Efficacy of medicinal plant extracts and antimicrobials on different serotypes of Escherichia coli

Abstract

Ethanolic extracts of 7 different medicinal plants used in folk medicine in Sikkim, India, and 16 different commercially available antimicrobial agents were investigated by using disc diffusion method for their antimicrobial activity against 25 different strains of Escherichia coli isolated from milk of dairy cattle and yak, and faeces of diarrhoeic calves and goats. E. coli were serotyped into 12 different somatic ‘Ö’ serogroups and three untypable strains. All these isolates showed sorbitol fermentation except O157 and 2 untypable strains. Enterohemorrhagic strains (O26 and O157) isolate both from diarrhoea and mastitis milk samples indicated that these might be the cause of intramammary inflammation as well. Amongst antimicrobials, highest sensitivity was recorded against sparfloxacin and ciprofloxacin (100% each) followed by nitrofurantoin (92%) and chloramphenicol (88%). Highest antimicrobial property was observed in the extract of Eupatorium cannabium, Astilbe rivularis and Schima wallichi in comparison to Artemisia vulgaris, Aloe barbadensis and Kaempferia rotunda. It is concluded that extracts of some medicinal plants and commercial antimicrobials showed sensitivity against different serotypes of E.coli.