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Oral microbes Credit: Wikipedia

We all have millions of microbes living in our sinuses – bacteria, viruses, and fungi. This is normal.

An amazing fact is that living together are beneficial, benign, and what we normally consider harmful microbes. And this is normal. This rich and diverse community of microbes living in the sinuses is called the sinus microbiome or microbiota.

OUR SINUSES: We have 4 pairs of sinuses in our heads, which are air-filled and lined with a mucus membrane with cilia. The cilia steadily beat (700 to 800 times a minute!) in order to move mucous into the nasal cavity. Microbes live in the mucous lining.

For years it was thought that the sinuses were sterile, and a sinus infection meant that a harmful microbe (pathogen) had invaded. In the 1990s a popular view was that fungi were the cause of chronic sinusitis. But with the development of new technologies (genetic sequencing) in the last 2 decades, it was discovered that millions of all sorts of microbes live in the sinuses in both healthy and sick persons. And yes, that it was normal to have fungi in the sinuses (so that theory was dropped).

THE CURRENT VIEW: Millions of microbes live in complex communities, interact with one another, and with us (we’re their host!). In healthy persons all the microbial species are in equilibrium, and potentially harmful species are kept in check. But sometimes the communities can become disrupted and imbalanced – this is called dysbiosis.

When there is disruption (e.g., from an infection, allergies), then there can be an overgrowth or a big increase in the potentially harmful microbes living in the sinuses. This can make you more susceptible to an infection or it can result in sinusitis symptoms. (In chronic sinusitis there is an imbalanced sinus microbiome and also inflammation of the sinus mucous lining.)

Staphylococcus Credit: Wikipedia

A HEALTHY SINUS MICROBIOME: It turns out that what is a healthy sinus microbiome varies from person to person. Yes, there is a “core” sinus microbiome of species that are shared throughout the world. (For example: Corynebacterium and Staphylococcus species) ...continue reading "Microbes Live In Our Sinuses"

Everyone has millions of microbes living in complex communities in their sinuses. All these hundreds of species of bacteria, fungi, and viruses are the sinus microbiome or sinus microbiota. In addition, some (many?) people also have tiny organisms called archaea living in their sinuses.

What are archaea? Archaea are single-celled organisms that lack cell nuclei, and have a unique cell wall membrane. Very little is known about them, what their role is in the sinuses (that is, what are they doing there?), how do they interact with the host (the person), and whether their presence is beneficial or not.

There are only a few studies looking at archaea in humans, and while very little is known, the current view is that there are no known harmful archaea ("archaeal pathogens or parasites").

In a 2019 study, French researchers found archaea in the sinuses of 9 of their patients with chronic sinusitis - and therefore thought they were linked to disease. But unfortunately they didn't look to see if archaea are also found in the sinuses of healthy persons, thus there wasn't a comparison group. They found methanogenic archaea (the only microorganisms able to produce methane) in these nine patients, and they thought that the archaea were contributing to or causing the chronic sinusitis.

The Methanobrevibacter species they found were  M. smithii, M. oralis, and M. massiliense, of which 2 have been found in dental plaque and periodontitis lesions, and one is a gut methanogen. [Note: This means it is found in the gut and is methane producing - but that doesn't mean it is harmful.]

Finally, a more recent and comprehensive study looked at archaea and bacteria in the sinuses of both healthy persons and those with chronic sinusitis. University of Auckland researchers found that only 6 out of 70 persons (both healthy and with sinusitis) had archaea in the sinuses, and they were very low in numbers and in diversity. In those with archaea, there was a lot of variation between people. They did not see any archaea associated with chronic sinusitis.

Archaea found were from Euryarchaeota, Thaumarchaeota, and Methanobrevibacteriaceae phyla.

One can only wonder what the archaea are doing in the sinuses in those with them. Especially, as the researchers point out that archaea are characterized by a unique cell wall membrane that "assists survival in extreme conditions such as hydrothermal vents, salt lakes, anoxic and highly acidic or alkaline environments". Also, that recent studies suggest that the human immune system recognizes and can be "activated" by archaea.

