Block 6 Review Flashcards Preview

Block 7 Microbiology > Block 6 Review > Flashcards

Flashcards in Block 6 Review Deck (19)
Loading flashcards...
1
Q

Virulence Encoded on Plasmids

A

= autonomous and replicate outside of the chromosome
“PASTE”
Pestis: Yersinia pestis adherence and invasion
Anthrax: pOX1 toxins, pOX2 capsule
Shigella: invasion
Tetani toxin
ETEC: adhesions and toxins and E. coli hemolysis
*often encode abx resistance too!

2
Q

Transposons

A

=insertion sequences flanking carious genes and recombinases/transposases

  • Step pyrogenes - exotoxins
  • Staph aureus - STSS
  • also responsible for bacterial resistance
3
Q

Pathogenicity Islands

A
=large regions of DNA usually found in tRNA operons 
H. pylori
UG E. coli 
EHEC 
EPEC
4
Q

Three types of resistance mechanisms

A

1) natural resistance
2) acquired resistance
3) mutational resistance

5
Q

Natural Resistance

A
  • gram-ve membrane - inaccessibility of target
  • multi-drug efflux pumps (TYPE 1)
  • drug inactivation (proteases)
6
Q

Acquired Resistance

A
  • plasmids/transposons
  • conjugation
  • target site modification (VRE)
  • efflux pumps (specific and non-specific)
  • drug inactivation/destruction (B-lactamases)
7
Q

Mutational Resistance

A
  • changes in the chromosome
  • target site modification (PBS changes)
  • metabolic bypass (TMP resistance)
  • de-repression of efflux pump
8
Q

Bacterial Energy Generation

A

1) Group Translocation - substrates (sugars) transported into cell by PTS (phosphotransferase system) and phosphorylated.
2) Glycolysis (NAD->NADH + H)
3) fermentation = alcohols or acids
or
4) respiration = TCA cycle and ETC

9
Q

Catalase and Superoxide Dismutase

A

protect bacteria from insult by radical oxygen species.

10
Q

Bacterial Growth

A

1) lag
2) log
3) stationary (nutrient limits slow growth, spore formation)
4) death phase
- impacts type of Abx rx and the effectiveness

11
Q

Bacterial Secretion Systems

A

1- ATP used, non-specific, pumps out abx
2- general secretory pathway, common
3- delivery of toxins to eukaryotic cells!!!
4- ATP-dependent transporter- important for transfer of DNA during conjugation.

12
Q

MIC

A

minimal inhibitory concentration- lowest abx needed to stop bacterial growth

13
Q

MBC

A

minimal bactericidal concentration- lowest abx concentration where no growth is seen after removal of abx.

14
Q

Disk diffusion assy

A

Kirby Bauer assay- provides clear zone based on concentration of abx gradient.

15
Q

Bacteriophage

A

Lysogenic (specialized) - integrate into chromosome
Lytic (generalized) - phage particles released by lysis of cell.
- Staph toxins
- C. dipheria toxin
- Strep pyogenes toxin
- EHEC shiga-like toxin
- V. Cholera toxin

16
Q

SCCmec

A

Staphylococcal chromosomal cassette

  • MRSA methicillin resistance
  • Type IV SSCmec encodes ACME gene that enhance MRSA’s colonization of the skin
17
Q

Urease (+)

A

HNCK

H.pylori
Nocardia
Crypotcoccus
Klebsiella

18
Q

ADP- ribosylating toxins

A
Diphtheria toxin (EF-2)
Pseudomona Exotoxin A (EF-2) 
ETEC Heat Labile Toxin (CAMP)
Cholera Toxin (CAMP)
Pertussis Toxin (CAMP)
19
Q

Transformation (naturally “competent”)

A

S.pneumonia
H.influenza
Nisseria