Severity of Atopic Dermatitis and Coagulase Types of Staphylococcus aureus and Others.

Staphylococcus species populating the cheeks of 16 infant atopic dermatitis (AD) patients and of 14 healthy infants (HI) were selectively collected with film stamp check mannitolsalt agar. While most (88%) of the 16 infant AD patients carried Staphylococcus aureusas skin flora, only 2 out of 14 HI (14%) had that organism. As the skin rash grade ofinfant AD patients became more severe, the average numbers of S. aureus were higher. Thenumber of S. aureus isolated from the case of mild, moderate and severe skin rash (average± standard derivation) were 2.07±0.22, 2.43±0.11 and 2.84±0.11 log colony forming unit (CFU)/10cm2, respectively, while the average number of S. aureus isolated from HI was1.65 log CFU/10cm2. The average number of 13 S. epidermidis strains (2.36±0.12log CFU/10cm2) and of 8 other coagulase negative staphylococci (CNS) strains (1.77±0.14log CFU/10cm2) were also higher than that of 2 S. aureus strains found in HI. In contrast, in infant AD patients, the average number of 14 S. aureus strains (2.50±0.21log CFU/10cm2) was higher than that of 12 CNS strains (2.07±0.09 log CFU/10cm2). Theseresults suggest that pathogenic species are more common and present in greater numbers ininfant AD patients compared to those in HI. Almost of species isolated from HI were consideredto be non-pathogenic. Coagulase type II, type III, type IV, type V, typeVII and typeVIII of S. aureus were seen in 2, 4, 2, 1, 2 and 1 infant AD patients, respectively, whilecoagulase type I and type VI were not seen. Case numbers in present study were small, butthere was no distinct correlation between skin rash grade of infant AD patients and thecoagulase type of S. aureus. But differences of antimicrobial sensitivity between coagulasetype of S. aureus should not be ignored. In addition, the major coagulase type suggested thatS. aureus infection origin in infant AD patients might not be the chief causative organismsof other infectious skin diseases such as impetigo or furuncle.