Pseudomonas glathei

Pseudomonas glathei (Caballeronia glathei): A Reference Article on Its Identity, Taxonomy, Supplement Use, and Evidence Base

Important Preliminary Note

Pseudomonas glathei is not a botanical herb, plant extract, or classical dietary supplement ingredient in the conventional sense. It is a soil bacterium that has been included as one component among dozens of microorganisms in certain commercial soil-based organism (SBO) probiotic preparations sold as dietary supplements. No peer-reviewed clinical evidence exists that evaluates Pseudomonas glathei in isolation as a supplement ingredient; all human clinical data derive from studies of multi-strain SBO blends in which it appears as a listed constituent. This article presents all verifiable, source-backed facts about the organism's identity, reclassification history, its context within SBO products, and the evidence for those products, while clearly delineating what is and is not known about this specific organism's role in any observed effects.

1. Identity, Nomenclature, and Taxonomic History

1.1 Original Description and Classification

Pseudomonas glathei (Zolg and Ottow, 1975) is a Gram-negative soil bacterium first described in the mid-1970s and originally assigned to the genus Pseudomonas. Caballeronia glathei — the organism's currently accepted name — is a Gram-negative soil bacterium that is motile by means of one polar flagellum. Its original epithet glathei persists through multiple reclassification events as the species descriptor.

1.2 Reclassification from Pseudomonas to Burkholderia to Caballeronia

Advances in molecular taxonomy have resulted in the organism being moved out of the genus Pseudomonas on two separate occasions. 16S rRNA sequence analysis has redefined the taxonomy of many bacterial species; as a result, the genus Pseudomonas includes strains formerly classified in Chryseomonas and Flavimonas, while other strains previously classified in Pseudomonas are now classified in the genera Burkholderia and Ralstonia.

The first reclassification of P. glathei specifically occurred in 1998. In a survey of soil and wheat or maize rhizoplane bacteria, a large proportion of Burkholderia-like bacteria were found; among them, a homogeneous group of strains was identifiable based on phenotypic properties, fatty acid composition, DNA-DNA hybridizations, and 16S rDNA sequences. According to molecular data, the closest 16S rDNA phylogenetic neighbours were Burkholderia caryophylli and two previously named Pseudomonas species that clearly appeared to be part of the Burkholderia genus and were thus renamed Burkholderia glathei comb. nov. and Burkholderia phenazinium comb. nov.

The organism was subsequently reclassified again under the genus Caballeronia in 2016. The currently correct name is Caballeronia glathei (Zolg and Ottow 1975) Dobritsa and Samadpour 2016; Burkholderia glathei remains the correct name if this species is regarded within a separate genus Burkholderia.

This means that when dietary supplement labels or scientific literature from before 2016 refer to Pseudomonas glathei, they are using an outdated synonym for what is taxonomically now Caballeronia glathei. The organism has never belonged to the genus Pseudomonas sensu stricto as currently circumscribed in molecular taxonomy.

1.3 Broader Genus Context

The term "Pseudomonad" is derived from the Greek words pseudo (= false) and monad (= a single unit); the earliest classification of pseudomonads was based on cultural characteristics such as rod shape, Gram-negative reaction, and motility by means of polar flagella. Members of the previously described Pseudomonas are now classified into ten genera: Pseudomonas, Xanthomonas, Stenotrophomonas, Burkholderia, Gluconobacter, Ralstonia, Comamonas, Brevundimonas, Sphingomonas, and Caulobacter. P. glathei/C. glathei belongs to what researchers have termed the Burkholderia glathei clade (BGC), a grouping of related environmental bacteria. Partial gyrB gene sequence analysis of isolates from human and environmental sources identified 13 clusters as BGC bacteria; whole-genome sequence analysis, G+C content, fatty acid analysis, and biochemical characterization showed these represented novel Burkholderia species. BGC strains exhibited a broad metabolic versatility and developed beneficial, symbiotic, and pathogenic interactions with different hosts.

