Development of Teicoplanin Tolerance by Staphylococcus epidermidis and Increased Susceptibility to Bacteriophage Type 92 by Methicillin-Resistant Staphylococcus aureus in Polymicrobial Biofilms

Abstract

Staphylococcus epidermidis is a commensal commonly found in polymicrobial biofilms with Staphylococcus aureus. Given the increasing drug resistance in Staphylococci, we explored combination therapy with teicoplanin and bacteriophage type 92 (Siphoviridae) on the survival and antibiotic tolerance of methicillin-resistant S. aureus (MRSA) and S. epidermidis to teicoplanin and bacteriophage in 48-h pure and mixed culture biofilms. The combination of teicoplanin and bacteriophage was more effective against MRSA, but not S. epidermidis monocultures, than the use of either teicoplanin or phage alone. In polymicrobial biofilms, however, MRSA acquired increased susceptibility to phage infection and S. epidermidis acquired increased tolerance to teicoplanin, as well as increased fitness. The results demonstrate bacteriophage alone was more effective against MRSA and S. epidermidis in polymicrobial biofilms compared to the combination of bacteriophage and teicoplanin.