Subinhibitory Concentrations of Kojic Acid Reduce Enterotoxins A and α-hemolysin Production in Staphylococcus aureus Isolates

Abstract

Background: Staphylococcus aureus (S. aureus) is one of the most significant human pathogens that causes various sorts of diseases and invasive infections. Recently, due to the resistance of this bacterium to several medications, it has become difficult to treat infections caused by it. The use of biological compounds to control infections might be a solution to this challenge. This study aimed to investigate the influence of kojic acid (KA) on the expression of some virulence factors of S. aureus. Methods: Clinical samples were collected from hospital sources. The standard diagnostic test and molecular techniques were used to identify S. aureus strains. Minimal inhibitory concentrations (MICs) of KA were determined according to guidelines of the Clinical and Laboratory Standards Institute. The expression levels of α-hemolysin (hla) and enterotoxin A (sea) genes were measured in the presence and absence of KA using a real-time polymerase chain reaction technique. The obtained data were analyzed using standard statistical methods in SPSS software (version 16) and Prism GraphPad software. P < 0.05 was considered statistically significant in the comparative data. Results: The results indicated that the values of minimum inhibitory concentration (MIC) of S. aureus after KA treatment were 512 μg/mL. As a result, the expression of the hla gene was decreased 9 fold and the expression levels of the sea gene were decreased 2.7 fold. Conclusions: In this study, the desirable effects of KA on S. aureus strains were observed. In conclusion, the application of KA potentially reduces the virulence factors of S. aureus. These promising results can breathe hope in the fight against pathogenic S. aureus strains by repressing their virulence factors.

Keywords

• alpha hemolysin (hla)
• enterotoxin a (sea)
• gene expression
• kojic acid
• staphylococcus aureus