RESUMO

BACKGROUND: Progressive macular hypomelanosis (PMH) is a dermatosis of unknown etiology. It has been concluded that it involves the presence of Propionibacterium acnes, a saprophyte of the pilosebaceous follicles. In our study, we investigated the presence of P. acnes in lesional and non-lesional skin of patients with PMH through quantitative real-time polymerase chain reaction (PCR) and bacterial culture from a skin fragment. MATERIALS AND METHODS: An observational, exploratory study, with laboratory comparison of lesional (study group) and non-lesional skin (comparison group), in patients with PMH, was carried out with 36 patients, seen in the dermatology outpatient setting at the Oswaldo Cruz University Hospital (OCUH), Recife, Pernambuco, Brazil, between March and May 2008. All patients were submitted to a Wood's lamp examination, mycological research, and biopsies of lesional and non-lesional skin from the back. Skin fragments were submitted to a histopathology test, bacterial culture, and a quantitative real-time PCR test. The program Statistical Package for Social Sciences, version 12.0, was employed for relationship analysis with the Wilcoxon and McNemar tests. RESULTS: There was a significant predominance of P. acnes on lesional skin, in comparison to non-lesional skin (P<0.001), as demonstrated by culture and quantitative real-time PCR. CONCLUSION: Although P. acnes is a saprophyte, the hypothesis may be raised that this microorganism participates in the development of PMH.

Assuntos

Infecções por Bactérias Gram-Positivas/microbiologia , Hipopigmentação/microbiologia , Propionibacterium acnes/isolamento & purificação , Adolescente , Adulto , Feminino , Infecções por Bactérias Gram-Positivas/complicações , Infecções por Bactérias Gram-Positivas/patologia , Humanos , Hipopigmentação/patologia , Masculino , Reação em Cadeia da Polimerase em Tempo Real , Adulto Jovem

RESUMO

Little is known about the etiology of progressive macular hypomelanosis, although it has been suggested that Propionibacterium acnes plays an important role. While microbiological culture is commonly employed to identify Propionibacterium acnes, new identification methods have been under investigation, amongst them polymerase chain reaction. To determine the cut-off point for the number of genome copies of Propionibacterium acnes in the lesional skin of patients with progressive macular hypomelanosis as a positive marker, employing quantitative real-time polymerase chain reaction and anaerobic culture, considered gold standard. An observational study with a comparison group, included 35 patients with dermatosis, attended at the Oswaldo Cruz University Hospital, Pernambuco, Brazil, between March and May 2008. Lesional skin was compared to non-lesional skin through positive testing with real-time polymerase chain reaction and culture. The Statistical Package for Social Sciences, version 12.0, was employed for the association analysis with the McNemar test, and the cut-off point with the ROC curve for maximum values. Propionibacterium acnes was most frequently encountered in lesional areas (p<0,025). The cut-off point of Propionibacterium acnes in lesional skin was 1,333 genome copies, with a sensitivity of 87,9% and a specificity of 100,0%. Since Propionibacterium acnes is a saprophyte, identifying the cut-off point may assist in determining its positivity in lesional skin in patients suffering with this dermatosis.