5 - Antimicrobials Flashcards
Antimicrobial coverage of extended spectrum penicillins
- Amox
- Ampi
Amoxicillin HELPS kill Enterococci
- Haemophilus influenzae
- E. coli
- Listeria monocytogenes
- Proteus mirabilis
- Salmonella sp
- Enterococci
BacteriCIDAL
Very Finely Proficient At Murder
- vancomycin
- flouroquinolones
- penicillins
- aminoglycosides
- metronidazole
BacterioSTATIC
we’re ECSTaTiC about bacteriostatics
- erythromycin
- clindamycin
- sulfamethoxazole
- trimethoprim
- tetracycline
- chlorampenicol
Antipseudomonal Penicillins
TCP: Take Care of Pseudomonas
- ticarcillin
- carbenicillin
- piperacillin
First generation cephalosporins cover which microbes
PEcK 1st
- proteus mirabilis
- E. coli
- Klebsiella pneumoniae
First gen cephalosporins
FADer, help me FAZ my PHarmacology boards!
- cefadroxil
- cefazolin
- cephalothin
- cephapirin
- cephradine
- cephalexin
Second generation cephalosporins cover which microbes
HEN PEcKS
- Haemophilus influenzae
- Enterobacter aerogenes
- Neisseria spp.
- Proteus mirabilis
- E. coli
- Klebsiella pneumoniae
- Serratia marcescens
Second generation cephalosporins
in a FAMily gathering, you see your FOXy cousin wearing a FUR coat and drinking TEA.
- ceFAMandole
- ceFOXitin
- ceFURoxime
- cefoTEtan
FAC! LORA the PROfessional AZhOLE is still on the FONe.
- ceFAClor
- LORAcarbef
- cefPROzil
- cefmetAZOLE
- ceFONicid
DOC for gonorrhea
Ceftriaxone and Cefixime
3rd gen cephalosporins with anti-pseudomonal activity
Pag may pseudomonas, kailangan ma-ICU
- need ng PERA (cefoPERAzone)
- sosyal ka, ayaw ng pera pero gusto ng DIME (ceftaziDIME)
- kailangan malakas like TRIathlete (cefTRIaxone) - case to case basis
- cefoperazone
- ceftazidime
- ceftriaxone
DOC for syphilis
Penicillin
- binds to PBP
- inhibits transpeptidation in bacterial cell walls
- narrow spectrum
Anti-pseudomonal cephalosporins
- ceftazidime
- cefoperazone
- cefepime
Commonly used against Bacteriodes
Ceftizoxime
- 3rd gen
Most active 3rd gen cephalosporins against Penicillin-resistant S. pneumoniae
- ceftriaxone
- cefotaxime
Cell wall inhibitors RESISTANT to beta-lactamase (penicillinase)
- methicillin
- 4th gen cephalosporins (ceftaroline, cefpirome)
Beta-lactam antibiotic reserved for serious life-threatening infections such as pneumonia and sepsis
Carbapenem
- imipenem-cilastatin
- ertapenem
- meropenem
- doripenem
-has wide coverage
It inhibits renal metabolism (hydrolysis) of imipenem by dihydropeptidase
Cilastatin
All carbapenems are active against Pseudomonas and Acinetobacted EXCEPT __________
Ertapenem
Given with imipenem which will act as dihydropeptidase inhibitor
Cilastatin
Cilastatin is added to what carbapenem
Imipenem
Carbapenem which has longer half-life but less active against Enterococci and Pseudomonas
Ertapenem
All 3rd gen cephalosporins are renally excreted EXCEPT ___________
- cefoperazone
- ceftriaxone
All 3rd gen cephalosporins penetrate BBB EXCEPT ____________
- cefoperazone
- cefixime
3rd gen cephalosporin that has very good CNS penetration
Ceftriaxone
3rd gen cephalosporins should be reserved against serious infection EXCEPT ______________
- ceftriaxone
- cefixime
It is used for infections resistant to beta-lactamases produced by G (-) rods
- silver bullet
Aztreonam
- monobactam
Beta-lactamase inhibitors
CST
- clavulanic acid (amox)
- sulbactam (ampi)
- tazobactam (piperacillin)
Plasmid encoded B-lactamases organisms
GESH
- gonorrhea
- E. coli
- streptococci
- H. influenzae
Inducible chromosomal B-lactamases organisms
PES
- pseudomonas
- enterobacter
- serratia
4th gen cephalosporin for MRSA
Ceftaroline
- bactericidal
Inhibits cell wall synthesis by binding to D-Ala-D-Ala terminus which will inhibit transglycosylation eventually preventing elongation and cross-linking of peptidoglycan chain
Glycopeptide
Vancomycin
- Teicoplanin
- Dalbavancin
- Telavancin
A/E: Red Man Syndrome
Vancomycin
- treated by slowing rate of infusion
What formulation of vancomycin (glycopeptide) is used for pseudomembranous colitis
Oral
VRSA and VRE are due to _________
D-Ala-D-Lactate formation
These glycopeptides are not absorbed in the GIT thus used for bacterial enterocolitis
TT
- teicoplanin
- telavancin
Glycopeptide that has very long half-life (6-11 days) which permits 1/week dosing and is more active than Vancomycin
Dalbavancin
Drugs of Last Resort
I AM your Last Shot at Victory
- imipinem
- amikacin
- meropenem
- linezolix
- streptogramins
- vacomycin
Peptide antibiotic which interferes with a late stage in cell wall synthesis in G(+)
Bacitracin
- NEPHROTOXIC!!!
