Novel insight on probiotic Bacillus subtilis: Mechanism of action and clinical applications

Abstract

Probiotics are the living microorganisms that provide health benefits to the recipient. Lactobacillus and
Bifidobacterium genera have been used since long for the competitive exclusion of pathogens from the
gut. However, their limitations such as sensitivity to gastric acid, temperature, slow growth, and specific
stability conditions lead to search for a novel probiotic that is stable through its shelf-life as well as
during gastrointestinal transit; hence, offering better efficacy. Bacillus bacteria have strong scientific
data which substantiates the validity of the use as preferred probiotics. In recent times, there has been
significant progress in scientific evaluation and studies on probiotic Bacillus subtilis, revealing possible
mechanisms of action like antimicrobial effect by synthesis of antimicrobial substances, antidiarrheal effect,
immunostimulatory effect, competitive exclusion of pathogens, prevention of intestinal inflammation, and
normalization of intestinal flora. Numerous preclinical and clinical studies on B. subtilis have shown its
promising efficacy in the treatment and prevention of diarrhea of various etiologies. B. subtilis is certified
as generally recognized as safe by Food and Drug Administration and features in the European Food Safety
Authority Qualified Presumption of Safety, hence suggesting as safe for human use. All of these beneficial
attributes make B. subtilis the most attractive probiotic species for various clinical conditions.

Full text

© 2016 Journal of Current Research in Scientific Medicine | Published by Wolters Kluwer - Medknow 65
Novel insight on probiotic
Bacillus
subtilis: Mechanism of
action and clinical applications
Manoj A. Suva, Varun P. Sureja, Dharmesh B. Kheni
Department of Pharmacology, K. B. Instute of Pharmaceucal Educaon and Research, Kadi Sarva Vishwavidyalaya University,
Gandhinagar, Gujarat, India
INTRODUCTION
The term “probiotics” was derived from the Greek word,
meaning “for life.”[1] According to the WHO/FAO, probiotics
are: “Live microorganisms which when administered in adequate
amounts confer a health benefit on the host.”[2] Various factors
such as environmental, nutritional and/or metabolic changes
favor pathogen proliferation and that disturb equilibrium
between beneficial and pathogenic flora leading to disease
conditions. Synthetic antibiotics were the first option to
control pathogenic overgrowth; however, the unregulated
use of these compounds induced multi‑drug resistance in
pathogenic bacteria. Hence, antibiotic utilization needs to
be well regulated. In this sense, the utilization of beneficial
bacteria (probiotics) has emerged as an alternative based on
the beneficial good results obtained with it.[3]
Lactobacillus
Address for correspondence:
Mr. Manoj A. Suva, Department of Pharmacology, K. B. Instute of Pharmaceucal Educaon and Research, Kadi Sarva Vishwavidyalaya University,
Gandhinagar ‑ 382 024, Gujarat, India. E‑mail: manojsuva_0211@yahoo.co.in
Received: 22.10.2016, Accepted: 18.11.2016
Review Article
Probiotics are the living microorganisms that provide health benefits to the recipient.
Lactobacillus
and
Bifidobacterium genera have been used since long for the competitive exclusion of pathogens from the
gut. However, their limitations such as sensitivity to gastric acid, temperature, slow growth, and specific
stability conditions lead to search for a novel probiotic that is stable through its shelf-life as well as
during gastrointestinal transit; hence, offering better efficacy.
Bacillus
bacteria have strong scientific
data which substantiates the validity of the use as preferred probiotics. In recent times, there has been
significant progress in scientific evaluation and studies on probiotic
Bacillus
subtilis, revealing possible
mechanisms of action like antimicrobial effect by synthesis of antimicrobial substances, antidiarrheal effect,
immunostimulatory effect, competitive exclusion of pathogens, prevention of intestinal inflammation, and
normalization of intestinal flora. Numerous preclinical and clinical studies on
B. subtilis
have shown its
promising efficacy in the treatment and prevention of diarrhea of various etiologies.
