The Safety And Efficacy of Bacillus as Probiotics

A Brief Review

by Lee B. Dexter

Summary

Bacterial strains of the genus Bacillus are currently being marketed in probiotic formulations for both humans and livestock. International teams of scientists have been actively investigating their use to provide bacteriotherapy for gastrointestinal disorders. In combination with other probiotics the spore-forming Bacilli enhance the growth of Lactobacillus sp., and suppress the growth of harmful microorganisms like resistant Staphylococcus aureus. Various Bacillus species have a long history of safe use in human nutrition, and are widely recognized as nonpathogenic by regulatory authorities. Bacilli are often found in symbiotic groups of naturally occurring probiotics called consortia. Consortia represent stable cultures of bacteria that produce desired heath effects in the gastrointestinal tracts of consumers who consume them on a regular basis. One source of a natural consortium of soil-based probiotics supplements is Body Biotics by Life Science Products, Inc. This product may be the only probiotic supplement providing a natural consortium of probiotics on the market today.

Introduction

Probiotics, or "friendly bacteria" are now being recognized in the United States for their ability to improve the health of consumers. Americans are now finding out, what has long been known in Europe, that specific species and strains of bacteria can improve resistance to pathogenic bacteria, aid in lactose digestion, modulate the immune system, prevent overgrowth of bacteria in the small intestine, reduce blood lipids, reduce blood pressure, and help to alleviate allergies, urogenital infections, Helicobacter pylori infections, and hepatic encephalopathy.23 Acceptance of these phenomena by scientists in the U.S. has been slow in coming. But the evidence has been mounting; so much so, that the mainstream, Institute of Food Technologists has issued an Expert Panel Report on the most common of these organisms and has sponsored a symposium on their use at a recent annual meeting.24

Clearly, there is much more to learn about how these organisms interact with the body, and with each other to produce these effects. The most advanced formulators of probiotic products have recognized the fact that each person carries about three to four and a half pounds of active bacteria in their colon, and that the products of these bacteria can have a profound effect on the body's health and metabolism.3 It is for that reason that researchers around the world have been investigating the safety and efficacy of potential probiotic species, including those in the genus Bacillus.19

Bacillus as Probiotics

Several strains of Bacillus sp. are in use as probiotics supplements today in the U.S., Europe, and Southeast Asia. 10, 11, 13 These probiotics include strains of the species subtilis and licheniformis.12 Strains of these organisms have been included in the group of probiotic organisms for several reasons. First viable spores of both species have been found to enhance the growth of various species of Lactobacillus, suppress the growth of pathogenic organisms, such as E. coli 078:K80 and Helicobacter pylori, and produce antibiotic substances, which retard the growth of harmful organisms, and help the body restore its natural flora. 14, 10, 11, 21

For example, both Bacillus subtilis and Bacillus licheniformis are widely used in probiotic formulas in the livestock and poultry industries, especially in Europe, where the feeding of antibiotic growth promoters has been banned. In this instance, the spores of these organisms act as competitive exclusion agents. One study showed that 1-day old chicks, that consumed 2.5 X 10^8 (250,000,000) Bacillus subtilis spores, were able to completely resist infection by the pathogenic E. coli strain mentioned above.10, 11

As to Bacillus licheniformis, any reader who has ever had skinned knees will recognize one of the antibacterial substances produced by this organism. Bacitracin has been incorporated into antiseptic ointments for several decades. 1

Both Bacillus subtilis and Bacillus licheniformis are spore-forming bacteria found in the soil, and particularly in the case of Bacillus subtilis may also be a frequent resident on human skin.1, 4, 10 Since these organisms are not as familiar to the consumer as Lactobacillus, the natural question that arises is, "Are these organisms safe to take as probiotics"?

When the U.S. Food and Drug Administration reviews the safety of a food ingredient, the agency considers whether or not the food substance has a history of safe consumption. That is, was there significant consumption of the food ingredient either within the U.S. or other countries prior to January 1, 1958? If not, does the preponderance of scientific evidence indicate that there is a consensus among scientists that the particular material is safe?

In food safety questions, the identity of the material to be considered is extremely important. This principle is even more important, where the safety of bacteria is concerned. Bacteria are identified according to a taxonomic system. This means that all characterized bacteria are classified by genus, species, and a strain within a species. Each species may have hundreds or even thousands of strains.

