Antibiotics Flashcards
What classes of antibiotics inhibit the cell wall?
Inhibitors of Cell Wall Synthesis - peptidoglycan is the key target
- Beta-lactams: penicillins, cephalosporins, carbapenems/monobactams
- Glycopeptides
- Phosphonic acid
What is the spectrum of activity of penicillins?
Penicillin
- Narrow activity against gram + organisms
- Group A Streptococcus
- Streptococcus pneumonia
What is the spectrum of activity of aminopenicillins ex. ampicillin, amoxicillin?
Aminopenicillins
- Increased gram + activity
- S. pneumoniae
- Enterococcus
- Some gram - activity
What is the MOA of cloxacillin?
Cloxacillin is a penicillin therefore it inhibits the formation of the cell wall. It has potent activity against methicillin-susceptibel S. aureus (MSSA).
What is the MOA of glycopeptides?
Inhibits cell wall
What is the MOA of phosphonic acids?
Inhibits cell wall
What is the MOA of aminoglycosides, macrolides, lincosamides, tetracyclines and oxazolidinone?
Inhibit protein synthesis
What is the MOA of fluoroquinolones, rifamycins, trimethoprims, nitroimidazoles?
Disruption of DNA & NA synthesis
What is the mechanism of action of lipopeptide and polymixin?
Disruption of cell membrane
What is the MOA of nitrofurantoin ex. macrobid?
Disruption of metabolism/respiration
Penicillin
MOA
Coverage
Organisms
Penicillin
MOA: inhibits cell wall
Coverage: narrow activity against G+ organisms
Organisms: Group A streptococcus, S. pneumonia
Ampicillin, Amoxicillin
MOA
Coverage
Organisms
Ampicillin, Amoxicillin
MOA: inhibits cell wall
Coverage: increased G+ activity, some G- activity
Organisms: Streptococcus pneumonia, Enterococcus
Cloxacillin
MOA
Coverage
Organisms
Cloxacillin
MOA: inhibits cell wall
Coverage: G+
Organism: potent activity against methicillin-susceptible S. aureus (MSSA)
Pip/Tazo
MOA
Coverage
Organisms
Piperacillin-Tazobactam
MOA: inhibits cell wall
Coverage: broad spectrum! Activity against G+, G- and anerobes
Organisms: activity against pseudomonas, enterococcus
1st Gen. Cephalosporins (cefazolin, cephalexin, cefadroxil)
MOA
Coverage
Organisms
1st Gen. Cephalosporins (cefazolin, cephalexin, cefadroxil)
MOA: inhibit cell wall
Coverage: activity against G+ (limited activity against susceptible G-)
Organisms: MSSA, streptococci
*No activity against MRSA, enterococcus
2nd Gen. Cephalosporins (cefuroxime, cefoxitin, cefprozil)
MOA
Coverage
Organisms
2nd Gen. Cephalosporins
MOA: cell wall inhibitor
Coverage: G+, G-; increased activity against G- respiratory pathogens
Organisms: Haemophilus influenzae, Moraxella
- Cefoxitin has activity against anaerobes
- No activity against MRSA, enterococcus
3rd Gen. Cephalosporins (ceftriaxone, cefotaxime, ceftazidime, cefixime)
MOA
Coverage
Organisms
3rd Gen. Cephalosporins
MOA: cell wall inhibitor
Coverage: G+, increased activity against G- with CNS penetration
Organism: Neisseria meningitidis
- Ceftazidime has activity against Pseudomonas but decreased G+ activity
- Cefixme has limited G+ activity
- No activity against MRSA, enterococcus
4th Gen. Cephalosporins (Cefepime)
MOA
Coverage
Organisms
Cefepime
MOA: cell wall inhibitor
Coverage: G+, G-
Organisms: Pseudomnoas aeruginosa
- Activity against MRSA and enterococcus
- As you move up in generations of cephalosporins you have increased G- activity but the G+ activity becomes less
Carbapenem (meropenem, ertapenem)
MOA
Coverage
Organisms
Carbapenems (meropenem, ertapenem)
