L13- RTI IV Flashcards
Moraxella Cattarhalis:
- Gram(+/-)
- (2) shape
- (aerobic/anaerobic/both)
- oxidase(+/-)
- (non-/motile)
Gram- diplococcus, aerobe, oxidase+, non-motile
what are the common Gram- diplococci
- moraxella cattarhalis
- Neisseria spp.
Moraxella Cattarhalis:
- (1) antibiotic resistance
- (2) colonization factors and location
1- produces β-lactamases –> penicillin resistant
2:
- biofilm formation to colonize URT in children
- colonization is dependent on age and co-morbidities
Moraxella Cattarhalis:
- (1) and (2) are its most prevalent diseases
- (3) are other diseases caused by it
1- otitis media, common cause in children
2- COPD acute axacerbations in elderly
3- sinusitis, pneumonia, bacteremia, periorbital cellulits, conjunctivitis
what will commonly induce COPD exacerbations in the elderly
- Moraxella Cattarhalis
- common cold viruses: rhinovirus, adenovirus, coronavirus
describe pathogenesis of Moraxella Cattarhalis in otitis media
1) colonization of nasopharynx
2) migration from nasopharynx to middle eat via Eustachian tube —- usually precipitated by viral URI
describe pathogenesis of Moraxella Cattarhalis in exacerbation of COPD
1) altered mucociliary function
2) airway colonization and infection
3) triggered by acquisition of new strains –> they dirupt protease - antiprotease balance
Moraxella Cattarhalis: list some of the molecular mechanisms / virulence factors (hint- 6)
- many adhesins for attachment to respiratory epithelium
- intracellular invasion
- complement resistance
- biofilm formation
- induction of inflammation
- acts as a co-pathogen
Moraxella Cattarhalis:
- diagnosis is typically done by (1)
- (2) is suggested, explain process and results
1- clinically, treat empirically
2:
i) Gram stain => Gram- diplococcus –> now must differentiate from Neisseria
ii) chocolate agar: round, opaque colonies with ‘hocky puck’ sign + pink after 48hrs
iii) differentiate from Nesseria: DNase+, Nitrate Reduction+, doesn’t ferment carbohydrates
list the 3 diagnostic differences between Moraxella Cattarhalis and Neisseria spp.
Moraxella Cattarhalis:
1) hockey puck sign (slides like it on agar when touched)
2) DNase+, Nitrate Reduction+
3) doesn’t ferment carbohydrates
Epidemic flu is transmitted from (1) animals via (2) that can survive in the environment for (3). Epidemic flu will last about (4) in a community, where most affected people will be (5).
1- man-to-man
2- respiratory droplets / aerosols
3- ~24hrs (survives drying, depends on humidity)
4- 4-6 wks maximum (rarely lasts longer)
5- recover spontaneous with long-lasting, but weak immunity to particular strain
Flu Symptoms in adults:
- (1) incubation period
- sudden appearance of (2) lasting a few hrs
- (3) symptoms lasting 3-8 days (indicate an important absent symptom)
- (4) recovery days
- (5) contagious days
- (6) highest risk for secondary infections days
1- 1-4 days
2- malaise, HA
3- abrupt rise of fever, chills, severe muscle aches + loss of appetite, non-productive cough (*NO rhinorrhea usually)
4- 7-10 days
5- after 24 hrs for next 7 days
6- 6-12 days post infection
what are the additional symptoms of flu seen in children
- higher fever
- GI Sxs: vomiting, abdominal pain
- earache / otitis media
- muscle pain, sometimes with swelling
- croup often, not always
- febrile convulsions: children under 3, rare occurrence
Influenza virus:
- (1) family
- (non-/enveloped) (linear, circular, segmented) (+/-) sense (ss/ds)(DNA/RNA)
- (7) site of viral replication
1- orthomyxoviridae
enveloped, segemented (-) sense ssRNA
7- replicates in host cell nucleus
describe the structural differences of the influenza subtypes
(classification based on matrix and nucleoproteins)
A- 8 ssRNA segments, subtypes based on surface glycoproteins: hemagglutinin (H), neuramidase (N)
B- 8 ssRNA segments
C- 7 ssRNA segments