Overview of Antimicrobial Agents Flashcards
Natural Penicillins
Penicillin G(IV, IM)
Penicillin V (PO)
Anti-staphylococcal Penicillins
Oxacillin(IV, IM)
Dicloxacillin(PO)
Nafcillin (IV, IM)
Aminopenicillins*
Ampicillin(PO, IV, IM)
Amoxicillin(PO)
Anti-pseudomonalPenicillins
Piperacillin (IV)
First Generation Cephalosporins
Cefazolin(IV, IM)
Cephalexin [Keflex] (PO)
Second Generation Cephalosporins
Cefoxitin(IV)
Cefuroxime (PO, IV, IM)
Third Generation Cephalosporins*
Ceftriaxone[Rocephin] (IV, IM)
Ceftazidime(IV, IM)
Fourth Generation Cephalosporins*
Cefepime(IV, IM)
Carbapenems
Imipenem/cilastatin (IV)
Meropenem(IV)*
Ertapenem(IV, IM)*
Monobactams
Aztreonam (IV, IM, INH)
B-lactamase Inhibitors*
Ampicillin-sulbactam(IV)
Amoxicillin-clavulanic acid [Augmentin] (PO)
Piperacillin-tazobactam(IV)
Glycopeptides*
Vancomycin(PO, IV)
Lipopeptides
Daptomycin(IV)
Fluoroquinolones
Ciprofloxacin [Cipro] (PO, IV, topical)
Levofloxacin(PO, IV, topical)*
Moxifloxacin (PO, IV, topical)
Aminoglycosides
Tobramycin (IV, IM, INH, topical)
Gentamicin(IV, IM, topical)*
Tetracyclines/Glycylcyclines
Minocycline (PO, IV)
Doxycycline(PO, IV)*
Macrolides/Ketolides
Clarithromycin (PO)
Azithromycin[Zithromax, Z-pak] (PO, IV, topical)*
Lincosamides*
Clindamycin[Cleocin] (PO, IV, IM, topical)
Sulfonamides/Trimethoprim
Sulfamethoxazole/trimethoprim (PO, IV)
Most common categories
penicillins and macrolides
Top 5 drugs:
Azithromycin Amoxicillin Amoxicillin-clavulanate Ciprofloxacin Cephalexin
Ask yourself whether an antimicrobial agent is warranted:
Is an antimicrobial indicated based on clinical findings?
Have appropriate cultures been obtained?
What is the most likely causative organism?
What must be done to prevent secondary exposure?
Is there clinical evidence or established guidelinesthat have determined antimicrobial therapy provides a clinical benefit?
prophylaxis
no infection
pre-emptive
infection
empiric
symptoms
definitive
pathogen isolated
suppression
resolution
A 37 yofemale with a history of end-stage renal disease, on dialysis, is admitted to the hospital with healthcare-associated pneumonia. Antibiotics are initiated to cover the most likely pathogen(s).
empiric
A 68 yomale presents for a total hip replacement. Prior to surgery, he is given one dose of cefazolin to prevent development of a surgical wound infection
prophylaxis
A 37 yofemale with a history of end-stage renal disease, on dialysis, is admitted to the hospital with healthcare-associated pneumonia. Cultures result with sensitive Pseudomonas, vancomycin is discontinued
definitive
An 8 yomale presents to the ED with a perforated appendix. Antibiotics are initiated pre-operatively to reduce risk of intra-abdominal abscess & wound infection
pre-emptive
A 75 yomale presents to his PCP for follow-up of prosthetic hip joint infection. He receives continued low dose antimicrobial therapy. Hip prosthesis was unable to be removed and replaced during hospitalization.
