Staphylococcus aureus resistance to topical antimicrobials in atopic dermatitis

Abstract

BackgroundTopical antimicrobial drugs are indicated for limited superficial pyodermitis treatment, although they are largely used as self-prescribed medication for a variety of inflammatory dermatoses, including atopic dermatitis. Monitoring bacterial susceptibility to these drugs is difficult, given the paucity of laboratory standardization.ObjectiveTo evaluate the prevalence of Staphylococcus aureus topical antimicrobial drug resistance in atopic dermatitis patients.MethodsWe conducted a cross-sectional study of children and adults diagnosed with atopic dermatitis and S. aureus colonization. We used miscellaneous literature reported breakpoints to define S. aureus resistance to mupirocin, fusidic acid, gentamicin, neomycin and bacitracin.ResultsA total of 91 patients were included and 100 S. aureus isolates were analyzed. All strains were methicillin-susceptible S. aureus. We found a low prevalence of mupirocin and fusidic acid resistance (1.1% and 5.9%, respectively), but high levels of neomycin and bacitracin resistance (42.6% and 100%, respectively). Fusidic acid resistance was associated with more severe atopic dermatitis, demonstrated by higher EASI scores (median 17.8 vs 5.7, p=.009). Our results also corroborate the literature on the absence of cross-resistance between the aminoglycosides neomycin and gentamicin.ConclusionsOur data, in a southern Brazilian sample of AD patients, revealed a low prevalence of mupirocin and fusidic acid resistance of S. aureus atopic eczema colonizer strains. However, for neomycin and bacitracin, which are commonly used topical antimicrobial drugs in Brazil, high levels of resistance were identified. Further restrictions on the use of these antimicrobials seem necessary to keep resistance as low as possible.

Topical (local) antibiotics for respiratory infections with sore throat: An antibiotic stewardship perspective

“…Although the causality is not clear, bacitracin resistance has been reported in Streptococcus pyogenes isolated from patients with pharyngitis . Additionally, bacitracin‐resistant strains of S pyogenes have been recovered from patients with both invasive and non‐invasive infections, and bacitracin‐resistant strains of Staphylococcus aureus have been described in patients with atopic dermatitis . Neomycin‐resistant strains of Escherichia coli have been isolated from patients with urinary tract and gastrointestinal infections, and resistant Pseudomonas aeruginosa has been recovered from ear and skin infections .…”

Topical antibiotics in the dermatological clinical practice: Indications, efficacy, and adverse effects

“…However, also in atopic dermatitis, it is extremely important to use topical antibiotics only in the presence of clear evidence of secondary infections, in order to avoid bacterial resistances. In 2016, Bessa et al published an interesting study assessing S aureus resistance to topical antimicrobials in atopic dermatitis patients and demonstrating high bacterial resistance levels against bacitracin, neomycin, fusidic acid, and mupirocin 35 …”

The Role of Immune Defects and Colonization ofStaphylococcus aureusin the Pathogenesis of Atopic Dermatitis

“…Unfortunately, more and more often, S. aureus becomes resistant to the most commonly used preparations. In the study conducted by Bessa et al, the frequency of fusidic acid and mupirocin resistant strains was low; however, the high rate of neomycin and bacitracin resistance is alarming as those antibiotics are common in clinical practice [ 56 ].…”