注射鳖源致病性嗜水气单胞菌ZHYYZ-1引发中华鳖(Trionyx sinensis)稚鳖感染和致死的定量研究

QUANTITATIVE ANALYSIS OF INFECTION AND LETHAL EFFECTS ON JUVENILE TRIONYX SINENSIS BY INJECTING PATHOGENICENIC AEROMONAS HYDROPHILA ZHYYZ-1

以20日龄中华鳖稚鳖为实验动物,采用静水停食实验法,在水温(27.4±1.3)℃、pH7.1条件下,进行了注射鳖源嗜水气单胞菌ZHYYZ-1引发中华鳖稚鳖感染和致死的定量实验研究。结果表明:(1)该菌为高致病性菌株,异常排泄是该菌致稚鳖表露临床感染症状的重要标志;(2)注射该菌引起稚鳖感染与致死具明显的剂量—时间效应,随注射菌量递增依次出现不表露临床感染症状、表露临床感染症状而不出现死亡和大量死亡三种情形,稚鳖表露临床感染和出现死亡的时间均随注射菌量增大而明显缩短,绝大多数稚鳖表露临床感染和出现死亡的时限分别为2h和48h;(3)濒死稚鳖体内该菌的底限含量为3.3×106CFU/g,稚鳖体内菌注射含量可控安全范围为(1.2—8.8)×103CFU/g。

Quantitative analysis of infection and lethal effects on juvenile Trionyx sinensis was studied in the standing water without feeding at（27.4±1.3）℃ by injecting pathogenicenic Aeromonas hydrophila named ZHYYZ-1,which was isolated from the same species of turtle.It was found that：（1） the bacteria strain isolated from the infected turtle was a pathogenic,leading to abnormal excretion;（2） the infection and lethal effects were dose-and time-dependent.There were 3 types of symptoms after the injection,depending on the increases of the amount of bacterial injected：no clinical infection,clinical infection but caused no death,clinical infection caused mass death;（3） the times when the young turtle showed clinical infection symptoms（2h） and death（48h） had a negative correlation with the increases of the amount of bacterial injected;（4） the lowest amount of pathogenic bacterial in impending death turtle was 3.3×106 CFU/g,and the safe range of bacterial number in a turtle was between 1.2×103 CFU/g to 8.8×103 CFU/g.