Infectious Disease Flashcards
Which organism has a thick cell wall, stain dark purple or bluish from the crystal violet stain
Gram +
Which organism have a thin cell wall and take up the safranin counterstain, resulting in a pink or reddish color
Gram -
Which organisms do not have a cell wall and do not stain well
Atypical
Intrinsic resistance
the resistance is natural to the organism. For example, E. Coli is resistant to vancomycin b/c this abx is too large to penetrate the bacterial cell wall of E. coli
Selection pressure
resistance occurs when abx kill off susceptible bacteria, leaving behind more resistant strains to multiply. For example, normal GI flora includes Enterococcus. When abx (vancomycin) eliminate susceptible Enterococci, vancomycin-resistant enterococcus (VRE) can become predominant
Enzyme inactivation
enzymes produced by bacteria break down the antibiotic
ex. beta-lactamase
List beta-lactamase inhibitors (5)
clavulanate
sulvactam
tazobactam
avibactam
ESBLs
- breakdown?
- treatment (2)
break down all PCN and most cephalosporins
treatment: Carbapenems, newer cephalosporin/beta-lactamase inhibitors
CRE
- breakdown?
- treatment (2)
MDR Gram- organisms (Klebsiella spp., E. coli) that produce enzymes (e.g carbapenemase) capable to breaking down penicillins, most cephalosporins, and carbapenems.
Treatment: polymyxins, ceftazidime/avibactam (avycaz)
common resistant pathogens
Kill Each And Every Strong Pathogen Klebsiella pneumonia (ESBL, CRE) E. Coli (ESBL, CRE) Acinetobacter baumannii Entercoccus faecalis/faecium (VRE) Staphlococcus aureus (MRSA) Pseudomonas aeruginosa
Folic acid synthesis inhibitors (3)
Sulfonamides
trimethoprim
dapsone
Cell wall inhibitors (3 classes)
beta-lactams (pcns, cephalosporins, carbapenems)
monobactams (aztreonams)
vancomycin, dalbavancin, telavancin, oritavancin
protein synthesis inhibitors (6)
aminoglycosides macrolides tetracyclines clindamycin linezolid, tedizolid quinupristin/dalfopristin
Cell membrane inhibitors (4)
polymyxins
daptomycin
telavancin
oritavancin
DNA/RNA inhibitors (3)
Quinolones (DNA gyrase, topoisomerase IV)
Metonidazole, tinidazole
Rifampin
concentration-dependent killing (3)
aminoglycosides
quinolones
daptomycin
AUC:MIC killing (4)
Vancomycin
macrolides
tetracyclines
polymyxins
time-dependent killing (1)
beta-lactams (pcns, chephalosporins, carbapenems)
MOA of beta-lactam antibiotics
they have a beta-lactam ring and inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). prevents the final step of peptidoglycan synthesis in bacterial cell walls
Natural penicillins coverage (2)
Gram + cocci
-Streptococci, Enterococci, NOT staphylocci
Gram + anaerobes (mouth flora)
Aminopenicillins coverage
all the same as natural pcns
+
Gram - (HNPEK)
Haemophilus, Neisseria, Proteus, E. coli, Klebsiella
Aminopenicillins + beta-lactamase coverage
added activity to MSSA
more resistant strains of gram - (HNPEK)
Gram - anaerobes (B. fragilis)
Extended-spectrum PCN coverage
broad coverage all same coverage as aminopcn \+ Gram - bacteria -Citrobacter, Acinetobacter, Providenia, Enterobcter, Serratia (CAPES) and pseudomonas
Antistaphylococcal PCN coverage
streptococci
enhanced activity to MSSA
lack activity to Enterococcus, Gram -, and anaerobes
Natural PCN (1)
Penicillin
Aminopenicillins (2)
Amoxicillin
Ampicillin
Aminopenicillins + beta-lactamase (2)
Augmentin
-amoxicillin/clavulanate
Unasyn
-ampicillin/sulbactam
Extended spectrum PCN (1)
zosyn
-piperacillin/tazobactam
Antistaphylococcal PCN (3)
Dicloxacillin
Nafcillin
Oxacillin
What class of abx increases risk of seizures if accumulation occurs (with renal failure)
Penicillins
first-line treatment for strep throat and mild nonpurulent skin infections
Penicillin VK
First-line treatment for acute otitis media
amoxicillin
DOC for IE prophylaxis before dental procedures
Amoxicllin
First-line for acute otitis media and for sinus infections
Augmentin
DOC for syphilis
Penicillin G Benzathine
Which PCN is not for IV because can cause death
