Antimicrobial susceptibility of Staphylococcus aureus in children with atopic dermatitis


Wen-Tsung Lo, MD PhD, Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, No. 325, Cheng-Kung Road, Section 2, Nei-hu 114, Taipei, Taiwan. Email:


Background:  Skin infection and/or nasal carriage of Staphylococcus aureus in children with atopic dermatitis (AD) is a risk factor for exacerbating disease or subsequent recurrent S. aureus infection. The purpose of the study is to evaluate the antibiotic susceptibilities of S. aureus strains from AD children and determine the most appropriate choice of antibiotics.

Methods:  Nasal swabs from 168 healthy children with AD and 20 AD children with concurrent skin and soft-tissue infections (SSTI) were collected in 2005–2008. S. aureus strains were further analyzed for and compared with antibiotic susceptibilities.

Results:  There were 78 (46.4%) healthy children with AD colonized with S. aureus, and 24 (30.8%) were methicillin-resistant S. aureus (MRSA). Among the 20 SSTI-infecting strains, 12 (60%) were MRSA. Antimicrobial susceptibility testing showed that, after penicillin, colonizing and SSTI-infecting strains had the highest rates of resistance to erythromycin (50% and 70%, respectively). All isolated strains were susceptible to vancomycin, rifampin, and mupirocin. Multi-drug resistance was found in 70% of the colonizing and 50% of the SSTI-infecting strains. D-test assay revealed inducible clindamycin resistance in 75% of the colonizing strains. The most prevalent resistance gene was ermB which was present in 94.9% and 92.9% of colonizing and SSTI-infecting strains, respectively.

Conclusions:  This study found that colonizing and SSTI-infecting strains of S. aureus from AD children had a high prevalence of MRSA and multi-drug resistance. Trimethoprim-sulfamethoxazole, rifampin, fusidic acid and mupirocin appear to be more suitable for treatment and decolonization of S. aureus in AD children.