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IBI Test 1 > B3.014 Pulmonary Pathogens > Flashcards

B3.014 Pulmonary Pathogens Flashcards

1
Q

who is susceptible to opportunistic pneumonia?

A

immunocompromised patients

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2
Q

what types of pneumonia are typically caused by bacteria?

A

CAP and HAP

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3
Q

what are the primary bacteria that cause pneumonia?

A

streptococcus pneumoniae
mycoplasma pneumoniae
legionella pneumophila

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4
Q

what types of pneumonia are typically caused by viruses?

A

opportunistic (pediatric/geriatric)

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5
Q

what are the primary viral causes of pneumonia?

A

flu a and b, parainfluenza virus, respiratory syncytial virus (RSV)

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6
Q

what type of pneumonia are typically caused by fungi?

A

opportunistic (immunosuppressed, AIDS, cancer therapy, transplants)

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7
Q

hemolytic properties of s. pneumoniae

A

alpha hemolytic

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8
Q

what type of capsule surrounds s. pneu?

A

carbohydrate

>90 sertoypes

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9
Q

what does it mean to be naturally competent for DNA transformation?

A

has the ability to mutate by taking up DNA from plasmids to make itself more pathogenic

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10
Q

discuss the classification of streptococci

A 
gram +
chains
normal flora of skin and mouth
catalase negative
may produce exotoxins
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11
Q

what types of strep are B hemolytic?

A

group A strep (GAS) : s. pyrogenes

group B strep (GBS) : s. agalactiae

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12
Q

what types of strep are alpha hemolytic?

A

viridans (green) strep: s. mutans

s. pneumoniae

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13
Q

what types of strep are gamma hemolytic?

A

enterococcus (GDS)

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14
Q

who hosts s.p.?

A

humans

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15
Q

where is asymptomatic carriage of s.p. common?

A

nasopharyngeal mucosa
5-75% of population
considered a commensal

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16
Q

how does transmission of s.p.?

A

respiratory droplets

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17
Q

how do most cases of s.p. arise?

A

spread of endogenous organisms

our own natural flora gets into the wrong niches

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18
Q

other than pneumonia, what common illnesses develop as a result of s.p.?

A

sinusitis, otitis media, meningitis

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19
Q

what are predisposing factors for getting s.p?

A

respiratory viral infections

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20
Q

what is pneumonia?

A

aspiration of bacteria and replication in alveolar spaces

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21
Q

how long is the incubation period of pneumonia?

A

1-30 days

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22
Q

what are symptoms of pneumonia?

A

abrupt onset of fever and shaking chills

pleurisy, productive cough, blood tinged sputum

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23
Q

risk factors for pneumonia

A

antecedent viral infection of resp tract, especially influenza
smoking
age <2 or >65
hematological disorders, asplenia, chronic pulmonary disease, diabetes, renal

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24
Q

how can you differentiate typical vs atypical pneumonia?

