Microbial Pathogens Intro S3M1

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What are the medically important microbial groups
- Bacteria (prokaryotic)
- Viruses (non cellular)
- Fungi (Eukaryotic)
- Protozoa (Eukaryotic)
- Helminths (Eukaryotic)
Coccus

Sphere
Bacillus

Rod shape
Pleomorphic

More then one shape
Phage

Viruses infecting bacteria
Ribosomes in bacteria make them good drug targets, why

They are structurally different from humans containing 70S (30S and 50S) ribosomes
The capsid of a virus is formed by, and made up of
- Host cell derived
- Lipoprotein envelope
- Viral Glycoproteins
Ergosterol

Fungal membrane sterol
Hyphae

Filamentous cells of mold
Thermally dimorphic fungi

These fungi can convert to yeast form to filamentous form and back
Yeast

Single cell fungi that reproduce via budding
What are the classes of protozoans
- Amaeba
- Flagellates
- Ciliates
- Sporozoa
- (All are Unicellular)
What is the difference between PrP^Cand PrP^SC
- PrP^c are normal prions
- PrP^sc are infections prions
Prions cause what type of disease

Neurologic
Virulence

Quantitative ability of a microbe to cause disease
Virulence factor

Variety of microbial products/mechanisms that cause disease
What is a common opportunist found in hospitalized patients

Pseudomonas aeruginosa
Pathogen

Microbes that cause disease
Pathogenicity

Ability of an infectious agent to cause disease
Strict pathogens

Microbes that will always cause disease
Opportunistic pathogens

Only cause disease when something out of the ordinary happens
What are some examples of events that can cause opportunistic pathogens to harm the body
- Surgery
- Disrupted flora due to antibiotics
- Immune system deficiencies
Most human infections are caused by

Opportunistic infections
What are three important Opportunistic pathogens
- Staphylococcus aureus
- Escherichia coli
- Clostridium sp.
Mutualism

Benefit to both members
Commensalism

No apparent benefit or harm to either
What are some common entries for Staphylococcus aureus
- Skin & Resp. tract
- Causing cutaneous infections and endocarditis
What is believed to be the advantage of Probiotics

Prevention of diseases caused by opportunists by interfering with adhesion and enhancing the immune response
What microbes are most commonly used as probiotics
- Lactobacilli (rhamnosus, acidophilus)
- Bifidobacteria
- Saccharomyces (yeast)
What are some conditions that probiotics have shown to be successful for treating
- Diarrhea in children
- Prevention of C. difficile caused
- IBC
- Prevention of allergies in newborns
What are the steps of the infectious cycle
- Adhesion and colonization
- Invasion
- Replication
- Transmission (new host)
What are Koch's postulates
- Identify in all disease organisms)
- Isolate and grow in a pure culture
- Introduce into healthy model
- Reisolate from model and compare to original
What are the exceptions to the Koch postulates
- Not culturable
- Not universally disease causing
- Acquired virulence factors
- No animal model
- Polymicrobial disease
What is the molecular Koch postulates
- Identify: phenotype/gene in a pathogenic strains but not others
- Alter: Gene manipulation should alter virulence
- Restore: Gene recovery should restore virulence
What is the difference between gram positive and gram negative

Positive contains lipoteichcic acids protruding from a thick cell wall of peptidoglycan all overlying a bilayer plasma membrane

Negative has a very thin peptidoglycan layer found below an outer membrane with no lipoteichcic acid protruding from its surface
What are the steps to gram stains
- Heat Fixation
- Crystal violet
- Iodine
- Decolarization
- Counter stain safranin
What are the color differences following a gram stain between negative and positive
- G+ purple
- G- Red

Author

lancesadams

100329

Card Set

Microbial Pathogens Intro S3M1

Description

Micro

Updated

2011-09-07T19:37:08Z

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