Lactobacillus rogosae-Erakina

Holdeman and Moore first identified and described Lactobacillus rogosae in 1974.

A brief introduction to Lactobacillus rogosae:

It is a well-known fact that the ubiquitously present lactobacilli bacteria are efficient microbial probiotics that not only improve digestion and immunity but also maintain the pH and balance of the gastrointestinal tract.

These bacteria have been studied for decades, and during the research process, several new bacteria belonging to this family have been identified and isolated. However, at the same time, several bacteria have also been misidentified as lactobacilli bacteria despite not being so. One such case is that of Lactobacilli rogosae. It has not been confirmed, but there is a dispute over the taxonomic classification of this bacterial species, with some researchers speculating that it might  belong to the family ‘Lachnospira’.

This misidentification can be attributed to the bacterial species’ close similarity to bacteria belonging to the Lactobacillus family.

Physiological and morphological characteristics:

• Obligately anaerobic microorganisms
• Gram-positive in nature
• Non-spore-forming bacteria
• Both motile and non-motile strains were identified.
• Rod-shaped 
• They occur both singly and in pairs or short chains.
• Fermentation products of this bacterial species include small amounts of acetic and lactic acid, along with traces of lactate and succinate.

Microscopic view of a species of Lactobacillus

Colony characteristics:

• The profile of the colony observed was in the shape of a raised convex.
• Colonies are circular, with diameters ranging between 0.5 and 1.0 mm.
• The edges are smooth.
• Colonies are translucent but can also be opaque.
• Colonies can either be tan or colourless.

Culturing of Lactobacillus bacterial species

The Lactobacillaceae family:

This family of bacteria is present ubiquitously in the microenvironments of both humans and animals. They are gram-positive and are characterised by their rod shape and ability to produce lactic acid as a product of glucose fermentation. LAB are commonly used as probiotics. They possess the ability to metabolise several compounds in the human digestive system and, hence, play a major role in the maintenance of gut health and balance. Bacteria belonging to this genus are usually non-spore- forming and non-motile. They are rarely pathogenic and form symbiotic relationships with other animals.

Beneficial functions carried out by Lactobacillus bacteria:

• Metabolism of tryptophan in the gastrointestinal tract.
• Maintenance of pH in the urogenital tract.
• Fermentation of commercial products such as alcoholic beverages and yoghurt.
• Pathogen neutralisation and immobilisation; antibiotic abilities.

The presence of various Lactobacillus species in the gut

The Lachnospiraceae family:

This bacterial family is characterised by the presence of both spore-forming and non-spore-forming bacteria which are obligate anaerobes, meaning they can only survive in anaerobic conditions. They are abundantly present in the microbiota of both humans and animals.

Beneficial functions carried out by Lachnospira bacteria:

• Improve gut health and digestion.
• Maintain pH in the rumen of herd animals.
• Ability to mitigate cancer of the colon.
• The production of ethanol and acetic acid as fermentation products make it an important part of industrial plants.
• Ability to digest or ferment plant polysaccharides into simpler forms.

It is important to note that recent studies have shown that these bacteria also contribute to the manifestation of diabetes in susceptible mouse populations.

Microscopic view of a species of Lachnospiraceae.

Conclusion

The physiology and morphology of Lactobacillus rogosae exhibit a close resemblance to that of the bacterial species belonging to the family Lachnospiraceae. Hence, there have been discussions as to which family this bacterial species belongs to, even though it has been classified under the genus Lactobacillus. This bacterial species is present abundantly in the human gut and has not exhibited any sort of pathogenicity. For now, it can be concluded that this bacterial species has formed a symbiotic relationship with the host and does not produce any ill-effects.

Deepika Thilakan

30/05/2022