Campylobacter fetus Outbreak in Montreal, Quebec, Canada: a Retrospective Analysis

Background: Campylobacter fetus is more likely to cause bacteremia and other extra-intestinal infections than any other species of Campylobacter. To our knowledge, only 2 outbreaks of C. fetus involving a person-to-person transmission are reported in the literature, both of them from adult to newborns. This study describes a space-time aggregate of C. fetus documented in 2014-2015 at a teaching hospital in Montreal, Quebec, Canada.

Methods: A descriptive retrospective study of all the cases of C. fetus at Centre Hospitalier de l’Université de Montréal-Hôpital Saint-Luc from 2014 to 2015 was performed by reviewing medical records. The Montreal Public Health Department also contacted the patients by phone in order to carry out an epidemiological investigation. Strains were analyzed by the Quebec Public Health Laboratory to confirm their identification at the genus and species level, and determine their pulsovar using pulsed-field gel electrophoresis with SmaI and KpnI enzymes.

Results: During a 16-month period ranging from March 2014 to July 2015, 14 patients presenting a C. fetus infection were identified, and 11 of them had a new pulvosar designed p 31. The patients were all men having sex with men (MSM) and 10/11 reported having at-risk sexual activities during the incubation period, like visiting gay bathhouses or sex clubs, and resort to Internet-recruited sex partners. 7/11 were HIV-positive and 8/11 had a prior history of STDs other than HIV. Few other risk factors were identified in these patients (2/11 had a possible food exposure, 1/11 had an animal contact, 1/11 had a recent travel history). Two of the patients presented bacteremia, and one of these two suffered from a ruptured abdominal aortic aneurysm. Even if he was cured from the infection, he died less than 3 months later from terminal kidney disease precipitated by the events after refusing dialysis.

Conclusion: This C. fetus outbreak is the first aggregate presumed to be caused by a sexual transmission in a MSM community. Concordantly to literature, the infection seems associated to an excess of bacteremia and morbidity compared to historic controls of other Campylobacter species.