MOA: cell wall inhibitor
Coverage: broad spectrum including aerobes and anaerobes
Organisms: resistant G- including Pseudomonas, Acinetobacter
- Ertapenems ahs no activity against Pseudomonas
- Variable activity against Enterococcus
Glycopeptides (Vancomycin, Teicoplanin)
MOA
Coverage
Organisms
Glycopeptides (Vancomycin)
MOA: cell wall inhibitor
Coverage: G+
Organisms: Resistant staphylococci, MRSA, resistant S. pneumoniae, Enterococcus, po formulation aginst C. diff only
Monobactams (Aztreonam)
MOA
Coverage
Organisms
Monobactams (aztreonam)
MOA: cell wall inhibitor
Coverage: G-
Organisms: Pseudomonas aeruginosa
Clindamycin
MOA
Coverage
Organisms
Clindamycin (Lincosamide)
MOA: protein synthesis inhibitor
Coverage: activity against G+ and anaerobes
Organisms: Viridans Streptococcus, Streptococcus pneumoniae
- Activity against some MRSA strains
Aminoglycosides (Gentamicin, tobramycin)
MOA
Coverage
Organisms
Aminoglycosides (gentamicin, tobramycin)
MOA: protein synthesis inhibitor
Coverage: Activity against G- including Pseudomonas, no activity against anaerobes
Organisms: Pseudomonas aeruginosa
Tetracyclines (Tetracyclin, minoclycline, doxycycline)
MOA
Coverage
Organisms
Tetracyclines (Tetracyclin, minoclycline, doxycycline)
MOA: protein synthesis inhibitor
Coverage: G+ and G- including RT pathogens, atypicals, ricketsial infections, malaria, activity against some MRSA strains
Organisms: Chlamlydia
Macrolides (Erythromycin, Clarithromycin, Azithromycin)
MOA
Coverage
Organisms
Macrolides (Erythromycin, Clarithromycin, Azithromycin)
MOA: protein synthesis inhibitor
Coverage: G+ and some G-
- Activity against S. pneumoniae, RT pathogens and atypicals (mycoplasma, chlamydia, Legionella)
- Activity against Group A streptococcus, MSSAm (increase resistance)
- Activity against some GI pathogens
- Activity against some non-tuberculous mycobacteria
Fluoroquinolones (Ciprofloxacin, Levofloxacinm Moxifloxacin)
MOA
Coverage
Organisms
Fluoroquinolones (Ciprofloxacin, Levofloxacinm Moxifloxacin)
MOA: DNA synthesis inhibitor
Coverage: G+, G-, activity against atypicals
Organisms: Cipro has activity against Pseudomonas but limited against S. pneumoniae
Nitroimidazoles (Metronidazole)
MOA
Coverage
Organisms
Nitroimidazoles (Metronidazole)
MOA: DNA synthesis inhibitor
Coverage: potent activity against anaerobes, G+, G-
Organisms: activity against C. diff, activity agianst intestinal protozoa including Entamoeba, Giardia
What bugs are commonly associated with the skin?
Skin
G+
- Staphylococcus aureus (part of normal flora)
- Coagulase negative Staph (S. Epidermis) (part of normal flora)
- Group A Streptococccus (S. Pyogenes)
- Group C and G Streptococccus
- Viridans Strep (part of normal flora)
- Corynebacterium (part of normal flora)
G-
- Pseudomonas aeruginosa
What bugs are commonly associated with the GI tract?
GI Bugs
G+
- Viridans streptococcus (part of normal flora)
- Enterococcus (part of normal flora)
- Peptostreptococcus and Finegoldia
- Lactobacillus (part of normal flora)
- Clostridium difficile
- Clostridium perfringens
G-
- Vibrio cholerae
- Helicobacter pylori
- Campylobacter
- Veionella (part of normal flora)
- Enterobacteriaceae
- Bacteroides Fragilis (part of normal flora)
What are some bugs associated with the respiratory tract?
Respiratory Tract
G+
- Strep. pneumo.
G-
- Neisseria meningitidis
- Legionella
Yeast-Like Fungus: Pneumocystis jirovecii pneumonia
Mold: Aspergillus
