Bacterial Basics - structure, staining patterns, genetics Flashcards

1
Q

Gram staining challenges of mycobacteria

A

patchy - high lipid resists stain

cell wall of mycolic acid

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2
Q

gram staining challenges of mycoplasma

A

no cell wall - sterols for plasma membrane

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3
Q

gram staining challenges of treponema

A

gram -
corkscrew
need darkfield micro

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4
Q

gram staining challenges of Legionella pneumophila

A

branch chained fatty acids cell wall

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5
Q

Gram + vs Gram - cell walls

A

Gram +:
Lipoteichoic acids: contain lipids and telchoic acid, induces IL1 and TNFa
Thick peptidoglycan cell wall

Gram -:
Outer membrane - site of endotoxin (LPS), induces IL1, TNFa
Thin peptidoglycan layer w/in periplasmic space (site of b-lactamase)

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6
Q

Conjugation

A

pilus transfers DNA to another bacterium

“Conjugal visit”

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7
Q

Virulence factor

A

makes it stronger

capsule

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8
Q

Quellung reaction

A

anti-capsule serum added causes capsule swelling under microscope

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9
Q

Encapsulated bacteria

A

“Even Some Pretty Nasty Killers Have Shiny Bodies”

E coli
S. pneumo
Pseudomonas aeruginosa
Neisseria meningitidis
Haemophilus influenzae type B
Salmonella typhi
Group B strep
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10
Q

organisms causing sepsis and death in splenectomy patients w/ overwhelming infection

A
"SHiN"
Strep pneumo
Haemophilus
influenza
Neisseria meningitidis

Vaccines available
Capsules virulence factor

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11
Q

Glycocalyx

A

gelatonous, polysaccharide coating

aids attachment to foreign material - indwelling cathether

when organized and firmly adherent –> capsule

When loosely adherent and less organized –> slime/biofilm

  • resistent to abx
  • difficult to remove
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12
Q

Encapsulated yeast

A

cryptococcus neoformans

  • -> meningitis in AIDS
  • India ink stain
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13
Q

Prokaryote ribosomes

A

70S - 50S, 30S

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14
Q

Eukaryote ribosomes

A

80S - 60s, 40S

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15
Q

Plasmids

A

genetic material separate form DNA

carry genes for abx resistance or toxin production

transferred in conjugation

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16
Q

Transformation

A

lysed cell DNA taken up by living bacterium

incorporated into chromosomal DNA

17
Q

Transposons

A

small DNA segment that can self excise and relocate toa nother section of DNA or to a plasmid

can carry abx resistance or virulence factor

18
Q

Transduction

A

phage dependent
phage attaches to bacterium, injects its DNA

Some bacterial DNA can be packaged inside viral capsid
-released when bacteria ruptures –> new bacteria

19
Q

Pigment producing bacteria

A

S. aureus - large golden colonies

Actinomyces isreali - yellow (sulfur) granules

Pseudomonas aeruginosa - blue-green pigment

Serratia marcescens - red pigment

20
Q

Obligate anaerobes

A

clostridium sp
Actinomyces
Bacteroides

Use Metronidazole, clindamycin for anaerobes