Normal microflora of the pharyngeal mucosa

: Aerobic microflora of the throat mucosa was studied in 518 healthy persons aged 1 to 50 years. On the basis of the study results, criteria for estimating microbiocenoses of the upper respiratory tracts were defined. It was shown that the throat symbiotic flora included three groups of microorganisms playing different roles in the development of microbiocenosis. The indigenous group consisted of representatives of Streptococcus and Neisseria and was characterized by permanent (90-100 per cent) and intensive (3-8 lg CFU/ml) colonization, broad species spectrum, associations of 2-3 and more species and no significant influence of sociological, age and season factors. The representatives of the facultative group i.e. bacteria belonging to Staphylococcus, Corynebacterium and Haemophilus were less frequent (25-50 per cent). The intensity of their isolation was lower (1-4 lg CFU/ml) and their species spectrum was narrow. The microorganisms of the transitory group were characterized by low frequency (5-20 per cent) and insignificant contamination of the throat mucosa (1-2 lg CFU/ml). The nature of the colonization was monospecific. The group was more numerous by generic composition (Candida, Escherichia, Klebsiella, Citrobacter, Enterobacter, Pseudomonas, Branhamella, Moraxella and Micrococcus). However, it was generally limited by one colonization type. The facultative and transitory groups were subject to age and season variation. They were also different in urban and rural populations.