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Flashcards in Microbiology Deck (89):
1

what is the clinical presentation of influenza?

fever: high, abrupt onset
malaise
myalgia
headache
cough (initially dry, painless- becomes productive and painful)
prostration (extreme physical weakness)

2

what are the 2 important types of classical flu?

influenza A
influenza B

3

what is haemophilus influenzae?

a Gram-negative, aerobic, small bacilli

4

how is influenza transmitted?

droplets or direct contact with infected respiratroy secretions

5

what are the 5 major complications of influenza?

1. primary influenza pneumonia
2. secondary bacterial pneumonia
3. bronchitis
4. otitis media
5. pregnancy complications

6

what is otitis media?

infection of the middle ear

7

what type of complications can occur if patient gets influenza during pregenancy?

perinatal mortality
prematurity
smaller neonatal size lower birth weigh

8

what is the treatment of flu?

bed rest
fluids
paracetamol

9

when should antivirals be given in the treatment of flu?

only when patient iss at risk of complications

10

what is an antigenic drift?

minor mutations in the antibody binding sites

11

what is an antigenic shift?

process by which 2 or more different strains of virus combine to form a new subtype having a mixture of the surface antigens

12

what types of influenzae can go through antigenic drift?

influenza A
influenza B

13

what types of influenzae can go through antienic shift?

influenza A only

14

what type of mutations to the influenzae virus cause epidemics?

antigenic drifts
(influeza A or B)

15

what type of mutations to the influenzae virus cause pandemics?

antigenis shift
segmented genome
animal reservoi/mixing vessel
(influenza A only)

16

what is the name of the H1N1 sub type of influenzae A?

swine flu

17

what is the best way for direct detection of the influenza virus?

PCR using nasopharyngeal/throat swabs or other respiratory samples

18

what is an indirect way to detect the influenza virus?

antibody detection

19

what 2 types of vaccines used for the prevention of flu?

killed vaccine
live attenuated vaccine

20

who is the killed influenza vaccine given to?

adult patients at risks of complications
health care workers
children 6 months - 2 years at risk of complications
(annually)

21

who is the live attenuated vaccine given to?

offered to
all children 2-5
all primary school children
(because live attenuated vaccine more effective in children 2-17 than killed vaccine)

22

how is the live attenuated vaccine given?

intra-nasally

23

what bacteria are known as 'atypical pneumonia'?

mycoplasma pneumoniae
coxiella burnetti
chlamydophila psittaci/pneumoniae

24

what antibiotics do atypical pneumonia respond to?

tetracycline and macrolides

25

what are the 2 main ways to get lab confirmation ofmycoplasma, coxiella and chlamydophila?

serology
virus detection (PCR on resp swabs/secretions)

26

what 2 disesaes does Coxiella burnetii cause?

pneumonia
pyrexia of unknown origin (Q fever)

27

Coxiella burnetii is a zoonotic bacteria, what does this mean?

an animal infection orginally
(sheep and goats)

28

what is a major complication of Coxiella burnetii?

culture negative endocarditis

29

Chlamydophila psittaci is a zoonotic bacteria, what animal is it caught from?

pet birds
(parrots, budgies, cockatiels)

30

what does Chlamydophila psittaci cause?

Psittacosis

31

what does psittacosis usually present as?

pneumonia

32

how does bronchiolitis usually present?

1st/2nd year of life
fever
coryza
cough wheeze
severe:
(grunting
decreased PaO2
intercostal/sternal indrawing)

33

what are the 2 major severe cimplications of bronchiolitis?

respiratroy failure
cardiac failure

34

what are >90% of bronchiolitis cases caused by?

respiratroy syncytial virus

35

how is RSV confirmed?

PCR on throat/pernasal swab

36

what is the treatment for RSV?

supportive therapy

37

what is the one treatment for RSV which was made but was shown not to reduce mortality and so is not widely used?

monoclonal antibody
(passive immunisation)

38

what is the second most common cause for bronchiolitis?

metapneumovirus

39

how is metapneumovirus confirmed?

PCR on throat/nasopharyngeal swab

40

what is chlamydia trachomatis?

an STI which can cause infantile pneumonia

41

how is chlamydia trachomatis diagnosed?

PCR on urine of mother or pernasal/throat swabs of child

42

how is chlamydophila pneumoniae spread?

person to person

43

what does chlamydophila pneumoniae cause?

mild respiratory infection

44

what are 4 important infections of the trachea and bronchi?

acute epiglottitis
acute exacerbations of COPD
cystic fibrosis
pertussis (whooping cough)

45

what causes acute epiglottitis in children aged 2-7 years old?

haemophilus influenzae

46

why can't you do a normal mouth inspection if you suspect epiglottitis?

because if you push the tongue down the epiglottis will move to the top to cover the airways. if the epiglottis is inflamed it might stick to the top and not come down causing respiratory obstruction

47

what is a test that identifies H. influenzae?

'X and V' test
(H. influenzae needs both factors X and V to grow)

48

where is the habitat of Haemophilus influenzae as part of the normal flora?

upper respiratory tract

49

why do you culture Haemophilus influenzae on chocolate agar instead of blood agar?

chocolate agar makes nutrients more readily accessible

50

what is the treatment for acute epiglottitis?

