[Heterogeneity in phage sensitivity in populations of S. aureus vegetating in patients and carriers]

It was found that the S. aureus populations vegetating in patients and carriers were heterogeneous by phagegroup reference of the strains isolated in 31.1 and 23.9% of cases, respectively, and in 35.9 and 26.9%--phagovars. The frequency and the extent of variability of the populations in the patients depended on the character of the disease, the site of infection and the association of the focus with the external environment, and in carriers--on the localization and the carrier category. S. aureus populations habituating in the patients with the primary purulent processes and mastitis, as in the closed processes and in cases of extrahospital infection consisted, with rare exception, of the strains of one phagovar. In a considerable number of patients with purulent processes after the incision (38.0%), with infected wounds (37.2%), and particularly with burns (78.6%) of the S. aureus population consisted of 2, 3 and even 4 phagovars. Variable were also populations vegetating in patients with open processes (47.1%) and in hospital (26.5%) and mixed infection (52.6%). The phage-type composition of the S. aureus populations in carriers was also characterized by heterogeneity, which was more pronounced in chronic carriers and in case of localization of the processes in the nose. On the basis of the data obtained the minimal number of cultures which should be studied from the microbial focus in order to obtain objective data on the composition of phagovars in the population of various categories of patients and carriers was calculated.