Purification and Characterization of Epidermin from Staphylococcus epidermidis and the Impact of Heavy Metals on its Antibacterial Properties

Epidermin, a bacteriocin produced by Staphylococcus epidermidis, possesses antimicrobial and anti-enzymatic characteristics. It has been speculated that heavy metals could enhance the inhibitory activities of epidermin against clinical pathogens. This study aimed to extract and characterize epidermin from Staphylococcus epidermidis and investigate the impact of heavy metals on its antibacterial action on Pseudomonas species. Staphylococcus epidermidis was collected and isolated from clinical and environmental samples in Baghdad, Iraq. The bacterial isolates were identified through phenotypic, microscopic, and VITEK 2 compact systems. Among the isolates, epidermin-producing strains were identified. Epidermin was extracted from the epidermin-producing isolates, purified, characterized, and fractionated. The effect of three heavy metal ions on the inhibitory activity of epidermin was tested against Pseudomonas species. One of the thirteen epidermin-producing isolates was selected for epidermin extraction. The epidermin crude concentration was determined to be 0.43 mg/ml, exhibiting 70% activity. The results also showed that 100 mM of cadmium increased epidermin activity, while 50 mM of cadmium showed less activity. Cobalt and copper demonstrated a similar inhibitory-enhancement activity. The present study found that the inhibitory activity of epidermin against Pseudomonas species could be enhanced with heavy metals. Further investigations are encouraged and recommended to explore the synergistic potential of epidermin and heavy metals as antimicrobial agents for controlling clinical pathogenic isolates.