B. subtilis
is certified
as generally recognized as safe by Food and Drug Administration and features in the European Food Safety
Authority Qualified Presumption of Safety, hence suggesting as safe for human use. All of these beneficial
attributes make
B. subtilis
the most attractive probiotic species for various clinical conditions.
Key Words: Antidiarrheal effect, antimicrobial substances,
Bacillus
subtilis, immunomodulation
Abstract
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How to cite this article: Suva MA, Sureja VP, Kheni DB. Novel insight on
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Suva, et al.: Probiotic Bacillus subtilis clinical applications
66 Journal of Current Research in Scientific Medicine | Jul-Dec 2016 | Vol 2| Issue 2
and
Bifidobacterium
genera have been used almost exclusively
for the competitive exclusion of pathogens from the gut of
humans and animals. However, there are some major challenges
related to manufacturing probiotic formulations containing
lactobacilli and
Bifidobacteria spp.,
as below:
• Thesemicroorganismsaremicroaerophilicorstrict
anaerobic, therefore, their handling and production is
complex and could be a challenge
• Bothmicroorganismsareslowgrowers
• Sensitivetotemperaturehenceproductmustbemaintained
at low temperatures and shelf‑life in general is short
• Manyoflactobacilliand
Bifidobacteria
are sensitive to
gastric juice during gastrointestinal (GI) tract transit.[4]
Bacillus
bacteria are highly diverse group of microorganisms,
known for more than 100 years. There are strong scientific data
which substantiates the validity of the use of
Bacillus
bacteria
as probiotics.[5] Only a few of the 100 species contained in
the
Bacillus
genus are used as probiotics in humans such as
Bacillus subtilis, Bacillus licheniformis, Bacillus coagulans,
Bacillus cereus var. toyoi, Bacillus natto (subtilis), Bacillus
clausii, Bacillus pumilus,
and
Bacillus cereus
.[6] In recent
decades, scientific studies on probiotic
B. subtilis
have made
significant progress to elucidate the activity spectrum which
makes this bacterium the most attractive probiotic for clinical
use. In this review, we have present data from experimental and
clinical research that may allow making an impression of the
therapeutic potential of
B. subtilis
.
BACILLUS SUBTILIS
BACTERIA IN NATURE
Bacillus
constitutes a diverse group of rod‑shaped, Gram‑positive
bacteria, characterized by their robust spore‑forming ability.[3]
Bacillus
genus bacteria are most widespread microorganisms in
nature.
Bacillus
species are predominant in soil and also have
been isolated from water, air, and food products like wheat, grain,
wholemeal, soya beans, and milk microflora. Bacilli consistently
enter the GI and respiratory tracts of healthy people with food,
water, and air. Isolation of
B. subtilis
from the human GI tract
was reported for healthy adults and children. The number of
bacilli in the gut can reach 107 CFU/g, comparable to lactobacilli
count. Thus, researchers considered
Bacillus
to be one of the
dominant components of the normal gut microflora.[5] The
B.
subtilis
genome is totally sequenced, leading to the generation
of great amount of basic knowledge and also developments of
molecular and genetic methodologies.[3]
BACTERIAL SPORE FORMATION
Bacterial spores are formed as a means to survive extreme
environmental conditions for long‑term survival otherwise
that conditions kill vegetative bacteria. Sporulation is very
much dependent upon the nutrients availability in the
immediate vicinity of the live cell. According to Cutting
et al
.
