Microbiology of Upper Respiratory Infections Flashcards Preview

Respiratory 2 > Microbiology of Upper Respiratory Infections > Flashcards

Flashcards in Microbiology of Upper Respiratory Infections Deck (19):
1

Rhinitis

ssRNA+ (naked)

Nasal stuffiness, HA, neeze

RHinovirus infects cells in nasal passage...columnar epithelial cells sloughed off

2ndary bacterial infectiou occurs IF you get blockage of sinus ostia or ET

DOn't spread further down bc too farm

Fingers are best spread...enter through nasal mucosa and eye

Survive a long time on the skin

2

Adenovirus

dsDNA (llinear) naked

Pharyngitis with conjunctivitis and fever

More likely in children, YA or institutional

3

Acute rhinosinusitis

Inflammation of mucos of nasal passages AND at least one of paranasal sinuses

Sneezing, rhinorrhea, nasal congesiton, drip, facial pressure, fever, sort through

Most common - virus

Acute bacterial (preceded by viral) - S. pneumo or Hib

Obstruction of paranasal ostia impedes drainage of mucus secretions ---- bacteria grow

Dx - sx of rhinosinusitis that worsen after 5 days and persist beyond 10 days or worse after initial improvement

4

Mucormycosis

Mucor or rhizopus

Sporanglospores breathed

RHinocerebral infarction starts in nasal caivty...black ulcers

diabetes (DKA), malignancies, immunosuppression

5

Otitis media

Ear pain, pressure, middle ear effusion

More likely in children bc shorter, flexible, horixzonal ETs...effusious in ET become infected with nasopahryngeal contents

Usually preced by viral URI that causes swelling of lining of inner ear

S. pneumo, Hib

6

Otitis externa

Swimmers ear

Excesvie moisture in ear canal raises pH and removes cerumen

Psuedomonas

7

Pharyngitis

Fever, sore throat, edema, hyperemia of tonsils and pharyngela walls with painful swalling

Viral - virsues gain access to mucosal lining nasopharynx and replicate, causing damage (cox, rhino)

Bacterial - normal Strep pyo...attaches to mucosal cells via M protein

8

Strep pyo structure

Hyaluronic acid capsule (non immunogenic)

M-protein required for virulence...extend from anchor in cell membrane

9

How to diff Aureus and pyogenes

Hemolytics

Catalase pos - aureus

Beta - S. pyo...clear
Alpha - green (partial)...S.pneumo

10

Diptheria

Corynebacterium diptheriae

Worldwide dist

Chinese lettering

Bullneck appearance due to LAD, pahryngeal pain, cough

Lysogenic phage encoade A+B toxin (irojn regulated)

Thick adherett psedomembrane that is composed of cell debris...coats throgh and can obstruct airway

Grow on cycteine-tellurite agar

11

A+B toxin entry

Binding, recpetor mediated endocytosis, acidification and release of A subunit across membrane

12

Exotoxin A

Diptheria and Pesudomonas

Uses ADP ribosylation ot inhibit protein syntehsi

13

Epiglottitis

Hib (kids)
Group A strep (adults )

Hib colonizes pharynx and enrters epiglottis via brekas in mucosa...thumb sign on XDysphagia, dysphonia, drooling, distresss

RAPID ONSET

HIB needs chocolate agar to grow

14

Hib virulence factors

Pilli

Capsule that inhibits phagocytosis

Capsular PS antigens

Grows on chocolate agar (fastidious)

15

Whooping cough

Bordetella pertussis

Infection of large bronchi

1-2 weeks of URI
2-4 weeks of paroxysmal cough followed by whoot or vomiting
Up to 6 months to get ridd of
Grow non B-G or R-L agar

High WBC count with lymphocytosis in children

A-B toxin that activates adenylate cyclase through GPCR

16

Medically relevant ssRNA - viruses

All enveloped

17

Croup

Parainfluenza (ssRNA neg)

6 mos to 3 years (Fall-winter)

Prodromal mild URIwith cough for 2-3 days

Darking cough, sridor, dysphonia, steeple sign

18

Influenza

Orthmyxovirus, enveloped

Eight ssRNA neg segments with helical cpasids

ABRUPT onset

HA - binding of virus to host cell via sialic acids on host cell surface (trigger endo)(

NA - hydrolyze sialic acid to release mature after budding

19

Antigenic drift and shift

Drift - slow gradual changes in viral antigens

Antigenic shift - re-assort viral genome to rpduce H5N1 from H1N1 and H5N2