Abstract：
BACKGROUND: Paenibacillus larvae is a spore-forming bacillus, the most important bacterial pathogen of honeybee larvae and the causative agent of American foulbrood (AFB). Control measures are limited and represent a challenge for both beekeepers and researchers. For this reason, many studies focus on the search for alternative treatments based on natural products.
OBJECTIVE: The objective of this study was to determine the antimicrobial activity of the hexanic extract (HE) of Achyrocline satureioides on P. larvae and the inhibitory activity on some mechanisms related to pathogenicity.
METHODS: The Minimum Inhibitory Concentration (MIC) of the HE was determined by the broth microdilution technique and the Minimum Bactericidal Concentration (MBC) by the microdrop technique. Swimming and swarming motility was evaluated in plates with 0.3 and 0.5% agar, respectively. Biofilm formation was evaluated and quantified by the Congo red and crystal violet method. The protease activity was evaluated by the qualitative technique on skim milk agar plates.
RESULTS: It was determined that the MIC of the HE on four strains of P. larvae ranged between 0.3 and 9.37 µg/ml and the MBC between 1.17 and 150 µg/ml. On the other hand, sub-inhibitory concentrations of the HE were able to decrease swimming motility, biofilm formation and the proteases production of P. larvae.
OBJECTIVE: The objective of this study was to determine the antimicrobial activity of the hexanic extract (HE) of Achyrocline satureioides on P. larvae and the inhibitory activity on some mechanisms related to pathogenicity.
METHODS: The Minimum Inhibitory Concentration (MIC) of the HE was determined by the broth microdilution technique and the Minimum Bactericidal Concentration (MBC) by the microdrop technique. Swimming and swarming motility was evaluated in plates with 0.3 and 0.5% agar, respectively. Biofilm formation was evaluated and quantified by the Congo red and crystal violet method. The protease activity was evaluated by the qualitative technique on skim milk agar plates.
RESULTS: It was determined that the MIC of the HE on four strains of P. larvae ranged between 0.3 and 9.37 µg/ml and the MBC between 1.17 and 150 µg/ml. On the other hand, sub-inhibitory concentrations of the HE were able to decrease swimming motility, biofilm formation and the proteases production of P. larvae.
摘要：
背景：类芽孢杆菌幼虫是一种孢子形成杆菌，蜜蜂幼虫最重要的细菌病原体和美国foulbrood（AFB）的病原体。控制措施是有限的，对养蜂人和研究人员都是一个挑战。出于这个原因,许多研究集中在寻找基于天然产物的替代疗法。
目的：本研究的目的是确定阿奇罗兰的六氢提取物（HE）对P.幼虫的抗菌活性及其对某些致病机制的抑制活性。
方法：通过肉汤微量稀释技术测定HE的最低抑菌浓度（MIC），通过微滴技术测定最低杀菌浓度（MBC）。在具有0.3和0.5％琼脂的平板中评估游泳和成群运动，分别。通过刚果红和结晶紫方法评估和定量生物膜形成。在脱脂乳琼脂平板上通过定性技术评估蛋白酶活性。
结果：确定HE对4种P.larvae的MIC在0.3至9.37µg/ml之间，MBC在1.17至150µg/ml之间。另一方面,亚抑制浓度的HE能够降低游泳运动，生物膜的形成和P。幼虫的蛋白酶产生。
目的：本研究的目的是确定阿奇罗兰的六氢提取物（HE）对P.幼虫的抗菌活性及其对某些致病机制的抑制活性。
方法：通过肉汤微量稀释技术测定HE的最低抑菌浓度（MIC），通过微滴技术测定最低杀菌浓度（MBC）。
结果：确定HE对4种P.larvae的MIC在0.3至9.37µg/ml之间，MBC在1.17至150µg/ml之间。
