Kozel > 2nd Tier Pathogens Flashcards
what shape is pneumococcus?
lancet/ovoid
is pneumococcus encapsulated?
YES
older cultures of pneumococcus undergo ________ because why?
autolysis
autolytic enzymes are activated by surfactants (bile, detergents)
what conversion happens in pneumococcus?
rough-to-smooth conversion by transformation
what do you grow pneumococcus on?
blood agar
what is the major antigen of pneumococcus?
capsular polysaccharide
how many serological types of capsular polysaccharide does pneumococcus have?
over 90
is the capsular polysaccharide of pneumococcus essential for virulence?
YES
what is the quellung reaction?
incubation of encapsulated bacteria w/ ab makes the capsule refractile
is pneumococcus quellung positive?
YES
what is C polysaccharide?
aka teichoic acid
cell wall carb that reacts w/ acute phase protein (CRP)
what are the 5 pneumococcal infections?
pneumonia sinusitis otitis media meningitis OTHER > peritonitis, endocarditis, arthritis
pneumococcal pneumonia makes up what % of bacterial pneumonia?
80-90%
where is pneumococcal pneumonia in the lung?
usu lobar
what is the most common cause of otitis media in children >3 mo?
pneumococcus
pneumococcus causes meningitis in what age groups?
young & elderly
what 4 things characterize pneumococcal disease?
- abrupt onset
- toxicity
- fulminant course
- DIC
what causes disease in pneumococcal infections?
inflammatory response to bacterium & its pdts
what is the trick for pneumococcus to be infectious?
produce an inflammatory response but not be killed by it
what are the 3 virulence factors for strep pneumo?
polysaccharide capsule
pneumolysin
peptidoglycan & lipoteichoic acid
what virulence factor of strep pneumo is essential for virulence?
polysaccharide capsule
what fxn does the polysaccharide capsule serve?
prevents phagocytosis
what does anticapsular ab do?
protects by opsonization
what is pneumolysin?
a porin
similar to streptolysin O
what does pneumolysin do?
contributes to inflammation
multiple effects
where are peptidoglycan & lipoteichoic acid found?
cell wall
what do peptidoglycan & lipoteichoic acid do?
activate the alternative pathway
elicit production of IL-1 & TNF-alpha
inflammatory response
what virulence factor of strep pneumo is largely responsible for the inflammatory response?
peptidoglycan & lipoteichoic acid
is natural resistance to strep pneumo high or low?
VERY HIGH!
what % of people carry pneumococci around in their nasopharynx?
40-70%
what are the 4 natural defensive barriers that people have against pneumococcus?
cough & epiglottal reflex
mucus & cilia
phagocytosis by alveolar macrophages
splenic clearance from blood
what is the most important condition altering resistance to pneumococcus?
sickle cell disease
what are the things that can lead to a depressed epiglottal reflex?
alcohol
morphine
anesthesia
what can lead to depressed action of cilia?
viral infection like influenza
what can happen if a pt has hyposplenia or asplenia?
decreased clearance from blood
what 5 things can alter resistance to pneumococcus?
depressed cilia action depressed epiglottal reflex hypo/asplenia malnutrition SICKLE CELL DISEASE
what are the sx of pneumococcal pneumonia?
sudden onset shaking chill fever sharp pleural pain bloody rusty sputum
where does pneumococcal pneumonia localize?
lower lobes
lobar pneumonia
what is pneumonic crisis?
occurred in pre-abx era
dramatic recovery 5-10 days after initial chill
how do you isolate pneumococcus (like what do you grow it on)?
blood agar
how do you differentiate strep pneumo from strep viridans?
pneumo is…
alpha hemolytic
optochin sensitive
bile soluble
what does interpretation of pneumococcal lab diagnosis depend on?
clinical picture
source of specimen
what serological test can you do for pneumococcus?
test for FREE AG in bodily fluids > pneumococcal C polysaccharide
how does pneumococcus enter a person?
upper respiratory tract
T/F: most pneumococcal infections are endogenous
true
what is the incidence of pneumococcus assoc w/?
predisposing factors
do most adults have the capsular ab for pneumococcus?
NO
you have it for N meningitidis & Hib
what are the 3 things important for prevention & control of pneumococcus?
prevent primary damage
immunize
isolate to prevent transmission to at-risk pts
what is PPSV23?
pneumovax
pnu-imune
purified polysaccharide vaccine
how many serotypes does PPSV23 cover?
23
what % of bacteremic cases does PPSV23 cover?
94%
what is the composition of PPSV23?
purified capsular polysaccharide
what is the action of PPSV23?
induction of opsonic ab
what is the efficacy of PPSV23?
60-80%
how long do PPSV23 titers persist?
at least 5 years
is there a booster effect w/ PPSV23?
no
little to no booster effect
for whom is the T-independent ag effective?
> 2yo pts
who should get PPSV23?
all adults over 65 yo in series w/ PCV13
anyone 6-18yo w/ specific risk factors
what is the composition of PCV13?
polysaccharide protein conjugate
what is prevnar 13?
PCV13
polysaccharide protein conjucate vaccine
how many serotypes does prevnar cover?
13
how many serotypes does pneumovax cover?
23
what % of bacteremic cases does PCV13 cover?
> 80%
what % of acute otitis media among kids <6yo does PCV13 cover?
