Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
126 Cards in this Set
- Front
- Back
|
What's on the outside of Gram-Positives?
|
Gram-positive: Cell wall/Cell membrane w/ a big chunk of peptidoglycan for support. Also has Teichoic Acid
|
|
|
What does Teichoic Acid induce?
|
TNF and IL-1
|
|
|
What's on the outside of Gram-Negatives?
|
An outer membrane made of Endotoxin/LPS
And a smaller chunk of peptidoglycan |
|
|
What are the antigens of the outer surface of gram pos and neg?
|
GP: cell wall/membrane
GN: Polysaccharide |
|
|
Who induces TNF and IL-1 in Gram Negatives?
|
Lipid A
|
|
|
What is the periplasm? where is it? what does it contain?
|
It is the space between cytoplasmic membrane and outer membrane in gram-negatives. Contains hydrolytic enzymes like B-Lactamases
|
|
|
Fxn of Capsule?
|
Protect against phagocytosis
|
|
|
Make-up of capsule?
|
Polysaccharide except in Bacillus anthracis which is made of D-Glutamate
|
|
|
Make up and Fxn of Pilus/Fimbria?
|
Mediate adherence.
Sex pilus forms for conjugation Made of Glycoprotein |
|
|
What is a spore coat made of?
|
Keratin-like dipicolinic acid
|
|
|
What is a Glycocalyx? make up?
|
Polysac that mediates adherence to surfaces, esp foreign ones like catheters
|
|
|
Different Bacterial Morphologies?
|
Circular (cocci)
Rod (bacillus) Branching Filamentous Pleomorphic Spiral No Cell Wall |
|
|
Who are the different gram pos and neg COCCI bacteria i need to know?
|
Gram Positive:
Staph Strep Gram Neg: Neisseria |
|
|
Who are the different gram pos BACCILUS bacteria i need to know?
|
GRAM POS:
Clostridium Corynebacterium Bacillus Listeria Mycobacterium (acid fast) |
|
|
who are the different gram negative BACCILI bacteria i need to know?
|
Enterics
Haemophilus Legionella (silver) Bordetella Yersinia Francisella Brucella Pasteurella Bartonella Gardnerella (gram variable) |
|
|
Who are the Gram Negative Enterics (Rods)?
|
E.coli
Shigella Salmonella Yersinia Klebsiella Proteus Enterobacter Serratia Vibrio Campylobacter Helicobacter Pseudomonas Bacteriodes |
|
|
Who are the branching filamentous bacteria?
|
Gram Positive:
Actinomyces Nocardia (weakly acid fast) |
|
|
Who are the pleomorphic bacteria?
|
Gram negative:
Rickettsiae Chlamydiae (giemsa) |
|
|
Who are the spiral bacteria?
|
SPIROCHETES
Leptospira Borrelia (giemsa) Treponema |
|
|
Who are the no cell wall bacteria?
|
Mycoplasma
|
|
|
Who are the bacteria who have special stains and what are their stains?
|
Mycobacterium (acid fast)
Nocardia (weakly acid fast) Legionella (silver) Chlamydiae (giemsa) Borrelia (giemsa) |
|
|
Who are the bacteria w/ unusual cell walls/membranes?
|
Mycoplasma: no wall, but contain sterols
Mycobacteria: Contain mycolic acid and have a high lipid content |
|
|
Mnemonic for Bacteria that don't gram stain well?
|
These Rascals May Microscopically Lack Color
Treponema (too thin) Rickettsia (intracellular) Mycobacteria (high lipid content requires acid fast) Mycoplasma (no wall) Legionella pneumophila (intracellular) Chlamydia (intracellular |
|
|
So how can visualize and gram stain Treponema?
|
Darkfield microscopy and fluorescent antibody staining
|
|
|
5 stains we need to know and what they're used for?
|
Giemsa: borrelia, plasmodium, trypanosomes, chlamydia
PAS: stains glycogens, mucopolysacs, Dx's Whipple's disease Ziehl-Neelsen: acid fast bacteria India Ink: Cryptococcus neoformans Silver: fungi, legionella |
|
|
SPECIAL CULTURE REQUIREMENTS
H. influenzae? |
Chocolate Agar w/ factors V and X
|
|
|
SPECIAL CULTURE REQUIREMENTS
N. gonorrhoeae? |
Thayer-Martin media
|
|
|
SPECIAL CULTURE REQUIREMENTS
B. pertussis? |
Bordet-Gengou (potato) agar
|
|
|
SPECIAL CULTURE REQUIREMENTS
C. diphtheriae? |
Tellurite plate, Loeffler's Media
|
|
|
SPECIAL CULTURE REQUIREMENTS
M. tuberculosis? |
Lowenstein-Jensen agar
|
|
|
SPECIAL CULTURE REQUIREMENTS
M. pneumoniae? |
Eaton's agar
|
|
|
SPECIAL CULTURE REQUIREMENTS
E.coli? |
Eosin-methylene blue (EMB) agar
blue-black colonies w/ metallic sheen |
|
|
SPECIAL CULTURE REQUIREMENTS
Lactose-fermenting enterics |
Pink colonies on MacConkey's agar
|
|
|
SPECIAL CULTURE REQUIREMENTS
Legionella? |
Charcoal yeast extract agar buffered w/ iron and cysteine
geez |
|
|
SPECIAL CULTURE REQUIREMENTS
Fungi? |
Sabouraud's agar
|
|
|
Who are the obligate Aerobes?
