Search for environmentally friendly bacteria for use as tick biocontrol agents

While ticks are obligate blood feeders, they spend over 90% of their life off-host, and it is during this critical time that they can directly uptake water from the environment. The importance of this drinking behavior was reflected in our previous characterization of the microbiome of field-collected Amblyomma americanum, which showed that the tick midgut contains bacterial taxa with typical soil members, likely acquired from the environment. However, it is well known that the microbial environment in the tick gut is low in bacterial diversity and abundance compared to other blood-feeding arthropods, such as mosquitoes. Nevertheless, our previous microbiome studies have shown a high abundance of culturable Bacillus spp. and Pseudomonas spp, in addition to bacterial taxa containing typical soil microbe members.

Furthermore, studies have demonstrated the toxicity of Bacillus thuringiensis (Bt) to other tick species. Our preliminary screening feeding live bacterial cells of Bt. Kurstaki demonstrated 60% mortality after eight days of feeding, thus suggesting the potential for being developed as a novel biopesticide against ticks. In addition, other bacterial strains induced 100% mortality in a short time frame.

We aim to identify novel, environmentally friendly Bacillus spp., Pseudomonas, and spore-forming bacterial strains that cause tick mortality and can potentially be used as tick biopesticides. In addition, we aim to study the anatomical changes in the gut structure during bacterial invasion to elucidate the potential mode of action and further understand tick vector competence to develop strategies for tick disease mitigation.