Review for 10.1186/s12876-023-02863-8 (2023)

Title: Effectiveness of Saccharomyces Boulardii CNCM I-745 Probiotic in Acute Inflammatory
Viral Diarrhoea in Adults. Results of a Randomized Clinical Trial.
Version: 3 Date: 13 Apr 2023
Reviewer's report:
The manuscript written by Marcela AG Salazar-Parra and coauthors reports the results of a
modest study in which the efficacy of Saccharomyces boulardii for the treatment of viral diarrhea
was evaluated. The study was performed on 46 patients and it lacks novelty as similar studies
were previously published.
However, the weakest point of the manuscript is the fact that collected data was only partially
presented, and some data that is not reported is discussed. To be specific, the authors report in
the discussion (lines 266-268) that patients on the probiotic experienced improvement already
at day 3. This data is not presented in the results and Table 2 reports the summarized results
on day 4 and day 8. Similarly, in line 243 it is stated “Patients reported improvement after 4±1
days in the S. boulardii group and after 5±0.95 days in the placebo group (P=0.001).” but it is
not clear based on which data. Also in Table 2, “Improvement” is reported while it is unclear
based on which criterion the improvement is defined. Patients' Global Impression of Change
gives as output a numerical value and it is unclear how the scale value was transformed into an
objective measure of improvement.
My suggestion would be to expand Table 2 so that statistical analysis in all time points is
presented. The patients recorded the data on daily basis (as stated in line 201) which means
that 9 data points per group and parameter should be available. If all this data is presented, the
manuscript would be still modest, but it would be more accurate and complete.
In addition, several points should be addressed.
Line 118, the text that referring to table 1 discusses differences between viral and bacterial
diarrhea, while Table 1 presents patient data (the correct reference for Table 1 is given in line
223). The text and the position of Table 1 should be adjusted.
The randomization of patients is done adequately, but the fact that patients in the probiotic arm
had fewer bowel movements per day than the patients in the placebo arm (7.52±2.3 vs. 8.6±2.4,
p-value 0.12), could be mentioned in the discussion.
In line 152 in the sentence “and the administration of probiotics may help to control bacterial
infection” the word “bacterial” should be replaced with the word “viral”
Line 164 Number of viable cells in the used 200mg commercial probiotic should be reported (in
the abstract and the main text). It is suggested to remove the commercial name of the product.
Line 282, it is reported that patients enrolled in this study did not experience fever, while based
on the data in Table 1 they did. The text should be adjusted
When discussing the limitations of the study, the authors are focused on COVID-19 and possible
overlap with symptoms of viral gastroenteritis. While this could be mentioned, it certainly does
not represent the major limitation of the study (e.g. the relevant limitations are sample size,
scarce data size, etc).
Minor comments
In lines 114-147, It is suggested to use the term microbiota instead of flora, as flora refers to
plants.
Line 158 Please provide a reference about S. boulardii effect on humans instead of animal models
Line 162, “placebo-controlled” should be added after “double-blind”
Line 264 format of the references (9) should be adjusted