Bacterial Infections Flashcards
(141 cards)
Which cell wall is thick with lots of cross-linking?
Whose is thine with simple cross-linking?
Gram+
Gram-
How many layers does a Gram+ cell have?
What makes them up?
2 layers.
Outer layer is made of peptidoglycan, teichoic acid, polysaccharides and proteins (peptidoglycan cell wall).
The inner membrane is the cytoplasmic layer and it has proteins that may span the width of the lipid bilayer. It does NOT contain cholesterol.
How many layers does a Gram- cell have?
What makes them up?
3 layers.
It has the same 2 layers as Gram+, but also contains a thin outer layer that has LPS.
What is the periplasmic space?
What is the murein lipoprotein?
The periplasmic space is between the cytosolic layer and the cell wall of a Gram- cell. It contains proteins/enzymes.
Murein lipoprotein is between the cell wall and the outermost layer and helps bind the two together.
What molecule is a marker for Gram+ cells?
Teichoic acid
Which cells have porins?
Gram-
Which cells have a high lipid content?
Gram-
4 steps of performing a Gram stain
- Pour crystal violet onto slide and wait 60 s.
- Wash with water and flood w/ iodine. Wait 60 s.
- Wash with water and decolorize w/ 95% EtOH.
- Counter-stain w/ safranin. Wait 30 s. and wash.
What are the 6 most medically relevant Gram+ bacteria and their group?
Strips of cocci: Streptococcus
Clusters of cocci: Staphylococcus
Spore forming rods: Bacillus and Clostridium
Non-spore forming rods: Corynebacterium and Listeria
Which Gram- pathogen is spiral-shaped?
Spirochetes
What is a facultative anaerobe?
What is an obligate anaerobe?
FA - they are actually aerobes but can function anaerobically if needed.
OA - these cannot grow in an environment with oxygen.
Gram+ obligate aerobes (1)
Bacillus cereus
Gram+ facultative anaerobes (4)
Staphylococcus
Bacillus anthracis
Corynebacterium
Listeria
Gram+ microaerophilics (2)
Enterococcus
Streptococcus
Gram+ obligate anaerobes (1)
Clostridium
What is a microaerophilic bacteria?
It uses fermentation and has no ETC, but can function in places with low oxygen because they have SOD.
Gram- obligate aerobes (5)
Neisseria Pseudomonas Bordatella Legionella Brucella
Gram- microaerophilics (2)
Spirochetes (Treponema, Borrelia, Leptospira)
Campylobacter
What is the catalase reaction?
2H2O2 –> 2H2O + O2
Used to tell which cells are aerobic, anaerobic, etc.
What are examples of virulence factors?
Flagella
Pili
Capsules
What is the function of a pilus?
Adhesion. Without it, the bug in unable to infect as it cannot grab ahold of its host.
Most capsules are made of:
What is a major exception?
Simple sugar residues.
Bacillus anthracis - AA residues.
Why are encapsulated bugs more virulent?
Because neutrophils and Mo cannot phagocytose them.
What is the India ink stain?
Helps to determine if a bacteria has a capsule.
The capsule does not take up the stain and appears like a clear halo around the cell.
Used mostly on Cryptococcus.