Skin bacterial colonizations and superinfections in immunocompetent patients with scabies

Background: Skin bacterial colonizations and superinfections are well-known complications of scabies, in particular, in tropical and subtropical countries. However, only very rare studies on skin bacterial colonizations and superinfections have been carried out in immunocompetent patients with scabies living in Western countries. Methods: Eighty-nine Caucasian adult immunocompetent patients with scabies living in Milan, Italy, were subjected to bacteriologic examinations of the skin. Clinical diagnosis of scabies was confirmed in all patients by means of microscopic examinations: they were considered positive when adults or eggs or feces of Sarcoptes scabiei var. hominis were visible. In all patients, six skin swabs (three for aerobic and three for anaerobic bacteria) were taken in three different areas before the beginning of the treatment. Results: No clinical manifestations of pyoderma were observed. Bacteriologic examinations were positive in 5/89 patients (5.6%). Bacteriologic cultures were positive for Staphylococcus aureus in all five patients; in one patient, they were also positive for Escherichia coli. No growth of anaerobic bacteria was recorded. Conclusions: According to the results of this study, skin bacterial colonizations and superinfections in immunocompetent adult patients with scabies living in Milan are uncommon. Bacteriologic examinations may therefore be considered as an unnecessary routine procedure.