Beta-lactams Flashcards
Mechanism of action of beta-lactams
Inhibition of bacterial cell wall synthesis. Bind and inactivate penicillin binding proteins. Prevents cross-linking and activates bacterial cell’s autolytic system leads to cell death.
The following 3 classes of antibiotics are beta-lactams
- Penicillins
- Cephalosporins
- Carbapenems
What do bacteria produce to counter beta-lactams?
Beta-lactamases
Clavulanic acid and tazobactam are 2 examples of what?
Beta-lactamase inhibitors
The penicillins include: (7)
- Penicillin V (PO)
- Penicillin G (IV)
- Amoxicillin (PO)
- Ampicillin (IV)
- Cloxacillin (PO/IV)
- Piperacillin (IV)
- Ticarcillin (IV)
Spectrum and indications for Penicillin V (PO) and Penicillin G (IV)
- Streptococci
2. Bacterial pharyngitis and endocarditis (IV)
Spectrum and indications for Amoxicillin (PO) and Ampicillin (IV)
- Streptococci and Enterococcus faecalis
2. Otitis media, community acquired pneumonia (CAP), enterococcal infections
Spectrum and indications for Cloxacillin PO/IV
- MSSA
- IV = bacteremia, endocarditis, bone/joint infections
- PO = STTI
Spectrum and indications for Amoxicillin/clavulanate PO
Spectrum = Gram +ve, Gram -ve, and anaerobes
Indications = polymicrobial infections (bite wounds, diabetic foot ulcer)
Spectrum and indications for Piperacillin/tazobactam IV
Spectrum: Gram +ve, Gram -ve, Pseudomonas aeruginosa, anaerobes
Indications: Febrile neutropenia, intraabdominal, polymicrobial infections, sepsis unknown source
Spectrum and indications for Ticarcillin/clavulanate IV
Spectrum: Gram +ve, Gram -ve, Pseudomonas aeruginosa, anaerobes
Indications: Febrile neutropenia, intraabdominal, polymicrobial infections, sepsis unknown source
The following drugs are considered Cephalosporins (10)
- Cephalexin PO (1st)
- Cefazolin IV (1st)
- Cefuroxime IV (2nd)
- Cefuroxime axetil PO (2nd)
- Cefprozil PO (2nd)
- Cefotaxime (3rd)
- Ceftriaxone IV (3rd)
- Cefixime PO (3rd)
- Ceftazidime IV (3rd)
- Cefepime IV (4th)
Spectrum and indications for Cephalexin PO (1st)
Spectrum: S. aureus (MSSA) and beta hemolytic Streptococci
Indications: SSTI
Spectrum and indications for Cefazolin IV (1st)
Spectrum: MSSA, Streptococci, E. coli, Proteus mirabilis, Klebsiella
Indications: SSTI, bone/joint, surgical prophylaxis
Spectrum and indications for Cefuroxime IV, Cefuroxime axetil PO, and Cefprozil PO (2nd)
Spectrum: S. pneumoniae (if penicillin susceptible), H. influenzae, M. cattarrhalis
Indications: CA respiratory infections (NOT first line)
Spectrum and indications for Cefotaxime and Ceftriaxone IV (3rd)
Spectrum: Streptococci, penicillin I/R S. pneumoniae, Gram -ve
Indications: Urosepsis, endocarditis, SSTI, meningitis
Spectrum and indications for Cefixime PO (3rd)
Spectrum: Streptococci (if penicillin susceptible), Gram -ve
Indications: UTI, gonorrhea
Spectrum and indications for Ceftazidime IV (3rd)
Spectrum: Pseudomonas aeruginosa
Indications: Combined with aminoglycosides for severe Pseudomonas infections
Spectrum and indications for Cefepime IV (4th)
Spectrum: Gram +ve, penicillin I/R S. pneumoniae, MSSA, Gram -ve, Pseudomonas aeruginosa
Indications: Combined with aminoglycosides for Pseudomonas infections, febrile neutropenia, polymicrobial infections
Cephalosporins in general have no activity against the following: (2)
- Enterococci
2. MRSA
The following are considered Carbapenems (3)
- Ertapenem IV
- Meropenem IV
- Imipenem IV
Spectrum and indications for Ertapenem IV
Spectrum: Gram +ve, Gram -ve, Extended Spectrum Beta-Lactamase (ESBL)/AmpC producers, anaerobes
Indications: Outpatient Rx of polymicrobial infections or multidrug resistant organisms
Spectrum and indications for Meropenem IV
Spectrum: Gram +ve, Gram -ve, ESBL/AmpC producers, Pseudomonas, anaerobes
Indications: Post-trauma or neurosurgical meningitis, polymicrobial infections (with suspected multidrug resistant organisms)
Spectrum and indications for Imipenem IV
Spectrum: Gram +ve, Enterococcus faecalis, Gram -ve, ESBL/AmpC producers, Pseudomonas, anaerobes
Indications: Intraabdominal, polymicrobial infections (with suspected multidrug resistant organisms)
Carbapenems are first line for community acquired infections, True or False?
FALSE.
Carbapenems are reserved for serious infections with known/suspected colonization/infection with multidrug resistant pathogens, True or False?
TRUE
Carbapenems have NO activity against what?
MRSA