Biology Study Set: Q4 Week 5 Micro Terms & Definitions

What are some options to control infections?

- Antimicrobial drugs

- Induction of the immune response

- Improvement in Public health

What are antibiotic drugs used for?

Bacterial infections

What are antibiotics?

Substances produced natrually by microorganisms that kill other organisms

What are naturally occurring antibiotics?

Antibiotics produced by microorganisms such as bacteria and fungi

What are semisynthetic antibiotics?

Chemically altered antibiotics that are more effective, longer lasting, or easier to administer than natrually occurring antibiotics

What are synthetic antibiotics?

Antibiotics made in a lab

What is selectively toxic antimicrobial drugs?

This means that antimicrobial drugs selectively inhibit microorganisms but not human cells aka they damage only the cells we want them to not our own cells

What are three ways antibiotics target bacteria?

- Bacterial cell envelope

- Biosynthetic processes within bacteria

- Bacterial metabolism

T or F

Selective toxicity is achieved by targeting the structural and/or biochemical properties unique to bacteria.

True

What drugs target the inhibition of cell wall synthesis?

- B lactam antibiotics

- Vancomycin

- Bacitracin

What are some examples of B lactam antibiotics?

- Penicillins

- Cephalosporins

- Carbapenems

- Monobactams

What is the core of B lactam antibiotics?

B-lactam ring

What is responsible for antimicrobial activity in B lactam antibiotics?

B lactam ring

What mechanism do B lactams use to kill bacteria?

They impair the last stage of cell wall synthesis by interfereing with PBP (penicillin binding protein)

How do B lactam subclasses differ from one another?

They are different in their side chains and presence of other ring structures

How does Vancomycin work?

It binds to PBP binding site

What is the difference between B lactams and Vanomycin?

B lactams bind to PBP directly

Vanomycin binds to PBP binding site

What antibiotic classes inhibit the 30S ribosomal subunit?

- Aminoglycosides

- Tetracyclines

What antibiotic classes inhibit the 50S ribosomal subunit?

- Macrolines

- Chloramphenicol

- Lincosamides

- Oxazolidinones

What is folic acid essential for?

Synthesis of nucleotides and many amino acids

How do bacteria make folic acid?

They use PABA and other substrates to make folic acid

How do sulfonamides work?

They bind to the enzyme in bacteria that make Folic acid which inhibits the production of nucleic acids and kills the bacteria

What antibiotics inhibit nucleic acid synthesis?

- Quinolones

- Matronidazole

- Rifampin

How does quinolone inhibit nucleic acid synthesis?

Inhibits topoisomerases that regulate DNA coiling

How does metronidazole inhibit nucleic acid synthesis?

Disrupts energy metabolism in anaerobes by hindering the replication, transcription, and repair process of DNA

How does Rifampin work?

Inhibits bacterial RNA synthesis

What is an antibiotic spectrum?

The range of bacteria that an antibiotic agent inhibits or kills

How can antibiotics be described in terms of spectrum?

Narrow spectrum drugs - effective against few

Broad spectrum drugs - effective against many organisms

What is a disadvantage of broad spectrum antibiotics?

Can cause damage against host and secondary infections by transient pathogens

What does the diffusion susceptibility test test for?

This evaluates the antimicrobial efficancy of a drug and reveals which drug is most effective against a particular pathogen

What does the zone of inhibition tell us on a diffusion susceptibility test?

This tells us how effective a drug is.

Larger zone of inhibition, the more effective that drug is

What does MIC test determine?

The minimum concentration of antibiotic that will be able to suppress growth of a bacteria

What does MBC test determine?

The minimum concentration of antibiotic that will kill the bacteria

What determines if an antibiotic is bactericidal or bacteriostatic?

The ratio of MBC to MIC

ratio of ability to kill to the ability to arrest growth

Antibiotics that kill bacteria are called ______

bacteriocidal

Antibiotics that arrest growth in bacteria are called _______

bacteriostatic

What do bacteriostatic antibiotics rely on?

The host immunity to eradicate the non-multiplying bacteria

How do you perform a test to get MIC and MBC?

Antibiotic dilution test and agar growth test

What drug causes black hairy tongue?

Metronidazole

What are two ways that bacteria acquire resistiance?

- Mutation within the species

- Acquisition of a R plasmid via horizontal gene transfer

What are mechanisms that bacteria have to resist antibiotic drugs?

- Inactivation of the drug

- Altered uptake by efflux pump (pump out the drug)

-Modification of structural target of drug

What is an example of antibiotic resistance to B lactam drugs?

B lactamase enzyme that breaks down and deactivates B lactam drugs

What are 3 prescription uses for antimicrobial drugs?

- Prophylaxis

- Specific/definitive therapy

- Empirical/presumptive therapy