Features of the microbial landscape of the skin of patients with atopic dermatitis during exacerbation and in the remission phase

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases that significantly reduces the quality of life and creates a significant burden on the healthcare system. One of the key factors in the unstable course of AD is skin dysbiosis: during the exacerbation period, the diversity of commensals decreases and the proportion of potentially pathogenic microorganisms, primarily Staphylococcus aureus, increases. The aim of the study. To study the infectious landscape of the skin of patients with atopic dermatitis in the periods of exacerbation and remission in comparison with the features of the microbial profile of blood (according to mass spectrometry) in the phase of exacerbation and remission of the disease. Material and methods. 46 patients (28 women, 18 men, mean age 23±3.4 years) with moderate-severe course of AD and frequent exacerbations (≥3 episodes per year) were examined. The severity was assessed by the SCORAD index. The skin microbiota was studied by growing it on blood agar, universal chromogenic media, and Saburo agar; the blood was analyzed by mass spectrometry according to the laboratory protocol. Results. In the exacerbation phase, Escherichia coli (7±0.83×107), Staphylococcus aureus (6±0.76×106), Staphylococcus epidermidis (10±0.95×107), Streptococcus pyogenes (3±0.57×103), and Candida albicans (5±0.68×105) were detected on the skin. In the blood during the same period, elevated indicators corresponding to the equivalent microflora were recorded, as well as an increase in the content of markers of the herpes simplex group viruses (herpes simplex virus types 1 and 2 (HSV-1/2) and cytomegalovirus — CMV). During the remission period, saprophytic forms of staphylococci prevailed on the skin, and the levels of herpesviruses did not exceed the reference values. These findings confirm the clinical significance of the infectious factor as one of the leading triggers of AD exacerbations and indicate the potential contribution of microorganisms that are less commonly considered as triggers (such as E. coli), as well as herpesviruses that can support inflammation and exacerbate itching. These results should be taken into account when selecting comprehensive AD treatment that follows the principles of rational antimicrobial use. Conclusion. In atopic dermatitis, comprehensive patient management is necessary, which means that the infectious factor is considered as one of the important triggers for exacerbations, and the correction of the microbiota and the use of antimicrobial agents are carried out rationally, taking into account the clinical signs of infection and current recommendations. The detection of species that are not typical for the skin microbiome, such as Escherichia coli, as well as the possible contribution of herpesviruses, should be taken into account in the diagnosis and individualization of preventive measures.