ITU and ceftriaxone (a 3rd generation cephlasporin)

51

why is acute epiglottits relatively rare now?

most children get a HIB vaccination

52

what are the clinical signs of an infective exacerbation of COPD?

sputum gets worse and changes from clear to green (purulent)

53

what are the 3 most common bacterial organisms associated with an acute exacerbation of COPD?

haemophilus influenzae
streptococcus pneumoniae
moraxella catarrhalis
(all present in normal upper respiratory tract flora, but in COPD colonise lower airways- pathological)

54

when do you give antibioitcs for an acute exacerbation of COPD?

if sputum is purulent
or signs of consolidation on CXR
or signs of pneumonia

55

what is the 1st line treatment of an infective exacerbation of COPD?

amoxicillin 500mg
3x per day (5 days)

56

what is the 2nd line treatment of an infective exacerbation of COPD?

doxycycline 200mg (day 1)
100mg (day 2-5)

57

what is Cystic Fibrosis?

an inherited defect which leads to abnormally viscid mucus which blocks tubular structures in many different organs including lungs)

58

in young CF patients what is the most likely bacteria to be causing infection?

staph aureus
haemophilus influenzae

59

in older CF patients, what are the extermely resistant organisms that can cause infection?

pseudomonas aeruginosa
burkholderia cepacia

60

what oral antibiotic covers pseudomonas aeruginosa?

ciprofloxacin

61

what IV antibiotics cover pseudomonas aeruginosa?

gentamycin
tayzocin

62

what is the organism that causes whooping cough?

bordetella pertussis

63

how would you describe the timing of coughing in whooping cugh?

paroxysmal coughing
(repeated violent exhalations with sever inspiratory whoop)

64

what treatment do you use for borderella pertussis? (whooping cough)

erythromycin

65

what is the clinical features of a patient with CAP?

cough
sputum production
dyspnoea
fever

66

what is the most common cause of CAP?

Strep pneumoniae

67

What are the main causes of CAP?

strep pneumonia
atypicals/viruses
staph aureus
haemophilus influenzae

68

when does staph aureus usually cause CAP?

as a secondary bacterial pneumonia after the flu

69

describe Strep pneumoniae?

gram positive cocci in pairs/short chains, alpha haemolytic

70

why are atypicals not sensitive to penicillins?

because they have a strange cell wall (penicillin usually inhibits cell wall)

71

if the pnemonia is mild what is the likely causative organism?

strep pneumoniae

72

if the CAP is mild (CURB65 0 or 1) what is the treatment? (if oral route available)

amoxicillin 1g TDS PO (5 days)

penicillin allergic:
doxycycline 200mg PO (day 1), 100mg (day 2-5)

73

if the CAP is mild (CURB65 0 or 1) what is the treatment? (oral route unavailable)

amoxicillin 1g TDS IV (5 days)

penicillin allergic:
clarithromycin 500mg BD IV (5 days)

74

if the CAP is moderate (CURB65 2) what is the treatment?

amoxicillin 1g TDS IV/oral (5 days)

penicillin allergic:
doxycycline 200mg PO (day 1), 100mg PO (day2-4)

if penicillin allergic and IV required:
clarithromycin 500mg BD IV (5 days)

75

if the CAP is severe (CURB65 3+) what is the treatment?

Co-amoxiclav 1.2g TDS IV (7 days)
PLUS
clarithromycin 500mg BD IV (7 days)
or
doxycycline 100mg BD PO (7 days)

if penicillin allergic:
Levofloxacin 500mg BD IV (7 days, monotherapy)

76

what are 5 predisposing factors to hospital acquired pneumonia?

intubation
ICU
antibiotics
surgery
immunsuppression

77

what are the clinical features of legionella pneumophila?

flu-like illness which may progress to severe pneumonia
mental confusion
acute renal failure
GI symptoms

78

what is legionella pneumophila associated with?

travel
water

79

how do you diagnose legionella?

legionella urinary antigen
serology
PCR test on sputum

80

what is the tereatment for legionella?

erythromycin/clarithromycin
fluroroquinolones eg levofloxacin
(legionella is a atypical so penicillin cant be used)

81

what type of pneumonia do patients with AIDS get?

pneumocystis jiroveci
(PCP)

82

how do you diagnose pneumocystis jiroveci?

bronchioalvelar lavage (BAL)
induced sputum
direct immunofluorescence (antigen detection)

83

what is the treatment for pneumocystis jiroveci?

co-trimoxazole

84

how long does it take for mycobacterium tuberculosis to be grown on culture?

up to 3 months

85

how do you test for mycobacteria?

positive test to acid and alcohol fast bacili
TB PCR

86

what is the con about acid and alcohol dast bacili testing?

doesnt give an indication of species or antibiotic sensitivity

87

what is good about PCR for TB?

provides information on species and sensitivity

88

what are the pros and cons about culturing TB?

provides best information on antibiotic sensitivity
but very slow

89

when taking a sputum culture why do you want as little saliva as possible?

saliva will have normal flora, you want to isolate causal pathogen as much as possible