Penicillin G Benzathine
Only PCN active against Pseudomonas
Zosyn
Which PCN cover MSSA only no MRSA
Nafcillin, Oxacillin, Dicloxacillin
Which PCN have no renal dosage adjustments
Nafcillin, oxacillin, dicloxacillin
Cephalosporins as a class are not active against (2)
Enterococcus or atypical
1st Generation cephalosporins coverage (3)
Gram + (stretococci and staphylocci)
MSSA
Gram - Rods (Proteus, E. coli, Klebsiella) (PEK)
Which generation has the least Gram - coverage
1st generation
2nd generation cephalosporin coverage
2 types
- Cefuroxime: staphylocci, HNPEK
- Cefotetan, Cefoxitin: also Gram - anaerobes (B. fragilis)
3rd generation cephalosporin coverage
2 groups a) ceftriaxone, cefotaxine, and oral drugs -more resistant Strep (s. pneumo, viridans) - MSSA - Gram + anaerobes (mouth flora) - more resistant HNPEK b) ceftazidime - lack Gram + coverage - Pseudomonas ceftazidime/avibactam, ceftolozane/tazobactam - also MDR pseudomonas - also NDR Gram - Rods
4th generation cephalosporin coverage
broad Gram - activity (HNPEK, CAPES, pseudomonas)
Gram + coverage similar to ceftriaxone
5th generation cephalosporin coverage
Gram - activity similar to ceftriaxone
broad gram + activity
only beta-lactam to cover MRSA
1st generation cephalosporins (3)
cefazolin
cefhalexin
cefadroxil
2nd generation cephalosporins (5)
cefuroxime cefotetan cefaclor cefoxitin cefprozil
3rd generation cephalosporins group 1 (7)
cefdinir ceftriaxone cefotaxime cefditoren cefixime cefpodoxime ceftibuten
3rd generation cephalosporins group 2 (3)
ceftazidime
ceftazidime/avibactam
ceftolozane/tazobactam
4th generation cephalosporins (1)
cefepime
5th generation cephalosporins (1)
ceftaroline
cephalosporins have a cross-reactivity with what allergy
PCN
common use of cephalexin (2)
skin infection: MSSA
strep throat
common use of cefuroxime (3)
acute otitis media
CAP
sinus infection
common use of cefdinir (2)
CAP
sinus infection
common use of cefazolin
surgical prophylaxis
cefotetan and cefoxitin have what abnormal coverage
B. fragilis (anaerobic coverage)
common use for cefotetan and cefoxitin
surgical prophylaxis (colorectal)
what cephalosporin can have a disulfiram-like reaction with alcohol
cefotetan
common use of ceftriaxone and cefotaxime (4)
CAP
meningitis
SBP
pyelonephritis
Does ceftriaxone have renal dose adjustment
No
what is the only beta-lactam active against MRSA
ceftaroline
Carbapenem coverage (2) No coverage (5)
most Gram + & Gram -
anaerobic pathogens
NO atypical, MRSA, VRE, C. diff, stenotrophomonas
Ertapenem has no activity to? (3)
Pseudomonas
Acinetobacter
Enterococcus
carbapenem caution in which population
dec. seizure control
All carbapenems cover what two organisms
ESBLs
pseudomonas-except ertapenem
All carbapenems do not cover (5)
atypicals VRE MRSA C. diff stenotrophomonas
Name monobactams (1)
aztreonam
MOA of aztreonam
inhibits bacgerial cell wall synthesis by binding to penicillin binding proteins which prevents teh inal step of peptiodglycan synthesis in bacterial cell walls. The monobactam structure makes cross-reactivity with a beta-lactamallergy unlikely
Aztreonam activity
many Gram -
Pseudomonas
No Gram +
Aminoglycoside MOA
bind to the ribosome which intereferes with bacterial protein synthesis and results in a defective bacterial cell membrane
Aminoglycoside coverage
Gram - , pseudomonas
traditional dosing for aminoglycosides
lower doses more frequently
Extende interval dosing for aminoglycosides
higher doses to attain higher peaks less frequently this decreases nephrotoxcity
toxicity of aminoglycosides (2)
nephrotoxicity
ototoxicity
list carbapenems (4)
doripenem
imipenem/cilastin
meropenem
ertapenem
Aminoglycoside dose adjustment on body weight
underweight: use total body weight
obese: use addjusted body weight
Quinolone MOA
inhibit bacterial DNA topoisomerase IV and DNA gyrase (topoisomerase II) inside the bacteria. this prevents supercoiling of DNA and promotes breakage of double-stranded DNA
Respiratory quinolones (3) why are they called this?
