Micro -- LRT Flashcards
1
Q
Chest pain, hacking cough w/ some sputum production, fever, after signs of common cold, no infiltrate on CXR
A
bronchitis
2
Q
causes bronchitis
A
Usually viral (if >14 days - id bacteria) rhinovirus, paramyxovirus, adenovirus, influenza c, coxsackievirus, RSV
3
Q
bacterial causes for bronchitis
A
mycoplasma pneumoniae, chlamydia pneumonia
4
Q
bronchiolitis
A
inlammation of bronchial tree as low as bronchioles - usually in infants younger than 1 yr
RSV, paramyxovirus, adenovirs
5
Q
pertussis phases
A
incubation period (3-21 days) catarrhal stage = cold sxs (1-2 weeks) paroxysmal stage = severe and uncontrollable coughing convalescent phase = bacteria decreasings, still coughing
6
Q
pertussis toxin
A
AB toxin – results in high levels of cyclic AMP and lots of mucus production. In that way similar to Diptheria. Tracheal cytotoxin kills ciliated cells. Antibiotics primarily effective in catarrhal stage only.
7
Q
culture pertussis on
A
bordet-gengou agar, regan-lowe now
or direct fluorescent ab test
8
Q
what do flu vaccines target
A
NA cleaving of HA/SA that permits viral spread
multiples strains of A but also against B
9
Q
minor changes in antigens occur due to gene mutation in influenza virus.
A
antigenic drift (a and B)
10
Q
major changes in antigens occur due to gene reassortment in influenza virus.
A
antigenic shift (A)
11
Q
flu strains named after
A
HA protein (16) and NA proteins (9) – A
12
Q
influenza can predispose to
A
pneumonia!
s. aureus, H. influ, S. pneumo, S. pyo
13
Q
most common cause of pneumonia
A
S. pneumo
14
Q
S. pneumo characteristics
A
Bacteria - gram + - diplococci - catalase negative – alpha hem (green) - bile-eschulin neg - optochin susceptible = s. pneumo
15
Q
Bacteria - gram + - diplococci - catalase negative – alpha hem (green) - bile-eschulin neg - optochin susceptible
A
S. pneumo
16
Q
Common causes of pneumonia in 18-40
A
Mycoplasma
C. pneumoniae
S. pneumoniae
17
Q
Common causes of pneumonia in 40-65
A
S. pneumoniae
H. influenzae
Legionella
Anaerobic bacteria
viruses
18
Q
Common causes of pneumonia >65
A
S. pneumoniae
Gram (-) rods
H. influenzae
viruses
anaerobic bac
19
Q
pneumonia in kids
A
RSV
parainfluenza virus
20
Q
S. agalactiae characteristics
A
bacteria gram + cocci catalase - beta hemo bacitracin resistant S. ag (Group B strep)
21
Q
bacteria gram + cocci catalase - beta hemo bacitracin resistant
A
S. agalactiae
22
Q
Nocardia asteroides characteristics
A
Gram +
Beaded filaments
Weakly acid fast
obligate aerobe
23
Q
Gram +
Beaded filaments
Weakly acid fast
obligate aerobe
A
N. asteroides
24
Q
sputum color - s. pneumo
A
rust colored
25
sputum color - pseudomonas, haemophilus, pneumococcal
green
26
klebsiella sputum
red currant jelly
27
abaerobic sputum
foul-smelling, bad tasting
28
characteristics TB
acid fast
aerobic
bacilli
fastidious (3-8 weeks)
29
pneumonia neonates
S. agalactiae (group B)
| E. coli
30
children pneumonia
viruses (RSV)
M. pneumoniae
C. pneumoniae
S. pneumoniae
31
nosocomial pneumonia
```
Gram - rods
staph aureus (drug resistant)
```
32
Immunocompromised
```
Gram (-) rods
Streptococcus pneumoniae
Fungi
Filamentous bacteria
Pneumocystis jiroveci (CD4<200)
Viruses
```
33
Aspiration pneumonia
anaerobes
34
alcholics pneumonia
Streptococcus pneumoniae
Klebsiella pneumoniae
Anaerobes
35
IV drug use pneumonia
s. aureus
36
Post viral secondary infection pneumonia
s. aureus
37
chronic steroids pneumonia
nocardia spp.
38
clinical presentation influ A/B
common cold, flu (leads to primary viral or secondary bacterial pneumonia)
39
Influ A and B pathology
Inhaled through aerosols. Infects the larynx mucosa via contact of the viral hemagglutinin (HA) envelope protein with sialic acid on cell surfaces (leads to endocytosis). The viral neurominidase (NA) envelope protein is important for cleaving HA bound to sialic acid, this permits viral spread. Virus replication in host cells can lead to death of the host cell leading to tissue damage and disease. The immune response to infection also contributes to disease via production of IL-1 and IFN-γ.
40
S. agalactiae clinical presentation
neonatal meningitis, neonatal pneumonia, neonatal sepsis
41
pathology s. aga
bacteria is carried in the maternal genital tract. Can colonize the neonate following obstetric complications. Causes meningitis (develops weeks after birth) or pneumonia (develops within a day after birth).
