Scientific Name(s): Bacillus clausii
Common Name(s): Enterogermina, Erceflora, Probiotic
Medically reviewed by Drugs.com. Last updated on Nov 30, 2022.
B. clausii is a commonly used Bacillus spp. probiotic. The antimicrobial and immunomodulatory properties of B. clausii support its use for the treatment and prevention of intestinal bacterial flora disorders, with particular efficacy suggested for diarrhea according to clinical trial data and a systematic review and meta-analysis. Small trials have investigated use for prevention of infection in preterm neonates; treatment of nasal allergies and upper respiratory infections in children; and treatment of acute or chronic diarrhea, small-intestine bacterial overgrowth (SIBO), and adverse effects of Helicobacter pylori therapy in adults. According to the World Gastroenterology Organization guidelines, data suggest that probiotics as adjuvant therapy may be helpful in H. pylori eradication (level 1b evidence), but data are insufficient to support probiotic monotherapy as an effective eradication strategy.
In clinical studies, typical dosing was 2x109 spores administered orally as a capsule or suspension 2 or 3 times daily, for 10 days up to 3 months.
Manufacturer product information: Adults: 4 to 6x109 spores/day (2 to 3 vials/day of suspension or 2 to 3 capsules/day). Children and infants: 2 to 4x109 spores/day. Use is recommended for short periods of time.
Hypersensitivity to B. clausii or to any of the product excipients.
According to the product information, B. clausii can be used during pregnancy and lactation and in breastfeeding infants.
None well documented.
No adverse effects were noted in clinical trials of B. clausii or in the product information.
Bacillus strains for animal nutritional use and for human use (pharmaceutical preparations) include Bacillus subtilis, Bacillus licheniformis, Bacillus coagulans, Bacillus toyoi (cereus), Bacillus natto (subtilis), B. clausii, Bacillus polyfermentans, and Bacillus cereus. B. clausii is a rod-shaped, nonpathogenic, spore-forming, aerobic, gram-positive bacterium that is able to survive transit through the acidic environment of the stomach and colonize the intestine even in the presence of antibiotics.(Ianiro 2018, Urdaci 2004)
Spore-forming Bacillus spp. have been used for decades in the form of fermentation products or spore-based probiotic supplements; however, only a few Bacillus strains are recognized as safe and are available for commercial use.(Ghelardi 2015, Upadrasta 2016) Clinically, B. clausii is one of the most commonly used microorganisms of the Bacillus spp.(Lopetuso 2016) Historically considered to be soil microorganisms, Bacillus spp. bacteria should be reconsidered as gut commensals because their prevalence in animal feces is now recognized to be greater than previously thought.(Ghelardi 2015)
Probiotic preparations have been used throughout history. In a Persian version of the Old Testament, Abraham's longevity was purported to be the result of drinking sour milk. In 76 BC, the Roman historian Plinius described fermented milk as a remedy for gastroenteritis. In 1916, experiments were conducted to implant Escherichia coli as a means of fighting pathogenic intestinal flora.(Schrezenmeir 2001)
In 1965, the term "probiotic" was first used to describe "substances secreted by one microorganism that stimulate the growth of another"—in other words, the opposite of an antibiotic.(Schrezenmeir 2001) Revised definitions have appeared in the literature to accommodate mechanisms of action and stimulation of systems other than bacteria. An all-encompassing definition has been proposed by one group: "A preparation of or a product containing viable, defined microorganisms in sufficient numbers, which alter the microflora (by implantation or colonization) in a compartment of the host and by that exert beneficial health effects in this host."(Schrezenmeir 2001) Related concepts of prebiotics and synbiotics have also been elaborated.(Elmer 2001, Schrezenmeir 2001) The study of microbes inhabiting the human GI tract and their effect on disease is an important part of the ongoing Human Microbiome Project of the US National Institutes of Health.(NIH 2020)
Uses and Pharmacology
Probiotics are intended to assist the body's natural gut microbiota.(WGO 2017) The potential mechanisms by which probiotics exert their action include production of pathogen-inhibitory substances, inhibition of pathogen attachment, inhibition of the action of microbial toxins, stimulation of immunoglobulin A, and trophic effects on intestinal mucosa. Each agent or preparation may have unique actions, with some bacterial strains being more or less effective than others. Trials included in meta-analyses are generally heterogeneous, especially with respect to the strain of probiotic used.(Di Caro 2005, Hill 2013, Oelschlaeger 2010, Ohland 2010) See also the Probiotics monograph.
