US EPA

1224780 

Journal Article 

ANTIMICROBIAL ACTIVITY OF NATIVE SOUTH DAKOTA PLANT EXTRACTS ON ESCHERICHIA COLI 

Kafle, GN; Reese, N 

2010 

No 

Proceedings of the South Dakota Academy of Science
ISSN: 0096-378X 

89 (2010) 

264. 

Certain Escherichia coli (E.coli) are the primary cause of lethal diarrhea in weaned pigs. United States swine producers face huge losses due to bacterial infections. Our study was aimed mainly at investigating the antimicrobial effect of native South Dakota plants on E. coli for use as a source of new natural antibiotics. Some native plants have the potential to provide new classes of antibiotics with low cytotoxicity that may allow regional swine producers to protect young pigs from lethal diarrhea. We conducted our experiments by using twelve plants previously screened in our lab that had antimicrobial effects on E.coli. We treated E.coli with plant extracts from both dried as well as fresh plants. Our results indicate that fresh plant extracts were much more effective than those from dried plants. For our experiment, plant materials were extracted with methanol and dried by using a rotary evaporator and then resolubilized with 70% ethanol. Growth of E.coli was assayed using standard disk susceptibility tests and micro-dilution protocols. After determining Minimal Inhibitory Concentration (MIC), we plated cultures on blood agar Petri plates to determine whether the extracts were bactericidal or bacteriostatic. All experiments were conducted in triplicate. Out of the 12 plants collected in SD, only four, Clematis ligusticifolia, Monarda fistulosa, Centurea stoebe and Rhus aromatica showed strong enough antimicrobial effects in E.coli cultures to warrant further study. 

Plant protection; Cytotoxicity; Plant extracts; Antimicrobial agents; Rhus aromatica; Diarrhea; Antibiotics; Infection; Escherichia coli; Agar; Methanol; Antimicrobial activity; Ethanol; Monarda fistulosa; Minimum inhibitory concentration; Clematis ligusticifolia; Blood