Chap 24 - Antimicrobials Flashcards
Who originated the concept of selective toxicity?
Ehrlich originated the concept of selective toxicity.
What is selective toxicity?
The selective toxicity of antibiotics means that they must be highly effective against the microbe but have minimal or no toxicity to humans. “Harm the pathogen / not the host.”
Penicillium kills what kind of bacteria
Penicillium mold produces a substance that kills gram-positive bacteria.
What kind of “agents” are made in a pharmaceutical lab?
Synthetic Agents
These are products of or derived from the metabolism of living microorganisms?
Antibiotics
These are a new generation antimicrobials which are chemically modified antibiotics?
Semisynthetic drugs
_____is a dose of a drug is the concentration causing harm to the host.
Toxic Dose
______is referred to as the concentration eliminating pathogens in the host.
Therapeutic Dose
The toxic and therapeutic doses are used to formulate the ________.
Chemotherapeutic Index (Toxic / Therapeutic)
Drugs have a range of pathogens on which they will work, this is referred to as the ______.
Antimicrobial spectrum.
Synthetic Antibacterial Agents do what?
Inhibit DNA Synthesis and Cell Wall Formation
What are characteristics of Sulfanilamides?
- Target specific metabolic reactions. 2. Out compete essential folic acid components for binding sites in a bacterial enzyme. 3. Prevent nucleic acid synthesis and DNA replication.
Sulfanilamides are categorized as what kind of antibacterial agents?
Synthetic Agents
What are three common Synthetic Agents?
Sulfanilamides, Isoniazid, Quinolones.
Quinolones does what?
Blocks DNA synthesis in bacteria.
Isoniazid do what?
Interferes with cell wall synthesis in species of Mycobacterium by inhibiting the production of mycolic acid
Beta-Lactam Antibiotics do what?
Beta-Lactam Antibiotics Inhibit Bacterial Cell Wall Synthesis
How does Penicillin work?
Active against many gram-positive and some gram-negative bacteria. Interfere with cell wall synthesis in rapidly growing cells, causing the cell to burst.
Penicillin-resistant species produce _______ that inactivate penicillin?
Beta-lactamases
Name two broad spectrum beta-lactams
Ampicillin and Amoxacillin
What are broader spectrum semi-synthetic penicillins alternatives to penicillin?
Cephalosporins
What are monobactams active against?
Aerobic, gram-negative rods.
What is vancomycin effective against? And what are the side effects?
Gram-positive bacteria such as staphyococci. Side effects include damage to ears and kidneys.
Polypeptide antibiotics affect what?
The Cell membrane
Name two polypeptide antibiotics
Bacitracin, and Polymyxin
Which polypeptide antibiotic is only used topically because it is toxic?
Bacitracin
Tetracyclines are broad spectrum antibiotics that
target the attachment of ______.
tRNA to the 30S subunit.
What antibiotic causes “Gray baby” syndrome?
Chloramphenicol
Chloramphenicol is reserved for serious infections such as _______.
Meningitis, cholera, typhoid and typhus fevers, and rocky mountain spotted fevers.
Rifampin inhibits synthesis of what?
Nucleic Acid
Rifampin interferes with what?
RNA Synthesis
True or False - MRSA is a gram-positive bacteria?
True
What semisynthetic drug used against penicillin-resistant bacteria?
Clindamycin
List the ways antibiotic resistance can develop.
- Mutations 2. Horizontal Gene Transfer (T/T/C) 3. Altering metabolic pathways 4. Inactivating antibiotics 5. Reducing membrane permeability 6. modifying the drug targets.
A polyene used to treat Candida infections
Nystatin
Initial quartet of wonder drugs are:
Penicillin, streptomycin, chloramphenicol, and tetracycline.
