Bartonella endocarditis

Bartonella henselae Hepatic Abscesses and Associated Osteomyelitis in a Pediatric Patient

Bartonella henselae is a Gram-negative bacillus transmitted to humans via cat saliva or scratch. Cat scratch disease, the typical clinical manifestation of B. henselae infection, presents as localized cutaneous or regional lymphadenopathy. Rare, atypical presentations, generally reflecting bloodborne disseminated disease, can include hepatosplenic, cardiac, ocular, neurologic, or musculoskeletal involvement. Here, we present a case of disseminated B. henselae with hepatic abscesses and associated ischial osteomyelitis in an immunocompetent 2-year-old male patient. Although osteomyelitis is a rare manifestation of B. henselae infection, it should be included in the differential diagnosis in pediatric patients presenting with fever of unknown origin and musculoskeletal pain, especially in the setting of cat exposure. Hepatic involvement of B. henselae infection is associated with significant morbidity; therefore, abdominal imaging is critical in the diagnostic workup. This patient was successfully treated after a 6-week course of azithromycin and rifampin, as evidenced by symptom resolution and improved fluid collections on repeat imaging. While most cases of B. henselae resolve without treatment, in severe or disseminated infection such as this case, antibiotics such as azithromycin and rifampin should be considered for treatment.

Evaluation of the available animal models for Bartonella infections

The diseases caused by the Bartonella genus of bacteria are clinically diverse, and can be challenging to cure. The study of bartonellosis has been hampered by the lack of a suitable animal model. Preclinical studies for novel therapeutics and a competent host for vector transmission studies are needed to fill critical knowledge gaps. The studies included here are a representation of in vivo Bartonella research and the corresponding challenges. This review examines the current state of available animal models by assessing the success of various model species and strains in Bartonella infection. With a focus on the strengths and weaknesses of current animal models, the importance of these models for improvement of human health and veterinary care is emphasized.

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.

Development and validation of a droplet digital PCR assay for the detection and quantification of Bartonella species within human clinical samples

This report describes the development, optimization, and validation of a ddPCR assay for the detection of Bartonella spp. DNA within several sample matrices, including clinical blood samples from patients with or without documented Bartonella spp. bacteremia. The Bartonella spp. ddPCR assay was developed based upon previously published TaqMan-based qPCR assays that can amplify DNA of over 25 Bartonella spp. Host DNA (housekeeping gene) amplification serves as a reference target to facilitate quantification. The efficiency, sensitivity, and specificity of the Bartonella spp. ddPCR assay was assessed by direct comparison with the current qPCR methods used by the Intracellular Pathogens Research Laboratory (North Carolina State University, North Carolina, USA), and Galaxy Diagnostics (Research Triangle Park, North Carolina, USA). Bartonella spp. ddPCR assay parameters were successfully optimized to detect Bartonella concentrations equivalent to 0.5 bacterial genome copies per microliter of blood (0.001 pg/ul of bacterial DNA). The number of droplets detected (resolution) for each concentration was consistent across each of four assessed time points. The Bartonella spp. ddPCR assay detected 16 species/strains including B. henselae; B. quintana; B. vinsonii subsp. berkhoffii (genotypes I, II, III and IV); B. vinsonii subsp. vinsonii; B. melophagi; B. volans; B. monaki; B. alsatica; B. bovis; B. elizabethae; B. clarridgeiae; and B. koehlerae. Bartonella DNA was detected in only one previously negative patient sample (119/120 negative; 99% specificity). The ddPCR sensitivity (53/112) was significantly better than qPCR (6/112) when testing patient blood and enrichment blood culture samples. The development of commercial ddPCR systems with integrated technologies has significantly streamlined the DNA detection process, making it more efficient and standardized for clinical diagnostic testing. The assay described in this work is the first step toward the development of a multiplex ddPCR assay (i.e., using the QX One from Bio-Rad) for the simultaneous detection and absolute quantification of multiple vector-borne pathogens (such as Babesia, Bartonella and Borrelia) within clinical samples.