1.4 Biological Characteristics

The Burkholderia genus (to which this organism formerly belonged) includes non-spore-forming Gram-negative bacilli that, depending on the species, use one or several polar flagella for motility; individuals have a G+C ratio between 59 and 69.5%, are aerobic, oxidase and catalase positive, mesophilic, and synthesize polyhydroxybutyrate as reserve material. Most species in this clade have been isolated from bulk and rhizosphere soil, but also from contaminated soil and sludge from wastewater treatment systems.

2. Natural Source and Ecological Niche

Species in the Burkholderia glathei clade have been isolated from bulk and rhizosphere soil, as well as from contaminated soil and sludge from wastewater treatment systems. Two BGC species have been associated with less-studied hosts like fungi (Burkholderia sordidicola) and mosses (Burkholderia grimmiae), and numerous, mostly uncultivated BGC species have adopted endosymbiotic lifestyles in insect guts.

As a soil-dwelling organism, C. glathei (formerly P. glathei) is characteristic of what supplement manufacturers and some researchers call "soil-based organisms" (SBOs) — microbes naturally present in soil with which humans and other animals have had direct exposure historically through contact with unsterilized earth, root vegetables, and natural water sources. The term soil-based organism (SBO) encompasses over 100 highly diverse species of bacteria and other life forms naturally found in soil; before the introduction of industrialization and modern farming, humans had regular, daily contact with these bacteria.

3. Common Forms and Preparations as a Supplement Ingredient

Pseudomonas glathei is not sold as a standalone supplement ingredient and has not been subject to individual clinical testing. It appears exclusively as one constituent in multi-strain SBO probiotic blends. The most documented example is the commercial product Prescript-Assist™ (manufactured by Safer Medical, Inc., Fort Benton, Montana), in which it is listed alongside 27 other microorganisms.

Each 600 mg capsule of Prescript-Assist® contains a proprietary blend of Leonardite and 65 million of the following soil-based bacteria: Arthrobacter agilis, Arthrobacter citreus, Arthrobacter globiformis, Arthrobacter luteus, Arthrobacter simplex, Acinetobacter calcoaceticus, Azotobacter chroococcum, Azotobacter paspali, Azospirillum brasiliense, Azospirillum lipoferum, Bacillus brevis, Bacillus marcerans, Bacillus pumilus, Bacillus polymyxa, Bacillus subtilis, Bacteroides lipolyticum, Bacteroides succinogenes, Brevibacterium lipolyticum, Brevibacterium stationis, Kurthia zopfii, Myrothecium verrucaria, Pseudomonas calcis, Pseudomonas denitrificans, Pseudomonas fluorescens, Pseudomonas glathei, Phanerochaete chrysosporium, Streptomyces fradiae, Streptomyces cellulosae, and Streptomyces griseoflavus.

Prescript-Assist® is described as a combination of 28 probiotic microflora "soil-based organisms" uniquely combined with a humic/fulvic acid prebiotic (Leonardite) that enhances SBO proliferation. The prebiotic carrier, Leonardite, is a soft waxy mineral form of oxidized lignite rich in humic and fulvic acids, intended to support the growth and activity of the accompanying bacterial strains.

Regarding viability and shelf stability: Prescript-Assist is proven shelf stable, with variations of less than 5% over two years from date of manufacture when stored at 98°F / 37°C. No refrigeration is required for this preparation.

4. Traditional and Historical Use

There is no documented traditional or ethnobotanical use of Pseudomonas glathei (or Caballeronia glathei) as a deliberately consumed medicinal or dietary substance in any culture or historical period. The organism was not identified as a distinct species until the work of Zolg and Ottow in 1975. Its incorporation into dietary supplements is therefore entirely a modern, late-20th- and early-21st-century phenomenon.

