MICROBIOLOGY - M.H. Serhiichuk - 2008

Class="center">Chapter 12. HUMAN USE OF MICROORGANISMS

Medicine

In medicine, microorganisms are used to manufacture Vaccines, create Probiotics, and produce diagnostic products.

Vaccine manufacturing. Vaccines are biological preparations designed to establish active specific protective Immunity within the body. Modern vaccines are categorized into the following types:

- live vaccines - formulated from living microorganisms with reduced pathogenicity (attenuated microorganisms). For instance, the BCG vaccine strain is used for tuberculosis Prevention;

- inactivated vaccines - developed using pathogens previously inactivated through chemical or physical Methods. These are used to prevent pertussis, typhoid fever, and measles;

- subunit/chemical vaccines - specific compositions of antigenic Materials derived from a pathogen or culture medium, such as diphtheria or tetanus toxoid;

- conjugated vaccines - a type of chemical vaccine in which the antigenic material is covalently linked to an immunostimulatory carrier;

- synthetic vaccines - artificially synthesized macromolecular complexes with a defined Structure.

The initial stage of vaccine production involves the accumulation of microbial biomass or their metabolic products. This is followed by inactivation, the methods of which vary depending on the techniques employed. Subsequent steps include concentration, purification, and lyophilization. Mandatory quality control assessments evaluate the vaccine for sterility, antigenicity, immunogenicity, and several other properties.

Creation of probiotics. The manufacturing stages for probiotic preparations are largely identical, though nutrient media and cultivation conditions vary to match the physiological requirements of specific Bacteria.

Probiotic production parallels the technologies used for microbial biomass generation. It is mandatory to test the finished product for viable microorganism count, their activity, and the absence of contaminating microflora.

The most widely used probiotics are based on bifidobacteria, lactobacilli, Escherichia coli, or combinations thereof.

E. coli-based probiotics. Colibacterin is a dry preparation consisting of the lyophilized Escherichia coli strain M-17. This strain exhibits antagonistic activity against a broad spectrum of pathogenic and opportunistic microorganisms.

Biomass is produced on a casein medium containing gelatin at 37 ⁰C, with intensive aeration over 6–7 hours of cultivation. To the microbial suspension containing 4·10⁹ Cells/ml, 10% sucrose is added prior to lyophilization in specialized high-vacuum chambers. Mandatory quality controls include testing the product for sterility, viable Cell count, antagonistic activity against dysentery pathogens, and safety evaluation in laboratory animals. Escherichia coli has served as the basis for developing such preparations as Normoflorin, Coliflorin, Sevacol, and Mutaflor.

Bifidobacteria-based preparations. Commercial production of the domestic bifidobacteria-based preparation (Bifidumbacterin) began in 1971.

These preparations utilize cultures of Bifidobacterium adolescentis, B. animalis, B. bifidum, B. infantis, B. longum, and B. thermophilum. Biomass accumulation relies on Liver broth-based media supplemented with sodium chloride, peptone, and lactose. Culture lyophilization is conducted with The addition of a sucrose, gelatin, and skim milk mixture. Quality control of the final product is performed similarly to that of Colibacterin.

Lactobacillus-based preparations. Another prominent group of microorganisms utilized in a vast array of probiotics is lactobacilli. Lactobacilli-based probiotics contain: Lactobacillus plantarum, L. casei, L. amylovorus, L. lactis, L. acidophilus, L. delbrueckii subsp. bulgaricus, L. brevis, and others.

The cultures are grown on media based on milk hydrolysate, malt extract, or cabbage broth supplemented with 1.5% gelatin under agitation without aeration. Before lyophilization, sucrose, peptone, and skim milk are added to the bacterial suspension as stabilizers.

Preparations based on the genus Bacillus. The phenomenon of microbial antagonism has found widespread application in probiotic development. Aerobic spore-forming bacteria of the genus Bacillus exhibit particularly pronounced antagonistic properties.

The first reports on the medical and veterinary use of living Bacillus microorganisms emerged in France in the 1950s, following the discovery that the germination of B. subtilis spores produces several Enzymes capable of lysing the cells of staphylococci, Proteus, and certain other opportunistic and pathogenic bacteria.

In the 1970s, the Yugoslav association "Galenika" launched the commercial preparation Bactisubtil, recommended for individuals suffering from dysbiosis caused by Antibiotic therapy for INFECTIOUS DISEASES OF various etiologies.

Various biological preparations derived from bacilli are based on B. subtilis, B. cereus, B. polymyxa, B. coagulans, B. brevis, B. megaterium, B. pumilus, B. laterosporus, and B. licheniformis.

Biological preparations are sometimes supplemented with substances that stimulate the growth of probiotic cultures (such as sugars, Amino Acids, and Vitamins). These substances are referred to as synbiotics.

Obtaining modern diagnostic preparations. For rapid Diagnosis of infectious agents, enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assays are often used, which are based on the application of highly specific Antibodies to specific microbial Antigens. Modern biotechnology creates artificial antigens that fully reproduce The structure of natural Proteins and are used as components of diagnostic systems. Artificial antigens are naturally chemically modified compounds or completely synthetically produced ones.