Several molecular mechanisms of antibacterial resistance exist. Intrinsic antibacterial resistance may be part of the genetic makeup of bacterial strains. For example, an antibiotic target may be absent from the bacterial genome. Acquired resistance results from a mutation in the bacterial chromosome or the acquisition of extra-chromosomal DNA. Antibacterial-producing bacteria have evolved resistance mechanisms that have been shown to be similar to, and may have been transferred to, antibacterial-resistant strains. The spread of antibacterial resistance often occurs through vertical transmission of mutations during growth and by genetic recombination of DNA by horizontal genetic exchange. For instance, antibacterial resistance genes can be exchanged between different bacterial strains or species via plasmids that carry these resistance genes. Plasmids that carry several different resistance genes can confer resistance to multiple antibacterials. Cross-resistance to several antibacterials may also occur when a resistance mechanism encoded by a single gene conveys resistance to more than one antibacterial compound. COUNT 7
QSN1 What is part of hje the make up of bacterial strains? ANS1 Intrinsic antibacterial resistance QSN2 What is exchanged between between bacterial strains or species via plasmids that have this resistance? ANS2 antibacterial resistance genes QSN3 What can be absent from the bacterial genome? ANS3 antibiotic target QSN4 When does the spread of antibacterial resistance frequently occurs/ ANS4 vertical transmission QSN5 What does some resistance come from? ANS5 mutation QSN6 What method of spread can occur in antibacterial resistance? ANS6 vertical transmission of mutations QSN7 What do plasmids do in resistance? ANS7 carry several different resistance genes