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62 Cards in this Set

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Cell wall biosynthesis is inhibited by antibiotics:

- which specific rxn is affected?
- which specific antibiotic does this?
- explain why/how this happens
The transpeptidation reaction is inhibited

Beta Lactam antibiotic

The Beta Lactam ring resembles the transition state of D-alanyl-D-alanine which occurs during transpeptidation.
List the components of LPS. x3

Which ones have negative charge
O-specific polysaccharide (neg)

Core polysaccharide (neg)

Lipase A
What is useful about the O-specific polysaccharide in LPS?

What happens when it is lost in pathogens?
Useful for serotyping b/c it varies among organisms.

Virulence decreases
What is the function of the core polysaccharide in LPS?

How do enteric bacteria make this useful?
Provides resistance to hydrophobic compounds.

Basis for resistance to bile salts.
Lipase A:

- components
- structural function
- why clinically important?
Saturated fatty acid

Provides rigidity

Toxic portion of LPS
LPS outer membrane:

- significance to antibiotics
- strengthened by?
- weakened by?
Excludes large molecules from passing through pores (such as vancomysin)

Divalent Calcium and Magnesium

EDTA
What is the outer layer of mycobacteria made of?

what does it mean clinically?
The outer layer of mycolic acid (lipid-like and waxy)

provides increased resistance to detergents, antibiotics, and other antibacterial agents.
Describe the cell envelope of Mycoplasmas. x4
No cell wall

No peptidoglycan

One membrane

Sterols in membrane
A lipid-rich cell wall in Mycobacteria results in? x4
1. Clumping

2. Acid Fastness

3. Resistance to detergents & PCN

4. SLOW growth
Mycobacteria and Mycoplasma:

- type of bacteria
- type of stain
related to gram positive

but does NOT stain positive
Complement-mediated killing of bacteria is effective (or not effective) against which type of bacteria?

why or why not.

Killing occurs how?
Gram NEGATIVE is susceptible

Killed by cell lysis via MAC
(Membrane Attack Complex)

Gram POSITIVE is naturally resistant

due to thick Peptidoglycan

Yet, gram positive is still opsonized by complements.
Capsules:

- AKA x2
- Composition (exception?)
Glycocalyx
Slime layer

Polysaccharides
(except for B. Anthracis - polypeptides)
Which two organisms are susceptible to vaccines using capsular material?
H. Influenzae type B

S. Pneumoniae
What is the antigen for flagella?
H-antigen
What powers Flagella?
PMF motor
List the movements of flagella. x3
Peritrichous - "run & tumble"

Polar reversible

Polar unidirectional
What allows for bacteria to transfer plasma during conjugation?
Sex pili
Pili adherence:

- attaches to what?
- strength
Mannose or other carbs on cell surface

Adherence increases under greater stress/resistance.
(chinese finger trap)
Endospores formed by what type of organism?
Some Gram Positive only
T/F - Antimicrobial handwashing agents are sporicidal.
False - they are not sporicidal
What acid is found in all endospores and what is its function?
Dipicolinic acid

Protect DNA
What are the three stages of Endospore germination?
Activation

Germination

Outgrowth
What 4 events will cause the endospore germination to be ACTIVATED?

What is required for germination activation? x2
Fresh medium
Change in T
Change in Age
Change in pH

Water
Triggering nutrient (e.g. - alanine)
During endospore germination, what gets excreted as the cortex swells? x2
Calcium

Dipicolinic acid
What events occur during endospore germination, outgrowth phase? x4
Core enlarges

mRNA synthesis begins

Spore coat ruptures

New PG formed via spore wall expansion
What is the composition of biofilm?
Polysaccharides

Multiple species of organisms
What causes dental caries?
Biofilms
How does biofilms provide protection. x2
Protects bacteria from antibiotics & being washed away

Protects hosts by blocking pathogens
What are the similarities between nucleoid and plasmids? x2

Differences? x2
Both are genetic elements
Both are circular

Nucleoid attached to inner membrane,
while plasmid do not.

