Microbiology of RTI Flashcards
causes of classical flu
influenza A
influenza B
causes of flu-like illnesses
parainfluenza viruses
many others
haemophilus influenza is a primary cause of flu. True/ False?
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
flu complications
- primary influenza pneumonia
- secondary bacterial pneumonia
- bronchitis
- otitis media (infection of middle ear)
- perinatal mortality, prematurity, smaller neonatal size and birth weight
flu therapy
- bed rest, fluids, paracetamol
- antivirals: oseltamivir, zanamivir
ways in which the lab can confirm influenza?
- PCR
- immunofluorescence
- antigen detection
- virus culture
- antibody detection (may need paired acute and convalescent bloods so confirmation is often retrospective)
killed vaccine for flu
grown in hen’s eggs/ cell culture, killed, combined with adjuvant
contains 2 influenza A viruses and one influenza B virus
live attenuated vaccine for flu
administered intra-nasally
apart from as a complication of influenza A and influenza B, what are other causes of community acquired pneumonia?
microbiological causes (all bacteria): mycoplasma pneumoniae, coxiella burnetii, chlamydia (These are known as "atypical" pneumonia).
mycoplasma pneumonia
common cause of CAP
children and young adults have highest incidences
person to person spread
coxiella burnetii (Q fever)
causes pneumonia, and pyrexia (Q fever)
uncommon, sporadic zoonosis (sheep and goats)
a complication of it is culture negative endocarditis
chlamydia psittaci
uncommon, sporadic zoonosis (birds)
usually presents as pneumonia
bronchiolitis
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
metapneumovirus
second most common cause (after respiratory syncytial virus) of LRTI in young children.
chlamydia trachomatis
STI which can cause infantile pneumonia, diagnosed by PCR on urine of mother or throat swabs of child
chlamydophila pneumonia
person to person
mostly causes mild respiratory infections
may be picked up by test for psittacosis
the common cold is caused by viral infections. Give examples?
rhinoviruses adenoviruses enteroviruses influenza viruses parainfluenza viruses metapneumoviruses (there is sneezing, nasal blockage which becomes purulent, secondary bacterial infection may result)
what are the first and second most common causes of LRTI in young children?
RSV
metapneumovirus
what are some viral and bacterial causes of acute pharyngitis, and tonsillitis?
viruses: influenza, rhinovirus, adenovirus, enteroviruses, Epstein barr, cytomegalovirus
Bacteria: Strep pyogenes and sometimes other B-haemolytic strep groups
what causes croup (laryngotracheobronchitis)?
mostly viruses - parainfluenza viruses
there is stridor, barking cough, hoarse voice
Typically, who gets pneumonia caused by Staph aureus?
PWIDs, people after having flu
Typically, who gets pneumonia caused by legionella species?
people who have travelled recently, also smokers and immunocompromised are more at risk
who gets pneumonia caused by Chlamydophila psittaci?
people who have contact with birds
who gets pneumonia caused by Coxiella burnetii?
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)
who typically gets pneumocystic pneumonia (caused by the yeast-like fungus pneumocystis jirovecii)?
people who are immunocompromised e.g. those with HIV/ undergoing chemotherapy
who typically gets klebsiella pneumonia pneumonia?
alcoholics (aspiration)
people with weakened immune systems
who typically gets pneumonia caused by pseudomonas aeruginosa?
people with cystic fibrosis
