Ear infections Flashcards
(29 cards)
amoxicillin/clavulanate
Penicillin Binding Protein (transpeptidases) that catalyze the terminal reactions in cell wall synthesis.
Inhibit cross-linking of the peptidoglycan by transpeptidase
Occupy D-alanyl-D-alanine substrate site of the transpeptidase
clavulanate = anti-beta-lactamase
ciprofloxacin
bactericidal - inhibit DNA replication by binding bacterial DNA topoisomerase II (gyrase) and IV
Lead to ds breaks → kill cell
Topo II in gram - used in replication, whereas topoIV used with separation of replicated chromosomal DNA into daughter cells (Gram +)
Spectrum: broad spectrum: gram +, gram -, and atypical organisms like mycoplasma (no cell wall)
neomycin
Bactericidal (work in several areas) - prevent formation of initiation complex, cause misreading of mRNA, induces early termination
aminoglycoside = ototoxic
polymixin
Mechanism: Bind to lipopolysaccharide in the membrane creating holes ultimately leading to the release of cellular contents
Spectrum: Multidrug resistant Gram negative bacilli including pseudomonas aeruginosa and K. pneumoniae. Used in combination with other abx to facilitate entry.
hydrocortisone
antiinflammatory
otitis externa
external otic canal
otitis media
middle ear canal
labrinthitis
inner ear
mastoiditis
mastoid bone
acute otitis media
bacterial or viral
otalgia, red ear drum, pus and fever
otitis media with effusion
build up of fluid in e tube, no infection in ear (associated with upper resp infection, cigarette smoke, allergies)
Common agents acute otitis media
Streptococcus pneumoniae: 25-50%
Haemophilus influenzae (mostly non-typable): 15-30%
Moraxella catarrhalis: 3-20%
Viral (especially RSV, rhinovirus): 5-22%
No pathogen identified: 16-25%
strep pneumo culture
gram positive diplococcus
virulence factors strep pneumo
capsule - block phagocytosis
choline-binding proteins - alter vascular permeability
Hydrogen peroxide - damage host cells, bactericidal vs staph aureus
Neuraminidases - cleave host mucins
Pneumolysin - pore forming toxin binds cholesterol, disrupts cilia of cochlea
drug resistant strep pneumo
changes in penicillin binding protein (not beta lactamases)
H. influenzae culture
gram negative pleomorphic coccobacillus
nonmotile biofilms facultative anaerobe
fastidious, require additional blood factors NAD and hematin in chocolate agar
nontypeable (hif)
nonencapsulated colonize nasopharynx –> spread to eustachian tubes = otitis media
hif resistance
b-lactamases
moraxella catarrhalis
gram negative aerobic diplococcus oxidase positive nonmotile fastidious - chocolate agar pili
m. catarrhalis resistance
b-lactamases
tx acute otitis media
6-24 mo - empiric = oral amoxicillin
if no improvement, add clavulanate (anti-beta-lactamase)
otitis externa
unilateral inflammation of ear canal, pain, itching, purulent ear drainage
risk factors OE
maceration - trauma, foreign bodies, excessive moisture, extension of middle ear infection, DM
cerumen contains what
lysozyme and is slightly acidic deterring microbial growth
