Journal de bactériologie et parasitologie

Abstrait

Communities of Skin Propionic Bacteria: Cultivation and Antifungal Antagonistic Activity

Arzumanian V, Zaborova V, Globa A and Shmeleva O

Many studies concerned the propionic bacteria of human skin report just about Propionibacterium acnes, whereas it is well known that the species diversity include at least three species - P. acnes, P. granulosum and P. avidum. Recently we have used real time PCR method, which allow detecting simultaneously the three species in skin washings of healthy people.

At the first step of the study we tried to isolate pure culture of P. acnes. From 7 swabs from healthy skin propionic bacteria one was selected for cultivation, because it contained according to real time PCR only cells of P. acnes. During the cultivation of this isolate in liquid medium probes were collected and again analyzed by real time PCR. All three species of propionic bacteria were detected in each phase of cultivation. In our opinion this fact may be a reason to check the collection strains named P. acnes towards their species “purity”.

Antagonism of different propionibacteria against bacteria is well known, however so far nothing have published about their antifungal activity. The strain of Candida albicans was chosen as the test culture. Fungal cells were exposed with cell-free liquid of last stationary phase culture of propionic bacteria. About 59.4 % of alive fungal cells were killed during 2 hours when aliquot of C. albicans was combined with aliquot of bacterial cultural cell-free liquid. Propionic bacteria excreted at least two antifungal components–thermolabile and thermostabile. Small part of activity had molecular mass 3 ÷ 10 kDa, whereas the main part was contained in the fraction less than 3 kDa. Thus a new type of antagonistic activity of propionic bacteria was found out fungicidal activity, which confirm the existence of protective function of skin commensal microbiota.