# Bacteremia caused by Helicobacter trogontum indicative of zoonotic infection in a pig farmer: a case report

## TL;DR

A pig farmer developed a rare Helicobacter infection, possibly from zoonotic exposure to pig feces, highlighting its potential as a zoonotic disease.

## Contribution

This case report provides evidence suggesting Helicobacter trogontum may be a zoonotic pathogen.

## Key findings

- H. trogontum was isolated from a pig farmer with bacteremia, linked to possible zoonotic exposure.
- Genome sequencing confirmed H. trogontum infection in a human case.
- H. trogontum has been associated with disease in both animals and humans.

## Abstract

Helicobacter pylori was first isolated from humans in 1983. Since then, >50 Helicobacter species have been registered. Helicobacter trogontum was first isolated from rat colonic mucosa in 1996 and has been isolated from pig feces and the livers of aborted sheep. H. trogontum adheres to and invades human cells and secretes factors that may contribute to disease development.

A 41-year-old woman, who worked on a pig farm, presented to our hospital with sudden-onset headache, nausea, general fatigue, chills, and fever. Plain computed tomography revealed small lymph nodes in the ileocecal region. Intravenous ceftriaxone, vancomycin, and acyclovir were administered for suspected meningoencephalitis. She was discharged from the hospital on day 9 after her symptoms improved. The cerebrospinal fluid culture was negative. However, an aerobic bottle was positive in one of two blood culture sets. Microscopic examination with Gram staining revealed fusiform gram-negative bacteria. Whole genome sequencing of the NHP16-4001 isolate confirmed H. trogontum infection.

Case reports of human infection with H. trogontum are rare. However, H. trogontum has been reported to cause enterocolitis and sepsis in an immunocompetent human, and skin lesions as well as bacteremia in an immunocompromised human. H. trogontum was isolated from pigs, sheep, and mice, suggesting its potential importance as a zoonotic disease. In this case, we hypothesize that bacteremia development was related to contact with pig feces on the patient’s farm. Thus, H. trogontum infection may be considered a zoonosis; however, further reports are warranted for arriving at a definitive conclusion.