Lecture Exam 4
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Where does Penicillin come from?
Fungi mold
Antibiotic
A chemical agent that kills/inhibits bacterial growth.
Who discovered Penicillin?
Alexander Fleming
Chemotherapeutic Index
Maximum dose tolerated by patient / Minimum dose that cures • Finds the dose of antibiotic that will target the pathogen and not harm the host. ⇈ Index : Targets pathogen (Safe) ⇊ Index : Can potentially kill patient (More dangerous)
Selective Toxicity
Selective toxicity refers to the ability of the drug to targets sites that are relative specific to the microorganism responsible for infection.
Broad Spectrum Antibiotic
Kills a large variety of microbes - Affects many gram positive and negative bacteria
Narrow Spectrum Antibiotic
Kills a very specific microbe - Either gram positive or gram negative
When are broad spectrum antibiotics prescribed?
When an illness cannot be identified.
Bacteriocidal
Kills bacteria
Bacteriostatic
Inhibits the growth of bacteria - Cell wall or other
Modes of Administration
Oral - Through the mouth, mmm yummy yummy • Ex: Pills, cough syrup, etc. Topical - Applied directly on the skin • Ex: Neosporin Parenteral - Injection • Ex: Vaccines, morphine drip
Antibiotic Modes of Action
⓵ Inhibiting cell wall synthesis ⓶ Disruption of cell membrane ⓷ Disruption of translation at ribosome ⓸ Interference with metabolism ⓹ Inhibiting DNA/RNA production
Inhibition of cell wall synthesis
Beta-lactams: (FUNGAL) - Destroy NAG/NAM chains and protein cross-links. Disadvantages: Allergies, Bacterial resistance ------------------- • Penicillin • Synthetic penicillin • Cephalosporins • Carbapenems
What is a solution to combat Penicillin resistant bacteria?
Synthetic versions - Side chains are added to decrease enzyme degradation. (Broader spectrum) - Serves as a “distraction”, bacteria attack additional chains rather than the drug itself. RISK: Can destroy natural flora
Beta-Lactam Resistant Bacteria
Beta-lactamase (penicillinase) - An enzyme created by bacteria that destroys beta-lactam rings. Drug becomes ineffective.
Why are extreme broad spectrum antibiotics dangerous?
These antibiotics can destroy normal flora.
Clavulanic Acid
Chemical group in synthetic penicillin. - Occupies penicillinase so the beta-lactam ring can work without being destroyed. Disadvantage: Creation of resistant bacteria
Synthetic / Semi-synthetic Penicillin
Risk: Broader spectrum, create bacterial resistance - Can be taken orally
What are Ethambutol and Isoniazid known to cure?
They are often used in combination to cure Tuberculosis.
What antibiotic is used to cure Legionnaire’s disease and atypical pneumonia?
Erythromycin (Macrolides)
Anti-viral Modes of Action
⓵ Block viral uncoating ⓶ Inhibit reverse transcriptase ⓷ Protease inhibitors ⓸ Cause mutations in DNA and RNA (Nucleoside analogs) ⓹ Inhibiting DNA/RNA production
Nucleoside Analogs
A fake nitrogenous base - Drug that mimics a base in DNA/RNA
What is an Upper Respiratory Infection?
An acute URI is a contagious infection of your upper respiratory tract. Your upper respiratory tract includes the nose, throat, pharynx, larynx, and bronchi.
Viral Infections of the Upper Respiratory Tract
Common cold - Caused by: Rhinoviruses (50%) Coronaviruses (20%) Adenoviruses