(2009), decrease in nutrients is sensed by the bacterium and
it enters an irreversible program of development that results
in the production of spores as shown in Figure 1.[7] Bacterial
endospore contains a condensed and inactive chromosome at
its core. Surrounding the spore, layer of peptidoglycan‑rich
cortex and one or more layers of proteinaceous material is
present referred as the spore coat. During the lack of nutrient
condition, growing vegetative cell (VC) undergoes a series of
morphological changes that forms a forespore (F) within the
mother cell (MC) of the sporangium and then after some time
spore (S) is released by lysis of the MC.[7]
BACILLUS SUBTILIS
SPORE FORMATION AND
ITS ADVANTAGES
B. subtilis
spores are highly resistant to temperature, extreme
pH, gastric acid; bile and solvents, hence keep viability in the
gut.[3,5]
B. subtilis
can be stored for long time periods without
refrigeration.[3]
BACILLUS SUBTILIS
SPORE GERMINATION AND
PROLIFERATION IN GASTROINTESTINAL TRACT
Immunological data showed that
B. subtilis
spores germinate
in the mouse gut and proliferate and able to grow and
resporulate.[8] Casula and Cutting observed germination of
B. subtilis
spores as VCs in the mouse jejunum and ileum using
a competitive reverse transcription polymerase chain reaction
targeting a genetically engineered chimeric gene, ftsH‑lacZ,
which is only expressed by VCs.[9] Ozawa
et al.
found that spores
of
B. subtilis
strain BN germinate and multiply to some extent
in the GI tract of pigs.[10] Leser
et al
. showed that
B. subtilis
germinate and grow in proximal part of the pig GI tract.[11]
MECHANISM OF ACTION OF PROBIOTIC
BACILLUS SUBTILIS
Possible mechanisms of action include antimicrobial effect
by synthesis of antimicrobial substances, antidiarrheal effect,
Figure 1: Sporulation life cycle of bacterial spore formers
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Suva, et al.: Probiotic Bacillus subtilis clinical applications
Journal of Current Research in Scientific Medicine | Jul-Dec 2016 | Vol 2| Issue 2 67
immunostimulatory effect, competitive exclusion of pathogens,
prevention of intestinal inflammation, and stimulation of
growth of intestinal normal flora.[11]
B. subtilis
has unique
properties such as spore formation, versatility of growth
nutrients utilization, high level of enzymes production, fast
growth rate, and growth in aerobic and anaerobic conditions.[3]
Synthesis of antimicrobial agents
Bacillus
bacteria play a significant role in the gut because of
their high metabolic activity. The activity of
Bacillus
is mainly
determined by their ability to produce antibiotics.
B. subtilis
is the most productive species which devotes 4%–5% of
genome to antibiotic synthesis and produce 66 antibiotics.
Bacillus
antibiotics have different structure and spectrum of
antimicrobial activity.[5] The potential of
B. subtilis
to produce
antibiotics has been recognized for 50 years. Antimicrobial
agents synthesized and secreted by
B. subtilis
are listed in
Table 1.[12‑14]
B. subtilis
synthesized antimicrobial substances
have antimicrobial effects against broad spectrum of pathogens.
These substances are natural part of human antimicrobial
defense system hence the possibility of developing pathogen
resistance or unwanted side effects is less. Hence, probiotic
B. subtilis
is ideal therapeutic option because of their broad
spectrum of activity and specific and rapid killing activity
against various pathogens.[14]
B. subtilis
probiotic properties
are strain‑specific.[3] Pectinolytic enzymes have been isolated
from
B. subtilis
. Bacilli produce amino acids, including essential
amino acids and vitamins.[5]
Immunostimulatory effect
B. subtilis
enhances the protection against pathogens by
stimulating nonspecific and specific immunity. A number of
studies in humans and animal models have provided strong
evidence that oral administration of
Bacillus
spores stimulates
the immune system. Spores of
B. subtilis
trigger specific
humoral and cell‑mediated immune responses. The interaction
between
B. subtilis
spores and macrophages plays an important
role in development of both innate and adaptive immune
responses of the host. Numerous studies have demonstrated
that
B. subtilis
leads to macrophage activation.
