Microbiology antibiotic resistance
Good evening everyone! What molecular mechanisms might underlie antibiotic resistance?
Hey! antibiotic resistance can be explained, for example, by the presence of plasmids in bacterial cells. Plasmid is an extrachromosomal circular DNA with a limited set of genes; plasmid genes are not vital to the cell, but can provide additional benefits. In particular, the plasmid can contain genes that confer antibiotic resistance. The plasmid gene can encode an enzyme capable of cleaving a chemical bond in the antibiotic structure. For example, beta-lactamase cleaves the beta-lactam ring of penicillin and its derivatives
Interestingly, bacteria somehow find ways to uncouple antibiotics, the structure of which is very far from natural, for example, fluoroquinolones
@argentum but I haven't said that the presence of plasmids is the only mechanism by which bacteria resistance to antibiotics can be explained. I am not an expert in biochemistry, so I wrote only about the mechanism that I knew about
What other mechanisms are there for the acquisition of antibiotic resistance in bacteria?
Several bacteria of different species, fungi and other microorganisms can combine to form biological films. They look like a city of multi-story buildings, with different types of microorganisms living on each floor. On top, the biofilms are covered by a thick layer of mucus that prevents antibiotics from penetrating. Different types of microorganisms inside the biofilm perform different functions, for example, someone provides a neighbor with energy, another helps to destroy antibiotic molecules using secreted enzymes, the third teaches them to be more aggressive and more pathogenic.
@aleksandr-ialkaev sounds very interesting! which species of bacteria can form such films?
@marie-curie, all species of bacteria can form biofilms, for example E. coli, S. aureus, P. aeruginosa, K. pneumonia, Salmonella spp., Serratia marcescens, Shigella flexneri, Burkholderia cepacia, Acinetobacter baumannii, Mycobacterium tuberculosis, etc.
@nanochimik47, biofilms form very often. Biofilms are an example of the simplest ecosystem. They started to form about 3.25 billion years ago. They are formed in any ecological niches: intestinal microbiome, lake surface, tubercules of nitrogen-fixing plants, urinary catheter. Bacteria can also exist in the form of planktonic forms, but if the habitat conditions become unfavorable, then it is easier for them to survive as part of the biofilm. For example, under the action of antibiotics, inside a volcano, in hot geysers.