- topical ONLY
Used for drug-resistant TB (2nd line) which blocks INCORPORATION of D-Ala into the pentapeptide side chain of the peptidoglycan
Cycloserine
- neurotoxic
It binds to cell membrane causing DEPOLARIZATION and RAPID CELL DEATH
Rapidly inactivated by pulmonary surfactants
Daptomycin
- G(+) including sepsis and endocarditis
- A/E: myopathy - requires creatine phospholinase monitoring
- inactivates by pulmonary surfactants
Inactivates UDP-N-acetylglucosamine-3-enolpyruvyltransferase which is important in peptidoglycan synthesis
Fosfomycin
Protein synthesis inhibitors
AT (30s) CELLS (50s)
- aminoglycosides
- tetracycline
- Chloramphenicol
- erythromycin (macrolides)
- lincosamides (clindamycin)
- linezolid
- Streptogramins
All protein synthesis inhibitors are bacterioSTATIC except ___________ to the following bugs:
- haemophilus
- neisseria
- bacteroides
- s. pneumoniae
- aminoglycosides
- streptogramins
- chloramphenicol
All protein synthesis inhibitors are bacterioSTATIC EXCEPT: - aminoglycosides - streptogramins - chloramphenicol to the following bugs \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
- haemophilus
- neisseria
- bacteroides
- s. pneumoniae
Drug that this bacteriostatic BUT CIDAL to:
- haemophilus
- neisseria
- bacteroides
- s. pneumoniae
Chloramphenicol
Chloramphenicol is bacteriostatic but CIDAL to what bugs:
- haemophilus
- neisseria
- bacteroides
- s. pneumoniae
Gray baby syndrome
Chloramphenicol
Administration of Chloramphenicol will cause this condition that is characterized by:
- decreased RBCs
- cyanosis
- CV collapse
- ashen gray skin
Gray Baby Syndrome
Premature neonates are deficient in hepatic glucuronosyl transferase
- glucuronidation of chloramphenicol
Causes tooth enamel dysplasia/discoloration
TEETHracycline
Tetracycline
Block aTTachment of T-RNA to acceptor site
Broadest spectrum and longest half life tetracycline
Tigecycline (30-36 hours)
All tetracyclines are excreted renally EXCEPT
Doxycycle
- bile
Tetracycline that is given only through IV and is unaffected by common tetracycline resistance mechanisms
Tigecycline
Macrolide uses:
- erythromycin
- azithromycin
- clarithromycin
- telithromycin
- roxithromycin
- CAP
- pertussis
- diphtheria
- chlamydia
Macrolide that may cause rare fulminant hepatic failure
Telithromycin
All macrolides inhibit CYP450 except
Azithromycin
Macrolide that has the high distribution of volume and longest half-life
Azithromycin
Macrolide used for macrolide-resistance
Telithromycin
- may cause rare fulminant hepatic failure
Resistance of macrolide is due to:
- Development of efflux pumps
- Production of methylase enzyme
Resistance of chloramphenicol is due to:
Formation of acetyltransferase that inactivates drug
Resistance of tetracycline is due to:
- Development of efflux pumps for active extrusion of tetracyclines
- formation of ribosomal protection proteins that interfere with tetracycline binding
Lincosamide drugs
- clindamycin
- lincomycin
A/E: pseudomembranous colitis (C. difficile overgrowth)
For PCP pneumonia
G(-) aerobes are resistant because of poor penetration through outer membrane
Linsamide resistance is due to:
- methylation of binding siyes and enzymatic inactivation
Anaerobic infections ABOVE the diaphragm
Clindamycin
Anaerobic infections BELOW the diaphragm
Metronidazole
Used for drug-resistant G(+) cocci such as Staphylococci and E. faecium (MRSA, VRSA, VRE)
- inhibits CYP450 (multiple drug reactions)
- A/E: injection site reactions, severe arthralgia/myalgia syndrome
Streptogramin
- cidal
Quinipristin-Dalfopristine
Used for drug-resistant G(+) cocci such as Staphylococci and E. faecium (MRSA, VRSA, VRE) + Corynebacteria, Listeria
A/E: serotonin syndrom (with ssri), optic neuritis, BM suppression
Oxazolidinone
- Linezolid
- Tedizolid
Binds to 23s subunit of 50s
Oxazolidinone (linezolid) resistance is due to:
Decreased affinity of drug to binding site
Macrolides mneomic
CRATE
- clarithromycin
- Roxithromycin
- Azithromycin
- Telithromycin
- Erythromycin
Class of antibiotic that has POST-ANTIBIOTIC EFFECT
Aminoglycosides
- killing continues when their plasma levels have declined below measurable levels
PROTOCOL BASIS:
- shorter with single large dose than multiple small doses
Quinolones
- interfere with bacterial DNA synthesis
How is aminoglycoside bacteriCIDAL?