Studies of preparations containing B. clausii spores support its use for the treatment and prevention of gut barrier impairment.(Lopetuso 2016) In contrast to lactic acid probiotics such as lactobacilli and bifidobacteria, the spore-forming Bacillus spp. probiotics are extremely resistant to acid and heat. B. clausii is characterized by some unique properties, including its resistance to bile and gastric acids, and its ability to grow in high-salt concentrations, adhere to the intestinal wall, promote epithelial proliferation, and survive transit through the GI tract. As a commercial product, these unique characteristics allow B. clausii to be stored without refrigeration or in a desiccated form without negatively affecting its viability.(Ghelardi 2015, Upadrasta 2016) Other attributes of Bacillus spp. include colonization, immunostimulation, and antimicrobial properties. B. clausii is resistant to commonly used antibiotics and demonstrates intrinsic resistance to penicillins, cephalosporins, aminoglycosides, and macrolides. It exhibits acquired resistance to tetracycline and chloramphenicol, and resistance to rifampin due to a chromosomal mutation. Resistance to lincomycin, isoniazid, cycloserine, and nalidixic acid has also been reported. B. clausii strains have been observed to release antimicrobial substances that are active against Staphylococcus aureus, Enterococcus faecium, and Clostridium difficile. B. clausii is capable of producing various vitamins, in particular the group B vitamins.(Di Caro 2005, Erceflora 2021, Lopetuso 2016)
Experimental studies reveal that B. clausii affects intestinal mucosa homeostasis via regulation of gene expression. In the small bowel mucosa, up- and down-regulation of genes involved in immune response and inflammation (eg, interleukin 1 [IL-1], IL-6, tumor necrosis factor, plasminogen activator), apoptosis, cell growth, and cell cycle (eg, RAS oncogenes, insulinlike growth factor, somatostatin), as well as cell adhesion, transcription, cell communication, and defense response functions, were observed.(Di Caro 2005)
A 3-week pilot study was conducted to evaluate potential effects of B. clausii on nasal symptoms, eosinophils, and use of antihistamines during the pollen season in 20 children with allergies (average age, 13.4 years). All 20 children were allowed levocetirizine 5 mg for symptomatic relief. Ten children were randomly assigned to receive 3 vials of oral B. clausii per day (2x109 spores/vial) in addition to levocetirizine. Compared with baseline, significant improvements in total nasal symptoms and nasal eosinophils were observed in the B. clausii group (P=0.049 and P=0.048, respectively); this improvement was not observed in the control group, which received only on-demand antihistamine (levocetirizine). Children receiving B. clausii also required fewer days of levocetirizine use than children in the control group (8.1 vs 11.1 days; P=0.034).(Ciprandi 2005)
Antigenotoxicity, specifically microbial inhibition of DNA-reacting compounds, is a functional property characterizing probiotic bacteria that is of clinical interest. Mutagens may induce change directly or indirectly, the latter being represented by many food-related compounds such as the mycotoxin aflatoxin B1 (AFB1) and the highly mutagenic heterocyclic amine 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) that results from the pyrolysis of protein foods (meat and fish). Relevant cell-mutagen interactions that contribute to genotoxicity include binding to bacterial cell components, reaction with bacterial metabolites, genotoxin-bacterial metabolite conjugation, and bioconversion to nonreactive moieties by bacterial enzymes. Antigenotoxicity is often considered strain dependent.(Cenci 2008)
Of the 21 strains of Bacillus spp. (eg, B. clausii, B. subtilis, Bacillus lentus, Bacillus pumilus, Bacillus firmus, Bacillus megaterium, Bacillus spp.) tested for inhibition of genotoxicity against 4 genotoxins (4-nitroquinoline-1-oxide [4-NQO], the nitrosamine N-methyl-N′-nitro-nitrosoguanidine [MNNG], AFB1, and MeIQ), all strains reduced genotoxicity without the species-strain specificities that have been reported for the probiotics lactobacilli and bifidobacteria. The bacilli exhibited higher antigenotoxicity against the direct genotoxin 4-NQO (greater than 92%) than the probiotic Lactobacillus rhamnosus GG (85.7%) and the dairy lactobacilli; however, L. rhamnosus was more active against MeIQ (62.8%) and AFB1 (80.8%) than the bacilli (range, 25% to 45% and 25% to 64.3%, respectively). L. rhamnosus was ineffective against MNNG, whereas the bacilli strains exhibited 78% to 99% genotoxin inhibitory activity.(Cenci 2008) B. clausii was also found to induce apoptosis in HCT-116 cell lines.(Yenuganti 2021)
