Amoebae as training grounds for microbial pathogens.

Grazing of amoebae on microorganisms represents one of the oldest predator-prey dynamic relationships in nature. It represents a genetic "melting pot" for an ancient and continuous multi-directional inter- and intra-kingdom horizontal gene transfer between amoebae and its preys, intracellular microbial residents, endosymbionts, and giant viruses, which has shaped the evolution, selection, and adaptation of microbes that evade degradation by predatory amoeba. Unicellular phagocytic amoebae are thought to be the ancient ancestors of macrophages with highly conserved eukaryotic processes. Selection and evolution of microbes within amoeba through their evolution to target highly conserved eukaryotic processes have facilitated the expansion of their host range to mammals, causing various infectious diseases. Legionella and environmental Chlamydia harbor an immense number of eukaryotic-like proteins that are involved in ubiquitin-related processes or are tandem repeats-containing proteins involved in protein-protein and protein-chromatin interactions. Some of these eukaryotic-like proteins exhibit novel domain architecture and novel enzymatic functions absent in mammalian cells, such as ubiquitin ligases, likely acquired from amoebae. Mammalian cells and amoebae may respond similarly to microbial factors that target highly conserved eukaryotic processes, but mammalian cells may undergo an accidental response to amoeba-adapted microbial factors. We discuss specific examples of microbes that have evolved to evade amoeba predation, including the bacterial pathogens- Legionella, Chlamydia, Coxiella, Rickettssia, Francisella, Mycobacteria, Salmonella, Bartonella, Rhodococcus, Pseudomonas, Vibrio, Helicobacter, Campylobacter, and Aliarcobacter. We also discuss the fungi Cryptococcus, and Asperigillus, as well as amoebae mimiviruses/giant viruses. We propose that amoeba-microbe interactions will continue to be a major "training ground" for the evolution, selection, adaptation, and emergence of microbial pathogens equipped with unique pathogenic tools to infect mammalian hosts. However, our progress will continue to be highly dependent on additional genomic, biochemical, and cellular data of unicellular eukaryotes.

Genome sequences of three Bartonella schoenbuchensis strains from Czechia.

Bartonella schoenbuchensis causes bacteremia in ruminants and is transmitted by deer keds. Here, we report the complete genome sequences of three B. schoenbuchensis strains (L2, L19, and L24) recently isolated from deer keds (Lipoptena fortisetosa) in Czechia.

Using clotted, pelleted blood samples for direct molecular detection of Bartonella spp. in small mammal wildlife surveillance studies.

OBJECTIVE: Bartonella are emerging bacterial zoonotic pathogens. Utilization of clotted blood samples for surveillance of these bacteria in wildlife has begun to supersede the use of tissues; however, the efficacy of these samples has not been fully investigated. Our objective was to compare the efficacy of spleen and blood samples for DNA extraction and direct detection of Bartonella spp. via qPCR. In addition, we present a protocol for improved DNA extraction from clotted, pelleted (i.e., centrifuged) blood samples obtained from wild small mammals. RESULTS: DNA concentrations from kit-extracted blood clot samples were low and A260/A280 absorbance ratios indicated high impurity. Kit-based DNA extraction of spleen samples was efficient and produced ample DNA concentrations of good quality. We developed an in-house extraction method for the blood clots which resulted in apposite DNA quality when compared to spleen samples extracted via MagMAX DNA Ultra 2.0 kit. We detected Bartonella in 9/30 (30.0%) kit-extracted spleen DNA samples and 11/30 (36.7%) in-house-extracted blood clot samples using PCR. Our results suggest that kit-based methods may be less suitable for DNA extraction from blood clots, and that blood clot samples may be superior to tissues for Bartonella detection.

Cat scratch disease unveils hidden breast carcinoma: A diagnostic twist.

Cat scratch disease is a rare condition that can present with different clinical manifestations, including axillary lymphadenopathy. Here, we report the case of a 45-year-old female who presented with axillary lymphadenopathy attributable to a process of differential diagnosis to cat scratch disease. During the thorough investigation of her condition, a routine mammogram was performed, due to the unilateral axillary lymphadenopathy, revealing the presence of previously undiagnosed breast carcinoma in situ; in fact, a DCIS (invasive ductal carcinoma with spread to the ipsilateral axillary nodes) was incidentally found. This case highlights the importance of comprehensive differential diagnosis and a multidisciplinary approach in managing patients with atypical presentations of common diseases, given that other alarming but unrelated findings are visible.

