3- microbiology of respiratory tract Flashcards

1
Q

what are the 3 important components for disease? (another triangle thing)

A

susceptible host, virulent pathogen, favorable environment = if lack any of these then disease

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2
Q

what are the 6 components of chain of infection? (geography thing)

A
  • susceptible host (elderly, infants, immunocompromised)
  • portal of entry (mouth, eyes, cuts)
  • mode of transmission (contact, droplets (sneeze, speak, cough))
  • portal of exit (mouth, cuts, feces, bodily fluids)
  • reservoir (people, animals, water, food, soil)
  • agent (bacteria, virus, parasites, funghi)
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3
Q

what is a colonisation?

A

presence of microbe in human body without inflammatory response

*means doesn’t need antibiotic

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4
Q

what is a bacteraemia?

A

presence of viable bacteria in blood

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5
Q

what is infection?

A

inflammation due to viable bacteria in blood

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6
Q

what is sepsis?

A

dysregulated host response due to infection

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7
Q

what is importance if it says colonies in question?

A

it’s a trick - make sure to not prescribe antibiotics when colony as colony is just presence of microbe but not actually causing inflammatory response

*unless in immune compromised/CF

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8
Q

what are some common bacteria causing community acquired pneumonia? (from highest incidence to lowest incidence)

A
  1. streptococcus pneumoniae = typical
  2. haemophilus influenzae
  3. mycoplasma pneumoniae = atypical
  4. chlamydia pneumoniae = atypical
  5. legionella species = atypical
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9
Q

what are common hospital acquired pneumonia and Ventilator-Associated Pneumonia?

A
  1. staphylococcus aureus
  2. pseudomonas aeruginosa
  3. e.coli

*a bunch more in notes but just picked these - ones with more gram negatives

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10
Q

what is common fungal infection in lungs?

A

aspergillus

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11
Q

what are some common viral infections in adults?

A
  • influenza viruses
  • rhinoviruses
  • coronavirus
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12
Q

what is involved in diagnosing infections? (sam as like everything else)

A
  • history
  • examination
  • investigations (radiology, biochemistry, immunology etc)
  • tests (blood, stool, urine, wound, tissue cultures)
  • serology
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13
Q

what is problem with serology test? why is it not that useful for someone who is acutely ill?

A

takes a long time for body to form antibodies

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14
Q

what is
a) sinusitis?
b) rhinitis?
c) pharyngitis?
d) epiglottitis?
e) laryngitis?

A

inflammation of:
a) paranasal sinuses
b) nose
c) pharynx, tonsils, uvula
d) epiglottis, superior larynx
e) larynx

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15
Q

what is the important aspects of inflammation that are good to think about for different locations e.g. pleuritic chest pain, coughing, short of breath, maybe sputum?

A

calor (heat), rubor (redness), tumor (swelling) , dolor (pain) , functio laesa (loss of function)

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16
Q

how long does blood culture and PCR take? what is the significance of this?

A

blood test about 2 days and PCR about 6-24 hours but often lab doesn’t run every day so logistics mean maybe only done once or so a week

= means that you can’t just wait until diagnosis before doing something, need to treat as go along and with little bits and pieces your told

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17
Q

what are the key things to do for microbiology?

A
  • identify what particular infection for particular patient
  • determine colonisation vs infection for interpreting test results
  • identify organism with name & characteristics and with correct tests
  • choose treatment - with antibiotic guide & formulation, adverse effects
  • prevent infection = vaccines, drugs
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18
Q

what are people have unusual host response?

A
  • old people
  • immunosuppressed
  • some drugs, genetic
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19
Q

what are characteristics of unusual microbe that make difficult infection?

A
  • virulence expression
  • latency – intracellular
  • predilection (preference) for certain sites
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20
Q

what are the different classes of beta lactams?

A
  • Penicillin
  • Flucloxacillin
  • Amoxicillin
  • Cephalosporins
  • Piperacillin/tazobactam
  • carbapenems
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21
Q

does flucloxacillin work for methicillin resistant?

A

no

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22
Q

why is it bad for people with penicillin allergies?

A

because it means they might have to use drugs such as quinolones which is bad with lots of bad side effects
= that’s why it’s important to test if actually allergic cause you don’t want to give someone bad drug unless you really need to

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23
Q

what are important things to think about when picking what antibiotic to give?

A
  • dose, route, frequency, cost
  • age, body composition
  • with food/without food
  • if they can access treatment
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24
Q

how many days of antibiotics is suitable?

A

5 days

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25
Q

what is risk factor clue for question of community acquired penumonia?

A

smoker

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26
Q

what are clinical symptoms of community acquired pneumonia?

A
  • cough
  • increased sputum
  • dyspnoea
  • chest pain
  • fever
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27
Q

what is seen on chest xray in community acquired pneumonia?

A

chest xray with infiltrates

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28
Q

what is temperature and results found from examination of community acquired pneumonia?

A

temperature 38.0, left base crackles

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29
Q

what is pathology of community acquired pneumonia?

A

organism reaches lung → immune activation & infiltration (systemic response) →fluid & cellular build up in alveoli leads impaired gas exchange

30
Q

what is aspiration pneumonia?

A

occurs when food or liquid is breathed into the airways or lungs, instead of being swallowed so lots of oral pathogens in wrong way = anaerobes

31
Q

what are some bugs common in pneumonia in immunosuppressed?

A
  • Pneumocystis jiroveci, Aspergillus sp. , endemic mycoses
  • Mycobacterium tuberculosis , non-tuberculous mycobacteria
32
Q

what tests should be done to help diagnosis of community acquired pneumonia?

A
  • sputum culture
  • purulence
  • viral PCR
33
Q

what are risk factors for community acquired pneumonia?

