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Micro Basic Flashcards

1
Q

Peptidoglycans
Composition
Function

A

Sugar backbone with peptide side chains cross linked by transpeptidase
Support. Protects against osmotic pressure

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2
Q

Lipoteichoic acid
Where is it?
What does it do?

A

Cell wall of Gram+

Induces TNF and IL1

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3
Q 
LPS
AKA
Location
What is it?
Components
A 
Endotoxin 
Outer membrane of Gram-
Major Surface Ag
Lipid A (induces TNF and IL1)
O polysaccharide is the antigen
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4
Q

Periplasm
What is it?
What kind of organisms
What does it contain

A

Space between cytoplasmic membrane outer membrane
Gram-
Hydrolytic enzymes include β lactamase

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5
Q

Capsule
Made from…
Function

A

Polysaccharides (except in Bacillus anthracis which contains D-glutamate)
Protects against phagocytosis

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6
Q

Pilus/Fimbria
Composition
Function

A

Glycoprotein

Mediates adherence of bacteria to cell surface. Sex pilus for conjugation

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7
Q

Flagellum
Composition
Function

A

Protein

Motility

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8
Q

Spore
Composition
Function

A

Keratin-like coat, Dipicolinic acid, Peptidoglycan

Resistance to heat, chemicals, dehydration

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9
Q

Glycocalyx
Composition
Function

A

Polysaccharide

Mediates adherence to surfaces (especially foreign surfaces)

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10
Q

Outer layer composition in Gram+ vs Gram- bacteria

A

+
Inside to outside:
Cytoplasmic membrane, Peptidoglycan (cell wall), Capsule
Pilus, Flagellum, Lipoteichoic acid (lipids + teichoic acids)
-:
Cytoplasmic membrane, Perplasm, Peptidoglycan, Endotoxin (LPS), Capsule
Pilus, Flagellum

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11
Q

Outer layers of Mycoplasma

A

Membrane contains sterols and have no cell walls

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12
Q

Cell wall of Mycobacteria

A

Contains mycolic acid with high lipid content

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13
Q

Bugs that do not gram stain?

A

“These Rascals May Microscopically Lack Color”

Treponema (too thin), Rickettsia (intracellular), Mycobacteria (high lipid content in cell wall), Mycoplasma (no cell wall), Legionella pneumophila (intracellular), Chlamydia (intracellular and lacks muramic acid in cell wall)

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14
Q

Giemsa Stains for what organisms

A

“Certain Bugs Really Try my Patience”

Chlamydia, Borrelia, Rickettsiae, Trypanosomes, Plasmodium

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15
Q

PAS
Name
What does it stain?
Use

A

Periodic Acid Schiff Base
“PASs the sugar”
Glycogen, Mucopolysaccharides
Diagnoses Whipple’s Disease (Tropheryma Whipplei)

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16
Q

Ziehl-Neelsen Stain
Name
Organisms

A

Carbol Fuchsin

Acid Fast organisms (Nocardia, Mycobacterium)

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17
Q

India Ink

A

Cryptococcus neoformans

Mucicarmine can also be used to stain thick polysaccharide capsule red

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18
Q

Silver Stain

A

Fungi, Legionella, Helicobacter pylori

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19
Q

Culture Requirements for H. influenzae

A

Chocolate agar with factor V (NAD) and X (hematin)

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20
Q

Culture Requirements for N gonorrhoeae and N meningitidis

A

Thayer-Martin (or VPN) media

Vancomycin (inhibits Gram+ organisms), Polymyxin (inhibit Gram- organisms except Neisseria), Nystatin (inhibits fungi)

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21
Q

Culture Requirements for B pertussis

A

“Bordet for Bordetella)

