Helicobacter canis bacteraemia in a rheumatoid arthritis patient treated with tofacitinib: case report and literature review

BACKGROUND: Non-Helicobacter pylori species (NHPS) are newly emerging bacteria that naturally inhabit birds and mammals apart from humans and rarely cause diseases in humans. In recent years, a rise in the number of cases associated with NHPS infections in humans has been observed. Among them, infections with Helicobacter (H.) canis are sporadic and challenging to recognise clinically. To date, ten cases of H. canis infections in mainly immunocompromised humans have been reported in the literature. Transmission pathway is most likely zoonotic via the faecal-oral route during close contacts with dogs and cats or may result from a contaminated sheep milk intake. No clear guidelines for successful antibiotic regimen are known. Important additional risk factor for infection might be biologic agents and Janus kinase inhibitors (JAKi) used in the treatment of rheumatoid arthritis (RA) and other conditions. Herein we present the first case of H. canis bacteraemia in a RA patient treated with novel JAKi tofacitinib. CASE PRESENTATION: A 65-year-old female patient with RA and rituximab-induced hypogammaglobulinemia treated with tofacitinib, methotrexate, and methylprednisolone came to a planned visit in our outpatient rheumatology clinic. She presented with a history of back pain that significantly worsened 2 days before visit. She had numbness and tingling sensation in both legs and muscle weakness. Neurological examination was within a normal range. The patient was afebrile, had no chills, and was haemodynamically stable. She was in close contact with her pet dogs. Laboratory examination showed increased markers of inflammation. She was found to have H. canis bacteraemia with underlying multilevel degenerative lumbar spinal stenosis. Identification of H. canis was performed by MALDI-TOF MS and 16 S rRNA gene sequence analysis of isolate from subcultured positive aerobic blood culture bottles. Antimicrobial susceptibility testing showed low minimum inhibitory concentrations to amoxicillin-clavulanate, cefotaxime, ceftriaxone, meropenem, and gentamicin. She was treated with combined antibiotic regimen (ceftriaxone, doxycycline) for 14 days, which resulted in total remission of the infection. CONCLUSIONS: Clinicians should recognise H. canis infection risk in patients with recent pet exposure and predisposing factors such as immunodeficiency disorders or diseases that demand immunosuppressive drug therapy. A minimum of two weeks of antibiotic therapy is suggested.