Dr.
Nobuyuki Kijima
Institute of Food Research, National Agriculture and Food Research Organization, Tsukuba, Japan
Title of the talk: Antimicrobial resistance in conventionally grown lettuce
Abstract
Sir Alexander Fleming’s discovery of penicillin in 1928 was a new beginning in the treatment of infectious diseases. Currently, antibiotics are used in variety of applications and account for almost 60 % of total consumption during food production, meat, eggs, fisheries, and crops in Japan. The reduction measures of antibiotic treatment have been started based on scientific knowledge in animal husbandry and aquaculture. On the contrary, the impact of the application of antibiotics as agricultural chemicals to crop field is not well known. Application of human-applicable antibiotics, streptomycin, SM or oxytetracycline, OTC as agricultural chemicals to control bacterial plant pathogens is available to grow lettuce in Japan. So, we observed the prevalence of antibiotic-resistant bacteria of the lettuce, that is conventionally grown in spring, by culture dependent methods and DNA analysis of 16S rRNA sequence. Population of bacteria on the surface of lettuce was 5 Log CFU/g on non-selective agar medium, R2A, 4 Log CFU/g on selective agar medium, R2A with SM (40mg/L), 3 Log CFU/g on R2A with OTC (40mg/L) and 4 Log CFU/g on R2A with aminobenzylpenicillin, ABPC (40mg/L) at 25-degree C. There were 16 genera in arbitrarily isolated 100 strains of bacteria on non-selective agar medium from 16S rRNA analysis. In case of selective agar medium, there were 11 genera on medium with SM, eight genera on medium with OTC and eight genera on medium with ABPC and they were common soil bacteria but not pathogenic genus against human. Resistance in isolated bacteria to SM or ABPC was higher level on the surface of the lettuce leaves. These results may suggest that resistance to SM or ABPC is general property in bacteria on the lettuce leaves. And some bacteria might harbor resistant genes to both SM and ABPC.
Biography
Nobuyuki Kijima has completed his PhD at Tokyo Institute of Technology and postdoctoral studies from Research Institute of Innovative Technology for the Earth. He is the principal scientist of Institute of Food Research, National Agriculture and Food Research Organization organization.
Publications: Researchgate