Evaluation of the secretion of antimicrobial peptides and antimicrobial effect of skin wash in atopic and healthy dogs: a preliminary study.

Background: Antimicrobial peptides (AMPs) are an important component of cutaneous innate immunity. The amount of AMPs secreted in healthy and atopic patients is controversial.

Hypotheses/objectives: To evaluate the antimicrobial effect of skin wash harvested from healthy and atopic dogs, the amount of AMPs (cBD3-like/cBD122, cCath, S100A8/9/12) present in the skin washes, and the correlation between AMP levels and severity of the clinical signs.

Animals: Fifteen healthy and 15 mildly atopic, privately owned dogs.

Methods And Materials: Skin washes were performed on a 15 cm area of nonlesional abdominal skin. The area was rinsed with 2.7 mL of saline using a sterile tube. Commercially available (S100A8/9/12) or in-house (cBD3-like and cCath) canine-specific ELISAs were performed. Skin washes were incubated with different concentrations (5 × 10 to 4 × 10 cfu/mL) of Staphylococcus pseudintermedius and the bacterial density measured after 24 h of incubation. Severity of clinical signs was assessed by the Canine Atopic Dermatitis Extent and Severity Index, 4 version (CADESI-04). Data were analysed statistically and significance level was set as P ≤ 0.05.

Results: There was no significant difference in any of the tested AMPs between healthy and atopic dogs. Strong/moderate positive correlations were seen between total and inguinal CADESI-04 (r = 0.69; P = 0.0061) and between AMPs [cBD3-like/cCath (r = 0.69; P = 0.011), S100A8/S100A9 (r = 0.8; P = 0.0016) and S100A9/S100A12 (r = 0.57; P = 0.047)]. Significantly less antimicrobial activity was seen in skin washes from atopic versus healthy dogs (P < 0.05).

Conclusions And Clinical Importance: This study found no difference in AMP secretion levels between healthy and nonlesional atopic canine skin. However, a significantly lower antimicrobial activity was present in the skin washes from atopic compared to healthy skin.