Abstract: Background: Topical antimicrobial drugs are indicated for limited superficial pyodermitis treatment, although they are largely used as self-prescribed medication for a variety of inflammatory dermatoses, including atopic dermatitis. Monitoring bacterial susceptibility to these drugs is difficult, given the paucity of laboratory standardization. Objective: To evaluate the prevalence of Staphylococcus aureus topical antimicrobial drug resistance in atopic dermatitis patients. Methods: We conducted a cross-sectional study of children and adults diagnosed with atopic dermatitis and S. aureus colonization. We used miscellaneous literature reported breakpoints to define S. aureus resistance to mupirocin, fusidic acid, gentamicin, neomycin and bacitracin. Results: A total of 91 patients were included and 100 S. aureus isolates were analyzed. All strains were methicillin-susceptible S. aureus. We found a low prevalence of mupirocin and fusidic acid resistance (1.1% and 5.9%, respectively), but high levels of neomycin and bacitracin resistance (42.6% and 100%, respectively). Fusidic acid resistance was associated with more severe atopic dermatitis, demonstrated by higher EASI scores (median 17.8 vs 5.7, p=.009). Our results also corroborate the literature on the absence of cross-resistance between the aminoglycosides neomycin and gentamicin. Conclusions: Our data, in a southern Brazilian sample of AD patients, revealed a low prevalence of mupirocin and fusidic acid resistance of S. aureus atopic eczema colonizer strains. However, for neomycin and bacitracin, which are commonly used topical antimicrobial drugs in Brazil, high levels of resistance were identified. Further restrictions on the use of these antimicrobials seem necessary to keep resistance as low as possible.

FUNDAMENTOS:A Dermatite Atópica cursa com alteração da barreira cutânea e colonização bacteriana; a relação deste último fator com a gravidade da doença e a frequência das exacerbações não é completamente conhecida.OBJETIVOS:Verificar a gravidade da Dermatite Atópica e o número de consultas ocasionadas pela dermatose, comparando pacientes colonizados e não colonizados pelo Staphylococcus aureus (S. aureus). Verificar a frequência de colonização por Staphylococcus aureus meticilina resistentes da comunidade.MÉTODOS:Estudo de coorte, com 12 meses de acompanhamento, em amostra de pacientes da rede pública de Porto Alegre, RS. Realizaram-se culturais de lesões ativas e fossas nasais e testes de sensibilidade à meticilina para o S. aureus. A gravidade da Dermatite Atópica foi estabelecida pelo Eczema Area and Severity Index.RESULTADOS:Incluídos 93 pacientes, 43% femininos e 56% masculinos, 26 colonizados por S. aureusna região nasal, 56 em lesão cutânea. A média do Eczema Area and Severity inicial foi 5,5 e a do final 3,9. O Eczema Area and Severity Index inicial dos pacientes colonizados por S. aureusem lesão cutânea e nas fossas nasais foi maior que o dos pacientes não colonizados (p< 0,05). Em um ano, seis consultas por paciente ocorreram, em média. Houve correlação linear entre o número de consultas em um ano e o Eczema Area and Severity Index inicial (r = 0,78). Não houve encontro de Staphylococcus aureus meticilina resistentes da comunidade.CONCLUSÃO:Há uma importante influência da colonização estafilocócica na gravidade da Dermatite Atópica e no número de consultas por sua exacerbação. A resistência à meticilina entre os S. aureusnão parece constituir-se como problema emergente, nesta amostra brasileira.

BACKGROUND:Atopic dermatitis leads to epidermal barrier dysfunction and bacteria colonization. The relationship of the last factor with the severity of the disease and the frequency of exacerbation is not fully known.OBJECTIVES:Verify the severity of the atopic dermatitis and the number of appointments generated by dermatosis, comparing patients colonized with patients not colonized by S. aureus. Verify the frequency of colonization by methicillin resistant Staphylococcus aureus acquired in the community.METHODS:Cohort study with a 12 months follow-up, in a sample of patients from Porto Alegre, RS public network. Cultures in active injuries and nasal cavities were carried out as well as methicillin sensitivity tests to S. aureus.The severity of atopic dermatitis was defined by Eczema Area and Severity Index (EASI).RESULTS:We included 93 patients, 43% female and 56% male, 26 colonized by S. aureusin the nasal orifices, 56 in the skin damage. The mean of initial Eczema Area and Severity Index was 5.5 and final 3.9. The initial Eczema Area and Severity Index of patients colonized by S. aureusin the skin and nasal cavity was larger than the number of patients without colonization(p< 0.05). During the period of one year, in average, there were six appointments/patient. There was linear correlation between the number of appointments during one year and the inicial Eczema Area and Severity Index (r = 0,78). There were no patients with methicillin resistant Staphylococcus aureus acquired in the community.CONCLUSION:There is a relevant influence of staphylococcal colonization on the severity of atopic dermatitis and the number of appointments required by its exacerbation. Methicillin resistance among those affected by S. aureusdoes not seem to be an emergent problem, in this Brazilian sample.