Therapeutics - General Principles PT1 Flashcards
name the 3 types of antimicrobial therapy
-prophylactic
-empiric
-definitive
name2 particular populations that get prophylactic antimicrobial therapy
high riskk patients, like HIV patients with CD4 count less than 200, OR for surgical prophylaxis
when giving prophylactic antibiotics to surgical patients, around how long before surgery do they take it
around 1 hour prior because that’s when the concentration of AB will be highest at incision time
explain what empiric therapy is
there’s a suspected or proven infection, but the specific pathogen hasn’t been identified yet
we give broad spectrum as a best guess to what we think the potential pathogens are -want to cover all potential pathogens it may be
when is definitive therapy given
AFTER the culture and susceptibilities results come back – we give a more targeted antibiotic for that specific pathogen identified (based on its suceptibility)
what are the 3 things in the “triangle” approach to antimicrobial therapy
patient, drug, bug
confirming the infection is which of the 3 things in the “triangle” approach to antimicrobial therapy
patient
normal range of WBC count
4-10,000 cells/mm cubed
BUT can vary based on age, gender, comorbidities and also based on different labs where it’s done
what is normal body temp (oral)
what about rectal and axillary
98-98.6
rectal – 1 degree fahrenheit over
axillary - 1 degree farhenheit lower
what temp does the CDC define a fever as
100.4 degrees farhenheit (38 celsius)
is a fever a specific or nonspecific marker
NONSPECIFIC
just because someone has a fever doesn’t mean they have an infection
could be related to an autoimmune disease, malignancy, drug-induced….etc
therefore, diagnosing an infection is a diagnosis of exclusion - must rule out EVERYTHING ELSE FIRST
WBC’s are also known as ________
leukocytes
leukocytosis
term for elevated WBC’s
is leukocytosis specific for infection or nonspecific
NONSPECIFIC - may be due to many other things like stress, malignancy, corticosteroid side effect, etc
leukocytosis may be absent in what patients that actually do have an infection
the elderly, ppl with severe sepsis
a patient has elevated WBC and high fever
is it a fever
cant say for sure
both of these could be due to other factors, but could very well also be a fever
which particular WBC are high in a patient with a BACTERIAL infection
neutrophils
in the case of a bacterial infection, a CBC with differential will usually have neutrophils greater than _____%
80%
what will the neutrophil bands be like in a patient with a bacterial infection
greater than 10% (immature)
making neutrophils so quickly to fight the infection
which WBC are high in parasitic infections and allergic reactions
eosinophils
which WBC are typically high in viral or fungal infections
lymphocytes
which WBC are typically high in chronic infections
monocytes
what are “segs and bands”
segs = mature neutrophils
bands = immature neutrophils (will be greater than 10% in bacterial infection)
name 2 biomarkers of infection that are nonspecific markers of inflammation
they are not used to ____, but used to ____
CRP and ESR
not used to confirm infection, but for monitoring (ie - osteomyelitis)
for ex, monitoring if the patient is responding to the antibiotic – want to make sure pt is improving and inflammation going down
normal CRP
less than 10ng/mL
normal ESR for men vs women
men - less than 22mm/hr
women less than 29
what biomarker is a marker for sepsis and what is norm value
LACTATE
0.5-1mmol/L
what is a marker of inflammation what is more specific for bacterial infections
it is a tool used to ____________
procalcitonin
tool used to discontinue antibiotics
how is lactate a marker for sepsis
bc high in impaired tissue oxygenation – happens when pt is septic
important consideration when using markers
NEVER used as sole evidence to diagnose infection
tissue or fluid samples can be used to see the presence of _________________
which particular fluids can be tested
WBC and bacteria
sputum, urine, spinal or joint fluid – pretty much anything can be cultured
how are X-rays, CT scans, MRIs, and echos used in diagnosing infection
for signs of inflammation like infiltrate and fluid
name 3 things that can be looked at to find out the SEVERITY of the infection
hemodynamic changes like change in heart rate and blood pressure
respiratory changes like SOB, rapid breathing
neurologic issues like lethargy, altered mental status, confusion
as mentioned, hemodynamic changes such as blood pressure can be used to estimate the severity of the infection
a low blood pressure could indicate what
sepsis
pt has dysuria, flankpain, and abnormal urinalysis
where is infection
urinary tract
pt has headache, altered mental status, +LP
CNS infection (meningitis)
+LP means positive lumbar culture
pt has cough, chest pain sputum, +CXR
lung infection
+CXR = infiltrates in chest XRAY
pt has fever, heart murmer, +blood cultures and + TTE
+TTE = trans thoracic echo
heart infection (endocarditis)
+ blood cultures means bacteremic!!!!
pt has pain at IV site, swelling, and erythema and + cultures
IV site infection
why is it important to know where the infection is
may need more than just antibiotics to treat
for EX if IV line infection - need AB and need to take the line out
also if endocardidits, may need surgery to remove the vegitation – antibiotics alone isnt gonna work
“non lactose fermenting, gram negative rods”
suggests what bacteria??
pseudomonas aeruginosa
is e coli gram positive or negative??