B. subtilis
B10,
B. subtilis
BS02, and
B. subtilis
(
natto
) B4 spores may
possess immunomodulatory activities by the induction of
pro‑inflammatory cytokines and exerts probiotic activities
through activated macrophage functions. In addition,
B. subtilis
showed no apparent cytotoxicity against RAW 264.7 cells
and thought to be safe.[15‑17]
B. subtilis
MBTU PBBM1
spores administration leads to augmentation of antibody
response (antibodies IgG and IgA) and also proliferation of
the T lymphocytes which indicates
B. subtilis
MBTU PBBM1
spores have the potential to improve both the humoral and
cellular immunity in mice.[18] Commensal bacteria play an
important role in the development of the gut‑associated
lymphoid tissue (GALT) and important for both innate and
adaptive immunity.
B. subtilis
promotes active lymphocyte
proliferation within GI tract.
B. subtilis
administration in
appendix of germfree rabbits has been shown to promote
GALT development. This evidence showed that
Bacillus
species are important for development of robust gut‑associated
lymphoid system (GALT) and promote a potent immune
response.[19] The effect of lymphocyte activation by
B. subtilis
spores was both quantitatively and qualitatively similar to
mitogens phytohaemagglutinin and Concanavalin A.
B. subtilis
spores stimulated cytokine production
in vitro
and after oral
administration in mice.[5] Oral treatment with
B. subtilis
spores
increased expression of activation markers on lymphocytes in
dose‑dependent manner in healthy volunteers.[20]
B. subtilis
spores‑induced systemic antibody response to tetanus toxoid
fragment C and ovalbumin in mice. These data suggest that
B.
subtilis
spores are an efficient mucosal and systemic adjuvant
for enhancing humoral immune responses.[21]
Maintenance of intestinal homeostasis and prevention
of intestinal inflammation
B. subtilis
derived quorum‑sensing pentapeptide, competence
and sporulation factor (CSF) activate key survival pathways
including p38 MAP kinase and protein kinase B (Akt) in
intestinal epithelial cells of the host. CSF also induces heat
shock proteins, which protect intestinal epithelial cells against
injury and loss of barrier function and hence provide the
ability to maintain intestinal homeostasis.[22]
B. subtilis
quorum
sensing molecule CSF reduced epithelial injury caused by
intestinal inflammation and improved the survival rate of mice
with lethal colitis. This indicates that
B. subtilis
are potentially
useful for treating intestinal inflammation.
B. subtilis
is
beneficial for maintaining intestinal homeostasis and host
health and can be utilized to treat antibiotics‑induced colitis,
inflammatory bowel disease (IBD) (including Crohn’s disease
and ulcerative colitis) and necrotizing enterocolitis.[23]
Bacillus
species (
B. subtilis,
Bacillus
firmus,
Bacillus
megaterium,
and
B. pumilus
) have been shown to convert genotoxic compounds
to unreactive products
in vitro
.[24] Orally administered
B. subtilis
spores were effective in decreasing infection and enteropathy in
suckling mice infected with
Citrobacter rodentium
(a model for
the traveler’s diarrhea pathogen enterotoxigenic
Escherichia coli
)
which is known to cause epithelial lesions, crypt hyperplasia,
and mortality.[7,25] Intestinal mucosal barrier dysfunction
associated with IBD. Mucosal biopsies taken from IBD patients
showed loss of key epithelial tight junction (TJ) proteins such
as claudin‑1, occludin, junctional adhesion molecule (JAM)‑A,
and zona occludens (ZO)‑1. Effects of
B. subtilis
on epithelial
TJs and intrinsic regulatory mechanisms of the intestine were
studied in dextran sulfate sodium‑induced colitis in Balb/c
mice.
B. subtilis
significantly reduced disease activity index
scores and graded histologic damage.
B. subtilis
improved
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barrier function by upregulating expression of epithelial TJs
proteins (claudin‑1, occludin, JAM‑A, and ZO‑1) and reduced
intestinal epithelial damage by downregulating cytokine
expression (interleukin‑6 [IL‑6], IL‑17, IL‑23, and tumor
necrosis factor‑α).[26]
Maintenance of intestinal normal flora
B. subtilis
positive effect on the maintenance of the normal
intestinal flora has been demonstrated in many studies.
