Antibiotics, Classes and MOA

1. Antibiotics in Poultry
Muhammad Arslan Musa
M.Sc. (Hons.) Poultry Science
arslan2062@gmail.com

2. Antibiotics
• Antibiotics are the drugs used to treat or prevent bacterial diseases.
Antibiotics may be
Bacteriostatic (inhibit bacterial growth)
Bactericidal (kill bacteria)
• Antibiotics are used in poultry
- To growth performance
- Disease prevention (Prophylaxis)
- Treatment

3. Mode of Action of Antibiotic
 Bactericidal
• Target bacterial cell wall (Penicillines, Cephalosporines)
• Target cell membrane (Polymixins)
• Target essential bacterial enzymes (Quinolones,Sulfonamides)
 Bacteriostatic
• Target synthesis of protein (Tetracycline, Macrolides, Aminoglycosides,
Amphenicol)

4. Antibiotics Targeting Cell wall

5. Penicillins
• Cause bacterial cell wall breakdown by inhibiting the formation of cell wall
• Examples are penicillin, amoxicillin and ampicillin
• Amoxicillin and ampicillin effective against E.coli infection, Salmonella
spp., Pasturella multocida and Necrotic enteritis

6. • Penicillin G is effective against Necrotic enteritis and Fowl cholera
• Amoxicillin has good absorption through oral administration but poor
stability in water so, feed administration is preferred
• Ampicillin has good stability in water but show low bioavailability through
oral administration

7. Cephalosporin
• Ceftiofur is only approved drug of this class for poultry
• Disrupts the peptidoglycan layer synthesis of bacterial cell wall
• Have 5 generations and each later generation show wider spectrum
• Ceftiofur is highly effective against Garm –ve bacteria
• Effective against yolk sac infection and colibacillosis

8. Antibiotics Targeting Protein
Synthesis

9. Tetracyclines
• Most of them derived from Streptomyces species
• Inhibit bacterial multiplication by inhibiting protein synthesis (30S inhibitor)
• Members includes tetracycline, doxycycline, oxytetracycline,
chlortetracycline
• Broad spectrum and effective against bacteria, protozoa, anaerobes and
intracellular organisms

10. • Highly used in poultry due to its wide spectrum, safety margin and no
withdrawal time for eggs
• Good absorption in intestine but forms chelates with bivalents mainly Ca
and Mg
• Poor water absorption at neutral pH and good solubility at 5 pH
• Mainly used against mycoplasma, fowl cholera and infectious coryza
• E.coli show resistance against tetracyclines

11. Aminoglycosides or
Aminocyclitols
• Derived from Streptomyces
• Inhibit protein synthesis (30S or 50S)
• Very effective against staphylococci and aerobic Gram –ve bacteria
(i.e. Enterobacteriaceae and Pseudomonas)
• Also exhibit post-antibiotic effects
• Only 3 aminoglycosides are used in poultry
• i.e. Gentamycin, Neomycin and Streptomycin

12. • Noemycin has local effect in GIT as it’s absorption is poor and used
to treat enteric infections i.e. Colibacillosis
• Streptomycin is partially absorbed from GIT and effective against
E.coli infections
• Hygromycine and Spectinomycin are only aminocyclitols used in
poultry
• Hygromycin is mainly used as anthelmintic and spectinomycin
mainly used agains E.coli due to low absorption

13. Macrolides/ Lincosamides/
Tiamulin
• Inhibit protein synthesis (50S inhibitor)
• Macrolides includes Tylosin, Tilmicosin, Eryhthromycin
• Tylosin has low absorption in GIT and most effective drug against
Mycoplasma treatment and restore egg production
• Tylosin is also effective against necrotic enteritis
• Tilmicosin is rapidly absorbed from GIT effective against Mycoplasma
and Fowl cholera

14. • Tiamulin is very effective against Mycoplasma and Spirochetosis
• Tiamulin shows interaction with Ionophores except lasalocid and cause
accumulation in liver and intoxication signs
• Tylvalocin tartrate (Aivlosin®) is costly antibiotic and can eliminate MG

15. • Erythromycin has good absorption and effective against Gram
+ve bacteria i.e. Staphylococcus aureus
• Lincomycin is only Lincosamide used in poultry and effective
against gram-positive anaerobic bacteria
• It has good absorption from GIT and mainly used against
necrotic enteritis and spirochetosis

16. Amphenicol
• 50S inhibitor so, inhibit protein synthesis
• Members include Chloramphenicol, Florphenicol (derivative of
chloramphenicol)
• Florfenicol is effective against Gram –ve (Salmonella, E.coli), anaerobes
and intracellular organisms (Mycoplasma)
• Also effective against Fowl cholera and Infectious coryza

17. Antibiotics Targeting Essential
bacterial enzymes

18. Quinolones (Gyrase inhibitors)
• Broad spectrum and most effective bactericidal antibiotics for poultry
• Inhibit bacterial multiplication through inhibiting DNA replication by
targeting DNA gyrase
• Also targeting topoisomerase IV (Topo IV is primary target in Gram +ve
and secondary in Gram –ve)
• Very effective against Salmonellosis, Colibacillosis and Fowl cholera

19. • Divided into 4 generations and each later generation has wider activity
• 1st generation (Nalidixic acid)
• 2nd generation (Norfloxacin, Ciprofloxacin, Ofloxacin, Enrofloxacin)
• 3rd generation (Levofloxacin, Gatifloxacin)
• 4th generation (Motifloxacin)
• Enrofloxacin is widely used in poultry and have good safety margin

20. Sulfonamides
• Obtained through chemical synthesis and broad spectrum
bacteriostatic activity
• Inhibit DNA and RNA synthesis
• It actually inhibits the PABA (paramainobenzoic acid) that is
required for folic acid synthesis (folic acid required to divide
bacteria)

21. • Effective against E.coli, Salmonella, Streptococcus species and
Staphylococcus aureus
• Examples includes sulfamethizole, sulfaquinoxaline, trimethoprim,
sulfadimethoxine
• Their use in poultry is limited due to narrow safety margins
• Sulfa drugs are also effective against coccidiosis but may show interaction
with Ionophores

22. Miscellaneous Antibiotics
• Nitrofurans ( Furaltadone, Fulazolidone)
• Polypeptides
• Bactiracin is antibiotics of this group used in poultry
• Not absorbed from GIT so, cause local effect
• Normally used to prevent Necrotic enteritis
• Enramycin
• Polymixins
• Polymixin E (Colsitin)

23. • Colisitin is very effective against E.coli
• Enrmaycin is effective against Necrotic enteritis
• Furazolidon and Furaltadon is highly effective against
Salmonella

24. Thanks