The effect of Streptomyces species on the survival of Salmonella in soil

Abstract A modified Chelex 100 ion-exchange extraction method was used to monitor streptomycete spores, streptomycete mycelia and Salmonella in soil. Salmonella dusseldorf in soil was inhibited by the bactericidal effect of streptomycin and by the growth of Streptomyces bikiniensis . The soil used in the experiments exerted an antimicrobial effect on S. dusseldorf .
Competition between S. dusseldorf, Streptomyces lividans TK24 and Stm. bikiniensis ATCC 11062 was monitored in soil. In sterile amended soil Stm. lividans increased the survival of S. dusseldorf , whereas survival was reduced in the presence of the known streptomycin producer, Stm. bikiniensis . In the presence of S. dusseldorf the production of spores and mycelia by Stm. bikiniensis was reduced, and Stm. lividans sporulation was reduced but mycelia production increased. Evidence was seen for a beneficial effect between S. dusseldorf and Stm. lividans mycelia.
In non-sterile unamended soil the survival of S. dusseldorf was increased in the presence of Stm. lividans , whereas Stm. bikiniensis had no effect. Stm. lividans and Stm. bikiniensis reduced the survival of S. dusseldorf in non-sterile amended soil, with the most dramatic reduction caused by Stm. bikiniensis . No such changes in the survival of S. dusseldorf were observed with non-sterile amended soil that had been treated with sludge. The presence of sludge in unamended soil increased the rate of Salmonella die-off. In unamended soil containing sludge the presence of Stm. lividans increased the survival of S. dusseldorf , whereas survival was reduced in the presence of Stm. bikiniensis . The data provided evidence of antibiosis in soil, relating to the possible production of streptomycin by Stm. bikiniensis .