Study On The Application Of Vibrio Fischeri And Vibrio Qinghaiensis In Antibiotics Detection

By cultivating two kinds of bioluminescent bacteria-vibrio fischeri and vibrio qinghaiensis,the fresh bacteria suspension was prepared,we detected the toxicity of fosfomycin, pefloxacin mesylate,and cliimycin,moreover,we had researched the best determining temperature,the best cultivation time,the storage character of these two kinds of bioluminescent bacteria,and determining cliimycin in milk.The results are as follows:1.The best detecting temperature Under 25℃,RUL of vibrio qinghaiensis declined linearly, vibrio fischeri reduced with power function model,however,under other temperature,the tendency of RLU decline was not regular,so it was better to determine antibiotics under 25℃by using vibrio qinghaiensis and?vibrio fischeri.2.The best cultivation timeAfter cultivating? vibrio qinghaiensis for 10h,its character of bioluminescence was not steady enough,and during 14-18h of cultivation, the performance became better,especially after 14h,and exposed to cliimycin for 50min,the correlation coefficient of dose-respones relationship was 0.9996,well after 22h,this bacteria became too weak to determine cliimycin precisely.On the contrary,the bioluminescence of vibrio fischeri became steady enough to determine cliimycin until 22h of cultivation.3.Detection of three kinds of antibiotic in water:It showed that fosfomycin exerted toxic effect on Vibrio qinghaiensis quickly,after 30min exposure time,?the inhibition effect of such antibiotic with concentration of 10μg/L to 100μg/L were over 80%,the dose-respones relationship was not good though.Such relationship toward vibrio fischeri was good for pefloxacin mesylate,but its E₅₀ fluctuated too much.For cliimycin,its dose-respones relationship toward both of Vibrio qinghaiensis and vibrio fischeri was good,it exerted excitotoxicity to Vibrio qinghaiensis within 20min,the dose-respones relationship came to be best at 50min,? R²=0.9996,the E₅₀ declined a lot with exposure time,from 57.16μg/L at 30min to 18.47μg/L at 70min. Cliimycin exerted inhibition effect to vibrio fischeri with linear tendency vs the antibiotic concentration,such relationship was steady, and E₅₀ fluctuated near 60μg/L.4.The comparison of storage character between these two kinds of bioluminescent bacteria:During 96h under 4℃, E₅₀ of cliimycin to vibrio fischeri fluctuated near 60.1μg/L,and its coefficient of variation was relatively small(within 5% before 24h of storage). The dose-respones relationship of cliimycin was also good,especially the bacteria suspension made by that very day,and the average of correlation coefficient between dose-respones relationship was 0.9824,its cv was 0.81.On the contrary,the storage character of vibrio qinghaiensis was worse,the average of E₅₀ declined from 74.30μg/L on the very day to 37.20μg/L 24h later.5.Determine cliimycin in milk:The patterns of cliimycin inhibition effect on these two kinds of bioluminescent bacteria were similar,and such patterns were steady with time,and the dose-respones relationship toward vibrio fischeri was much more steady compared with vibrio qinghaiensis.RLU of vibrio fischeri was higher than vibrio qinghaiensis(the former only needed 3.5μl bacteria suspension,and the latter needed 10μl),and the luminescence of the former was much more intensive in milk than that in water,in the same time such luminescence got higher with time in milk,however,this change was regular.Generally speaking, the performance of vibrio qinghaiensis in determing cliimycin inhibition effect in milk was better than that of vibrio qinghaiensis.Countless kinds of bioluminescent bacteria wide spread over the world,they are sensitive to most of the pollution.Especially,vibrio bioluminescent bacteria has become one of the important microorganisms which were used in estimating the harm of veterinary medicine residue in animal food and environment.In term of primary screening,?bioassays has become a essential method of estimating relative hazard.In this program,we have further studied the application of vibrio qinghaiensis and vibrio fischeri in antibiotic detection.