A composition is provided, which comprises a mixture of a polymeric biguanide polymer and an alkyl and/or dialkyl oxyethylene methyl ammonium salt, or pharmaceutical acceptable salts or tautomers thereof, for use in the treatment, prevention and/or amelioration of an infection with a microorganism with antimicrobial resistance, such as methicillin resistant Staphylococcus aureus (MRSA).