Archaea. Credit: Wikipedia

Finally, studies also mention that archaea are resistant to many antibiotics (because of lack of peptidoglycan in their cell wall). It is unknown how this influences their role (if any) in human health and disease.

As you can see, much is unknown right now. Even how many people have archaea in their sinuses, and what kinds of archaea. Stay tuned.

Article by B.W. Mackenzie et al in Frontiers in Cellular Infection and Microbiology: A Novel Description of the Human Sinus Archaeome During Health and Chronic Rhinosinusitis

Once again a study looked at biofilms in sinuses - but this time in the sinuses of healthy people and not those with sinusitis. Various different species of bacteria and small size "microcolonies" or biofilms were found in the healthy maxillary sinuses of all 30 people - so yes, it appears that the presence of biofilms in the sinuses is normal in healthy people. And yes, the presence of bacteria (even some low levels of species which are typically associated with sinusitis) are normally found in the sinuses of healthy people.  (Earlier research also found this last finding.)

The researchers state that it is normal for people to have "small size bacterial microcolonies" (of different kinds of bacteria) in the sinuses. The researchers theorized that the biofilms are probably "in equilibrium" under the influence of  "inhibiting defensive factors of the body", but they can become a source of infection if there are favorable conditions (such as illness). In other words, the researchers said that these biofilms are more like "bacteria films" in that they contain bacteria, but they live in small colonies that don't cause an inflammatory response with sinusitis symptoms.

One negative of this study was that advanced genetic sequencing was not done on the samples. Instead all samples taken from the people were cultured, which we now know misses a lot of bacterial and other microbial species (fungi, viruses). They looked at the microcolonies (biofilms) with scanning microscopes. Thus, while they found an assortment of bacteria on the sinuses of each person - they only found a total of 41 bacterial species among 30 persons. This is in contrast to studies using modern genetic sequencing that found hundreds of microbial species in healthy sinus microbiomes (microbial communities).

The other issue is that it is not clear to me if there were biofilms or  microcolonies that contained "beneficial" species in any of the samples. Other research suggests that biofilms of beneficial bacteria are also found in humans, and that this is one way beneficial bacteria that normally can't survive with exposure to oxygen can survive oxygen (the slime coating on the colony protects the bacteria within).

Other studies also stress that in healthy people there is "homeostasis" or "equilibrium" among all the microbes living in the sinuses, - a microbial community (which includes biofilms), and which helps maintain sinus health. See post with discussion of Mackenzie et al 2017 study: "A stable network of microbial interactions, established through processes such as niche competition, nutrient cycling, immune evasion, and biofilm formation help maintain homeostasis during health." But, as has been usual in recent sinus research, the current study also stated that much is unknown, that there are theories which are not yet proven one way or another, and more research needs to be done. Of course.... Excerpts from Morawska-Kochman et al research article in PLoS ONE:

The presence of bacterial microcolonies on the maxillary sinus ciliary epithelium in healthy young individuals

The aim of this cross-sectional in vitro study was to evaluate the mucosal surfaces of healthy maxillary sinuses, explore different forms of bacterial microorganism colonies present on the mucous membrane, and determine a mucosal surface area they occupy. Samples of the maxillary sinus mucosa were collected from 30 healthy patients (M = 11; F = 19). The material was obtained during the Le Fort I osteotomy performed during corrective jaw surgery. The morphological and morphometric analysis of sinus mucosa and bacterial film that was grown on it was performed using scanning electron microscopy (SEM) as well as imaging software.

Scanning electron microscopy analysis showed the presence of different bacterium and bacteria-like structures in all the analyzed samples. In most cases, the bacterial film was mostly composed of diplococci-like and streptococci-like structures on the mucosa of the paranasal sinus. In any case, the mucous layer did not cover the whole lining of the evaluated sample. Each colony consists of more than 20 single bacterial cells, which has grown in aggregates.

