An Investigation into the Inhibitory Effect of Hydroalcoholic Extract of Zataria multiflora Boiss (Shirazithyme) on Escherichia Coli isolated from calveswith Diarrhea in Kazerun

Diarrhea in calves is one of the most prevalent diseases the veterinarians encounter in practice. Diarrhea is responsible for major economic damages in livestock husbandries. Escherichia coli (E.coli) has been regarded as the main factor that causes calves diarrhea in their first three weeks of life. White diarrhea in calves is caused by certain serotypes of E.coli. The excessive use of antibiotics has led to the multiple drug resistance in most bacterial pathogens. The development of drug resistance in pathogens has led to the emergence of new and natural antimicrobial agents.This descriptive cross-sectional study was carried out to investigate the effect of hydroalcoholic extract of Shirazi thyme on 100 samples of calves with diarrhea collected from traditional and industrial livestock husbandries crops in Kazerun during February and March 2016 and April 2017. The enrichment media, Selenite F Broth and Mac Conkey Agar (Mac) were used. To evaluate the lactose fermentation and to determine the identity of isolated bacteria, Eosin Methylene Blue agar(EMB) was used.The antibiogram test also demonstrated that isolated strains were susceptible to most antibiotic groups used in the treatment of diarrhea. In this study, all isolated strains showed resistant against antibiotics as ampicillin and tetracycline, and were susceptible to antibiotics such as streptomycin, gentamicin, nalidixicacid,cefixime, ciprofloxacin, nitrofurantoin and chloramphenicol.The halo diameter formed by hydroalcoholic extract of Shirazi thyme was 8mm,demonstrating a low susceptibility of this bacterium to the hydroalcoholic extract of Shirazi thyme. In general, the findings indicate that the hydroalcoholic extract of Shirazi thyme has few antimicrobial properties and much more studies are required to achieve better results.