Other Pyogenics/Diseases of Childhood/Gram Negs Flashcards

1
Q

Causes of meningitis in neonates

A

E. coli, Strep group B

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2
Q

Causes of meningitis in adolescents and young adults

A

N. meningitis

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3
Q

Causes of meningitis in children aged 1-5

A

H. influenzae type B (before vaccine)

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4
Q

Most common cause of meningitis in all age groups

A

Streptococcus pneumoniae

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5
Q

Most common causes of sinusitits/AOM

A

Streptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
Staphylococcus aureus

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6
Q

Endothelial cell and macrophage activation by what leads to vascular leakage?

A

LPS

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7
Q

Encapsulated bacteria evade what?

A

phagocytosis

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8
Q

What organ eventually cleans encapsulated bacteria?

A

the spleen

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9
Q

Asplenia increases risk of infection by

A

encapsulated organisms

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10
Q

Where do encapsulated bacteria find a safe harbor

A

in CSF (no complement)

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11
Q

Morphology of pneumococcus

A

gram positive, diplococcus

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12
Q

Morphology of N. meningitidis

A

gram negative, diplococcus

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13
Q

Morphology of N. gonorrhea

A

gram negative, diplococcus

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14
Q

Morphology of H. influenzae type b

A

gram negative, pleomorphic

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15
Q

Pneumococcus virulence factors

A

polysaccharide capsule

pneumococcal protein C

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16
Q

N. meningitidis virulence factors

A

polysaccharide capsule

lipopolysaccharide

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17
Q

N. gonorrhea virulence factors

A

polysaccharide capsule

lipo-oligosaccharide

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18
Q

H. influenzae type b virulence factors

A

polysaccharide capsule

lipopolysaccharide

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19
Q

Disseminated intravascular coagulation (DIC)

A

systemic activation of coagulation by intravascular bacteria

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20
Q

DIC results in

A

systemic microthrombi followed by hemorrhage after coagulation factors are used up

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21
Q

LPS stimulates

A

toll-like receptors to induce systemic cytokine secretion and endothelial cell activation

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22
Q

Pathogenesis of Corynebacterium diphtheria

A

local epithelial necrosis (pseudomembrane formation); systemically released exotoxin A

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23
Q

Pathogenesis of Bordetella pertussis

A

Cell-bound pertussis toxin with local epithelial inflammation

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24
Q

diseases caused by Streptococcus pneumoniae

A

sinusitis, otitis media, pneumonia in elderly (CA); meningitis

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25
Q

Strep pneumo is the most common cause of which diseases:

A

sinusitis
otitis media
community-acquired, lobar pneumonia
meningitis (in adults and children 1-10)

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26
Q

Strep pneumo infections are associated with:

A

impaired immunity, malnutrition, alcoholism, age

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27
Q

Most important strep pneumo virulence factor

A

pneumococcal capsular protein PspC

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28
Q

other strep pneumo virulence factors

A

pneumolysin, pspA (inhibits alternate complement pathway)

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29
Q

pathology of strep pneumo

A

purulent lesions with creamy white pus; in pneumonia, alveoli filled with fluid and neutrophils

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30
Q

General features of Neisseria

A

gram-negative encapsulated organisms
very susceptible to adverse environmental conditions
complex nutritional requirements including IRON

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31
Q

Location of N. meningitidis in the body

A

enters nasopharynx and colonizes mucosa; inability to confine the bacteria to the mucosal surface leads to clinical disease states

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32
Q

N. meningitidis invasion leads to

A

purulent meningitis or bacteremia; dissemination results in metastatic lesions to skin, meninges, joints, eyes, lungs

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33
Q

incubation period of N. meningitidis

A

less than 1 week

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34
Q

major virulence factor of N. meningitidis

A

polysaccharide capsule that acts as gram negative endotoxin

35
Q

LPS leads to

A

DIC, puerperal rash, microvascular obstruction

36
Q

microhemorrhages in capillaries results in

A

petechial rash, particularly on extremities and ear lobes

37
Q

eventual obstruction of small blood vessels leads to

A

ischemic necrosis of limbs

38
Q

Waterhouse-Friderichsen syndrome

A

hemorrhage into adrenal medulla

39
Q

Where does N. meningitidis occur most often

A

in cluster epidemics such as army recruits, college students

40
Q

Pathologic lesions of N. meningitidis

A

include vascular damage secondary to action of LPS on endothelial cells, and purulent lesions of the meninges

41
Q

N. gonorrhea attaches to

A

columnar and transitional epithelia (pili) - mucosal membranes of the genital tracts, rectum and nasopharynx

42
Q

Neisseria gonorrhea lacks

A

true polysaccharide capsule and doesn’t cause many of the vascular/DIC problems that meningococci cause
LOS instead of LPS

43
Q

Neisseria gonorrhea has

A

IgA protease

44
Q

Neisseria gonorrhea causes

A

gonorrhea, cystitis; can also cause suppurative arthritis (knees, ankles)

45
Q

Pathology of Neisseria gonorrhea

A

suppurative inflammation of mucosal surfaces and subepithelial tissues; grossly purulent lesions and discharge

46
Q

Important points about Haemophilus influenzae

A

upper respiratory, sinusitis/otitis, meningitis (pneumonia)

severe disease, including meningitis most commonly seen in young children

47
Q

Non-invasive H. influenzae

A

upper respitatory, sinusitis/otitis

most forms causing common upper respiratory symptoms are unencapsulated

48
Q

Which capsule type for H. influenzae is the most common causing invasive disease?

