Microbiology Chapter 12 - Antimicrobial Treatment

What is the goal of antimicrobial chemotherapy?

Destroy the infective agent without harming the host’s cells.

Where do most antibiotics come from?

Bacteria and fungi.

What are key features of an ideal drug?

Selective toxicity, microbial, noncrossosive, fast acting, and affordable

Prophylaxis…

using a drug to prevent imminent infection of a person at risk

Antimicrobials…

all antimicrobial drugs

Antibiotics…

all drugs that target bacteria only

Key difference between semisynthetic and synthetic drugs?

Synthetic drugs are completely man made while semi synthetic are only partially

What should you know before starting antimicrobial therapy/treatment?

the medical condition of patient, identification of microorganism and it's range of suspectibility to various drugs

It is KEY to ____ before prescribing drugs

identify the agent

What is the Kriby-Bauer test?

determines how susceptible bacteria are to antibiotics

What does the Kirby-Bauer test measure?

Zone of inhibition around antibiotic discs.

What is an antibiogram?

profile of antimicrobial sensitivity

What is the MIC (Minimum Inhibitory Concentration)?

lowest concentration of drug that inhibits visible bacterial growth

what do antibacterial drugs target?

cell wall

What is selective toxicity?

The drug kills microbes without harming human cells.

What are the five major targets of antimicrobial drugs?

Cell wall synthesis, DNA/RNA structure & function, Protein synthesis, Cell membrane, and Folic acid synthesis

What makes up penicillin?

thiazolidine ring, beta lactam ring, and a variable side chain

What is a broad-spectrum drug?

Effective against many types of microbes

What is a narrow-spectrum drug?

Targets a specific group

What 2 drugs inhibit cell wall synthesis?

Penicillins and cephalosporins

what class targets protein synthesis?

tetracyclines

what are new and improved versions of a drug called?

generations

why might we be running out of new drug versions?

because bacteria keeps evolving

What class targets DNA/RNA?

Fluoroquinolones

What class of drug targets the cell membrane?

Polymyxins

What is a synthetic example of folic acid synthesis inhibitors?

Sulfonamides

Why are fungal infections hard to treat?

Fungi are eukaryotic and similar to human cells

what do we use to treat fungal infections?

antimycotic drugs

what are some antimalari drugs?

chloroquine and primaquine

what can treat other protozoan infections?

metronidazole and amoebicide

what is an example of a anti-helminthic drug?

ivermectin

What are the 3 major actions of antivirals?

Block entry, Block replication/transcription, Block maturation of viral particles

what are some example of antiviral agents?

acyclovir (blocks dna synthesis), azidothymdine (blocks dna transcription), and interferons

Most common antimicrobial side effect?

Diarrhea

what is drug resistance?

microbes tolerating an amount of a drug that would usually be inhibitory

What is intrinsic resistance?

Natural resistance to antibiotics they produce

What is acquired resistance?

Gained through mutation or horizontal gene transfer.

how is drug resistance acquired?

spontaneous mutation

What is an R plasmid?

A plasmid that carries antibiotic resistance genes.

What contributes to resistance development?

Overprescription, misuse, global travel, and antibiotic use in livestock.

What are probiotics and fecal transplants used for?

To restore gut microbiota after antibiotic therapy.

What is a superinfection?

Overgrowth of normal flora-resistant microbes after antibiotics destroy competitors.

what is 80% of antibiotics given to in the US?

livestock

what is the key difference between probitics and prebiotics?

live microbes are used to improve microbes in probiotics while nutirients are used to increase growth in prebiotics