Commensal microflora (normal microflora, indigenous microbiota) consists of those micro-
organisms, which are present on body surfaces covered by epithelial cells and are exposed
to the external environment (gastrointestinal and respiratory tract, vagina, skin, etc.). The
number of bacteria colonising mucosal and skin surfaces exceeds the number of cells
forming human body. Commensal bacteria co-evolved with their hosts, however, under
specific conditions they are able to overcome protective host responses and exert pathologic …