Characterization of acne patients carrying clindamycin-resistant Cutibacterium acnes: A Japanese multicenter study.

Use of antimicrobials for acne treatment is correlated with an increased occurrence of antimicrobial-resistant Cutibacterium acnes. To clarify the role of antimicrobial use on the resistance and to investigate the characteristics of resistant strains, we conducted a multicenter study in dermatological clinics frequently visited by new patients with acne vulgaris. We collected specimens in 264 acne patients and tested 164 C. acnes strains isolated from 164 patients visiting 13 dermatological clinics. Antimicrobial susceptibility testing showed that the rates of resistance for tetracyclines, macrolides and clindamycin were significantly higher in C. acnes strains isolated from patients using antimicrobials for acne treatment than patients not using them. In particular, clindamycin-resistant strains were frequently isolated from patients with older median age (≥24 years) and severe/moderate acne. After investigating the resistance mechanism of 15 high-level clindamycin-resistant strains, the transposable clindamycin resistance genes, erm(X) or erm(50), were detected in 14 strains. Using single-locus sequence typing for C. acnes, the strains with erm(X) or multidrug resistance plasmid pTZC1 coding erm(50) and tetracycline resistance gene tet(W) were classified into clade F, which were specifically isolated from Japanese patients with acne, except for one strain. Our data showed that patients' information, such as antimicrobial use, age and acne severity, are valuable in estimating whether a patient carries antimicrobial-resistant C. acnes. Additionally, our results suggest that the clade F strains have a high risk of acquiring multidrug resistance.

Analysis of All 34 Exons of the SPINK5 Gene in Japanese Atopic Dermatitis Patients.

Lympho-epithelial Kazal-type-related inhibitor (LEKTI) is a large multidomain serine protease inhibitor that is expressed in epidermal keratinocytes. Nonsense mutations of the SPINK5 gene, which codes for LEKTI, cause Netherton syndrome, which is characterized by hair abnormality, ichthyosis, and atopy. A single nucleotide polymorphism (SNP) of SPINK5, p.K420E, is reported to be associated with the pathogenesis of atopic dermatitis (AD). We studied all 34 exons of the SPINK5 gene in Japanese 57 AD patients and 50 normal healthy controls. We detected nine nonsynonymous variants, including p.K420E; these variants had already been registered in the SNP database. Among them, p.R654H (n=1) was found as a heterozygous mutation in the AD patients, but not in the control. No new mutation was detected. We next compared the data of the AD patients with data from the Human Genetic Variation Database provided by Kyoto University; a significant difference was found in the frequency of the p.S368N genotype distribution. PolyPhen-2 and SIFT, two algorithms for predicting the functional effects of amino acid substitutions, showed significant scores for p.R654H. Therefore, R654H might be a risk factor for epidermal barrier dysfunction in some Japanese AD patients.

Actions of gluco-oligosaccharide against Staphylococcus aureus.

Heavy colonization of atopic dermatitis (AD) with Staphylococcus aureus is well documented. The purpose of the present study is to examine the actions of gluco-oligosaccharide (G-OS) against S. aureus for the control of AD skin lesions infected with S. aureus. The colony counts of S. aureus cells in 0.5% sodium chloride solution supplemented with 5% G-OS (pH 4.8) were about 10-fold lower than those in 0.5% sodium chloride solution (pH 6.6; control) after incubation for 24 hours. The colony counts of S. aureus cells attached on the coverslips (pre-treatment with 1% and 5% G-OS/PBS and following treatment with plasma) were about 10-fold lower than those on the coverslips (pre-treatment with PBS and following treatment with plasma; control) in PBS after incubation for 24 hours. The materials (sugars, probably glycocalyx) that stained positively for fluorescein-isothiocyanate (FITC) -concanavalin A and were consistent with the presence of S. aureus cells were reduced when S. aureus cells attached to the coverslips treated with 5% GC-OS. In conclusion, C-OS is a promising agent that can be applied topically in a cream to clear adherent S. aureus cells from skin lesions of AD in order to prevent its exacerbation. Further, 5% C-OS can inhibit glycocalyx production by S. aureus cells and consequently have some suppressive effect on the colonization of S. aureus on the horny cells of AD lesions.

Dynamic alteration of human beta-defensin 2 localization from cytoplasm to intercellular space in psoriatic skin.

Defensins are cationic antimicrobial peptides with a broad spectrum. Recently human beta-defensin 2 (hBD-2) has been isolated from psoriatic skin; however, its exact localization and fate have not been fully understood. We studied the distribution pattern of hBD-2 in skin tissues of psoriasis and other inflammatory skin diseases. In the upper spinous and granular layer of psoriasis vulgaris hBD-2 was present in the cytoplasm. In the horny layer the positive signals were in a basket-weave pattern, indicating possible accumulation of hBD-2 in the intercellular space. The similar pattern of hBD-2 distribution was observed in the lesions of nummular eczema and atopic dermatitis. hBD-2 was not detected in the section of normal elbow and knee skin. When isolated psoriatic scales were stained, hBD-2 was detected in a wrapping paper-like distribution pattern surrounding the corneocytes. In horny layer of psoriatic skin hBD-2 was closely associated or colocalized with elafin, which is known to be in extracellular space, as demonstrated by double staining. Western blot analysis using cultured human keratinocytes detected hBD-2 with an expected size in the conditioned medium and in the cell lysates when stimulated with 5% FCS or IL-alpha. These results indicate that hBD-2 was synthesized and remained in cytoplasm in the upper spinous and granular layer, and then secreted into intercellular space in the horny layer. This dynamic change in hBD-2 distribution in epidermis is certainly relevant to function as an innate host defense mechanism against invading micro-organisms.

Effects of human neutrophil peptide-1 on the expression of interstitial collagenase and type I collagen in human dermal fibroblasts.

Human neutrophil peptide-1 (HNP-1), a defensin with antimicrobial properties, is also thought to promote wound healing. To elucidate the mechanism by which wound healing is facilitated by this factor, we investigated the effect of HNP-1 on the expression of interstitial collagenase (matrix metalloproteinase 1, MMP-1), collagen types I and III, and tissue inhibitor of metalloproteinase 1 (TIMP-1) by cultured fibroblasts by means of RT-PCR and ELISA. Our results showed that synthetic HNP-1 increased the expression of proalpha1(I) collagen mRNA and protein. In contrast, the expression of MMP-1 was decreased at both the mRNA and protein levels. Our observations suggest that HNP-1 may promote wound repair by enhancing extracellular matrix deposition and by controlling its degradation.