suppressive
Gram Positive cocci anaerobic
peptococcus
peptostreptococcus
Gram Positive cocci aerobic clusters coagulase positie
staph aureas
Gram Positive coccie aerobic clusters coagulase negative
staph epi staph saprophyticus staph hominis staph hemolyticus staph warneri
Gram Positive cocci aerobic diplococci
streptococcus pneumonia
entrococcus
Gram Positive cocci aerobic chains b hemolytic
strep pyogenes group a
strep agalectiae group b
strep groups cfg
Gram Positive cocci aerobic chains a hemolytic
viridans strep
strep pneumonia
Gram Positive bacilli anaerobic
c diff clostridium perfringens actinomyces lactobacillus
Gram Positive bacilli aerobic
bacillus anthracis
nocardia
listeria
acynebacterium jelkelium
Gram Negative bacilli anaerobic
prevotella
fusobacterium
bacteroides
Gram Negative bacilli aerobic lactose fermenting oxidase positive
aeromonas
pasteurella
vibrio
Gram Negative bacilli aerobic lactose fermenting oxidase negative
ecoli
klebsiella
enterobacter
citrobacter
Gram Negative bacilli aerobic non lactose fermenting oxidase postiive
pseudomonas flavobacterium aitaligenes achromobacter moraxella
Gram Negative bacilli aerobic non lactose fermenting oxidase negative
proteus proficendia serrates morganella slamonella shigella strenotrophomonas acinetobacter
Gram Negative bacilli aerobic misc
brucella bordetella campylobacter pasteurella vibrio
Gram Negative cocci
Neisseria meningitides
neisseriia gonohorrhoaea
vellionella
Gram Negative coccbacilli
h influenza
Moraxella catarrhalis
Susceptible:
Likely to inhibit pathogenic microorganism
Intermediate:
May be effective at higher dosage, more frequent administration, or in specific body site
Resistant:
Not effective at inhibiting growth of microorganism
Minimum inhibitory concentration (MIC):
lowest concentration of drug required to inhibit growth
Breakpoints established by Clinical and Laboratory Standards Institute (CLSI)
Clinical and Laboratory Standards Institute (CLSI) Breakpoints
MIC (μg/mL
Susceptible ≤ 4
Intermediate 8-16
Resistant ≥ 32
Clinical and Laboratory Standards Institute (CLSI) Breakpoints
Zone Diameter (mm)
Susceptible ≥ 20
Intermediate 15-19
Resistant ≤ 14
Zone Diameter (mm)
Act on a single or a limited group of microorganisms
Extended-spectrum
Active against gram-positive bacteria but also against significant number of gram-negative bacteria
Broad-spectrum
Act on a wide variety of bacterial species, including both gram-positive and gram-negative
Bacteriostatic:
arrests growth and replication of bacteria (limits spread of infection)
Bactericidal:
kills bacterial
Concentration-dependent killing: rate and extent of killing increase with increasing drug concentrations
Time-dependent killing: activity continues as long as serum concentration above minimum bactericidal concentration
Bacteriostatic vs. Bactericidal
This concept is relative
Certain drugs are –cidalagainst specific bacteria while –static against others
Drug-drug enhancement or synergism
Gentamicin –ineffective against enterococci in the absence of a cell-wall inhibitor
Combining penicillin with gentamicin leads to bactericidal activity
Antimicrobials classified based on
Class and spectrum of microorganisms it kills
Biochemical pathway it interferes with
Chemical structure
Site of Antibacterial Action
cell wall synthesis
cycloserine vancomycin bacitracin fosfomycin penicillins cephalosporins monbactams carbapenems
Site of Antibacterial Action folic aid metabolism
Bactrim both
paba
Site of Antibacterial Action
cell membrane
polymyxins
Site of Antibacterial Action
dna replication (dna gyrase)
nalidixic acid
quinolones
Site of Antibacterial Action
dna dependent rna polymerase
rifampin
Site of Antibacterial Action
protein synthesis (50 S)
erythromycin
chloramphenicol
clindamycin
Site of Antibacterial Action
protein synthesis (30S)
tetracyclin spectinomycin streptomycin gentamicin tobramycin amikacin
Site of Antibacterial Action
Cell wall synthesis Cell membrane synthesis Protein synthesis Nucleic acid metabolism Function of topoisomerases Folate synthesis
cell wall inihbitors
blactams
penicillins
cephalosporins
1-4th gnereations
carbapenems
monobactams