Bordet-Gengou (potato) agar

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22
Q

Culture Requirements for C diphtheriae

A

Tellurite plate, Loffler’s media

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23
Q

Culture Requirements for M tuberculosis

A

Lowenstein Jensen agar

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24
Q

Culture Requirements for M pneumoniae

A

Eton’s agar

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25
Culture Requirements for lactose fermenting enterics
Pink colonies on MacConkey's agar (fermentation produces acid, turning colonies pink) E coli is also grown on eosin-methylene blue (EMB) agar as colonies with green metallic sheen
26
Culture Requirements for Legionella
Charcoal yeast extract on agar buffered with cysteine and iron
27
Culture Requirements for Fungi
"Sab's a Fun Guy" | Sabouraud's agar
28
Obligate Aerobes
"Nagging Pests Must Breathe" | Nocardia, Pseudomonas aeruginosa (can use nitrates in anaerobic environment), Mycobacterium tuberculosis, and Bacillus
29
``` Obligate Anaerobes Name Weakness Gross Culture? What doe they produce? Where are they normally? What antibiotics don't work on them? ```
"Anaerobes Can't Breathe Air" Clostridium, Bacteroides, Actinomyces Lack Catalase and/or SOD and are thus susceptible to oxidative damage Foul smelling because of short chain fatty acids Difficult to culture Produce gas (CO2, H2) in tissue Normal GI flora Aminoglycosides ineffective because they need O2 to enter cell
30
Obligate intracellular bugs
"Stay inside when its Really Cold" Rickettsia, Chlamydia Can't make their own ATP
31
Facultative Intracellular bugs
"Some Nasty Bugs May Live FacultativeLY" | Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francissela, Legionella, Yersinia pestis
32
``` Encapsulated Bacteria Purpose of capsule Test Examples Who is especially at risk? ```
Antiphagocytic virulence factor that can serve as an antigen in vaccines Quellung Positive (Swelling = Swellung) "SHiNE SKiS" Streptococcus pneumoniae, Haemophilus influenzae B, Neisseria meningitidies, E coli, Salmonella, Klebsiella pneumoniae, group B Strep Asplenics. Give S pneumoniae, H influenzae, and N meningitidis vaccines
33
Catalase+ organisms Function of catalase Who is at risk? Examples
Degrades H2O2 before it can become microbicidal People with chronic granulomatous disease (NADPH oxidase deficiency) because they degrade the limited H2O2 "PLACESS for your CATs" Pseudomonas, Listeria, Aspergillus, Candida, E coli, S aureus, Serratia
34
Problem with polysaccharide capsule antigens? | How is ti solved?
``` T cells not activated because polysaccharides cannot be presented Conjugate to a protein to promote T cell activation and class switching ```
35
Pneumovax
Polysaccharide vaccine w/o conjugated protein against pneumococcus
36
Prevnar
Conjugated Polysaccharide vaccine against pneumococcus
37
H influenzae Type B Vaccine
Conjugated vaccine
38
Meningococcal Vaccine
Conjugated vaccine
39
Urease+ bugs
"CHuck norris hates PUNKSS" | Cryptococcus, H pylori, Proteus, Ureaplasma, Nocardia, Klebsiella, S epidermidis, S saprophyticus
40
Pigment producing bacteria
Actinomyces israelii - yellow sulfur granules (israel has yellow sand) S aureus - yellow pigment Pseudomonas aeruginosa - blue-green (like arugula) Serratia marcescens - red pigment (red maraschino cherries)
41
Protein A Function Organisms
Binds Fc of Ig to prevent opsonization and phagocytosis | S aureus
42
IgA protease Function Organisms Organ susceptible
Cleaves IgA "SHiN" S pneumoniae, H influenzae B, Neisseria Respiratory mucosa
43
M Protein Function Organisms
Prevents phagocytosis | GAS
44
``` Exotoxin Source Secreted from cells? Composition Location of gene Tox ```
``` Gram+ and Gram- Secreted from cells Polypeptide Plasmid or Bacteriophage Highly toxicity ```
45
``` Exotoxin Antigenicity Vaccines Stability Examples ```
Induces high titer Abs called antitoxins Toxoids used as vaccines Destroyed rapidly at 60 degrees (except for Staphylococcal enterotoxin) Tetanus, Botulism, Diphtheria
46
``` Endotoxin Source Secreted from cells? Composition Location of gene Tox ```
``` Outer cell membrane of most Gram- Not secreted Lipopolysacharide (structural part of bacteria released when lysed) Bacterial chromosome Low toxicity ```
47
``` Endotoxin Clinical effects MoA Antigenicity Vaccines Stability Examples ```
``` Fever, Shock Induces TNF and IL1 Poorly antigenic No toxoids formed and no vaccine available Staple at 100 degrees C for 1 hour Meningococcemia, Sepsis by Gram- rods ```
48
``` Corynebacterium diphtheriae Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Diphtheria toxin ADP ribosylating A-B toxin: Inactivates Elongation Factor (EF2) thus inhibiting protein synthesis Pharyngitis with pseudomembranes in throat and severe lymphadenopathy (bull neck)
49
``` Pseudomonas aeruginosa Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Exotoxin A ADP ribosylating A-B toxin: Inactivates Elongation Factor (EF2) thus inhibiting protein synthesis Host cell death
