3. Disadvantages from taking medication
without doctor guide
•Emergency of Resistance.
•Drug toxicity.
•Cost.
•Drug dose.
•Interaction of the drug with other disease.
•Susceptibility of the pathogenes to the drug.
•Time consuming.
4. Antimicrobial agents:
• Chemical and therapiotic agents that acts against bacteria, viruses,
fungi and parasite.
• Antibiotic ------ Natural product from microorganism.
• Chemotherapy ------ Chemically synthetic or semi synthetic agent.
5. • Bacteriocidal: Killing effects
• Bacteriostatic: Inhibition
• Narrow spectrum: Narrow rang of
Microorganism.
• Broad spectrum: Wide range of M.O
• Minimum Inhibitory Concentration: Lowest conc.
Of antimicrobials that stop the growth of M.O
• Minimum Bacteriocidal Concentration: Lowest
concentration of antimicrobials that stop the growth
of M.O.
• Synergism: The effects of 2 antimicrobials better
than antimicrobial alone.
• Antagonistic effects: Effects of 2 antimicrobial is less
than antimicrobial alone.
6. Antimicrobial action:
• Inhibition of cell wall synthesis.
• Inhibition of Cell membrane synthesis.
• Inhibition of protein synthesis.
• Inhibition of Nucleic acid synthesis.
• Metabolic antagonism.
9. Penicillin:
•From Penicillium notatum.
•Discovered at 1928 and used at 1938.
•Active part is β-lactam ring.
•Inter through penicillin binding proteins.
•Resistant by:
• Production of β-lactamase.
• Lack or alteration of PBPs.
• Failure in activation of autolytic enzyme.
• Failure in synthesis of peptidoglycan (Mycoplasma).
•Side effect:
• Penicillin allergy.
• Types:
• Penicillin G Acid sensitive (IV and IM).
• Penicillin V Acid Resistant (Oral)
10. • Ampicillin:
• Broad spectrum antimicrobial (G+ve and some G-ve).
• Acid tollerant.
• Amoxicillin:
• Have wide range of activity against G+ve G-ve and some
Anaerobe)
• Could be taken orally.
• Amoxicillin-Clavulinic acid:
• More penicillinase resistant antimicrobial
• Monobactam:
• IV or IM antimicrobial that active against G-ve bacteria and resist
β-lactamase (e.g.: Aztreonam).
• Carpenems:
• Active against G+ve and G-ve bacteria and anaerobes except
bacteroides.
• Could reach CSF.
• Side effects:
• Skin rash, diarrhoea, vomiting, and Hypersensitivity.
11. Cephalosporins:
• Same as penicillin in action.
• Resistance:
• Poor permeation of bacteria (No entry).
• Lack or alteration of PBPs.
• β-lactamase production.
• Side effects:
• Hypersensitivity.
• Thrombocytopenia.
• 1st generation:
• Active against G+ve cocci except enterococci, moderate active
against E.coli, Klebsiella, proteus and some anaerobic.
• Cephalexin and Cephradin given orally.
• Could be used in UTI and RTI.
• Cephalexin used as post opersative prophylaxis.
12. • 2nd generation:
• Active against G+ve and G-ve (except pseudomonas) and some
anaerobe.
• 3rd generation:
• Less active against G+ve, but active against G-ve and moderate action
against pseudomonas.
• Have the ability to reach the CSF.
• 4th generation:
• Act against G-ve including enterobacter and Citrobacter Pseudomonas
and moderate sensitive against G+ve.
13. Bacitracin:
• From B. subtilus.
• Inhibit early cell wall synthesis in cell membrane (inhibit lipid
carrier).
• Poor absorbance from GIT.
• Very active against G+ve bacteria.
• Used as ointment.
• Side effect:
• Kidney damage.
• Nitrogen retention.
14. Vancomycin:
• From S. orientalis
• Bind with peptide chain inhibiting transpeptidation.
• Side effects:
• Skin rash.
• Kidney damage.
15. Inhibition of cell membrane:
• Polymexin B:
• Disrupt plasma membrane structure.
• Bacteriocidal for G-ve and G+ve.
• High toxic used as Ointment.
• Side effects:
• Nephrotoxic.
• Neurotoxic.
16. Inhibition of Protein synthesis:
•Inhibition of 30 S rRNA:
• Aminoglycoside.
• Tetracyclins
•Inhibition of 50 S rRNA:
• Chloramphenicol.
• Lincosamide (Lincomycin and clindamycin).
• Macrolides (Erythromycin, Clarithromycin).
• Fusidic acid Affect Elongation factor G.
17. Aminoglycoside:
• Streptomycin, Neomycin, Kanamycin, Amikacin,
Gentamicin, and tobramycin.
• Bacteriostatic inhibit 30 S rRNA.
• Active at alkaline PH.
• Broad spectrum (G+ve and G-ve and Mycobacterium).
• Give synergistic effect with penicillin.
• In blood culture aminoglycoside inhibited by Na
polyanithol sulfonate.
• Resistance by:
• Deficiency in Ribosomal receptor.
• Lack of permeability to the drug (transportation is oxygen
dependent).
• Side effect:
• Nephrotoxic and Ototoxic.
18. Tetracyclins:
•Inhibit G+ve, G-ve, Rickettsia, Chlamydia,
Mycoplasma, Brucella, Yersinea and Vibreo.
•Bacteriostatic in action.
•Have poor penetration to CSF.
