3- microbiology of respiratory tract

Question 1

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

Answer 1

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

Question 2

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

Answer 2

• 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)

Question 3

what is a colonisation?

Answer 3

presence of microbe in human body without inflammatory response

*means doesn’t need antibiotic

Question 4

what is a bacteraemia?

Answer 4

presence of viable bacteria in blood

Question 5

what is infection?

Answer 5

inflammation due to viable bacteria in blood

Question 6

what is sepsis?

Answer 6

dysregulated host response due to infection

Question 7

what is importance if it says colonies in question?

Answer 7

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

Question 8

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

Answer 8

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

Question 9

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

Answer 9

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

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

Question 10

what is common fungal infection in lungs?

Answer 10

aspergillus

Question 11

what are some common viral infections in adults?

Answer 11

• influenza viruses
• rhinoviruses
• coronavirus

Question 12

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

Answer 12

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

Question 13

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

Answer 13

takes a long time for body to form antibodies

Question 14

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

Answer 14

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

Question 15

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?

Answer 15

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

Question 16

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

Answer 16

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

Question 17

what are the key things to do for microbiology?

Answer 17

• 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

Question 18

what are people have unusual host response?

Answer 18

• old people
• immunosuppressed
• some drugs, genetic

Question 19

what are characteristics of unusual microbe that make difficult infection?

Answer 19

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

Question 20

what are the different classes of beta lactams?

Answer 20

• Penicillin
• Flucloxacillin
• Amoxicillin
• Cephalosporins
• Piperacillin/tazobactam
• carbapenems

Question 21

does flucloxacillin work for methicillin resistant?

Answer 21

no

Question 22

why is it bad for people with penicillin allergies?

Answer 22

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

Question 23

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

Answer 23

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

Question 24

how many days of antibiotics is suitable?

Answer 24

5 days

Question 25

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

Answer 25

smoker

Question 26

what are clinical symptoms of community acquired pneumonia?

Answer 26

- cough - increased sputum - dyspnoea - chest pain - fever

Question 27

what is seen on chest xray in community acquired pneumonia?

Answer 27

chest xray with infiltrates

Question 28

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

Answer 28

temperature 38.0, left base crackles

Question 29

what is pathology of community acquired pneumonia?

Answer 29

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

Question 30

what is aspiration pneumonia?

Answer 30

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

Question 31

what are some bugs common in pneumonia in immunosuppressed?

Answer 31

- Pneumocystis jiroveci, Aspergillus sp. , endemic mycoses - Mycobacterium tuberculosis , non-tuberculous mycobacteria

Question 32

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

Answer 32

- sputum culture - purulence - viral PCR

Question 33

what are risk factors for community acquired pneumonia?

Answer 33

- increasing age - immunocompromised/suppressed patients - smoking

Question 34

who is more likely to have asymptomatic strep?

Answer 34

- child - also military personal

Question 35

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

Answer 35

capsule = key virulence factor, basis of where vaccination comes from (capsule also anti-phagocytic) other virulence factors = surface adhesins, pneumolysin, sIgA protease

Question 36

what are the different ways streptococcus pneumoniae presents?

Answer 36

- pneumonia is most common presentation - can also present as otitis media, bacteraemia, meningitis

Question 37

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

Answer 37

no

Question 38

how should you start treatment of strep pneumoniae?

Answer 38

first treatment = empiric therapy - you take history of relevant allergies

Question 39

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

Answer 39

amoxicillin - if penicillin allergy doxycycline (tetracycline)

Question 40

what antibiotic is prescribed for severe community acquired pneumonia?

Answer 40

co-amoxiclav + doxycycline - if penicillin allergy IV levofloxacin (quinolone) *if in ICU - add clarithromycin

Question 41

what antibiotic is prescribed for severe hospital acquired pneumonia?

Answer 41

amoxicillin + metronidazole + gentamicin (aminoglycoside) - if penicillin allergy, co-trimoxazole, metronidazole, gentamicin

Question 42

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

Answer 42

amoxicillin + metronidazole - if penicillin allergy = co-trimoxazole + metronidazole

Question 43

what are the 4C antibiotics?

Answer 43

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

Question 44

what is invasive pneumococcal disease?

Answer 44

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

Question 45

when should you add vancomycin?

Answer 45

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

Question 46

how can pneumonia infection cause empyema?

Answer 46

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

Question 47

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

Answer 47

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

Question 48

what tests should be done for legionella pneumonia?

Answer 48

- PCR from sputum - legionella urinary antigen - culture

Question 49

what is treatment of legionella pneumonia?

Answer 49

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

Question 50

is legionella gram negative or gram positive?

Answer 50

gram negative

Question 51

where is legionella?

Answer 51

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

Question 52

how is legionella transmitted?

Answer 52

Transmitted by inhalation of contaminated water droplets

Question 53

what are symptoms of legionella?

Answer 53

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

Question 54

what are typical symptoms of mycoplasma pneumonia?

Answer 54

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

Question 55

what are the main diagnostic tests in legionella?

Answer 55

- culture - urinary antigen test - nucleic acid-based detection from different places - respiratory tract specimens, blood, urine

Question 56

what is treatment of mycoplasma pneumonia?

Answer 56

= has no cell wall →amoxicillin NOT treatment of choice - clarithromycin and if not ciprofloxacin

Question 57

when does staphylococcus aureus pneumonia occur?

Answer 57

post influenza - spreads haematogenous (lymphatic spread)

Question 58

what is the drug of choice for staphylococcus aureus pneumonia?

Answer 58

co-trimoxazole then doxycycline

Question 59

what is whooping cough (pertussis)?

Answer 59

- 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

Question 60

what is bacteria causing whooping cough?

Answer 60

bordetella pertussis = gram negative coccolbacillus

Question 61

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

Answer 61

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

Question 62

does every COPD examination need antibiotics?

Answer 62

no

Question 63

can resistance spread?

Answer 63

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

Question 64

what are some viruses which cause pneumonias?

Answer 64

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

Question 65

what are examples of evasion?

Answer 65

- 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

Question 66

who are more vulnerable to aspergillus?

Answer 66

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

Question 67

what is aspergillus?

Answer 67

fungus that can cause pneumonia

Question 68

what cells are involved in bacterial infection?

Answer 68

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

Question 69

what cells are involved in virus infections?

Answer 69

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

Question 70

what cells are involved in fungal infections?

Answer 70

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