Age- and Sex-Linked Bacterial Community Variation and Function Prediction from Insoles of Healthy Chinese Population

Sweat secretion keeps feet and insoles humid and rich in nutrients, which are the conditions needed to maintain abundant microbial growth. Analyzing the diversity and function of microorganisms in the insole is of great significance in the development of functional insoles and prediction of human foot hygiene condition. In this study, pure culture method, MiSeq high-throughput sequencing technology, and PICRUSt gene function prediction were used to analyze the diversity and function of the bacterial community from insoles of healthy population of different sexes and age groups. Staphylococcus, Micrococcus, and Brevibacterium are present in all insole samples, and there is no significant difference between sexes of the same age group. However, a significant difference in insole microbial population was obtained among age groups. For community function, all six samples expressed similarity in the preliminary metabolism, but in samples from the elderly, many specific catabolic genes were associated with human disease and drug resistance. This study provides a reference for the development of multi-function insoles and other sanitary products for disease prediction in a healthy population.