Antibiotics: an ongoing war (part 2)
The word ‘antibiotic’ refers to a substance produced and released by microbes (including fungi) that kills or inhibits the growth of sensitive bacteria. These molecules have been manipulated highly in the lab to increase efficacy and selectivity.
But what are bacteria?
They are tiny microorganisms (often about a few micrometers, id est 10-6 meters) defined as prokaryotes. Prokaryotes are organisms made by a single cell without a nucleus, with just a cellular wall and a cell membrane, containing some genetic material, together with a few molecules called enzymes, which allow the cell to develop a metabolism.
Bacteria are ubiquitous: they can live in every kind of environment. Different species have adapted to live in different environments. The majority of bacteria are harmless to humans. However, given their numerosity, the dangerous ones are still many.
In medicine, bacteria are categorized using Gram staining, a colorimetric method to highlight different molecules. For this lab technique, observing a microscopic sample is needed. The sample needs to be processed using specific dyes, among which crystal violet is the main. The difference between Gram-positive and Gram-negative bacteria is mainly about membrane composition: the first ones have just one cell membrane and one thick cellular wall, whereas the second ones have two membranes but a thin cellular wall.
Unlike viruses (that we certainly have all heard of in the last few years), bacteria do not need to infect a cell to survive, but they complete their life cycle in the environment autonomously, thus in the human body, too.