B. subtilis
3 strain showed efficacy against pathogenic cultures
of
E. coli
and
Campylobacter
species during treatment of
Table 1: Antimicrobial agents synthesized and secreted by Bacillus subtilis
Category of
antimicrobial agents
Antimicrobial agents Mechanism of
action
Spectrum of antimicrobial activity
Ribosomal
synthesized peptides
Bacteriocins: Type A
lantibiotics
Subtilin, ericin A, ericin S Voltage‑dependent
pores into the
cytoplasmic
membrane
Gram‑positive bacteria, antiviral, and antimycoplasma
activities
Ribosomal
synthesized peptides:
Type B lantibiotics
Mersacidin Inhibition of cell wall
synthesis
Gram‑positive bacteria, including methicillin‑resistant strains
of
S. aureus
and vancomycin resistant strains of
Enterococci
Unusual lantibiotics Subtilosin A Antimicrobial activity
by interacting with
membrane‑associated
receptors
Gram‑positive bacteria, strong bactericidal activity against
L. monocytogenes
Sublancin 168 ‑ Gram‑positive bacteria, pathogens such as
B. cereus
,
S. pyogenes
and
S. aureus
Bacillocin 22 ‑ ‑
Nonribosomal
synthesized peptides
Surfactin Powerful
biosurfactant ‑ it
exerts a
detergent‑like
action on biological
membranes
Antiviral and antimycoplasma activities, inhibit biofilm
formation of human pathogen
S. enterica
Bacilysin Inhibits glucosamine
synthase involved
in synthesis of
nucleotides, amino
acids and coenzymes
and resulting in lysis
of microbial cells
S. aureus and C. albicans
Iturine lipopeptides:
Mycosubtilin, iturines,
bacillomycins
‑ Strong antifungal and hemolytic and limited antibacterial
activities
Fengycin (plipastatin) ‑ Antimicrobial and fungicidal action
Rhizocticins ‑ Antifungal activity
Mycobacillin (B3) ‑ Antibacterial and antifungal activities
Corynebactin (bacillibactin),
3,3’‑neotrehalosadiamine (168),
difficidin, TL‑119 (A‑3302‑B)
‑ ‑
Miscellaneous
antibiotic compounds
Polyketides: Difficidin,
oxydifficidin, bacillaene
‑ Antibacterial activity against both aerobic and anaerobic
organisms
Amicoumacin ‑ Antibacterial activities, S. aureus and H. pylori
Bacilysocin ‑ ‑
BSAP‑254 ‑ Antagonistic effect against the food borne pathogens
Entianin ‑ Strong antibacterial activity against S. aureus, E. faecalis,
and other Gram‑positive pathogens
Subpeptin JM4‑A, subpeptin
JM4‑B
‑ Active against broad spectrum of bacteria, including
Salmonella, B. cereus, S. aureus
Antifungal protein B29I ‑ Inhibitory activity on mycelial growth in F. oxysporum,
Rhizoctonia solani and other fungi
Bacteriocin‑like substances Gram‑positive and Gram‑negative bacteria
AMP IC‑1 ‑ Antagonistic to B. cereus
AMPNT‑6 ‑ Active against marine food borne pathogen
Bac 14B ‑ Useful for seed disinfection
‑: Not yet identified, S. aureus: Staphylococcus aureus, L. monocytogenes: Listeria monocytogenes, S. pyogenes: Streptococcus pyogenes,
S. enterica: Salmonella enterica, C. albicans: Candida albicans, H. pylori: Helicobacter pylori, E. faecalis: Enterococcus faecalis, B. cereus: Bacillus
cereus, F. oxysporum: Fusarium oxysporum, R. solani: Rhizoctonia solani
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experimental infections in mice and maintained normal
microflora in the animals during receipt of antibiotic therapy.
