Chap8- Bacterial Infections Flashcards Preview

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Flashcards in Chap8- Bacterial Infections Deck (91):
1

What are the pyogenic cocci and what they typically cause

Staph aureus and Staph epidermidis: Abscess, cellulitis, penumonia, sepsis
Strep pyogenes: pharyngitis, scarlet fever
Strep pneumoniae: lobar pneumonia, meningitis
Neis gonorrhea: gonorrhea
Neis meningitis: meningitis

2

What are the common gram - infections and what do they cause

E coli, Klebsiella penumoniae
Enterobacter aerogenes
Proteus spp
Serratia marcescens
Pseudomonas spp
All above cause UTI, wound infection, abscess, pneumonia, sepsis, shock, endocarditis
Bacteroides spp: anaerobic infection
Legionella spp: legionnaires disease

3

What are the contagious childhood bacterial disease pathogens and what do they cause

Haemophilus influenze: meningitis, upper and lower respiratory tract infections
Bordetella pertussis: Whooping cough
Corynebacterium diphtheriae: diphtheria

4

What are the enteric infections and what do they cause

Enteropathogenic E coli and shigella spp

Vibrio Choleae, Campylobacter jejuni, C coli

Yersinia enteroclitica, salmonella spp

ALL above cause invasive or noninvasive gastroentercolitis
Salmonella typhi causes typhoid fever

5

What are the clostridial infections and what do they cause

clostridium tetani: tetanus
clostridium botulinum: botulism
Clostridium perfringens and C septicum: gas gangrene, necrotizing cellulitis
C difficile: pseudomembranous colitis

6

What are the zoonotic bacterial infections and what they cause

bacillus anthracis: anthrax
yersinia pestis: bubonic plague
Francisella tularensis: tularemia
Brucella melitensis, B suis and B abortus: brucellosis
Borelia recurrentis: relapsing fever
Borrelia burgdorferi: lymes

7

What is the human treponemal infection and what does it cause

treponema pallidum: syphilis

8

What are the mycobacterial infections and what they cause

M tb, M bovis: TB
M leprae: leprosy
M kansasii, avium, intracellulare: atypical mycobacterial infections

9

What does nocardia asteroides cause

nocardiosis

10

What are the gram + cocci

staphylococcus and streptococcus and enterococcus

11

What are the gram+ rods

diphtheria, listeriosis, anthrax and nocardiosis, and clostridia

12

What can staphylococcus infections cause

skin lesions, absecesses, sepsis, osteomyelitis, pneumonia, endocarditis, food poisoning and TSS

13

What staph infection is common in UTI of young women

S saprophyticus

14

How does S aureus attach to endothelial cells

has surface R for fibrinogen, fibronectin and vitronectin

15

What enzyme does S aureus have to cause skin abscesses

lipases

16

How does S aureus escape Ab-mediated immunity

have protein A that binds to Fc R of Ig

17

describe the toxins in S aureus

alpha toxin- pore forming protein that will depolarize cell
beta toxin- sphingomyelinase
delta toxin- detergent like peptide
y toxin and leukocidin lyse RBC and phagocytic cells

18

What are the A and B toxins from S aureus

serine proteases that cleave protein desmoglein 1 causing keratinocyte detachment and loss of barrier function

19

TSS is characterized how clinically

hypotension (shock) renal failure, coagulopathy, liver disease, respiratory distress, generalized erythematous rash, soft tissue necrosis

20

What other than S aureus can cause TSS

Strep pyogenes

21

What is a furuncle or boil

focal suppurative inflammation of skin and subcut
hariy areas like face, axilla, groin and legs

22

what is a carbuncle

deeper suppurative infection that spreads laterally beneath deep sub cut fascia and surfaces in multiple adjacent skin sinuses
upper back and posterior neck

23

What is hidradenitis

chronic suppurative infection of apocrine glands most often in axilla

24

What are paronychia and felons

S aureus infections of nail bed or palmar side of fingertips that is painful

25

What does s aureus look like in lungs

polymorphonuclear infiltrate with alot of tissue destruction

26

What is Ritter disease

Staph scalded skin syndrome which occurs alot in children
sunburn like rash over entire body and evolves to bullae

27

how do you determine scalded skin syndrome vs toxic epidermal necrolysis or lyells disease

syndrome occurs at the level of granulosa layer rather than the epidermal-dermal junction

