温度对罗非鱼无乳链球菌抗菌药物敏感性的影响

Effects of Temperature on Antibiotics Susceptibility of Streptococcus agalatiae from Tilapia

为研究温度对罗非鱼无乳链球菌(Streptococcus agalactiae)抗菌药物敏感性的影响,以无乳链球菌CICC10465及4株从海南分离的罗非鱼无乳链球菌作为供试菌,采用显微计数法测定了供试菌在25,30和37℃下培养18 h后的菌体浓度,并采用NCCLS药敏纸片法测定了21种抗菌药物在此3个温度下对供试菌抑菌圈直径的影响,并对各条件下的抑菌圈直径进行了差异性分析.结果表明,除了PBSA1502之外的4株供试菌,其生长均受温度显著影响,在任一测试温度下各供试菌对青霉素类抗菌药物均敏感,对碳青霉素类和大环内酯类抗菌药物亦敏感或中介;16种抗菌药物对3株以上供试菌的抑菌圈直径受温度显著影响;不同抗菌药物对不同供试菌株的抑菌圈直径受温度的影响趋势和程度不同.

To investigate the effects of temperature on the antimicrobial agent susceptibility of Streptococcus agalatiae from tilapia,S. agalactiae CICC10465 and other 4 S. agalatiae strains isolated from Hainan province were used as the test bacteria. The microscopic counting method was used to determine the concentrations of the test bacteria after being cultured at 25,30,and 37 ℃ for 18 h. Then,NCCLS method was used to determine the inhibition zone diameters of 21 antimicrobial agents to the test bacteria at the 3 temperatures,respectively. The differences of the concentrations of the test bacteria being cultured at the 3 temperature were tested,and the differences of the diameters of the inhibition zones of 21 antimicrobial agents to the test bacteria were also tested.The results showed that except strain PBSA1502,the growths of the other 4 test bacteria were significantly affected by temperature. At either test temperature,all test bacteria were susceptible to penicillin＇s antimicrobial agents,intermediate or susceptible to carbapenems and macrolide. The diameters of the inhibition zones of 16 antibacterial agents to more than 3 test bacteria were affected by the culture temperature significantly. Due to the different bacterial strains and antibacterial agents,the influences trends and degrees of the temperature on the diameters of the inhibition zones were different.