SUMMARY
The article presents data on the study of genetic relatedness of S. aureus strains growing on the skin and nasal passages of patients with allergodermatoses. A study of the possible correlation between the genotype of the pathogen and the burden of allergodermatoses using the RAPD-PCR method was done.The aim of the research: determination by RAPD-PCR analysis (Random Amplified Polymorphic DNA) of genetic variability and affinity of S. aureus strains extracted from locus morbi, intact areas of skin and nasal mucosa of patients with allergodermatoses (AD and IE).Materials and methods. RAPD-PCR was used to genotype 111 strains of Staphylococcus aureus extracted from the skin and nasal passages of patients with allergodermatoses (AD and IE), as well as 11 strains isolated from the skin of almost healthy individuals to identify genetic links between these strains. These strains were removed from patients with AD and IE who sought medical help in the dermatological department of the State Institution "Institute of Dermatology and Venereology of the National Academy of Medical Sciences of Ukraine" during 2016-2019.Results. When comparing the RAPD spectra of strains extracted from the affected and intact areas of the skin of patients with mild and severe AD, the degree of genetic relatedness of the strains was 75.1±4.4 % and 98.8±0.8 %, (P?0,001), respectively, indicating a high level of affinity of the strains. Strains of S. aureus removed from the nasal passages of patients with AD had a high level of genetic affinity with strains removed from the affected areas of the skin – 79.5±1.6 %, which indicates the auto-origin of strains growing on the skin of patients. The affinity of strains isolated from patients with IE with the reference culture of S. aureus ATCC 25923 was 27.4±1.8 % and 52.0±5.2 % for strains isolated from patients with AD, indicating their low genetic relatedness.Conclusions. In the study of RAPD spectra of S. aureus strains isolated from patients with both AD and IE, no genotype was identified that would be associated with the disease or its severity. A high level of genetic affinity of strains extracted from locus morbi with strains extracted from the nasal passages of patients with AD, indicating the auto-origin of strains that grow on the skin of patients. It is shown that with increasing severity of AD, the genetic monotype of isolated pathogens increased: in patients with mild AD, 3 genetic clusters of the microorganism were identified, with moderate – 2, and with severe only one.