The digestive tract of humans and other mammals is inhabited by millions of microorganisms, especially bacteria. This gastrointestinal microbiota is necessary for the good functioning of the digestive process in the host. Recently, Schmulson et al.1 published a review article on irritable bowel syndrome (IBS) and its relation to the intestinal microbiota, as well as to other clinical and therapeutic aspects. We would like to make some comments on that article that may be of use to the medical community.
First of all, the term «flora» is used on various occasions to refer to methane-producing colonic and fecal microbiota, but this term is incorrect despite its common use in human and veterinary medicine. Second, table 3 not only contains a description of molecular methods for characterizing the intestinal microbiota (the title of the table), but also a description of the 16S subunit of ribosomal RNA and the gene that encodes it, which can be confusing to readers unfamiliar with the subject matter. This same table does not identify what the abbreviation rrs stands for, and the sentence on the use of the variability in 16S for distinguishing proximal and distant organisms is only partially valid, due to the uncertainty in today's bacterial molecular taxonomy.2 In addition, table 3 only mentions one (pyrosequencing) of several massive sequencing techniques. This is worth mentioning because this technique will soon disappear from the market and therefore many studies have switched to other techniques, such as that of Ilumina.3 Third, the clinical heterogeneity of IBS and the different methods employed for the study of the intestinal microbiota are without a doubt some of the reasons behind our incapacity to establish a microbial composition belonging to IBS. However, it is necessary to emphasize that our main problem lies in the fact that each individual has a unique basal composition of microorganisms that also have qualitative and quantitative variations that are specific to each individual.4 Fourth, the terms «bifidobacteria», «lactobacilli», «streptococci», and «coliform» are incorrect because in part they do not specify the taxonomic level they belong to. For example, the term «coliform» could refer to specific bacterial species or genera or to a family of Enterobacteriaceae. And finally, it would have been very useful if the article had gone into the subject of the use of probiotics and prebiotics as adjunct therapy in treating IBS. There are commercially available products that contain these nutraceuticals that have not been properly validated in clinical or microbiologic studies. This is important due to the possible adverse effects of these products in the clinical development of IBS.5
The study of the microbiota that inhabits our digestive tract has the great potential for optimizing the treatment of gastrointestinal problems on the part of the medical community. Now is the time to utilize the knowledge and technology available in this area for the benefit of the millions of patients in Mexico that suffer from IBS and other digestive diseases.
Financial disclosureNo financial support was received in relation to this letter.
Conflict of interestThe authors declare that there is no conflict of interest.
Please cite this article as: García-Mazcorro J, Cruz-Valdéz JC, Marroquín-Cardona AG, Sánchez-Casas RM. Microbiota gastrointestinal y síndrome de intestino irritable. Revista de Gastroenterología de México. 2014;79:214–215.