Pathogenicities
Terms
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- Staphylococcus epidermidis
-
ubiquitous on skin/mucous membranes;
1. Bacterial endocarditis involving prosthetic valve (extracell. slime)
2. Surgical prostethesis infection
3. Bacteremia - Staphylococcus saprophyticus
-
-Not normal flora
-UTI in sexually active 18-25 yr old females - Staphylococcus aureus
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normal flora in skin/mucous membranes;
A. Diseases of skin
1. pimples/acne/folliculitis
2. Boils, furuncles
3. carbuncles
4. impetigo
5. cellulitis
6. Scalded Skin Syndrome (ritters dis)
B. Diseases of Digestive tract - food poisoning
C. Post-op/wound infections
D. Pneumonia
E. TSS-toxic shock
F. Osteomyelitis
G. bactermia, endocarditis, meningitis, UTI, stye. - 6 extracellular substances --> mechanisms for S. aureus disease
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1. Exfoliative toxin
2. Leukocydin
C. enterotoxin (exotoxin, heat-stabile)
D. coagulase
E. protein A
f. others - very virulent - S. aureus food poisoning
-
2-6 hr incubation
unrefrigerated hi-protein food ingestion
nausea, vomit, diarrhea
self-limiting in 24 hrs
cause: enterotoxins A and D - #1 cause of osteomyelitis
- Staph aureus
- Cause/symptoms of TSS
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-Staph aureus TSST-1 exotoxin
Inital - hi fever, dizzy, vomit, diarrh.
48 hrs - sunburn rash, hypotensive - Streptococcus viridans
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Normal flora in mouth/vagina
Subacute Bacterial Endocarditis in damaged (not prosthetic) heart valve (from Rheumatic fever) - Enterococcus
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Normal flora in intestine
-Bacteremia
-Endocarditis
-Wound infections
-UTIs - Strep group D non-enterococcus
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Normal flora in wait it's RARE in humans
endocarditis - S. pneumoniae
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normal flora in oral cavity (small #)
Pathogen because of capsule
1. Lobar pneumonia
2. Meningitis
3. Otitis media
4. Bacteremia - Pathology/symptoms of pneumonia
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GPdC S. pneumonia enter lungs; Lobar consolidation from immune response.
High fever, shaking chills, sharp pleural pain, rusty sputum - Strep group A --> S. pyogenes
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normal flora in oral cavity of some
1. Strep throat
2. Scarlet fever
3. Erysipelas, cellulitis
4. Impetigo
5. Wound infections
6. Pyogenic infections
Necrotizing fasciitis, TSS-like
7. Post-strep diseases (Acute glomerulonephritis, rheumatic fever) - 5 Extracellular products causing Strep pyogenes (groupA) diseases:
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Streptokinase - breaks fibrin, spreads
Streptodornase - degrades DNA of host
Hyaluronidase - degrades connect. tissue
Erythrogenic toxin -scarlet fever color
Hemolysins O and S -
symptoms of strep throat
symptoms of scarlet fever -
pharyngitis, pyogenous tonsils, slight fever, cervical lymphadenopathy
strep throat + red rash from erythrogenic toxin - 2 pyogenic Strep A infections:
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necrotizing fasciitis - flesh eating
toxic shock-like syndrome - 2 post-strep diseases
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1. acute glomerulonephritis
2. rheumatic fever
both are hypersensitive reactions from prior infection. seen app. 3 wks after initial infection. -
Who does Strep group B (agalactiae) typically cause infections in?
Normal flora in: -
NEONATES
-Oral cavity in low #s. May colonize vagina but not normal. - #1 cause of neonatal meningitis and sepsis:
- Strep group B agalactiae
- Infections caused by Strep group B:
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Neonatal Meningitis/Sepsis
Neonatal Respiratory Distress Syndrome (RDS)
Neonatal osteomyelitis -
B-hemolytic STreps not A, B, or D:
normal flora in:
may cause: -
Oral cavity
Pharyngitis - What gram positive catalase neg cocci is intrinsically resistant to Vancomycin?
- Leuconostoc
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Neisseria gonorrhoeae causes what infections?
By what four virulence factors? -
Gonorrhea, Gonococcal pharyngitis, neonatal ophthalmia
-pili
-IgA protease (inhibits IgA)
-endotoxin
-Capsule -
symptoms of gonorrhoea:
(male/female/both) -
Males: urethritis, dysuria, purulent dischare.
Females: cervicitis, vaginitis, itching/discharge or asymptomatic.
Both: proctitis - Gonorrhoea complications:
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PID (pelvic inflammatory disease)
Gonoccal arthritis
Septicemia - Neisseria meningitidis causes what disease?
- Meningitis
- Saprophytic neisseria commonly normal flora in:
- Mouth --> IN EVERY MOUTH CAVITY
- What diseases does Moraxella catarrhalis cause?
- Otitis media, sinusitis, pneumonia, meningitis.
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What infection is caused by Corynebacterium diphtheriae?
What causes the pathogenicity?
Symptoms: -
Diphtheria
Lysogenic phage encoding exotoxin invades the bacteria; causes production.
Pharyngeal membrane, edema, fever, Bull's neck, lymphadenopathy. -
Where are the Diphtheroids normal flora, what type of infection could they cause
which one is most common -
skin, mucous membranes, vagina.
SBE, bacteremia. only opportunistic in susceptible people though.
Most commonly would be C. jeikeium. - Which Corynebacterium causes encrusted cystitis?
- C. urealyticum - produces urease and an NH3 around itself protecting itself from phagocytosis. Chronic UTI
- Type of infection caused by Listeria monocytogenes
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Foodborne illness (from cold packaged hot dogs, cheese, milk)
Septicemia/Meningitis in Neonates and susceptible adults. - What does Erysipelothrix rhusiopathiae usually cause
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Erysipeloid (localized cellulitis)
zoonotic disease from hogs to butcher or vet - 2 types of Bacillus cause what three types of disease?
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B. anthracis - anthrax
B. cereus - diahhretic or emetic food poisoning - 3 variations of Anthrax:
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-Cutaneous (forms black eschers)
-Pulmonary
-Enteritis - Difference between emetic and diarrhetic food poisoning:
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emetic is shorter 1-6 hr incubation
comes from fried rice
diarrhetic is longer 6-24 hr incubation
comes from meats/sauces - Infections by Haemophilus influenzae:
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Respitory: Pneumonia, sinusitis, otitis media.
Meningitis in infants under 2 yrs old
Conjunctivitis/Pinkeye -
What infections would Haemophilus non-influenz. cause (hemolyticus, parainfluenzae, parahemolyticus, etc)?
Where normal flora -
In suscp. patients, Bacteremia or SBE
normal in oral cavity -
what does haemophilus ducreyi cause?
symptoms - chancroid; painful ulcers, inguinal lymphadenopathy
- What bacteria causes whooping cough?
- Bordatella pertussis
- what does bordetella bronchiseptica cause
-
respitory tract infections (pneumonia)
wound infections - what is especially frightening about Listeria monocytogenes?
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If acquired during pregnancy, can cross the placenta and cause stillborn birth in a neonate.
or cause fetal infections of septicemia and meningitis.