Gram Negative Diplococci
Neisseria spp.
Moraxella spp.
Grows on Chocolate + Blood agar 5-10% CO2, 37C
Neisseria, Moraxella, Haemophilus
Moraxella spp colony morphology
1-3mm, grey, round, smooth, dry, no haem
PUSHABLE!
Moraxella spp basic characteristics
Gram negative diplococci (coffee bean - coccobacilli in pairs)
KOH positive
Oxidase positive!
Catalase positive
Oxidase Positive bacteria
Neisseria, Moraxella, Haemophilus, Pseudomonas
Moraxella gram stain
Gram Negative diplococci
Can resist decolourisation. (appears purple).
Is Moraxella spp fastidious?
No
Presumptive moraxella tests?
- Taxo sugar utilization tests
- DNase Test
- Catarrhalis Disk test
DNase test procedure
- Divide DNA agar plate into 3
- Spot inoculate test on 1 half (10mm) and controls (pos = M.Catarrhalis, neg = N. Lactamica ) on other half.
- Incubate at 37C overnight.
- Following incubation, in fume hood flood plate with 1M HCl and allow acid to permeate for 10 mins and carefully pour off excess into discard jar.
Pos = distinct clear zones around inoculum = M, catarrhalis
Neg = N lactamica.
Catarrhalis disk test procedure
- Use forceps to remove catarrhalis disc from vial and place on plastic lid of sterile petri dish.
- Rub several colonies (visible inoculum) across disk using wooden applicator.
- Wait for 2 mins for colour change.
Pos control = M.catarrhalis
Neg control = N lactamica.
Pos= blue-green colour change.
Moraxella spp. DNase test result
Positive =M
Moraxella taxo sugar utilization test results
Negative for all sugars.
Moraxella infections
URT = otitis media, sinusitis, laryngitis
LRT = bronchitis, pneumonia
Moraxella specimens
Ear swab, sputum
Moraxella treatment
Amoxicillin, clarithromycin
Do AST first.
