‘Strong likelihood’ Campylobacter can be transmitted via sexual contact
Study findings from Denmark strongly indicate that Campylobacter can be sexually transmitted, said researchers, who found that the odds of infection were 14 times higher among men who have sex with men compared with control subjects.
“I was made aware of an outbreak of Campylobacter among men who have sex with men (MSM) in Norway. A Norwegian colleague explained that these outbreaks happen from time to time,” Katrin Gaardbo Kuhn, PhD, assistant professor of biostatistics and epidemiology in the University of Oklahoma Hudson College of Public Health, told Healio.
“I became curious as to whether the outbreaks could also reflect that sporadic transmission of Campylobacter occurs, both among MSM but also [among] the general population,” Kuhn said. “Because the Danish surveillance system for notifiable infectious diseases is very well developed and collects information on certain exposures related to a notified infection, it was possible to do this study using Danish data.”
Kuhn and colleagues performed a national retrospective, individually matched case-control study of men aged 18 years or older in Denmark between 2010 and 2018. They used MSM as case-patients and infections with Campylobacter species, Shigella species, or Salmonella species as exposures. They then matched each MSM case patient with three to five randomly selected controls from the same clinical infectious disease database by age and municipality of residence.
In all, the study included 4,186 men who acquired a notifiable enteric disease through MSM contact between Jan. 1, 2010, and Dec. 31, 2018, and 15,250 randomly selected matched male controls. Overall, 76% of notifications were for Campylobacter infections: 55% for Campylobacter jejuni, 4% for Campylobacter coli, and 40% for other Campylobacter species with no species reported. Among MSM, a total of 132 Campylobacter, three Salmonella, and 64 Shigella infections were reported during the study period, whereas 74 Campylobacter, 44 Salmonella, and four Shigella infections were observed in the control group.
Overall, the study demonstrated that the rate of Campylobacter infection was 14 times higher in MSM compared with the rate in control subjects (modified OR = 14; 95% CI, 10-21) a finding that the researchers said is comparable to Shigella, which is known to be transmitted through sexual contact.
Additionally, the study showed that MSM case-patients who were infected with Campylobacter were significantly less likely to have acquired their infection abroad compared with controls (P < .001), which was not the case for Salmonella or Shigella.
“Our findings indicate a strong likelihood that Campylobacter can be transmitted during sexual contact,” Kuhn and colleagues wrote.
Kuhn explained that they used the word “indicate” because the most solid evidence would come from a biological study or direct, measurable evidence of transmission. However, these studies are not possible, leaving observational studies to find the evidence.
“The clinical take-home message is primarily one for public health professionals and physicians: With some sexual practices, there is an additional risk of becoming infected with a gastrointestinal pathogen,” Kuhn said. “We need to talk to our patients about these risks. Although Campylobacter is not a very serious disease, it makes people feel sick for several days or weeks and not being able to work or take care of their other commitments. As with many other infectious diseases, this, in turn, has the most severe impact on those who are already the most vulnerable in our society.”