The bacteria basics Flashcards

1
Q

Peptidoglycan

A

repeating disaccharide base w aa side chains that are cross linked by the enzyme Transpeptidase (blocked by PCN)

  • Transpeptidase = “PCN-binding-protein”
  • Peptidoglycan cell walls allow bacteria to survive osmotic stres! Give PCNs, cephalosporins, or Vanco to take away this defense - bacteria would disintegrate in hypotonic solution.
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2
Q

Catalase+

A

You need PLACESS for your CATs

Pseudomonas
Listeria
Aspergillus
Candida
E.coli
Staph
Serratia
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3
Q

Obligate aerobes

A

Nagging Pests Must Breathe

Nocardia
Pseudomonas aeruginosa
Mycobacterium
Bacillus

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4
Q

Aerobe in burns wounds, diabetes, nosocomial pneumonia, Pneumonia in CF

A
Pseudomonas Aeruginosa
(obligate aerobe)
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5
Q

Capsule of D-glutamate (i.e. made of aa residues)

A

Bacillus anthracis

unique. Other capsules are made of sugar

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6
Q

Periplasm enzyme

A

Beta-lactamases

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7
Q

LPS

A

Gram-negative outer membrane
more inside: Lipid A (induces TNF and IL-1)
Outer: O-polysaccharide (antigen)

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8
Q

Gram + cell wall

A

Peptidoglycan (support) + Lipotechoic acid (induces TNF and IL-1)

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9
Q

Pilus/fimbria

A

Mediates adherence of bacteria to cell surface
Sex pilus: connect bacteria during conjugation
-Made of glycoprotein
-E.g. Meningococcal pili - responsible for epithelial attachment to nasopharynx**

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10
Q

Flagella

A

Motility

-made of protein

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11
Q

Spore

A

Resistant to dehydration, HEAT, chemicals

  • Keratin-like coat*, dipicolinic acid, peptidoglycan
  • Spores form when shortage of nutrients –> lie dormant for years
  • Kill w STEAM

Bacillus (aer) and Clostridium (anaer)
found in soil

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12
Q

Plasmid

A

DNA

contains genes for antibiotic resistance, enzymes, toxins

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13
Q

Glycoclayx

A

Mediates adherence to surface (like pilus) esp foreign ones (catheters!!!)
-made of polysaccharide (like pilus)

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14
Q

Obligate Anaerobes

A

Can’t Breathe Air

Clostridium
Bacteroides
Actinomyces

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15
Q

Do not gram stain well

A

These Rascals May Microscopically Lack Color

Treponema (too thin)
Rickettisa (intracellular)
Mycobacteria (high lipid)
Mycoplasma (no cell wall)
Legionella pneumophila (intracellular)
Chlamydia (intracellular, lacks muramic acid in cell wall)
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16
Q

Silver stain

A

Legionella, Helicobacter pyloria, Fugni (e.g. Pneumoncystis)

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17
Q

Dark-field microscopy and fluorescent AB staining

A

Treponema

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18
Q

Giemsa stain

A

Certain Bugs Really Try my Patience

Chlamydia
Borrelia
Rickettsia
Trypanosomes
Plasmodium
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19
Q

PAS stain (periodic acid-schiff)

A

PASs the SUGAR (glycogen)

Stain glycogen, mucopolysaccharides
-Use to diagnose Whipples (Tropheryma whipplei)

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20
Q

Ziehl-Neelsen (carbolfuchsin**) stain

A

Acid fast organisms (Nocardia, Mycobacterium)- stains mycolic acid

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21
Q

India ink stain

A

Capsule not taken up by stain –> see translucent halo around the cell. Used primarily to identify:
Cryptococcus neoformans

India –> mother theresa –> halo –> capsule –> Crypto

22
Q

Chocolate agar w factors V (NAD+) and X (Hematin)

A

H. influenzae

When child has the “flu” mom goes to V/five and X/dime store to get CHOCOLATE

23
Q

Thayer-martin (or VPN) SELECTIVE media: Vnacomycin, Polymyxin, Nystatin

A

N. gonorrhoeae

24
Q

Bordet-Gengou (potato) agar

A

B. pertussis

Bordet for BORDETella

25
Q

Tellurite plate, Loffler’s media

A

C. diptheriae

Loffffffffler (something stuck in your throat… like a pseudomembrane)

26
Q

Lowenstein-Jensen agar

A

M. tuberculosis

27
Q

Eaton’s agar

A

M. pneumoniae

Mycoplasma like us: We like to EAT, have no cell wall, have cholesterol in our membranes

28
Q

Pink colonies on MacConkey’s agar

A

Lactose-fermenting enterics (e.g. E. coli)

29
Q

Eosin-methylene blue (EMB) agar. Colons w metallic green sheen

A

E. coli

30
Q

Charcoal yeast extract agar buffered w cysteine and iron

A

Legionella

31
Q

Sabouraud’s agar

A

Fungi

Sab’s a FUN GUY!