65%
does PCV13 have T-dependent ag?
yes
who should get PCV13?
all children 2-59mo
65yo+ in series w/ PPSV23
at risk kids 6-18yo
what is the point of PCV13?
reduce carriage
produce herd immunity
what are the 2 drugs of choice for pneumococcus IF SUSCEPTIBLE?
penicillin
ceftriaxone
T/F: there are increasing reports of abx-resistant pneumococcus
TRUE
as high as 35% in some regions
what is the resistance mechanism of pneumococcus?
acquisition of PBP w/ reduced affinity for abx
what are alternative meds for pneumococcus?
vancomycin
macrolides
doxycycline
quinolone
what shape is staph aureus?
cocci in clusters
what is on the surface of staph aureus?
protein A
what is the only catalase positive, coagulase positive bacterium?
staph aureus
what are the virulence factors for staph aureus?
adhesive & antiphagocytic factors, toxins, & enzymes
what is MRSA?
methicillin resistant staph aureus
what is the mutation in MRSA?
altered PBP (PBP2’) encoded by mecA gene
what are the toxin-mediated staph aureus diseases?
food poisoning
TSS
scalded skin syndrome
what are the suppurative infections of staph aureus?
impetigo folliculitis furuncles/boils carbuncles bacteremia endocarditis osteomyelitis septic arthritis pneumonia & empyema brain abscess
what shape is bacillus anthracis?
rod
what does bacillus anthracis form?
spores
what is the capsular polypeptide of bacillus anthracis?
poly-glutamic acid
what is the fxn of poly-glutamic acid?
antiphagocytic
what are the 3 exotoxins of bacillus anthracis?
PA > protective ag
EF > edema factor
LF > lethal factor
what is the treatment for bacillus anthracis?
ciprofloxacin
what does cutaneous anthrax look like?
black eschar formation
what does GI anthrax look like?
ulcers at site of invasion
what does the clinical course of inhalational anthrax look like?
non-specific signs then severe sepsis
which form of anthrax is a biothreat?
inhalational
what color is pseudomonas aeruginosa?
green!
aerugula
what shape is pseudomonas aeruginosa?
rod
T/F: pseudomonas aeruginosa is nosocomial
TRUE
what bacterium is the mucoid polysaccharide capsule assoc w/?
pseudomonas aeruginosa
T/F: pseudomonas aeruginosa is highly abx-resistant
TRUE
requires abx combos!
what 5 diseases does pseudomonas aeruginosa cause?
pulmonary infection burn wound infection UTI otitis externa bacteremia
what does pseudomonas aeruginosa infect to cause UTI?
long-term indwelling catheters
what are the strains of pulmonary infection caused by pseudomonas aeruginosa?
mucoid
how does pseudomonas aeruginosa cause bacteremia?
opportunistic infection (e.g. neutropenia)
what shape is burkholderia?
rod
what 3 species of burkholderia do you need to know?
cepacia
pseudomallei
mallei
what does B. cepacia cause?
pulmonary infection in pts w/ underlying lung disease (CF)
what does B. pseudomallei cause?
melioidosis
where does melioidosis occur?
environmental sites in Thailand & N. Australia
what is melioidosis clinically?
pulmonary infection & sepsis
T/F: melioidosis is a biothreat
true
what does B. mallei cause?
glanders in horses
T/F: B. mallei & B. pseudomallei are both biothreats
true
what shape is acinetobacter baumanii?
coccobacillus
acinetobacter baumanii is a ubiquitous ______ in many environments
saprophyte
T/F: acinetobacter baumanii is nosocomial & abx- resistant
TRUE
is acinetobacter baumanii opportunistic?
yes
what disease does acinetobacter baumanii cause in ICUs?
ventilator-assoc pneumonia
what does acinetobacter baumanii do w/ wounds?
infects them, esp on battlefield or w/ repeated exposure to diff medical environments
what shape is H. influenzae?
coccobacilli
what are the nutritional requirements for H. influenzae?
factor X (hemin) factor V (NAD)
what type of H. influenzae is most important?
type b
is Hib encapsulated?
yep
what is the Hib vaccine?
protein conjugate of type b polysaccharide
what 3 (kind of 4) diseases does Hib cause?
meningitis
epiglottitis
acute & chronic otitis media & sinusitis
who gets Hib meningitis?
unimmunized kids
is epiglottitis life-threatening?
yep
T/F: the strains of h. influenzae that cause sinusitis & otitis media are nontypeable
true
e.g. they are acapsular
what are the 2 most common causes of otitis media & sinusitis?
strep pneumo
h. flu
what does franciscella tularensis require for growth?
cysteine! it’s special & dangerous!
T/F: franciscella tularensis is facultatively intracellular
TRUE
what animal primarily gets franciscella tularensis?
rabbits
what are the insect vectors for franciscella tularensis?
hard ticks & biting flies
what disease does franciscella tularensis cause?
tularemia
what is the most common form of tularemia?
ulceroglandular
what does ulceroglandular tularemia follow?
insect bite or direct inoculation
what causes oculoglandular tularemia?
inoculation of eye (rubbing)
what causes pneumonic tularemia?
inhalation
biothreat!
what is psittacosis?
parrot fever
what causes psittacosis?
chlamydophila psittaci
what are the clinical manifestations of psittacosis?
respiratory infection
spread to reticuloendothelial (RES) cells of liver & spleen
what is the natural reservoir for psittacosis?
birds
what does chlamydophila pneumoniae cause?
respiratory infection > sinusitis, pharyngitis, pneumonia
possibly atherosclerosis
what shape is chlamydophila?
rod or coccoid