Under the conditions of normal homeostasis of the body, the maxillary sinuses present diverse bacterial colonization. The bacteria are dispersed or concentrated in single microcolonies of the biofilm on the border of the mucous covering the ciliary epithelium. There is no uniform layer of the biofilm covering the mucosa of the maxillary sinuses. Because the biofilm is detected on healthy individuals sinus mucosa, the clinical question if it may become pathogenic is unclear and require an explanation.

It should also be noted that pathogenic organisms, such as Pseudomonas aeruginosa, Haemophilus influenzae, Streptococcus pneumoniae, or Staphylococcus aureus can be found in patients without active symptoms of the disease. Usually, colonization is defined as the presence of bacteria on the mucous membrane, and the lack of the inflammatory response distinguishes it from an infection.

However, the bacteria film in contrast to typical biofilm might be defined by the presence of bacteria, that growth in colonies without inducing the inflammatory response. Thus, the aim of the study was to evaluate the mucosal surfaces of the healthy maxillary sinuses (without any history of recent acute sinus inflammations or chronic inflammation in the past), to identify different forms of bacterial microorganisms which could, under certain conditions, become opportunistic or pathogenic and determine a mucosal surface of the area they occupy.

Scanning electron microscope investigations revealed the presence of bacterial film on the surface of maxillary sinus mucosa in 30 patients. Moreover, microbiological examinations of specimens taken from study participants revealed the presence of various types of aerobic and anaerobic bacteria in 28 cases (93.34%) out of 30 studied samples. All samples had mixed flora. In total, 41 different microorganisms were isolated. The most frequently found microorganism was Streptococcus spp. in over 90% of all samples, while Propionibacterium acnes were present in 29,2% of samples, and Staphylococcus spp. was present in 17% of the samples.

Scanning electron microscopy analysis showed that the mucous layer has a thickness of 200 nm (± 40), which is covered up to 5% of the surface of each sample. The analysis showed the presence of bacteria-like microcolony structures in all analyzed samples.....Each colony consisted of more than 20 single bacterial cells, that had grown in aggregates. These clearly indicate the existence of a bacterial-like microcolony on maxillary sinus mucosa.

Bacterial microcolonies on the maxillary sinus ciliary epithelium in healthy young individuals. Credit: Morawska-Kochman et al.

New research that found that microbial communities vary between the sinuses in a person with chronic sinusitis. This is a result that many sinusitis sufferers already suspect based on their sinusitis symptoms. The researchers also found that bacterial communities in the sinuses vary between people with chronic sinusitis. It is frustrating though for me to read study after study where the researchers focus on describing the types of bacteria found in chronic sinusitis sufferers (and then just saying that the sinus microbiomes or community of microbes vary from person to person) rather than studies comparing the sinus microbiomes (bacteria and other microbes, such as fungi) between healthy individuals and sinusitis sufferers.

Since research finds that sinusitis sufferers have altered sinus microbiomes, then what would be really helpful now is finding more beneficial or keystone species (besides Lactobacillus sakei) that are needed for healthy sinus microbiomes. This would be an important step towards then adding (perhaps using a nasal spray) these missing microbes to the sinus microbiome. From Frontiers in Microbiology:

