Abstract:

Staphylococcus aureus （S. aureus） and the small colony variants （SCVs） infection are considered as main issues affect livestock and poultry health. However， there are still many challenges in persistent and recurrent infections， and even drug resistance for treatment of traditional antibiotics.The antimicrobial peptide PAJE has the broad-spectrum antibacterial activity. To study the mechanisms of peptide PAJE against S. aureus and SCVs， the antibacterial activity， stability and biological characteristics were determined. The results indicated that the antibacterial peptide PAJE had a penetration ability to destruct bacterial cell wall， even permeated 54.7% and 62.9% cell membrane. Additionally， the peptide PAJE could also up-regulate the Agr regulatory system genes， down-regulate the SigB regulatory system and biofilm forming related genes， which greatly inhibited biofilm formation. In addition， higher temperature and pH stability made PAJE better processing， storage， and environmental tolerance. In conclusion， the antimicrobial peptide PAJE could be a potential candidate peptide for the treatment of S. aureus， SCVs and their biofilm infections， which provided theoretical support for the development of reduce and replace antibiotics products.

Key words: Staphylococcus aureus, SCVs, antimicrobial peptide PAJE, biofilm

摘要：

金黄色葡萄球菌（Staphylococcus aureus）及其小菌落突变体（small colony variants，SCVs）感染是影响畜禽健康的主要问题。然而，传统抗生素治疗面临持续和复发性感染以及耐药性等许多挑战。抗菌肽PAJE具有广谱抗菌性，为深入探究抗菌肽PAJE的生物学特性及其对S. aureus和SCVs杀菌作用机制，对其抗菌活性、稳定性、生物学特性进行测定。结果表明，抗菌肽PAJE对S. aureus和SCVs细胞膜渗透力达54.7%和62.9%，同时通过上调Agr调控系统、下调SigB调控系统及生物膜相关基因的表达，从而极大程度地抑制生物膜形成。此外，较高温度及pH稳定性为抗菌肽PAJE提供了更好的加工、存储和环境耐受性。综上所述，抗菌肽PAJE可作为治疗S. aureus和SCVs及其生物膜感染的潜在候选肽之一，为替抗减抗类产品研发提供理论支撑。

关键词: 金黄色葡萄球菌, 小菌落突变体, 抗菌肽PAJE, 生物膜