Researchers at the Weizmann Institute in Israel tested that assumption directly, comparing people and mice who took a standard multi-strain probiotic after antibiotics against those who recovered on their own or received their own banked gut bacteria back.
Probiotics did colonize the gut, but they got in the way: compared with spontaneous recovery, the probiotic strains produced a markedly delayed and persistently incomplete return of each person's original stool and mucosal microbiome, lasting months. A transplant of the person's own pre-antibiotic bacteria, by contrast, restored the native microbiome almost completely within days.
The result ran counter to how probiotics are marketed and prescribed after a round of antibiotics. The autologous transplant approach is not something most people can access, since it requires banking a stool sample before taking antibiotics in the first place, so the practical advice coming out of the study was narrower than the finding: probiotics are not a neutral add-on.
Read the original study
Suez et al., Cell, 2018 · doi.org/10.1016/j.cell.2018.08.047
The fix got in the way of the recovery.
Source
- Suez, J., Zmora, N., Zilberman-Schapira, G., Mor, U., Dori-Bachash, M., Bashiardes, S., Zur, M., Regev-Lehavi, D., Ben-Zeev Brik, R., Federici, S., Horn, M., Cohen, Y., Moor, A. E., Zeevi, D., Korem, T., Kotler, E., Harmelin, A., Itzkovitz, S., Maharshak, N., . . . Elinav, E. (2018). Post-Antibiotic Gut Mucosal Microbiome Reconstitution Is Impaired by Probiotics and Improved by Autologous FMT. Cell, 174(6), 1406–1423.e16. https://doi.org/10.1016/j.cell.2018.08.047