MMG 552 Final Exam

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Corynebacterium diphtheria: Gram +
Aerobic
Pleiomorphic
Non-motile
Catalase +

Diptheria toxin: must have B-tox phage to cause disease

*Localized destruction of epithelium* - Do not invade cells (transmission is aerosol and fomites)- inflammatory response - pseudomembrane formation - systemic toxemia
Clostridium tetani: Gram + rods
Anaerobic
Motile
Spore-forming

Tetanus toxin: non-transmissible plasmid

Injection of spores into deep wound --> spastic paralysis

*Prevents release of inhibitory NTs at NMJ = lockjaw, stiff neck, stiff back .. respiratory failure

Low ID50 and does not invade cells

Tx with antitoxin HTIG
Clostridium botulinum: Gram + rods
Anaerobic
Motile
Spore-forming

Botulinum toxin: encoded on bacteriophage

No person to person transmission

Flaccid paralysis - *prevents ACH release, inhibiting muscle contraction

- double/blurred vision, drooping eyelids, slurred speech, muscle weakness, NO fever
Vibrio cholerae: Gram - curved rod
Faculative anaerobe
Highly motile
Oxidase +

Cholera toxin: encoded on lysogenic CTX macrophage bacteriophage - increases cAMP

Type II secretion - ToxR

Oral-fecal transmission, explosive watery diarrhea (rice water stools)

*Must ingest organism to cause disease**

No inflammation
Staphylococcus aureus: Gram + cocci
Faculative anaerobe
Non-motile
Catalase +
Coagulase +

Protein A (prevents opsonization by Ab)

Toxic shock syndrome (toxin w/o bacteremia!), scalded skin syndrome, food poisoning, systemic infections
Streptococcus pyogenes: Gram + rods
Faculative anaerobe
Non-motile
Bacitracin sensitive
Catalase -

Scarlet fever, toxic shock-like syndrome (SpeA production.. there IS bacteremia), necrotizing fasciitis, rheumatic fever, glomerulonephritis
Streptococcus pneumonia: Gram + pneumococci
Faculative anaerobe
Catalase -
Bacitracin sensitive
Optochin sensitive

Reservoir: URT Transmission: aerosol

Pneumolysin slows ciliar beating, activates C' pathway, inactivates ox burst
**polysaccharide capusle is required for virulence**
Legionella pneumophila: Gram - rod
Obligate aerobe
Motile
Fastidious
Faculative intracellular (multiple in macrophages!, requires Dot and Icm proteins)
Catalase +

Legionnaire's disease (mortality), pontiac fever

PCN not effective
Mycobacterium tuberculosis: Acid fast rods
Obligate aerobe
Faculative intracellular (multiply in unactivated macrophages)

Does NOT produce exo- or endotoxins

Tuberculin hypersensitivity, primary TB, miliary TB PPD-, latency PPD+, Reactivation TB/secondary TB
Treponema pallidum: Gram - like
Spirochetes
*NO LPS*
corkscrew motile

No known toxins!

Primary, secondary, and tertiary syphilis (also congenital)

Neurosyphilis = irreversible

Difficult to culture!
Borrelia burgdorferi: Gram - like
Spirochetes
NO LPS
corkscrew motile
zoonotic

Fe abstinence!

Lyme disease
- initial phase: erythema migrans (bulls eye rash)

OspA - anchors tick; OspC - target salivary gland; OspE - inhibits C' pathway
Chlamydia trachomatis: Gram - like
No Pg
Don't synthesize AA
Aerobic
Obligate inracellular

*Can't gram stain because too small!*

RB - reticulate body: fragile, replicative form.. produce ATP by ox phos
EB - type III secretion! (EBs at the center.. excit of EBs by vacuole lysis or fusion w/ new host)
Neisseria gonorrhoeae: Gram - diplococci
Faculative anaerobes
Faculative intracellular (non-ciliated epithelial cells)
Oxidase +
Catalse +

LOS --> primary toxin causing damage

Disseminated gonococcal infection --> Tbp allows acquisition of Fe, LOS variants protect from C' pathway, gonococcal arthritis

Purulent exudates
Neisseria meningitidis: Gram - diplococci
Faculative anaerobes
Faculative intracellular (non-ciliated epithelial cells)
Oxidase +
Catalase +

*transient normal flora* asymptomatic carriers

Transmission: respiratory aerosis!