In vitro
studies of
B. subtilis
, 3 showed a wide spectrum of
antagonistic activity toward the tested pathogens and did not
inhibit normal microflora.[27]
B. subtilis
MA139 significantly
increased the number of
Lactobacillus
and reduced the content
of
E. coli
in the intestines and feces in pigs.[28]
B. subtilis
KN‑42 significantly increased lactobacilli counts and reduced
E. coli
counts and improved the growth performance and GI
health of piglets.[29]
B. subtilis
KD1 improved intestinal flora
by significantly increasing lactobacilli counts and reducing
E. coli
counts and improve the growth performance in
broilers.[30]
B. subtilis
var. natto
in mice influenced the fecal
microflora, specifically
Bacteroides
and
Lactobacillus
species.
Mice fed with an egg white diet showed decrease in numbers
of
Lactobacillus
spp., while
B. subtilis
var. natto
spores
supplemented diet stabilized it. Using a casein diet, the numbers
of Bacteroidaceae increased. This result indicated that
B.
subtilis
var. natto
could be beneficial in maintaining the natural
microflora.[24] Therefore, an increase in
Lactobacillus
counts
and decrease in
E. coli
counts may result in a lower diarrhea
incidences.[29]
Salmonella
is a major foodborne pathogen
which can cause severe illness in humans such as enteric fever,
bacteremia, focal infection, and enterocolitis.
B. subtilis
NC11
exhibits strong inhibition activity against
Salmonella
enteritidis
infection to intestinal epithelial cells.[31]
B. subtilis
CU1
effects on intestinal mucosal immune system, and microbial
balance were evaluated in antibiotic‑induced dysbiosis mouse
model.
B. subtilis
CU1 spores (3 × 109 spores/day/mouse)
administered before and during the antibiotic treatments.
Treatment with the
B. subtilis
CU1 strain decreases the
antibiotic‑induced intestinal inflammation.
B. subtilis
CU1
shown to normalize the B220+MHCII+B‑cells in mesenteric
lymphoid node and F4/80+ macrophages in Peyer’s patches
in the antibiotic group.
B. subtilis
CU1 treatment reduced
antibiotic‑induced alterations in the gut microbiota. This result
suggests that
B. subtilis
CU1 may contribute to the reduction
of antibiotic‑induced inflammation through normalization of
mucosal immune responses and intestinal microbiota.[32] Taking
into account beneficial properties of
B. subtilis
, this bacterium
is a potential probiotic candidate to be considered for various
clinical conditions.
CLINICAL TRIALS OF
BACILLUS SUBTILIS
B. subtilis
therapy was highly effective in treatment of various
infectious pathologies in patients.[33] Clinical efficacy of
B. subtilis
was summarized as an antidiarrheal agent, used in
different counties.
B. subtilis
is one of the most important
microorganisms for the treatment and prophylaxis of intestinal
disorders in humans.[34]
B. subtilis
was more effective in
treatment of acute diarrhea than lactobacilli.[5]
Regularity of bowel movements
Labellarte
et al
., carried out randomly assigned, double‑blind
placebo‑controlled trial of
B. subtilis
(approximately 1.9 × 109
CFU/capsule) in 40 healthy male and female adults for an
average of 20 days. The study showed that daily consumption
of
B. subtilis
was effective in promoting regularity of bowel
movements and well tolerated.[35]
Survival in the gastrointestinal tract
Hanifi
et al
., carried out randomized, double‑blind,
placebo‑controlled trial of
B. subtilis
R0179 in 81 healthy
adults (18–50 years old). Subjects received
B. subtilis
R0179
at dose of 0.1, 1 or 10 × 109 CFU/capsule/day or placebo
for 4 weeks. Fecal viable counts of
B. subtilis
R0179 showed
a dose‑dependent GI survival response and fecal viable counts
were 0.1 × 109 (4.6 ± 0.1 log10 CFU/g), 1 × 109 (5.6 ± 0.1
log10 CFU/g) and 10 × 109 (6.4 ± 0.1 log10 CFU/g)
respectively (
P
< 0.0001).
