In 2020, the scientific community initiated a massive reorganization of the widely known Lactobacillus genus, impacting over 250 species. This was a historic change, driven by decades of new genomic and genetic research that revealed the original genus was far too diverse and complex to be grouped under a single name. The reclassification resulted in the creation of 23 new genera within the family Lactobacillaceae, bringing order to a complex bacterial taxonomy. Among the species affected was the well-regarded probiotic, Lactobacillus fermentum, which is now known as Limosilactobacillus fermentum.
The shift from Lactobacillus fermentum to Limosilactobacillus fermentum
The change from Lactobacillus fermentum to Limosilactobacillus fermentum is a direct result of the comprehensive taxonomic revision. Scientists utilized advanced whole-genome sequencing to more accurately delineate bacterial species based on their genetic relatedness and physiological traits. The new genus, Limosilactobacillus, is now home to species with nomadic or environmental lifestyles, and those adapted to the intestinal tract of vertebrates. This reclassification does not change the probiotic properties or safety of L. fermentum, but it provides a more accurate scientific name based on modern taxonomy. For consumers, this means that some product labels may still refer to the old name, but the strain and its benefits remain the same. Regulatory bodies like the US FDA and Health Canada have adopted the new nomenclature, confirming its scientific validity.
Why was the Lactobacillus genus reclassified?
Before 2020, the genus Lactobacillus was a scientific "catch-all" for many gram-positive, lactic acid-producing, rod-shaped bacteria. It contained numerous species with significant genetic and phenotypic diversity, making consistent classification and comparison challenging. The reclassification was necessary for several key reasons:
- Enhanced scientific accuracy: Whole-genome sequencing showed that many species within the old genus were not closely related enough to share a single genus name, which is a fundamental rule of bacterial nomenclature.
- Better resolution for research: By splitting the genus into more genetically cohesive groups, scientists can more effectively study and understand the link between specific bacteria's genes, metabolism, and ecology. This provides higher resolution for metagenomic studies.
- Facilitated regulatory processes: A more precise classification system aids regulatory agencies like the European Food Safety Authority (EFSA) and the US Food and Drug Administration (FDA) in assessing the safety and properties of probiotic strains.
- Clarification for industry: The new system helps in the development and marketing of products containing probiotics by providing a clear, updated naming standard.
Implications for consumers and the probiotic industry
This taxonomic update has important, though mostly administrative, implications. For consumers, the biggest change is seeing a new name on product labels. However, the probiotic strain itself and its documented health benefits have not changed. For example, a product containing Limosilactobacillus fermentum CECT5716 is the same beneficial probiotic formerly labeled as Lactobacillus fermentum CECT5716. The probiotic industry is in the process of updating product labels to reflect the new nomenclature, but there may be a transition period where old and new names co-exist.
| Feature | Old Name: Lactobacillus fermentum | New Name: Limosilactobacillus fermentum |
|---|---|---|
| Genus | Lactobacillus | Limosilactobacillus |
| Species | fermentum | fermentum |
| Reclassification Date | Before 2020 | April 2020 |
| Classification Method | Traditional methods based on morphology and physiology | Modern genomic and polyphasic approaches |
| Strain ID | Remained the same (e.g., CECT5716) | Remained the same (e.g., CECT5716) |
| Ecological Niche | Broadly defined, includes food and human sources | More precisely defined as nomadic or vertebrate-adapted |
| Probiotic Effects | Unchanged, depends on specific strain | Unchanged, depends on specific strain |
Conclusion: Embracing the new name
The reclassification of Lactobacillus fermentum to Limosilactobacillus fermentum is a testament to the continuous evolution of scientific knowledge. Driven by advanced genomic analysis, this change provides a more accurate and robust taxonomic system for a diverse group of bacteria. While the new name may cause some initial confusion for consumers, it's important to remember that the properties, efficacy, and safety of the probiotic strains remain completely unchanged. The transition to the new nomenclature reflects a commitment to scientific precision and will benefit future research and product development in the field of probiotics. By understanding the reasons behind this change, we can all embrace the new, more accurate name and continue to appreciate the beneficial role of Limosilactobacillus fermentum.
The process behind the taxonomic change
The 2020 taxonomic revision, published in the International Journal of Systematic and Evolutionary Microbiology, was a monumental undertaking by an international group of scientists. Their work, based on comparative genome analysis, identified distinct genetic clusters within the former Lactobacillus genus. Instead of a single, highly heterogeneous genus, they defined 23 new genera that better reflect the evolutionary relationships and physiological characteristics of the bacteria. This rigorous process ensures that the new names are not arbitrary but are based on sound, modern scientific evidence, creating a more logical and informative classification system for the future.
What is the new name for Lactobacillus fermentum?
The new name for Lactobacillus fermentum is Limosilactobacillus fermentum.
What are some other examples of Lactobacillus reclassification?
Other examples include Lactobacillus casei becoming Lacticaseibacillus casei and Lactobacillus plantarum becoming Lactiplantibacillus plantarum. Some species, like Lactobacillus acidophilus, remained in the genus Lactobacillus.
Does the name change alter the probiotic's effects?
No, the name change is purely taxonomic and does not alter the biological effects, safety, or properties of the specific probiotic strain. A strain like Limosilactobacillus fermentum CECT5716 is the same microorganism as the one previously called Lactobacillus fermentum CECT5716.
Why did the reclassification happen in 2020?
The reclassification occurred in 2020 due to advancements in whole-genome sequencing technologies, which allowed scientists to analyze the genetic diversity of the genus more accurately and recognize that it was too heterogeneous.
How should I refer to the new name?
For most purposes, it's sufficient to use the new name, Limosilactobacillus fermentum. During the transition period, using both the new name with the former name in parentheses, such as Limosilactobacillus fermentum (formerly Lactobacillus fermentum), can help avoid confusion.
Where can I find a list of all reclassified Lactobacillus species?
Official publications detailing the taxonomic revision, such as the paper by Zheng et al. (2020) in the International Journal of Systematic and Evolutionary Microbiology, contain comprehensive lists. The International Scientific Association for Probiotics and Prebiotics (ISAPP) also provides updated information.
How does this affect products containing Lactobacillus fermentum?
Probiotic products containing this species will gradually update their labeling to reflect the new name, Limosilactobacillus fermentum. You may see older stock with the previous name during this transition. Always check the specific strain number (e.g., CECT5716) for consistency.
