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Micro
Kaplan2 - Bacteriology; Gram+ Cocci
31
Accounting
Pre-School
03/31/2013

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Cards

Term
What are the functional differences between Staph and Strep along with the differences between their subspecies? What are all the members? (See 239 mainly)
Definition
-Hit the cat with the Staph (Staph are catalase+)
-Staph aureus is the only one with coagulase
-Hemolysis is more complicated
-Know the three antibiotic resistances
Term
What are alpha, beta, and gamma hemolysis?
Definition
-Beta is total, alpha some, gamma none
Term
What defines Staph epidermidis and saprophyticus in terms of distinguishing the two?
Definition
-In both we're concerned about UTI's more than anything
-Epi is more with older women with catheters
-Sapro is more with young women who just started having sex (Think sapphic)

-Additionally, epi is sensitive to *novobiocin, and sapro is resistant

-Epi can also cause endocarditis; mostly in IVDUs, and in patients with prosthetic valves (likes plastic apparently)
Term
How do we test for staph aureus/identify it?
Definition
-A coagulase test is very telling (only gram+ cocci with it)
-It makes **yellow colonies on *blood agar (and also clears the blood because of the beta-hemolysis)
-It also ferments *mannitol and is *salt tolerant (grows on *mannitol-salt agar)
Term
Where do we usually find Staph aureus? How is it transmitted?
Definition
-In the boogies
-Then it gets on the fingies lol

-Can be from hand contact, sneezing, and often in foods (namely; custards, potato salad, and canned meats)
Term
What are the risk factors for S. aureus?
Definition
-*Surgery/wounds (one of most common)
-TSS from leaving tampons in back in the day
-Also, *CGD because all Staph species are *catalase+
Term
What does staph aureus have that makes it virulent?
Definition
1. Major is **TSST
2. Also has enterotoxins (important in food poisoning... from the boogies haha)
3. Exfolatins; cause the scalded skin syndrome in babies

4. Protein A binds to Fc portion
5. Coagulase - causes it to be more localized
Term
What diseases do we see with S. aureus (9)?
Definition
1. Gastroenteritis; 2-6 hours after eating the toxin (not bacteria, bc the enterotoxin is heat stable)

2. *Endocarditis (acute); usually from **IV drug use (most common cause in druggies; otherwise is second to **viridans Strep (subacute))

3. Abscesses, boils, mastitis (breasts), etc.

4. *TSS; fever, sunburn like rash, peeling palms and soles, hypotension, multiorgan failure, and death (from TSST-1)

5. Impetigo; patchy erythematous papules/bullae, can be Staph or Strep (catalase test needed), often school kids

6. Scalded skin syndrome; in infants from exfoliatins

7. Pneumonia; nosocomial from ventilators with high fatality rate, salmon color (less common cause of pne)

8. Surgery infection; **most common cause of

9. Osteomyelitis; bone infection, more in children, **most common cause of (unless they have sickle cell, then it's salmonella)
Term
How do we treat staph aureus infections?
Definition
-We usually treat with **penicillin drugs such as nafcillin, oxacillin, *methacillin, etc. (all end in -cillin and are B-lactamase resistant)

-However, *MRSA is resistant even to these beta-lactams, so for it we prefer **vancomycin (binds D-ala, D-ala), which is even getting some resistance
Term
Shapewise, what is the diff. b/t staph and strep?
Definition
-Staph are in clusters, strep is in chains (usually)
-Think strep = strip = chains
-Plus staph has coagulase, so it stays concentrated, as another memory tool
Term
What can help us distinguish Strep pyogenes from the other Strep members?
Definition
-It is beta hemolytic (so is group B)
-It is bacitracin sensitive (group B is not)

-Also it is PYR positive (Enterococcus faecalis/faecium is the only other member that is)
Term
Where do we find it on the body and what is transmission?
Definition
-Throat (it is strep after all)--->respiratory droplets
-Skin--->contact
Term
What are the virulence factors for S. pyogenes?
Definition
1. Major is **M-protein; antiphagocytic,
-*M12 strains associated with post strep. glomerulonephritis (PSGN)

2. Exotoxins A-C; act as *superantigens and cause the *fever and rash we see in scarlet fever

3. Capsule; anti phags (of hyaluronic acid)

-Also has streptokinase, a DNAse, and hyaluronidase which all serve to break down tissue enabling spread
Term
What are the diseases for Strep pyogenes (4)?
Definition
1. Pharyngitis; duh

2. Scarlet fever; pharyngitis followed by *sandpaper rash, *strawberry tongue, nausea/vomiting

3. Pyoderma/impetigo; with "honey crusted lesions" (same as with staph and have to use catalase to diff) (impetigo is a type of pyoderma; pus producing cutaneous lesion)

4. Necrotizing fascitis and other skin infections
Term
What are the **sequellae to the primary S. pyogenes infections**?
Definition
-Often secondary to simple Strep throat

