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Probiotic nasal spray for sinusitis: How Lactobacillus bacteria can help

The strain of bacteria that got adapted to life inside our noses would aid in the prevention of the chronic, painful inflammation of sinusitis. The discovery led to the development of the probiotic nasal spray to treat this condition.

“Friendly bacteria” from the genus Lactobacillus are primarily known for having beneficial effects on the genital tract, gut, and skin, where they would be safeguarded against any form of infection modifying the immune responses.

An Overview of Lactobacilli Bacteria and Their Benefits

Lactobacilli are bacteria in the shape of a rod that can ferment sugar-producing lactic acid as their byproduct, inhibiting other microorganisms’ growth. It is the kind of bacteria that prefers to grow in conditions with little to no oxygen.

However, a bit is known about the potential benefits of Lactobacilli living inside our noses. These are so considered sinusitis, and they are extremely painful, resulting in swelling of the nasal cavity or the sinuses. One out of eight individuals in the US is affected by it. (1)

The live microorganisms that aid in the enhancement of gut health are the probiotics, (2) and there are a couple of studies that throw light that these would help treat sinusitis.

What Is Sinusitis & Its Symptoms?

Sinusitis is mainly the inflammation of the sinus lining, in simpler terms. Whenever these symptoms take place occasionally and last over a shorter while, they are coined as acute sinusitis. If symptoms last for several weeks, they are referred to as chronic sinusitis, CRS, or Chronic Rhinosinusitis. The following are a couple of common symptoms of this issue:

Healthy Strains of Lactobacillus Bacteria for Sinusitis Prevention and Treatment

The professor made several studies of applied biotechnology and microbiology along with a team by comparing nasal bacteria from 100 healthy individuals and samples from 225 people suffering from chronic sinusitis.

The researchers discovered that healthier people had around 10 times greater Lactobacilli around a few areas of the nose using the sensitive genetic sequential methods. The team then identified the bacterial strains found in the healthier subjects.

Ruling out any of this would have originated out of the commercial probiotics or fermented foods where the scientists had searched for bacteria with the structural and genetic adaptations to life present in the nose.

L. casei AMBR2 is one such substrain appearing specifically well-adapted. The casei strain of the Lactobacillus had recently offered their group term Lacticaseibacillus (3) due to their unique characteristics, like being able to reside in environments with rich amounts of oxygen.

Numerous Lactobacilli prefer to grow in areas such as the gut, where there is huge oxygen deprivation and further risks associated with oxidative wear and tear. But, L. casei AMBR2 comprises a distinctive, unique genetic profile allowing the bacteria to survive at the higher oxygen levels in the nose.

The researchers noticed that it is the kind of bacteria covered through the flexible, hair-like tubes known as fimbriae which they consider would allow the bacteria to stick right at the inner surface or even the epithelium area of the nose.

The team developed L. casei AMBR2 in the lab with the epithelial cells from the upper respiratory tract coming together with specific pathogens commonly infecting this area of the body. They discovered that the bacteria reduced the swollen cell’s responses and inhibited the growth of pathogens.

The Primary Triggers of Sinusitis and How to Stop Them

It is important to identify the real cause of the infection to aid in stopping fatigue, pain, congestion, and other sinus infection-based symptoms. Whenever it arrives at being the trigger behind sinusitis, there are generally two views:

  • The Conventional Medicinal View

    When harmful bacteria invade, sinuses happen as they are sterile environments, although modern research does not approve of the idea. In this instance, the doctors would prescribe antibiotics to destroy these bacteria like Haemophilus Influenza, Staphylococcus aureus, and Pseudomonas aeruginosa.

    Healthcare professionals often assume that the issues are related to the patient’s immune system and prescribe additional antibiotics whenever sinus infections reoccur.

    Sadly, with time, bacteria will become resistant to the antibiotics, (4) and there is a greater dosage that differs from the antibiotics required for repeatedly treating similar symptoms. The cycle would lead to the imbalances of the normal bacteria in our sinuses, increasing the likelihood of sinusitis that gets triggered only by a common cold or even sore throat.

    Additionally, doctors often recommend sinus operations after it appears as the antibiotics will no longer work effectively for treating these infections.

  • The Modern Medicinal View

    The latest cutting-edge technology and groundbreaking studies like genetic sequencing have shown that sinusitis results from the imbalanced sinus microbiome or microbial community treated with the proper probiotic like Lactobacillus sakei. Numerous bacteria, virus species, and fungi make up this microbial community.

    The most astonishing discovery is that healthier people have communities of microbes, including both harmful and beneficial microbes living happily together throughout the entire body. The issues would start arising whenever the sinus microbiome faces imbalances, and pathogenic bacteria overpower the beneficial bacteria, leading to further sinus infections.

