Prevalence and Fate of Gut-Associated Human Pathogens in the Environment

Abstract

This chapter examines the available information concerning prevalence, survival, and, ultimately, fate of enteric bacterial pathogens in different environments and under various conditions. The bacterial pathogens discussed in this chapter are those known to have a water-based or water-mediated transmission route between the environment and humans. Animal contamination, especially by bird flocks, is believed to be a primary source of campylobacters in remote water environments and Campylobacter jejuni has been consistently isolated from wild bird populations. Sand in particular appears capable of supporting significant populations of enterococci, especially when compared to water. It is clear that enterococci are capable of multiplication under simulated environmental conditions; however, whether these types of conditions are ever naturally present in the environment is debatable. Studies suggest that Salmonella is capable of surviving for extended periods in the environment, especially within soil and livestock waste. The presence of bacteria in the environment is essentially dependent on two factors: loading and survival. Pathogenic Vibrio spp. are also clearly capable of persistence and growth within the aquatic environment. Many of the studies examining characteristics of enteric pathogens in the environment have focused on the presence of these organisms in aquatic environments and water supplies, perhaps because this is viewed as the most likely vector for human infection. Recent studies have presented novel, molecular-based approaches to detection or quantification of certain enteric pathogens.