ABSTRACT
OBJECTIVE: To evaluate the antimicrobial efficacy of berberine, a plant alkaloid. METHODS: Five multi-drug resistant (MDR) STEC/EPEC and five MDR ETEC isolates from yaks with haemorrhagic diarrhoea were selected for the study. Antibacterial activity of berberine was evaluated by broth dilution and disc diffusion methods. The binding kinetics of berberine to DNA and protein was also enumerated. RESULTS: For both categories of enterovirulent Escherichia coli (E. coli) isolates, berberine displayed the antibacterial effect in a dose dependent manner. The MIC(50) of berberine chloride for STEC/EPEC isolates varied from 2.07 µM to 3.6 µM with a mean of (2.95 ± 0.33) µM where as for ETEC strains it varied from 1.75 to 1.96 µM with a mean of (1.87 ± 0.03) µM. Berberine bind more tightly with double helix DNA with Bmax and Kd of (24.68±2.62) and (357.8±57.8), respectively. Berberine reacted with protein in comparatively loose manner with Bmax and Kd of (18.9±3.83) and (286.2±113.6), respectively. CONCLUSIONS: The results indicate clearly that berberine may serve as a good antibacterial against multi drug resistant E. coli.
Subject(s)
Anti-Bacterial Agents/therapeutic use , Berberine/therapeutic use , Cattle Diseases/drug therapy , Diarrhea/drug therapy , Escherichia coli Infections/drug therapy , Animals , Berberine/metabolism , Cattle , DNA, Bacterial/metabolism , Diarrhea/veterinary , Drug Resistance, Multiple, Bacterial , Enteropathogenic Escherichia coli , Enterotoxigenic Escherichia coli , Escherichia coli Infections/veterinary , Microbial Sensitivity Tests , Protein Binding , Shiga-Toxigenic Escherichia coliABSTRACT
Of 273 samples (rectal swab) collected from free-ranging yaks of Tawang district, Arunachal Pradesh, 42 Shiga toxin-producing Escherichia coli (STEC), six enteropathogenic E. coli (EPEC) and 27 enterotoxigenic E. coli (ETEC) strains were isolated. All the STEC and EPEC strains were further investigated for respective stx variants (for STEC only) and additional putative virulence factors. The 27 ETEC strains were also screened for characteristic enterotoxin gene(s) and colonization factors. Occurrence of ETEC was significantly (p < 0.05) higher in the diarrheic yaks and yaks of less than 1 year of age. Majority of enterovirulent E. coli isolates were resistant to amikacin, azithromycin, chloramphenicol, colistin, doxycycline, furazolidone, nalidixic acid, nitrofurantoin, streptomycin and tetracycline. Dendrogram, constructed with molecular fingerprinting profiles obtained from RAPD (Randomly Amplified Polymorphic DNA) and ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR, placed the isolates in different clusters irrespective of their serotypes, virulence gene and drug resistance pattern. Collectively, the study indicates that yaks, being a potential reservoir of multidrug resistant STEC and EPEC, may represent significant risk to public health in this region. Higher recovery of ETEC isolates from yaks with diarrhea points out that ETEC may be a major determinant for repeated occurrence of diarrhea in yaks.
