Evidence that the causal agent of bacterial cold-water disease Flavobacterium psychrophilum is transmitted within salmonid eggs
Evidence that the causal agent of bacterial cold-water disease Flavobacterium psychrophilum is transmitted within salmonid eggs
复制标题
DOI：
10.3354/dao029213
复制
发表时间：
1997-06-19
影响因子：
1.4
通讯作者：
Levine, RP
中科院分区：
文献类型：
--
作者：
Brown, LL;Cox, WT;Levine, RP
为了研究引起细菌性冷水病（BCWD）的嗜冷黄杆菌（Flavobacterium psychrophilum）垂直传播的可能性，从17条虹鳟鱼中采集了处于选定发育阶段的卵和胚胎。用于本研究的一些亲鱼刚头鳟鱼在产卵前注射了红霉素;一些注射了土霉素，另一些没有注射。将表面消毒的蛋/胚胎在胰蛋白胨酵母提取物（TYE）肉汤中孵育，并且当在17 ° C孵育72小时后没有从肉汤中分离出细菌时，确定蛋表面是无菌的。然后将这些卵/胚胎均质化并在TYE肉汤中培养，并将生长鉴定为F。通过生化和免疫学分析鉴定嗜冷菌。F.从28%的卵/胚胎表面鉴定出嗜冷菌污染。F.在10%的亲鱼的卵巢液样品中也检测到嗜冷菌，并且从13%的新产卵的表面消毒的卵的内容物以及从7%的有眼卵和4%的新孵化的卵中分离出该细菌。感染F.嗜冷菌从南极注射与非注射鱼。然而，在孵化场，注射红霉素的亲鱼的剩余后代经历了显着降低死亡率，由于BCWD高达10周后，挂起比鱼的后代不注射或注射土霉素。离体实验表明，F.嗜冷菌对浓度高达2 mg/ml（大于鲑卵内发现的浓度）的溶菌酶具有抗性，而2%的F.嗜冷菌细胞在100 ppm聚维酮/碘暴露30 min后存活。嗜冷菌可以在鲑鱼孵化场内水平和垂直传播。
To examine the possibility that Flavobacterium psychrophilum, cause of bacterial coldwater disease (BCWD), may be vertically transmitted, eggs and embryos at selected stages of development were taken from 17 steelhead trout. Some of the broodstock steelhead trout used for this study had been injected with erythromycin prior to spawning; some had been injected with oxytetracycline, and others had not been injected. Surface disinfected eggs/embryos were incubated in tryptone yeast extract (TYE) broth, and egg surfaces were determined to be sterile when no bacteria were isolated from the broth after 72 h incubation at 17 degrees C. These eggs/embryos were then homogenized and cultured in TYE broth, and growth was identified as F. psychrophilum by biochemical and immunological assays. F. psychrophilum contamination was identified from the surface of 28% of eggs/embryos. F. psychrophilum was also detected within the ovarian fluid samples from 10% of the broodstock trout, and the bacterium was isolated from the contents of 13% of newly spawned, surface-disinfected eggs as well as from 7% of eyed eggs and 4% of newly hatched alevins. No difference was observed in the proportion of eggs infected with F. psychrophilum from antibiotic-injected versus non-injected fish. At the hatchery, however, the remaining progeny of broodstock injected with erythromycin experienced significantly lower mortality due to BCWD up to 10 wk after pending than the progeny of fish not injected or injected with oxytetracycline. In vitro experiments indicated that F. psychrophilum is resistant to lysozyme concentrations of up to 2 mg ml(-1) (greater than concentrations found within a salmonid egg) and that 2% of F. psychrophilum cells survive after exposure of 100 ppm povidone/iodine for 30 min. The results of this study indicate that F. psychrophilum may be transmitted both horizontally and vertically within salmonid hatcheries.