An example may illustrate this point. The media has made nearly everyone familiar with E. coli. However, E. coli is a normal resident of the human body. It occurs in numbers of 10^8x8.6/ gram of feces (860,000,000/gram) in the human colon.3

The vast majority of the thousands of strains of the species coli are not disease producing. Further, recent peer-reviewed published research has shown that nonpathogenic non-toxigenic E. coli can be used as a probiotic to promote the health of the gastrointestinal tract, and can be taken orally to treat various diseases. 6, 8, 15, 17, 22, 23

One paper showed that the immune system was stimulated in a positive direction, when humans consumed the bacteria at levels of 1.0 X 10^8 (100,000,000) cells daily for 14 days.15 Nonpathogenic wild-type E. coli strains have been used as probiotics in Europe for at least two decades. Yet, most individuals remember only the most well known pathogenic strain of E. coli O157:H7. This strain is a true pathogen, in that it is capable of crossing a barrier in a healthy individual.20 While many microorganisms, including widely used industrial species like those responsible for the production of bread and beer, can be associated with incidental infections in immunocompromised people, they do not fit the definition of a pathogen, as described above.

Regulatory agencies around the world have considered these distinctions, when they recognized the safety of wild-type strains of both Bacillus subtilis and Bacillus licheniformis.5, 10

Wild type strains of both organisms (and their metabolic products) have a long history of being consumed by humans. Bacillus subtilis is the organism responsible for the Japanese soybean-based condiment, natto, which has been consumed for more than 1,000 years.14

In the U.S. various species of Bacillus have been approved to produce familiar food-grade enzymes.5 These enzyme preparations (many of which may contain all or portions of the entire culture medium, including the cells) have been approved as generally recognized as safe (GRAS), or as food additives. A partial list of these enzyme preparations and their Code of Federal Regulations citation appears below.

Traditional strains of Bacillus sp. are considered nonpathogenic and harmless by researchers on several continents. 9, 10, 13, 14 However, it is the responsibility of each probiotic formulator to chose appropriate strains with respect to safety and functionality from among the many considered food-grade. The Bacillus Genetic Stock Center, which is supported by the National Science Foundation maintains nearly 1,000 strains of Bacillus subtilis and tens of strains of other Bacillus species. According to an international group of researchers publishing in Applied and Environmental Microbiology, the real frontier in probiotic research seems to be directed towards choosing the right strain for the job and attempting to understand how Bacillus spores achieve their beneficial effect on the colonic microflora.11

As researchers learn more about how probiotics need to work synergistically, their focus has expanded to a new area, called spore probiotics. Spore formers may provide certain advantages when used in combination with non-spore forming probiotics, like Lactobacillus sp.

In nature Bacillus sp. are often found in conjunction with other probiotics as part of stable groups of bacteria called "consortia."12, 14 Consortia are assemblages of microorganisms, in which each organism benefits from the metabolic activities of others in the group. Such naturally occurring consortia are known to be quite stable during transfer from one culture to another, and to retain their functional integrity better than single organisms or combinations of single species of bacteria. 2, 16

During growth these naturally occurring consortia produce their own matrix that surrounds the living cells, helping to sustain and protect them.14 Additionally, consortia reach an ideal balance between their member species.2 This means that within a given culture, some organisms die back and others multiply, so that the functionality of the group as a whole is maintained.2

Bacilli spores are able to survive transit through the gut more easily than non-spore-formers, and some evidence suggests that these organisms protect and improve the growth of other members of their consortia, as they move down the gastrointestinal tract, possibly by secreting tiny amounts of the hydrogen peroxide destroying enzyme, catalase, along with specific antimicrobials. 6, 14, 21

Thus spore formers may serve as part of an "advance guard" for members of their consortia, such as various species of Lactobacilli. Additionally, like other probiotics, Bacilli contribute to health by communicating with the immune system. Researchers have shown that the spores, although not fully capable of growth and reproduction in the colon due to its anaerobic environment, may produce their effects through biochemical signaling mechanisms.12, 11

For instance, one study showed that they may exert an influence on lymph nodes, promoting local immunity. 10 Other studies have shown that antimicrobials secreted by Bacillus sp. were able to inhibit and eliminate resistant Staphylococcus aureus from the contents of the large intestine in patients with ulcerative colitis. 27

While this area remains the subject of active research, it is likely that humans consuming probiotics would receive the most benefit if the product they were consuming contained naturally occurring consortia. Bacteria within these consortia are already "team players", who function together to produce desirable health benefits, often multitasking to fight off bad bacteria or fungi on one hand, while interacting with the immune system, and the lining of the colon on the other.27

Products containing consortia allow consumers to take advantage of a system that has already been honed by nature. Unfortunately, these are not always easy to find. Body Biotics by Life Science Products, Inc. may well be the only probiotic supplement that is based on a natural consortium of soil-based organisms on the market today.

Bibliography

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About the Author

Lee B. Dexter is a technical consultant, specializing in the commercialization of new food, supplement, and feed ingredients, which are based on natural resources. Ms. Dexter frequently prepares regulatory submissions in support of microbiologically-based ingredients for review by the U.S. FDA. She is the recipient of a number of scientific awards from USDA, and was responsible for depositing over 600 previously undescribed bacteria in the Agricultural Research Service's world renowned Culture Collection, more than anyone since World War II. As a result of her work, she holds a number of patents based on the use of naturally occurring microbial consortia.