Cell-free supernatant of Lactobacillus salivarius SNK-6 was used in inhibition and killing studies of eight pathogenic bacterial genera in livestock and poultry
The use of microecological agents to inhibit and kill pathogenic bacteria represents a significant industrial technology with the potential to enhance animal health and ensure food hygiene.In this study,cell-free supernatant(CFS)of Lactobacillus salivarius SNK-6 was prepared by filtration and freeze-drying techniques.The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of CFS against 16 strains of zoonotic pathogens of 8 genera and 13 species were then detected in 96-well plates.The MIC and MBC of CFS against 16 strains of zoonotic pathogens of 8 genera and 13 species.The results demonstrated that the CFS of Lactobacillus salivarius SNK-6 inhibited and killed all 16 strains of zoonotic pathogens detected,but the MICs and MBCs of different strains varied considerably,with the MICs and MBCs of Gram-negative Escherichia coli and Campylobacter in the range of 1 250-2 500 mg/L;Salmonella in the range of 5 000-10 000 mg/L;MIC and MBC were 5 000 mg/L for Streptococcus chimaera;MIC and MBC were 10 000 mg/L for Klebsiella pneumoniae;MIC and MBC were 5 000 mg/L and 10 000 mg/L for the gram-positive bacteria Staphylococcus aureus;and MIC and MBC were 5 000 mg/L for Enterococcus faecium,Enterococcus faecalis,and Streptococcus suis,respectively.The study indicated that Lactobacillus salivarius SNK-6 has broad-spectrum bacteriostatic and bactericidal activities,which provide basic data for Lactobacillus salivarius SNK-6 CFS prevention and treatment of major bacterial epidemics.