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Flashcards in Innate Immunology/Bacteria Deck (61):
1

Superficial skin infections of S. pyogenes

Impetigo, erysipelas

2

Deep skin infections of S. pyogenes

Cellulitis, necrotizing fasciitis, myositis

3

Main infection associated with S. pyogenes

Pharyngitis

4

Toxin-mediated disease of S. pyogenes

Scarlet fever and streptococcal toxic shock syndrome

5

Post-streptococcal disease (non-suppurative)

Rheumatic fever and glomerulonephritis

6

Pharyngitis

Abrupt onset of sore throat, fever, and headache; posterior pharynx erythematous with exudate; tender cervical adenopathy

7

Scarlet fever

Diffuse erythematous eruption; sandpaper rash beginning on chest and extending towards extremities and strawberry tongue; mediated by strptococcal pyrogenic exotoxin (SPE)

8

Acute rheumatic fever/heart disease

Erythema marginatum (pinkish erythematous rash involving trunk and sometimes limbs, but not face)

9

Glomerulonephritis

Acute inflammation of renal glomeruli with edema, hypertension, hematuria, and proteinuria; deposition of immune complexes triggers complement activation and inflammation

10

Impetigo

Primary - direct bacterial invasion of previously normal skin
Secondary - infection at sites of minor skin trauma; nonbullous (most common, papules surrounded by erythema>>pustules that enlarge and break down to form golden crusts

11

Erysipelas

children and young adults; Superficial skin infection with lymph node enlargement and systemic symptoms; skin raised with clear demarcation

12

Cellulitis

Rapidly spreading infection of dermis and subcutaneous fat with poorly defined, flat borders; erythema, pain, warmth, swelling; risk factors - breaks in skin, chronic skin disease

13

Necrotizing fasciitis

bacteria infect fascia; high mortality; progresses rapidly over several days (skin changes color, breakdown with bullae, cutaneous gangrene may be seen); risk factors - penetrating wounds, surgical wounds, immunosuppression, diabetes, obesity

14

Streptococcal TSS

Initial manifestation - inflammation, pain, fever, chills, nausea, vomiting, diarrhea
Subsequent manifestations - shock and organ failure, bacteremic, necrotizing fasciitis; risk groups - HIV, cancer, diabetes, heart/pulm disease, VZV infection, and drug/alcohol abusers; SpeA and C facilitate disease

15

Pseudomonas aeruginosa clinical diseases

SSTI: hot tub folliculitis, ecthyma gangrenosum (neutropenic), burn wounds
Pulmonary, UTI, ear, eye, bacteremia and endocarditis

16

General CoNS infections

Bacteremia (nosocomial) in neonates mostly, infections in patients with medical devices

17

S. epidermidis clinical diseases

Implanted device infections, Subacute endocarditis

18

S. saprophyticus clinical diseases

UTI

19

S. haemolyticus clinical disease

implanted device infections

20

S. lugdunesis clinical diseases

Endocarditis similar to S. aureus

21

S. aureus clinical diseases

Abscesses, cellulitis, folliculitis, furuncles and carbuncles, impetigo, scalded skin syndrome (Ritter's disease), TSS

22

Abscess formation

Inflammatory response to S. aureus, S aureus attacks PMNs, continued recruitment of immune cells to site, buildup of necrotic PMNs and cell debris (liquefactive and coagulative necrosis); formation of fibrous capsule

23

Folliculitis

Cutaneous abscesses in and around hair follicles (papules - discreet elevation or pustules - accumulation of pus in a blister can form)

24

Furuncles

Boils (large, painful, raised nodules); purulent material extends through dermis into subcutaneous tissue and a small abscess forms; pus drains spontaneously or after incision

25

Carbuncles

Clusters of furuncles; deeper subcutaneous tissue involved; treatment: incision and drainage, trimethoprim/sulfamethoxaozole or clindamycin or doxycycline

26

Bullous impetigo

Vesicles enlarge to form flaccid bullae with clear yellow fluid that later becomes darker and more turbid; caused by exfoliative toxins

27

Scalded skin syndrome

Skin tenderness, large bullae, and desquamation or epithelium; blisters contain fluid with no bacteria as symptoms are due to exfoliative toxins A and B

28

TSS

erythematous rash; purpura fulminans (large purpuric skin lesion and disseminated intravascular coagulation); treatment - empiric with IV clindamycin and vanco (MSSA - IV clindamycin plus oxacillin; MRSA - IV clindamycin plus vanco)