Fipronil and (S)-methoprene can lessen the risk of transmission of Bartonella clarridgeiae among cats with exposure to Ctenocephalides felis.

OBJECTIVE: To cohouse cats experimentally infected with Bartonella clarridgeiae (Bc) with naive cats in a flea-free environment or with Ctenocephalides felis, Bartonella henselae (Bh), Mycoplasma haemofelis, and Candidatus Mycoplasma haemominutum to determine which flea could be a vector and to assess whether transmission of the infectious agents could be blocked by fipronil and (S)-methoprene. ANIMALS: Specific pathogen-free cats (n = 34). METHODS: In experiment 1, Bc was inoculated in 1 cat that was housed with 9 naive cats without C felis. In experiment 2, the 2 cats inoculated with Bc were housed with 6 other cats (2 inoculated with Bh, 2 inoculated with M haemofelis, and 2 inoculated with Candidatus M haemominutum) in the center (enclosure 2) of 3 housing enclosures separated by mesh walls that allow passage of fleas but precludes fighting. C felis were placed only on cats in enclosure 2 (5 times). Cats in enclosures 1 (n = 8) and 2 (8) were untreated, and cats in enclosure 3 (8) were administered fipronil and (S)-methoprene. Blood was collected from all cats for PCR assays for the pathogens. RESULTS: None of the cats housed with the cat inoculated with Bc became PCR positive in the absence of C felis. All cats in enclosure 2 became Bc DNA positive. While 2 of 8 cats in enclosure 1 became Bc PCR positive, none of the treated cats in enclosure 3 became infected. CLINICAL RELEVANCE: The study demonstrated that C felis can be a vector for Bc. The results support the recommendation that flea control products can reduce the risk of transmission of flea-borne pathogens.

Bartonella, Blechomonas and Trypanosoma in fleas from the long-tailed ground squirrel (Spermophilus undulatus) in northwestern China.

Fleas are known to be vectors for a variety of pathogens in veterinary medicine. However, no information is available on the presence of Bartonella and Trypanosomatidae in fleas of the long-tailed ground squirrel (LTGR, Spermophilus undulatus). The present study shows detection of these pathogens in LTGR fleas. During 2022-2023, a total of 396 fleas were collected from 91 LTGRs in 4 alpine regions of Xinjiang Uygur Autonomous Region (northwestern China) and grouped into 54 flea pools. Flea species were identified according to morphological characteristics and molecular data. In addition, all flea samples were analyzed for Bartonella with amplification and sequencing of a 380-bp part of the gltA gene and Trypanosomatidae with targeting the 18S rRNA (850-bp) and gGAPDH (820-bp) genes. The flea species included Frontopsylla elatoides elatoides (203), Neopsylla mana (49), and Citellophilus tesquorum dzetysuensis (144). Of 54 flea pools, seven (12.96%) tested positive for Bartonella, and three (5.56%) were positive for Trypanosomatidae. Based on BLASTn and phylogenetic analyses, i) Bartonella washoensis in F. elatoides elatoides and C. tesquorum dzetysuensis, and Bartonella rochalimae in F. elatoides elatoides were identified. Interestingly, a new haplotype within the species Ba. washoensis was discovered in C. tesquorum dzetysuensis; and ii) Blechomonas luni was confirmed in C. tesquorum dzetysuensis and Trypanosoma otospermophili in F. elatoides elatoides. Two Bartonella species and two Trypanosomatidae members were discovered for the first time in fleas from LTGRs. This study broadens our understanding of the geographic distribution and potential vectors for Bartonella and Trypanosomatidae.

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.

Human Babesia odocoilei and Bartonella spp. co-infections in the Americas.

