Corynebacterium kroppenstedtii subsp. demodicis is the endobacterium of Demodex folliculorum

Background Demodex spp. mites are the most complex member of the human skin microbiome. Mostly they are commensals, although their pathophysiological role in inflammatory dermatoses is recognized. Demodex mites cannot be cultivated in vitro, so only little is known about their life cycle, biology and physiology. Different bacterial species have been suggested to be the endobacterium of Demodex mites, including Bacillus oleronius, B. simplex, B. cereus and B. pumilus. Objectives Our aim was to find the true endobacterium of human Demodex mites. Methods The distinct genetic and phenotypic differences and similarities between the type strain and native isolates are described by DNA sequencing, PCR, MALDI‐TOF, DNA‐DNA hybridization, fatty and mycolic acid analyses, and antibiotic resistance testing. Results We report the true endobacterium of Demodex folliculorum, independent of the sampling source of mites or life stage: Corynebacterium kroppenstedtii subsp. demodicis. Conclusions We anticipate our finding to be a starting point for more in‐depth understanding of the tripartite microbe–host interaction between Demodex mites, its bacterial endosymbiont and the human host.