Bacte antimicrobial Flashcards
Substances that kill or inhibit the growth of microorganisms
antimicrobial agents
Includes antibacterial, antifungal, antiparasitic, and antiviral agents.
What is the difference between bacteriostatic and bactericidal agents?
Bacteriostatic agents inhibit bacterial growth, while bactericidal agents kill the organism
Examples: Bacteriostatic - Chloramphenicol, Erythromycin; Bactericidal - Aminoglycosides, Beta-Lactams.
Innate characteristics of the organism that confer resistance to antimicrobial agents
intrinsic resistance
Transmitted to progeny vertically (inherited).
Resistance caused by changes in the usual genetic makeup of a microorganism
acquired resistance
Includes gene changes acquired via gene exchange.
List the intrinsic mechanisms of resistance. (4)
- Lack of affinity of the drug for the bacterial target
- Inability of the drug to enter the bacterial cell
- Removal of the drug by efflux pumps
- Innate production of enzymes that inactivate the drug
What are the basic steps required for antimicrobial activity? (6) AASITG
- Active drug
- Anatomic approximation
- Surface binding (adsorption)
- Intracellular uptake
- Target binding
- Growth inhibition or lysis and death
Name the mechanisms of antibiotic resistance. (4) TETE
- Tolerance
- Efflux
- Target site modification
- Enzymatic inactivation
A property of dormant, nongrowing bacteria (persisters) that allows them to avoid damage and survive in the context of antibiotic resistance?
tolerance
Drug targets are inactive in this state.
Transporter proteins that extrude toxic substances and antimicrobial agents from the cell
efflux pumps
Includes 5 major superfamilies such as Major Facilitator Superfamily (MFS) and ATP-binding Cassette (ABC) superfamily.
Sessile communities of microorganisms attached to a solid surface and embedded in an exopolysaccharide matrix
Biofilm
Involves stages like adhesion, maturation, and dispersion.
Fill in the blank: The _______ gene in Streptococcus pneumoniae gives acquired resistance to macrolides.
mefA
What are the steps involved in quorum sensing? (3) AMD
- Adhesion
- Maturation
- Dispersion
What is the role of beta-lactamases in antibiotic resistance?
Hydrolyze beta-lactam drugs, restricting access to drug targets
Includes mechanisms such as metallo-based and serine-based mechanisms.
What is the mecA gene responsible for?
Methicillin-resistant Staphylococcus aureus (MRSA)
It is an example of acquired resistance through modification of target sites.
True or False: Acquired resistance can occur through horizontal gene transfer.
True