The broader concept of consuming soil-derived microbes, however, has historical roots in the observation that pre-industrial and traditional populations consumed root vegetables, spring water, and other soil-contacted foods, thereby ingesting diverse soil microorganisms as a routine part of diet. The term SBO encompasses over 100 highly diverse species naturally found in soil; before industrialization and modern farming, humans had regular, daily contact with these bacteria. Some supplement manufacturers invoke this history to frame SBO products as a restoration of what they describe as ancestral microbial exposure patterns. This framing is a marketing concept and has no established historical documentation of deliberate therapeutic preparation or use of P. glathei specifically.

5. Key Constituents, Biological Properties, and Proposed Mechanisms of Action

Because Pseudomonas glathei/Caballeronia glathei has not been studied in isolation in the context of supplementation, no identified active metabolites or confirmed mechanisms of action in humans can be attributed to this organism specifically. What follows reflects the known biology of the organism and proposed mechanisms for SBO mixtures of which it is a component.

5.1 Metabolic Versatility

BGC isolates, the group to which B./C. glathei belongs, represent organisms distinguishable by genotypic and phenotypic characteristics and exhibit broad metabolic versatility, developing beneficial, symbiotic, and pathogenic interactions with different hosts. Within soil ecosystems, species related to C. glathei have been shown to degrade organic compounds and play roles in nutrient cycling.

5.2 Proposed Mechanisms in SBO Supplement Context

SBO supplement manufacturers and some researchers have proposed several theoretical mechanisms through which soil-derived bacteria in multi-strain products might exert effects in the gastrointestinal tract. These include competitive exclusion of pathogenic organisms, modulation of GI immune signaling, enhancement of intestinal barrier integrity, and production of short-chain fatty acids and other metabolites that influence the gut environment. However, none of these mechanisms have been specifically attributed to P. glathei in the peer-reviewed literature. There is much debate about the safety of SBOs; advocates claim that they normalize bowel function, aid in digestion, beneficially stimulate the immune system, and help re-seed the gut microbiota, and also praise SBOs for their ability to resist stomach acid and the lack of need for refrigeration.

6. Scientific Evidence by Area of Use

All clinical evidence reviewed here pertains to multi-strain SBO products containing P. glathei as one component among approximately 28 organisms. No study has isolated the contribution of P. glathei from the blend. Evidence strength is characterized as preliminary and of limited generalizability.

6.1 Irritable Bowel Syndrome (IBS)

Study 1 (2005 RCT): The symptomatic efficacy of Prescript-Assist, a treatment combining probiotic and prebiotic components, was evaluated to compare its effects with placebo in patients with a diagnosis of IBS, with a secondary goal of determining the nature of symptom clusters characterizing IBS. This was a double-blind, placebo-controlled clinical study in which patients were randomly assigned to receive either Prescript-Assist one 500-mg capsule BID or 1 placebo capsule BID for 2 weeks. The study identified 3 subsyndromic factors of IBS — general ill feelings/nausea, indigestion/flatulence, and colitis — and combined probiotic-prebiotic treatment with Prescript-Assist was associated with significant reductions in these factors. This study was published in Clinical Therapeutics (2005, Vol. 27, No. 6, pp. 755–761) and is indexed on PubMed (PMID 16117982).

Study 2 (2007 Open-Label Extension): The aim of the second study was to extend the previous 2-week assessment of the probiotic-prebiotic complex in patients with IBS; in this open-label, partially controlled, 1-year (approximately 14 months) extension study, data were collected from patients with IBS who continued treatment following the 2-week study, at 2 weeks and approximately 60 weeks after the end of the original study, with a total of 25 patients entering the 2-week extension and 22 completing the approximately 60-week follow-up. Results in the control group 2 weeks after crossover to treatment were similar to those from the original study, with reductions in IBS subsyndromes including general ill feelings/nausea (P < 0.001) and indigestion/flatulence (P < 0.001). This follow-up study was published in Clinical Therapeutics (2007, Vol. 29, No. 6, pp. 1153–1160).

