Cumulative Final Exam Flashcards
What is PK?
What our bodies do to the antimicrobrials
Absorbtion, Distribution, Metabolism, Excretion
What is PD?
in regards to microbiology
What the antimicrobrials do to the pathogen
links drug exposure to microbiological and/or clinical effect
Gram Positive
Staphylococcus Coagulase (-) Organisms
Catalase + “clusters”
S. Epidermis
S. Saprophyticus
S. lugdunesis
S. Haemolyticus
S. Hominis
S. Warneri
Commonly live on human skin
Gram Positive
Staphylcoccus Coagulase (+) Organisms
Catalase + “clusters”
S. Aureus
important
note: MRSA is methicillin-resistant staph aureus
Gram Positive
Streptococcus Hemolysis α Organisms
Catalase - “pairs/chains”
S. pneumoniae
there are others but we never rlly discussed
Gram Positive
Steptococcus Hemolysis γ Organisms
Catalase - “pairs/chains”
Enterococci:
- E. Faecalis
- E. Faecium
Group D Strep
Gram Positive
Streptococcus Hemolysis β Organisms
Catalase - “pairs/chains”
Group A Strep = S. pyogenes
Group B Strep: S. agalactiae
Group C/G Strep = S. Dysgalactiae
Gram Negative
Enterobacterales Organisms
Escherichia spp.
Klebsiella spp.
Plesiomonas spp.
Enterobacter spp.
Citrobacter spp.
Salmonella spp.
Shigella spp.
Proteus spp.
Providencia spp.
Serratia spp.
Edwardsiella spp.
Yersinia spp.
Morganella spp.
Hafnia spp.
Gram Negative
Lactose Fermenting Spot Indole (+) Organisms
Escherichia coli
Klebsiella oxytoca
Gram Negative
Lactose Fermenting Spot Indole (-) Organisms
Enterobacter cloacae
Citrobacter freundii
Klebsiella aerogenes
Klebsiella pneumoniae
Gram Negative
Non-Lactose Fermenting Oxidase (+) Organisms
Pseudomonas
Vibrio
Aeromonas
Flavobacterium
Alcaligenese
Plesiomonas
Chromobacterium
Gram Negative
Non-Lactose Fermenting Oxidase (-) Organisms
Acinetobacter
Salmonella
Shigella
Serratia
Edwardsiella
Yersinia
Morganella
Hafnia
Gram Stain Tells us
Determines Cell Wall Form
gram positive: stains purple
gram negative: stains pink/red
other: stains clear
Gram Stain Tells us
Determines morphology (shape)
cocci, bacilli, or other
Gram Stain tells us
Acceptability of specimen
If site is non-sterile than other organisms will likely present
Gram Stain Tells us
Quantification of Bacteria
is there a lot of bacteria? or not too much?
a lot of WBC= infection
a lot of epithelial cells= bad sample
What is Bactericidal?
Kills organism through the action of antimicrobrial
What is Bacteriostatic?
Halts organism growth through the action of the antimicrobrial
Is Bacterio- static or -cidal better?
Depends on the concentration!
- Low concentrations of -cidal drugs can be -static
- High concentrations of -static drugs can be -cidal
What is Broad Spectrum Activity?
Antimicrobrial targets many types of pathogens
What is Narrow Spectrum Activity?
Target only a few types of pathogens
What is Empiric Antimicrobrial therapy?
therapy that is started before pathogen and susceptibility are known because
- culture results are nto available/complete
- antimicrobrial susceptibility is not known
What is Definitive Antimicrobrial therapy?
Therapy that is started after pathogen and susceptibility is known. AKA “directed therapy” or “step-down therapy”
Frequent Blood Culture Contaminants
Staph Epidermis: skin cells
Corynebacterium spp.
Bacillus spp.
Cutibacterium acnes
Micrococcus spp.
Common skin cell contaminants when we see these we don’t always treat
NEVER Blood Culture Contaminants
always represent true infection
Staph aureus, Staph lugdunensis, Gram-negatives, some anaerobes, Yeast
ALWAYS TREAT THESE ORGANISMS
What to consider when there is a blood culture contaminant
- What is the clinical status of patient? Do they seem sick?
- Is this a common contanimant?
- Do they have an indwelling medical device
- Repeat the culture in another location - is the contaminant still there?
- Is it taking a long time for the organisms to grow?
- Are all the blood culture bottles positive?
What is Antimicrobrial Resistance?