50
ADP ribosylating A-B toxin Names MoA
Diphtheria toxin, Exotoxin A, Heat Labile, Cholera toxin, Pertussis toxin B (binding) component binds host cell surface receptor enabling endocytosis; A (active) component attaches to ADP-ribosyl to disrupt host cell proteins
51
``` Shigella Spp Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Shiga Toxin (ST) Inactivates 60S ribosome by removing adenine from rRNA inhibiting protein synthesis GI mucosal damage --> dysentery. Enhances release of cytokines --> HUS
52
``` Enterohemorrhagic E coli (EHEC) Strain Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
``` O157:H7 Exotoxin Shiga-Like Toxin (SLT) Inactivates 60S ribosome by removing adenine from rRNA Enhances release of cytokines --> HUS Does not invade host cells ```
53
``` Enterotoxigenic E coli Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Heat-Labile Toxin (LT) and Heat-Stable Toxin (HS) HL (ADP ribosylating A-B toxin): Overactivates AC --> ↑cAMP --> ↑Cl secretion in gut and water efflux HS: Overactivates GC --> ↑cGMP --> ↓ resorption of NaCl and water in the gut Watery diarrhea "Labile in Air --> AC" "Stable in Ground --> GC"
54
``` Bacillus Anthracis Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Edema Factor Mimics AC and increases cAMP Responsible for characteristic edematous borders of black eschar in cutaneous anthrax
55
``` Vibrio cholerae Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Cholera toxin ADP ribosylating A-B toxin: Permanently activates Gs --> Overactivates AC --> ↑cAMP --> ↑Cl secretion in gut and water efflux Rice water diarrhea
56
``` Bordetella pertusis Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Pertussis toxin ADP ribosylating A-B toxin: Permanently inactivates Gi --> Overactivates AC --> ↑cAMP --> impaired phagocytosis to permit survival of microbe Whooping cough (coughs on expiration and whoops on inspiration 100 day cough in adults
57
``` Clostridium tetani Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Tetanospasmin Cleaves SNARE protein required for NT release of GABA and Gly neurons (Renshaw cells in spinal cord) Muscle rigidity, lock jaw, Risus sardonicus
58
``` Clostridium botulinum Kind of toxin produced? Name of toxin? MoA of toxin Manifestation Where do they get it from? ```
``` Exotoxin Botulinum toxin Cleaves SNARE protein required for NT release of ACh from neurons Flaccid paralysis, floppy baby Honey ```
59
``` Clostridium perfringens Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Alpha toxin (lecithinase) Phospholipase that degrades tissues and cell membranes Degradation of phospholipid C --> myonecrosis (gas gangrene) and hemolysis (double zone of hemolysis on blood agar)
60
``` Streptococcus Pyogenes Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Streptolysin O Degrades cell membranes Lyses RBCs (contributes to β hemolysis and host produces ASO used to diagnose RF)
61
``` Staphylococcus aureus Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Toxic Shock Syndrome Toxin (TSST1) Brings together MHCII and TCR to cause release of IFNγ and IL2 --> shock TSS: fever, rash, shock
62
``` Streptococcus pyogenes Kind of toxin produced? Name of toxin? MoA of toxin Manifestation ```
Exotoxin Exotoxin A Brings together MHCII and TCR to cause release of IFNγ and IL2 --> shock TSS: fever, rash, shock
63
Endotoxin Pathway of Action
LPS --> Macs --> IL1 (fever), TNF (fever hypotension), NO (hypotension) LPS --> complement --> C3a (hypotension, edema), C5a (neutrophil chemotactic) LPS --> tissue factor --> coagulation cascade --> DIC
64
Endotoxin Mnemonic
"ENDOTOXIN" | Edema, NO, DIC/Death, Outer membrane, TNFα, O Ag, eXtremely heat stable, IL1, Neutrophil chemotaxis
65
Bacterial Growth Curve
Lag: metabolic activity w/o division Log (exponential): Rapid cell division Stationary: Nutrient depletion slows growth. Spore formation in some bacteria Death: Prolonged nutrient depletion and buildup of waste products lead to death
66
Which antibiotics work on the log phase?
Cephalosporins and Penicillins becuase they act on peptidoglycan synthesis
67
Bacterial Transformation Mechanism Bacteria that can do it?
Take up DNA from surroundings "SHiN" S pneumoniae, H influenzae, Neisseria
68
Conjugation F+ x F- Hfr x F-
F+ x F-: dsDNA plasmid with genes for pilus | Hfr x F-: transfer of plasmid and chromosome genes after plasmid incorporation
69
Transposition
Segments of DNA jump from one location to another. Genes can be transferred from plasmid to chromosomes and vice versa Flanking DNA can be transferred as well
70
Transduction Generalized Specialized
Packaging event: Bacterial DNA packaged into lytic phage by accident Excision event: Flanking regions around bacterial DNA is put into a Lysogenic phage
71
Genes encoded in lysogenic phage
"ABCDE" shigA-like toxin Botulinum toxin, Cholera toxin, Diphtheria toxin, Erythrogenic toxin of Strep pyogenes

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