BACKGROUND: In recent years, Babesia and Bartonella species co-infections in patients with chronic, nonspecific illnesses have continued to challenge and change the collective medical understanding of "individual pathogen" vector-borne infectious disease dynamics, pathogenesis and epidemiology. The objective of this case series is to provide additional molecular documentation of Babesia odocoilei infection in humans in the Americas and to emphasize the potential for co-infection with a Bartonella species. METHODS: The development of improved and more sensitive molecular diagnostic techniques, as confirmatory methods to assess active infection, has provided increasing clarity to the healthcare community. RESULTS: Using a combination of different molecular diagnostic approaches, infection with Babesia odocoilei was confirmed in seven people suffering chronic non-specific symptoms, of whom six were co-infected with one or more Bartonella species. CONCLUSIONS: We conclude that infection with Babesia odocoilei is more frequent than previously documented and can occur in association with co-infection with Bartonella spp.

Metabarcoding using nanopore sequencing enables identification of diverse and zoonotic vector-borne pathogens from neglected regions: A case study investigating dogs from Bhutan.

The diversity and prevalence of canine vector-borne pathogens (VBPs) in Bhutan have to date remained unexplored, whilst recent epidemiological surveys in other South Asian nations have found diseases caused by VBPs to be rife in local dog populations. Importantly, many of such VBPs can infect people as well, with a building body of evidence identifying potentially zoonotic rickettsial organisms infecting humans in Bhutan. Given the lack of data on canine pathogens in Bhutan we employed a suite of deep-sequencing metabarcoding methods using Oxford Nanopore Technologies' MinION™ device to holistically characterise the bacterial, apicomplexan and filarial worm blood-borne pathogens of dogs in the country's south. Of the 95 stray, owned and community dogs sampled 78% (95% CI = 69%-85%) were infected with at least one VBP. Pathogen species detected were highly diverse including the bacteria Mycoplasma haemocanis in 16% (95% CI: 10-24%), Ehrlichia canis in 4% (95% CI: 2-10%), Anaplasma platys in 2% (95% CI: 0.5-7%) of dogs as well as the zoonotic species Bartonella clarridgeiae in 1% (95% CI: 0.1-6%), a potentially novel Bartonella spp. and an Ehrlichia chaffeensis-like bacterium, both in 1% (95% CI: 0.1-6%) of dogs. The apicomplexan haemoparasites Hepatozoon canis in 62% (95% CI: 52-71%), Babesia gibsoni in 45% (95% CI: 36-55%) and Babesia vogeli in 3% (95% CI: 1-9%) of dogs were also detected. Finally, 5% (95% CI: 2-12%) of dogs were found to be infected with the filarioid Acanthocheilonema reconditum and 1% (95% CI: 0.1-6%) with zoonotic Dirofilaria sp. hongkongensis. One canine was found positive to the filarioid Setaria tundra, a species normally found infecting cervids. The elucidated diversity of VBP communities highlights the strength of assumption-free diagnostics, such as metabarcoding, in detecting rare, novel, and unexpected pathogens. This approach to identifying pathogen diversity is of critical importance when investigating regions and populations that have thus far been neglected, with the findings aiding the development of future One Health informed strategies for disease control.

Prevalence and genetic diversity of Bartonella spp. in wild small mammals from South Africa.

Bartonella spp. are intracellular bacteria associated with several re-emerging human diseases. Small mammals play a significant role in the maintenance and spread of Bartonella spp. Despite the high small mammal biodiversity in South Africa, there is limited epidemiological information regarding Bartonella spp. in these mammals. The main aim of this study was to determine the prevalence and genetic diversity of Bartonella spp. from wild small mammals from 15 localities in 8 provinces of South Africa. Small mammals (n = 183) were trapped in the Eastern Cape, Free State, Gauteng, Limpopo, Mpumalanga, Northern Cape, North West, and Western Cape provinces of South Africa between 2010 and 2018. Heart, kidney, liver, lung, and spleen were harvested for Bartonella DNA screening, and prevalence was determined based on the PCR amplification of partial fragments of the 16S-23S rRNA intergenic spacer (ITS) region, gltA, and rpoB genes. Bartonella DNA was detected in Aethomys chrysophilus, Aethomys ineptus, Gerbillurus spp., Lemniscomys rosalia, Mastomys coucha, Micaelamys namaquensis, Rhabdomys pumilio, and Thallomys paedulcus. An overall prevalence of 16.9% (31/183, 95% CI: 12.2%-23%) was observed. Bartonella elizabethae, Bartonella grahamii, and Bartonella tribocorum were the zoonotic species identified, while the remaining sequences were aligned to uncultured Bartonella spp. with unknown zoonotic potential. Phylogenetic analyses confirmed five distinct Bartonella lineages (I-V), with lineage IV displaying strong M. coucha host specificity. Our results confirm that South African wild small mammals are natural reservoirs of a diverse assemblage of Bartonella spp., including some zoonotic species with high genetic diversity, although prevalence was relatively low.IMPORTANCESmall mammals play a significant role in the maintenance and spread of zoonotic pathogens such as Bartonella spp. Despite the high small mammal biodiversity in southern Africa including South Africa, there is limited epidemiological information regarding Bartonella spp. in these mammals across the country. Results from our study showed the liver and spleen had the highest positive cases for Bartonella spp. DNA among the tested organs. Bartonella elizabethae, B. grahamii, and B. tribocorum were the three zoonotic species identified and five distinct Bartonella lineages (I-V) were confirmed through phylogenetic analyses. To the best of our knowledge, this study presents the first extensive nuclear diversity investigation of Bartonella spp. in South African small mammals in South Africa.

