Cosmetic preservative exposure promotes persistent and antibiotic resistance of staphylococci by chromosome mutations

OBJECTIVES: Antibiotic-resistant staphylococci are common skin colonisers and an important public-health concern. The role of cosmetic preservatives in selecting resistance is unclear. We examined whether exposure to widely used preservatives promotes antibiotic resistance in Staphylococcus spp. and explored underlying mechanisms. METHODS: Methicillin-resistant and susceptible S. aureus (MRSA and MSSA) and S. epidermidis (MRSE and MSSE) were exposed to dimethylol dimethyl hydantoin (DMDMH, 15-100 µg/ml), Diazolidinyl Urea (IU, 10-300 µg/ml), Sodium methyl p-hydroxybenzoate (MP, 50-3000 µg/ml), respectively, and nutrient agar plates supplemented with 1 ×MIC of chloramphenicol, kanamycin, oxacillin or tetracycline were used to isolate mutants. Minimum inhibitory concentrations and time-killing curves of mutants were determined. Genome sequencing was applied to MSSA and MRSE, and transcriptome sequencing was applied to MSSA to clarify the mutation sites and their role in promoting antibiotic resistance of MSSA. RESULTS: mutation. CONCLUSIONS: mutations.