Limitations of the IBS evidence: Both studies were conducted by researchers at Battelle Seattle Research Center and funded by the product manufacturer. The 2005 RCT covered only a 2-week treatment period, which is brief for assessing a gastrointestinal condition. The 2007 study was open-label and only partially controlled. Neither study was independently replicated. Critically, it is suggested that probiotic use may be associated with improvement in IBS symptoms compared to placebo, but these results should be interpreted with caution given the methodological limitations of contributing studies. Furthermore, there is a lack of assessment and systematic reporting of adverse events in probiotic intervention studies, and interventions are poorly documented, leaving the current literature not well equipped to answer questions on the safety of probiotic interventions with confidence.

6.2 Bacterial Diarrhea

A third published study (Bittner, Caicedo, De la Torre, and Yokelson, 2006) evaluated Prescript-Assist for bacterial diarrhea in human communities in Ecuador. Clinical research was conducted to evaluate the efficacy of Prescript-Assist, which had previously demonstrated efficacy against canine bacterial diarrhea in short-term studies and against IBS-related gastric diseases in both short-term and longer-term human studies; in this study, Prescript-Assist treatment was shown to result in significantly shorter diarrhea durations than standard antibiotics used in treating bacterial diarrhea (χ² (4) = 41.1, P < 2.6 × 10⁻⁷).

Limitations: This study also originated from the same research group that conducted the IBS trials and was not conducted under fully controlled conditions. Independent replication has not been reported in the peer-reviewed literature.

6.3 Evidence Summary

In aggregate, the clinical evidence for the multi-strain SBO product containing P. glathei amounts to: two small, industry-associated human clinical studies in IBS (one 2-week RCT, one 1-year open-label extension), one field study in bacterial diarrhea, and earlier open-label reports. Prescript-Assist and other advanced probiotic-prebiotic combinations have been described as having "considerable promise as emerging treatments for a wide spectrum of both acute and chronic GI diseases," but this characterization comes from the same research group. No independent Cochrane review or systematic review has specifically examined Prescript-Assist or any SBO product containing P. glathei. The evidence base is preliminary, of limited independence, and insufficient to attribute any observed effects to P. glathei specifically.

7. Body Systems and Health Areas of Association

Given its inclusion in a gastrointestinal supplement preparation, P. glathei has been associated — only as part of a blend — with the following systems:

• Gastrointestinal system: The multi-strain SBO blend of which it is a part has been studied for IBS symptom relief (nausea, flatulence, indigestion, colitis-like symptoms) and for reduction of bacterial diarrhea duration.
• Gut microbiome: SBO products are marketed on the theoretical basis of restoring gut microbial diversity, but no evidence specifically links P. glathei to measurable microbiome changes in humans.

No peer-reviewed evidence links Pseudomonas glathei/Caballeronia glathei to immune, neurological, cardiovascular, or metabolic outcomes in humans.

8. Dosage Forms and Reported Dosages

Dosage information available in the scientific literature refers exclusively to the multi-strain Prescript-Assist product; no dose-finding studies or pharmacokinetic data exist for P. glathei in isolation.

• Clinical trial dosage: Patients were randomly assigned to receive Prescript-Assist at one 500-mg capsule BID (twice daily) for 2 weeks.
• Commercial preparation: Each 600 mg capsule contains 65 million total organisms from the 29-strain proprietary blend, in which P. glathei is one of four listed Pseudomonas-type organisms.
• No published source provides the per-organism cell count of P. glathei specifically within the blend.

9. Safety Considerations

9.1 Regulatory Risk Classification of the Organism

Despite historically being placed in the Pseudomonas genus, C. glathei (formerly P. glathei, then B. glathei) has a defined regulatory safety classification. The risk group for Canada classifies this organism as risk group 1, with the note: "Animal classification RG: 1 — Security sensitive biological agent: No — Terrestrial animal pathogen under Canadian Food Inspection Agency authority: No — Containment level: Containment Level 1." Risk group 1 denotes organisms that are unlikely to cause human or animal disease.