Paws and Pathogens: A Multidisciplinary Approach Through Bartonella henselae Endocarditis and Hepatosplenic T-Cell Lymphoma.

Bartonella species are gram-negative coccobacilli that are globally recognized as significant pathogens causing zoonotic infections. Among Bartonella species, B. henselae, B. quintana, and B. bacilliformis are prominent pathogens causing infections in humans, often manifesting as infective endocarditis. Bartonella endocarditis can pose diagnostic challenges due to its indolent presentation and limitations of standard microbiological culture techniques to identify the organism. We report a case of a 23-year-old male, who initially presented with the manifestations of hepatosplenic T-cell lymphoma, later diagnosed with blood culture-negative endocarditis caused by B. henselae. The patient had a complicated clinical course including pancytopenia, hepatosplenomegaly, and severe aortic valve regurgitation. Despite negative blood cultures, diagnostic clues included persistent fevers and bicuspid aortic valve with abscess. High Bartonella IgG titers (>1:800) supported the diagnosis. This case underscores the importance of considering Bartonella species in patients with suspected endocarditis, particularly in those with predisposing factors and negative blood cultures. Diagnosis relies heavily on serologic assays due to low sensitivity of conventional culture methods. Treatment involves a multidisciplinary approach with antibiotics and surgical intervention for optimal outcomes. Timely recognition and management are crucial to mitigate the high mortality associated with Bartonella endocarditis, and we hope this article offers insight for clinicians.

Metagenomic Detection of Bacterial Zoonotic Pathogens among Febrile Patients, Tanzania, 2007-20091.

Bacterial zoonoses are established causes of severe febrile illness in East Africa. Within a fever etiology study, we applied a high-throughput 16S rRNA metagenomic assay validated for detecting bacterial zoonotic pathogens. We enrolled febrile patients admitted to 2 referral hospitals in Moshi, Tanzania, during September 2007-April 2009. Among 788 participants, median age was 20 (interquartile range 2-38) years. We performed PCR amplification of V1-V2 variable region 16S rRNA on cell pellet DNA, then metagenomic deep-sequencing and pathogenic taxonomic identification. We detected bacterial zoonotic pathogens in 10 (1.3%) samples: 3 with Rickettsia typhi, 1 R. conorii, 2 Bartonella quintana, 2 pathogenic Leptospira spp., and 1 Coxiella burnetii. One other sample had reads matching a Neoerhlichia spp. previously identified in a patient from South Africa. Our findings indicate that targeted 16S metagenomics can identify bacterial zoonotic pathogens causing severe febrile illness in humans, including potential novel agents.

Molecular Survey on the Occurrence of Tick-Borne Bacteria in Wild Birds from Central Italy.

Birds are known to be carriers of ticks infected by tick-borne pathogens, including bacteria. However, not many studies have been carried out on avian tissues to detect these agents. The aim of the present survey was to investigate, using PCR, the presence of Anaplasma phagocytophilum, Bartonella spp., Borrelia burgdorferi sensu lato, Chlamydia psittaci, Coxiella burnetii, Ehrlichia canis, Francisella tularensis, and Rickettsia spp. in the spleens collected from 300 wild birds of different orders and species from Central Italy. A total of 53 (17.67%) samples were PCR positive for at least one investigated pathogen. One (0.33%) bird was positive for Bartonella spp., five (1.67%) birds were positive for C. burnetii, eleven (3.67%) for B. burgdorferi s.l., and thirty-six (12%) for C. psittaci. No coinfection was detected. All samples were negative for A. phagocytophilum, E. canis, F. tularensis, and Rickettsia spp. The findings showed that wild birds may harbor different zoonotic tick-borne bacteria; therefore, they can contribute to the diffusion of these agents.