- because of misreading
- it occupies a large space in P site that will cause misreading
- concept of STOP CODON
Aminoglycoside that has the NARROWEST therapeutic window
Amikacin
Aminoglycosides in general:
- not absorbed if oral
- better: IM/IV
- not readily cross BBB
- excretion: Glomerular filtration
Class of antimicrobial that has synergistic effect with cell wall inhibitors (enhancement of transport)
Aminoglycosides
GNATS NOT
- gentamicin
- neomycin
- amikacin
- Tobramycin
- Streptomycin
- Nephrotoxic
- Ototoxix
- Teratogen
MOA of aminoglycosides
Bind to 30S:
- block formation of initiation complex
- cause misreading of the code (mRNA template)
- inhibit translocation
Resistance to aminoglycosides
- plasmid-mediated formation of inactivating enzymes (group transferases)
Amikacin - often resistant
Streptomycin resistance - changes to ribosomal binding site
Streptomycin resistance is due to:
Changes in the ribosomal binding site
Aminoglycoside that is often resistant to many enzymes that inactivate orher aminoglycosides
Amikacin
- has the narrowest therapeutic window
Aminoglycosides need ______ for uptake
Oxygen (O2)
- DOES NOT work on ANAEROBIC conditions
Aminoglycoside drugs
GNATS
- gentamicin
- neomycin
- amikacin
- tobramycin
- streptomycin
Most vestibulotoxic and nephrotoxic aminoglycosides
- gentamicin
- tobramycin
Cumulative ototoxicity with loop diuretics
Aminoglycoside used in multi drug-resistant TB (2nd line)
Amikacin
- least resistance
- narrowest therapeutic window
Cycloserine
- Cell wall inhibitor used for drug-resistant TB (2nd line)
- blocks incorporation of D-ala into the pentapeptide
- neurotoxic
Aminoglycoside that causes congenital deafness
Streptomycin
Aminoglycoside used to TB, tularemia, bubonic plague, brucellosis, enterococcal endocarditis
Streptomycin
- has widespread resistance due to changes in the ribosomal binding site
- given with Pens: for enterococcal endocarditis, TB plague, tularemia
Most ototoxic aminoglycoside
Kanamycin and amikacin
Aminoglycoside that is limited to topical and oral use
Neomycin
Reverse neuromuscular blockade of aminoglycosides (Neomycin/Kanamycin/Paromomycin)
Calcium gluconate and neostigmine
Aminoglycoside used for visceral leishmaniasis
Paromomycin
Aminoglycoside used for drug-resistant gonorrhea and gonorrhea in penicillin-allergic patients
Spectinomycin
- no cross resistance with other gonorrheal drugs
- IM
Aminoglycoside that has anemia as side effect
Spectinomycin
Aminoglycosides that causes skin reactions
Neomycin and streptomycin
Protein synthesis inhibitor - inhibits translocation process during protein synthesis
Fusidic acid or Na Fusidate
- isolated from fermentation of Fusidium coccineum
- topical for skin pathogens including S. aureus
Isolated from fermentation of Fusidium coccineum
Fusidic acid or Na Fusidate
- inhibits translocation process during protein synthesis
- topical for skin pathogens including S. aureus
Antifolate drugs that is weakly acid that have a common chemical nucleus resembling p-aminobenzoic acid (PABA)
Sulfonamides
Antifolate drug that is weakly basic
Trimethoprim
- reaches high concentrations in prostatoc and vaginal fluids
Competitive inhibitor of dihydropteroate SYNTHASE
Sulfonamides
- bacteriostatic
- selective toxicity results from the inability of mammalian cells to syntesize folic acid
- compete with PABA
Selective inhibitor of dihydrofolate REDUCTASE
Trimethoprim
- bacteriostatic
Resistance to antifolate drugs
Plasmid-mediated and results from:
- decreased intracellar accumulation of the drugs
- increased production of PABA by bacteria
- decrease in sensitivity of dihydropteroate synthase to sulfonamides
Antifolate drug that inhibit dihyrdopteroate synthase for burn infections
Silver sulfadiazine / Mafenide acetate
