Antiinfectives I Flashcards
How do we divide antimicrobials?
Antibacterics - against bacteria
Antimycotics - against moulds and yiests
Antivirotics - against viruses
Antibacterics according to chemical structure
Antibiotics - products of metabolism of organisms
Chemotherapeutics:
* Sulphonamides
* Chinolones
* Nitrofurans
Antibiotics are produced by what, and function how
Bacteria and microscopic fungi
Kill microorganisms or stop their growing
Classify antibiotics according to effect on microorganisms
- Bacteriostatic
- Bactericidal
Bacteriostatic antibiotics
Suppress growth of bacteria
Acute diseases
- Macrolides
- Tetracyclines
- Amfenicols
- Diterpens
- Lincosamides
- Sulphonamides
Bactericidal antibiotics
Kill bacteria
Chronic diseases
- Penicillins
- Cephalosporins
- Monobactams
- Carbapenems
- Polyptides
- Glycopeptides
- Ansamycins
- Chinolones
Classify antibiotics according to mechanism of action
- Cell wall synthesis inhibitors: b-lactams, glycopeptides
- Permeability of cell membrane: polyens, polymyxin, nystatin, amphotericin B
- Protein synthesis inhibitors: tetracyclines, amphenicols, aminoglycosides, macrolides, pleuromutilins, lincosamides, steroid substances (fusidic acid)
- Nucleic acid synthesis inhibitors: rifamycins, griseofulvin
Classification according to spectrum of action
Narrow-spectrum antibiotic - penicillin G, streptomycin
Broad-spectrum antibiotic - tetracyclines, amfenicols
Slightly-broad spectrum - semi-synthetic penicillins, aminoglycosides, macrolides
Anti-staphylococcal antibiotics
macrolides, lincomycin, vancymycin, penicillinase-resistant penicillins, cephalosporins of some generations, rifampin
Against G- bacteria
aminoglycosides, polymyxins, cephalosporins, tetracyclines, amphenicols
Against yiests and fungi
amphotericin B, nystatin, grizeofulvin, candicidin, natamycin, trichomycin
Topical application
bacitracin, neomycin
Requirements for an ideal antibiotic
- Selective target
- Bactericidal
- Narrow spectrum
- High therapeutic index
- Few adverse reactions
- Various routes of administration
- Good adsorption
- Good distribution to the site of infection
- Emergence of resistence is slow
Name adversal side effects of antibiotics
allergic reaction
emesis
salivation
diarrhea
reduction of vit. B synthesis
development of resistency
difficulties in processing milk fermented products
occurence of residents in meat, animal products
Resistance can be
Primary - natural
Secondary - obtained
Antibiotics according to chemical structure
- Penicillins
- Cefalosporins
- Tetracyclins
- Amfenicols
- Polypeptides and glycopeptids
- Aminoglycosides
- Macrolids
- Lincosamids
- Ansamycins
- Diterpens
- Antibiotics with different structure
Beta-lactams are
Penicillins and cefalosporins
Testing for effectiveness of antibiotics
- Diffusion - discs diffusion method (qualitative) or E-test (quantitative
- Dilution - microdilution and macrodilution
Antibiogram is
Qualitative method
Antibiotics discs put on bacterial culture
Measurement of inhibition zone
Define MIC (minimum inhibitory concentration)
concentration of drug in blood (or blood plasma) that can affect inhibition of growth and development of microorganisms
E-test
Quantitative method
Stripes with concentration gradient
MIC = intersection of the growth inhibition zone and calibrated test strip
