High prevalence of methicillin resistance and PVL genes among Staphylococcus aureus isolates from the nares and skin lesions of pediatric patients with atopic dermatitis

Abstract

Staphylococcus aureus is highly prevalent among patients with atopic dermatitis (AD), and this pathogen may trigger and aggravate AD lesions. The aim of this study was to determine the prevalence of S. aureus in the nares of pediatric subjects and verify the phenotypic and molecular characteristics of the isolates in pediatric patients with AD. Isolates were tested for antimicrobial susceptibility, SCCmectyping, and Panton-Valentine Leukocidin (PVL) genes. Lineages were determined by pulsed-field gel electrophoresis and multilocus sequence typing (MLST). AD severity was assessed with the Scoring Atopic Dermatitis (SCORAD) index. Among 106 patients, 90 (85%) presented S. aureus isolates in their nares, and 8 also presented the pathogen in their skin infections. Two patients had two positive lesions, making a total of 10 S. aureusisolates from skin infections. Methicillin-resistant S. aureus(MRSA) was detected in 24 (26.6%) patients, and PVL genes were identified in 21 (23.3%), including 6 (75%) of the 8 patients with skin lesions but mainly in patients with severe and moderate SCORAD values (P=0.0095). All 24 MRSA isolates were susceptible to trimethoprim/sulfamethoxazole, while 8 isolates had a minimum inhibitory concentration (MIC) to mupirocin >1024 μg/mL. High lineage diversity was found among the isolates including USA1100/ST30, USA400/ST1, USA800/ST5, ST83, ST188, ST718, ST1635, and ST2791. There was a high prevalence of MRSA and PVL genes among the isolates recovered in this study. PVL genes were found mostly among patients with severe and moderate SCORAD values. These findings can help clinicians improve the therapies and strategies for the management of pediatric patients with AD.

Molecular characterization of Staphylococcus aureus isolates carrying the Panton-Valentine leukocidin genes from Rio de Janeiro hospitals

“…This lineage carrier of PVL genes had already been reported in Argentina (Egea et al, 2014;Fernandez et al, 2012) and in Brazil (Cavalcante et al, 2015;Caboclo et al, 2013;Schuenck et al, 2012). Moreover, in the present study, a VISA isolate belonging to USA1100/ST30 was identified, indicating the relevance of this lineage among the PVL-positive MRSA isolates.…”

“…Furthermore, analysis of a collection of bacterial isolates having a common characteristic, such as PVL genes, can help to understand the relationship between them. However, in general, available studies demonstrate only the occurrence of these isolates (Nichol et al, 2013;Cavalcante et al, 2015;Caboclo et al, 2013;Egea et al, 2014;Fernandez et al, 2012;Schuenck et al, 2012). In the present study, we analyzed a collection of 50 PVL-positive S. aureus isolates obtained in a 6-year period in Rio de Janeiro hospitals as their phenotypic and molecular characteristics.…”

“…aureus PVL-positive isolates have been related to severe disease (Tristan et al, 2007;Cavalcante et al, 2015) making its characterization very important. Furthermore, analysis of a collection of bacterial isolates having a common characteristic, such as PVL genes, can help to understand the relationship between them.…”

Systematic review about 10 interventions in dermatitis. A document from the Latin American Society of Allergy, Asthma, and Immunology

“…49,50 This bacterial overgrowth, with subsequent biofilm formation and mainly related to the pathogenic strains of Staphylococcus aureus (methicillin-resistant Staphylococcus aureus), would be directly related to changes in the cutaneous barrier. 51,52,53 Cutaneous microbiota is associated with dermatitis severity, but it is less clear its effect in the pathogenesis; antibiotic interventions are also expected to be able to improve the dermatitis symptom scores. However, a systematic review, 54 in 21 studies with different interventions (oral antibiotics, antibacterial soaps, topical steroids/antibiotics/antifungal, baths with antibacterial solutions) did not show differences statistically significant.…”

Staphylococcus aureus nasal isolates may have the same genetic profile in atopic dermatitis paediatric patients and their close contacts

“…Molecular characterization of S. aureus isolates may be achieved by, for example, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) [4,5]. Most of the S.aureus isolates recovered from AD children belong to well-established lineages of different geographical regions, such as USA1100/ST30, USA400/ST1 and USA800/ST5 in Brazil [6,7] and ST188 in Korea [8].…”