In an in vitro experimental study, the cytotoxic effects of C. difficile and B. cereus were prevented by proteolytic compounds secreted by the probiotic B. clausii strain O/C; the hemolytic effect of B. cereus was also inhibited. The proteolytic enzyme activity was 4-fold higher during sporulation than during vegetative cell growth; after purification, the enzymatic-specific activity of the purified protease was 13-fold higher than the spore supernatant activity. The increased cell detachment and loss of mitochondrial dehydrogenase induced by C. difficile toxins was completely prevented in Vero cells by coincubation with B. clausii in a time-dependent manner; similar results were observed in Caco-2 cells. Likewise, high cell viability was retained when B. cereus was coincubated with B. clausii; time of coincubation was crucial to counteract the toxic effects.(Ripert 2016)
A prospective phase 2 clinical study conducted in India investigated the antidiarrheal activity of B. clausii (strain UBBC 07) in 27 adult patients with acute diarrhea (3 or more loose stools in 24 hours for longer than 7 days). Administration of one B. clausii capsule orally twice daily (2x109 colony-forming units [CFU]/capsule) for 10 days significantly improved mean duration of diarrhea from 34.8 to 9.3 minutes/day, frequency of diarrhea from 6.96 to 1.78 times/day, abdominal pain score from 3.22 (severe) to 0.74 (absent), and stool consistency score from 3.93 (watery) to 1.22 (soft) (P<0.0001 for all). Additionally, stool analysis revealed the absence of previously documented fat, resolution of mild mucus and occult blood, and absence of red and white blood cells. Entamoeba histolytica cysts were documented in the stools of 3 participants on day 1 but were completely eliminated by the end of the 10-day treatment. No serious adverse events were observed.(Sudha 2013)
In Italy, a randomized, single-blind controlled study of 571 children 3 to 36 months of age with acute diarrhea compared 5-day treatment efficacy of 5 probiotic preparations: L. rhamnosus; Saccharomyces boulardii; B. clausii; E. faecium; or a mixture of Lactobacillus delbrueckii var bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium bifidum. L. rhamnosus and the probiotic mix reduced total duration of diarrhea, daily stool output, and stool consistency (P<0.001); no effect was found with the other 3 formulations, including B. clausii. No adverse events were observed.(Canani 2007)
Data from a meta-analysis of 6 randomized controlled trials (N=898) that used B. clausii as a probiotic for the treatment of acute pediatric diarrhea demonstrated a significant reduction in the duration of diarrhea of −9.12 hours (95% CI, −16.49 to −1.75 hours; P=0.015) with B. clausii plus oral rehydration solution compared with children who received only oral rehydration solution (with and without zinc supplementation). Similarly, duration of hospitalization was statistically significantly reduced by 0.85 days (P=0.017) in the probiotic group (3 studies [n=291]). However, heterogeneity was significant for these 2 outcomes. The reduction observed in stool frequency (4 studies [n=697]) and number of vomiting episodes (2 studies [n=447]) was not significantly different between groups.(Ianiro 2018)
Dysbiosis (antibiotic-associated diarrhea)
A systematic review of published trials evaluating probiotic use for the prevention or treatment of various diseases included assessment of probiotic effectiveness in correcting dysbiosis (ie, antibiotic-associated diarrhea) resulting from disease or disruptive events. The review concluded that the degree of dysbiosis improvement is dependent on the enrolled population and timing of microbiological assays. The claim for correcting dysbiosis is poorly supported for most probiotic strains and requires further research. No trials assessing the ability of B. clausii to restore or improve normal microbiota were identified, and trial results regarding the eradication of H. pylori and the treatment of pediatric diarrhea were not significant.(McFarland 2014)