B. subtilis
R0179 survives passage
through the human GI tract and is safe and well tolerated in
healthy adults at intake from 0.1 to 10 × 109 CFU/day.[36]
Diarrhea and antibiotic‑associated diarrhea
Clinical efficacy of
Bacillus
bacteria in the treatment of GI
infections has been reported. Mazza (1994) summarized
results of numerous studies and concluded that
B. subtilis
are
one of the most important microorganisms for the treatment
and prophylaxis of intestinal disorders in humans.[34] In
clinical study,
B. subtilis
and
B. licheniformis
(2 × 109
microbial cells; Biosporin) were administered to the patients
with acute enteric infections. Results showed the pronounced
curative effect of
Bacillus
probiotics manifested by the rapid
normalization of stool, abdominal pain relief, and decrease in
intestinal dysbiosis.
Bacillus
probiotics found to be safe and
well tolerated.[37]
B. subtilis
and
B. licheniformis
(Biosporin)
has been also evaluated for effect on intestine microflora in
acute digestive disorders and dysbacterioses in 53 newborn
children with perinatal pathology. Results showed high
therapeutic and prophylactic efficiency for dysbacterioses
and diarrheas in the newborn children without side effects.[38]
One of the most common side effects of antibiotic therapy is
antibiotic‑associated diarrhea (AAD). The frequency of AAD
depends on the type of antibiotic used and varies from 25% to
as high as 44%. The route of antibiotic administration (oral or
parenteral) does not affect the rate of AAD, and no difference
has been found in the frequency of AAD with respect to age
and gender. The severity of AAD may vary from uncomplicated
diarrhea to
Clostridium difficile
‑associated pseudomembranous
colitis. The main mechanism for the development of AAD is
significant changes in the composition and quantity of the gut
microbiota during the treatment with antibiotics. AAD may
be caused by different enteric pathogens such as
Salmonella
spp.,
Staphylococcus aureus
,
Candida albicans
,
Clostridium
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perfringens
, and
Klebsiella
spp.
Bacillus
bacteria have attracted
the growing attention of researchers as effective probiotics for
the treatment and prevention of enteric infections. Research
study showed high efficacy of the
Bacillus
probiotic
B. subtilis
3 and
B. licheniformis
31 (predominant amount of
B. subtilis
3 in 50:1 parts; Biosporin) in the treatment of acute intestinal
infections.[39] In clinical trial,
B. subtilis
spores (4 × 109)
administered to 11 children aged 3–24 months for 5 days
along with antibiotic and alone antibiotic was given to 8
subjects. Results showed that number of stools increased in
alone antibiotic group while in
B. subtilis
along with antibiotic
group no such changes were observed. Bacteriotherapy along
with antibiotic also increased saccharolytic flora, aerobic and
anaerobic flora.[40] Horosheva
et al
. carried out a randomized,
double‑blind, placebo‑controlled clinical trial on outpatients
aged≥45yearswhowereprescribed≥1oralorintravenous
antibiotics for at least 5 days. One group of patients (
n
= 90)
received probiotic
B. subtilis
3 (2 × 109 CFU/vial), 2 times
a day from beginning 1 day before initiation of antibiotic
therapy and ending 7 days after discontinuation of antibiotic.
Results showed that AAD developed in 25.6% (23/90)
patients in placebo group while in significantly lower
AAD rate 7.8% (7/90) patients reported in
B. subtilis
3
group (
P
< 0.001).
