Identification and antibioticresistance of lactic acid bacteria isolated from the gastrointestinal tract of a rabbit

Abstract

The probiotic preparations, used in rabbit breeding, contain bacteria, isolated from various econiches. Therefore, these drugs are universal and recommended for different types of animals. One of the ways to increase the effectiveness of probiotics, used in breeding rabbits is the selection of strains of biologically active representatives of the obligate microflora of the gastrointestinal tract of these animals.Purpose. Identify lactic acid bacteria, isolated from the gastrointestinal tract of a rabbit, promising for the creation of probiotic preparations. Investigate antibiotic resistance of the most biologically active isolates.Methods. The identification of lactic acid bacteria to the genus Lactobacillus was carried out according to generally accepted methods. Molecular genetic identification was performed using a polymerase chain reaction. For the most promising strains, the sensitivity to antibiotics was studied using the disco-diffusion method and the minimum inhibitory concentration of antibiotics, which completely retarded the growth of bacteria.Results. 250 bacterial isolates, isolated from the gastrointestinal tract of rabbits were identified to the Lactobacillus genus, 10 most active of which were selected for the further work. It has been established, that 40% of selected isolates of lactic acid bacteria are capable of fermenting arabinose, dulcite; 50% beckoning; 70% sorbitol; 80% - mannose, fructose; 90% - lactose; 100% - galactose, maltose, sucrase, glucose; 20% - raffinose. Molecular genetic studies have established that the isolate Lactobacillus sp. 13/2 does not have genes typical for L. acidophilus and L. helveticus species. It has been found, that the lowest value of the minimum inhibitory concentration of antibiotics of the studied isolates was revealed to prolonged-action penicillins, which act bactericidally, disrupting the synthesis of the bacterial cell wall. The highest is for ampicillin, which is active against gram-positive bacteria that are affected by benzylpenicillin. The results indicate the absence of acquired antibiotic resistance. However, isolate L-13/2 showed resistance to oxacillin, kanamycin, streptomycin, nalidixic acid.Findings. According to a complex of morphological, cultural, and physiological and biochemical properties, the ten most active isolates of lactic acid bacteria, isolated from the gastrointestinal tract of rabbits, of 250 ones are previously assigned to phylogenetic groups: L. acidophilus, L. lactis, L. casei, L. plantarum. For use the selected isolate Lactobacillus sp. 13/2 as a basis for the probiotic preparation, it is necessary to use additional identification methods to determine the species.It has been established, that the studied isolates as a whole did not exhibit antibiotic resistance. Perspective isolate Lactobacillus sp. 13/2 was resistant to some antibiotics. Therefore, there is a need to study in greater detail the antibiotic resistance of the isolate under study in order to exclude the possibility of horizontal transfer of resistance genes