Plasmids contain antibiotic resistance and virulence genes.
What are bacterial inclusion bodies?
Protein aggregates

(visible via microscopy)
Ribosomes:

- composition
- function
Proteins + RNA

mRNA translation
Clinical significance of bacterial ribosomes.
Good target for antibiotics
What is the basis of what causes the toxicity in applying antibiotics to bacterial ribosomes?
Mitochondria originated from bacteria.
Oxidase Test:

- Detects presence of what?
- Differentiates what?
Cytochrome C Oxidase

Pseudomonads from Enterobacteriae
Which organism is unique because its capsule is made of polyPEPTIDES?
B. anthracis
List 4 virulence factors associated with capsules
1. Anti-phagocytic

2. Poorly Immunogenic

3. Influences Adherence

4. Partial inhibition of MAC formation
The bacterial flagellum has a motor consisting of? x2
1. Mot complexes (stators)

2. C ring (rotors acting as a switch)
Bacteria usually moves towards Chemotaxis with what type of movement?
Alternating between "run" and "tumble"
List 3 other types of motility systems besides flagellum and pili.
1. Ratchet-based
(Flavobacterium)

2. Pilus-retraction
(Pseudomonas Aeruginoa)

3. Gliding motility
(requires contact with surface)
What is the name given to the model depicting Bacterial Adherence?
"shock absorber" model
Endospores are resistant to? x6
Antibiotics
Acids
Alcohols

Drying/Heat
Radiation

many chemical disinfectants
Endospores are sensitive to? x4
1. Glutaraldehyde

2. Steam

3. Peracetic acid

4. Hypochlorite
Endospore components. x5
Core

Spore wall

Cortex

Spore coat

Exosporum
Which endospore layer is thickest?
Cortex
Describe the Endospore Core
Genome

Protein synthesis machinary
Describe the Endospore Spore Wall
Contains Peptidoglycan
Describe the Endospore Cortex
Concentric layers
of
spore-specific
PG
Describe the Endospore Spore Coat
Keratin-like protein coat

Disulfide bonds ample
Describe the Endospore Exosporum
Remnants of mother cell membranes
What is found in all endospores and helps protect DNA
Dipicolinic acid
Which stage of Endospore germination would you see a loss of temperature resistance?

- Activation
- Germination
- Outgrowth
Germination
Biofilms form on what 3 likely places?
1. Solid substances in contact w/ moisture

2. Soft tissue surfaces in living organisms

3. Devices at liquid-air Interfaces
(catheters & implant devices)
List the major Internal structures for bacteria. x5
Nucleoid

Ribosomes

Inclusion bodies

Plasmids

Storage granules
List 3 types of Storage granules associated with bacteria.
1. Carbon storage polymers (PHB)

2. Polyphosphate

3. Suflur granules
What bacterial internal structure is composed of aggregated proteins and visible under a microscope?
Inclusion bodies
What 5 things should clinicians know regarding PLASMIDS?
1. Most current antibiotics produced by bacteria/fungi (thus resistant genes already exist)

2. Widespread use increases plasmids containing resistance genes

3. Natural competent bacteria are many

4. Transference of plasmids can occur among bacteria of differing species

5. Virulent only with a virulence plasmid in SOME bacterial species
Bacterial ribosomes are responsible for?
mRNA translation
Large subunit of Bacterial Ribosomes can be treated with?
Macrolides
(erythromycin, azithromycin)

Clindamycin

Chloramphenical
Small subunit of Bacterial Ribosomes can be treated with?
Tetracycline

Streptomycin
Large subunit of Bacterial Ribosomes has how many proteins?
31 proteins

in 50S
Small subunit of Bacterial Ribosomes has how many proteins?
21 proteins

in 30S
Presence or absence of Cytochrome Oxidase impacts treatment plan how?
NO impact on

- Antibiotic choice
- Treatment decisions