The antimicrobiral concentration below that MIC at which a typical patient will usually respond given a typical dose
pathogens gain the ability to not be killed by drugs at safe doses
Intrinsic Resistance
Natural resistance of microbes to antimicrobrials
Resistance microbes are born with and is always expressed within species
Acquired Resistance
Obtained resistance of microbes to antimicrobrials -
Resistance microbes obtain to antimicrobials they were prevously susceptible to
big purple chart
Methicillin-resistant Staphylococcus Aureus Treatments
Vanc (+13), Dappin up Lids, Caroline D’alba, Teleports Over Prissy Tigers& Teachers, Temporarily Clinching Rifle Delays
big purple chart
Vancomycin-resistant Enterococci Treatment
Dappin up Lids Over Prissy TIgers& Frostbite Nights
big purple chart
Atypicals Treatment
Fuck My Teachers
lol not actually
big purple chart
P. Auruginosa Treatment
Piper Aztec Amber Loves Delays ,
Polly Cips Cefs & Carbs
big purple chart
Anaerobe Treatment
Piper Aims Amps ox&teet Carb Make Metro Tigers Delay
big purple chart
Carbapenem-resistant Enterobacterales Treatment
Only drug that treats this one and not others
Meropenem-vaborbactam
big purple chart
pAMPC- Type Cephalosporinase Producing Organisms Treatment
ones that only treat amp c
Cefepime and TMP-SMX
bIg purple chart
Extended Spectrum Beta Lactamase Producers Treatment
ones that only treat ESBL
Ceftolozane-tazobactam, Nitrofurantoin, Fosfomycin
big purple chart
Treats ESBL and AmpC
Carbapenems/BLI and Fluoroquinolones
big purple chart
Treats ESBL, AMPc, and CRE
only ones that treat all 3
Polly & Amber Cef Tigers
What is Zone of Inhibition?
qualitative way to measure the activity of drug. organism grows on top of media and antibiotic diffuses on plate for 18-24 hours
↑zone of clearance = ↑antimicrobial activity
What is MIC?
Lowest concentration of given antimicrobial that will inhibit the visual growth of an organism after 18-24h incubation.
↓ MIC = ↑ antimicrobial activity
4 Methods of Susceptibility Testing
Qualitative:
1. Disk Diffusion
**Quantitative: **
2. Broth Dilution
3. Etest (agar diffusion)
4. Automated susceptibility testing
What is the relationship between zone of inhibition and MIC
Inverse relationship
↓ MIC = ↑ zone of inhibition
Susceptibility
Susceptible Interpretation
antimicrobrial concentration is ABOVE the MIC
Susceptibility
Intermediate Interpretation
antimicrobrial concentration is close to the MIC
Susceptibility
Resistant Interpretation
antimicrobrial concentration BELOW the MIC
What are Local Antibiograms?
Overall antimicrobrial susceptibility profile of specific microorganisms to various antimicrobrials (typically at your hospital)
Informs the clinician of local institutional patterns and thus inform empiric antimicrobrial precribing patterns while we wait for culture results
↑ percentage = ↑ susceptible
What does MRSA mean?
Methicillin-resistant Staphylococcus Aureus
OR Nafcillin OR Oxacillin
What does MSSA mean?
Methicillin-susceptible Staphylococcus Aureus
OR Nafcillin OR Oxacillin
What does it mean if resistance report says: “S. aureus, mecA positive or PBP2a”
MRSA
Enterococcus Faecalis vs. Enterococcus Faecium
Faecalis is more common and less drug resitant
Faecium is less common and more drug resistant
Enterococcus Faecalis Treatment
Ampicillin
Streptococcus Pyogenes Treatment
Penicillin
has absolutely no resistance to penicillin
~gram positive~
Necrotizing Faciitis Treatment
Cell wall active agent (penicillin) plus toxin-inhibiting antibiotic (clindamycin)
Streptococcus Pneumoniae Treatment
- Penicillin
- 3rd Gen Cephalosporins: cefdinir, ceftriaxone, etc.
- Fluoroquinolones
- Vancomycin (highly resistant strains)
- Vaccines: PCV13 (prevnar) and PPV23 (pneumovax)
~gram positive~
Clostridioides Difficile Treatment
Oral Vancomycin
and discontinue offending antibiotic
- fidaxomicin
- metronidazole
- fecal transplant
C. diff risk factors
- exposure or previous history
- older age
- recent hospitalization
- immunocompromising conditions
- CLINDAMYCIN
- fluoroquinolones, carbapenems, 3rd/4th gen cephalosporins
C. diff is gram positive
Enterobacterales Treatment
varies with type/severity of infection, patient history, abx susceptibility
- pipercillin/tazobactam
- ceftriaxone
- cefepime
- carbapenems
- fluoroquinolones
- nitrofurantoin
What is the most common Gram (-) Non-lactose fermenting organism?
Pseudomonas aeruginosa
found in skin/soft tissue, urinary tract, & eye/ear infections
Yeast is divided into:
Candida Species and Cryptococcus Species
What are the candida species?
C.:
albicans, glabrata, parapsilosis, tropicalis, krusei, lusitaniae
What are the cryptococcus species?
C. neoformans
What are the Dimorphics?
Coccidoides immitis, Blastomyces dermatidis, Histoplasma capsulatum