Recombinant Oncorhyncin II Effect on the Treatment of Methicillin-Resistant Staphylococcus aureus Skin Infection

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is known to be one of the most potentially pathogenic organisms in the world. Skin infections are one of the significant infections of S. aureus. Therefore, therapeutic constraints have challenged researchers to seek new strategies to produce new medicines. Antimicrobial peptides (AMPs) are a new generation of natural drugs with antimicrobial properties and high fatality potency. Oncorhyncin II AMP is a group of peptides with bacteriostatic activity and antimicrobial effect against Gram-positive and Gram-negative bacteria. Therefore, the development and promotion of antimicrobial peptides can be a new step in the treatment of skin infections due to bacterial resistant S. aureus in hospitals. Objectives: The objective of this study was to produce recombinant Oncorhyncin II protein and evaluate its antimicrobial effects on MRSA to determine the outcomes of the treatment. Methods: In this experimental study, the Oncorhyncin II Antimicrobial peptide was synthesized by the recombinant method. The effectiveness of this peptide was assessed by the minimum inhibitory concentration (MIC) test. The activity of recombinant protein against S. aureus was investigated using in vitro and in vivo experiments. Results: The effectiveness of this peptide obtained by the MIC test was 225 µg/mL. The activity test confirmed the MIC test and showed that this antimicrobial peptide has been able to reduce MRSA cell growth. All mice infected with MRSA responded positively to the protein treatment. Conclusions: According to Oncorhyncin II antimicrobial peptide activity studies, this peptide, as a new generation of antibiotics, was expected to have positive outcomes in the improvement of S. aureus skin infections. Therefore, the results of the efficacy require further studies to be confirmed.

In Vitro Pharmacokinetics of LL-37 and Oncorhyncin II Combination Against Acinetobacter baumannii

“…Following purification processes, the recombinant proteins were readily recovered by nickel affinity chromatography with a purity of more than 70% (32). It has been confirmed in previous studies that the amino acids arginine and proline might increase the performance of proteins that have been reassembled utilizing a dialysis technique (15,18). It is considered very valuable that the final produced recombinant LL-37 and oncorhyncin II in this study were effective against Gramnegative bacteria, including A. baumannii.…”

“…The AMP LL-37 (LLGDF-FRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) and oncorhyncin II (KAVAAKKSPKKAKKPATPKKAAKSPKKVKKPAAAAKKAAK-SPKKATKAAKPKAAKKAAKAKKAAPKI) were acquired from Cambridge Biomatik Company (Cambridge, Canada). Then, the plasmid pET32a (Novagen, India) was prepared as expression vector (15,16). Subsequently, Escherichia coli BL21 (DE3), the common expression host, were applied to proceed recombinant protein expression.…”

“…The cells were extracted after a 4-hour incubation period by centrifugation at 5000 rpm for 20 minutes. Transferring the resultant protein to the (12%) sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) proved the induction results (15,18). Purification was determined using Ni-NTA agarose resin affinity chromatography (Qiagen, Alameda, CA, USA) under denaturing conditions with 8 M urea (18).…”

“…The PBS buffer was changed every 2 hours to improve dialysis efficiency. Finally, the dialyzed protein was kept at 4°C for future testing (15,20). Due to refolded recombinant proteins' low concentrations in the dialyzer tubes, a 10 kDa pore-size Amicon centrifugal filter (Merck Millipore, Darmstadt, Germany) was applied to increase their concentrations (21).…”

“…The turbidity of these samples was determined with a spectrophotometer (at 600 nm) along the intervals of 0, 1, 3, 5, 7, 11, and 20 hours. The assay was carried out in triplicate (15).…”