MMI review Flashcards
cautions w antibiotic therapy
specificity, resistance, superinfections
specificity
narrow-spectrum antibiotics needed
resistance
mutations in drugs, nosocomial infections
superinfections
broad spectrum antibiotics; CNS active meds
3 pathways of resistance
- bacteria spread among people
- bacteria to bacteria communication
- biochemical mechanisms
- Bacteria spread among people
mutations occur 1/10 mill
- Bacteria to bacteria communication
bacteria exposed to tx creates resistance genes, r-plasmid=site for resistant genes
transfer via conjugation (transferring plasmids)
Transformation
absorbing resistance gene plasmid. transponson- jumping genes, carrries DNA info between bacteria
- Biochemical mechanisms
enzymes- essential enzyme pathway desensitization
receptor site alteration
decreased drug intake
resistant pathogens
staphylococcus aureus: MRSA
enterococci: VRE
mycobacterium: tuberculosis
what causes an infection
pathogenicity: organisms ability to evade body defenses (bacteria, virus, fungus, parasite
entry into the body past endogenous defenses
mechanisms of entering body past endogenous defenses
1: strength in numbers
2: toxin production
common world wide pathogens
TB, cholera, E-coli, enterococci, staph. aureus, acinetobacter
Viral infections
more contagious ex. flu, cold, laryngitis, croup. symptom management with antivirals & best protection with vaccination
Bacterial infections
less common, less contagious, respond to antibiotics
ex. strep, pneumonia
Gram Neg bacteria
thin peptidoglycan, has 2 membranes and looks pink. lipid-a endotoxin
ex. E-coli, salmonella, pseudomonas
Gram Pos bacteria
thick peptidoglycan, looks purple
narrow spectrum antibiotics
more specific, less resistance, requires ID of organisms ex. vancomycin, penicillin
broad spectrum antibiotics
less specific, more resistance potential, doesn’t require ID of organism ex. carbapenems
antibiotic emperic tx
based on suspected bacteria, broad spectrum, started ASAP
antibiotic focal tx
need culture and sensitivity results= focused treatment, initiated once results are known
narrow spectrum
tx protocols: 3 steps
1: treat according to clinical presentation & patient history ( emperic therapy)
2: use bugs and drugs resource
3: confirm with culture & sensitivity (focal therapy)
4 classes of antimicrobial MOA
- cell wall synthesis inhibitors
- protein synthesis inhibitors
- nucleic acid inhibitors
- antimetabolites
cell wall synthesis inhibitors
penicillins, cephalosporins, bacitracin, vancomycin