•Side effects:
• Gastrointestinal upset (Nausea, Vomiting, and Diarrhoea).
• Skin rash.
• Deposition in bone structures and teeth particularly in
fetus.
19. Chloramphenicol:
•From S. vensuelae (Now synthesized).
•Wide distributed in all body fluid including CSF.
•Inactivated in liver and secreted in urine in
inactive form.
•Bacteriostatic in action.
•Resistant by production of Chloramphenicol
acetyl transferase.
•Side effects:
• GIT upset.
• Aplastic anaemia.
• Gray fetal syndrome. (Have no develop liver so No
inactivation).
20. Lincosamide (Lincomycin and Clindamycin):
• From S. licolnsis.
• Very active against bacteroides and other anaerobes.
• Cause Pseudomembranous colitis.
• Acid stable.
• Cold not penetrate CSF.
21. Macrolides (Erythromycin, azithromycin
and Clarythromycin):
•From S. erythrus.
•Resistance by alteration of rRNA receptor.
•Active at alkaline PH.
•Active at G+ve, G-ve, Chlamydia, Mycoplasma
and Legionella.
•Side effects:
• GIT upset.
• Fever.
• Affect liver cells causing hepatitis.
22. Quinolones:
•Block DNA gyrase.
•E.g.: Nalidixic acid, Oxolinic acid, Ciprofloxacin,
Ofloxacin, Norfloxacin, Pefloxacin, and
Nitrofurantoin.
•Used in UTI.
•Active against G-ve, G+ve, Haemophilus,
Pseudomonas and Mycobacterium.
•Side effect:
• Nausea, headache, and dizziness.
• Skin rash.
• Impaired liver function.
Inhibition of Nucleic acid:
23. Rifampin:
•Active against some G+ve, G-ve, Enteric cocci,
Mycobacterium, Chlamydia and pox virus.
•Bind with RNA polymerase (inhibit RNA
synthesis).
•Could penetrate inside phagocytic cells.
•Side effects:
• Orange pigment in urine and sweat.
• Skin rash.
• Thrombocytopenia.
• Impaired liver function.
24. Metabolic antagonistic:
• Bacteriostatic for some G+ve and G-ve bacteria.
• Inhibit folic acid synthesis.
• Synergistic effect obtained from Cotrimoxazole
(Trimethoprim and Sulphomethoxazole).
• Side effects:
• Hypersensitivity.
• Fever and skin rash.
• GIT disturbances.
• Depression of bone marrow.
• Liver and kidney function abnormality.
Sulphonamide and trimethoprim:
25. Antimicrobial susceptibility pattern:
• Kirby Bauer agar disk diffusion methods:
• Aim:
• To perform standard sensitivity test on agar media.
• Test requirements:
• Media: Muller & Hinton agar and Broth
media
• Antimicrobial disks: Multi or single disks
• STD turbidity tube: McForland tube (Bacl2 + H2So4)
• Pure culture from organism under test.
26. • Test Procedure:
• Make a suspension by touching more than 10 colonies and
emulsify on M&H broth.
• Incubate for 30 min in water bath.
• Compare the turbidity with 0.5 McForland tube (contain 0.05 ml of
1.16% Bacl2 + 9.95 ml of 1% H2SO4).
• Streak on M&H agar using Ca++ alignment swab 3 times inverting
the plate 60 each time.
• For H influenzae, S. pneumoniae, and Neisseria we use M&H
supplemented with Heated sheep Blood and for Streptococci we
use Blood agar.
• Put the disk on the center of the plate allowing 1.5 cm distances
from the edge of the plate and 1 cm between each disks (the plate
take about 8 disks).
• Incubate at 37C for exactly 18 hours.
• Read the diameter of the disk using ruler and compare it with a
STD.
• Report your results as HS, MS, SS, R.
27. Same plate comparative methods (Stock)
• We culture control strain on the center of the plate and tested
organism on the two edges. Put the disks between.
28. Factors affect antimicrobial agar disk diffusion
method:
Type of the medium.
Depth of the medium (4 mm)
Surface of the medium
Supplement in the medium (mg and ca) and Blood
Moisture of the medium
pH of the medium
Source and expiry date of antimicrobial agents
Concentration of antimicrobials in the disk
Distribution of disks on the surface of the medim.
Nature of organism
Inoculum size.
Incubation temperature.
Incubation condition.
Incubation time.
29. Dilution methods:
•This used to detect antimicrobial susceptibility to
slow growing M.O and anaerobic.
•It could be carried out on Microtiter plate or test
tube.
•Also it used to detect MIC to antimicrobials
•We make serial dilution of antimicrobials and add
5 drops from 106 bacterial suspension and
incubate at 37 C, then read about turbidity which
indicate resistance and clearance which indicate
sensitivity, and detect the MIC.
30. Epsiloid test (E test):
• Used for detection of MIC in plate procedure.
• We could detect more than one MIC at the same time.
31.
32. Antimicrobial Resistant test:
•β lactamase test:
• Cefinase β lactamase disk:
• Using disks contain nitrocefin, we add suspension of
Microorganism and see the development of Pink-Brown color
within 10 min indicating β lactamase production.
• Acidimetric technique:
• Using citrate buffered penicillin and phenol red. Penicillin
destroyed by the enzyme to give penicilloic acid which change the
color from red into yellow.
• Iodometric technique:
• Using phosphate buffered penicillin and starch-iodine complex,
penicilloic acid prevent binding of starch with penicillin which
convert the color from blue to colorless.