28

What is S aureus becoming resistant to

Methicillin, penicillins and cephalosporins
beta lactam cell wall synthesis inhibitors

29

What does strepcocci usually cause

suppurative infections of skin, oropharynx, lungs and heart valves

30

What post infectious syndromes are tied to strepcocci

rheumatic fever
IC glomerulonephritis
erythema nodosum

31

group A strepcocci cause what

pharyngitis, scarlet fever, erysipelas, impetigo, rheumatic fever, TSS and glomerulonephritis

32

Group B strepcoccie cause what

colonize female genital tract and cause sepsis
neonates- meningitis
intrauterine- chorioamnionitis

33

What is the main cause of dental a=caries

Strepcocci mutans

34

Enterococci are related to what infections

endocarditis and UTIs
and vancomycin Resistant!

35

Which Strepcocci have capsules to resist phagocytosis

S pyogenes, S agalactiae and S pneumoniae

36

What are the virulent factors of S pyogenes

M protein that prevents phagocytosis
complement C5a peptidase
exotoxin that causes fever and rash in scarlet fever
can cause rapid necrotizing fasciculitis

37

What exotoxin does strep pneumoniae have

pneumolysin that lyses cells and activates classical C' pathway reducing C' opsonization

38

What is characterization of strepcocci infections

diffuse interstital neutrophilic infiltrates with minimal destruction--! key to differentiating staph

39

what is erysipelas

rapidly spreading erythematous cutaneous swelling on face or body or extremity
butterfly distribution on face
maybe microabscesses

40

What is the major antecedent of poststrep gomerulonephritis

strept pharyngitis
edema, epiglottic swelling, punctate abscess of tonsillar crypts

41

When is scarlet fever most common

btwn age 3 and 15
punctate erythematous rash over trunk and inner arms/legs
leads to hyperkeratosis

42

What virulent factor does C diphtheriae have

phage encoded A-B toxin that blocks host cell protein synthesis
A fragment catalyzes covalent transfer of ADP-ribose to elongation factor-2 inhibiting it so mRNa cannot be tralated

43

how does the formalin fixed C diphtheria vaccine work

protects against the toxin that is released, does not prevent colonization

44

Describe how C diphteriae is transmitted

inhaled attaches to mucosa and then release of exotoxin causes epithelial necrosis with fibrinosuppurative exudate

45

why is there HSM seen in C diphtheria infections

soluble exotoxin in the blood

46

What population is more susceptible to L monocytogenes and what is the main risk for each

pregnant women- amnionitis resulting in stillbirth, abortion or neonatal sepsis
neonate: meningitis or granulomatous infantiseptica
immunocompromised, elderly

47

Describe the virulence factors of L monocytogenes

internalins on surface that bind E cadherin and internalize the bacteria
poreforming protein listerolysin O and 2 phospholipases that degrade phagolysosomes
induces actin polymerization in the cell to propel bacteria to other cells

48

What cells are primary defense on L monocytogenes infections and why

NK cells and T cells because respond to IFN-y
evade C3 activated macrophage killing

49

what is the main lymphocyte in an acute L monocytogenes

neutrophils

50

What is Diganostic for L monocytogenes

gram + bacilli in CSF

51

What is the most virulent factor of bacillus anthracis

spores that are formed

52

What are the 3 major anthrax syndromes

cutaneous anthrax
inhalational anthrax
gastrointestinal anthrax

53

describe cutaneous anthrax rxn

painless, pruritic papule that develops into a vesicle with edema around it and lymphadenopathy
after vesicle ruptures there is black eschar with dries and heals

54

describe inhalational anthrax

hemorrhagic mediastinitis
1-6 days fever, cough, chest or abdominal pain
fever, hypoxia and sweating
leads to shock in death in 1-2 days

55

describe GI anthrax

nausea, abdominal pain, vomiting, severe bloody diarrhea with mortality over 50%

56

What are the other virulent factors of bacillus anthracis once in the cell

have antiphagocytic capsule with AB toxins
B fragment is protective Ag
A fragment has 2 subunits: edema factor or lethal factor
3 A units and B heptamer endocytosed and then a channel is formen where EF and LF move into cytoplasm activating cAMP causing water efflux and intersitial edema
LP kills MAPKKinases that regulate MAPKs

