TL;DR version:

Is there any proof of correlation (or lack thereof) between receptive rectal intercourse and raised risks for bacterial endocarditis? [UPDATE] Does it hold even for protected sex, given that said bacteriae may come from receiver's gut flora?

The long version:

Once I've watched a short video clip (like those sent around in social media apps) of a woman claiming that there is a higher risk of bacterial endocarditis in patients with a history of receptive anal intercourse.

The woman, whose name is not stated in said clip, claimed to be a physician and gives a sort of informal lecture to an unindentified audience recalling a story of when she was a resident at Gafrée & Guinle University Hospital in Rio de Janeiro, Brazil (specialized in STD).

She tells that back then she and colleagues were given the task of finding which were the opportunistic infections related to AIDS, and among them they listed infective bacterial endocarditis, to which their tutor replied it was not, that they should come back to field and try to correlate endocartitis cases with past sexual behaviors of patients. She claims they found a high correlation with patients that usually received anal intercourse.

She then goes further to show the causal nexus from how the act favors the infection (basically the retal lining being so thin so that to be easily damaged during the act, and enterococci -- [UPDATE] from one's own gut flora -- then enter the blood stream and infect the cardiac valves).

[the "lecture" goes on with other "problems" associated with receptive anal intercourse, saying things about dysplasias and cancer and so on, not relevant for this question]

At the very end of her presentation, to much of our dismay, she goodbyes the audience with "Hallelujah brethren" (a common utterance among brazilian neo-charismatic religous groups), that sort of gave away what the audience was.

Given how morally charged the subject is (and for both sides, those condemning such intercourses and those condoning or even promoting them, leaving a narrow no-man's-land inbetween) and the religious environment where the audience was given, I'm very skeptical to the legitimacy of her story.

I couldn't find any legit source of such claims, and the said lecture was informal enough to not care to give quantitative figures of her claims or physician/researcher names.

I'd like to know:

  1. Is there any research done on this?

  2. Is there any research of how successful are enterococci thriving in an otherwise healthy [immunocompetent] individual's bloodstream and fixating in cusps?

  3. Is the correlation statistically significant?

  4. How heightened is the risk for a patient already at risk for endocarditis (valve malformations)?

  5. Is it possible that the correlation she claims to have seen only affect people with depressed immunity?

1 Answer 1


It is a known fact that STDs are more easily transmitted by unprotected anal intercourse. As some STDs are known to (rarely) cause endocarditis, it seems plausible to me that unprotected anal intercourse increases the risk of an endocarditis.

I could, however, find no statistical analysis on the relationship between (receptive) anal intercourses and endocarditis.

The bacterium causing gonorrhoea is known to lead to endocarditis in rare cases:

Untreated infection with gonococcus may lead to transient bacteremia, arthritis, or dermatitis. More severe sequelae such as endocarditis and meningitis are rare.

Whitlow CB. Bacterial sexually transmitted diseases. Clin Colon Rectal Surg. 2004;17(4):209-214. doi:10.1055/s-2004-836940

In ascending infections, the posterior part of the urethra may become infected (posterior gonorrheal urethritis). Patients may also develop prostatitis, vesiculitis, funiculitis, epididymitis, Cowperitis, cavernitis, or even gonococcal sepsis, perihepatitis gonorrhoica, endocarditis, meningitis, or gonarthritis.

Sexually Transmitted Infections

Here is a case report of a patient with HIV who got infected by Enterococci and developed an endocarditis.

Bottom line: Be safe and always use protection

  • Thanks for your answer. But the whole point in the question is that even protected sex, for the anal receiving party, may still pose some risks. I'd like to know how worrisome one should be. Yet I think the whole story is moot. I mean, not by the nexus causalis itself, which seems sound, but for the probabilities involved, which maybe very low, given that nobody is talking about that.
    – rslemos
    Aug 11, 2020 at 22:50
  • 1
    I've updated the question to make it clear that the point is the risk even for protected sex. Actually, for that matter, if the correlation holds, the heightened risk would be present even with [disinfected] sex toys.
    – rslemos
    Aug 12, 2020 at 0:33

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