5. Rhematic fever; antibodies to heart 2 weeks after
-Hypersensitivity type II (antibody attack of cells)

6. Acute glomerulonephritis (M12 serotype); edema, hypertension, smokey urine
-Type III hypersensitivity (complex mediated)
Term
What is the antibody that leads to the rheumatic fever?
Definition
-Antibodies to streptolysin O (ASO)
-We can test this in a titer
Term
How do we treat Strep pyogenes?
Definition
-B-lactams
-Macrolides in case of penicillin allergy
Term
Define (class);
Folliculitis
Boil
Furuncle
Carbuncle
Osteomyelitis
Erysipelas
Cellulitis
Impetigo (pyoderma)
Definition
Caused mostly by Staph aureus;
-Folliculitis; infection of the hair follicle
-Boil; deep coalesced folliculitis
-Furuncle; a boil
-Carbuncle; same but larger
-Osteomyelitis; bone infection

Caused mostly by Strep pyogenes;
-Erysipelas; dermis infection with blockage of lymphatics (commonly on the cheeks)
-Cellulitis; fat/subQ infections

-Impetigo is caused by both; erythematous with pus
Term
What should we know about Strep agalactiae?
Definition
-***#1 cause of neonatal septicemia and meningitis***; from vagina, esp. with harsh labor

For ID;
-Beta hemolytic
-Bacitracin resistant
-CAMP test positive (arrow head on blood agar)
-Major virulence is capsule and hemolysin
Term
What are the characteristics of Streptococcus pneumoniae? Where do we find it and how is it transmitted?
Definition
-alpha-hemolytic
-*Optochin sensitive (to diff from viridans; also viridans has no capsule)
-Lancet shaped **diplococci with **capsule
-Lysed by bile

-Found in the upper resp. (often normally) and transmitted by droplets (but is not considered highly communicable)
Term
What is the virulence of Strep. pneumoniae?
Definition
1. *Capsule; by far the most important

Also;
2. IgA protease; helps in invasion
3. Pneumolysin; pore forming
Term
What are the predisposing factors for Strep. pneumoniae?
Definition
-Influenza
-COPD
-CHF
-Alcoholism
-Asplenia; susceptible to all the capsular antigens
Term
What are the diseases for Strep. pneumoniae?
Definition
1. Typical pneumonia; blood tinged (*rusty) sputum, fever and chills, *lobar consolidated infection (for X-ray)
2. Adult meningitis; CSF will have high WBC, low glucose, and high protein contents
3. Otitis media and sinusitis in children

-***Most common cause of all three***
Term
How do we diagnose and treat Strep. pneumoniae infections? How can we prevent?
Definition
-*Quellung reaction; positive (shows capsule with addition of type specific antibodies)
-Latex particle agglutination is new and better

-Pneumonia; macrolides (like erythromycin)
-Meningitis; a cephalosporin (B lactam for meningitis)
-Otitis media; B lactams

Pediatric vaccine; PCV (pneumococcal capsular vaccine)
-With seven serotypes
Adult; PPV (pneumococcal polysaccharide vaccine)
-23 serotypes
Term
What are Viridans Streptococci? What differentiates them?
Definition
-They are Strep that endogenous to the **mouth that fall outside of the grouping system (Lancefield serotyping)
-The important ones are *S. mutans & sanguis

-They are differentiated from the rest of Strep because they are *alpha hemolytic (S. pneumoniae is too) and *optochin resistant
Term
What are the diseases, symptoms, and predisposing factors for Viridans Streptococci?
Definition
1. **Endocarditis (*subacute); is the number one cause and is often associated with damaged/prosthetic heart valves, and also with dental work or very poor dental hygiene (and often with both together)
-Is often associated with *splinter hemorrhages under the nails, clubbing, spots on hands, feet, retina, fatigue, etc.

2. Dental caries; S. mutans is the one that makes *plaque
Term
What is the pathogenesis of Viridans Streptococci? How do we treat it?
Definition
-It has *dextran which allows it to form its thick biofilm; on teeth and damaged heart valves

-Treat with penicillin G and aminoglycosides
-Must prophalax patients getting dental work who have damaged heart valves
Term
Define (class);
Endarteritis
Phlebitis
Osler nodes
Definition
-Endarteritis; artery infection (S. aureus)
-Phlebitis; vein infection (S. aureus)
-Osler nodes; painful spots on pads of fingers ant toes, disappear within hours; associated with *endocarditis
-Janeway lesions; same, but painless and days
-Roth spots; on retina; endocarditis sign
Term
(Random for class); What are the top three causes of acute otitis media and acute bacterial rhinosinusitis (sinus infections)?
Definition
1st. Strep pneumoniae
2nd. Haemophilus influenzae
3rd. Moraxella catarrhalis
Term
What are the members and identification strategy for the Enterococcus genus?
Definition
Members; E. faecalis & faecium, both in GI, urethra, & vag.
-Also known as group D Strep.

Identification; Cat neg, PYR+, varied hemolysis (usually *gamma), ***hydrolyzes esculin and is bile and salt tolerant*** (turns **bile esculing agar black)
Term
What diseases do the Enterococci cause? How do we treat and what are the problems with treatment? How do they arise?
Definition
1. *Urinary and biliary infections; because bile/salt tolerant

2. **Infective (subacute) endocarditis; damaged heart valves + GI surgery (Viridans Strep are + dental work)

-Very resistant, and some **vancomycin resistant strains are impossible to treat
-VanA strains have a D-ala-D-lac instead of D-ala-D-ala
-Best to prophylax with penicillin prior to GI/urinary work
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