Identification and Characterization of RK22, a Novel Antimicrobial Peptide from Hirudinaria manillensis against Methicillin Resistant Staphylococcus aureus

Staphylococcus aureus (S. aureus) infections are a leading cause of morbidity and mortality, which are compounded by drug resistance. By manipulating the coagulation system, S. aureus gains a significant advantage over host defense mechanisms, with hypercoagulation induced by S. aureus potentially aggravating infectious diseases. Recently, we and other researchers identified that a higher level of LL-37, one endogenous antimicrobial peptide with a significant killing effect on S. aureus infection, resulted in thrombosis formation through the induction of platelet activation and potentiation of the coagulation factor enzymatic activity. In the current study, we identified a novel antimicrobial peptide (RK22) from the salivary gland transcriptome of Hirudinaria manillensis (H. manillensis) through bioinformatic analysis, and then synthesized it, which exhibited good antimicrobial activity against S. aureus, including a clinically resistant strain with a minimal inhibitory concentration (MIC) of 6.25 μg/mL. The RK22 peptide rapidly killed S. aureus by inhibiting biofilm formation and promoting biofilm eradication, with good plasma stability, negligible cytotoxicity, minimal hemolytic activity, and no significant promotion of the coagulation system. Notably, administration of RK22 significantly inhibited S. aureus infection and the clinically resistant strain in vivo. Thus, these findings highlight the potential of RK22 as an ideal treatment candidate against S. aureus infection.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Identification of RK22, a novel antimicrobial peptide from the salivary gland transcriptome of Hirudinaria manillensis, with MIC 6.25 ug/mL against MRSA. Demonstrates biofilm inhibition, plasma stability, low cytotoxicity, and in-vivo MRSA-clearance efficacy.

Leech-derived molecules this paper discusses, each with a full profile in the ASH compound registry:

Erfahren Sie, wie diese Forschung mit der klinischen Praxis verknüpft ist

More peer-reviewed studies in Speichel-Pharmakologie.

• Novel Leech Antimicrobial Peptides — Hirunipins — Kumar et al. (2025)
• 434 Salivary Proteins — Integrated Proteomics of Hirudo medicinalis — Liu et al. (2019)
• Medicinal Leech Genome Assembly — Anticoagulant Gene Catalog — Kvist et al. (2020)
• Effects of hirudotherapy on liver functions, lipid profile, and insulin sensitivity in rats with metabolic syndrome — Bilden A et al. (2026)
• Efficacy and Safety of Hirudotherapy for Improving Sperm Quality Parameters in Male Infertility: A Randomized Controlled Trial — Abtahi-Forooshani M et al. (2026)
• [Medicinal leeches and hirudotherapy] — Gödekmerdan A et al. (2011)
• PEROXIDATION OF SALIVA LIPIDS IN PATIENTS WITH POSTCOVID SYNDROME DURING HIRUDOTHERAPY — Serikbayeva S et al. (2024)
• Medicinal leech therapy in pain syndromes: a narrative review — Koeppen D, Aurich M, Rampp T (2014)
• Leech therapy in the treatment of a penile haematoma in a stallion — Nowicki A, Jaworska J, Baranski W (2021)
• Leech therapy (Hirudo medicinalis) attenuates testicular damages induced by testicular ischemia/reperfusion in an animal model — Davoodi F et al. (2021)

Browse all ASH-analysed research →