Lincosamides are a class of antimicrobial drugs that include lincomycin, clindamycin, and pirlimycin. They work by binding to the 50S subunit of bacterial ribosomes and inhibiting protein synthesis. Lincosamides are effective against many gram-positive bacteria and anaerobes. Resistance can develop through enzymatic inactivation of the drug or methylation of ribosomal RNA. Lincomycin is used to treat various infections in livestock through feed/water administration or injection. Pirlimycin is used to treat mastitis in dairy cattle. Several combination products containing lincomycin are also approved to treat infections in food animals. Precautions include not using lincosam

1. Antibiotics Groups
Lincosamides

2. Description
 Lincosamides are derivatives of an amino acid and a sulfur-
containing galactoside.

3. Cont. …
 The lincosamide class of antimicrobial drugs includes:
1. Lincomycin
• It was isolated in 1962 from the fermentation product
of Streptomyces lincolnensis subsp. lincolnensis.
2. Clindamycin
• It is a semi-synthetic derivative of lincomycin.
3. Pirlimycin
• Pirlimycin is an analog of clindamycin.

4. Cont. …
 Lincomycin and pirlimycin are approved for use in food-
producing species.
 Clindamycin has a wider spectrum of activity than does
lincomycin, but it is not approved for use in food-producing
animals.

5. Mechanism of Action
 The lincosamides inhibit protein synthesis in susceptible
bacteria by binding to the 50S subunits of bacterial
ribosomes.
 Thus, inhibiting peptidyltransferases; interference with the
incorporation of amino acids into peptides occurs thereby.

6. Spectrum
 Lincosamides may be bacteriostatic or bactericidal depending
on;
1. Concentration of drug at the infection site
2. Bacterial species and bacterial strain
 They are active against:
1. Many Gram-positive bacteria
2. Most obligate anaerobes
 They are not effective against most Gram-negative organisms.

7. Cont. …
 Lincomycin is effective against:
1. Staphylococcus species
2. Streptococcus species (except Streptococcus faecalis)
3. Erysipelothrix insidiosa
4. Leptospira pomona
5. Mycoplasma species

8. Resistance
 Specific resistance
– Resistance specific to lincosamides results from the enzymatic
inactivation of these drugs.
 Cross resistance
– There is cross-resistance among macrolides, lincosamides, and
streptogramin group B antibiotics (MLSB resistance).
– With this form of resistance, binding of the drug to the target is
prevented on account of methylation of the adenine residues in the
23S ribosomal RNA of the 50S ribosomal subunit (the target).

9. Administration
Lincomycin
Drinking water treatment
 Lincomycin hydrochloride is added to feed or drinking water
to:
1. Control necrotic enteritis in chickens.
2. Treat and control swine dysentery in pigs.
Injectable form
 An injectable formulation of lincomycin is used in pigs to treat
joint infections and pneumonia.

10. Cont. …
Feed additives treatment
 It is also in medicated feed for:
1. Growth promotion and to increase feed efficiency in chickens and
pigs.
2. The treatment of pneumonia caused by Mycoplasma species in pigs.

11. Cont. …
Pirlimycin
 Pirlimycin is approved as an intra-mammary infusion for the
treatment of mastitis in lactating dairy cattle.
 It is active against sensitive organisms such as:
1. Staphylococcus aureus
2. Streptococcus agalactiae
3. Streptococcus uberis
4. Streptococcus dysgalactiae
5. Some enterococci

12. Cont. …
 Pirlimycin exhibits a post-antibiotic effect in vitro against
Staphylococcus aureus isolated from bovine mastitis, and
exposure of pathogens to subinhibitory concentrations
increases their susceptibility to phagocytosis by
polymorphonuclear leukocytes.
 Many species of anaerobic bacteria are extremely sensitive to
pirlimycin.

13. Combination
 Several combination products containing lincomycin are
approved for use in food-producing species.

14. Cont. …
Lincomycin–Spectinomycin (Lincospectin)
Poultry
 This is administered in drinking water.
 It is used for the treatment and control of respiratory disease
CRD and for improving weight gains in poultry.
Swine
 This combination is available for in-feed or drinking water for:
1. The treatment and control of enteric and respiratory disease.
2. Treatment of infectious arthritis
3. Increasing weight gain

15. Cont. …
 Injectable combination products containing lincomycin and
spectinomycin are used for:
1. Treatment of bacterial enteric and respiratory disease in pigs and
calves.
2. Treatment of arthritis in pigs.
3. Treatment of contagious foot-rot in sheep.

16. Cont. …
Lincomycin–Sulfadiazine
 This combination is administered in-feed for the treatment of
atrophic rhinitis and enzootic pneumonia in pigs.
Lincomycin–Neomycin
 This combination is used for treating acute mastitis in
lactating dairy cattle.

17. Precautions
1. Lincosamides are contraindicated in horses because of the
potential risk of serious or fatal enterocolitis and diarrhea.
– This commonly involves overgrowth of the normal microflora by non-
susceptible bacteria such as Clostridium species.
2. Oral administration of lincomycin to ruminants is
contraindicated as it has been associated with adverse side
effects such as anorexia, ketosis and diarrhea.