Case Presentation: A 30-year-old man presented for evaluation of multiple episodes of recurrent non-bloody, watery diarrhea and abdominal complaints. Initially seen in clinic, he was well appearing, with normal lab work (CBC, BMP, TSH, TTG IgA, CRP), but given the subacute timeframe of his diarrhea (2-3 weeks) he was referred to a gastroenterologist. Further testing at that time revealed negative HIV, C. diff, and stool lactoferrin, however, his GI pathogen panel (GIPP) was positive for Giardia and Campylobacter. Colonoscopy was negative for colitis. After treatment with azithromycin and tinidazole, he noted resolution of his symptoms, however he presented a few months later with recurrent symptoms of diarrhea, abdominal pain and dehydration. At that time, he was hospitalized for IV fluids and antibiotics, and GIPP was positive for Shigella, which was successfully treated with ciprofloxacin. He presented about six months after this to his PCP, and GIPP was again positive for Giardia. His symptoms again fully resolved after treatment. Throughout this course, the patient denied any camping, international travel or exposure to unclean water sources. He did, however, endorse high risk sexual activity with multiple male partners and was following closely with his PCP for pre-exposure prophylaxis (PrEP). His negative work-up, combined with the fact that he had resolution of his symptoms with treatment between each episode, led to the conclusion that he contracted each episode of gastroenteritis through sexual contact.
Discussion: Enteric pathogens are known to have a fecal oral route of transmission, however it can be easy to overlook sexual contact as a mode of this transmission. In the developed world, infection with enteric pathogens such as Giardia, Campylobacter and Shigella, usually occurs through water and foodborne routes, however studies have also shown them to be spread through sexual contact, particularly in higher risk populations such as men who have sex with men (MSM). Studies reviewing gastroenteritis in MSM in the developed world have found a higher prevalence of these pathogens than in the general population. There has also been evidence of higher rates of antibiotic resistance in certain pathogens (notably Shigella) within the MSM population. Treatment for sexually transmitted enteric diseases (STEDs) requires a twofold approach, involving appropriate treatment of the diarrheal infections and counseling regarding modes of transmission as related to sexual practices. Treatment can be as simple as supportive care if symptoms are mild, but antimicrobial therapies are indicated in more symptomatic or severe cases or to help control spread. It is also important that patients fully understand how their sexual practices can contribute to pathogen spread. PrEP is an important tool to prevent the spread of HIV, but patients must be counseled on the need for barrier protection and safe sex practices, as other sexually transmitted infections, including enteric pathogens, will continue to be passed on in the absence of condoms.
Conclusions: It is important to consider sexual contact as a mode of transmission for enteric pathogens. In high risk populations, such as men who have sex with men, these specific pathogens can be propagated given the smaller community size. Beyond treatment of the infections, frank discussions about safer sex practices are needed to help patients make informed decisions about their sexual health.