Prevalence of Cutaneous Bacterial Colonization in Thai Patients with Psoriasis.

OBJECTIVE To determine bacterial colonization of skin, scalp, nares, nails, and psoriasis lesion in Thai psoriasis patients and compare findings with those of healthy controls. MATERIAL AND METHOD Sixty patients with chronic plaque-type psoriasis and 60 healthy controls of similar age and gender were enrolled. Swabs of nares, scalp, nails, and non-lesional skin were taken from all subjects. Swabs of lesional skin were taken from psoriasis patients. Aerobic bacteria were isolated from swab specimens. RESULTS Patients with psoriasis had significantly higher rate of bacteria colonization in nares, scalp, and nails than those of healthy controls. Firmicutes spp. was the most common phyla, followed by Proteobacteria spp. in both groups. Coagulase-negative staphylococci (CoNS) were the most common pathogens isolated from lesional skin, non-lesional skin, scalp, and nares of psoriasis patients. Streptococcus spp. was found only in psoriasis patients. CONCLUSION Similar to findings from Caucasian psoriasis patients, Firmicutes spp. was found to be the most common phyla colonizing the skin of Asian psoriasis patients. Streptococcus spp. was found to colonize only the skin. Further studies are needed to determine the clinical significance of streptococcal skin colonization in psoriasis patients.