This presentation gives an outline of important considerations for use of antibiotics, their classification, synergism or antagonism, development of resistance and hypersensitivity reactions.

1. 1©Capt. Dr. Muhammad Aamir Farooq | dr.aamirfarooq@hotmail.com

2. Antibiotics
2©Capt. Dr. Muhammad Aamir Farooq | dr.aamirfarooq@hotmail.com

3. Intro
• CHEM substance produced by microorganism
• Having bactericidal or bacteriostatic action
• Antibiotics are produced by
• Moulds
• Actinomyces
• Bacteria
• Synthesized
• Excessive use creates resistance to these drugs
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4. Aim
To brief about imp consd for use of antibiotics, their cl,
synergism or antagonism, dev of resistance & hypersensitive
reactions
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5. Seq
• Hist
• Cl of Antibiotics
• Comb of Drugs
• Hypersensitivity
• Antimicrobial Resistance (AMR)
• Reasons for Failure of Antibiotic Therapy
• Imp consd for Antibiotic Use
• Concl
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6. Hist
• In 19th century Pasteur noted antagonistic eff of organism on others
• Paul Ehrlich dev idea of selective toxicity
• In 1928 Sir Alexander Fleming observed eff of Penicillium notatum
on Staphylococcus
• Penicillin was isolated in 1939
• In 1944 Selman Waksman & Albert Schatz isolated streptomycin
from Streptomyces griseus
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7. Cl of Antibiotics
• CHEM Structure
• Tetracycline
• Penicillin
• Aminoglycosides
• Macrolides etc
• Spectrum of Activity
• Narrow spectrum
• Broad spectrum
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8. Cl of Antibiotics
Activity Against Bacteria
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9. Cl of Antibiotics
Mechanism of Action
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10. Comb of Drugs
• Antibiotic Synergism
• Activity of two drugs in comb is greater to sum of their indep activity
• Antibiotics having synergistic eff incl:-
• Penicillin
• Cephalosporin
• Bactracin
• Vancomycin
• Aminoglycosides
• Polymyxins 10

11. Comb of Drugs
• Antibiotic Antagonism
• Activity of two drugs in comb is less to sum of their indep activity
• Antibiotics having antagonistic eff incl
• Chloramphenicol
• Tetracycline
• Erythromycin
• Clindamycin
• Sulphnamides
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12. Hypersensitivity
• Exaggerated response of immune sys to antibiotic
• Reactions may be damaging, uncomfortable, or occasionally fatal
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13. Hypersensitivity
• Desensitization protocols are designed to treat type-1 hypersensitivity
• Induction of drug tolerance without an adverse reaction
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14. Antimicrobial Resistance (AMR)
• Ability of a microbe to resist the eff of medication to which they
were once sensitive
• Resistance arises through one of the fol ways:-
• Natural resistance
• Genetic mutation
• Misuse of antibiotics
• Resistant microbes are inc difficult to treat
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15. AMR
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Mechanism of AMR

16. AMR
• Causes of AMR
• Inappropriate prescribing of antibiotics
• Uncontrolled sale in many low income ctys
• Missing doses when taking antibiotics
• Antibiotic use in livestock
• Lack of hygine
• Vol of antibiotic prescribed
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17. (AMR)
• Prevention
• Dec duration of antibiotic treatment
• Limit use of antibiotics in animals
• Min antibiotic usage
• Altn therapy
• Dev of new drugs
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18. Reasons for Failure of Antibiotic Therapy
• Wrong diagnosis e.g. viral not bacterial infection
• Unsusceptible organism
• Susceptible organism later dev resistance
• Mixed infection & insufficient antibiotic cover
• Comb of incompatible antibiotics
• Super infection by resistant opportunistic pathogen occurred
• Re-infection by original or by other pathogen
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19. Reasons for Failure of Antibiotic Therapy
• Inadequate drainage or presence of foreign body in surgeries
• Access to site of infection because of inflammation, cellular debris,
tissue destruction & abscessation
• Animal def mechanism weakened due to disease, malnutrition
• Incorrect dosage or route of adm
• Expired or substandard products
• Poor nursing & inadequate nutrition
• Stress of disease
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20. Imp Consd for Antibiotic Use
• Obtaining an accurate diagnosis of infection
• Ident opportunities to switch to narrow spectrum
• Understanding drug pharmacodynamics & efficacy
• Recognizing the adverse eff of drugs on the host
• Correct dosage & route of adm
• Nutrition state of animal especially protein & vitamins
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21. Concl
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©Capt. Dr. Muhammad Aamir Farooq | dr.aamirfarooq@hotmail.com

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©Capt. Dr. Muhammad Aamir Farooq | dr.aamirfarooq@hotmail.com