Susceptibility of poultry lactobacilli to ionophore antibiotics.
The susceptibility of four poultry Lactobacillus strains to monensin, narasin, lasalocid, salinomycin and maduramicin was investigated using two different systems of lactobacilli cultivation. In the MRS broth (Oxoid) with glucose, the growth of lactobacilli was inhibited at ionophore concentrations as low as 0.4-5 microgram/ml. On the other hand, the growth of lactobacilli in the mixture of a commercial concentrate with water (1:2) was not influenced by ionophores at 100 micrograms/g. It follows from these results that lactobacilli are much more resistant to ionophores in their natural environment than in laboratory cultures on glucose. It was concluded that: probiotic lactobacilli can be added to ionophore-containing concentrates; antibiotic susceptibility data obtained in liquid cultures with glucose are misleading.
Marounek
M
M
Institute of Animal Physiology and Genetics, Prague, Czech Republic.
Rada
V
V
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003470:Culture Media / Q000737:chemistry; D007476:Ionophores / Q000494:pharmacology*; D007778:Lactobacillus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D011200:Poultry / Q000382:microbiology*
D000900:Anti-Bacterial Agents; D003470:Culture Media; D007476:Ionophores