Effects of Piper cubeba L. essential oil on methicillin‐resistant Staphylococcus aureus: an AFM and TEM study

Abstract

The increasing prevalence of antibiotic-resistant bacteria is creating a real challenge for health care systems worldwide, making the development of novel antibiotics a necessity. In addition to the development of new antibiotics, there is an urgent need for in-depth characterization of the mechanisms of bacterial resistance toward new drugs. Here, we used essential oils extracted in our laboratory from Piper cubeba against methicillin-resistant Staphylococcus aureus ATCC 43300, one of the most prominent antibiotic-resistant bacteria. Effects of the essential oils extracted from P cubeba on bacteria were mainly evaluated using 2 powerful microscopy techniques: atomic force microscopy and transmission electron microscopy. High-resolution atomic force microscopy images of the cells were obtained close to their native environment by immobilizing the cells on porous Polyether sulfone membranes, which were prepared in our laboratory with a wide range and distribution of pore sizes and depth. Inhibition zones (mm) and minimum inhibitory concentrations were determined. Two different concentrations of the oil were used to treat the cells: 50 μg/mL minimum inhibitory concentration and 25 μg/mL. The 50 μg/mL oil solution caused severe damage to the bacterial cells at microscopic levels while the 25 μg/mL solution showed no effects compared to the control. However, at nanoscopic levels, the 25 μg/mL oil solution caused significant changes in the cell wall, which could potentially impair bacterial activities. These results were also confirmed by transmission electron microscopy micrographs. Our results indicate that the extract has a good biological activity against methicillin- and oxacillin-resistant S aureus and that it acts on the cell wall and plasma (cytoplasmic) membrane.

Antimicrobial activity and synergism of ursolic acid 3-O-α-L-arabinopyranoside with oxacillin against methicillin-resistant Staphylococcus aureus

“…Understanding the fine ultrastructure of the bacterial cell wall is important to gain insight into bacterial physiology and the mechanism of action of antibiotics against bacteria (40). Using TEM to observe morphological changes in bacterial cells provides useful insights into the mechanism underlying the activity of antibacterial agents (41).…”

The impact of Cymbopogon martinii essential oil on Cutibacterium (formerly Propionibacterium) acnes strains and its interaction with keratinocytes

“…In a recent study with Piper cubeba L. EO, transmission electron microscopy confirmed that this EO caused significant changes in the cell wall; Alharbi et al . suggested that it could potentially impair bacterial activity in S. aureus .…”

“…In a recent study with Piper cubeba L. EO, transmission electron microscopy confirmed that this EO caused significant changes in the cell wall; Alharbi et al [21] suggested that it could potentially impair bacterial activity in S. aureus. Cinnamaldehyde in a concentration of 100 lg/ml and geraniol 200 lg/ml against Escherichia coli and the same compounds at 400 and 1450 lg/ml, respectively, against resistant Staphylococcus aureus showed interactions with cell wall similar with our data in C. acnes.…”

Incidence of Malignancy in the Future?

“…Now, we can see beta-lactamase-producing Letters to Editor bacteria, methicillin-resistant bacteria, and extended methicillin-resistant Staphylococcus aureus. [2] Above said was an example for genetic modification for sustaining life. Similar effect might happen in human genome also, that make our genome resistant against environmental toxins.…”