Microbiology of RTI

Question 1

causes of classical flu

Answer 1

influenza A

influenza B

Question 2

causes of flu-like illnesses

Answer 2

parainfluenza viruses

many others

Question 3

haemophilus influenza is a primary cause of flu. True/ False?

Answer 3

False.
It may be a secondary invader. It’s Gm-ve, coccobacillary, facultatively anaerobic pathogenic bacterium.
Causes initial symptoms of an URTI (mimicking a viral infection). May progress to LRTI

Question 4

flu complications

Answer 4

• primary influenza pneumonia
• secondary bacterial pneumonia
• bronchitis
• otitis media (infection of middle ear)
• perinatal mortality, prematurity, smaller neonatal size and birth weight

Question 5

flu therapy

Answer 5

• bed rest, fluids, paracetamol

- antivirals: oseltamivir, zanamivir

Question 6

ways in which the lab can confirm influenza?

Answer 6

• PCR
• immunofluorescence
• antigen detection
• virus culture
• antibody detection (may need paired acute and convalescent bloods so confirmation is often retrospective)

Question 7

killed vaccine for flu

Answer 7

grown in hen’s eggs/ cell culture, killed, combined with adjuvant
contains 2 influenza A viruses and one influenza B virus

Question 8

live attenuated vaccine for flu

Answer 8

administered intra-nasally

Question 9

apart from as a complication of influenza A and influenza B, what are other causes of community acquired pneumonia?

Answer 9

microbiological causes (all bacteria): mycoplasma pneumoniae, coxiella burnetii, chlamydia
(These are known as "atypical" pneumonia).

Question 10

mycoplasma pneumonia

Answer 10

common cause of CAP
children and young adults have highest incidences
person to person spread

Question 11

coxiella burnetii (Q fever)

Answer 11

causes pneumonia, and pyrexia (Q fever)
uncommon, sporadic zoonosis (sheep and goats)
a complication of it is culture negative endocarditis

Question 12

chlamydia psittaci

Answer 12

uncommon, sporadic zoonosis (birds)

usually presents as pneumonia

Question 13

bronchiolitis

Answer 13

inflammation of the bronchioles (caused by viruses)
usually occurs in children under 2
no vaccine
mainly caused by RSV
nosocomial spread in hospital wards
passive immunisation has poor efficacy

Question 14

metapneumovirus

Answer 14

second most common cause (after respiratory syncytial virus) of LRTI in young children.

Question 15

chlamydia trachomatis

Answer 15

STI which can cause infantile pneumonia, diagnosed by PCR on urine of mother or throat swabs of child

Question 16

chlamydophila pneumonia

Answer 16

person to person
mostly causes mild respiratory infections
may be picked up by test for psittacosis

Question 17

the common cold is caused by viral infections. Give examples?

Answer 17

rhinoviruses
adenoviruses
enteroviruses
influenza viruses
parainfluenza viruses
metapneumoviruses
(there is sneezing, nasal blockage which becomes purulent, secondary bacterial infection may result)

Question 18

what are the first and second most common causes of LRTI in young children?

Answer 18

RSV

metapneumovirus

Question 19

what are some viral and bacterial causes of acute pharyngitis, and tonsillitis?

Answer 19

viruses: influenza, rhinovirus, adenovirus, enteroviruses, Epstein barr, cytomegalovirus
Bacteria: Strep pyogenes and sometimes other B-haemolytic strep groups

Question 20

what causes croup (laryngotracheobronchitis)?

Answer 20

mostly viruses - parainfluenza viruses

there is stridor, barking cough, hoarse voice

Question 21

Typically, who gets pneumonia caused by Staph aureus?

Answer 21

PWIDs, people after having flu

Question 22

Typically, who gets pneumonia caused by legionella species?

Answer 22

people who have travelled recently, also smokers and immunocompromised are more at risk

Question 23

who gets pneumonia caused by Chlamydophila psittaci?

Answer 23

people who have contact with birds

Question 24

who gets pneumonia caused by Coxiella burnetii?

Answer 24

farm workers and vets (diagnosis is by serology as this organism won’t grow on culture - which is just as well as the illness is contracted by inhalation)

Question 25

who typically gets pneumocystic pneumonia (caused by the yeast-like fungus pneumocystis jirovecii)?

Answer 25

people who are immunocompromised e.g. those with HIV/ undergoing chemotherapy

Question 26

who typically gets klebsiella pneumonia pneumonia?

Answer 26

alcoholics (aspiration)

people with weakened immune systems

Question 27

who typically gets pneumonia caused by pseudomonas aeruginosa?

Answer 27

people with cystic fibrosis