|
Nocardia
Pseudomonas AERuginosa Mycobacterium tuberculosis Bacillus M. tb is so obligate that it heads for the apices of the lungs cause of they have the highest PO2 |
|
|
So were do we come across the obligate aerobes mostly?
|
burn wounds
nosocomial pneumonia pneumonias in CF pts |
|
|
Who are the main obligate anaerobes?
|
Clostridium
Bacteroides Actinomyces |
|
|
Why are they anaerobic?
|
They lack catalase and/or superoxide dismutase--->susceptible to oxidative damage.
|
|
|
General characteristics of obligate anaerobes?
|
Foul Odor (short chain FA's)
Difficult to culture Produce gas in tissue (CO2, H2) |
|
|
Which class of drugs are useless against anaerobes? why?
|
Aminoglycosides
they require O2 in order to enter the bacterial cell |
|
|
Who are the obligate intracellular Bacteria?
|
Rickettsia
Chlamydia they can't make their own ATP |
|
|
Who are the facultative intracellular bugs?
|
Salmonella
Neisseria Brucella Mycobacterium Listeria Francisella Legionella Yersinia |
|
|
How do you test to see if a bacteria has a capsule?
|
Quellung Test
if encapsulated it will swell when anticapsular antisera is added |
|
|
Who are some major examples of encapsulated bacteria?
|
Strep pneumoniae
Neisseria meningitidis Haemophilus influenzae (esp B type) Klebsiella pneumoniae |
|
|
Capsule and relationship to vaccines?
|
Capsule serves as the Ag for vaccines.
Conjugation w/ protein inc immunogenicity and T-Cell-Dependent response |
|
|
Who are the Urease-Positive Bugs?
|
Proteus
Klebsiella H. pylori Ureaplasma Particular Kinds Have Urease |
|
|
Pigment producing bacteria?
|
S.aureus = yellow
P. aeruginosa = blue/green Serratia marcescens = red |
|
|
What are three Bacterial virulence factors and their fxns?
|
S. aureus protein A = bind Fc of Ig disrupting opsonization and phag.
IgA protease = cleaves IgA Group A Strep M Protein = prevents phag |
|
|
Who has IgA protease?
|
S. pneumoniae
H. influenzae Neisseria |
|
|
EXOTOXINS vs ENDOTOXINS
Source? |
Exo: some gram pos and neg's
Endo: outer cell membrane of most gram neg's and Listeria |
|
|
EXOTOXINS vs ENDOTOXINS
secreted from cell? |
exo: yes
eno: no |
|
|
EXOTOXINS vs ENDOTOXINS
chemistry? |
exo: polypeptide
endo: Lipopolysaccharide (structural component that is released upon lysis) |
|
|
EXOTOXINS vs ENDOTOXINS
Location of genes? |
exo: plasmid or bacteriophage
endo: bacterial chromosome |
|
|
EXOTOXINS vs ENDOTOXINS
Toxicity? |
exo: HIGH (fatal at 1 microgram)
endo: low (fatal at 100's of micrograms) |
|
|
EXOTOXINS vs ENDOTOXINS
clinical effects? |
exo: various
endo: Fever, Shock |
|
|
EXOTOXINS vs ENDOTOXINS
Mode of action? |
exo: various
endo: Includes TNF and IL-1 |
|
|
EXOTOXINS vs ENDOTOXINS
Antigenicity? |
exo: induces high-titer Ab's called antitoxins
endo: poorly antigenic |
|
|
EXOTOXINS vs ENDOTOXINS
heat stability? |
exo: destroyed rapidly at 60 celsius (except staphylococcal enterotoxin)
endo: stabile at 100C for 1 hr |
|
|
EXOTOXINS vs ENDOTOXINS
Typical Diseases? |
Exo: Tetanus, Botulism, Diphtheria
Endo: Meningococcemia, spesis by gram-neg rods |
|
|
Two main types of Exotoxins?
|
Superantigens
ADP Ribosylating A-B toxins |
|
|
MOA of SuperAg's?
|
binds directly to MCH II and TCR simultaneously--> activation of large numbers of T-cells--->release of IFN-y and IL-2
|
|
|
MOA for ADP Ribosylating A-B toxins?
