Other Pyogenics/Diseases of Childhood/Gram Negs Flashcards
1
Q
Causes of meningitis in neonates
A
E. coli, Strep group B
2
Q
Causes of meningitis in adolescents and young adults
A
N. meningitis
3
Q
Causes of meningitis in children aged 1-5
A
H. influenzae type B (before vaccine)
4
Q
Most common cause of meningitis in all age groups
A
Streptococcus pneumoniae
5
Q
Most common causes of sinusitits/AOM
A
Streptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
Staphylococcus aureus
6
Q
Endothelial cell and macrophage activation by what leads to vascular leakage?
A
LPS
7
Q
Encapsulated bacteria evade what?
A
phagocytosis
8
Q
What organ eventually cleans encapsulated bacteria?
A
the spleen
9
Q
Asplenia increases risk of infection by
A
encapsulated organisms
10
Q
Where do encapsulated bacteria find a safe harbor
A
in CSF (no complement)
11
Q
Morphology of pneumococcus
A
gram positive, diplococcus
12
Q
Morphology of N. meningitidis
A
gram negative, diplococcus
13
Q
Morphology of N. gonorrhea
A
gram negative, diplococcus
14
Q
Morphology of H. influenzae type b
A
gram negative, pleomorphic
15
Q
Pneumococcus virulence factors
A
polysaccharide capsule
pneumococcal protein C
16
Q
N. meningitidis virulence factors
A
polysaccharide capsule
lipopolysaccharide
17
Q
N. gonorrhea virulence factors
A
polysaccharide capsule
lipo-oligosaccharide
18
Q
H. influenzae type b virulence factors
A
polysaccharide capsule
lipopolysaccharide
19
Q
Disseminated intravascular coagulation (DIC)
A
systemic activation of coagulation by intravascular bacteria
20
Q
DIC results in
A
systemic microthrombi followed by hemorrhage after coagulation factors are used up
21
Q
LPS stimulates
A
toll-like receptors to induce systemic cytokine secretion and endothelial cell activation
22
Q
Pathogenesis of Corynebacterium diphtheria
A
local epithelial necrosis (pseudomembrane formation); systemically released exotoxin A
23
Q
Pathogenesis of Bordetella pertussis
A
Cell-bound pertussis toxin with local epithelial inflammation
24
Q
diseases caused by Streptococcus pneumoniae
A
sinusitis, otitis media, pneumonia in elderly (CA); meningitis
25
Strep pneumo is the most common cause of which diseases:
sinusitis
otitis media
community-acquired, lobar pneumonia
meningitis (in adults and children 1-10)
26
Strep pneumo infections are associated with:
impaired immunity, malnutrition, alcoholism, age
27
Most important strep pneumo virulence factor
pneumococcal capsular protein PspC
28
other strep pneumo virulence factors
pneumolysin, pspA (inhibits alternate complement pathway)
29
pathology of strep pneumo
purulent lesions with creamy white pus; in pneumonia, alveoli filled with fluid and neutrophils
30
General features of Neisseria
gram-negative encapsulated organisms
very susceptible to adverse environmental conditions
complex nutritional requirements including IRON
31
Location of N. meningitidis in the body
enters nasopharynx and colonizes mucosa; inability to confine the bacteria to the mucosal surface leads to clinical disease states
32
N. meningitidis invasion leads to
purulent meningitis or bacteremia; dissemination results in metastatic lesions to skin, meninges, joints, eyes, lungs
33
incubation period of N. meningitidis
less than 1 week
34
major virulence factor of N. meningitidis
polysaccharide capsule that acts as gram negative endotoxin
35
LPS leads to
DIC, puerperal rash, microvascular obstruction
36
microhemorrhages in capillaries results in
petechial rash, particularly on extremities and ear lobes
37
eventual obstruction of small blood vessels leads to
ischemic necrosis of limbs
38
Waterhouse-Friderichsen syndrome
hemorrhage into adrenal medulla
39
Where does N. meningitidis occur most often
in cluster epidemics such as army recruits, college students
40
Pathologic lesions of N. meningitidis
include vascular damage secondary to action of LPS on endothelial cells, and purulent lesions of the meninges
41
N. gonorrhea attaches to
columnar and transitional epithelia (pili) - mucosal membranes of the genital tracts, rectum and nasopharynx
42
Neisseria gonorrhea lacks
true polysaccharide capsule and doesn't cause many of the vascular/DIC problems that meningococci cause
LOS instead of LPS
43
Neisseria gonorrhea has
IgA protease
44
Neisseria gonorrhea causes
gonorrhea, cystitis; can also cause suppurative arthritis (knees, ankles)
45
Pathology of Neisseria gonorrhea
suppurative inflammation of mucosal surfaces and subepithelial tissues; grossly purulent lesions and discharge
46
Important points about Haemophilus influenzae
upper respiratory, sinusitis/otitis, meningitis (pneumonia)
| severe disease, including meningitis most commonly seen in young children
47
Non-invasive H. influenzae
upper respitatory, sinusitis/otitis
| most forms causing common upper respiratory symptoms are unencapsulated
48
Which capsule type for H. influenzae is the most common causing invasive disease?