H. pylori treatment–induced adverse effects
A double-blind, randomized, placebo-controlled trial involving 120 symptom-free H. pylori–positive adults investigated the effect of oral bacteriotherapy with B. clausii on GI adverse effects occurring during H. pylori triple therapy (clarithromycin, amoxicillin, and rabeprazole). B. clausii probiotic therapy (1 vial of Enterogermina 3 times daily [each vial containing 2x109 spores of B. clausii]) was given adjunctively during the 7-day H. pylori treatment and for 7 days afterwards. H. pylori eradication rates were not different between groups; however, the occurrence of nausea was reduced by half, and the risk of diarrhea was reduced in the B. clausii group compared with placebo. Tolerability was also better with B. clausii after 2 weeks of treatment (P<0.05).(Nista 2004) The incidence of diarrhea was significantly reduced (by 39%) in patients undergoing 7-day H. pylori triple therapy who also received 14-day supplementation with B. clausii (Enterogermina) compared with the placebo group (P=0.03). No differences were noted in other GI symptoms during the first 7 days; however, epigastric pain was significantly lower at week 2 with the probiotic compared with placebo (P=0.037). B. clausii was well tolerated, with only patient-reported skin rash intensity being greater at week 2 than with placebo (P=0.008).(Plomer 2020)
Prophylactic administration of B. clausii to reduce the risk of late-onset sepsis in preterm infants was assessed in a double-blind, randomized, placebo-controlled trial in 244 preterm neonates (less than 34 weeks' gestational age) in India. Neonates were grouped as extreme preterm (27 to 30 weeks, 6 days' gestational age) and very preterm (31 to 33 weeks, 6 days' gestational age). B. clausii (Enterogermina) 2.4 x109 spores/day was administered until postnatal age of 6 weeks, discharge, death, or the occurrence of late-onset sepsis, whichever occurred first. No difference was observed in the incidence of definite and probable sepsis; however, full feeds were achieved at a faster rate with probiotic supplementation.(Tewari 2015)
According to the World Gastroenterology Organization guidelines, data suggest that probiotics as adjuvant therapy may be helpful in H. pylori eradication in adults (level 2 evidence).(WGO 2017)
In a small randomized, controlled study of patients with recurrent aphthous ulcer or oral candidiasis (N=80), adjuvant local application of B. clausii probiotic twice daily for 1 week significantly reduced erythema on day 5 compared with no adjuvant probiotic (P=0.001 for both subgroups). However, no significant difference between treatments was observed in either subgroup at the day 10 follow-up. Additionally, on day 5, the degree of pain was reduced in aphthous ulcer patients (P=0.0001), and oral thrush as well as oral burning sensation were reduced in oral candidiasis patients (P=0.006 and P=0.005, respectively). The number and size of aphthous ulcers did not differ between treatment groups. The authors noted that aphthous ulcer and oral candidiasis patients who did not receive "adjuvant" probiotic were treated locally with triamcinolone paste and clotrimazole mouth paint, respectively; it was not stated whether the probiotic group also received these pharmacological treatments and/or to what treatment the probiotic was an adjuvant.(Nirmala 2019)
Small-intestine bacterial overgrowth
The use of B. clausii for SIBO decontamination was assessed in 40 adults with chronic bloating, flatulence, abdominal discomfort or pain, and diarrhea plus an abnormal hydrogen glucose breath test, which is indicative of the presence of SIBO. Results of a glucose breath test 1 month after B. clausii therapy (1 vial of Enterogermina 3 times daily for 1 month [each preparation containing 2x109 spores of B. clausii]) revealed a 47% decontamination rate comparable to the 20% to 75% rate observed with many antibiotics. One patient reported constipation as an adverse effect.(Gabrielli 2009)
Upper respiratory tract infection