Seroprevalence of zoonotic pathogens in stray cats in an urban area of northeast Spain.

The feline population is extensive in urban areas worldwide, comprising stray and domestic cats. Cats, acting as reservoirs, can transmit various zoonotic organisms to humans, which can cause significant public health issues. We evaluated the seroprevalence of zoonotic pathogens in stray cats in an urban area of northeast Spain (the city of Zaragoza) to assess potential risks to human health. A total of 88 sampled cats (52 females and 36 males) underwent antibody evaluation using the indirect immunofluorescence technique. Seroprevalence rates were determined for IgG antibodies to Bartonella henselae (36.3%), Toxoplasma gondii (31.8%), Rickettsia felis (14.7%), Rickettsia typhi (9%), and Leishmania infantum (10.2%). Our results confirmed the presence in stray cats of antibodies against all those pathogens, indicating that they all circulate in the feline population in Zaragoza. Male cats exhibited a higher predisposition to T. gondii, whereas females showed an increased likelihood of contracting B. henselae. This difference may be attributed to distinct behaviors according to sex. Our findings underscore the importance of maintaining and intensifying surveillance coupled with preventive measures against zoonotic pathogens in cats. They highlight the need for comprehensive control strategies designed to mitigate public health risks associated with feline populations.

Potential drivers of vector-borne pathogens in urban environments: European hedgehogs (Erinaceus europaeus) in the spotlight.

Vector-borne diseases (VBDs) are considered as (re-)emerging, but information on the transmission cycles and wildlife reservoirs is often incomplete, particularly with regard to urban areas. The present study investigated blood samples from European hedgehogs (Erinaceus europaeus) presented at wildlife rehabilitation centres in the region of Hanover. Past exposure to B. burgdorferi sensu lato (s.l.) and tick-borne encephalitis virus (TBEV) was assessed by serological detection of antibodies, while current infections with Borrelia spp., Anaplasma phagocytophilum, Rickettsia spp., Neoehrlichia mikurensis, Bartonella spp., Babesia spp. and Spiroplasma ixodetis were investigated by (q)PCR. Of 539 hedgehogs tested for anti-Borrelia antibodies, 84.8% (457/539) were seropositive, with a higher seropositivity rate in adult than subadult animals, while anti-TBEV antibodies were detected in one animal only (0.2%; 1/526). By qPCR, 31.2% (168/539) of hedgehog blood samples were positive for Borrelia spp., 49.7% (261/525) for A. phagocytophilum, 13.0% (68/525) for Bartonella spp., 8.2% for S. ixodetis (43/525), 8.0% (42/525) for Rickettsia spp. and 1.3% (7/525) for Babesia spp., while N. mikurensis was not detected. While further differentiation of Borrelia spp. infections was not successful, 63.2% of the A. phagocytophilum infections were assigned to the zoonotic ecotype I and among Rickettsia spp. infections, 50.0% to R. helvetica by ecotype- or species-specific qPCR, respectively. Sequencing revealed the presence of a Rickettsia sp. closely related to Rickettsia felis in addition to a Bartonella sp. previously described from hedgehogs, as well as Babesia microti and Babesia venatorum. These findings show that hedgehogs from rehabilitation centres are valuable sources to identify One Health pathogens in urban areas. The hedgehogs are not only exposed to pathogens from fleas and ticks in urban areas, but they also act as potent amplifiers for these vectors and their pathogens, relevant for citizens and their pets.

Canine Bacterial Endocarditis: A Text Mining and Topics Modeling Analysis as an Approach for a Systematic Review.