lactose fermenting or non lactose fermenting
negative
lactose fermenting
staph aureus and strep pneumoniae are gram positive or negative
positive
“gram positive cocci in clusters”
suggests what bacteria
staph species (staph aureus or epidermidis)
differentiate between the pathogenecity of staph aureus vs staph epidermidis
staph aureus is always a true pathogen
staph epidermidis may not always be a true pathogen – its normally all over skin
how do streptococcus species grow
in chains or pairs
NOT clusters like staph
name the 4 nonsterile specimen types, meaning that it’s normal for them to contain bacteria and the presence of bacteria does not indicate an infection
stool
throat swab
wound swab
genital swab
may not be reliable
is sputum considered a sterile specimen
only deep sputum
explain when and how blood cultures should be collected
2 sets and from 2 different body sites
each set has aerobic and anaerobic bottle
collect when pt is acutely ill bc the yield is higher, and incubate 5-7 days (may be longer for fungus)
MUST BE STERILE
explain how sputum cultures should be obtained
first rinse mouth with water
pt should breathe deep and cough several times to get DEEP SPECIMEN - more reliable - into a dry sterile container
if a pt is unable to give a high quality sputum sample, what can be done?
get induced sputum
explain how urine cultures should be obtained
catch midstream!! or straight catherization if pt cant pee
do NOT collect urine from the bag of an indwelling catheter - not reliable. use a needle to aspirate directly from the tubing instead
difference between urine dipstick and urinalysis
urine dipstick is rapid screening - shows leukocytes, nitrites, blood, etc
urinalysis w microscopy shows appearance, bacteria, WBC, epithelial cells, and RBC
why do urine dipsticks detect nitrites
some bacteria (like e. coli) convert nitrate (normally in urine) to NITRITE - therefore, can be marker of bacterial infection
bacterial specimen is treated with crystal violet and then iodine
when the iodine is washed off, what will the difference be between gram (+) vs gram (-) bacteria
in gram positive, the color will remain and the counter stain won’t do anything - it will still be purple BC OF THICK CELL WALL
in gram negative, the color will WASH OFF and the counter stain (safranin) will make it pink - bc peptidoglycan layer is covered by outer membrane and the cell wall is very thin
what is the first clue to determine the type of organism involved in causing the infection
gram stain with microscopy
can see if (+) or (-), can show number of organisms, and the type of cells present (ie: WBC, epithelial cells)
gram positive cocci that grows in chains and pairs
name 2 potential bacteria
enterococci and streptococci
gram positive bacilli that grow in rods
name 2 potential bacteria
listeria
corynebacterium
why do we care if there are epithelial cells in our sample of urine
poor quality sample - not catching good midstream void
sputum or blood culture has a lot of epithelial cells
good or bad sample
bad
staph epi can be called coagulase __________. why?
coagulase negative
it can sometimes be a contaminant
true or false
corynebacterium and listeria are anaerobic gram positive rods
FALSE
all true but they’re AEROBES
are strep and staph aerobic or anaerobic
aerobic
gram positive cocci anerobes
peptococcus and peptostreptococcus (NOT STAPH - THEY’RE AEROBES)
anaerobic gram positive bacilli (rods)
clostridium
(NOT corynebacterium or listeria - they’re aerobic)
gram negative aerobes that grow in rods and are lactose fermenting
e. coli
enterobacter
klebsiella
gram negative bacilli (rods) aerobes that are non lactose fermenting
THINK NOSOCOMIAL
pseudomonas and acinetobacter
aerobic gram negative cocci
neisseria
N. gonorrhoeae
h. influenzae
gram negative anaerobes that grow in rods are typically part of……
name 3 of them
our gut!
bacteroides
fusobacterium
prevotella
name 3 ATYPICAL bacteria that are not gram (+) or (-)
they are common in what infection
common in CAP
mycoplasma
legionella
chlamydophila
fungi infections are typically common in which type of patients
immunocompromised
gram positive cocci that grow in clusters
STAPH
gram positive cocci that grow in chains or pairs
streptococci, enterococci
gram negative rods, lactose fermenting
e. coli
enterbocater
klebsiella
gram negative rods, NON lactose fermenting
THINK NOSOCOMIAL
pseudomonas aeruginosa, acinetobacter
differentiate between a contaminate, colonizer, and pathogen
contaminate - introduced from external source due to poor technique or poor sample
colonizer - normal flora that does not cause harm
pathogen - damages the tissue and elicits a host response
“1/2 sets of blood cultures reveals gram positive cocci in clusters, coagulase negative”
this is staph epidermidis!!!
coagulase negative is the giveaway
must be a contaminent - repeat the sample. only grew in 1/2 and staph epi is normally on the skin
staph epi loves to grow on….
medical devices
give an example of a risk factor that may make a person prone to a real staph epi infection
IV drug use
which covers pseudomonas
pipercillin-tazobactam
vancomycin
pipercillin-tazobactam
name 2 of the most common antibiotics used in practice to cover pseudomonas
pipercillin-tazobactam and cefepime (3rd gen cephalosporin)
