Lactobacillus helsingborgenesis is a novel bacterial strain that was isolated in Helsingborg, Sweden from the stomach of Apis mellifera.

The genus Lactobacillus: An overview


Bacterial species that belong to the genus Lactobacillus are present ubiquitously in the human body. They form a significant part of the human microbiota and are found in the gastrointestinal and urogenital tracts. Lactobacillus species are also commonly found in the rumen of ruminant animals such as cattle and goats. They play an important role in the improvement of digestion and maintenance of gut health and pH in both humans and animals. These bacterial species are known for their ability to form biofilms that help them survive and thrive in the harsh conditions of the human body. Such bacterial species are commensals and usually form symbiotic relationships with their hosts. They are not known to have any detrimental effects on the hosts that they inhabit. Lactobacillus bacteria, however, do cause dental caries. 

Due to their ability to maintain gut health and pH, lactobacillus species are also commonly consumed as probiotics. They primarily help in treating indigestion, vaginal infections, diarrhoea and skin infections such as eczema. Hence, it can be concluded that bacterial species belonging to this genus provide a multitude of benefits in the context of human health and well-being.

Common probiotic-containing superfoods.

Physiology and morphology


Some of the most common physiological and morphological characteristics of these bacteria are as follows-

  • They are rod-shaped.
  • They are non-motile.
  • They are non-spore-forming. 
  • These bacteria are facultative anaerobes; they can respire even in the absence of oxygen.
  • They are catalase-negative; they do not use oxygen molecules as the terminal electron acceptor during respiration.
  • They occur singly or in pairs when cultured.
  • They form round or oval-shaped colonies with irregular edges. Colonies are umbonate; a protrusion is present along the edges of the colony.
  • They are Gram-positive in nature; their cell membranes are composed of a thick peptidoglycan outer layer without the presence of a lipid membrane.
Lactobacillus rhamnosus
SEM image of a species of Lactobacillus.

Lactobacillus helsingborgenesis: An introduction


Lactobacillus helsingborgenesis is a novel bacterial strain isolated from the stomach of the honeybee, Apis mellifera. This bacterial strain was isolated and identified using phylogenetic study techniques such as 16s RNA sequence analysis. The phenotypic and genotypic characteristics of this novel bacterial strain support its placement in the genus Lactobacillus.

Physiological and morphological features


The physiology and morphology of this species of Lactobacillus are more or less similar to other Lactobacillus species. These characteristics are as follows-

  • They are Gram-positive in nature.
  • They are non-motile.
  • They are non-spore-forming bacteria.
  • They occur singly or in pairs when cultured.
  • They are facultatively anaerobic and produce lactic acid as a product of glucose fermentation.
  • They are catalase-negative, rod-shaped bacteria.

Colony characteristics


After isolation, this novel bacterial strain was grown on an MRS agar medium at room temperature. The incubation period is 72 hours and the growth of the colonies was optimized via the addition of nutrients and amino acids such as fructose and cysteine respectively. Colonies grow optimally at pH 3.0 and are found to be highly acid-resistant. 

Some of the important features of the cultured colonies are as follows-

  • Colony size ranged from 2-3 mm in diameter.
  • Colonies were observed to be white and opaque.
  • Colonies were raised in profile and punctiform in shape.
  • Colonies were moist with a rough texture.
  • All colonies were circular with regular edges.

Apis mellifera


The novel bacterial species, Lactobacillus helsingborgenesis, was isolated from the honey stomach of the honeybee, Apis mellifera. This bee species, also commonly known as the western honeybee, is the most common bee species in the world. This species was the first-ever insect to be domesticated. These bees are typically utilized for their honey-production and pollinating abilities. They are present everywhere, except Antarctica.

These bees, like most honeybees, are eusocial. Eusocial insects form a complex social organisation which involves generational overlapping, brood care which is cooperative in nature and constant communication in order to coordinate common functions of the hive. These bees are known to communicate through hormones called pheromones and also through bee signs or “dances”.

 Honey Bees
Apis mellifera

Honey produced by these bees possesses antibacterial activity against Staphylococcus species. This honey is also known for its inability to rot. Over time, the honey just crystallizes, allowing its preservation for thousands of years. Honeybees collect honey from floral sources in second stomachs, also called honey stomachs. It is from this honey stomach that Lactobacilli were isolated and identified. It has been postulated that these Lactobacilli play a role in the preservation of honey within the honey stomachs of honeybees.


Lactobacillus helsingborgenesis is a rod-shaped, Gram-positive, non-spore-forming bacterial species that was recently isolated from the honey stomach of the honeybee species Apis mellifera. This novel bacterial species were isolated along with five other Lactobacillus bacteria. This bacterial strain grows optimally on supplemented MRS agar media at pH 3.0 and room temperature.

Tags: Microbes

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