A new study offers insight into the over time.
The research “suggests that different CC types might harbor different virulence factors and that the patient’s immune system needs to adjust to this,” concluded the authors of the study, published in the British Journal of Dermatology.
There is a strong association between disease severity and colonization with S. aureus in patients with AD, and as many as 90% are colonized with the microbe but, the authors pointed out, it’s not entirely clear how S. aureus affects the development of AD.
They added that there’s been little research into the possible effects of changes in S. aureus clonal types over time. Still, “new studies indicate that specific clonal types could be linked to specific host phenotypes, illustrating that host-microbe interactions might be important for colonization of AD skin,” they said.
The authors, led by Maja-Lisa Clausen, MD, of the department of dermatology at the University of Copenhagen, tracked 63 adult patients with AD at Denmark’s Bispebjerg Hospital from 2013-2015 to a 2016-2017 follow-up period. Their mean age was 36 years.
They analyzed bacterial swabs taken from the nose, lesional skin, and nonlesional skin. Of the 63 participants, 47 (75%) were colonized with S. aureus in at least one location when the study began, and 27 of those (57%) were still colonized at follow-up. Of the 16 patients not colonized at baseline, 7 patients (44%) had become colonized by follow-up.
Of the 27 patients who were colonized at both time points, 14 (52%) had no change in CC type.
Those who were colonized at follow-up in at least one of the three sites sampled had more severe disease, with a mean SCORAD – or disease severity score – of 37, compared with those who were not colonized at that time, with a mean SCORAD of 28 (P = .067).
There was a much bigger gap in mean SCORAD score between the 14 patients who had the same CC type at both baseline and follow-up (a mean score of 30), compared with the 11 patients with different CC types at follow-up (a mean score of 47), a statistically significant difference (P = .03). Mean severity scores went up in those who changed CC types and down in those whose CC types remained the same.
The findings “illustrate that colonization changes over time, and also probably reflect the relapsing course of this disease, as colonization likely occurs in relation to worsening of the eczema,” the study authors wrote. They cautioned that “other factors should be taken into considerations as these are known to influence AD severity, including change in treatment regimens, climate, or other disease.”
Novo Nordisk Foundation funded the study. No relevant disclosures were reported.
SOURCE: Clausen, ML et al. Br J Dermatol. 2018 Aug 2. doi: 10.1111/bjd.17033.