Confused by Weissella confusa Bacteremia

LETTER

The recent photo quiz and discussion of Weissella confusa bacteremia by Vasquez et al. (1, 2) was interesting. The authors proposed several possible routes of infection and related factors, including line infection, dependency on total parenteral nutrition, and altered gut flora associated with multiple prior abdominal surgeries related to Crohn's disease.

As the patient had a history of prior use of probiotic therapy, the probiotics could also be a potential source of the bacteremia. Many probiotic preparations contain lactobacilli. Weissella strains may be confused with lactobacilli and have been studied as candidate probiotic microorganisms (3). It is plausible that the probiotic ingested by the patient contained W. confusa, either deliberately or as a result of misidentification as a Lactobacillus species. In their discussion, the authors do not mention the name of the probiotic or if it was tested for the presence of Weissella. Other probiotic microorganisms, both bacterial and fungal, have been associated with blood-borne infections (3–5). In these cases, a postulated mechanism of infection was intestinal translocation of the ingested microorganisms.