|
B (binding) component binds to receptor on surface of host cell--->endocytosis
A (active) component attaches an ADP-ribosyl to host cell protein--->altered protein fxn |
|
|
Who has a superantigen exotoxin?
|
S. aureus
S. pyogenes |
|
|
What superantigen exotoxin does S. aureus have? fxn?
|
TSST-1 which causes Toxic Shock Syndrome
S.aureus also has endotoxins that can lead to food poisoning and staphylococcal scaled skin syndrome |
|
|
Sx's of toxic shock syndrome?
|
Fever
Rash Shock |
|
|
What SuperAg Exotoxin does S. pyogenes have?
|
Erythrogenic toxin --> scarlet fever and a toxic shock-like syndrome
|
|
|
Which bacteria have ADP Ribosylating A-B toxins?
|
Corynebacterium diphtheriae
Vibrio cholerae E.coli Bordetella pertussis |
|
|
What does C. diphtheriae's exotoxin do?
|
inactivates elongation factor 2 (EF-2)-->pharyngitis and pseudomembrane in throat
|
|
|
What does vibrio cholerae's exotoxin do?
|
ADP Ribosylates G-protein---> stimulates adenylyl cyclase--->inc pumping of Cl into gut and dec Na absorption--->voluminous rice-water diarrhea
|
|
|
What does E.coli's exotoxin do?
|
Heat-labile toxin stimulates adenylate cyclase
Heat-stabile toxin stimulates Guanylate cyclase. Both cause watery diarrhea |
|
|
What does Bordetella pertussis' exotoxin do?
|
Inc cAMP by inhibiting G-alpha-i--->whooping cough
Inhibits chemokine receptor--->lympocytosis |
|
|
Who else has exotoxins that don't fall into the superAg or ADP-ribosylating categories?
|
Clostridium perfringens
C. tetani C. botulinum Bacillus anthracis Shigella S. pyogenes |
|
|
What does Clostridium perfringens' exotoxin do?
|
alpha toxin causes gas-gangrene
|
|
|
what does C. tetani's exotoxin do?
|
Blocks the release of inhibitory neurotransmitter GABA and glycine--->lockjaw
|
|
|
what does C. botulinum's exotoxin do?
|
Blocks the release of ACh--->anticholinergic sx's, CNS paralysis (esp CN's), causes floppy baby
|
|
|
what does Bacillus anthracis' exotoxin do?
|
Edema factor, part of the toxin complex, is an adenylate cyclase
|
|
|
what does shigella's exotoxin do?
|
Shiga Toxin cleaves host cell rRNA (inactivates 60S ribosome). Also enhances cytokine release--->HUS
|
|
|
What does S. pyogenes' other exotoxin do?
|
Streptolysin O is a hemolysin.
It is also an Ag for ASO Ab which is used as a Dx tool for rheumatic fever |
|
|
Who are the cAMP inducing toxins?
|
Cholera toxin permanently activates Gs
Pertussis toxin permanently disables Gi E.coli's heat labile toxin stimulates adenylate cyclase Antrax toxin is itself an adenylate cyclase They all Inc cAMP |
|
|
so where do we find endotoxins?
|
Lipopolysac in cell walls of gram-negatives
|
|
|
Three main effectors stimulated by endotoxins?
|
Activate Macs
Activate C' (alternative path) Activate Hageman Factor |
|
|
What happens when you activate Macs?
|
IL-1-->fever
TNF--->fever, hemorrhagic tissue necrosis Nitric Oxide--->Hypotension (shock) |
|
|
What happens when you activate the alt. C' path?
|
C3a--->hypotension, edema
C5a---->Neutrophil chemotaxis |
|
|
What happens when you activate the Hageman factor?
|
Coagulation cascade---->DIC
|
|
|
Look at bacterial growth curve
|
lag
log stationary death |
|
|
Keys to Bacterial Genetics?
|
Transformation
Conjugation Transduction Transposition |
|
|
what is Transformation?
|
when DNA is taken up directly from environment
|
|
|
Two types of Conjugation?
|
F+ x F-
Hfr X F- |
|
|
Difference between F+ and F-?
|
F+ plasmid contains the genes needed for conjugation
F- doesn't |
|
|
So what's an Hfr?
|
its a cell that has incorporated the F+ plasmid into its DNA
|
|
|
So what is F+ x F-?
|
when an F+ plasmid is replicated and transferred through a pilus to an F- cell
|
|
|
What is Hfr x F-?
|
Transfer of plasmid AND chromosomal genes
|
|
|
Types of Transduction?
|
Generalized
Specialized |
|
|
What goes on w/ generalized transduction?
|
A lytic phage infects bacterium---> cleavage of bacterial DNA and synthesis of viral proteins. When new viral capsid are made, they may contain bacterial chromosomal DNA...
