First Aid- Antimicrobials Flashcards
Penicillin G, V
Prototypical beta lactams
Clinical use: Mostly used for gram positives (s. pneumoniae, s. pyogenes, actinomyces). Also used for gram negative cocci (mainly meningitidis) and spirochetes (mainly T. pallidum). Bactericidal
Mechanism of Resistance: Beta-lactamases, mutations in PBP
Penicillinase-Sensitive Penicillin’s
Amoxicillin, ampicillin, aminopenicillins
Clinical use: Same as penicillin, just broader spectrum. HHEELPSS kill enterococci. (E. pylori, H. influenzae, E. Coli, enterococci, Listeria monocytogenes, proteus mirabilis, salmonella, shigella)
Resistance: Penicillinase, a type of beta lactamase
Penicillin-resistant Penicillin
Dicloxacillin, nafcillin, oxacillin
Mechanism: Same as penicillin, but a narrow spectrum and penicillinase resistant due to large, bulky R group
Clinical Use: Staphylococcus aureus, except MRSA (use naf for staph)
Resistance: MRSA has an altered penicillin-binding site
Antipseudomonal penicillins
Piperacillin (pip-tazo), ticarcillin (ticarcillin-clavulanate)
Mechanism: Same as penicillin, but penicillinase sensitive, so use with beta lactamase inhibitor
Clinical Use: Gram negative coverage, p. aeruginosa, and acinetobacter
1st generation cephalosporins
Cefazolin, cephalexin
Mechanism: Beta lactam drugs that are less susceptible to penicillinases
Clinical Use: Gram positive cocci, proteus mirabilis, e. coli, klebsiella pneumoniae (+PECK).
Cephazolin is used before surgery to prevent s. aureus skin infection
2nd Generation Cephalosporins
Cefaclor, cefoxitine, cefuroxime, cefotetan (2nd Graders wear fake fox fur to tea parties)
Clinical Use: H. influenzae, Enterobacter aerogenes, Neisseria spp, Serratia marcescens, proteus mirabilis, E. Coli, klebsiella (HENS PEcK)
3rd Generation cephalosporins
Ceftriaxone, cefotaxime, cefpodoxime, ceftazidime
Clinical Use: serious gram negative infections infections that are resistant to other beta lactams
Ceftazidime can treat pseudomonas
4th Generation cephalosporins
Cefepime
Clinical use: Gram negative organisms, with increased activity against pseudomonas and gram positive organisms
5th Generation cephalosporins
Ceftaroline
Clinical Use: Broad gram positive and negative coverage; unlike 1st-4th generation cephalosporins, ceftaroline covers MRSA and enterococcus faecalis. Does not cover pseudomonas
Cephalosporin Adverse Effects
Autoimmune hemolytic anemia, disulfiram-like reaction, vitamin K deficiency
Beta-Lactamase Inhibitors
Clavulanic Acid, Avibactam, Sulbactam, Tazobactam (CAST)
Amoxicillin-clavulanate, ceftazidime-avibactam, ampicillin-sulbactam, piperacillin-tazobactam (CAST A CAP)
Carbapenems
Doripenem, Imipenem, Meropenem, Ertapenem
Mechanism: Bactericidal beta-lactams. Broad spectrum, beta lactamase resistant. Always administered with cilastatin to prevent renal inactivation
Clinical Use: Gram positive cocci; gram negative rods and anaerobes. Wide spectrum and significant side effect limit use to life threatening infections (DIME antibiotics are given when there is a 10/10 [life-threatening] infection
Mechanism of resistance: Carbapenemases
Monobactams
Aztreonam
Mechanism of action: Beta lactams
Clinical use: Gram negative rods only. No activity against gram positive rods or anaerobes. Usually non-toxic, so can be used for penicillin-allergic patients and those with renal insufficiency that cannot tolerate aminoglycosides
Vancomycin
Inhibits cell wall peptidoglycan formation by binding to the D-Ala-D-Ala portion of the cell wall precursors
Clinical use: Gram positive bugs only. For serious, multidrug resistant organisms, such as MRSA, s. epidermidis, some enterococcus species, and c. diff
Adverse Effects: They are NOT trouble Free (Nephrotoxicity, Ototoxicity, Thrombophlebitis (inflammatory process that causes blood clot), diffuse flushing (red-man syndrome)
Mechanism of Resistance: Changes an alanine to lactate
What are the different protein synthesis inhibitors?
