Antimicrobials Flashcards
(28 cards)
What are Narrow-Spectrum antibiotics?
Active against only a few species of microorganisms
These antibiotics are specific and target limited types of bacteria.
What are Broad-Spectrum antibiotics?
Active against a wide variety of microbes
Useful in treating infections caused by multiple types of bacteria.
What is Amphotericin B used for?
Used for life-threatening mycotic infections (systemic candida)
It is a cell membrane disruptor that increases cell membrane permeability.
What are the adverse effects of Amphotericin B?
- Extremely nephrotoxic
- Infusion reactions due to cytokine release
These effects necessitate careful monitoring during treatment.
What is Fluconazole’s mechanism of action?
Inhibits fungal cell wall synthesis
It may increase levels of other drugs metabolized by cytochrome P450.
What is Acyclovir used for?
Treatment of herpes simplex viruses and varicella-zoster virus
It inhibits viral replication by suppressing synthesis of viral DNA.
What are common adverse effects of Ganciclovir?
- Thrombocytopenia
- Neutropenia
Used to treat CMV and prevent deafness.
What are cell wall inhibitors?
- Penicillins
- Cephalosporins
They bind to proteins during bacterial multiplication or activate enzymes that disrupt the cell wall.
What is the significance of the beta-lactam ring in penicillins?
Helps them break down the cell wall of bacteria
It binds to penicillin binding proteins (PBPs) on the bacterial membrane.
What is a common combination of antibiotics to enhance bactericidal effects?
Ampicillin combined with gentamicin
This combination increases the effectiveness of treatment.
What is the risk associated with penicillin allergies?
If allergic to one penicillin, assumed allergic to all penicillins
Up to 10% of patients may also be allergic to cephalosporins.
What is vancomycin used for?
Serious infections like MRSA and C-Diff
It binds with precursors for cell wall biosynthesis and is active against gram-positive bacteria.
What are carbapenems?
Broad spectrum antimicrobials effective for anaerobic infections, staph aureus, and gram-negative infections
Includes drugs like imipenem, meropenem, and ertapenem.
What are aminoglycosides known for?
Active against aerobic gram-negative bacilli and are considered lethal
They are often combined with penicillin to enhance efficacy.
What is the mechanism of action of clindamycin?
Treats anaerobic infections, particularly in the GI tract
It does not penetrate the blood-brain barrier (BBB).
What type of infections are tetracyclines used for?
Broad spectrum, but not used much due to resistance and side effects
They can stain teeth and cause GI irritation.
What is metronidazole (Flagyl) effective against?
Anaerobic and protozoal infections
It interacts with DNA to cause cell death.
What is the role of nucleic acid synthesis inhibitors?
Inhibit synthesis of DNA or RNA by binding to nucleic acids or interacting with necessary enzymes
Examples include rifampin and fluoroquinolones.
What leads to acquired resistance in bacteria?
Bacteria alter their cell machinery and produce enzymes that confer resistance
This can result in loss of drug sensitivity or multidrug resistance.
What is conjugation in bacterial resistance?
Bacteria exchange resistance genes through extrachromosomal DNA transfer
This process is common among gram-negative organisms.
What is a gram stain used for?
To differentiate between gram-positive and gram-negative bacteria
Gram-positive appears purple while gram-negative appears red.
What are the components of common antibiotic regimens for early-onset sepsis?
Ampicillin + Gentamicin
These regimens target infections in newborns.
What do sensitivity reports indicate?
Susceptible, Intermediate, Resistant
MIC/MBC values are reported for dose adjustment.
What is the purpose of antibiotic combinations?
- Initial therapy for unknown infections
- Mixed infections
- Prevention of resistance
- Decreased toxicity
- Enhanced antibacterial action
Combining antibiotics can improve treatment outcomes.