Other Factors Leading To Sinusitis

Viral infections include sore throat, environmental toxins like air pollution, cigarette smoke, higher mold levels, formaldehyde, allergies, pathogenic biofilms, (5) nasal polyps, a devastated nasal septum, and immune system diseases would trigger sinuses, (6) and further leading to chronic sinusitis. Therefore, sinus infections get triggered through almost anything, making the nasal passages inflamed and swollen.

Role of Probiotics

The WHO defines probiotics as products that contain living microorganisms that, when administered in the correct quantity, benefit the host’s health. [7]

Probiotics are generally defined by Who as products comprising living microorganisms whenever administered in the right quantity that would benefit the host’s health. (7)

Never get confused between probiotics and prebiotics. Prebiotics are mainly derived from foods that are not digested, and the beneficial effect on the host contributes to the activity, growth, and bacteria.

Some products contain prebiotics, and the probiotics are referred to as symbiotics. (8) The entire mechanism of the action of the probiotics is described primarily within the gastrointestinal system, including various strategies through which they inhibit the pathogenic microorganisms’ actions.

The probiotics would induce the inhibition of the adhesion of the pathogens to the mucous membranes with the stabilization of the tighter junctions within the epithelial layer with the reduced permeability of the mucosa, which is the competitive inhibition of the pathogens, production of varied substances toxic to the pathogenic microorganisms (9) and modulation of the immune system.

The action of the probiotics to restore the epithelial barrier through the modulation of rigid junctions and adherence junctions affects their role in modulating the host’s immune response through interactions with the dendritic cells. It would help promote the downregulates T-helper 1 and T-helper 2 and T-cells or the (Tregs).

The studies have noted that the ability to adhere to the nasal epithelium, which is the ability to survive in aerobic conditions and at lower temperatures, should be addressed. (10) These are the requisite conditions for the probiotics to compete with opportunistic bacteria like Staphylococcus aureus.

Nasal Probiotic Sprays for Treating the Sinus Microbiome

Lastly, the team developed the probiotic nasal sprays comprising bacteria to check whether they would colonize the nose. It is essential since the nose gets adapted to filter out the foreign airborne elements, mainly clearing in less than 15 minutes.

Essentially, the researchers had initially checked regarding the strain as not being resistant to the antibiotics used commonly.

In a study, around twenty healthy volunteers used the spray twice each day for almost two weeks, and the outcome was a successful colonization of their nose through bacteria. They had experienced no side effects, and the bacteria existed even a couple of weeks later.

The other step is to explore the strain’s anti-inflammatory properties and identify other antimicrobial molecules produced along with the lactic acid. The proof-of-concept studies show that it is possible and safer to introduce L. casei AMBR2 into the microbiome of these healthier volunteers.

The team’s ultimate goal is to develop and clinically test the probiotic treatment for chronic sinusitis, as the patients would lack treatment options. However, existing treatments would lead to adverse effects, and those on antibiotics would develop resistance due to nasal bacteria.

It is thought that a few specific patients benefit by remodeling their microbiome while introducing beneficial bacteria within the nose to reduce specific symptoms. However, it is a long way to head with clinical and mechanistic studies.

Choosing the Probiotic

There is a greater possibility to use probiotics as a successful treatment for sinusitis, exciting the researchers (11) who mainly focus on the Lactobacillus bacteria helping to enhance the sinus microbiome and reducing the number of pathogenic bacteria bringing better balance to the microbiome.

A couple of promising studies have already suggested that transplanting the whole microbial community through the healthier donor into the nasal passages of the patients would contribute to the treatment of chronic sinus infections; however, this method prevails in the future.

There are other probiotic Lactobacillus species under the microscope; however, they generally did not produce positive outcomes and have helped only a couple of people with sinus infections.

Final Notes

Using probiotics as a medical treatment for several health conditions and diseases is still under a lot of research. The recent developments and new research make things more exciting. Using probiotics to treat sinusitis is the ideal step toward understanding the sinus microbiome. The future of sinus health and healthcare had never been in the limelight.


  1. https://pubmed.ncbi.nlm.nih.gov/30582496/
  2. https://www.nature.com/articles/nrgastro.2014.66
  3. https://pubmed.ncbi.nlm.nih.gov/32293557/
  4. https://onlinelibrary.wiley.com/doi/abs/10.1002/lary.26232
  5. https://www.sciencedirect.com/science/article/pii/S209588111630004X
  6. https://www.worldallergy.org/education-and-programs/education/allergic-disease-resource-center/professionals/rhinosinusitis-global-overview
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8701913/#B8-healthcare-09-01715
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8701913/#B41-healthcare-09-01715
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8701913/#B42-healthcare-09-01715
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8701913/#B44-healthcare-09-01715
  11. https://stm.sciencemag.org/content/4/151/151ra124.short
Team PainAssist
Team PainAssist
Written, Edited or Reviewed By: Team PainAssist, Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:March 12, 2023

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