This classification must be distinguished from the situation of related members of the Burkholderia genus. Pathogenic strains such as B. pseudomallei and B. mallei can cause serious disease in mammals, while other Burkholderia strains are opportunistic pathogens infecting humans or animals with a compromised immune system. Caballeronia glathei is not in the same pathogenic clade as B. pseudomallei or members of the B. cepacia complex.

9.2 Distinction from Pathogenic Pseudomonas and Burkholderia Species

Consumer and clinical concerns about Pseudomonas in supplements generally relate to Pseudomonas aeruginosa, which is a very different organism. Pseudomonas is a strictly aerobic, Gram-negative bacterium of relatively low virulence in most contexts; the organism is ubiquitous, with a predilection for moist environments, primarily as waterborne and soilborne organisms. Pseudomonas aeruginosa is a clinically significant opportunistic pathogen that often causes nosocomial infections; these organisms exhibit innate resistance to many antibiotics and can develop new resistance after antimicrobial exposure. P. glathei/C. glathei is not P. aeruginosa and is not in the Pseudomonas sensu stricto group. Various species of Pseudomonas exist; while some can cause disease in humans, other strains are a normal part of healthy soil and are not considered pathogenic.

Similarly, while Burkholderia cepacia has emerged as a human pathogen causing numerous outbreaks, particularly among cystic fibrosis patients, Caballeronia glathei is not a member of the B. cepacia complex and is not implicated in CF-related lung disease.

9.3 Concerns for Immunocompromised Individuals

Although some opportunistic Burkholderia pathogens are known to promote plant growth and fix nitrogen, the risk of infection to infants, the elderly, and immunocompromised people has not only resulted in restriction on use but has also limited the application of non-pathogenic, symbiotic species. Reflecting this broader concern, several commentators note that soil-based organisms should be avoided completely if a person is critically ill or immunocompromised, as we still do not have a good understanding of how these organisms act in vulnerable populations, and there have been case reports of adverse effects in those without sufficient immune function.

9.4 General SBO Safety Profile and Adverse Events

While short-term studies are promising, research on prolonged use is limited; a 2024 scoping review on soil microbiota and gut health noted that we do not fully understand how continuous supplementation affects the gut microbiome's balance. There is a lack of assessment and systematic reporting of adverse events in probiotic intervention studies, and the current literature is not well equipped to answer questions on the safety of probiotic interventions with confidence.

The only clinical trial data for the specific multi-strain product containing P. glathei did not report significant adverse events in the studied populations. Mild and transient gastrointestinal symptoms (bloating, gas, loose stool) during initial use have been reported anecdotally and are consistent with the general profile of multi-organism probiotic products.

9.5 Regulatory Status

In the United States, Prescript-Assist and similar SBO products are sold as dietary supplements. Probiotics are not well regulated by the Food and Drug Administration (FDA), so product quality depends on manufacturer adherence to good manufacturing practices (GMP) certification. No authorized health claim has been issued by the FDA, EFSA, or any comparable regulatory authority specifically for Pseudomonas glathei/Caballeronia glathei or for any multi-strain SBO product. There are no WHO monographs, ESCOP monographs, German Commission E monographs, or USP entries for this organism.

10. Summary of Evidence and Limitations

Pseudomonas glathei — now correctly identified as Caballeronia glathei — is a taxonomically reclassified soil bacterium with a Canadian regulatory risk group 1 designation, meaning it is not regarded as a human or animal pathogen under current classification. Its presence in dietary supplements is confined to its role as one of approximately 29 organisms in a specific multi-strain SBO probiotic blend (Prescript-Assist™). Two peer-reviewed clinical studies (2005 RCT and 2007 open-label extension), both by the same research group and examining the full multi-strain blend rather than any individual organism, provide limited, preliminary evidence of benefit in IBS symptom reduction. A third study reported shortened diarrhea duration versus standard antibiotics in a community setting. No mechanistic, pharmacokinetic, toxicological, or isolate-specific clinical data for P. glathei exist in the peer-reviewed literature. The evidence is insufficient to draw conclusions about the contribution — if any — of this individual organism to any observed clinical effects.

References

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