It’s time to develop more effective ways to control and prevent sexually transmitted gut infections, urge the authors of an article appearing today in Clinical Microbiology Reviews, a journal of the American Society of Microbiology
“Global emergence of several multidrug-resistant gut pathogens and the potential for crossover transmissions among different at-risk populations underscores the importance of prompt diagnosis, appropriate treatment, and the need to consider community-level education and testing,” they wrote.
The article’s senior author is Dr. Ferric C. Fang, professor of microbiology, laboratory medicine and pathology at the University of Washington School of Medicine. In addition to his research, he oversees the clinical microbiology laboratory at Harborview Medical Center in Seattle.
What has become particularly troubling is that these infections are becoming harder to treat and can persist for longer periods of time. In their review, Fang and his colleagues discuss several sexually transmitted enteric pathogens that have become extremely multi-drug resistant. Because of the ease of international travel, the transmission of gastrointestinal superbugs is no longer an isolated problem but a global health concern.
Researchers and public health officials have recognized since the late 1960s and early 1970s that enteric infections can be sexually transmitted, and that this route of spread occurs more frequently among men who have sex with men. (Enteric refers to the lower digestive tract.)
Gut infections among this population are “the newest of the old diseases,” their article says.
Public health responses to enteric disease outbreaks sometimes fall between the cracks, the authors explained. Tracing the origins of outbreaks typically involves looking into food-borne exposures. Health care providers may overlook the possibility of sexual transmission, while programs to control sexually transmitted diseases typically focus on traditional causes like syphilis and gonorrhea. Also, medical data available to epidemiologists may lack information about sexual history.
A wide variety of pathogens can cause enteric infections in men who have sex with men, but the illnesses have similar symptoms. All these disease agents, whether bacteria, viruses, amoebas or other protozoans, as well as additional kinds of parasites, can set off diarrhea.
Fang pointed out that advances in molecular testing of patient samples have improved detection of causative organisms and their genetic strains. These more sensitive tests can assist in determining the most appropriate treatment, as well as help in efforts to trace transmission.
Fang and colleagues reviewed a dozen recognized STEI pathogens. These include Campylobacter, diarrhea-causing strains of Escherichia coli, Salmonella, Shigella, Entameoba histolytica, Giardia, Strongyloides, Cryptosporidium, Cystoisospora, Microsporidia, and hepatitis A virus. For a few other pathogens, the role of sexual activity in their transmission is uncertain. These include Clostridioides (Clostridium) difficile, a pathogen that can take up long-term residence in the gut, Brachyspira, a spirochete bacterium that colonizes the intestines, and hepatitis E and other enteric viruses.
The researchers noted that people’s behavior, rather than their HIV or immune status, appears to be driving the rise in sexual transmission of enteric pathogens, which has taken off since the end of the COVID pandemic.
The scientists were initially concerned that HIV or drugs used for the prevention of HIV, or antibiotics for pre- or post-exposure to other types of sexually transmitted illnesses, might be major factors. But except for protozoal infections, there appears to be no difference in the rate of enteric pathogens affecting HIV-positive or HIV-negative men.
Oral-anal contact, or rimming, is the primary way that enteric infections are spread during sexual activity, the review found. The authors add that recent cultural changes have created more opportunities for gut pathogens to find new hosts. Sexual encounters with new partners are readily made through online sites and digital connections. The use of condoms and other safe-sex barriers is declining as prophylactic medications against AIDS, syphilis and gonorrhea have become more readily available. Chemsex, or the use of recreational drugs to enhance sexual activity, can also lower inhibitions.
The authors expressed hope that education can make people more aware that serious enteric infections can be acquired and spread from sexual activity. Safe-sex practices and refraining from sexual contact for two weeks after an episode of diarrhea can prevent others from becoming infected and thereby break the chain of transmission.
Men who have sex with men who are more likely to acquire sexually transmitted enteric infections tend to be younger, urban, travel internationally and have wider sexual networks.
Enteric infections may also move back and forth between different population groups in a community, the article noted. People experiencing homelessness are at risk if they live in unsanitary conditions and exchange sex for money or other needs. People who are immunocompromised are also more susceptible to these infections and their more serious complications.
What has become particularly troubling is that these infections are becoming harder to treat and can persist for longer periods of time. In their review, Fang and his colleagues discuss several sexually transmitted enteric pathogens that have become extremely multi-drug resistant. Because of the ease of international travel, the transmission of GI superbugs is no longer an isolated problem but a global health concern.
Other authors of this article, which is the first comprehensive review of sexually transmitted enteric infections, also called STEI, are Drs. Kira Newman of the University of Michigan, Gretchen Snoeyenbos Newman of Wayne State University in Detroit, and Chase A. Cannon, medical director of the Public Health Seattle & King County STD Clinic and assistant professor of medicine, Division of Allergy and Infectious Disease, at the UW School of Medicine.
The researchers’ work was supported by the National Institutes of Health (grants AI50041 and AI60103), the American College of Gastroenterology, and Pfizer.