Nanocurcumin: An Innovative Strategy to Combat Virulence and Methicillin Resistance in Staphylococcus aureus Isolated...

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen that causes various infections and exhibits antibiotic resistance and virulence factors, requiring alternative therapies. This study aimed to evaluate the effects of nanocurcumin on gene expression of S. aureus isolates from burn wounds in Iraqi patients, focusing on inhibiting resistance and virulence genes.

From March 2023 to May 2024, burn wound samples from Iraqi patients yielded 110 S. aureus isolates. Identification was conducted by Gram staining, biochemical assays, and culture techniques. Fifty isolates were randomly selected for antibiotic susceptibility testing using the VITEK 2 Compact System. Ten isolates showing the highest resistance to multiple antibiotics were selected for molecular characterization via Multiplex polymerase chain reaction (Multiplex PCR) to detect fnbA, icaA, icaB, ftsZ, hla, pvl, femA, and mecA genes. The ten isolates were then divided into two groups a treatment group exposed to nanocurcumin and an untreated control group. The MIC (minimum inhibitory concentration) of nanocurcumin was determined using the broth microdilution method in a 96-well plate. The 16S rRNA gene served as an internal control for evaluating the molecular effects. A two-tailed t test was used to assess the significance of gene expression differences.

All 110 isolates were confirmed as S. aureus. The 50 selected isolates were resistant to cefoxitin, amoxicillin, benzylpenicillin, ampicillin/sulbactam, piperacillin/tazobactam, cloxacillin, oxacillin, and azithromycin. MecA gene was detected in all isolates. Among the ten tested, femA, icaA, hla, and ftsZ were present in 70%; pvl in 50%; icaB in 20%; and fnbA in 10%. Quantitative reverse transcription polymerase chain reaction (qRT-PCR), showed significant downregulation of icaA, hla, pvl, femA, and mecA in treated isolates. No significant changes were seen in fnbA and ftsZ.

Nanocurcumin inhibits S. aureus virulence and resistance genes, reducing biofilm formation and toxin production, but lacks effect on fnbA and ftsZ, requiring further research.