Perfil de diversidade da comunidade estafilocócica da pele em doentes com dermatite atópica

Introduction: Atopic dermatitis (AD) is a chronically inflammatory immunological mediated skin disease where the majority of patients are colonized with Staphylococcus aureus (S. aureus) capable of producing a quantity of virulence factors. S. aureus can be cultured from 90% of skin lesions and can colonize normal -appearing skin in patients with AD. Coagulase negative staphylococci (CNS) generally do not produce such toxins with superantigenic activity, but their role in AD pathogenicity should not be ruled out. Our aim was to study the staphylococcal community from skin of AD patients and normal healthy individuals without skin disruption, as well as some of the virulence factors present in these isolates. Methods: All staphylococcal isolates were subject to numerical analysis of some essential virulence factors. The majority of the staphylococcal species were coagulase (158/238 isolates) and deoxyribonuclease (161/238 isolates) negative. The wild strains isolated from the skin surface of healthy and AD individuals were submitted to multiplex PCR to identify the bacteria belonging to the S. aureus, S. epidermidis, S. capitis, S. hominis and S. haemolyticus species by yielding specific DNA fragments of 700, 124, 208, 806 and 271 bp, respectively. Complementary identification of each isolate previously identified by multiplex PCR and remaining 22 unidentified isolates was performed by sodA gene sequencing. Results: The staphylococcal microflora of the skin was dominated by S. aureus (71/196 isolates) followed by S. epidermidis (59/196 isolates) species in AD patients. In healthy individuals a high prevalence of S. warneri (9/42 isolates) followed by S. aureus (5/42 isolates) and S. haemolyticus (5/42 isolates) species was detected. High biodiversity in the skin of healthy individuals with eight staphylococcal species identified; whereas in the skin of AD patients only four species were distinguished Conclusion: Our study highlighted the higher diversity of the staphylococcal community occurring in the skin of healthy individuals versus AD patients. The predominance of S. aureus on the skin of individuals with AD suggests high properties of adaptation of this species to the disease condition. Future perspectives include the detailed characterization of the staphylococcal community and virulence profile for each patient as a mean of tailor made therapeutic approach; the symbiotic versus antagonistic relation between commensals and pathogenic species of Staphylococcus should be further investigated.