Comparative study on Salmonella isolation from sewage—contaminated natural waters

Abstract
A comparative study of 5 factors influencing the isolation of salmonellas from sewage-contaminated natural waters was carried out. The effect of pre-enrichment in buffered peptone water was compared with single-step enrichment in NR10 broth incubated at 43.degree. C. A modification of NR10 was compared with the original composition. Bismuth sulfite agar (BSA), Hektoen enteric agar (HE) and brilliant green agar (BGA) were used as plating media. Other factors considered were temperature of the water and sampling site. A total of 759 salmonella strains belonging to 36 different serotypes were recovered in a 2 yr study. All 5 factors considered in the study showed a significant effect on the recovery of salmonellas. The combination of direct enrichment in NR10, followed by BSA or HE as plating media was most effective for the isolation of Salmonella. The influence of water temperature and characteristics of the sampling sites were also discussed.