Expression of icaA, B, D, R and ebps biofilm-associated genes in methicillin-resistant-Staphylococcus aureus in exposure to curcumin

Abstract

BackgroundBiofilm formation is a paramount event to develop withstanding and sustainable biofilms by bacterial species. Methicillin-resistant Staphylococcus aureus (S. aureus, MRSA) causes a variety of infections. Our aim was evaluation of effect of curcumin compound on the expression of icaA, B, D, R and ebps genes related to biofilm formation among MRSA from blood samples. MethodsOne-hundred MRSA were collected from blood samples. Various concentrations of curcumin were assessed for antimicrobial effect including 1, 2, 5, 10 and 20 mg/mL in 96-well plates and incubated for 24 h. Curcumin at concentration of 2 mg/mL was prepared and exposed to bacterial culture (with a suspension equal to 0.5 Mac Farland) and incubated for 24 h. The expression of icaA, B, R and ebps genes related to biofilm formation was measured in exposure to 2 mg/mL of curcumin using real-time PCR method. ResultsPrevious hospitalization (58%, p = 0.0372) and antibiotic consumption (76%, p = 0.0023) were found as major risk factors of MRSA isolation. The minimum inhibitory and bactericidal concentrations (MIC and MBC, respectively) of curcumin ranged 5–10 and 10- > 20 mg/mL, respectively. The curcumin exerted a significantly higher anti-biofilm effect at concentrations 5, 10 and 20 mg/mL compared to the control group. The expression of icaA, B, D and ebps genes decreased 1.8 fold (p = 0.011), 2 fold (p = 0.002), 2.3 fold (p < 0.001) and 3 fold (p < 0.001), respectively which was significant, but the expression of the icaR was not significantly decreased (0.3 fold, p = 0.339). ConclusionThe curcumin compound had antimicrobial effect against MRSA. The expression of biofilm-associated genes was decreased in exposure to sub-MIC concentration of curcumin. Therefore, curcumin has the potential of application as an alternative antimicrobial agent.