29

Extracellular TLRs

1,2,4,5,6

30

Endosomal TLRs

3,7,8,9

31

Lipopeptide TLR

1,2,6

32

Peptidoglycan TLR

2

33

LPS TLR

4

34

Flagella TLR

5

35

Glycoprotein TLR

2,4

36

HSPs and HMGB1 (DAMPs) TLR

2,4

37

Unmethylated CpG DNA TLR

9

38

RNA TLR

3,7,8

39

NLRs

peptidoglycan, flagellin, unmehtylated CpG DNA, RNA

40

RLRs

RNA

41

IL-1

Secreted by: macrophages, PMNs, and endo cells; endo cells increase E-selectin, induce APP in hepatocytes, induce fever

42

TNF-alpha

Same as IL-1 but secreted mostly by macrophages, integrin increase affinity on PMNs

43

IL-6

Secreted by: macrophages, PMNs, endo cells, fibroblasts; induce APP production, stimulate PMN production in marrow; induce fever; naive T cell differentiation

44

IL-8

Secreted by: monocytes, macrophages, PMNs; chemokine that recruits PMNs via increased integrin affinity

45

IL-12

Secreted by: DCs and macrophages; stimulates IFN-gamma production in NK and T cells; enhance NK and CD8 T cells cytotoxic function; differentiation of naive T cells

46

Histamine

Secreted by mast cells; increase vascular permeability and vasodilation

47

PGD2

Secreted by mast cells; vasodilation and increase vascular permeability; PMN recruitment

48

Leukocyte recruitment

1.) Selectin-mediated rolling of leukocytes on endothelium
2.) Integrin conformational change to high affinity state
3.) Integrin-mediated arrest of leukocytes on endothelium
4.) Transmigration of leukocytes through endothelium (diapedesis)

49

Pathogen phagocytosis recognition

1.) PRRs
2.) FcgammaRI (recognizes Fc portion of antibodies)
3.) CR1 complement pathways

50

Phagocytosis steps

1.) Microbe detected, phagocyte membrane surrounds via receptor-mediated endocytosis
2.) Phagosome forms
3.) Phagosome fuses with lysosome to form phagolysosome
4.) microbe digested by microbicidal molecules (oxygen-dependent via phagocyte oxidase complex and iNOS or oxygen-independent via proteolytic enzymes, elastase, cathepsin G, lysozyme, phosphatases, or defensins)

51

Acute phase proteins

CRP (phosphoylcholine), MBL (lectin complement), fibrinogen (clot formation), SAP (phosphatidylehtanolamine), and complement pathway proteins

52

Functions of complements

Opsonize microbes, stimulate inflammation, lysis of microorganisms

53

Alternative

C3>>C3b>>microbe (or degrade by H2O)>>factor B recruited and cleaved by factor D>>forms C3bBb (C3 convertase)>>stabilized by properdin>>recruits C3 for more C3b>>induces formation of C3bBbC3b (C5 convertase)>>C5 produces C5a and b>>C5b recruits C6>>C7>>C8>>C9 forms pore>>microbe dies by osmotic lysis

54

Classical

C1q(r2s2) associates with IgG or IgM>>r2s2 cleave C4 and C2 and C4b and C2a bind to membrane>>forms C4b2a (C3 convertase)>>recruits C3 and cleaves into a and b>>C3b binds and forms C4b2a3b (C5 convertase)>>cleaves C5>>C5b recruits C6>>C7>>C8>>C9 forms pore and microbe dies by osmotic lysis

55

Lectin

MBL recognize polysaccharide>>MBL associates with MASPs>>cleave C4 and C2>>form C4b2a (C3 convertase)>>C3 recruited and cleaved>>C3b binds and forms C4b2a3b (C5 convertase)>>recruits and cleaves C5>>C5b recruits C6>>C7>>C8>>C9 forms pore and microbe dies by osmotic lysis

56

DAF

associates with C3b or C4b to competitively inhibit Bb or 2a from binding to form C3 convertase

57

MCP/CR1

Associate with C3b, enables factor I (or H) to proteolytically cleave C3b to iC3b

58

CD59

Associates with C7/8 to prevent MAC formation

59

C1 INH

Sequesters C1r2s2 complex to prevent activation of classical complement pathway (also targets MASP so lectin also affected)

60

Integrins

PMNs, monocytes, naive B and T cells express LFA-1 binds to ICAM-1 on endo eclls, lymphocytes, DCs and macrophages; monocytes express VLA-4 binds VCAM-1 on endo cells; monocytes express Mac-1 which binds ICAM-1

61

Selectins

Endo cells express P and E-selectin bind to sialyl Lewis X ligand on monocytes, PMNs, and effector T; monocytes, PMNs, and naive B/T express L-selectin bind to sialyl Lewis X ligand on endo cells