Bartonella henselae IgM seropositivity in both adult and pediatric patients with diverse clinical conditions in Turkey

A Retrospective Analysis of Systemic Bartonella henselae Infection in Children

Systemic Bartonella henselae infection, also known as cat-scratch disease (CSD), presents a diagnostic challenge due to the variability of clinical manifestations and the potential for serological cross-reactivity with other organisms. This study aimed to retrospectively analyze the epidemiological, clinical, laboratory, and imaging characteristics of pediatric patients diagnosed with systemic B. henselae infection, to improve understanding and facilitate timely diagnosis and treatment. We conducted a 10-year retrospective study at the "Louis Turcanu" Children's Emergency Hospital and private clinics in Timisoara, Romania, reviewing records for confirmed cases of B. henselae infection from January 2014 to January 2024. The study adhered to the Declaration of Helsinki and received approval from the Institutional Review Board. Diagnostic criteria included contact with animals, prolonged fever, hematological and/or hepatosplenic manifestations, and positive serological tests for B. henselae. Nineteen pediatric patients were identified with a median age of 8.1 years. The majority were exposed to felines (94.7%), reflecting the disease's epidemiological profile. Clinical findings highlighted fever (47.4%), lymphadenopathy (78.9%), and less frequently, abdominal pain and headache (both 10.5%). Laboratory analyses revealed a mean hemoglobin of 12.6 mg/dL, WBC count of 13.1 × 103 cells/microliter, and platelet count of 340.6 × 103 per microliter. Significant findings included elevation in ESR and CRP in 47.4% and 21.1% of patients, respectively, and high seropositivity rates for B. henselae IgM (63.2%) and IgG (94.7%). Imaging studies demonstrated widespread lymphadenopathy and occasional splenomegaly and hepatic microabscesses. All patients received antibiotic therapy, with azithromycin being the most commonly used (94.7%). Co-infections with Epstein-Barr Virus, Cytomegalovirus, and Toxoplasma gondii were documented, indicating the complex infectious status of the patients. Systemic B. henselae infection in children predominantly manifests with fever and lymphadenopathy, with a significant history of exposure to felines. Laboratory and imaging findings support the diagnosis, which is further complicated by potential co-infections. Effective antibiotic therapy, primarily with azithromycin, underscores the need for comprehensive diagnostic and treatment strategies. This study emphasizes the importance of considering systemic B. henselae infection in pediatric patients with prolonged fever and contact with cats, to ensure timely and appropriate treatment.

Molecular detection and identification of Bartonella species in cats from Hamedan and Kermanshah, Western Iran

Bartonella species are emerging vector-borne zoonotic pathogens which infect a wide range of domestic and wild animals as well as humans. Cats are the primary reservoir hosts for several zoonotic Bartonella spp., the most common being B. henselae the causative agent of cat scratch disease. Despite the important role of cats in the epidemiology of bartonellosis, there is limited information about the prevalence and species infecting cats in Iran. The aim of present study was molecular detection and identification of Bartonella species in cats from two western provinces Hamedan and Kermanshah. From December 2018 to February 2021, 87 cats (n = 26 from Hamedan, n = 61 from Kermanshah) were examined clinically, their bodies were searched for collection of ectoparasites, and cephalic or saphenous blood specimens were collected. Genomic DNA was extracted from blood specimens and conventional PCRs targeting the rpoB, and ITS regions of Bartonella spp. were performed. Positive samples were sequenced and analysed phylogenetically. Bartonella DNA was detected in 11/87 cats (12.64 %). Sequencing results revealed the presence of B. henselae in cats from Hamedan, and B. clarridgeiae and B. henselae in cats from Kermanshah. A statistical association between cat origin and the prevalence of Bartonella spp. was observed in the studied population. This study confirms for the first time the circulation of Bartonella spp. in cats in two western Iranian provinces. Prevention strategies e.g. ectoparasites control, and regular examination of pet and urban cats are suggested for minimising Bartonella infection in cats and subsequently in humans.

Molecular prevalence and genetic diversity of Bartonella spp. in stray cats of İzmir, Turkey

Background

Bartonella spp. are vector-borne pathogens that cause zoonotic infections in humans. One of the most well-known of these is cat-scratch disease caused by Bartonella henselae and Bartonella clarridgeiae, with cats being the major reservoir for these two bacteria. Izmir, Turkey is home to many stray cats, but their potential role as a reservoir for the transmission of Bartonella to humans has not been investigated yet. Therefore, the aim of this study was to investigate the prevalence of Bartonella species and their genetic diversity in stray cats living in Izmir.

Methods

Molecular prevalence of Bartonella spp. in stray cats (n = 1012) was investigated using a PCR method targeting the 16S-23S internal transcribed spacer gene (ITS), species identification was performed by sequencing and genetic diversity was evaluated by haplotype analysis.

Results

Analysis of the DNA extracted from 1012 blood samples collected from stray cats revealed that 122 samples were Bartonella-positive, which is a molecular prevalence of 12.05% (122/1012; 95% confidence interval [CI] 10.1–14.2%). Among the Bartonella-positive specimens, 100 (100/122; 81.96%) were successfully sequenced, and B. henselae (45/100; 45%), B. clarridgeiae (29/100; 29%) and Bartonella koehlerae (26/100; 26%) were identified by BLAST and phylogenetic analyses. High genetic diversity was detected in B. clarridgeiae with 19 haplotypes, followed by B. henselae (14 haplotypes) and B. koehlerae (8 haplotypes).

Conclusions

This comprehensive study analyzing a large number of samples collected from stray cats showed that Bartonella species are an important source of infection to humans living in Izmir. In addition, high genetic diversity was detected within each Bartonella species.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05431-3.

A Case of Atypical Bartonellosis in a 4-Year-Old Immunocompetent Child

In most cases, infection due to Bartonella henselae causes a mild disease presenting with a regional lymphadenopathy frequently associated with a low-grade fever, headache, poor appetite and exhaustion that spontaneously resolves itself in a few weeks. As the infection is generally transmitted by cats through scratching or biting, the disease is named cat scratch disease (CSD). However, in 5–20% of cases, mainly in immunocompromised patients, systemic involvement can occur and CSD may result in major illness. This report describes a case of systemic CSD diagnosed in an immunocompetent 4-year-old child that can be used as an example of the problems that pediatricians must solve to reach a diagnosis of atypical CSD. Despite the child’s lack of history suggesting any contact with cats and the absence of regional lymphadenopathy, the presence of a high fever, deterioration of their general condition, increased inflammatory biomarkers, hepatosplenic lesions (i.e., multiple abscesses), pericardial effusion with mild mitral valve regurgitation and a mild dilatation of the proximal and medial portion of the right coronary artery, seroconversion for B. henselae (IgG 1:256) supported the diagnosis of atypical CSD. Administration of oral azithromycin was initiated (10 mg/kg/die for 3 days) with a progressive normalization of clinical, laboratory and US hepatosplenic and cardiac findings. This case shows that the diagnosis of atypical CSD is challenging. The nonspecific, composite and variable clinical features of this disease require a careful evaluation in order to achieve a precise diagnosis and to avoid both a delayed diagnosis and therapy with a risk of negative evolution.