Antibiotic resistance is the ability of a
microorganism to counteract the effects of an
antibiotic. Usually, a
protein or an
enzyme that is coded by a
gene conveys the resistance mechanism. Resistance genes can be exchanged between
bacteria of the same
species via
plasmids. If a bacterium carries several resistance genes, it is called multiresistant
?. Multiresistant bacteria are a danger, especially in hospital
?s, where multiresistances are favored by
natural selection due to the excessive use of antibiotics.