Conference paper

Decrease in the number of bacteria for nucleic acid extraction and sampling of microbiome from the environment

22 Nov 2016


Purpose / Context

Public facilities such as homes for aged individuals and schools are considered at an increased risk for the spread of infections. To our knowledge, there has been no research on the relationship between the microbiome and human activity at such places. Therefore, we investigated the microbiome of locations housing individuals with weakened immune systems due to the spread of infection, to reveal its characteristics. We attempted to establish a method to sample microbiomes from these environments.


For ease of sampling, we used Lactobacillus instead of the microbiome directly. We dropped the diluted Lactobacillus onto a plate and swabbed it. After DNA extraction from these bacteria, we calculated the number of bacteria by real-time PCR analysis.


Results showed that approximately 50% of bacteria were lost during sampling and nucleic acid extraction. In this experiment, we found a faint band for the negative control by gel electrophoresis. Prevention and control of microbial contamination are required in the future.

Key Findings

Slightly fewer than 50% of initial bacteria were scattered in the air or deposited on the plate, even considering the number of bacteria after wiping.


Identification of bacteria directly and rapid analysis.