B. subtilis
3 significantly reduced the
incidence of nausea, vomiting, bloating, and abdominal pain.[39]
There have been 23 clinical trials involving over 1800 patients
for probiotic preparation containing a combination of
B.
subtilis
R0179 and other probiotic. It has been used in the
improvement of symptoms associated with chronic diarrhea
and irritable bowel syndrome, as a coadjuvant therapy with
sulfasalazine and mesalazine to improve remission times in
mild to moderate ulcerative colitis and to improve compliance
with conventional triple therapy for
Helicobacter pylori
eradication.[41]
Stimulation of immune responses
Lefevre
et al
. (2015) carried out randomized, double‑blind,
placebo‑controlled, parallel‑arms trial on 100 elderly subjects
and allocated to receive
B. subtilis
CU1 (2 × 109 spores daily)
or placebo for short course of 10 days followed by 18 days of
treatment break per month and this scheme was repeated for
4 times during the trial (4 months). Biological sample analysis in
subset of 44 subjects showed that
B. subtilis
CU1 significantly
increased secretory IgA level in saliva and stools compared
to the placebo as shown in Figures 2 and 3.[42] SIgA is a key
element in the maintenance of gut microbiota homeostasis and
in the protection of GI and respiratory tracts against pathogens.
B. subtilis
CU1 had been shown to increase IgA producing
B cells in Peyer’s patches in mice (Racedo SM and Urdaci MC,
unpublished observations), it can be postulated that
B. subtilis
CU1 strengthens the generation of α4β7+IgA+B‑cells in
the Peyer’s patches of the small intestine. The homing of IgA
producing B cells to the intestinal mucosa and the salivary glands
leads to high SIgA levels in saliva and stools.
B. subtilis
CU1
significantly increased serum interferon‑γ (IFN‑γ) and stimulated
systemic immune response. IFN‑γ plays an important role in
the host defense against several infectious diseases including
viral infection and has a variety of immune functions such as
stimulation of macrophages and natural killer cells. A
post hoc
analysis in subset of 44 subjects showed a decreased frequency of
respiratory infections in the
B. subtilis
CU1 group compared to
the placebo group. This result suggests that
B. subtilis
CU1 may
be an effective and safe way to stimulate immune responses.[42]
SAFETY OF
BACILLUS SUBTILIS
According to European Scientific Committee on Animal
Nutrition,
B. subtilis
was tested and showed no evidence
of toxicity. Acute and chronic toxicity studies in animals
also indicated safety of these strains.
B. subtilis
is generally
recognized as safe by the Food and Drug Administration (FDA),
meaning it is not harmful to humans.[3]
B. subtilis
species is
considered safe by the European Food Safety Authority (EFSA)
Qualified Presumption of Safety. Thus,
B. subtilis
strain
may be considered as nonpathogenic and safe for human
consumption.[43]
B. subtilis
could be considered as a perfect
multifunctional probiotic bacterium for humans.[3]
Figure 2: Increase in secretory IgA level in saliva Figure 3: Increase in secretory IgA level in stools
[Downloaded free from http://www.jcrsmed.org on Saturday, January 14, 2017, IP: 101.57.137.50]

Suva, et al.: Probiotic Bacillus subtilis clinical applications
Journal of Current Research in Scientific Medicine | Jul-Dec 2016 | Vol 2| Issue 2 71
SUMMARY
The world market for probiotics supplements has been growing
over the last two decades based on their important clinical
merits. Lactobacillus and Bifidobacterium are the most used
genera, mainly for their ability to exclude pathogens. However,
they do not have multifunctional probiotic capacities as B.
subtilis. Bacillus bacteria are increasingly attracting attention
of researchers as promising probiotics due to their strong
antimicrobial, antidiarrheal and immunostimulatory effects,
ability to stimulate growth of natural flora and prevent
intestinal inflammation; besides having an excellent stability
profile in otherwise unfavorable conditions. Moreover, it
has established efficacy and safety in numerous randomized,
double‑blind clinical trials, as validated and approved by
authorities like FDA and EFSA. In this sense, B. subtilis has the
potential to emerge as the “perfect multifunctional probiotic
bacteria” for various clinical conditions in humans.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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