Moraxella catarrhalis

Question 1

Type

Answer 1

Diplococci
Gram negative
Aerobic
Oxidase +
Non motile

Question 2

Transmission
& season

Answer 2

Colonizes
URT, in
children
Dependant on
age

Question 3

Presentation

Answer 3

1. COMMON cause of
   Otitis Media in
   children
   - Colonization of
   nasopharynx →
   migrate to middle ear
   through eustachian
   tube → precipitated
   by viral URI
2. Acute exacerbation
   of COPD in elderly
   - Altered mucociliary
   function: enter LRT,
   small aspirations
   happen
   - Airway colonization
   and infection
   - Triggered by
   acquisition o

Question 4

Pathogenesis

Answer 4

1. Adherence to
   respiratory epithelium
2. Intracellular invasion
3. Complement
   resistance
4. Biofilm formation:
   restricted to chronic or
   COPD pts
5. Induction of
   inflammation
6. As a co-pathogen: can
   be isolated with other
   pathogens

Question 5

Diagnostic

Answer 5

Mostly clinical
Lab diagnosis:
- Gram -ve
diplococci (also
Neisseria)
- differentiate by
DNAse+ve and
Nitrate
reduction +ve
- Blood and
chocolate Agarround, opaque
colonies
- Hockey puck
sign
- Colonies turn
pink in 48 hrs

Question 6

Prognosis &
Prevention

Answer 6

Produce B
lactamases,
resistant to
penicillin -
No vaccine