32
Q

Obligate intracellular

A

Stay inside when it’s Really Cold
(steal ATP from the host cell)

Rickettsia
Chlamydia

33
Q

Facultative Intracellular

A

Some Nasty Bugs May Live FacultativeLY

Salmonella
Neisseria
Brucella
Mycobacterium
Listeria
Francisella
Legionella
Yersinia pestis
34
Q

Encapsulated organisms

positive Quelleng rxns (capsular “swelling”)

A

SHiNE SKiS
**The capsule prevents phagocytosis

Strep pneumo
H. influenza Type B
Neisseria meningitidies
E. coli

Salmonella
Klebsiella
Group B Strep

35
Q

Gram + Rods

A

Crappy Bacteria Can Make Logs

Clostridium
Bacillus
Corynebacterium
Mycobacterium* (acid fast)
Listeria
36
Q

Gram + Branching filamentous

A

+ brANchers

Actinomyces
Nocardia (weakly acid fast)

37
Q

Urease + bugs

A

CHuck norris hates PUNKSS

Cryptococcus
H. pylori
Proteus
Ureaplasma
Nocardia
Klebsiella
S. epidermidis
S. saprophyticus
38
Q

Pigment producing: yellow “sulfur” granules

composed of filaments of bacteria

A

Actinomyces israelii

yellow sand in israel

39
Q

Pigment producing: yellow pigment

A

S. aureus

aureus = gold

40
Q

Pigment producing: blue-green pigment (pyocyanin)

A
Pseudomonas aeruginosa
(aerug- is green)
41
Q

Pigment producing: red pigment

A

Serratia marcescens

(thing red maraschino cherries

42
Q

Protein A

A

Binds Fc portion of IgG - prevents opsonization and phagocytosis <– prevents complement activation
S. aureus

43
Q

IgA protease

A

Enzyme cleaves IgA - allows colonization of respiratory mucosa

(SHiN): Strep pneumo, H. influenza type b, Neisseria (both mening and gonoc)

44
Q

M protein

A

Helps prevent phagocytosis and complement activation

  • mediates bacterial adherence
  • Is the target for type-specific humoral-immunity
  • Group A streptococci
45
Q

ENDOTOXIN

A
Edema
Nitrous Oxide
DIC (activate tissue factor)
Outer membrane (LPS)
TNF --> hypotension, fever
O-antigen (on the outer part)
eXtremely heat stable (100C for 1 hr)
IL-1 --> fever
Neutrophil chemotaxis <-- C5b
46
Q

Lysogenic phage carries genes for these 5 bacterial toxins:

A

ABCDE

shigA like toxin
Botulinum toxin (certain strains)
Cholera toxin
Diptheria toxin
Erythrogenic toxin of Strep pyogenes
47
Q

Guidelines for prevention of catheter infxn

A
  • 1) Proper hand washing
  • 2) full barrier precautions during insertion of a central line
  • 3) Chlorhexidine for skin disinfection
  • 4) Avoidance of femoral insertion site
  • 5) Removal of catheter(s) when no longer needed

Most common pathogens: Coag neg staph, Staph aureus

48
Q

Transformation

A

Ability to take up naked DNA and incorporate into your own. A feature of many bacteria, but esp S. pneumo, H. flu type b, Neisseria (SHiN).

49
Q

Transduction

A

Transfer of genetic information between organisms by viral phages

  • Generalized: a packaging event - parts of the bacterial chr may be accidentally packed in with the viral phage
  • Specialized: an excision event. the phage gets incorporated into bacteria, but then poorly excised out such that some of the bacterial genome is take with the viral phage.
50
Q

Transposition

A

DNA pieces w legs! can “jump” from one location to another and transfer genes from plasmid to chr and vice versa. no DNA homoogy necessary for insertion of transposon (can happen btwn different speices).