Saccharomyces cerevisiae infections in children

A Repertoire of the Less Common Clinical Yeasts

Invasive fungal diseases are a public health problem. They affect a constantly increasing number of at-risk patients, and their incidence has risen in recent years. These opportunistic infections are mainly due to Candida sp. but less common or rare yeast infections should not be underestimated. These so-called "less common" yeasts include Ascomycota of the genera Candida (excluding the five major Candida species), Magnusiomyces/Saprochaete, Malassezia, and Saccharomyces, and Basidiomycota of the genera Cryptococcus (excluding the Cryptococcus neoformans/gattii complex members), Rhodotorula, and Trichosporon. The aim of this review is to (i) inventory the less common yeasts isolated in humans, (ii) provide details regarding the specific anatomical locations where they have been detected and the clinical characteristics of the resulting infections, and (iii) provide an update on yeast taxonomy. Of the total of 239,890 fungal taxa and their associated synonyms sourced from the MycoBank and NCBI Taxonomy databases, we successfully identified 192 yeasts, including 127 Ascomycota and 65 Basidiomycota. This repertoire allows us to highlight rare yeasts and their tropism for certain anatomical sites and will provide an additional tool for diagnostic management.

Catheter-related Saccharomyces cerevisiae Fungemia Following Saccharomyces boulardii Probiotic Treatment: In a child in intensive care unit and review of the literature

Although Saccharomyces boulardii is usually a non-pathogenic fungus, in rare occasions it can cause invasive infection in children. We present the case of an 8-year-old patient in pediatric surgical intensive care unit who developed S. cerevisiae fungemia following probiotic treatment containing S. boulardii. Caspofungin was not effective in this case and he was treated with amphotericin B. We want to emphasize that physicians should be careful about probiotic usage in critically ill patients.

Probiotics for Clostridium difficile-associated diarrhea: focus on Lactobacillus rhamnosus GG and Saccharomyces boulardii

OBJECTIVE

To review the literature on the use of probiotics to treat or prevent recurrences of Clostridium difficile-associated diarrhea (CDAD) by replacing normal gastric flora.

DATA SOURCES

PubMed (1970-March 2007) was searched using the terms probiotics, Clostridium difficile, colitis, diarrhea, prevention, and treatment.

STUDY SELECTION AND DATA EXTRACTION

Case reports, case series, and clinical trials describing the use of probiotics in the treatment or prevention of recurrences of CDAD as primary outcome were included.

DATA SYNTHESIS

A variety of controlled trials, case series, and case reports have evaluated probiotics to treat first or recurrent episodes of CDAD. In addition, a meta-analysis has been conducted to try to determine the role of probiotics in CDAD. In general, most case series and case reports have shown favorable results with Lactobacillus rhamnosus GG or Saccharomyces boulardii. However, other reports have shown lack of benefit. The meta-analysis showed that these probiotics may be useful in treating or preventing recurrences of CDAD. Nonetheless, the heterogeneity of the studies makes definite conclusions difficult. In addition, several cases of bacteremia or fungemia associated with probiotic use have been reported, particularly in the last decade. Patients most commonly affected by these complications are immunosuppressed. Unfortunately, these are also the patients more likely to have severe CDAD or are at risk for recurrences.

CONCLUSIONS

Additional experience with and study of probiotics are warranted due to numerous unanswered questions. Given the potential for complications in debilitated and immunosuppressed patients, the risks may outweigh benefits, and rational antibiotic use may be a better option to prevent a first episode or recurrence of CDAD.

Correlation between Saccharomyces cerevisiae DNA in intestinal mucosal samples and anti-Saccharomyces cerevisiae antibodies in serum of patients with IBD

AIM: To investigate the correlation between ASCA and presence of mucosal S. cerevisiae DNA in a population of CD, ulcerative colitis (UC) patients and controls.

METHODS: S. cerevisiae-specific primers and a fluorescent probe were designed for a 5’ exonuclease real time PCR (TaqMan^TM) assay, which is a homogenous system using a fluorescent-labelled probe for the detection of PCR product in real time. We analyzed the relation of the PCR results with the ASCA findings in a group of 76 inflammatory bowel disease (IBD) patients (31 CD, 45 UC) and 22 healthy controls (HC).

RESULTS: ASCA (IgA or IgG) were positive in 19 (61%) patients with CD, 12 (27%) with UC and none of the HC. PCR amplification was inhibited and excluded from the final results in 10 (22%) UC patients, 7 (22%) CD patients, and 6 (30%) HC. In only 15 of the mucosal samples, S. cerevisiae DNA was detected by real time PCR, including 7 (29%) in CD, 7 (19%) in UC, 1 (6%) in HC. In 4 CD and in 4 UC patients, ASCA and mucosal S. cerevisiae were positive. Mucosal S. cerevisiae was present in combination with negative ASCA IgA and IgG in 3 UC, and 3 CD patients.