|
|
|
What goes on w/ specialized transduction?
|
Lysogenic phage infects bacterium-->viral DNA incoporated into bacterial chromosom. When phage DNA is excised for packaging into new capsid, some bacterial DNA may go along with it
|
|
|
What the heck is Transposition?
|
Segment of DNA that can 'jump' (excision and reincorporation) from one location to another from a plasmid to a chromosome or vice versa
|
|
|
What 5 bacterial toxins can be encoded in a lysogenic phage?
|
ABCDE
shigA-like toxin Botulinum Cholera Diphtheria Erythrogenic toxin of strep pyogenes |
|
|
Gram Positive Algorithm?
|
So its Gram Positive, is it Cocci or Bacilli?
Bacilli = options Cocci, is it Catalase + or - Cat +, is it Coagulase + or _ Cat -, check the hemolysis (alpha, beta, or gamma) |
|
|
Ok, so you've got a Gram Positive Rod...it could be?
|
Clostridium (anaerobe)
Corynebacterium Listeria Bacillus |
|
|
So you've got Gram Positive Cocci that are Catalase +, what it is?
|
Staphylococcus
(clusters) |
|
|
So you've got Gram Positive Catalase - Cocci...what it is?
|
Streptococcus
(chains) |
|
|
So you've got Gram Positive Catalase +, Coagulase +, Cocci...what it is?
|
Staph aureus
|
|
|
So you've got Gram Positive, Catalase +, Coagulase - Cocci...what it is?
|
Staph epidermidis
or Staph saprophyticus |
|
|
how do you tell staph epidermidis and staph saprophyticus apart?
|
S. epidermidis is Novobiocin sensitive
S. saprophyticus is novobiocin resistant |
|
|
So you've got gram positive, catalase -, cocci, which = streptococcus...what's the next test to run?
|
Hemolysis
|
|
|
Possible hemolysis results?
|
partial hemolysis (green) = alpha
Complete hemolysis (clear) = beta No hemolysis = gamma |
|
|
So, its gram pos, cat -, alpha hemolytic cocci...what next?
|
Test for a capsule (quellung)
or Optochin test or discover its bile solubility |
|
|
Who could be gram pos, cat -, and alpha hemolytic? result of specifying tests?
|
S. pneumoniae
capsule present Optochin sensitive bile soluble Viridans streptococci (e.g. S. mutans) no capsule optochin resistant not bile soluble |
|
|
Ok, so Gram Positive, catalase negative, beta-hemolytic =?
|
Group A strep (S. pyogenes)
or Group B (S. agalactiae) |
|
|
How do you tell the difference between GAS and GBS?
|
Bacitracin
Group A (pyogenes) is Bacitracin sensitive Group B (agalactiae) is Bacitracin resistant |
|
|
Ok...so gram positive, catalase negative, gamma hemolytic =?
|
Enterococcus
Peptostreptococcus |
|
|
Besides Strep pyogenes (A) and Strep agalactiae (B), who else is a beta-hemolytic bacteria?
|
Staph aureus
Listeria monocytogenes |
|
|
Kickers for Listeria monocytogenes?
|
TUMBLING MOTILITY
causes meningitis in newborns can get it from unpasteurized milk |
|
|
Role of Catalase?
|
Degrades H2O2, an antimicrobial product of PMNs.
staph make catalase (makes them worse). strep doesn't |
|
|
What is unique about the staph aureus food-poisoning-inducing toxin?
|
it is preformed. that's why it hits hard and FAST
|
|
|
Three spectrums of disease caused by Staph aureus?
|
Inflammatory Disease
Toxin-mediated disease MRSA infection |
|
|
Inflammatory disease staph aureus causes?
|
skin infections
organ abscesses pneumonia |
|
|
Toxin-mediated diseases caused by staph aureus?
|
Toxic shock syndrome
scalded skin syndrome rapid-onset food poisoning |
|
|
what is MRSA resistant to?
|
methicillin
but more generally to Beta-lactams thanks to altered penicillin-binding protein |
|
|
When do we see Staph epidermidis?
|
Infections of prosthetic devices and catheters
Normal skin flora Contaminates blood cultures |
|
|
Strep pneumoniae is the most common cause of?
|
Meningitis
Otitis Media (in kids) Pneumonia Sinusitis MOPS (most optochin sensitive) |
|
|
What happens to sickle cell pts or splenectomy pts w/ S.pneumoniae?
|
rusty sputum
sepsis |
|
|
Keys to the virulence of S. pneumoniae
|
Encapsulated
IgA protease |
|
|
Two types of Viridans streptococci?
|
S. mutans
S. sanguis |
|
|
Where do you normally see Viridans strep?
|
S. mutans: Normal flora of oropharynx ---> caries
S. sanguis: subacute bacterial endocarditis |