42
dx s. aga
Gram stain of CSF, urine, blood. Gram (+), β-hemolytic, bacitracin resistant.
43
tx s. aga
penicillin g
44
m. pneumo has no
cell wall (no gram stain)
45
m pneumo most commonly affects
people in close quarters (dorms)
46
clinical presentation m. pneumiae
tracheobronchitis, atypical pneumonia (walking pneumonia)
47
pathology m. pneumoniae
Only infects humans. Transmitted by respiratory droplets. Adheres to respiratory epithelium, inhibits ciliary motion and destroys mucosa. Infection leads to localized inflammation. B-cell response can generate antibodies that may autoreact with erythrocytes (IgM cold agglutinins), brain, and heart. Can lead to arthritis.
48
dx m. pneumoniae
Presence of cold hemagglutinin, no cell wall, fried egg appearance, serology.
49
tx m. pneumoniae
Erythromycin or tetracycline.
50
tetracycline mechanism
Bind 30S to prevent attachment of aminoacyl-tRNA (elongation)
51
Clamydia pneumoniae most often infects
young adults
52
clincial presentation chlamydiae pneumo
atypical pneumo
53
c. pneumoniae pathology
community-acquired. Microorganism is an obligate intracellular parasite and enters the upper respiratory tract epithelium and becomes phagocytosed by macrophages. Lymphocytes infiltrate site of infection leading to local pulmonary edema, necrosis, and hemorrhage. Two life-forms: extracellular (EB), and intracellular (RB). EB is the infective form.
54
dx c. pneumo
Giemsa stain to visualize intracytoplasmic inclusions. Serology.
55
tx c. pneumo
doxycycline
56
S. aureus clinical presentaiton
Local = skin/subcutaneous: impetigo, cellulitis, folliculitis, furuncles, carbuncles. Respiratory: pneumonia with cavitations. Systemic = acute endocarditis, meningitis, osteomyelitis, septic arthritis.
57
pathology s. aureus
Bacteria colonize skin (following breach) or nasopharynx (following intubation or viral infection) → overgrow and evade host defenses using protein A, coagulase, hemolysins, and leukocidins. Neutrophils localize to site of infection → purulent abscesses form → skin/subcutaneous infections or pneumonia results. Deeper invasion into the bloodstream relies on the hyaluronidase, staphylokinase, and lipase virulence factors.
58
dx s. aureus
Gram + clusters, catalase +, coagulase +
59
tx s. aureus
antibiotic treatment is with either penicillinase-resistant penicillins or vancomycin
60
vancomycin moa
Bind D-al-D-al of cell wall precursor inhibit release from bactoprenol carrier, inhibiting peptidoglycan cell wall synthesis -- translgycosylase
61
penicillinase-resistant penicillins
Nafcillin, Dicloxacillin
62
legionella pneumophila clinical presentation
pontiac fever
| Legionnaire's disease (atypical pneumonia)
63
pathology legionella
Naturally inhabits water reservoirs. Inhaled through aerosols from respiratory devices, air conditioners. Adheres to respiratory epithelium via pili. Phagocytosed by alveolar macrophages. Survives and proliferates inside the macrophage. Infected macrophages secrete neutrophil chemoattractants which can lead to Pontiac fever (acute illness lasting 2-5 days) or Legionnaire’s disease (neutrophils arrive from microabscesses which can be seen on x-ray which leads to sever atypical pneumonia).
64
dx legionella
Gram stains poorly, best visualized with silver stain.
Culture on charcoal yeast extract with iron and cysteine.
Urinary antigen detected by radioimmunoassay.
Serology.
65
tx legionella
erythromycin
66
erythromycin moa
Bind 23S of 50S to prevent translocation - Binds to 50S ribosomal RNA near the peptidyltransferase center blocking peptide chain elongation.
67
begin prophylaxis for PCP when
CD4 < 200
68
pathology PCP
cyst inhaled by most in childhood leading to asymptomatic or mild pneumonia. Stays latent in the lungs. In immunocompromised hosts it exhibits uncontrolled growth leading to an inflammation response that then leads to pneumonia.
69
dx pcp
silver stain of induce sputum. Bronchoalveolar lavage or lung biopsy. Cysts forming dark oval bodies.
70
tx pcp
TMP-SMX or pentamidine
71
mechanism TMP-SMX
PABA analog - acts as comp inh for dihydropteraste sythetase
inhibits bacterial hihydrofolate reductase
run out of purines
72
mycobacterium tuberculosis clinical presentation
hemoptysis, fever, weight loss, fatigue
73
Nocardia asteroides clinical presentation
pneumonia, abscesses in the kidney and the brain
74
pathology n. asteroides
Found in the soil and inhaled followed by phagocytosis. Mycolic acid in the cell wall allows for intracellular survival and proliferation. Caseous granulomas wall off infectious particles. Pneumonia and cavatations form. May spread via the blood to adjacent tissue to form abscesses in the kidney and brain.
75
dx n. asteroides
Gram (+), aerobic, beaded filaments, weakly acid-fast.
76
tx n. asteroides
TMP-SMX, surgical drainage of abscesses.