A 
based on symptoms
atypical "walking" pneumonia:
-slow onset
-moderate fever
-non-productive cough
-headache
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25
key atypical pneumonia pathogens
``` chlamydia pneumoniae legionella pneumonia mycoplasma pneumonia chlamydia psittaci coxiella burnetii some viruses ```
26
describe meningitis
100% mortality without antibiotic treatment 25% with treatment inflammation frequently leads to permanent brain damage, blindness, hearing loss, learning disabilities
27
describe otitis media and sinusitis caused by s.p.
50% of middle ear infections sinusitis occurs in all age groups can develop into megingitis
28
virulence factors of s.p.
polysaccharide capsule | C polysaccharide
29
describe the s.p. polysaccharide capsule
90 serotypes essential for pathogenesis anti phagocyctic immunogenic
30
describe the s.p. C polysaccharide
complex of phosphorylcholine, peptidoglycan and teichoic acid common to all serotypes present in urine and serum during infection
31
what toxins are associated with s.p.
pneumolysin autolysin IgA protease
32
describe pneumolysin
cholesterol dependent pore forming toxin toxic to bronchial epithelial cells activates classical complement pathway
33
describe autolysin
binds to cell wall degrades peptidoglycan, resulting in bacterial cell lysis releases pneumolysin from cell releases cell wall components that activate the inflamm response antibodies to autolysin can be protective
34
describe IgA protease
blunts mucosal adaptive immune response
35
what are other characteristics of s.p. culture other than hemolysis/shape/catalase neg
bile solube optochin-sensitive Quellung (swelling) reaction: shows capsule on bacteria
36
where can C polysaccharide be found?
urine and serum
37
how is capsular antigen detected?
latex agglutination assap
38
what MIC values are considered susceptible?
<2 ug/ml
39
what MIC values are considered resistant?
>8 ug/ml
40
DOC for pneumonia
penicillin (for sensitive isolates); vancomycin or fluoroquinolone + 3rd gen cephalosporin
41
PPSV23 (Pneumovax)
pneumococcal polysaccharide vaccine covers most bacteremic strains (23) capsular type-specific antibody is protective recommended for: adults >65, chronically ill, and immunocompromised kids >2 years
42
PCV7 (Prevnar)
pneumococcal conjugate vaccine capsular antigens from 7 serotypes conjugated to a mutated diphtheria toxin immunogenic in children and infants recommended for all children <2 and at risk <6
43
PCV13 (prevnar13)
capsular antigens from 13 serotypes conjugated to a mutated diphtheria toxin children 6-17 adults >50
44
describe the classification of legionella pneumophila
gram negative bacillus does not stain well motile, catalase positive fastidious
45
what does l. p. require to grow?
L-cysteine ferric ions pH 6.9
46
how is l.p. transmitted?
``` environmental pathogen no person to person transmission found in water and soil intracellular symbionts of amoebae inhalation of aerosols containing infection organisms ```
47
common sources of l.p
``` air conditioning cooling towers medical respiratory equip showers whirlpools humidifiers ```
48
when are legionella outbreaks most common
late summer-fall
49
risk factors for legionella
``` advanced age smoking heavy alcohol use transplant recipients immunocompromised (diGeorge) ```
50
what is l.p.'s mechanism of action
infect alveolar macrophages -MOMP (major outer membrane protein): binds C3 and facilitates entry into macrophages bacterial replication in phagosomes using T4SS effectors to block acidification/fusion with lysosomes -"replicative vacuoles" surrounded by ER
51
virulence factors of l.p.
hemolysin: tissue degradation, lysis of RBCs phospholipases: vacuolar escape, surfactant degradation
52
incubation period of l.p.
2 to 14 days
53
symptoms of l.p.
``` moderate fever headache slight or non-productive cough fatigue anorexia GI symptoms hyponatremia ```
54
l.p mortality rate
15-20% | sporadic disease that is frequently misdiagnosed
55
main difference between Pontiac fever and legionella pneumonia
Pontiac fever 0% fatality | higher attack rate but hospitalization uncommon
56
gold standard for l.p. identification
culture: growth on buffered charcoal year extract (BCYE) agar only legionella urine antigen: detects only serotype 1 L. pneumophila (majority of infections)
57
antibiotics that achieve high intracellular concentration against l.p.
IV fluoroquinolones | IV azithromycin
58
how to prevent legionella
``` identification of source increase water temp hyperchlorination removal or scale from water tanks routine monitoring ```
59
describe the features of mycoplasma
``` smallest free living organisms slow growth (1-6 hours) lack cell walls: -cell membranes contain sterols -pleomorphic (different shapes) ```
60
what diseases results from mycoplasma pneumoniae?
