chemotherapy part 1 Flashcards
Ludwigs angina
- a serious, life-threatening ______ or _____ infection of the floor of the mouth, usually occuring in adults with concomitant _____ infections
- may obstruct the airways, necessitating _____
- mixed infections: _____ and _____
- alpha hemolytic streptococci, staphylococci and bacteroides groups
- facial space infection with involvement of _____, _____, and _____ spaces
- external signs may include bilateral _____ facial edema around _____ and upper _____
- dysphagia, odynophagia, difficulty breathing, and pain
life threatening cellulitis connective tissue dental tracheotomy aerobes anaerobes submandibular sublingual submental lower mandible neck
past and present
- US centers for disease control estimates that 90000-200000 deaths occur annually due to nosocomial infections
- staph aureus resistant to _____, _____, _____ due to specific genes
- bacteria cold transfer these resistant genes among themselves
- hospitals today are plagued with MRSA and VRE
- viral disease
penicillins
erythromycin
tetracycline
future
drug resistance is becoming a worldwide concern
-gonorrhea and typhoid fever are becoming more difficult to treat
-TB and malaria are growing more resistant to Rx
-60% nosocomial infections are MDR
only 5 new classes of antibiotics in the past 40 years!
- _____ (linezolid)
- _____ (daptomycin)
- _____ (retapamulin
- _____ (dalfopristin)
- _____ (tigecycline)
- linezolid is most promised
- combination therapy to treat TB to avoid resistance
oxazolidinones lipopeptides pleuromutalins streptogramins glycylcyclines
history of antibiotics
- 1900 paul ehrlich
- ‘Magic Bullet’
- salvarsan: fuchsin and mercury to treat _____
- sir alexander flemming: _____
domagk: _____ from ‘Prontosil’ - _____
syphilis
penicillium notatum (a fungus)
red dye
definitions
- _____: substances that act against or destroy infections (_____/_____/_____)
- antibiotics: substances produced by _____ that can destroy or suppress the growth or multiplication of bacteria to prevent the _____ of _____
- antimicrobials/antibacterial: _____ or _____ substances used to suppress growth or kill _____/ _____ cell organisms
- antivirals/antifungals/antiprotazoans/antihelminths
anti-infective agents fungal viral bacterial bacteria action bacteria natural synthetic bacteria single
MOA of antibacterial action
- inhibition of _____ synthesis
- alteration of the _____
- inhibition of ribosomal _____ synthesis
- suppression of _____ synthesis
- inhibition of _____ synthesis
cell wall cell membrane permeability protein DNA folic acid
inhibition of cell wall synthesis
- cell walls contain alternating _____ units, cross linked with _____ linkages
- bacterial enzymes termed _____ catalyze the formation of the wall by incorporating new peptidoglycan strands
- _____ antibiotics competitively inhibit this final process, thus preventing a rigid cell wall forming
- internal osmotic pressure causes _____
- -_____ (amoxicillin; penicillin V)
- -_____ (cephalexin)
peptidoglycan amide penicillin binding proteins peptidoglycan beta-lactam lysis penicillins cephalosporins
alteration in cell membrane
- bacterial cell membranes contain a _____ component
- this maintains cell membrane integrity
- antibiotics such as polymyxin B displace _____ and _____ from the cell membrane and disrupt membrane
lipopolysaccharide
Ca++
Mg++
inhibition of protein synthesis
- bacterial ribosomes have subunits such as _____ and _____ where proteins are synthesized
- antibiotics bind to the _____ site of these subunits and inhibit _____
- this inhibits binding of _____ to _____
- 30S: _____, _____
- 50S: _____, _____
30S 50S p peptidyl transferase tRNA mRNA tetracyclines aminoglycosides macrolides clindamycin
inhibition of nucleic acid synthesis
- _____ of DNA, DNA _____, recombination and DNA repair occurs by _____ and _____ enzymes
- _____ and _____ inhibit these enzymes
- results: vacuoles, filamentation and cell lysis
supercoiling replication DNA gyrase topoisomerase fluoroquinolones metronidazole
inhibition of folic acid synthesis
- humans fo not produce folic acid, it is available from _____ sources
- bacteria synthesize their own _____ from _____ (Para amino benzoic acid)
- PABA converts into _____ acid by enzyme _____
- _____ are structural analogues of PABA and block the conversion
- _____ and _____
–trimethoprim prevents eventual production of folic acid
dietary folic acid PABA dihydrofolic dihydrofolate reductase sulfonamides sulfamethoxazole trimethoprim
antibiotic resistance
1st mechanism – we give the patient an antibiotic and the antibiotic goes into the bacteria but the bacteria creates its own _______, which throws the antibiotic right out of its structure
2nd mechanism – it modifies the _____ by creating an _______ protein to our antibiotic and our antibiotic cannot be taken up because of the configuaration of change
3rd mechanism – formation of ______, a plasmid can transmit genetic info and relay all mechanisms of resistance to all other bacteria through gene transfer
Basically tells other bacteria
Plasmid – can transmit knowledge of mechanisms of resistance to bacteria
4th mechanism – the bacteria which has a ____ where our antibiotic would’ve acted requires a ______ for that target
-the antibiotic should’ve fit right in but the receptor could be the ribosome etc. it required a receptor
The bacteria modified its drug target structure
5th mechanism – they can inactivate the antibiotic by various _______
-it creates enzymes to inactive this drug
efflux pump cell wall impermeable protein plasmids receptor enzyme
superinfections
-a _____ infection while patient is being treated for a _____ infection
–more likely with _____
–may also be opportunistic infections with fungi such as Candida albicans and histoplasmosia
may occur due to inhibition of normal flora such as _______ and _______
-often difficult to treat
-drug resistant microbes usually involved
-genetic messages (plasmids, transposons) transferred to new bacteria
new primary broad spectrum antibiotics C.diff pseudomembranous colitis
antibiotic adverse effects
- antibiotic teratology: FDA class B or C
- _____: genetic or acquired by drug use. _____, _____ may cause sudden syncope and cardiac arrest
- _____: reduced neutrophil counts with septicemia and shock. may be caused by _____ and _____
- superinfections: destruction of normal flora (diarrhea and pseudomembranous colitis)
- _____: CYP 450 induction or decreased GIT absorption of OC (loss of ________)
- photosensitivity, stevens johnson syndrome, allergy and toxicity
long QT syndrome fluoroquinolones macrolides agranulocytosis sulfonamides penicillins oral contraceptives contraception