gemifloxacin
levofloxacin
moxifloxacin
-b/c enhanced coverage of S. pneumonia and atypical coverage
which quinolones cover pseudomonas
ciprofloxacin
levofloxacin
Which quinolone cannot treat UTIs
Moxifloxacin
Which quinolone has acitivity against MRSA
Delafloxacin
Quinolones and warfarin
inc. warfarin concentration
Quinolones and hypoglycemic drugs
inc. effects of hypoglycemic drugs
Antipseudomonal Quinolones (2)
ciprofloxacin
levofloxacin
Macrolides MOA
bind to the 50s ribosomal subunit resulting in inhibition of RNA-dependent protein synthesis
Macrolides coverage
atypicals -legionella -chlamydia -mycoplasma -mycobacterium avium complex Haemophilus
Macrolides are common treatment for (2)
CAP
STIs (chlamydia, gonnorrhea)
List macrolides (3)
azithromycin
clarithromycin
erythromycin
tetracycline MOA
inhibit bacterial protein synthesis by reversibly binding to the 30s ribosomal subunit
Tetracyclines coverage
Gram + (staph, trep, enterococci, nocardia, bacillus, propionibacterum)
Gram - including respiratory flroa (Haemophilus, Moraxella, atypicals)
spriochetes
rickettsiae
Bacillus anthracis
treponema
Doxycycline indications
RTI (CAP) tick/rickettsial disease STI MRSA skin infection VRE UTI
Minocycline indications
skin infections including acne
What is one major caution in using a tetracycline
do not use in those <8 years can suppresses bone growth and skeletal development and permanently discolors teeth
Sulfonamides MOA
inhibit dihydrofolic acid formation from para-aminobenzoic acid, which interferes with bacterial folic acid synthesis
Trimethoprim MOA
inhibits dihydrofolic acid reduction to tetrahydrofolate, resultin gin inhibition of the folic acid pathway
Bactrim coverage
staphlyococci (MRSA, CA-MRSA) S. pneumoniae Gram - (broad) Shiqella Salmonella Stenotrophomonas opportunisitc pathogens (nocardia, pneumonocytis, toxoplasmosis) NO coverage: psedumonas, enterococci, anaerobes
Bactrim & Warfarin
INR increased when used with warfarin
glycopeptide MOA
inhibit bacterial cell wall synthesis by binding to the D-alanyl-D-alanine cell wall precursor and blocking peptidoglycan polymerization
Vancomycin coverage
Gram + only
-MRSA, streptococci, enterococci (not VRE), C. difficile
lipoglycopeptides MOA
inhibit bacterial cell wall synthesis by binding to D-alanyl-D-alanine portion of cell wall, blocking plymerization and cross-linking of peptidoglycan and disrupting bacterial membrane potential and changing cell permeability
List lipoglycopeptides (3)
telavancin
oritavancin
dalbavancin
Daptomycin coverage
Gram + (MRSA, enterococci [VRE])
Which condition can daptomycin not be used
pneumonia b/c due is inactivated by lung surfactant
Oxazolidinones MOA
bind to the 50s subunit of te bacterial ribosome, inhibiting translation and protein synthesis
Oxazolidinones list (2)
linezolid
tedizolid
Oxazolidinones coverage
Gram + and VRE
Quinupristin/dalfopristin MOA
bind to the 50s ribosomal subnit inhibiting protein synthesis
Quinupristin/dalfopristin coverage
Gram + (MRSA, VRE not E. faecalis)
Tigecycline MOA
binds to the 30s ribosomal subnit inhibitin gprotein synthesis, structurally related to the tetracycliens
Tigecycline coverage
Gram + (MRSA, VRE)
Gram - (no activity against the 3Ps: pseudomonas, proteus, providenica)
anaerobes
atypical
Tigecycline indication (3)
SSTi
IAI
CAP
list polymyxins (2)
colistin
polymyxin B
polymyxin coverage
Gram -
Chloramphenicol MOA
binds to 50s subunit jof bacterial ribosome inhibiting protein synthesis
Chloramphenicol coverage
Gram + & Gram -
anaerobes
aytpical
Clindamycin MOA
reversibly binds to the 50s subunit of the bacterial ribosome inhibiting proetin synthesis
Clindamycin coverage
anaerobes
Gram +
NOT cover: Enterococcus, Gram -
Metronidazole MOA
cause a loss of helical DNA structure and strand breakage resulting in inhibition of protein synthesis
Metronidazole coverage
anaerobes
protozoal infections
Fidaxomicin MOA
inhibits RNA polymerase, resulting in inhibition of proetin synthesis and cell death
Fidaxomicin indication
C. diff
Rifaximin MOA
inhibits bacterial RNA synthesis by binding to bacterial DNA-dependent RNA polymerase
Rifaximin coverage
E. Coli
Fosfomycin MOA
inhibits bacterial cell wall synthesis by inactivating the enzyme pyruval transferase which is critical in the synthesis of cell walls
Fosfomycin Indication
UTI
Fosfomycin coverage
E. coli (ESBL)
E. Faecalis (VRE)
Nitrofurantoin MOA
bacterial cell wall inhibitor
Nitrofurantoin indication
uncomplicated UTI
Nitrofurantoin coverage
E. coli klebsiella Enterobacter S. aureus Enterococcus (VRE)
Nitrofurantoin Contraindication
CrCl < 60
Mupirocin ointment indication
eliminate staphylcocci MRSA colonization of the nares
Do lipophilic or hydrophilic antimicrobials have better tissue penetration
lipophilic