Time-kill profiles and cell-surface morphological effects of crude Polycephalomyces nipponicus Cod-MK1201 mycelial extract against antibiotic-sensitive and -resistant Staphylococcus aureus

Abstract

Purpose: To examine the effect of crude Polycephalomyces nipponicus  Cod-MK1201 mycelial extract on the viability and cell surface morphology of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA).
Methods: Time-kill assays were conducted by incubating test bacteria with the extract and sampling at selected time points within a 24 h period. The effects of the extract on MSSA and MRSA ultrastructure were determined using a scanning electron microscope (SEM).
Results: Time-kill assay data indicate a bactericidal effect against both strains of staphylococci. The extracts were rapidly bactericidal at concentrations of 1 x MIC and 2 x MIC, achieving complete elimination of the test bacterial strains within 2 h. SEM micrographs of S. aureus taken after treatment with various concentrations of the extract revealed extensive morphological alterations to the cell surface of both MSSA and MRSA.
Conclusion: The results confirm the antibacterial activity of P. nipponicus Cod-MK1201 mycelial extract. Further research may allow this to be developed as an alternative therapy to alleviate S. aureus infection.

Keywords: Antibacterial activity, Polycephalomyces nipponicus, Staphylococcus aureus, Time-kill assay, Cell surface morphology