4-Upper Respir Tract Bacteria

Question 1

upper respiratory tract has

Answer 1

conjuctiva + nasolacrimal ducts + middle ear + eustachian tube + nares + nasal cavity + pharynx + sinuses + larynx + epiglottis

Question 2

URT defenses

Answer 2

1. ciliated epi in conductive airway
2. mucocillary escalator- impaired by viral infection, smoke, alc, narcotics

Question 3

normal microbiota in nasal cavity

Answer 3

1. staph epidermidis
2. staph aureus (MRSA esp healthcare workers)
3. corynebactterium spp

Question 4

nasopharynx microbiota

Answer 4

1. Strep pneumoniae
2. moraxella catarrhalis
3. notypeable haemophilius influenze

main ones causing dz, all are opportunistic

Question 5

pharyngitis

Answer 5

inflam of pharynx
-usually viral but can be strep pyogenes or cornyne (less common)

Question 6

streptococci classifications

Answer 6

gram + cocci in chains + catalase neg

1. lancefield serogrouping (A-H)- cell wall carb antigens
2. hemolysis- alpha, beta, gamma
3. biochem properties

Question 7

strep pyogenes diseases

Answer 7

aka group A strep (GAS)
1. pharyngitis
2. sequelae (scarlett fever, rheumatic fever, rheumatic heart dz)

Question 8

strep throat clinical presentation

Answer 8

1. swollen tonsils and uvula (anterior cervical lymphadenopathy)
2. edema and erythema of pharyngeal
3. pus (tonsillar exudate)
4. pain/diff swallowing
5. fever

spreads by sneezing and coughing, food contaminated by respir droplets

will spont resolve in a week

pharyngitis from S. pyogenes

Question 9

pyogenes virulence factors

Answer 9

1. M protein- degrades complement
2. capsule hyaluronic acid- inhibits phagocytosis
3. strep pyogenic exotoxins- scarlett fever, toxic shock, necrotizing fascilits

Question 10

diagnose pharyngitis

Answer 10

1. absence of viral pharyngitis (no cough or runny nose, diarrhea)
2. anterior cervical lymphadenopathy
3. high temp +100.4
4. tonsillar exudates/swelling

rapid strep test for lancefield group A antigen + follow up culture

Question 11

pharyngitis treatment

Answer 11

usually antibiotic therapy for S. pyogenes
-avoid crowds

Question 12

non suppurtive complications pharyngitis

Answer 12

1. scarlett fever
2. acute rheumatic fever
3. strep toxic shock
4. poststrep glomerulonephritis
5. PANDAS (peds autoimmune neuropsychiatric)

from S. pyogenes

Question 13

scarlet fever - pyogenes

Answer 13

mostly in kids after GAS pharyngitis
-sandpaper rash + strawberry tongue
-no systemic spread only in throat bc exotoxins produced at site of infection

treat antibiotics

Question 14

acute rheumatic fever

pyogenes

Answer 14

two types
1. acute febrile illness- weeks after GAS infections
-arthritis in large joints, carditis/valvulitis, fever
2. neurologic illness-months after GAS infection
-sydenham chorea, no fever or joint symps

Question 15

acute rheumatic fever treatment

Answer 15

1. antibiotics for GAS or recurrent active infection
2. anti-inflammatory for arthritis
3. manage heart dz/failure

Question 16

acute rheumatic fever mechanism

Answer 16

antibodies and T cells activated vs GAS during infection then cross react with host proteins = autoimmune mediated damage
-molecular mimicry

GAS infection absent in new acute rheumatic fever cases

Question 17

diptheria pharyngitis

Answer 17

unique type of pharyngitis from cornye diphtheriae
-toxin mediated

low grade fever + mild sore throat + bull neck (super swollen lymph nodes) + pseudomembrane formation on oro/naso/laryngopharynx
-if untreated lead to kidney fail, myocarditis, death
-pseudomembrane pieces can cause suffocation

