China Animal Husbandry and Veterinary Medicine ›› 2023, Vol. 50 ›› Issue (1): 328-340.doi: 10.16431/j.cnki.1671-7236.2023.01.033

• Basic Veterinary Medicine • Previous Articles     Next Articles

Study on Bacteriostatic Action of Aqueous Extract of Granati pericarpium Against Multi-drug Resistant Escherichia coli of Swine

LIU Lin1,2, WU Baoqing1, GUO Xiaoyin1, YU Wenhui2, TIAN Lang3,4   

  1. 1. Animal Husbandry and Fisheries Research Center of Guangdong Haid Group Co., Ltd., Guangzhou 511400, China;
    2. College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China;
    3. Guangdong Haid Animal Husbandry and Veterinary Research Institute Co., Ltd., Guangzhou 511400, China;
    4. Guangdong Provincial Enterprise Key Laboratory of Pig Raising and Swine Disease Control Technology, Guangzhou 511400, China
  • Received:2022-08-16 Online:2023-01-05 Published:2023-01-04

Abstract: 【Objective】 The aim of this study was to obtain Escherichia coli (E.coli)strains carrying virulence genes and multi-drug resistance from diarrheic piglets, and evaluate the antibacterial activity of aqueous extract of Chinese herbal medicine against multi-drug resistant E.coli, and explore the antimicrobial mechanism.【Method】 The enterotoxin genes and drug resistance of clinical E.coli isolates were measured with PCR and Kirby-Bauer (K-B) disk diffusion method, respectively.Antibacterial activity of Chinese herbal medicine against multi-drug resistant E.coli was evaluated through broth microdilution method, and then minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of aqueous extract of Chinese herbal medicine were obtained.After aqueous extract of Granati pericarpium exposure for different time, the conductivity meter and related detection kits were used to evaluated the changes of conductivity and alkaline phosphatase (AKP) content in bacterium solution, and intrabacterial ATP content.Intrabacterial soluble proteins changes were examined by SDS-PAGE and protein content detection, and then morphological changes of E.coli were visualized using scanning electron microscopy.【Result】 The prevalence of enterotoxin genes reaches 78.57% in 14 isolated clinical E.coli strains in PCR detection.Antibiotic-susceptibility testing results showed that all strains were resistant to at least two antibiotics, and all belonged to multi-drug resistant strains.The results of Chinese herbal medicine susceptibility testing showed the better antibacterial activity of aqueous extracts of Coptidis rhizoma, Scutellariae radix and Granati pericarpium against multi-drug resistant strains, among which the MIC and MBC values of Granati pericarpium were 31.25 and 62.5 mg/mL, respectively.Aqueous extract of Granati pericarpium could inhibit growth and reproduction of multi-drug resistant and quality control strains at concentrations of 1/2MIC or MIC.Within 3 h post-stimulation of aqueous extract of Granati pericarpium, conductivity of bacterial solution was extremely significantly increased compared with control group (P<0.01).During 6 h treatment of aqueous extract of Granati pericarpium, the results of AKP and ATP detections showed that AKP content in bacterial solution in treated group was extremely significant higher than control group (P<0.01), and intrabacterial ATP content was extremely significantly lower than control group (P<0.01).The results of SDS-PAGE and protein content detection showed that intrabacterial soluble proteins were decreased with the increase of action time.The results of scanning electron microscopy showed fragmentation and lysis in aqueous extract of Granati pericarpium-treated E.coli.【Conclusion】 The present study demonstrated that aqueous extract of Granati pericarpium could significantly inhibit growth of multi-drug resistant E.coli with enterotoxin genes, which provided theoretical reference and drug development basis for clinical treatment of piglet diarrhea infected by multi-drug resistant E.coli.

Key words: drug resistance; Escherichia coli; aqueous extract of Granati pericarpium; antimicrobial mechanism

CLC Number: