Week 2 - Antibiotics Flashcards
What factors contribute to antimicrobial resistance?
4 factors
- Increasing number of immunocompromised pts
- Number of invasive procedures
- Usage of antimicrobials
- Survival of pts with chronic diseases
Leading risk factors for having a drug resistant pathogen
4 factors
- Recent antimicrobial use
- Multiple comorbidities
- Recent hospitalization
- Immunosuppresion
Inappropriate use of antimicrobials
3 examples
- Use for viral etiologies
- Excessive duration of therapy
- Empirical use when not indicated
Define
Antimicrobial
All drugs with ability to kill or inhibit microbes
Define
Antibiotic
Antimicrobials that target bacteria
Define
Bactericidial
99.9% Eradication of a bacterial colony in 24 hours
Define
Bacteriostatic
Kills bacteria but less than 99.9% eradication in 24 hours
4 Types of beta-lactam antibiotics
- Penicillins
- Cephalosporins
- Carbapenems
- Monobactams
MOA of Beta-Lactams
Inhibit the biosynthesis of the bacterial cell wall by binding to PBPs (Penicillin binding proteins) stopping the formation of the peptidoglycan structure
Types of Natural Penicllins
4 types
- Penicillin V
- Procaine Penicillin
- Benzathine Penicillin
- Penicillin G
Types of Aminopenicillins
2 types
- Amoxicillin
- Ampicillin
Antistaphyloccoccal Penicillins
3 Types
- Nafcillin
- Oxacillin
- Dicloxacillin
How is resistance mediated by staphylococci?
Gene and Action
mecA Gene encodes a PBP with low affinity for beta-lactams
Antipseudomonal Penicillin
1 Type
Piperacillin/Tazobactam
What is the most common mechanism of resistance to beta-lactams?
Beta-lactamases
Group of enzymes with the ability to inactivate beta-lactams
S. aureus and Haemophilus specificity for penicllins
Beta-lactamase Inhibitors
3 Types and action
- Clavalanate Acid
- Sulbactam
- Tazobactam
Minimal antibacterial activity but inactivate beta-lactamase enzymes
ESBLs
Species and activity
Enterobacerales produces Extended spectrum beta-lactamases
Broader activity - work against penicillins and cephalosporins
Beta-lactamase Inhibitors are generally ineffective against ESBLs
Penicillin ADRs
4 Main points
- Type 1 hypersensitivity
- Rash (common for pts with mononucleosis or CLL)
- GI Upset and possibility for CDI
- Irritability and Seizures possible w/ renal insufficient patients
First Generation Cephalosporins
3 Types
- Cefadroxil
- Cefazolin
- Cephalexin
2nd Generation Cephalosporins
5 Types
- Cefaclor
- Cefotetan
- Cefoxitin
- Cefprozil
- Cefuroxime
3rd Generation Cephalosporins
6 Types
- Cefdinir
- Cefixime
- Cefotaxime
- Cefpodoxime
- Ceftazidime
- Ceftriaxone
1st Generation Cephalosporin Susceptibility
5 answers
- Gram-positive Cocci (e.g Staphylococcus)
- Streptococci
- E. Coli
- Proteus Mirabilis
- Klebsiella
3-5 are enterobacterales; if isolated from a hospital setting may be res
2nd Generation Cephalosporin Susceptibility
1st Generation +
1. H. influenzae
Drugs in this generation are unique; perform susceptibility testing
Third Generation Cephalosporin Susceptibility
- S. pneumoniae
- MSSA
- H. influenzae
- N. gonorrhoeae
- N. meningitidis
- E. coli
- Klebsiella
- Proteus
- Salmonella
- Pseudomonas aeruginosa
May retain ability against some beta lactamase producing H. influenzae