Question 18

diptheria exotoxin

Answer 18

AB exotoxin carried on lysogenic bacteriophage
-stops protein syn via ADP ribosylation of elongation factor 2

local and systemic manifestations

Question 19

how diptheria spreads

Answer 19

aerosol
respir droplet contamin of fomites
-rare in US

Question 20

treating diptheria

Answer 20

IV diph antitoxin
-airway management to prevent suffocation
-antibiotics

prevent with DTaP vaccine

Question 21

epiglottitis

Answer 21

inflamm swelling of epiglottis
1. acute = haemophilus influenzae serotype B > airway obstruction, high fever, stridor, drooling, muffled voice, severe sore throat, toxic facies
2. subacute = sore throat, diff swallowing, low grade fever, GAS (pyogenes, aureus, pneumoniae)

Question 22

haemophilus influenzae strains

Answer 22

1. typeable strain has capsule (polysac of PRP) types A-F
   -B is most dangerous (HiB)
2. nontypebale no capsule (NTHi)

Question 23

HiB virulence factors

Answer 23

IgA protease
PRP capsule makes antiphagocytic

mostly pediatric esp if unvaccination/improperly vac

spread by drolpets

Question 24

HiB treatment

Answer 24

dx by culture and gram stain (looks like chocolate/brown)

-antibiotic therapy but if untreated then death
-prevent by conjugate vaccine but not protect against typeable

Question 25

otitis externa

Answer 25

infection and inflamm with auditory canal -swimmers ear **pseudo aeruginosa, staph aureus** -fungi can also cause (candida albicans, asperigillus) antibiotic ear drops to treat

Question 26

acute otitis media

Answer 26

inflamm of middle ear -childhood dz huge economic burden and #1 cause of office visits, antibiotics, hearing loss, and surgery with anesthesia for kids

Question 27

why kids more sensitive acute otitis media

Answer 27

eustachian tube is short, floppier, more horizontal

Question 28

acute otitis media bacterias

Answer 28

1. strep pneumoniae- normal microbiota, 'the pneumococcus' 2. NTHi 3. moraxella catarrhalis

Question 29

acute otitis media presentation

Answer 29

1. unexplained crying 2. pulling at ears 3. otorrhea- pus out ear canal 4. GI 5. concurrent/preceding viral URTI

Question 30

acute otitis media risk factors

Answer 30

-second hand smoke -daycare attendance -seasonality (winter)

Question 31

treatment acute otitis media

Answer 31

1. antibiotics (amoxicillin) 2. watchful waiting if non severe, older than 2 3. severe recurrent cases need antibiotics and tympanostomy prevent by vac for pneumococcal AOM somewhat effective (pneumococcal polysac 23 valent or 13 valent conjugated to diphetheria toxoid)

Question 32

sinusitis/rhinosiusitis

Answer 32

inflamm of paranasal sinuses or nasal cavity strep pneumoniae NTHi moraxella catarrhalis | same as otitis media

Question 33

sinusitis dx

Answer 33

bacteriology etiology if 10+ days, severe symptoms after 3 days, following an improving viral URT treat with waiting or antibiotics in severe/worsening

Question 34

conjunctivitis

Answer 34

pink eye aka inflamm of conjunctiva bacterial = purulent discharge -also viral, allergic, non allergic etiologies

Question 35

acute conjunctivitis

Answer 35

1. common bacterial- eye or nasal secretion from infected **aureus, pneumoniae, NTHi, moraxella** 2. hyperacute- genitals to eyes **neisseria gonorrhoeae**

Question 36

chronic conjunctivitis

Answer 36

1. adult inclusion- genitals to eyes, STI strains, 2. trachoma- eye or nasal secretions, non STI stains both from **chlamydia trachomatis**

Question 37

neonatal conjunctivitis

Answer 37

1. neonatal inclusion- birth canal, STI strains, mucopurulent discharge **C. trachomatis** 2. gonococcal conjunctivitis- birth canal **N. gonorrhoeae**

Question 38

chlamydia characteristics

Answer 38

medially relevant species 1. chlamydia trachomatis 2. chlamydia psittaci 3. chlamydia pneumoniae very small obligate intracellular bacteria

Question 39

chlamydia life stages

Answer 39

1. elementary bodies- metabolic inactive, infectious 2. reticulate bodies- metabolic active, noninfectious

Question 40

chlamydia trachomatis pathogenesis

Answer 40

direct destruction of host cells during rep = collateral damage from host infalmm resp

Question 41

treating conjunctivitis

Answer 41

adult and neonatal inclusion forms -antibiotics via ophthalmic drops, ointment, oral