Methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolates from skin and nares of Brazilian children with atopic dermatitis demonstrate high level of clonal diversity

Methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus produce antimicrobial substances against members of the skin microbiota in children with atopic dermatitis

Coagulase-negative Staphylococcus (CoNS) species inhibiting Staphylococcus aureus has been described in the skin of atopic dermatitis (AD) patients. This study evaluated whether Staphylococcus spp. from the skin and nares of AD and non-AD children produced antimicrobial substances (AMS). AMS production was screened by an overlay method and tested against NaOH, proteases and 30 indicator strains. Clonality was assessed by pulsed-field gel electrophoresis. Proteinaceous AMS-producers were investigated for autoimmunity by the overlay method and presence of bacteriocin genes by polymerase chain reaction. Two AMS-producers had their genome screened for AMS genes. A methicillin-resistant S. aureus (MRSA) produced proteinaceous AMS that inhibited 51.7% of the staphylococcal indicator strains, and it was active against 60% of the colonies selected from the AD child where it was isolated. On the other hand, 57 (8.8%) CoNS from the nares and skin of AD and non-AD children, most of them S. epidermidis (45.6%), reduced the growth of S. aureus and other CoNS species. Bacteriocin-related genes were detected in the genomes of AMS-producers. AMS production by CoNS inhibited S. aureus and other skin microbiota species from children with AD. Furthermore, an MRSA colonizing a child with AD produced AMS, reinforcing its contribution to dysbiosis and disease severity.

Atopic dermatitis pediatric patients show high rates of nasal and intestinal colonization by methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci

BACKGROUND

Atopic dermatitis (AD) patients have high rates of colonization by Staphylococcus aureus, which has been associated with worsening of the disease. This study characterized Staphylococcus spp isolates recovered from nares and feces of pediatric patients with AD in relation to antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec) type, presence of pvl genes and clonality. Besides, gut bacterial community profiles were compared with those of children without AD.

RESULTS

All 55 AD patients evaluated had colonization by Staphylococcus spp. Fifty-three (96.4%) patients had colonization in both clinical sites, whereas one patient each was not colonize in the nares or gut. Staphylococcus aureus was identified in the nostrils and feces of 45 (81.8%) and 39 (70.9%) patients, respectively. Methicillin-resistant Staphylococcus spp. isolates were found in 70.9% of the patients, and 24 (43.6%) had methicillin-resistant S. aureus (MRSA). S. aureus (55.6%) and S. epidermidis (26.5%) were the major species found. The prevalent lineages of S. aureus were USA800/SCCmecIV (47.6%) and USA1100/SCCmecIV (21.4%), and 61.9% of the evaluated patients had the same genotype in both sites. Additionally, gut bacterial profile of AD patients exhibits greater dissimilarity from the control group than it does among varying severities of AD.

CONCLUSIONS

High rates of nasal and intestinal colonization by S. aureus and methicillin-resistant staphylococci isolates were found in AD patients. Besides, gut bacterial profiles of AD patients were distinctly different from those of the control group, emphasizing the importance of monitoring S. aureus colonization and gut microbiome composition in AD patients.

Therapeutic potential of ozone water treatment in alleviating atopic dermatitis symptoms in mouse models: Exploring its bactericidal and direct anti-inflammatory properties

Currently, ozone water is utilized for antibacterial and antiviral purposes without any reported safety concerns. Therefore, ozone water may have clinical applications in treating staphylococcal-specific cutaneous diseases, such as atopic dermatitis (AD) and pyoderma. This study aimed to verify the bactericidal effects of ozone water at different concentrations (3 and 11 mg/L) against staphylococcal species in vitro, as well as evaluate the anti-inflammatory effects of ozone water in a mouse model of AD and pyoderma. Initially, the bactericidal properties of several concentrations of ozone water were confirmed with Staphylococcus aureus and methicillin-resistant S. pseudintermedius. Both 3 and 11 mg/L of ozone water exhibited a significant bactericidal effect against staphylococci at less than 100 times dilution. We next examined the cellular cytotoxicity and cytokine production (Interleukin (IL)-6 and IL-8) induced by S. pseudintermedius pre-treated with ozone water, and our findings indicated that cytotoxicity and cytokine production induced by staphylococci were significantly inhibited after ozone water pre-treatment. In vivo experiments showed that ozone water-pre-treated S. pseudintermedius significantly inhibited the development of pyoderma in mice; however, limited effects were observed in a therapeutic setting. Interestingly, ozone water at concentrations of 3 and 11 mg/L exhibits dual bactericidal and anti-inflammatory effects in mice with AD. This observation was corroborated by the significant inhibition of cytokine production in interferon-γ/tumor necrosis factor-stimulated human epidermal keratinocyte cells exposed to ozone in vitro. These findings indicate that administering ozone can be a novel therapeutic approach for managing allergic skin diseases, such as AD.