Drug resistant bacteria (seven listed)
-E.faecium
-Staph aureus
-Enterbacter,
-Klebsiella
-Pseudo aeruginosa
-Acine baumannii
-C. diff
Four
... [Show More] basic actions of bacterial drug resistance
•Decrease the concentration of a drug at its site of action
•Inactivate a drug
•Alter the structure of
drug target molecules
•Produce a drug antagonist
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Spontaneous mutation
•Random changes in a microbe's DNA
•Resistance to one drug
Conjugation in bacteria
•Extrachromosomal DNA is transferred from one bacterium to another
•Gram-negative bacteria
•Multiple drug resistance
Nosocomial infections
•Health care-associated infections (HAI)
Superinfection
•New infection that appears during the course of treatment for a primary infection
•Because superinfections are caused by drug-resistant microbes, they often are difficult to treat
Public Health Action Plan to Combat Antimicrobial Resistance
•Focus Area I: Surveillance
•Focus Area II: Prevention and Control
•Focus Area III: Research
•Focus Area IV: Product Development
Penicillin MOA
•Weaken the cell wall, causing bacteria to take up excessive water and rupture
•Active only against bacteria undergoing growth and division
•Bactericidal
-beta-lactam family
*Give macrolides when pt is allergic to PCN
Three factors to bacterial resistance to PCNs
•Inability of penicillins to reach their targets
•Inactivation of penicillins by bacterial enzymes
•Production of penicillin-binding proteins (PBPs) that have a low affinity for penicillins
Gram-negative cell envelope
•Three layers
•Thin cell wall and an additional outer membrane that is difficult to penetrate
Gram-positive cell envelope
•Only two layers
•Relatively thick cell wall that is easily penetrated
Beta-Lactamases
•Bacteria can produce a large variety of these enzymes specific for penicillins (and other beta-lactam antibiotics)
-These enzymes inactive PCN and other antibiotics that are apart of the beta-lactam ring family
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Penicillin G & V
-Narrow spectrum abx
-Used for strep and syphillis
-Sensitive to beta-lactamases/penicillinase
Amoxicillin/Amipicillin (PCN)
-Broad spectrum
-Used for strep, AOM, lyme disease in children < 8y/o
PCN resistant to penicillinase/ beta-lactamases enzymes from bacteria
•Nafcillin
•Oxacillin
•Dicloxacillin
-Used for Staph aureus and Staph epidermis
-Can be given PO
Beta-lactamase inhibitors combined with PCNs
-Beta-lactamase inhibitors
-Clavulanic
-tazobactam
-sulbactam
•Extends antimicrobial spectrum when combined with PCN
•Ampicillin/sulbactam [Unasyn]
•Amoxicillin/clavulanic acid [Augmentin]
•Piperacillin/tazobactam [Zosyn]
Ticarcillin/piperacillin effective against
-pseudomonas
-enterobacter
-bacteroides fragilis
-klebsiella
Cephalosporins
•Most widely used group of antibiotics
•Beta-lactam antibiotics
•Similar to penicillin structure
•Bactericidal
•Usually given parenterally
•Low toxicity
-weaken bacterial cell wall
-Cross allergy with PCN, do not give if pt allergic to PCN
Cephalosporins (MOA)
•Bind to penicillin-binding proteins (PBPs), disrupt cell wall synthesis, and cause cell lysis
•Most effective against cells undergoing active growth and division
Beta-lactamases (cephalosporinases) by generation
•First-generation destroyed by these enzymes
•Second-generation less sensitive
•Third-, fourth-, and fifth-generation agents more resistant than first- and second-generation agents
First generation (cephalosporins)
Cefazolin (IM/IV)
Cephalexin (PO)
Cefadroxil (PO)
*Main use- pre surgical prophylaxis
*Mostly gram (+)
Second generation (cephalosporins)
-cefoxitin (Anerobeic bacteriodes fragilis)
-cefaclor
-cefotetan
-cefprozil
-cefuroxime (good for URI Pneumonia)
*Mostly gram (+) coverage
Third Generation (Cephalosporins)
-Cefoxtamine
-Cefdinir
-Cefditoren
-Cefixime
-Cefpodoxime
-Ceftazadime
-Ceftibuten
-Ceftriaxone
*All penetrate spinal fluid and have good gram neg coverage of klebsiella, serratia, gonorrhea, psuedomonas [Show Less]