outermost structural component of gram pos bacteria
peptidoglycan
outermost component of gram neg bacteria
LPS
how does a strain with bacteriophage become toxigenic
transduction
endotoxin is property of
gram neg
exotoxin is property of
gram pos
doubling time of strep pneumo
20-30 mins
doubling time of m. tuberculosis
12-24 hours
which phase of growth are bacteria most susceptible to antibiotics
exponential growth phase
CM: nasal stuffiness, headache, sneezing
common cold (rhinitis)
bug in common cold
rhinovirus
pathophys of common cold
rhinovirus infects cells lining nasal passages and pharynxleads to inflammation: columnar epithelial cells are destroyed and slough off
big source of spread for common cold
fingers
how long can cold viruses survive on skin and hard surfaces
>5 hours
CM: pharyngitis, coryza, CONJUCTIVITIS, FEVER, malaise, headache, abdominal pain
adenovirus
adenovirus most likely to occur in
children, young adults, institutional settings (military, schools, dorms, daycare)
adenovirus causes
pharyngoconjunctival fever
CM: sneezing, rhinorrhea, nasal congestion, post-nasal drip, facial pressure, fevere, sore throat
acute rhinosinusitis
acute rhinosinusitis is
inflammation/infection of mucosa of nasal passages and at least on of the paranasal sinuses
most common cause of acute rhinosinusitis
viruses (rhino, RSV, parainfluenza)
acute bacterial rhinosinusitis most common cause
s. pneumo*haemophilusmoraxella catarrhalis
pathophysiology of rhinosinusitis
obstruction of paranasal ostia impedes drainage of mucus secretions, bacteria grow
diagnosis of acute rhinosinusitis
symptoms worsen after 5 days and persist beyond 10 daysworsening symptoms after initial improvement
CM: ear pain, ear pressure, middle ear effusion
otitis media
otitis media MCC
s. pneumo*h. influenzamoraxella catarrhalis
otitis externa common in
swimmers
otitis externa MCC
pseudomonas aeruginosa
CM: fever, sore throat, edema, hyperemia of tonsils and pharyngeal walls, painful swallowing
pharyngitis
most common cause of pharyngitis
virus: coxsackievirus, rhinovirus
MCC bacterial cause pharyngitis
strep pyogenes (GAS)
pharyngitis can lead to
glomerulonephritis and rheumatic fever
strep pyogenes contains
M protein
GAS is
beta-hemolytic
strep pyogenes is catalase
negative
CM: "BULL-NECK APPEARANCE" due to regional lymphadenopathy, pharyngeal pain, cough, UNVACCINATED CHILDREN
diphtheria
pathophys of diphtheria
PSEUDOMEMBRANE coats throat and can obstruct airways
diphtheria bug
corynebacterium diphtheriae
CM1. URI symptoms2. paryoxysmal cough, sometimes followed by vomiting3. paroxysms decrease in frequency and intensityUNVACCINATED CHILDREN
bordatella pertussis (whooping cough)
clinical finding in whooping cough
high WBC with lymphocytes in children
whooping cough in adults
chronic cough for 7 days
epiglottitis is a medical emergency caused by
H. influenzae in unvaccinated childrengroup a strep in adults
pathophys of epiglottitis
Hib colonizes pharynx and enters epiglottis via breaks in mucosal surface"thumb sign" on x-ray
four D's of epiglottitis
dysphagiadysphoniadroolingdistress
onset of epiglottitis
rapid
CM: begins with prodromal mild URI with coryza, sore throat, cough for 2-3 dayshoarseness, BARKING COUGH, stridor, sternal retraction, dysphonia, mild fevere, STEEPLE SIGN in AP neck radiograph
croup syndrome
who usually gets croup syndrome
6 months to 3 years
MCC croup syndrome
parainfluenza virus* (ssRNA-)RSV, influenza
croup syndrome path
viral infection of upper respiratory tract causes inflammation and edema of larynxlaryngitis, viral infection in larynx, trachea, and bronchi in viral croup
CM: low grade fever follows prodromal URI, diffuse expiratory WHEEZE with crackles, hypoxia, HYPERINFLATION seen on x-ray
RSV
rapid detection of RSV via
serological testing
virus in RSV
paramyxovirus
RSV has outbreaks when?
winter months
CM: abrupt onset of fever, chills, non-productive cough, muscle aches
influenza
virus of influenza
orthomyxovirus, enveloped
genome of orthomyxovirus
8 ssRNA segments surrounded by helical capsids
influenza virus surrounded by two glycoprotein spikes:
hemagglutinin and neuraminidase
be wary of what with inlfuenza
post-flu pneumonia
hemagglutinin
binding of virus to host cell via sialic acids on host cell surface, trigger endocytosis
neuraminidase
hydrolyze sialic acid to release mature virion after budding
antigen drift
slow gradual change in viral antigens
antigen shift
2 RNA segments re-assort into a new virus
what causes massive outbreaks in influenza
antigenic shift
MCC of typical pneumonia
strep pneumoniae
MCC interstitial pneumonia
mycoplasma pneumoniae
strep pneumo important virulence factor
polysaccharide capsule, antigenic and antphagocytic
strep pneumo has
IgA protease: essential for surviving descent into lungs
other causes of typical pneumonia
staph aureushaemophilus influenzaeklebsiella pneumoniae
staph aureus is catalase
positive
staph aureus is coagulase
positive
klebsiella common cause of
aspiration pneumoniaALCOHOLICS, hospitalized patients
staph common cuase of
acute lobar pneumonia and POST-INFLUENZA PNEUMONIA
CM: mild cough, DIARRHEA, ABDOMINAL PAIN, pneumonia with headache, HIGH FEVER, chills, dry cough, chest pain
leigonella pneumophila
risk factors for legionnaires
significant smoking historyadvanced age
legionella acquired from
environmental water sources
how is legionella detected
urine antigen test
CM: gradual onset of headache, fever, chills, malaisefollowed by dry coughearache
atypical pneumonia
atypical pneumonia also caused by
chlamydia pneumoniae
cytoplasmic membranes of mycoplasma pneumonia consist of
sterols
component of membranes mycoplasma pneumoniae
cold agglutinins
cystic fibrosis bacteria in lungs
pseudomonas aeuruginosa
path of pseudomonas
exotoxin a inhibits eukaryotic elongation factor preventing protein synthesis leading to cell death