CONCLUSION: We conclude that since the presence of S. cerevisiae in colonic mucosal biopsy specimens is very rare, ASCA is unlikely to be explained by continuous exposure to S. cerevisiae in the mucosa. Therefore, ASCA formation must occur earlier in life and levels remain relatively stable thereafter in immunological susceptible persons.

Invasive Saccharomyces infection: a comprehensive review

BACKGROUND

Saccharomyces cerevisiae (also known as "baker's yeast" or "brewer's yeast") is mostly considered to be an occasional digestive commensal. However, since the 1990s, there have been a growing number of reports about its implication as an etiologic agent of invasive infection. A particular feature of such infections is their association with a probiotic preparation of Saccharomyces boulardii (a subtype of S. cerevisiae) for treatment various diarrheal disorders.

METHODS

We collected published case reports, through May 2005, of invasive Saccharomyces infection by use of a Medline query. Epidemiological and clinical charts and therapeutic strategies were analyzed.

RESULTS

We found 92 cases of Saccharomyces invasive infection. Predisposing factors were similar to those of invasive candidiasis, with intravascular catheter and antibiotic therapy being the most frequent. Blood was the most frequent site of isolation (for 72 patients). S. boulardii accounted for 51.3% of fungemias and was exclusively isolated from blood. Compared with patients infected with S. cerevisiae, patients infected with S. boulardii were more frequently immunocompetent and had a better prognosis. Saccharomyces invasive infection was clinically indistinguishable from an invasive candidiasis. Overall, S. cerevisiae clinical isolates exhibited low susceptibility to amphotericin B and azole derivatives. However, global outcome was favorable in 62% of the cases. Treatment with intravenous amphotericin B and fluconazole, in combination with central vascular catheter removal, were effective therapeutic options.

CONCLUSION

Saccharomyces organisms should now be added to the growing list of emerging fungal pathogens. Special caution should be taken regarding the use of S. boulardii probiotic preparations.

Saccharomyces cerevisiae fungemia: an emerging infectious disease

BACKGROUND

Saccharomyces cerevisiae is well known in the baking and brewing industry and is also used as a probiotic in humans. However, it is a very uncommon cause of infection in humans.

METHODS

During the period of 15-30 April 2003, we found 3 patients with S. cerevisiae fungemia in an intensive care unit (ICU). An epidemiological study was performed, and the medical records for all patients who were in the unit during the second half of April were assessed.

RESULTS

The only identified risk factor for S. cerevisiae infection was treatment with a probiotic containing Saccharomyces boulardii (Ultralevura; Bristol-Myers Squibb). This probiotic is used in Europe for the treatment and prevention of Clostridium difficile-associated diarrhea. The 3 patients received the product via nasograstric tube for a mean duration of 8.5 days before the culture result was positive, whereas only 2 of 41 control subjects had received it. Surveillance cultures for the control patients admitted at the same time did not reveal any carriers of the yeast. Strains from the probiotic capsules and the clinical isolates were identified as S. cerevisiae, with identical DNA fingerprinting. Discontinuation of use of the product in the unit stopped the outbreak of infection. A review of the literature identified another 57 cases of S. cerevisiae fungemia. Overall, 60% of these patients were in the ICU, and 71% were receiving enteral or parenteral nutrition. Use of probiotics was detected in 26 patients, and 17 patients died.

CONCLUSIONS

Use of S. cerevisiae probiotics should be carefully reassessed, particularly in immunosuppressed or critically ill patients.

Saccharomyces boulardii induced sepsis: successful therapy with voriconazole after treatment failure with fluconazole

Saccharomyces boulardii is frequently used for prevention and treatment of all forms of diarrhoea. We report the case of a 19-y-old white male with an underlying severe neurological disease, who developed a fungal sepsis after prophylactic application of a drug containing S. boulardii. Initial treatment with fluconazole was not successful. After the application of voriconazole, the sepsis resolved completely. This is the first clinical report of a successful treatment of Saccharomyces sepsis with voriconazole.

Saccharomyces cerevisiae-associated diarrhea in an immunocompetent patient with ulcerative colitis

Infectious diarrhea is common in cases of ulcerative colitis (UC), caused by resistance to treatment. In particular, it has been associated with cytomegalovirus or infection has rarely been observed in human beings, but has never been seen in immunocompetent patients. We report a case of intestinal infection presenting as acute diarrhea in a patient with a 10-year history of UC who was never treated with immunosuppressants.

Saccharomyces cerevisiae fungemia after Saccharomyces boulardii treatment in immunocompromised patients

Saccharomyces cerevisiae is widely used as a probiotic compound. Clinical data suggest that this agent is safe and effective. We report two cases of fungemia caused by S. cerevisiae occurring in immunosuppressed patients treated orally with S. boulardii Molecular typing confirmed clonality in isolate strains from patients and the capsule. Physicians caring for immunosuppressed patients must be aware of this potential serious complication of probiotic use.