Increasing the sensitivity of Staphylococcus aureus izolates to β-lactam group antibiotics with astaxanthin

Staphylococcus aureus (S. aureus), a Gram-positive bacteria, typically colonizes the skin surface and nasopharynx. S. aureus which transmits through direct contact does not infect healthy skin, but when it enters tissues or the bloodstream, it can cause very serious infections. Due to its ability to produce biofilms, it is difficult to treat, resulting in high mortality and morbidity. In 1928, penicillin was discovered by A. Fleming and started to be used in staphylococcal infections, but after a short time, resistance began to develop as staphylococci produced penicillinase. With the use of methicillin after penicillin, S. aureus strains that are also resistant to methicillin (MRSA) emerged in a short period of time and this situation has become a serious health problem. New antimicrobial agents and combinations are needed due to the increasing difficulty of antibiotic treatment, especially in multi-drug resistant and biofilm producing strains such as MRSA. In this study, antibacterial and antibiofilm effects of various dose combinations of β-Lactam group antibiotics and Astaxanthin on biofilm producing S. aureus isolates were determined. Since biofilm-producing S. aureus isolates develop resistance to most antibiotics and inhibiting biofilm structures requires high doses of antibiotics, it was aimed to increase the antimicrobial and antibiofilm susceptibility of biofilm-producing S. aureus isolates by combining various doses of β-Lactam group antibiotics with astaxanthin. In this study, the presence of mecA and nuc genes in biofilm-forming MRSA and MSSA isolates were determined, the doses at which Astaxanthin was effective on the isolates and the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of β-lactam antibiotics were determined and the Checkerboard method was adapted and used to observe the effects of the combinations on planktonic bacteria. MtP method was used to measure the antibiofilm effect of combinations of astaxanthin and β-lactam antibiotics. It was observed that the combination of the agents affected the biofilm formation. When the results of our study were examined, it was observed that Astaxanthin, at certain doses, increased antibiotic susceptibility and sensitized antibiotic resistance, decreased the MIC doses of antibiotics up to 32-fold in MSSAs in biofilm production, and decreased the MIC doses between 2 and 32-fold in MRSAs. Based on this result, the combination of astaxanthin and β-lactam antibiotics can be considered as a treatment option especially for MRSA-induced biofilm infections. Keywords : Biofilm, MRSA, MSSA, Antibiotic Resistance, Astaxanthin