The Effect Of Temperature And Chinese Medicine On Streptococcus Agalactiae

China is the largest tilapia cultivation country around the world and its tilapia production reached 1.6985 million tons in 2014, which accounting for about 32% of the world's tilapia production.Streptococcicosis caused by Streptococcus agalactiaedidgreat damage to tilapia aquaculture industry in recently years. In order to reduce the loss ofstreptococcicosisand avoid the abuse of antibiotics which will give rise to drug resistance and residuces,we studied the effects of temperature on the drug resistance of S. agalactiaeand screened detoxicating Chinese herbal medicine for the control ofS. agalactiaefrom tilapia. Then, the clinical efficacy of the screened Chinese herbal medicine on controlling the streptococcicosisfor tilapia culture. The results of this study will lay the foundation for the safe and efficientcontrol of streptococcicosisin tilapiaThe occurrence of streptococcicosis in tilapiais closely related to the environmental temperature. In order to explore the influence of temperature on the antibiotics resistance of S. agalactiae, NCCLS sensitivity test method was used to test the antibacterial activity of 21 antibiotics on four bacterial strains isolated from Hainan province and one standard strain bought from CICC under different incubate temperatures (25 ?, 30 ? and 37 ?) . Then, the significance of difference oftheinhibitionzonediameters were analyzed byturkey multiple comparison test.The results showed that penicillin, carbapenems and macrolide antibiotics were sensitive to all the tested bacterial strains incubated at 25 ?, 30 ? and 37 ?. However, except tobramycinandchemitrim resistant to all experimental strains (all of theinhibitionzone diameter is zero), the antibacterial activities of the remain 19 experimental antibiotics were affected in different degrees by the experimental temperatures. In all the inhibition zone diameters which were significantly affected by temperature, the proportion ofthe biggest inhibition diameters incubated under 25 ?, 30 ? and 37 ?were 43.8%, 35.6% and 20.6%, respectively.; and the proportion of the minimum inhibition diameters incubated under 25?, 30? and 37? were 37.0%, 37.0% and 26.0%,respectively.In order to explore the high efficiency and cheap new medicine of tilapia S.agalactiae, four bacterial strains isolated from Hainan province and one standard strain bought from CICC as our research object were used to screen vitro effective Chinese herbal medicine through 96-well micro well platewith double layer agar diffusion method. Then, the screened and most effective Chinese herbal medicine mixed with fodder were fed to the artificial inffected tilapia ofS. agalactiaeand thus its efficiency was knowned. The results showed thatthe inhibition rate over 10% of micro well plate preliminary screened of Chinese herbal medicine, we obtained 9 kinds of Chinese herbal medicine extracted by ethanol and 25 kinds of Chinese herbs extracted by water extraction. The effective Chinese herbal medice premilimary screened were tested by agar diffusion method to get the diameter of inhibition zone.Phellodendron,Rabdosiarubescens and Cyrtomium extracted by ethanol were 333mg/ml and their diameter of inhibition zone were 13.83?19.4mm?8.99?15. lmmand 7.53 ?9.37mm repectively; phellodendron, Gynostemma,Polygonumand Pomegranate Peelextracted by waterwere 150 mg/ml and their diameter of inhibition zone were 10.67?15.8mm, 6.33?6.54mm (PBSA1502 resistance), 6.26mm(QH726, PBSA1504and PBSA1502 resistance)and 6.23?7.34mm respectively. Thus, the Phellodendron extracted by ethanol was the most effective medicine aganst the S. agalactiaein vitro. The protective rate of 20g/kg Phellodendron extracted by ethanol in treatment of artificial infected S, agalactiae was 30.3%.