Antifolate drug that can cause metabolic acidosis and penetrate eschar
Mafenide acetate
Sulfonamide that is only for lower UTI
Sulfisoxazole
DOC for toxoplasmosis
Sulfadiazine-Pyrimethamine
Antifolate drug 2nd line agent for Malaria
Sulfadoxine-Pyrimethamine
Antifolate drug that is used for lower UTI and may be safely given to patients with sulfonamide allergy
Trimethoprim
Antifolate drugs that is co-administered with Leucovorin to limit bone marrow toxicity
Pyrimethamine
Class of antibiotics that displace bilirubin binding sites leading to kernicterus
Sulfonamides
Toxicities of sulfonamides
- hypersensitivity
- gastrointestinal distress
- hematotoxicity
- nephrotoxicity
- drug interactions
Class of antibiotics that displace protein binding affecting levels of warfarin and methotrexate
Sulfonamides
Drug interactions seen in sulfonamides
- displace protein binding affecting levels of warfarin and methotrexate
- displace bilirubin binding sites leading to kernicterus
What class of antibiotics will you see greater coverage for G(+) organisms as you increase the generation?
Quinolones
Cephalosporins
- increase generation, increase G(-) activity
MOA of Quinolones
Interfere with DNA synthesis by inhibiting:
- Topoisomerase II (DNA Gyrase) - G(-) which prevents relaxation of supercoiled DNA
- Topoisomerase IV - G(+) which interferes with the separation of replicated chromosomal DNA during cell division
Class of antibiotic that may damage growing cartilage and cause arthropathy
Quinolones
Resistance to Fluoroquinolones
- decreased intracellular accumulation of the drug via production of efflux pumps
- changes in porun structure
- changes in the sensitivity of the target enzymes via point mutations in the antibiotic binding regions
Quinolone that is 2nd line drug to TB
Ciprofloxacin and others
- 2nd gen quinolones
Levofloxacin and others
- 3rd gen
Other:
- norfloxacin
- ofloxacin
- lemofloxacin
- enoxacin
2nd line TB drugs
- cycloserine (blocks incorporation of D-ala into the pentapeptide) - drug-resistant TB
- streptomycin (aminoglycoside) - multi drug-resistant TB
Class of antibiotics that enhance the toxicity of methylxanthine (theophylline)
Quinolones
Quinolone that is most active against G(-) esp Pseudomonas
Ciprofloxacin
General properties of Quinolones:
- good oral bioavailability
- high volume of distribution
- half-life: 3-8 hours
- absorption impeded by antacids
- elimination bia kidneys by tubular secretion (may compete with probenecid)
EXCEPT
Moxifloxacin
- 3rd gen quinolone
- NEVER USE for UTI
- hepatic elimination
Quinolone withdrawn due to severe cardiotoxicity (arrhythmias)
Grepafloxacin
Quinolone withdrawn due to DM (cause hyperglycemia)
Gatifloxacin
Quinolone that can be used against C. trachomatis
Ofloxacin
- 2nd gen
Quinolone that can be used in CAP caused by:
- Chlamydia
- Legionella
- Mycoplasma
Levofloxacin
- has superior activity against G(+) including S. pneumoniae
Newest members of Quinolones that are considered to have the BROADEST SPECTRUM of activity with increased activity against anaerobes anf atypical agents
Moxifloxacin and Gemifloxacin
Quinolones that can cause QT prolongation
- gemifloxacin
- levofloxacin
- moxifloxacin
Quinolones that has the WIDEST spectrum of activity
- enhanced activity against anaerobes
4th gen quinolones
- trovafloxacin (hepatotoxic)
- alatrofloxacin
- prulifloxacin
- clinafloxacin
MOA of Metronidazole (Nitroimidazole, Antiprotozoal)
Reactive reduction by ferredoxin forming free radicals that distupt electron transport chain
- A/E: metallic taste; Disulfiram reaction
Clara took the Pre-Med Test in the PM
- chlorpropamide
- cefoPerazone
- cefaMandole
- cefoTetan
- Procarbazine
- Metronidazole
DOC for ameobiasis, giardiasis and pseudomembranous colitis
Metronidazole