A
  • increasing age
  • immunocompromised/suppressed patients
  • smoking
34
Q

who is more likely to have asymptomatic strep?

A
  • child
  • also military personal
35
Q

what are strep pneumoniae virulence factors? what is the main one?

A

capsule = key virulence factor, basis of where vaccination comes from (capsule also anti-phagocytic)

other virulence factors = surface adhesins, pneumolysin, sIgA protease

36
Q

what are the different ways streptococcus pneumoniae presents?

A
  • pneumonia is most common presentation
  • can also present as otitis media, bacteraemia, meningitis
37
Q

should you start antibiotics in absence of evidence of bacterial infection?

A

no

38
Q

how should you start treatment of strep pneumoniae?

A

first treatment = empiric therapy

  • you take history of relevant allergies
39
Q

what antibiotic is prescribed for mild to moderate community acquired pneumonia?

A

amoxicillin - if penicillin allergy doxycycline (tetracycline)

40
Q

what antibiotic is prescribed for severe community acquired pneumonia?

A

co-amoxiclav + doxycycline - if penicillin allergy IV levofloxacin (quinolone)

*if in ICU - add clarithromycin

41
Q

what antibiotic is prescribed for severe hospital acquired pneumonia?

A

amoxicillin + metronidazole + gentamicin (aminoglycoside)

  • if penicillin allergy, co-trimoxazole, metronidazole, gentamicin
42
Q

what antibiotic is prescribed for non-severe hospital acquired pneumonia?

A

amoxicillin + metronidazole

  • if penicillin allergy = co-trimoxazole + metronidazole
43
Q

what are the 4C antibiotics?

A
  1. ciprofloxacin (fluoroquinolone)
  2. clindamycin
  3. cephalosporin
  4. co-amoxiclav
44
Q

what is invasive pneumococcal disease?

A

a group of illnesses caused by pneumococcus bacteria e.g. meningitis & bacteraemia

45
Q

when should you add vancomycin?

A

if recent travel to country with high rates of penicillin resistant pneumococci

46
Q

how can pneumonia infection cause empyema?

A

accumulation of infected liquid can breach the lung and get within body cavity especially pleural space causing empyema

47
Q

what is recent holiday to foreign country in history a hint for?

A

legionella pneumonia - can test with legionella urinary antigen (detects serogroup 1 only)

48
Q

what tests should be done for legionella pneumonia?

A
  • PCR from sputum
  • legionella urinary antigen
  • culture
49
Q

what is treatment of legionella pneumonia?

A

clarythromycin or erythromoycin
and if needed (but very last resort) quinolones e.g. levofloxacin

50
Q

is legionella gram negative or gram positive?

A

gram negative

51
Q

where is legionella?

A

in moderately warm water - why back from travel is a clue

52
Q

how is legionella transmitted?

A

Transmitted by inhalation of contaminated water droplets

53
Q

what are symptoms of legionella?

A

severe flu and can include fever, chills, loss of appetite, headache, lethargy

54
Q

what are typical symptoms of mycoplasma pneumonia?

A

typically young student, aches & pains, feels rubbish, headache, noticed a rash (all sorts of rashes), non productive cough, often self limiting

55
Q

what are the main diagnostic tests in legionella?

A
  • culture
  • urinary antigen test
  • nucleic acid-based detection

from different places - respiratory tract specimens, blood, urine

56
Q

what is treatment of mycoplasma pneumonia?

A

= has no cell wall →amoxicillin NOT treatment of choice

  • clarithromycin and if not ciprofloxacin
57
Q

when does staphylococcus aureus pneumonia occur?

A

post influenza - spreads haematogenous (lymphatic spread)

58
Q

what is the drug of choice for staphylococcus aureus pneumonia?

A

co-trimoxazole then doxycycline

59
Q

what is whooping cough (pertussis)?

A
  • Acute tracheo-bronchitis
  • cold-like symptoms and paroxysmal coughing for two weeks
  • repeated violent exhalations with severe inspiratory whoop, vomiting common
  • residual cough for month or more, infectious in first fortnight and then not infectious
60
Q

what is bacteria causing whooping cough?

A

bordetella pertussis = gram negative coccolbacillus

61
Q

what antibiotic should be given for someone presenting with acute bronchitis - infection & inflammation of bronchi, productive cough, wheeze and normal chest examination & x-ray?

A

NO ANTIBIOTICS = trick - when normal chest examination + chest x-ray shouldn’t give antibiotics

62
Q

does every COPD examination need antibiotics?

A

no

63
Q

can resistance spread?

A

when encountered resistance - bacteria chat to each other and swap resistance elements so more likely to get resistance to lots of things (many mechanisms)

64
Q

what are some viruses which cause pneumonias?

A

influenza, RSV (respiratory syncytial virus), adenovirus (in transplant patients), corona virus, measles

65
Q

what are examples of evasion?

A
  • hide in neurons and non-neuronal cells
  • bukholderia pseudomallei can emerge many years later
  • leishmania can interfere with IL-12 transmission

= not too important to know details, just idea

66
Q

who are more vulnerable to aspergillus?

A

people who’ve had transplant or chemo more vulnerable or HIV infection

67
Q

what is aspergillus?

A

fungus that can cause pneumonia

68
Q

what cells are involved in bacterial infection?

A

dependant on antibodies so needs phagocytes + neutrophils to clear things and B cells to make the antibodies

69
Q

what cells are involved in virus infections?

A

managed by T lymphocytes mainly - also antibodies + B lymphocytes important for detection but clearance is purely T lymphocyte

70
Q

what cells are involved in fungal infections?

A

needs phagocytosis to clear so eosinophil and T lymphocytes (mainly) so predisposed if not phagocyte function or T lymphocytes (chemo + HIV more susceptible)