An Assessment of the Presence of Clostridium tetani in the Soil and on Other Surfaces.

INTRODUCTION

Standard emergency medicine practice includes tetanus vaccine administration as part of wound care management for patients who are not fully immunized. Since there have been no available studies in the United States reaffirming the prevalence of Clostridium tetani (C tetani) since 1926, we sought to identify its prevalence in a major urban county in the US.

METHODS

We sampled soil, rusted metal, concrete, and dog feces to determine the prevalence of C tetani in a single metropolitan county in the United States. Soil samples and swabs were collected from four locations: the soil of a public park and an elementary school; dog feces from a single public dog park; and rusted surfaces (metal and concrete) in common student areas of a university campus. The presence of C tetani in each sample was determined using a quantitative polymerase chain reaction.

RESULTS

In total, 200 samples were collected, of which 37 (18.5%) tested positive for C tetani DNA. Among the 140 samples taken from the soil, just one (0.7%) tested positive for C tetani DNA. Of the 40 samples of rusted metal and concrete surfaces, 30 (75%) tested positive for C tetani, and six (30%) of the 20 samples from dog feces tested positive for C tetani.

CONCLUSION

We found that C tetani is frequently present on rusted metal and concrete surfaces but rarely in soil samples. Minor wounds contaminated with soil may be considered low risk for tetanus. However, future studies should assess the burden of C tetani in other similar urban, suburban, and rural environments to help determine the threat of C tetani more exactly.