Traceability of Geographic Origin Using Human Skin and Oral Microbiota / 法医学杂志

OBJECTIVES@#To explore the possibility of using human skin and oral microorganisms to estimate the geographic origin of an individual through the sequencing analysis of bacterial 16S rRNA gene.@*METHODS@#Microbial DNA was extracted from the palm and oral microorganisms of the Han population in Shanghai and Chifeng, Inner Mongolia, and the composition and diversity of the microbiota were analyzed by full-length 16S rRNA gene sequencing. Then, differential species were screened and a geographic location prediction model was constructed.@*RESULTS@#The compositions of palm and oral microorganisms between Shanghai and Chifeng samples were both different. The abundance and uniformity of palm side skin microorganisms were higher in Chifeng samples than in Shanghai samples, while there was no significant difference in oral microorganisms. Permutational multivariate analysis of variance (PERMANOVA) confirmed that th e β -diversity between the samples from the two places were statistically significant, and the coefficients of determination (R2) for skin and oral samples were 0.129 and 0.102, respectively. Through principal co-ordinates analysis (PCoA), the samples from the two places could be preliminarily distinguished. The predictive model had the accuracies of 0.90 and 0.83 for the geographic origin using the skin and oral samples, respectively.@*CONCLUSIONS@#There are differences in the compositions of palm and oral microbiota between Han populations in Shanghai and Chifeng. The prediction model constructed by the random forest algorithm can trace the unknown individuals from the above two places.

Antimicrobial effect of Malaysian green tea leaves (Camellia sinensis) on the skin microbiota

Aims: Camellia sinensis ( green t ea) is known for its therapeutic properties (anti - inflammatory, anti - oxidative and anti - ageing). The aim of this study was to determine the in vitro inhibitory activity of gree n tea extract on some odorous skin commensal bacteria. Methodology and results: Tea leaves were collected from MARDI Agro Technology Park, Cameron Highlands. A standardised protocol was used to obtain green tea extract. Aqueous green tea extracts were tes ted for antibacterial activity by well diffusion method. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) assays were performed by broth microdilution assays using green tea extract concen trations from 16 to 0.0313 mg/ mL . Green tea extract showed antibacterial activity against skin microbiota. The high antimicrobial effect was achieved against Micrococcus luteus with MIC and MBC of 0.125 and 0.25 mg/μL respectively, followed by Staphylococcus epidermidis with MIC and MBC o f 0.25 and 0.25 mg/μL respectively, Bacillus subtilis with MIC and MBC of 0.5 and 0.5 mg/μL respectively and lastly, Corynebacterium xerosis with MIC and MBC of 0.5 and 1.0 mg/μL respectively. Conclusion, significance and impact of study: The results obta ined from the study confirm the in vitro anti - microbial activity of green tea extracts against skin microbiota. The antibacterial effects of green tea against skin bacteria with its anti - oxidant and anti - aging properties will help in keeping skin healthy, fresh and reducing unpleasant odo rs .