A single-blind, randomized, multicenter pilot study of 80 children 3 to 6 years of age who attended daycare centers (ie, a nursery or primary school) and who experienced recurrent respiratory infections investigated the safety and efficacy of B. clausii treatment on the incidence of recurring infections. All children were allowed desloratadine for symptomatic use. Half of the children were randomized to receive 1 vial of B. clausii (Enterogermina 2x109 spores per 5 mL) orally twice daily for 90 days. During the treatment period, the duration of respiratory infections was significantly reduced in children receiving B. clausii compared with children in the control group (mean, 11.7 days vs 14.4 days, respectively; P=0.037); however, while the number of respiratory infections was lower in the probiotic group, the difference was not significant (3.2 vs 3.9). During the 3-month follow-up period, significant improvements were observed in the duration of respiratory infections overall for the probiotic group (6.6 days vs 10.9 days; P=0.049) as well as for the control group (7.7 days vs 13.1 days; P=0.039). No treatment-related adverse events were observed.(Marseglia 2007)
B. clausii should be administered at regular intervals for a short time period. When used during treatment with antibiotics, B. clausii should be administered during the interval between antibiotic administrations.(Enterogermina December 2008, Erceflora 2021)
Manufacturer product information (Enterogermina and Erceflora)
4 to 6x109 spores/day (2 to 3 vials/day of suspension or 2 to 3 capsules/day).(Enterogermina December 2008, Erceflora 2021)
Children and infants
2 to 4x109 spores/day. Use is recommended for short periods of time.(Enterogermina December 2008, Erceflora 2021)
Acute diarrhea (adults)
One B. clausii capsule (2x109 CFU/capsule) administered orally twice daily for 10 days.(Sudha 2013)
H. pylori treatment–induced adverse effects (adults)
B. clausii (Enterogermina 2x109 spores/vial) 3 times daily given adjunctively to symptom-free H. pylori–positive adults during the 7-day H. pylori treatment (clarithromycin, amoxicillin, and rabeprazole) and for 7 days afterwards.(Nista 2004)
Nasal allergies (children)
B. clausii 3 vials/day (2x109 spores/vial) administered orally for 3 weeks to allergic children (average age, 13.4 years).(Ciprandi 2005)
Preterm neonates (less than 34 weeks' gestational age)
B. clausii (Enterogermina 2x109 spores per 5 mL oral suspension) administered at 2 mL every 8 hours mixed with enteral feeds (delivering 2.4x109 spores per day) until postnatal age of 6 weeks, discharge, death, or occurrence of late-onset sepsis, whichever occurs first.(Tewari 2015)
Small-intestine bacterial overgrowth (adults)
B. clausii (Enterogermina) 1 vial (2x109 spores) given orally 3 times daily for 1 month.(Gabrielli 2009)
Upper respiratory tract infection (children)
B. clausii (Enterogermina) 1 vial (2x109 spores per 5 mL oral suspension) orally twice daily for 90 days in children 3 to 6 years of age.(Marseglia 2007)
Pregnancy / Lactation
B. clausii can be used during pregnancy and lactation, and in breastfeeding infants.(Enterogermina December 2008, Erceflora 2021)
B. clausii has been used safely for up to 6 weeks in preterm infants (less than 34 weeks' gestational age) in a clinical study that enrolled 244 neonates.(Tewari 2015)
Antibiotics: Antibiotics may diminish the therapeutic effect of B. clausii. Consider therapy modification.(Enterogermina March 2020)
Probiotics are considered to be relatively safe, even in low-birth-weight infants and neonates. No adverse effects were noted in clinical trials of B. clausii or in the manufacturer's product information.
In 2014, the Food and Drug Administration issued a warning that advises practitioners of the potential risks of using dietary supplements containing live bacteria or yeast in immunocompromised patients (eg, premature infants).(Vallabhaneni 2015) Several cases of B. clausii bacteremia, at least one of which was fatal, have been reported in infants and adults subsequent to B. clausii probiotic use. Most had underlying comorbidities or a compromised immune system; however, a case has also been reported in an immunocompetent 17-month-old female with no prior medical history.(Joshi 2019, Khatri 2021, Princess 2020)
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