Surface sterilization methods impact measures of internal microbial diversity in ticks

Area of Science:

• Microbiology
• Entomology
• Genomics

Background:

• Ticks transmit pathogens globally, making their internal microbiome crucial for understanding disease transmission.
• Research on tick symbionts requires effective surface sterilization to isolate internal microbes.
• Existing methods like ethanol and bleach have varying impacts on microbial DNA.

Purpose of the Study:

• To compare the efficacy of bleach and ethanol sterilization methods.
• To assess their impact on the measured internal microbial diversity of ticks.
• To determine the optimal method for studying tick internal microbiomes.

Main Methods:

• Comparing bacterial diversity in Cayenne ticks (Amblyomma cajennense) sterilized with 1% bleach versus 70% ethanol.
• Utilizing 16S rRNA gene sequencing for bacterial barcoding.
• Analyzing external microbiomes from tick cuticles and washing water.

Main Results:

• Ethanol treatment resulted in higher detected bacterial diversity than bleach treatment.
• Bleach effectively eliminated external bacterial DNA, while ethanol did not.
• Ethanol-treated ticks showed contamination from external bacteria.

Conclusions:

• Bleach sterilization is the gold standard for removing external bacterial DNA from ticks.
• Bleach preserves internal microbial diversity, unlike ethanol-based methods.
• Accurate internal microbiome studies necessitate bleach for surface sterilization.