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
What are the Molds?
Aspergillus fumigatus, Zygomycetes (Mucor), Fusarium spp., Scedosporium spp.
Fuck (fusarium)
Zach’s (zygo)
Ass (asp) has
Skid marks (sced)
What are primary yeast pathogens?
can infect otherwise normal and healthy hosts
What are opportunistic yeast pathogens?
typically require “abnormal/immunocompromised” hosts to establish infection
ex: Candida spp. or Cryptococcus neoformans
Which is the most prevalent fungal infection?
Candida albicans
- associated with UTI’s, candidemia, CNS candidiasis, endocarditis
Risk factors for Invasive Candidiasis
immunosuppression, central venous catheters, surgery, paranteral nutrition, neutropenia, renal replacement therapy in ICU, implantable prosthetic devices, broad spectrum antibiotics
Candida spp. Oropharyngeal Infections
AKA thrush
- typically caused by C. albicans
- Sx: white patches in mouth
- Tx: swish and swallow and rinse mouth after ICS
Candida spp. Vulvovaginal Infections
AKA yeast infection
- Sx: itching, redness, irritation, cottage cheese discharge
- Tx: “One and done” dose of fluconazole!
we familiar unfortunately
Candida spp. UTI
AKA Candiduria (rare compared to bacterial UTI)
- Sx: cystitis, blood in urine
- Dx: symptoms and urine culture
- must distinguish colonization vs. infection
Candida spp. Bloodstream Infections
AKA candidemia
- more common in hospital
- Sx: high fever, chills, malaise, sepsis
- Dx: blood culture
- never a contaminant!!!
Candida spp. Treatments
C. albicans (fluconazole-susc), C. lusitaniae, C. parapsilosis, C. tropicalis, C. glabrata (flu-susc) = fluconazole
C. albicans (fluconazole-res), C. glabrata or C. krusei (fluconazole-res) = Echinocandin or Amphotericin B
usually start more empiric & eventually move to fluconazole if possible
Fluconazole-susceptible Treatment normal dosing
800 mg (or 12 mg/kg) loading dose
400 mg (6 mg/kg) once daily
C. glabrata (fluconazole-susceptible dose dependent) dosing
800 mg (12 mg/kg) once daily
Fluconazole PK/PD
The AUC and dose have a linear relationship, so when giving a dose you can assume the AUC is the same
Cryptococcus neoformans
Opportunistic pathogen that affects the CNS and is typically acquired through inhalation of aerosolized cells from environment
Causes meningitis!
Cryptococcus neoformans treatment
Induction: liposomal amphotericin B + flucytosine for 2 weeks
Consolidation: Fluconazole for 8 weeks
Maintenance: Fluconazole for 12 months
More common opportunistic mold pathogens are?
Aspergillus spp. and Mucormycetes (zygo one)
Aspergillus spp. concepts
- opportunistic so host needs to be immunocompromised
- primarily inhaled
- aspergillosis is the fungal infection caused by pathogenand mortality is high!
Examples of immunosuppression risk factors for invasive Aspergillosis
- prolonged neutropenia
- allogeneic hematopoietic stem cell transplant
- solid organ transplant
- inherited/acquired immunodeficiencies
- immunosuppressie therapies (TNFalpha inhibitors and corticosteroids)
- others
Invasive Pulmonary Aspergillosis
- Most common in neutropenia or those recieving cytotoxic chemotherapy
- Sx: pulmonary infiltrates, pleuritic chest pain, hemoptysis, fever
- can range from mild to destructive
- Halo sign(early) and Air-crescent(late) sign can be seen on the computed tomography
Invasive Aspergillosis treatment
VORICONAZOLE!
Dimorphics Pathogenicity
Primary pathogens: Coccidoides immitis, Histoplasma dermatitidis, Blastomyces capsulatum
Endemic pathogens: cause disease via inhalation of spored from specific environmental/geographical locations
Where is Coccidoides spp. found?
