Effects of various types of Triton X on the susceptibilities of methicillin-resistant staphylococci to oxacillin

We examined the effect of six types of the nonionic detergent Triton X on the susceptibilities of methicillin-resistant staphylococci to oxacillin. We used five methicillin-resistant Staphylococcus aureus isolates and 17 methicillin-resistant coagulase-negative staphylococci isolates. All strains of S. aureus, S. epidermidis and S. sciuri had enhanced susceptibility to oxacillin following exposure to the types of Triton X having 7–13 polymerized ethylene oxides. These strains were altered from homogeneously resistant to heterogeneously resistant by Triton X-100. Those types of Triton X that affected the resistance level also promoted the release of lipoteichoic acid. These results and those of previous studies suggest that Triton X might act on factors other than the mecA or femA products.