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Journal of Integrative Agriculture  2026, Vol. 25 Issue (8): 3400-3411    DOI: 10.1016/j.jia.2024.12.026
Animal Science · Veterinary Medicine Advanced Online Publication | Current Issue | Archive | Adv Search |
Isopropoxy benzene guanidine: A promising new weapon against enterococcal infections

Jianxin Hu1, Yongxiang Zhang1, Jinyu Yang1, Sujuan Wu1, Weiqi Liu1, Yixing Lu1, 2, Wenguang Xiong1, Dongping Zeng1, Zhenling Zeng1#

1 College of Veterinary Medicine, South China Agricultural University/Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation/National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, Guangzhou 510642, China

2 Zhaoqing Academy of Agricultural and Forestry Sciences, Zhaoqing 526000, China

 Highlights 
● Isopropoxy benzene guanidine (IBG) kills a wide range of enterococci.
● IBG disrupts bacterial cell membranes.
● IBG cures skin infections caused by enterococci.
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摘要  

【目的】探究异丙氧苯胍(Isopropoxy benzene guanidine,IBG)对肠球菌的抗菌活性及抗菌机制,并在体内验证IBG的抗肠球菌活性。【方法】利用琼脂稀释法测定IBG对猫源、犬源和猪源肠球菌的最小抑菌浓度(Minimal inhibitory concentration,MIC)。使用ECOFFinder建立IBG对粪肠球菌和屎肠球菌的流行病学临界值。评估IBG对粪肠球菌和屎肠球菌的体外杀菌活性,并利用棋盘试验评估IBG与不同抗生素联用的效果。通过结晶紫法研究IBG亚抑菌浓度对粪肠球菌生物膜形成的影响。利用体外连续传代诱导试验,观察IBG对肠球菌抗菌作用的变化。为探究IBG的抗菌机制,利用不同荧光探针分别检测IBG作用下菌株膜电势、胞内pH、膜通透性和活性氧的变化;用分光光度法测定IBG作用下肠球菌胞内核酸和蛋白质泄露的水平;通过外源添加磷脂成分探讨其对IBG抗菌作用的影响。通过大蜡螟及小鼠皮肤感染模型,评估IBG的体内抗肠球菌活性。【结果】IBG对肠球菌的MIC范围为1-16 μg/mL,对粪肠球菌和屎肠球菌的流行病学临界值均为16 μg/mL。IBG的抗菌活性与其浓度呈正相关,4×MIC的IBG在8-12 h内能显著抑制肠球菌的生长,且IBG不易产生诱导耐药性。棋盘法试验表明IBG与所测抗生素联用均无协同作用。1/2×MIC的IBG可抑制粪肠球菌生物膜的形成。荧光探针试验表明,处理组的DiSC3(5)及PI的荧光强度与IBG浓度呈正相关。随IBG浓度增加,胞内核酸和蛋白质的泄漏水平也显著增加。外源添加128μg/mL的心磷脂,IBG对肠球菌的MIC值增加大于8倍。32μg/mL的IBG可显著提高大蜡螟的存活率,以及第10天小鼠皮肤的相对伤口面积率。【结论】IBG通过与磷脂酰甘油或心磷脂相互作用从而破坏细菌细胞膜,造成核酸及蛋白质的泄露,从而进一步加快细菌死亡。IBG具有体内外抗肠球菌活性,且不易产生诱导耐药,是治疗肠球菌感染的新武器。



Abstract  

The emergence of antibiotic resistance represents a significant threat to human health.  Human activities have accelerated the development of antibiotic resistance, underscoring the urgent need to develop novel antibiotics in addressing the challenge of antibiotic-resistant bacteria.  Isopropoxy benzene guanidine (IBG) is a substituted benzyl guanidine derivative with good antibacterial activity against enterococci.  In this study, the antibacterial activity of IBG against enterococci derived from dogs, cats, and pigs was evaluated (with a minimal inhibitory concentration range of 1–16 μg mL–1) and the epidemiological cut-off values (ECOFFs) were determined using ECOFFinder.  The ECOFFs for Enterococcus faecalis and Enterococcus faecium were both 16 μg mL–1.  The drug resistance development results showed that IBG has a low bacterial resistance risk.  The antibacterial mechanism studies showed that IBG disrupts bacterial cell membranes by interacting with phosphatidylglycerol or cardiolipin.  IBG inhibits the formation of E. faecalis biofilms, but it cannot eradicate them.  The results of the Galleria mellonella larvae infection model and mouse dermal infection model suggested that IBG has therapeutic effects on enterococcal infections in vivo.  In conclusion, IBG appears to be a good candidate for the treatment of enterococcal infections.

Keywords:  enterococci       isopropoxy benzene guanidine        antibacterial activity        antibacterial mechanism  
Received: 04 September 2024   Accepted: 02 December 2024 Online: 24 December 2024  
Fund: This work was supported by the National Natural Science Foundation of China (32273057).
About author:  Jianxin Hu, E-mail: 986651198@qq.com; #Correspondence Zhenling Zeng, E-mail: zlzeng@scau.edu.cn

Cite this article: 

Jianxin Hu, Yongxiang Zhang, Jinyu Yang, Sujuan Wu, Weiqi Liu, Yixing Lu, Wenguang Xiong, Dongping Zeng, Zhenling Zeng. 2026. Isopropoxy benzene guanidine: A promising new weapon against enterococcal infections. Journal of Integrative Agriculture, 25(8): 3400-3411.

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