Control - Disease Organisms in Humans and Animals Flashcards
What are antimicrobial agents?
Chemical substances used to treat infectious disease
How did the history of chemotherapy originate and what did they first use it on?
Ehrlich came up with selective toxicity
-used it against syphilis spirochete
What was the first real antibiotic and who discovered it?
Penicillin (kills gram +) by Flemming
-other people collaborated to make it into a drug
What was the first successful antimicrobial agent?
Prontosil (red dye) Sulfa drug
-they can be toxic and not really used now
What are the 3 forms in which antimicrobial agents differ?
Synthetic Agent-Lab
Antibiotic-other organism
Semisynthetic Drug-Combo
What is selective toxicity?
Drug should harm pathogens but not the host
What is the different between toxic dose and therapeutic dose?
Toxic: drug concentration causes harm to host
Therapeutic: concentration eliminating pathogen but not the host
What is the goal when balancing the toxic and therapeutic doses?
To form the chemotherapeutic dose
Which antimicrobial drug covers the most bacteria?
Tetrcyclines
-Gram +/- , chlamydiae, rickets
What do synthetic antibacterial agents primarily inhibit?
DNA synthesis and cell wall formation
What does penicillin do to bacteria?
Interferes with cell wall (peptidoglycan) synthesis in rapidly growing cells causing the cell to burst
-prevent cross linking bridges between strands of polymers in peptidoglycan
What is the bacteria cell made of?
Peptidoglycan which contributes to strength and rigidity
What do beta lactic antibiotics have no effect on?
Bacteria that are not actively dividing
What happens when you’d develop an anaphylactic allergic reaction to penicillin?
Produces beta- lactamases that inactivate penicillin
What to polypeptide antibiotics affect?
Cell membranes
What is tetracyclines?
Broad spectrum antibiotics that target the attachment of tRNA to the 30S subunit
-destroy intestinal microbiota and cause staining of the teeth
What is Rifampin?
interferes with RNA synthesis
- effective against TB, leprosy, meningitis
- cause liver damage
What are antiprotozoals?
Agents to eradicate the parasite
Are heavy metals used as antimicrobials?
Yes, some help parasites mostly
How do you try and avoid drug resistance?
Find the lowest amount of agent that is needed to cause and effect of reducing the microorganism
What is the antibiotic sesceptibility test?
An agar disk diffusion method involves different antibiotics diffusing from paper disks on a bacterial confluent growth
How does antibiotic resistance come about ?
Mutations: Spontaneous changes in genetic material
Horizontal gene transfer: from donor cells
How can antibiotic resistance develop in cells
Altering metabolic pathways
Inactivating antibiotics
Reducing membrane permeability
Modifying the drug target
What is the antibiotic dilemma?
Antibiotics being available over the counter in developing countries allowing for improper use
