Incidence and outcomes of bloodstream infections among hematopoietic cell transplant recipients from species commonly reported to be in over-the-counter probiotic formulations

Transpl Infect Dis. 2016 Oct;18(5):699-705. doi: 10.1111/tid.12587. Epub 2016 Sep 21.


Background: Probiotic supplementation has been promoted for numerous health conditions; however, safety in immunosuppressed patients is unknown. We evaluated bloodstream infections (BSIs) caused by common probiotic organisms in hematopoietic cell transplant recipients.

Methods: All blood culture (BC) results from a cohort of hematopoietic cell transplant recipients transplanted at Fred Hutchinson Cancer Research Center in Seattle, Washington, between 2002 and 2011 were reviewed. Patients with at least 1 positive BC for common probiotic organisms (Lactobacillus species, Bifidobacterium species, Streptococcus thermophilus, and Saccharomyces species) within 1 year post hematopoietic cell transplantation (HCT) were considered cases. Data were collected from center databases, which contain archived laboratory data, patient demographics, and clinical summaries.

Results: A total of 19/3796 (0.5%) patients developed a BSI from one of these organisms within 1 year post HCT; no Bifidobacterium species or S. thermophilus were identified. Cases had a median age of 49 years (interquartile range [IQR]: 39-53), and the majority were allogeneic hematopoietic cell transplant recipients (14/19, 74%). Most positive BCs were Lactobacillus species (18/19) and occurred at a median of 84 days (IQR: 34-127) post transplant. The incidence rate of Lactobacillus bacteremia was 1.62 cases per 100,000 patient-days; the highest rate occurred within 100 days post transplant (3.3 per 100,000 patient-days). Eight patients (44%) were diagnosed with acute graft-versus-host disease of the gut prior to the development of bacteremia. No mortality was attributable to any of these infections.

Conclusion: Organisms frequently incorporated in available over-the-counter probiotics are infrequent causes of bacteremia after HCT. Studies evaluating the use of probiotics among high-risk patients are needed.

Keywords: Lactobacillus; bacteremia; fungemia; hematopoietic cell transplant; over-the-counter; probiotic.

MeSH terms

  • Adult
  • Aged
  • Bacteremia / blood
  • Bacteremia / epidemiology*
  • Bacteremia / microbiology*
  • Bifidobacterium / isolation & purification
  • Bifidobacterium / pathogenicity
  • Blood Culture
  • Child
  • Child, Preschool
  • Female
  • Graft vs Host Disease / complications
  • Graft vs Host Disease / epidemiology
  • Hematopoietic Stem Cell Transplantation / adverse effects*
  • Humans
  • Immunosuppression Therapy / adverse effects*
  • Incidence
  • Lactobacillus / isolation & purification
  • Lactobacillus / pathogenicity*
  • Male
  • Middle Aged
  • Nonprescription Drugs / adverse effects*
  • Probiotics / adverse effects*
  • Probiotics / analysis
  • Retrospective Studies
  • Saccharomyces cerevisiae / isolation & purification
  • Saccharomyces cerevisiae / pathogenicity
  • Streptococcus thermophilus / isolation & purification
  • Streptococcus thermophilus / pathogenicity
  • Transplant Recipients
  • Transplantation, Homologous / adverse effects
  • Young Adult


  • Nonprescription Drugs