Evaluation of Bartonella henselae by molecular and serological assays in different clinical specimens from patients with suspected cat scratch disease

Background: Bartonella henselae is the etiological agent of cat scratch disease (CSD), a common infection that usually occurs in children presenting as a self-limiting lymphadenopathy. In a minority of cases, including immunocompromised individuals, B. henselae can cause atypical infections. Given the slow and difficult growth in culture, diagnosis is usually made by epidemiological, clinical, histological and serological criteria. In this study, a qualitative real-time PCR has been used in order to evaluate its suitability for diagnosing B. henselae in comparison to serology. Material/methods: Between march 2011 and may 2016, 139 clinical specimens (lymphonodal biopsies, blood, exudates) from 129 patients (M/F 52/77; 10 adults/119 children, age 3 months-68 years) with suspected CSD were evaluated at the Microbiology and Virology Unit, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, by serological (IgM and IgG) and molecular assays. Clinical charts were reviewed in all patients. Results: Overall, 86/129 patients (66.7%) were PCR-negative (non-CSD group; M/F 33/53, age 3 months-37 years) and 43 (33.3%) PCR-positive (CSD group; M/F 19/24, age 7 months-68 years, including 5 adults and 38 children). Serology was available for 28 CSD patients: 8 (28.57%) IgMpositive, two of which also IgG-positive; 20 IgM+IgG-negative. CSD was diagnosed in all patients from CSD group, whereas other infective causes were evidenced in the remaining patients. Conclusions: Real-time-PCR allows for a timely CSD diagnosis, especially in subjects in which serology does not evidence the occurrence of an antibody response. A rapid and accurate diagnosis of CSD may prevent unnecessary diagnostic procedures and allows for an appropriate clinical and therapeutic management, including antibiotic treatment.