Probiotic supplement caused man's fatal infection in rare case

In a rare case, a man died of a bloodstream infection that was triggered by a probiotic supplement.

These blood infections, known as probiotic-related bacteremia, are a known risk of taking probiotics, or live microorganisms that are meant to benefit the body in some way — for example, by repopulating the gut microbiome after a person takes antibiotics. Probiotic-related infections happen only occasionally, but having a weakened immune system or abnormalities in the gastrointestinal tract may raise the risk.

Various case reports have described incidents in which hospitalized patients ended up with bacteria in their blood after being given probiotics. More-detailed studies, including one published in 2019, have uncovered genetic evidence that the exact bacteria in a given probiotic were the culprit behind a patient's infection.

In the man's recent case, a genetic analysis confirmed that bacteria from a probiotic triggered his fatal infection. A description of the man's case was published Aug. 3 in the journal BMJ Case Reports. It noted that the patient had an extensive medical History, which likely raised his risk of this rare occurrence.

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The case began when the man, who was in his 70s and lived in Japan, was found collapsed on the floor of his home and then brought to an emergency room. Doctors found that the patient had severe metabolic acidosis, in which acid builds up in the blood. This condition had been brought on by a lung infection, a kidney injury and, potentially, heavy drinking, as the man had a History of alcohol dependence.

Further tests revealed that the man was positive for SARS-CoV-2, the virus behind COVID-19. He was transferred to an intensive care unit and received breathing support; a blood thinner; a steroid to combat inflammation; and tocilizumab, which blocks an inflammatory protein. He also got antibiotics, as doctors suspected and then confirmed that he also had a bacterial infection at the same time.