many children are in close proximity to cats. Here, we report a case of cat-scratch disease and melioidosis co-infection in a two-year-old boy who presented with prolonged fever and painless cervical lymphadenitis and had serological testing results positive for Bartonella henselae and Burkholderia pseudomallei. A history of travelling around Malaysia during school holidays and being exposed to cat and contaminated environment are clues to diagnosis.

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.

Laboratory Diagnosis of 37 Cases of Bartonella Endocarditis Based on Enzyme Immunoassay and Real-Time PCR.

Bartonella spp., mostly Bartonella quintana and B. henselae, are a common cause of culture-negative endocarditis. Serology using immunofluorescence assay (IFA) and PCR performed on cardiac tissues are the mainstays of diagnosis. We developed an enzyme immunoassay (EIA) and a novel multiplex real-time PCR assay, utilizing Bartonella genus-specific, B. henselae-specific, and B. quintana-specific SimpleProbe probes, for diagnosis of Bartonella endocarditis. We aimed to evaluate the performance of these assays. Thirty-seven patients with definite endocarditis, 18 with B. henselae, 18 with B. quintana, and 1 with B. koehlerae, were studied. Diagnosis was confirmed by conventional PCR and DNA sequencing of surgical cardiac specimens. Similar to the case with IFA, anti-Bartonella IgG titers of ≥1:800 were found in 94% of patients by EIA; cross-reactivity between B. henselae and B. quintana precluded species-specific serodiagnosis, and frequent (41%) but low-titer cross-reactivity between Coxiella burnetii antibodies and B. henselae antigen was found in patients with Q fever endocarditis. Low-titer (1:100) cross-reactivity was uncommonly found also in patients with brucellosis and culture-positive endocarditis, particularly Enterococcus faecalis endocarditis. Real-time PCR performed on explanted heart valves/vegetations was in complete agreement with results of sequence-based diagnosis with characteristic melting curves. The genus-specific probe identified five additional endocarditis-associated Bartonella spp. at the genus level. In conclusion, EIA coupled with a novel real-time PCR assay can play an important role in Bartonella endocarditis diagnosis and expand the diagnostic arsenal at the disposal of the clinical microbiologist. Since serology remains a major diagnostic tool, recognizing its pitfalls is essential to avoid incorrect diagnosis.

Bartonella infections diagnosed in the French reference center, 2014-2019, and focus on infections in the immunocompromised.

We studied retrospectively 651 PCR-confirmed Bartonella infections diagnosed at the French reference center for bartonellosis from 2014 to 2019. The most common form was cat-scratch disease (89%) followed by endocarditis (9%). Disseminated forms (2%) mainly presented as bacillary angiomatosis or peliosis hepatis in solid organ transplant recipients.

Molecular and Serological Survey of the Cat-Scratch Disease Agent (Bartonella henselae) in Free-Ranging Leopardus geoffroyi and Leopardus wiedii (Carnivora: Felidae) From Pampa Biome, Brazil.

The genus Bartonella comprises emerging bacteria that affect humans and other mammals worldwide. Felids represent an important reservoir for several Bartonella species. Domestic cats are the main reservoir of Bartonella henselae, the agent of cat scratch disease (CSD). It can be transmitted directly by scratches and bites from infected cats and via cat fleas. This study aims to investigate the circulation of Bartonella spp. in free-ranging Neotropical wild felids from Southern Brazil using serological and molecular methods. In this study, 53 live-trapped free-ranging wild felids were sampled, 39 Leopardus geoffroyi and 14 Leopardus wiedii, from five municipalities in the Rio Grande, do Sul state, southern Brazil. All captured animals were clinically healthy. Two blood samples of L. geoffroyi were positive, by PCR, for the presence of B. henselae DNA. Conversely, none of L. wiedii blood samples were positive when tested using PCR. Indirect immunofluorescence assay (IFA) showed that 28% of serum samples of wild felids were reactive (seropositive) for B. henselae by immunofluorescence, with titers ranging from 64 to 256. The results presented here provide the first evidence of a Bartonella-enzootic cycle involving L. geoffroyi and L. wiedii, which may account for the spillover of the emerging zoonotic pathogen B. henselae for the indigenous fauna in Southern Brazil.

Cerebral epidural empyema due to Bartonella henselae: a case report.

BACKGROUND: Cat scratch disease frequently involves a benign, self-limited disease. Neurological forms associated with Bartonella henselae are uncommon, consisting mostly in neuroretinitis, encephalitis and meningitis. Cerebral epidural empyema has never described. CASE PRESENTATION: An adult patient was hospitalized for isolated headaches. Magnetic Resonance Imaging (MRI) identified typical features of cerebral epidural empyema. The diagnosis of B. henselae was performed incidentally by 16S rDNA gene sequencing on the abscess fluid, and confirmed by specific qPCR. We report here the first case, to our knowledge, of cerebral epidural empyema associated with B. henselae. Further follow-up visits allowed identifying frequent cat scratches on the scalp as the presumptive source of infection. CONCLUSIONS: This case report alerts about such atypical clinical presentation, which requires an extensive clinical investigation. It also emphasizes on the usefulness of additional molecular diagnosis techniques in such CNS infection cases.

Early post-transplant cutaneous bacillary angiomatosis in a kidney recipient: Case report and review of the literature.

Bacillary angiomatosis (BA) is an uncommon systemic disease caused by Bartonella henselae (BH) or Bartonella quintana (BQ) that occurs primarily in immunocompromised hosts. Few cases of BA recipients have been reported in adult solid transplant recipients over the years, with most cases presenting years after transplant. We describe a case of a kidney transplant recipient who developed cutaneous BA very early in the post-transplant period despite not having any exposures. Retrospective testing of donor and recipient's serum was performed and raised the concern for possible donor-derived infection. A literature review encompassing 1990 to present was also performed in order to better understand the clinical presentation, diagnostics and therapeutic approach of this unusual disease. Combined serology, histopathology and molecular testing (polymerase chain reaction [PCR]) were useful in diagnosing BA in our patient as serology alone might be unreliable. Macrolides or doxycycline for at least 3 months is the recommended therapeutic strategy; however, the optimal duration of treatment is not well established in transplant recipients. In our patient, we decided to use doxycycline for 1 year due to gradual resolution of lesions and ongoing immunosuppression. Patient responded successfully without any documented relapse.

Bartonella henselae infection in the pediatric solid organ transplant recipient.

Bartonella henselae infection can cause a wide spectrum of diseases in both the immunocompetent and immunocompromised host with BA a severe form relegated to immunocompromised hosts, including solid organ transplant population. There are established criteria for diagnosis of Bartonella infection based on clinical presentation, serologic testing, imaging studies and, when indicated, tissue sampling for histopathological evaluation, particularly for BA. However, treatment recommendations for BA are inconclusive. Furthermore, there are no studies in the pediatric solid organ transplant population for antimicrobial therapy during BA secondary to Bartonella henselae infection. A case of BA following heart transplant is presented along with a literature review of clinical presentation; diagnosis and therapy for BA in the pediatric solid organ transplant population.