Bacterial endocarditis (BE) is a severe infection of the endocardium and cardiac valves caused by bacterial agents in dogs. Diagnosis of endocarditis is challenging due to the variety of clinical presentations and lack of definitive diagnostic tests in its early stages. This study aims to provide a research literature analysis on BE in dogs based on text mining (TM) and topic analysis (TA) identifying dominant topics, summarizing their temporal trend, and highlighting any possible research gaps. A literature search was performed utilizing the Scopus® database, employing keywords pertaining to BE to analyze papers published in English from 1990 to 2023. The investigation followed a systematic approach based on the PRISMA guidelines. A total of 86 records were selected for analysis following screening procedures and underwent descriptive statistics, TM, and TA. The findings revealed that the number of records published per year has increased in 2007 and 2021. TM identified the words with the highest term frequency-inverse document frequency (TF-IDF), and TA highlighted the main research areas, in the following order: causative agents, clinical findings and predisposing factors, case reports on endocarditis, outcomes and biomarkers, and infective endocarditis and bacterial isolation. The study confirms the increasing interest in BE but shows where further studies are needed.

Epidemiological survey and genetic diversity of Bartonella in fleas collected from rodents in Fujian Province, Southeast China.

BACKGROUND: Fleas, considered to be the main transmission vectors of Bartonella, are highly prevalent and show great diversity. To date, no investigations have focused on Bartonella vectors in Southeast China. The aim of this study was to investigate the epidemiological and molecular characteristics of Bartonella in fleas in Southeast China. METHODS: From 2016 to 2022, flea samples (n = 1119) were collected from 863 rodent individuals in seven inland and coastal cities in Southeast China. Flea species, region, gender, host species and habitat were recorded. The DNA samples from each individual flea were screened by real-time PCR for the Bartonella ssrA gene. All positive samples were confirmed by PCR based on the presence of the gltA gene and sequenced. The factors associated with Bartonella infection were analyzed by the Chi-square test and Fisher's exact test. ANOVA and the t-test were used to compare Bartonella DNA load. RESULTS: Bartonella DNA was detected in 26.2% (293/1119) of the flea samples, including in 27.1% (284/1047) of Xenopsylla cheopis samples, 13.2% (5/38) of Monopsyllus anisus samples, 8.3% (2/24) of Leptopsylla segnis samples and 20.0% (2/10) of other fleas (Nosopsyllus nicanus, Ctenocephalides felis, Stivalius klossi bispiniformis and Neopsylla dispar fukienensis). There was a significant difference in the prevalence of Bartonella among flea species, sex, hosts, regions and habitats. Five species of Bartonella fleas were identified based on sequencing and phylogenetic analyses targeting the gltA gene: B. tribocorum, B. queenslandensis, B. elizabethae, B. rochalimae and B. coopersplainsensis. CONCLUSIONS: There is a high prevalence and diversity of Bartonella infection in the seven species of fleas collected in Southeast China. The detection of zoonotic Bartonella species in this study, including B. tribocorum, B. elizabethae and B. rochalimae, raises public health concerns.

[Cat-scratch disease, clinical features in adults]. / Características clínicas de pacientes adultos con enfermedad por arañazo de gato.

INTRODUCTION: Cat-scratch disease (CSD) is caused by Bartonella henselae and it is under-recognized in adults because it mainly affects children. Clinical course is commonly benign and self-limited; occasionally, there may be systemic involvement. METHODS: Case-series study carried out in a tertiary care hospital in Buenos Aires suburbs. Patients older than 15 years diagnosed with CSD over a 5-year period were included (2016-2021). RESULTS: 30 adult patients were analyzed, with a median age of 20.5 years (IQR 17-29), 73% (n = 22) were male; 96% (n = 27) had history of exposure to cats. The most common clinical presentation of CSD was peripheral lymphadenopathy (90%), the average complication rate was 33% (n = 10), 86.7% (n = 26) received antimicrobial therapy, with a median duration of 5 days (IQR 5-10). Outcome was favorable in 83% (n = 25), 16% (n = 5) were lost to follow-up. DISCUSSION: Clinical features of CSD in adults are poorly described in the worldwide literature. Diagnosis can be challenging because the clinical hallmark is regional lymphadenopathy.

