title: Exploring Staphylococcus epidermidis in atopic eczema: friend or foe?
abstract: BACKGROUND
  Staphylococcus aureus (SA) colonization/infection is important in the pathophysiology of childhood atopic dermatitis (AD), but the role of Staphylococcus epidermidis (SE) is unknown.
  
  
  OBJECTIVE
  To evaluate if SE co-infects with SA and is associated with more severe disease.
  
  
  METHODS
  Associations between bacteriological culture results of skin swabs (taken from the most severely affected area and at the antecubital fossa) and SCORing Atopic Dermatitis (SCORAD) score, skin hydration, transepidermal water loss (TEWL) and quality of life (QoL) were evaluated.
  
  
  RESULTS
  In 100 consecutive patients with AD (aged 12.4 ± 4.8 years), SE was present in 28% and 32% of the swabs taken from the most severe area and the flexural area (antecubital fossa), respectively, whereas SA was present in 69% and 55%, respectively. Binomial logistic regression showed that SE was inversely associated with SA growth in the most severely affected skin site [adjusted odds ratio (aOR) = 0.42, 95% CI 0.22-0.81; P = 0.01], frequency of emollient usage (aOR = 0.50, 95% CI 0.29-0.87; P = 0.01) and frequency of oral antihistamine usage (aOR = 0.81, 95% CI 0.65-0.10, P < 0.05), but positively associated with objective SCORAD (aOR = 1.04, 95% CI 1.00-1.02; P < 0.05). SE in the antecubital fossa was not associated with SA growth, disease severity, QoL or any clinical parameters.
  
  
  CONCLUSIONS
  SE may not be just a commensal bystander in the skin microbiota. The organism amensalistically displaces SA and is associated with more severe disease.
authors.affiliation: Department of Paediatrics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
authors.forename: K L
authors.initials: KL
authors.lastname: Hon
authors.affiliation: Department of Paediatrics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
authors.forename: Y C K
authors.initials: YC
authors.lastname: Tsang
authors.affiliation: Department of Paediatrics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
authors.forename: N H
authors.initials: NH
authors.lastname: Pong
authors.affiliation: Department of Paediatrics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
authors.forename: T F
authors.initials: TF
authors.lastname: Leung
authors.affiliation: Department of Microbiology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
authors.forename: M
authors.initials: M
authors.lastname: Ip
mesh_terms: D000293:Adolescent; D002648:Child; D003876:Dermatitis, Atopic / Q000382:microbiology* / Q000473:pathology; D004485:Eczema / Q000382:microbiology* / Q000473:pathology; D004643:Emollients / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D011788:Quality of Life; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012867:Skin / Q000382:microbiology / Q000473:pathology; D013203:Staphylococcal Infections / Q000503:physiopathology; D013211:Staphylococcus aureus / Q000254:growth & development / Q000302:isolation & purification / Q000472:pathogenicity; D013212:Staphylococcus epidermidis / Q000302:isolation & purification* / Q000472:pathogenicity
chemical_list: D004643:Emollients