57

What is suggestive of B anthracis Dx

large box car shaped gram+ bacteria in chains

58

Where does B anthracis predominately inhabit in lungs

alveolar capillaries and venules and sometimes alveolar space

59

What do nocardia bacteria look like

gram + in distinctive branched chains
stain with modified Acid Fast

60

Most patients with N. asteroides have defects in what

T cell mediated immunity like steroid use, HIV or diabetes

61

What is respiratory N asteroides mistaken for alot

TB

62

What does a N asteroides infection look like morphologically

suppurative with central liquefactive necrosis and surrounding granulation and fibrosis
NO granulomas

63

When does N meningitidis become an invasive disease

when a person is exposed to a serotype (13) that they are not immune to
usually close quarter living like dormitories

64

Describe what has to occur in order for an infected patient with N meningitidis to actually get meningitis

bacteria invade resp epithelial cells and enter blood where they inhibit opsonization and destruction by C'

65

What are the two most common STDs

1 is C trachomatis
2 is N gonorrhea

66

What does gonorrhea look like in males? females?

m: urethritis
f: asymptomatic

67

What can untreated infeciton of gonorrhea in a woman lead to

ectopic pregnancy, infertility

68

Infection of gonorrhea is Dx how

PCR and culture

69

What type of people are prone to disseminated gonorrhea? and what does this look like

C' defects
septic arthritis
rash of hemorrhagic papules and pustules

70

What do we give newborns to prevent blindness from gonorrhea directly after birth

silver nitrate or antibiotics

71

How does neisseria escape immune defenses

able to change its expressed Ag on the Pili which bind to CD46

72

What factor do the neisseria genus have to increase binding and promotion of entry into host cells

OPA proteins
gonorrhea has 4
meningitidis has 12

73

What type of bacteria causes whooping cough and what does it look like

bordetella pertussis
gram negative coccobacillus

74

Where does bordetella pertussis colonize

brush border bronchial epithelium and invades macrophages

75

Describe pertussis toxin

5 distinct proteins
catalytic peptide S1 which ADP-ribosylates and inactivates guanine nucleotide binding proteins so G proteins can't transduce signals
also the toxin paralyzes the cilia

76

What does P aeruginosa cause

pulmonary failure
keratitis
endocarditis
osteomyelitis
external otitis

77

What are the exotoxins in pseudomonas aeruginosa

alginate biofilm
exotoxin A that inhibits protein syntehsis by ADP ribsylating EF-2
releases exoenzyme S which ADP ribsylates RAS and other G proteins
Secretes phospholipase C to lyse RBC and pulm surfactant

78

What toxic component is released by p aeruginosa that is super toxic to endothelial cells

iron-containing compunds

79

What does pseudomonas pneumonia look like

necrotizing through terminal airways with pale necrotic centers and red hemorrhagic periphery

80

What is the appearance of p aeruginosa in burns

ecthyma gangrenosum
necrotic and hemorrhagic oval skin lesions

81

What type of bacteria is yersinia pestis

gram - facultative intracell bacterium that is trasnmitted from rodents or flea bites
causing the plague

82

What is the virulent factor or Y pestis

Yop virulon which kills host phagocytes
type III secretion that syringe like projects from bacterial surface into host to inject toxins

83

What Yop from Y pestis inhibits LPS pathways

YopJ

84

What is the morphology of Y pestis

lymph node enlargement, pneumonia, sepsis, neutrophilia
massive proliferation of organisms with protein and polysaccharide rich effusions with dew inflammatory cells but lots of swelling
necrosis of tissues and blood vessels and neutrophilic infiltrates accumulate next to necrotic areas

85

Describe bubonic plague

infected fleabite that starts as small pustule and grows rapidly becomes pulpy and plum colored then ruptures

86

What is the pneumonic plague

severe confluent hemorrhagic and necrotizing bronchopneumonia with fibrinous pleuritis

87

What is septicemic plague

lymph nodes are rich in mononuclear phagocytes that develop areas of necrosis

88

What causes chancroid

hemophilus decreyi

89

What does a chancroid look like

irregular ulcer may be a couple lesions
shaggy yellow gray exudate and there is regional lymph node enlargement

90

Describe appearance of granuloma inguinale

begins as raised papular lesion on moist stratified squamous epithelium of genitalia
usually ulcerates and makes alot of granulation tissue

91

What stains are used for granuloma inguinale

donovan bodies in macrophages and silver stains