Part 1: Antimicrobial Drugs

Sulfonamides

• sulfa drugs

• first broad spectrum “magic bullet” capable of treating different types of bacterial infections

Sulfonamides are a…

• antimicrobial drug

Who first discovered penicillin?

• Alexander Fleming

  • noticed penicillium mold inhibit staphylococcus bacteria

What was the first true antibiotic that was used as a therapeutic?

Penicillin

Penicillin

• true antibiotic

• naturally occurring compound that kills microbes

What does penicillin kill?

• gram positive NOT gram negative bacteria

Who finalized and produced penicillin?

• Howard Florey

• Ernst Chain

Chemotherapeutic

• chemical used to treat a disease

Antimicrobial

• chemotherapeutic that kills/inhibits microbes

Antibiotic

• antimicrobial natural product or derivative

Semisyhthetic antibiotic

• modified derivative of a natural antibiotic

Penicillin

• natural mold product

• antibiotic

Sulfonamides

• antimicrobials

• NOT an antibiotic

Ampicillin

• synthetic modified derivative of penicillin

• semisynthetic antibiotic

Features of antimicrobials

• selectively toxic

• have a therapeutic index

What does selectively toxic mean?

• more toxic to pathogens than host cells

What is a therapeutic index

• difference between amount that is therapeutic vs toxic

• ex: bleach/ rifampicin both kill E.coli, but only one is therapeutic

Broad Spectrum

• targets a wide variety of bacteria

• useful in treat infections by more than one pathogen or where pathogen is not known

Narrow Spectrum

• targets a limited set of bacterial classes

  • ex: only gram negative

• may treat specific infection without killing off normal microbiome

What are the different antimicrobial drug spectrums?

• broad

• narrow

What is a superinfection

• treatment with a broad spectrum antibiotic kills off protective microbiome

• gives pathogens an opportunity to colonize the host

What is a primary example of a superinfection?

• Clostridium difficle (C.diff)

Closyridia difficile

• opportunistic spore forming pathogen

• healthy microbe normally keeps in suppressed

Dysbiosis

• imbalance in gut microbial community associated with disease

How do broad spectrum antibiotics effect C. difficile

• they kill off most of normal, healthy microbiome

• leaves way for pathogen to colonize the GI tract

How is C. difficile treated?

• fecal transplant

Fecal transplant

• from a healthy patient can restore the microbial balance and stop recurrent infection of C.diff

Antimicrobials can either be what?

• bactericidal

• bacteriostatic

Bacteriostatic Antimicrobials

• block bacterial growth but rely on the immune system to fight off the infection

Bactericidal Antibiotics

• needed in infections of immunocompromised individuals or in infections where immune cells cant access