Bacterial communities vary between sinuses in chronic rhinosinusitis patients

ABSTRACT: Chronic rhinosinusitis (CRS) is a common and potentially debilitating disease characterized by inflammation of the sinus mucosa for longer than 12 weeks. Bacterial colonization of the sinuses and its role in the pathogenesis of this disease is an ongoing area of research. Recent advances in culture-independent molecular techniques for bacterial identification have the potential to provide a more accurate and complete assessment of the sinus microbiome, however there is little concordance in results between studies, possibly due to differences in the sampling location and techniques. This study aimed to determine whether the microbial communities from one sinus could be considered representative of all sinuses, and examine differences between two commonly used methods for sample collection, swabs and tissue biopsies. High-throughput DNA sequencing of the bacterial 16S rRNA gene was applied to both swab and tissue samples from multiple sinuses of 19 patients undergoing surgery for treatment of CRS. Results from swabs and tissue biopsies showed a high degree of similarity, indicating that swabbing is sufficient to recover the microbial community from the sinuses. Microbial communities from different sinuses within individual patients differed to varying degrees, demonstrating that it is possible for distinct microbiomes to exist simultaneously in different sinuses of the same patient. The sequencing results correlated well with culture-based pathogen identification conducted in parallel, although the culturing missed many species detected by sequencing. This finding has implications for future research into the sinus microbiome, which should take this heterogeneity into account by sampling patients from more than one sinus. It may also be of clinical importance, as determination of antibiotic sensitivities using culture of a swab from a single sinus could miss relevant pathogens that are localized to another sinus.

CRS can be a debilitating condition that is recalcitrant to treatment. Bacterial colonization of the sinuses is likely to play an important role in the pathogenesis and perpetuation of the disease; however different studies have yielded contrasting results with respect to which bacterial taxa are characteristic of the disease (ref). We observed bacterial communities dominated by different taxa in CRS patients; for example some have sinuses colonized primarily with Haemophilus, while others are dominated by Corynebacterium and Staphylococcus, or Pseudomonas. Some patients’ sinuses contain anaerobic bacteria such as Anaerococcus, Finegoldia, and Peptoniphilus, while these were absent from others. Indeed, our results have shown, for the first time, that it is possible for a patient to simultaneously have different bacterial communities in different sinuses, pointing to distinct, localized microbiomes within the same patient. Understanding this variation in the sinus microbiome could prove critical to the appropriate selection of treatments for CRS in the future.

The weighted unifrac distances between samples within patients (Figure 1) demonstrate that at least some CRS patients have substantial variation of bacterial communities between sinuses, although it is significantly smaller than the variation observed between different individuals. While this variation was related to abundance rather than the presence or absence of dominant community members, some of these variations were large: for example Corynebacterium sequences dominating the right sinuses of patient 003 (60.7 and 41.7% of all sequences), while the left sinuses had much smaller abundances (9.8 and 6.2%) and were dominated by the anaerobic bacteria Anaerococcus, Finegoldia  and Peptinophillus.


[UPDATE:  I added an Oct. 2018 update to the post The One Probiotic That Treats Sinusitis, which was originally posted in January 2015.]  Updates incorporate the latest information about treatments and products with Lactobacillus sakei  (kimchi brands, the probiotic Lacto Sinus , the sausage starter culture Bactoferm F-RM-52, etc.). According to research by Abreu et al (2012)Lactobacillus sakei is a bacteria or probiotic (beneficial bacteria) that chronic sinusitis sufferers lack and which treats chronic sinusitis. Chronic sinusitis sufferers also don't have the bacteria diversity in the sinuses that healthy people have.

Many thanks to those who have written to me about their experiences with L. sakei products and sinusitis treatment.  Please keep the updates, results, and progress reports coming. If you have had success with other kimchi brands, please let me know so that I can add it to the list. And I also want to hear if other probiotics work or don't work, or if you have found other sources of Lactobacillus sakei or new ways to use L. sakei. It all adds to the knowledge base which I will continue to update.  You can Comment after posts, the Sinus Treatment Summary page, on the CONTACT page, or write me privately (see CONTACT page).

It is now over 2 1/2 years since my family (4 people) successfully treated ourselves with Lactobacillu sakei for chronic sinusitis and acute sinusitis. We feel great! With each passing year we can tell that our sinus microbial community is bettter, and levels of inflammation are down. As a consequence, we are getting fewer colds or viruses than ever. And best of all - no antibiotics taken in over 2 1/2 years! Yes, Lactobacillus sakei absolutely works as a treatment for sinusitis.

[Read the updated post: The One Probiotic That Treats Sinusitis - with Oct. 2018 update]