type b
49
characteristics of (H. influenzae) type b capsule
endotoxin characteristics, causing DIC
| more resistant to complement cytotoxicity
50
H. influenzae infects through
respiratory route - inhalation of infected droplets from active cases and carriers
51
H. influenzae noninvasive local disease due to
local overgrowth of colonizing non-encapsulated forms secondary to other pathologic conditions (viral obstruction)
52
Invasive (type b) H.influenzae disease causes
meningitis, pneumonia, epiglottitis
53
Invasive (type b) disease likely secondary to
dissemination through blood stream
54
window of susceptibility for invasive disease (type b)
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
why is the H. influenzae vaccine conjugated?
infants make poor antibody responses to the capsule polysaccharides; however, by conjugating the polysaccharides with protein, the conjugated vaccine is effective in infants
56
H. parainfluenzae
normal flora of the mouth
| may result in endocarditis
57
H. ducreyi
chancroid
58
M. catarrhalis ithe 3rd most common cause of
secondary bacterial infections such as sinusitis and otitis media
59
What does Moraxella catarrhalis have?
lipopolysaccharide exotoxin similar to Neisseria; rarely causes septicemia and meningitis
60
Infections of childhood often associated with?
unprotected window between loss of maternal IgG and self IgG/IgA production
61
Bordetella pertussis has a strong tropism for
brush border; exotoxin leads to local ciliary paralysis with secondary inflammation
62
Whooping Cough vaccine
DTP vaccine; immunization leads to production of antibody to the exotoxin
63
Pathology of Corynebacterium diphtheria
ulcerative lesions of the respiratory mucosa; leads to coagulative exudate and formation of "pseudomembrane"
64
Corynebacterium diphtheria extoxin leads to
fatty myocardial changes, myofiber necrosis, and polyneuritis
causes toxicity by inhibiting protein synthesis
65
General characteristics of gram negative rods
1. endotoxins: lipopolysaccharides
2. frequent drug resistance
3. has replaced pyogenic cocci as bulk of hospital-acquired and opportunitistic infections
66
When does E. Coli cause disease
when they gain access to tissues (peritoneum, urinary tract, sepsis) or secondary to tissue inflammation in abdomen (appendicitis, obstruction)
67
Types of infection caused by E. Coli
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
Suppurative infections of the abdominal cavity can be:
secondary to obstruction: appendicitis, cholecystitis, diverticulitis
performation, trauma (including surgery)
69
Klebsiella pneumonia associated with
aspiration in a hospital setting
70
Proteus mirabilis
UTI/pyelonephritis; pneumonia (debilitated patients)
71
Serratia marcescens
pneumonia (debilitated patients)
72
Pseudomonas aeruginosa
rod-shaped gram negative; motile, flagellum, aerobic, non-spore forming
73
Pseudomonas aeruginosa contains
fluoroscein pigment - pyocyanin and pyoverdin
74
Where is pseudomonas
ubiquitous in hospitals - cultured extensively from surfaces in hospitals
75
What immune response protects from an pseudomonas infection?
phagocytosis
76
Pseudomonas is a frequent deadly pathogen in patients with
cystic fibrosis, severe burns, or neutropenia
77
psuedomonas is characterized by
necrotizing inflammation
vasculitis with abundant organisms
BLUE HAZE
78
Pseudomonas virulence factors
```
endotoxin - LPS
extotonix A similar to diphtheria
protective exopolysaccharide (biofilms)
phospholipases
Fe-containing compounds toxic to endothelial cells
leukocidin
```
79
Pseudomonas lung infections
fulminant pneumonias
80
Other forms of pseudomonas infections
corneal keratitis in wearers of contact lenses
endocarditis and osteomyelitis in IV drug users
external otitis
severe external otitis in diabetics
81
Anaerobic gram-negative bacterial infections
Bacteroides
Fusobacterium
Peptococcus
Peptostreptotoccus (gingival infections)
82
foul-smelling pus and mixed-infections associated with
anaerobic gram-negative bacterial infections
83
Legionella
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
Helicobacter pylori
spiral/helical gram negative, motile, urease
| commonly found in antrum