Introducción: La enfermedad por arañazo de gato (EAG) es producida por Bartonella henselae y debido a que afecta principalmente niños, es poco reconocida en adultos. El cuadro evolutivo es generalmente benigno y autolimitado, aunque ocasionalmente puede haber compromiso sistémico. Métodos: Estudio observacional, descriptivo y retrospectivo realizado en un hospital de tercer nivel del conurbano bonaerense. Se incluyeron pacientes mayores de 15 años con diagnóstico de EAG en un período de 5 años (2016-2021). Resultados: Se analizaron 30 pacientes adultos, con una mediana de edad de 20.5 años (17-29), el 73% (n = 22) fueron varones. El 96% (n = 27) presentó contacto estrecho con gatos. La presentación clínica más frecuente fue adenopatías periféricas (90%); el porcentaje de complicaciones fue de 33% (n = 10). La indicación de antibioticoterapia fue de 86.7% (n = 26), con una mediana de duración de 5 días (5-10). La evolución fue favorable en el 83% (n = 25), en el 16% (n = 5) se perdió seguimiento. Discusión: La EAG es poco reconocida en adultos; las características clínicas de este grupo etario se encuentran poco descriptas en la literatura. Es un desafío diagnóstico debido a que su forma de presentación más frecuente es la adenopatía localizada.

Bartonella species bacteremia in association with adult psychosis.

Introduction: The potential role of pathogens, particularly vector-transmitted infectious agents, as a cause of psychosis has not been intensively investigated. We have reported a potential link between Bartonella spp. bacteremia and neuropsychiatric symptoms, including pediatric acute onset neuropsychiatric syndrome and schizophrenia. The purpose of this study was to further assess whether Bartonella spp. exposure or infection are associated with psychosis. Methods: In a blinded manner, we assessed the presence of anti-Bartonella antibodies by indirect immunofluorescence assays (IFA), and infection by amplification of bacterial DNA from blood by quantitative polymerase chain reaction (qPCR), digital PCR (dPCR), and droplet digital PCR (ddPCR) in 116 participants. Participants were categorized into one of five groups: 1) controls unaffected by psychosis (n = 29); 2) prodromal participants (n = 16); 3) children or adolescents with psychosis (n = 7); 4) adults with psychosis (n = 44); and 5) relatives of a participant with psychosis (n = 20). Results: There was no significant difference in Bartonella spp. IFA seroreactivity between adults with psychosis and adult controls unaffected by psychosis. There was a higher proportion of adults with psychosis who had Bartonella spp. DNA in the bloodstream (43.2%) compared to adult controls unaffected by psychosis (14.3%, p = 0.021). The Bartonella species was determined for 18 of the 31 bacteremic participants, including infection or co-infection with Bartonella henselae (11/18), Bartonella vinsonii subsp. berkhoffii (6/18), Bartonella quintana (2/18), Bartonella alsatica (1/18), and Bartonella rochalimae (1/18). Discussion: In conjunction with other recent research, the results of this study provide justification for a large national or international multi-center study to determine if Bartonella spp. bacteremia is more prevalent in adults with psychosis compared to adults unaffected by psychosis. Expanding the investigation to include a range of vector-borne and other microbial infections with potential CNS effects would enhance knowledge on the relationship between psychosis and infection.

Vague Presentation of Cat Scratch Disease in a Child.

Background: Prolonged fever for more than a week or fever of unknown origin in pediatric patients with or without soft tissue infection should raise suspicion for Bartonella henselae infection. Case Report: A 10-year-old female presented to urgent care with a "bug bite" on the left ring finger, cough, and 2 to 3 days of low-grade fever. Ten days later, her symptoms progressed to soft tissue swelling of the left elbow without fracture on radiograph. Magnetic resonance imaging revealed multiple reniform masses with avid contrast enhancement consistent with suppurative adenitis. She was admitted for irrigation and debridement. The patient underwent surgical debridement with removal of infected lymph nodes. Histology revealed necrotizing granulomatous lymphadenitis. Polymerase chain reaction was positive for B henselae. Antibody titer revealed B henselae immunoglobulin G titer of 1:512 (reference, 1:64), and negative immunoglobulin M titers were indicative of mature immune response. The patient was treated with azithromycin 250 mg tablets twice daily for 3 days followed by 3 days of the 250 mg tablet once daily. Follow-up showed resolution of infection without symptoms concerning for visceral organ infection. Conclusion: While the patient's initial presentation was vague, a complete history, quick follow-up, and decisive intervention prevented significant sequelae such as visceral organ involvement.