Table 5.

10 pitfalls in microbiota studies

Pitfalls	References
1. The term ”microbiota” does not include fungi or viruses	138,139,142
2. Inappropriate usage of microbial taxonomy / classification	143,144
3. The ratio of fecal bacterial taxa underrepresents the gut microbiota	145–147
4. Microbiota changes can be the cause or outcome of disease	3
5. Discrepancy between microbiota studies versus PID	148–152
6. Microbiota influenced by age, gender, and country	3,138,153,154
7. Probiotics/prebiotics are not always beneficial for hosts	156,157
8. Effect of antibiotics treatment on systemic microbiota and immune system	21,82,158,160–163,165
9. FMT methodology and safety	167–170
10. Tailor-made gut microbiota therapy	171–173

Abbreviations: FMT, fecal microbiome transplantation; PID, primary immunodeficiency diseases; and Treg, regulatory T cells