Highly endemic in southwestern US (Arizona, New Mexico, California, Nevada, Texas, Utah)
AKA “valley fever” or Coccidioidomycosis
Coccidoidomycosis risk factors/treatment
Risk factors: ethnicity, 3rd trimester, males, cellular immunodeficiency, extremes of age
Treatment: mild forms may not need treatment but if needed fluconazole
Where is Histoplasmosis found?
highly endemic in Ohio and Mississippi River valleys
Where is Blastomycosis found?
highly endemic in Ohio, Mississippi River valleys, and Great Lakes
Histoplasmosis and Blastomycosis treatments
mild forms may not need treatment
mild-moderate: itraconazole
severe/disseminated: liposomal amphotericin B or itraconazole
What is a virus?
neither prokaryotic or eukaryotic
- non-living, intracellular parasites
- no organelles or ribosomes
- cannot make energy/proteins independently of a host cell
- genomes may consist of RNA or DNA (NEVER BOTH)
- morphology: naked capsid or envelope
How are viruses classified?
structure, biochemical characteristics, disease, means of transmission, host range, tissue or organ
Steps in Viral Infection of Host Cell
IN ORDER
- Recognition of target cell
- attachment
- penetration
- uncoating/release of genome
- transcription
- protein synthesis
- replication of genome
- assembly of virus
- lysis of naked capsid viruses or budding of enveloped viruses –> release
What are the Nucleoside Analogs?
- Acyclovir
- Valacyclovir
- Ganciclovir
- Valganciclovir
What is the Nucleotide Analog
Cidofovir
What is the Pyrophosphate Analog?
Foscarnet
What is the CMV DNA Terminase Complex Inhibitor
Letermovir
What is the Neuraminidase Inhibitor?
Oseltamivir
HSV-1 and HSV-2
Herpes Simplex Type 1 and 2
Spreads through close contact (STD)
Subfamilies: HHV-1 and HHV-2
Targets mucoepithelial cells
VZV
Varicella-zoster virus
subfamily: HHV-3
spreads through respiratory and close contact
Targets mucoepithelial cells and T-cells
EBV
Epstein-Barr virus
subfamily: HHV-4
spreads through saliva (its mono)
targets B-cells and epithelial cells
Cytomegalovirus
subfamily: HHV-5
spreads through close contact (STD), transfusions, tissue transplants, and congenital
targets monocytes, granulocytes, lymphocytes, and epithelial cells
HSV triggers
- Ultraviolet B radiation (skiing, tanning)
- Fever
- Emotional stress
- Physical stress
- Menstruation
- Foods (spicy, allergic, acidic)
- Immunosuppression
basically body stresses
Orolabial and Mucocutaneous HSV
Clear vesicles that rapidly ulcerate
Sx: soreness, burning sensation, tingling, blisters, rashes
Dx: PCR
Tx: topical meds, oral acyclovir or valacyclovir
recurrences are normal
Genital HSV
Grouped 2-4 mm vesicles with underlying erythema that progress to ulcers
Sx: super painful ulcers/lesions, fevers, headache, myalgias
Dx: PCR
Treatment: oral acyclovir or valacyclovir
Varicella (Chickenpox)
Caused by Varicella Zoster
-more common in children
Tx immunocompetent: supportive care
Tx immunosuppressed: acyclovir, valacyclovir
Herpes Zoster (Shingles)
Results from reactivation of a patients latent virus acquired earlier in patients life
- severe pain precedes appearance of chicken pox-like lesions and can be fatal in immunocompromised
- Tx: Acyclovir or Valacyclovir and potentially analgesic for neuralgia
- Immunity wanes in elderly population so more common for them to get it
- lesions are viable virus so be careful around non-immune
Varivax Vaccine treats
Chickenpox
live attenuated vaccines
ProQuad Vaccine treats
Chickenpox
Live attenuated vaccine
Shingrix treats
Shingles
Inactivated Vaccine
Most novel coronavirus is?
SARS-CoV-2: virus name
COVID-19: disease name
What are the 4 structural proteins of SARS-CoV-2?
- Spike protein: Vaccines work with this one. It mediates binding and fusion with host cell membrane. Forms the crown.
- Membrane protein: viral assembly
- Envelope protein: transmembrane protein
- Nucleocapsid protein: forms nucleocapsid
COVID-19 Therapies
- monoclonal antibodies
- dexamethasone
- remdesivir
- paxlovid
- molnupiravir
COVID-19
Remdesivir indications
antiviral: nucleotide analog prodrug
IV only
use in hospitalized patients requiring oxygen
COVID-19
Dexamethasone indications
corticosteroid
use in hospitalized patients requiring oxygen, mechanical ventilator support, or extracorporeal membrane oxygenation
COVID-19 Tx WE DON’T USE
hydroxychloroquine and ivermectin
COVID-19
Pfizer-BioNTech Vaccine
mRNA
MOA: encodes the prefusion spike glycoprotein of SARS-CoV-2
COVID-19
Moderna Vaccine
mRNA
MOA: encodes the prefusion spike glycoprotein of SARS-CoV-2
COVID-19
Janssen (J&J) Vaccine
Replication-incompetent adenovirus vector
MOA: vector expresses the SARS-CoV-2 spike glycoprotein
What is Antigenic drift?
small mutations in the genes that lead to changes in surface proteins of the virus
What is Antigenic shift?