Meningitis, meningococcal septicemia, LOS, disseminated intravascular coagulation (DIC) --> severe endotoxic shock.. 100% mortality without treatment
Enterobacteriaceae ..common themes: Gram -
non-fastidious
non-spore forming
faculative anaerobic
Oxidase -
Survive in bile salts

Types: shigella dysenteriae, salmonella typhi, salmonella enteritidis, E. coli

O-Ag --> LPS
K-Ag --> capsule
H-Ag --> flagellin
Shigella dysenteriae: Ferments glucose, NOT lactose
Doesn't produce H2S

Culture on Triple sugar iron agar = yellow butt, red slant

Type III secretion, decreases Na+ reabsorption, increases luminal fluid, cell death

3 phases:
1. uptake by "trigger" and "membrane" mechanisms
2. escapes phagosome
3. spreads to 2nd cell by polymerized actin tails

Low ID50
Salmonella typhi: Ferments glucose, not lactose
Produce H2S

LPS. Survival in vacuoles of macrophages

Salmonellosis

Culture on TSI agar = black

Self-limiting, antibiotics not needed
Salmonella enteritidis: Ferments glucose, not lactose
Produces H2S

LPS.. same as sal. typ

Typhoid fever
Reservoir in gall bladder to reinfect intestine

culture on TSI agar = black

High ID50
Escherichia coli: Gram - rods
faculative anaerobes
Ferments glucose
Ferments lactose

..multiple subtypes listed later
Enterotoxigenic E. coli: Heat-labile toxin = LT1 (cholera.... increases cAMP), LT2 (animal disease)

Heat-stable toxin = STa (increases cGMP which causes H20 hypersecretion), STb (animal disease)

Colonization factors = CF

Do not invade cells, High ID50, colonize small intestine

Virulence factors encoded on plasmid
Enteroinvasive E. coli: Ipas same as Shigella
No actin tail
Plasmid encoded

Like Shigella, but without Shiga toxin --> higher ID50

Colonize *large* intestine.. watery, sometimes dysentary diarrhea
Enteropathogenic E. coli: Bundle forming pilus (BFP)
Type IV pili --> adherence... (then Type III secretion of Tir into host which inserts into host membrane for intimin to bind)
LEE locus encodeds intimin, Tir, and Esp

Don't invade cell! colonize *small* intestines

Fever, nausea, vomiting, diarrhea (especially in infants!)
Enterohemorrhagic E. coli: LEE locus
Shiga-like toxins encoded on bacteriophage

Acid resistant! - low ID50, identify by sorbitol- (which causes it to turn white, instead of red)

Hemorrhagic colitis - caused by shiga toxin.. may progress into hemolytic uremic syndrome

Colonizes *large* intestine
Uropathogenic E. coli: Type I pili and Pap adhesions (tissue tropism)
Hemolysin (HylA) lyses RBCs (by creating pores)
CNF-1 (causes changes in cytoskeleton)

Causes UTIs and pyelonephritis
Septic E. coli: Capsule: K-Ag
Type I pili and S fimbrae (binds cells of choroid plexus/brain ventricles) adhesions
Ibe, and OmpA invasins

Causes sepsis and meningitis

*fatal in new borns*
Sheep Blood agar: alpha: partial clearing, green or brownish ring

beta: wide zone of clearing

gamma: non-hemolytic
Chocolate agar: Selective for organisms like Neisseria or Haemophilus that might not grow on standard media such as TSA..
Thayer-martin agar: Selective for Neisseriaceae
MacConkey agar: Selective for non-fastidious gram-negatives

red colonies ferment lactose (E. coli)

white colonies do not (Salmonella)

EHEC does not ferment sorbitol, other E. coli do
Eosin-methylene blue agar (EMB): Lactose fermenters = blue/black with metallic sheen

Non-fermenters = colorless or light purple
Hektoen agar: Lactose fermenters = yellow or salmon

Non-Fermenters = colorless

H2S production makes colonies black
Mannitol Salt agar: S. aureus is yellow (ferments mannitol)

other Staph are white
Colistin-naladixic acid (CNA): Selects against enterics and other gram-negatives
Triple Sugar Iron agar (TSI): Ferments glucose only = yellow butt, red slant (K/A)

Ferments glucose + lactose/sucrose = yellow butt, yellow slant (A/A)

Non-utilization of all 3 sugars = red butt, red slant (K/K)

H2S (+) = black

Gas production (G) = bubbles

E. coli --> A/AG
Salmonella --> K/A+G
Shigella --> K/A
P. aeruginosa --> K/K
Endotoxin: Neisseria (both)
Shigella
Salmonella
Legionella (not bad)
Chlamydia
Capsule: Neisseria meningiditis
Septic E. coli (SEC)
Salmonella typhi (Vi antigen)
Staph aureus
Strep pyogenes (hyaluronic acid)
Strep pneumoniae
IgA Protease: Strep pneumoniae
Neisseria gonorrhoeae
Neisseria meningiditis
Type III secretion: Shigella dysenteriae
Salmonella typhi
EPEC
Chlamydia trachomatis
Intracellular pathogens: Shigella dysenteriae
Mycobacterium tuberculosis
Chlamydia trachomatis
Legionella pneumophila
Salmonella spp
Invasions/Adhesions: vibrio - type IV pillus
Legionella - DOT & ICM (type IV secr)
Borrelia - Osp A, C, E
Neisseria - PI (porin), PII (Opa), PIII (Rmp), Fe binding proteins
Shigella/EIEC - Ipa proteins, IcsA/B
Salmonella - Inv H
EPEC/EHEC - LEE locus, BFP, intimin, Tir, Esp, Type IV pilus

UPEC - type I pilus, Pap
SEC - type I pilus, S-fimbriae, Ibe/OmpA = invasins

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Created By alstoner