30s Inhibitors
- Aminoglycosides
- Tetracyclines
- Tigecycline
50s Inhibitors
- Chloramphenicol
- Clindamycin
- Macrolides
- Linezolid
Buy ATT 30, CCEL (macrolides, the e is for erythromycin) at 50
All bacteriostatic, except aminoglycosides (bactericidal) and linezolid (variable)
Aminoglycosides
Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin (Mean [amino acids] GNATS caNNOT kill anaerobes
Clinical Use: Severe gram - rod infections. Synerginistic with beta lactams. Neomycin is used in bowel surgeries
Mechanism: Bactericidal; irreversibly bind the 30s subunit
Adverse Effects: Nephrotoxicity, Neuromuscular blockade, Ototoxicity, Teratogenicity
Tetracyclines
Tetracycline, doxycycline, minocycline
Clinical Use: Mycoplasma pneumoniae, borrelia burgdorferi. Chlamydia and Rickettsia, due to it’s ability to accumulate intracellularly. Community acquired MRSA
Tigecycline
Clinical use: Broad gram negative and positive coverage. MRSA, VRA and other multi-drug resistant organisms. Infections that require deep tissue penetration
Chloramphenicol
Clinical Use: Meningitis (caused by haemophilus influenzae, neisseria meningitidis, streptococcus pneumoniae) and rickettsial diseases (e.g., Rocky Mountain spotted fever)
Adverse Effects: Anemia
Mechanism of Resistance: Plasmid-encoded acetyltransferase inactivates the drug
Clindamycin
Clinical Use: Anaerobic infections (ex: Bacteroides spp, clostridium pefringes) in aspiration pneumonia, lung abscess, oral infections. Also effective against invasive group A streptococcal infection
Adverse effects: C. diff, fever, diarrhea
Note: It treats anaerobic infections above the diaphragm, while metronidazole treats anaerobic infections below the diaphragm.
Linezolid
Clinical Use: Gram positive species, including MRSA and VRE
Adverse effects: serotonin syndrome, peripheral neuropathy, bone marrow suppression
Macrolides
Azithromycin, clarithromycin, erythromycin
Clinical Use: Atypical pneumonias (mycoplasma, chlamydia, legionella), STI (chlamydia), gram positive cocci (streptococcal infections in patients allergic to penicillin)
Adverse Effects: MACRO (Motility issues, arrhythmia, cholestatic hepatitis, rash, eOsinophilia)
Polymixins
Colistin (Polymixin E), polymyxin B
Mechanism: Cation polypeptides bind to the phospholipids on the cell membrane of gram negative bacteria, disrupting the membrane
Clinical Use: Salvage therapy for multi-drug resistant gran negative bacteria (P. aeruginosa, e. coli, k. pneumoniae). Part of neosporin/topical triple antibiotic treatments
Adverse Effects: Nephrotoxicity, neurotoxicity
Antimycobacterial therapy
M. tuberculosis–> Rifampin, Isoniazid, pyrazinamide, ethambutol (RIPE for treatment)
Rifamycins
Rifampin, rifabutin
Mechanism of action: Inhibits DNA dependent RNA polymerase
Clinical Use: Mycobacterium tuberculosis;
Adverse effects: Minor hepatotoxicity
Isoniazid
Mechanism of Action: Inhibits synthesis of mycolic acid, part of the cell wall of mycobacteria
Clinical Use: Both a m. tuberculosis prophylactic and treatment
Adverse effects: INH- Injures Neurons and Hepatocytes.
Pyrazinamide
Mechanism: unknown
Clinical Use: M. tuberculosis
Ethambutol
Mechanism: Inhibits the carbohydrate polymerization of mycobacterium by blocking arabinotransferase
Clinical Use: Mycobacterium tuberculosis
Streptomycin
Mechanism: Aminoglycoside, inhibiting the 30s subunit
Clinical Use: m. tuberculosis
Sulfonamides
Sulfamethoxazole (SMX), sulfisoxazole, sulfadiazine
Mechanism: Inhibits folate synthesis. Bacteriostatic, but bactericidal when combined with trimethoprim
Clinical Use: Gram positive, gram negative, nocardia. SMX-TMP for simple UTI
Trimethoprim
Inhibits dihydrofolate reductase. Bacteriostatic
Clinical Use: Used with sulfamethoxazole to cause sequential block of folate synthesis. This combination is used for UTI’s, shigella and salmonella
Fluoroquinolones
Ciprofloxacin, enoxacin, norfloxacin, ofloxacin;
Respiratory fluoroquinolones: Gemifloxacin, levofloxacin, moxifloxacin
Mechanism: Inhibits DNA gyrase and topoisomerase IV. Bactericidal
Clinical Use: Gram negative rods of urinary and GI tract (including pseudomonas). Must not be taken with antacids
Daptomycin
Mechanism: Lipopeptide that disrupts cell membranes of gram positive cocci by creating transmembrane channels
Clinical Use: S. aureus skin infections (especially MRSA), bacteremia, endocarditis, VRE. NOT used for pneumonia. Daptomyskin is used for skin infections
Metronidazole
Mechanism: Forms toxic free radicals in bacterial cells that damage the DNA
Clinical Use: Giardia, entamoeba, trichomonas, gardnerella vaginalis, anaerobes (Bacteroides, c.difficle) Can be used to treat h. pylori instead of amoxicillin in case of penicillin allergy. GET GAP