atypical pneumonia tracheobronchitis mild upper respiratory infections joint infections
61
m. p. cell shape
``` intracellular network of protein filaments cytadhesin organelle (arrow): membrane bound cylindrical extension at one pole that penetrates membrane and binds respiratory epithelial cells ```
62
spread of m.p
respiratory secretions
63
incubation time of m.p.
1-3 weeks
64
when are infection rates of m.p. highest?
crowded conditions frats, dorms, schools older children, adolescents, young adults and HIV patients most susceptible
65
pathogenesis of teacheobronchitis and pneumonia
1. binding of ciliated respiratory epithelial cells 2. production of phospholipases and peroxides 3. ciliostasis, leakage of epithelial cells 4. infection of lower resp tract 5. IL-1, TNF a 6. influx of PMNs, T and B cells
66
m.p. symptoms
``` headache fever pharyngitis dry, nonproductive cough no elevation of WBCs bilateral, diffuse infiltrates skin rash ```
67
how long does m/p/ last
4-6 weeks
68
m. p. culture characteristics
medium must contain serum or cholesterol colony formation in 206 weeks mulberry/fried egg like colonies
69
m. p. serological tests
cold agglutinin assay complement fixation assay ELISA for IgM/IgG PCR- gold standard
70
what antibiotics are mycoplasma resistant to?
penicillins cephalosporins glycopeptide antibiotics -all cell wall inhibitors
71
drugs of choice for m.p.
tetracyclines macrolides fluoroquinolone
72
what causes influenza
influenza virus
73
what causes croup
parainfluenza virus
74
what causes bronchiolitis
RSV
75
what causes bronchopneumonia
influenza virus, RSV, adenoviruses
76
main virulence factors of influenza
``` Hemagglutinin -18 subtypes -sialic acid receptor Neuraminidase -11 subtypes -sialidase M2 ion channel -sense acidification in the endosome M1 protein -structural NP NS1 -reprograms host cell to replicate ssRNA ```
77
symptoms of the flu
``` acute febrile self limited headache malaise myalgias nasal obstruction discharge sore through cough ```
78
flu attack rate
10-40%
79
when is the flu virus stable
low humidity and cool temps
80
what is desquamation of mucus secreting and ciliated cells
cilia and mucous are disintegrated resulting in a loss of defense against respiratory infections likely a cause of secondary infections
81
mediators of flu cytokine storm
``` IL-6 -fever, acute phase response -secreted by macrophages TNF-a -causes fever and cachexia IFN a/b IL-1 -produced by macrophages -proinflamm and fever inducing IFN-y -innate and adaptive immunity -produced by lymphocytes ```
82
what cytokines induce the antiviral state
IFN a/b
83
what type of genetic mutation results in antigenic drift
point mutations in H and N
84
what type of genetic mutation results in antigenic shift
major change in H (sometimes N) | genetic reassortment
85
what family do RSV, hMPV, and parainfluenza virus belong to?
paramyxoviruses
86
describe paramyxoviruses
enveloped pleomorphic virions contain non-segmented negative ssRNA induce syncytia (multinucleated cells)
87
general paramyxoviridae structure
``` attachment proteins differ between viruses -parainfluenza/mumps: HN protein -measles- H glycoprotein -RSV- G glycoprotein all have F (fusion) protein ```
88
where does DNA replication occur for paramyxoviridae?
outside of the nucleus
89
when do RSV epidemics occur?
winter
90
who is at risk of RSV?
#1 cause of bronchiolitis and pneumonia in children <1 in the US -congenital heart disease, bronchopulm dysplasia, immunodeficiency significant cause of resp disease in older adults -stem cell transplants, severe heart disease, COPD
91
RSV symptoms
fever chills cough, congestion, coryza, rhinorrhea, conjunctivitis bronchiolitis- wheezing, shortness of breath pneumonia apnea spells in infants
92
RSV diagnosis
rapid antigen detection from aspirates RT-PCR from bronchial washes culture difficult and too slow
93
RSV treatment
``` supportive care -fluids and resp support aerosolized ribavirin -severely immunocompromised humanized monoclonal anitbodies -protect at risk infants no vaccine ```
94
describe hMPV
human metapneumovirus causes 5-20% of pediatric URIs and LRTIs (serology) -90% of people have it by 5, 100% by adulthood clinical symptoms indistinguishable from RSV supportive treatment
95
parainfluenza virus features
5 serotypes reinfection common negative ssRNA enveloped virus
96
pathogenesis of parainfluenza
cause illness in the large airways of the lower resp tract - tropism for ciliated epithelial cells - croup, bronchiolitis, also pneumonia
97
immune response to parainfluenza
``` humoral -neutralizing antibody to surface proteins -mucosal IgA can help prevent infection cellular -cytotoxic T cells ```
98
who is susceptible to parainfluenza
severe disease in adults and peds w hematopoietic stem cell or solid organ transplants

IBI Test 1 (15 decks)

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