A

type b

49
Q

characteristics of (H. influenzae) type b capsule

A

endotoxin characteristics, causing DIC

more resistant to complement cytotoxicity

50
Q

H. influenzae infects through

A

respiratory route - inhalation of infected droplets from active cases and carriers

51
Q

H. influenzae noninvasive local disease due to

A

local overgrowth of colonizing non-encapsulated forms secondary to other pathologic conditions (viral obstruction)

52
Q

Invasive (type b) H.influenzae disease causes

A

meningitis, pneumonia, epiglottitis

53
Q

Invasive (type b) disease likely secondary to

A

dissemination through blood stream

54
Q

window of susceptibility for invasive disease (type b)

A

3 mos to 3 years

during this time, young children are unable to make a good protective antibody response to the type b capsular antigens

55
Q

why is the H. influenzae vaccine conjugated?

A

infants make poor antibody responses to the capsule polysaccharides; however, by conjugating the polysaccharides with protein, the conjugated vaccine is effective in infants

56
Q

H. parainfluenzae

A

normal flora of the mouth

may result in endocarditis

57
Q

H. ducreyi

A

chancroid

58
Q

M. catarrhalis ithe 3rd most common cause of

A

secondary bacterial infections such as sinusitis and otitis media

59
Q

What does Moraxella catarrhalis have?

A

lipopolysaccharide exotoxin similar to Neisseria; rarely causes septicemia and meningitis

60
Q

Infections of childhood often associated with?

A

unprotected window between loss of maternal IgG and self IgG/IgA production

61
Q

Bordetella pertussis has a strong tropism for

A

brush border; exotoxin leads to local ciliary paralysis with secondary inflammation

62
Q

Whooping Cough vaccine

A

DTP vaccine; immunization leads to production of antibody to the exotoxin

63
Q

Pathology of Corynebacterium diphtheria

A

ulcerative lesions of the respiratory mucosa; leads to coagulative exudate and formation of “pseudomembrane”

64
Q

Corynebacterium diphtheria extoxin leads to

A

fatty myocardial changes, myofiber necrosis, and polyneuritis
causes toxicity by inhibiting protein synthesis

65
Q

General characteristics of gram negative rods

A
  1. endotoxins: lipopolysaccharides
  2. frequent drug resistance
  3. has replaced pyogenic cocci as bulk of hospital-acquired and opportunitistic infections
66
Q

When does E. Coli cause disease

A

when they gain access to tissues (peritoneum, urinary tract, sepsis) or secondary to tissue inflammation in abdomen (appendicitis, obstruction)

67
Q

Types of infection caused by E. Coli

A
  1. urinary tract infections/cystitis
  2. suppurative infections of the abdominal cavity
  3. gram negative hemorrhagic bronchopneumonia in debilitated patients
  4. gram negative sepsis: DIC/shock
68
Q

Suppurative infections of the abdominal cavity can be:

A

secondary to obstruction: appendicitis, cholecystitis, diverticulitis
performation, trauma (including surgery)

69
Q

Klebsiella pneumonia associated with

A

aspiration in a hospital setting

70
Q

Proteus mirabilis

A

UTI/pyelonephritis; pneumonia (debilitated patients)

71
Q

Serratia marcescens

A

pneumonia (debilitated patients)

72
Q

Pseudomonas aeruginosa

A

rod-shaped gram negative; motile, flagellum, aerobic, non-spore forming

73
Q

Pseudomonas aeruginosa contains

A

fluoroscein pigment - pyocyanin and pyoverdin

74
Q

Where is pseudomonas

A

ubiquitous in hospitals - cultured extensively from surfaces in hospitals

75
Q

What immune response protects from an pseudomonas infection?

A

phagocytosis

76
Q

Pseudomonas is a frequent deadly pathogen in patients with

A

cystic fibrosis, severe burns, or neutropenia

77
Q

psuedomonas is characterized by

A

necrotizing inflammation
vasculitis with abundant organisms
BLUE HAZE

78
Q

Pseudomonas virulence factors

A
endotoxin - LPS
extotonix A similar to diphtheria
protective exopolysaccharide (biofilms)
phospholipases
Fe-containing compounds toxic to endothelial cells
leukocidin
79
Q

Pseudomonas lung infections

A

fulminant pneumonias

80
Q

Other forms of pseudomonas infections

A

corneal keratitis in wearers of contact lenses
endocarditis and osteomyelitis in IV drug users
external otitis
severe external otitis in diabetics

81
Q

Anaerobic gram-negative bacterial infections

A

Bacteroides
Fusobacterium
Peptococcus
Peptostreptotoccus (gingival infections)

82
Q

foul-smelling pus and mixed-infections associated with

A

anaerobic gram-negative bacterial infections

83
Q

Legionella

A
  1. small gram-neg. flagellate rod
  2. community outbreaks associated with contaminated aerosolized water supplies
  3. most common inindividuals with pre-disposing lung/heart disease, including organ transplant
  4. fibrinopurulent necrosis leads to scarring of pulmonary tissues
84
Q

Helicobacter pylori

A

spiral/helical gram negative, motile, urease

commonly found in antrum