Abrupt, major change due to reassortment that lead to changes in surface proteins of the virus
Influenza
“the flu”
Sx: malaise, headache, fever, chills, loss of appetite, weakness, fatigue
Tx: supportive care, Oseltamivir, Influenza cap-dependent endonuclease inhibitor
Influenza vaccine is recommended to?
Everyone at least 6 y/o once a year
What are the HIV risk factors?
- unprotected sex
- sharing contaminated injecting equipment
- accidental needle stick
How is HIV transmitted?
sexual contact, blood, breast milk, semen, vaginal secretions, and perinatal
HIV MOA
preferentially infects and kills helper T-lymphocytes (CD4+ cells) which results in a loss of cellular immunity and vulnerability to opportunistic infections
What is the HIV life cycle?
- Binding
- Fusion
- Reverse transcription
- Integration
- Replication
- Assembly
- Budding
HIV drug
What is an NRTI?
Nucleoside Reverse Transcriptase Inhibitor
- works on reverse transcription step
HIV drug
What is an NNRTI?
Non-nucleoside Reverse Transcriptase Inhibitors
HIV drug
What is an INSTI
Integrase inhibitors
HIV drug
What is a PI?
Protease inhibitor
How to diagnose HIV?
HIV serology: detection of Ab against virus
HIV viral load: amount of HIV in blood
CD4 cell count: indicator of HIV progression
HIV treatment
2 NRTI’s + INSTI or NNRTI or PI with PK enhancer
What is zoonoses?
diseases/infections naturally transmitted to humans from vertebrate animals either directly or indirectly through an insect vector
What does “vector-borne” mean?
When a blood-feeding arthropod is involved
ex: mosquito/tick
Dog Bite/Scratches organisms
Pasteurella canis or Pasteurella multocida
OR rarely Rabies lyssavirus
Cat bite organism
Pasteurella multocida
Cat scratch organism
Bartonella henselae
Small rodent bites organism
Streptobacillus moniliformis
Pasteurella canis and multocida Treatment
Amoxicillin/Clavulanate
Rabies treatment
Pre-exposure prophylaxis: rabies vaccine
Post-exposure prophylaxis: rabies vaccine + rabies immunoglobulin
Cat scratch disease treatment
Azithromycin +/- rifampin
or
Doxycycline +/- rifampin
reminder this is Bartonella henselae
Rabbit/muskrat/praire dog/ticks/deer flies organism
Francisella tularensis
Francisella tularensis treatment
Gentamicin or doxycycline
TIcks
Lyme Disease is caused by
Borrelia burgdorferi
ticks
Ehrlichiosis is caused by
Ehrlichia spp.
tick
Rocky Mountain Spotted Fever is caused by
Rickettsia rickettsii
How do you treat a tick-borne illness?
Doxycycline!
How do you get Toxoplasmosis?
CD4 counts <50-100
Cat feces
Eating undercooked meat
Gardening
Toxoplasmosis Prophylaxis and Treatment
Prophylaxis: TMP/SMX if CD4<100 and toxoplasma IgG is positive
Tx: Pyrimethamine + sulfadiazine + leucovorin
What is a Trophozoite?
Motile, active feeding stage of protozoa
Parasite
What is a Cyst?
Nonmotile, nonmetabolizing, nonreproducing form. This form is dormant and resting. This is how it can survive outside of the host.
Trichomonas vaginalis
one of the most common STD’s that infects squamous epithelium in the urogenital tract
- exists only in trophozoite form
- transmission is via sexual contact
Trichomoniasis treatment
Metronidazole whether asymptomatic or symptomatic
Malaria
Caused by Plasmodium and spreads to humans via Anopheles mosquitoes
4 different Malaria species
P. falciparum, P. vivax, P. ovale, P. malariae
Mild Malaria Treatment
Artemisinin-based combination therapy
Severe Malaria treatment
Start with Parentaral artesunate for 24 hours then complete treatment with artemisinin-based combination therapy
Enterobiasis
Pinworms
diagnosed by finding eggs on perianal tape swabs. eggs are rarely fond in stool.
Enterobiasis treatment
Albendazole
OTC: pyrantel pamoate
