We have read with particular interest the study by Quera et al.1 titled “Fecal microbiota transplantation through colonoscopy in the treatment of recurrent Clostridioides difficile: Experience at a university center”, whose aim was to describe the clinical results of fecal microbiota transplantation (FMT) performed as treatment for recurrent Clostridioides difficile infection (CDI). We would like to make the following observations.

An adequate and detailed description of the methodological aspects of the study by Quera et al.1 should be emphasized. The use of statistical normality tests has been widely discussed. Each has its clear indications, but the Shapiro-Wilk test is recommended over the Kolmogorov-Smirnov test, given that it has been demonstrated to be more powerful and exact. However, we believe it would have been relevant to have given more statistical data on the use of the test employed and the possible limitations for its implementation. For example, for applying the Shapiro-Wilk test, probabilistic sampling is recommended, and the authors provided no further information about their sampling and selection decisions.2

In their study, Quera et al.1 conducted a clinical follow-up of the patients of at least 3 months, post-FMT, and the percentage of successful FMT was defined as the absence of a new episode of CDI for 8 weeks after the procedure. In contrast, Gupta et al.3 describe definitions for clinical and general cure, for evaluating the effectiveness of the procedure. Clinical cure is defined as diarrhea and/or Clostridioides difficile (C. difficile) toxin resolution within a period of 12 weeks or years, and general cure is defined as cure after a single or repeated FMT. One of the inclusion criteria for that study was CDI diagnosis, based on clinical symptoms and C. difficile confirmed through the polymerase chain reaction (PCR) test for toxins A and B, which could be considered post-management control, but is not mentioned in the study by Quera et al.1

Quera et al.1 refer to the limitation in sample size, but it is important to consider special populations, such as immunocompromised patients. In the study by Alrabaa et al.,4 a group of immunocompetent patients was compared with an immunocompromised group and found that all the immunocompetent patients achieved successful cure with FMT, whereas 3 immunocompromised patients experienced failure. A second FMT in those 3 patients was successful in one and failed in the other two. An important predictor of failure in FMT for CDI in immunocompromised patients was pre-FMT antimicrobial exposure.

In conclusion, the relevance and quality of the authors’ research, their findings, and conclusions should be highlighted. We believe a collaborative effort by centers that are highly specialized in surgery and gastroenterology is necessary to develop better and more robust management guidelines in CDI and FMT. The aim of the methodological and population analyses we have made herein is to promote the ongoing implementation of methodological analyses, enabling the journal’s continuous improvement and positioning in the scientific field in Latin America.