Microorganism Breeding Examples

Microorganism Breeding Examples

Microorganism breeding - Image 5391-72

By resistance (resistance) is understood the ability of a microorganism to transfer significantly higher concentrations of the drug than other microorganisms of a given strain (species), or to develop at such concentrations that exceed those achieved in a macroorganism with the introduction of antibiotics, sulfonamides and nitrofurans in therapeutic doses. Resistant strains of microorganisms occur when changes in the genome of a bacterial cell as a result of spontaneous mutations. The latter are not associated with the directed action of bacterial antibacterial drugs on the DNA, which play the role of only selective agents. In the process of selection, as a result of exposure to chemotherapeutic compounds, sensitive microorganisms die, and resistant microorganisms survive, multiply and spread in the environment. Acquired resistance is fixed and inherited by subsequent generations of bacteria. The rate of development and the degree of severity of resistance are associated with the species and even the strain of the pathogen. The most quickly and often resistance to antibacterial drugs occurs in staphylococci, Escherichia, mycoplasmas, protea, Pseudomonas aeruginosa. Resistant strains are relatively rare among pasteurellas, erysipelotrixes, clostridia, group A streptococci, anthrax and hemophilic shelves. The most common genetic basis for resistance is the presence of extrachromosomal drug resistance factors in bacteria – plasmids and transposons. Bacterial plasmid resistance plasmids associated with in the process of conjugation of cells, called R-factors. R resistance conjugation plasmids (conjugating) consist of two components – the RTF resistance transfer factor, which ensures the transfer of genetic information, and the r-factor, which is responsible for antibiotic resistance. In some cases, r-factors (non-conjugating plasmids) exist independently in bacterial cells. Interbacterial transfer of such r-factors can be carried out by …

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