The photo above shows isolated bacteria from a camel.
Although associated with many diseases, microorganisms are similar to the proverbial two-edged sword. On the one side, pathogenic microorganisms cause diseases; on the other side, medicine is indebted and highly dependant upon therapeutics obtained from microorganisms. These therapeutics are mostly molecules such as antibiotics, but can also include whole live microorganisms such as the “probiotics”. The normal microbial communities of vertebrates help maintain health status and prevent infection by being the first line of defense.
The site-specific colonization by microbial communities on accessible surfaces: skin, oral cavity, upper respiratory tract, gastrointestinal tract, and vagina of healthy vertebrates occurs soon after birth. These communities of microbes are collectively known as the normal microflora or the indigenous microbiota. The microbiota is considered the first line of defense, having a great interest in the well-being of their homeland. The significance of the normal microbiota becomes very evident should infections arise as a consequence of its destruction or disruption. Broad-spectrum antibiotics are the most common cause of this disruption, and among the resulting diseases antibiotic-associated diarrhoea, and pseudomembranous colitis are the most common. In 1877, Pasteur and his associate Joubert, reported suppression of anthrax bacillus growth in co-cultures with ‘common bacilli’ (probably the gram-negative rods Escherichia coli), and concluded that “these facts perhaps justify the highest hopes for therapeutics”. By linking the two findings, the concept of bacteriotherapy or bacterial replacement therapy was conceived. Eli Metchinikoff supported the concept of bacteriotherapy by establishing a practice of regular ingestion of intestinal commensals (mainly lactobacilli) to confer health benefits to humans and various farmed animals.
The Lactic Acid Bacterial Industrial Platform (LABIP) hosted a workshop sponsored by the European Community to discuss probiotics. The Expert Committee issued a consensus definition of probiotics: ‘Oral probiotics are living microorganisms, which upon ingestion in certain numbers exert health benefits beyond inherent general nutrition’. According to the definition, probiotics may be consumed either as a food component or as a non-food preparation. The mode of administration should not necessarily be restricted to ingestion, but can include any mode of application of beneficial living microorganisms, and this should ideally be included in the definition. This definition does not clearly distinguish between probiotics and oral vaccination, since live orally-administered vaccines could be considered to fall within the criteria for probiotics. Therefore a more specific definition for probiotics might be: ‘Any living microorganism, which once delivered to the host at the appropriate time and location and in appropriate numbers can provide health benefits due to inherent characteristics of the microorganism and its interactions with the host, but not by the initiation of a specific host immune reaction’.
Probiotics are a heterogeneous group of microorganisms including both bacteria and fungi. The most commonly used probiotics are lactic acid bacteria such as lactobacilli, enterococci, streptococci and bifidobacteria. In addition to lactic acid bacteria, species from the Bacillus, Proprionibacterium and Escherichia genera are also in use as probiotics. The fungus most commonly used as a probiotic is Saccharomyces cerevisiae. Understanding what makes a microorganism a probiotic is debatable. However, a few general characteristics are proposed as prerequisites:
- Host origin is thought to be important. It is proposed that a probiotic to be used to enhance human or cattle health is best to initially have been of from human or cattle origin respectively. Host specific origin is not the case with all probiotics in current use e.g. S. cerevisiae (Boulardii) is a probiotic used to promote human health, yet is not of human origin.
- The microorganisms administered should be shown to be safe.
- The probiotic should be capable of transient or prolonged colonization.
- Potential probiotics need to have good biotechnological properties so that they can be cultured on a large scale, have an acceptable shelf life and in cases of oral administration (e.g. fermented dairy products) contribute to a good taste.
In my most recent work, Camel’s bacteria included some that exhibit great probiotic potentials.