Influence of soil microbes on Escherichia coli O157:H7 survival in soil rinse and artificial soil

Aims: This research investigated the influence of soil microbiota on Escherichia coli O157:H7 survival in soil rinse and artificial soil. Additionally, the influence of selected soil bacteria on E. coli O157:H7 in soil environments was determined. Methods and Results: Escherichia coli O157:H7 counts (log CFU per ml or g(-1)) were determined by spread plating: (i) artificial soil amended with soil rinse (filter-sterilized and unfiltered) at 30 degrees C; (ii) unfiltered soil rinse (50 ml) treated with cycloheximide (200 mu g ml(-1)), vancomycin (40 mu g ml(-1)), heat (80 degrees C, 15 min) and no treatment (control) for 7 days at 30 degrees C and (iii) filtered soil rinse with selected soil bacterial isolates over 7 days. There was a significant difference (P = 0.027) in E. coli O157:H7 counts after 35 days between artificial soils amended with filtered (4.45 +/- 0.29) and non-filtered (1.83 +/- 0.33) soil rinse. There were significant differences (P < 0.05) in E. coli O157:H7 counts after 3 days of incubation between soil rinse treatments (heat (7.04 +/- 0.03), cycloheximide (6.94 +/- 0.05), vancomycin (4.26 +/- 0.98) and control (5.00 +/- 0.93)). Lastly, a significant difference (P < 0.05) in E. coli O157:H7 counts was observed after 3 days of incubation at 30 degrees C in filtered soil rinse when incubated with Paenibacillus alvei versus other soil bacterial isolates evaluated. Conclusions: Soil microbiota isolated from Florida sandy soil influenced E. coli O157:H7 survival. Specifically, P. alvei reduced E. coli O157:H7 by over 3 log CFU per ml after 3 days of incubation at 30 degrees C in filtered soil rinse. Significance and Impact of the Study: This research identified soil bacterial isolates that may reduce E. coli O157:H7 in the soil environment and be used in future biocontrol applications.

Automated summary

The research investigated the influence of soil microbiota on Escherichia coli O157:H7 survival and identified soil bacterial isolates, particularly P. alvei, that may reduce E. coli O157:H7 in the soil environment and be used in future biocontrol applications.