噬菌蛭弧菌具有裂解病原菌、净化水体的功效，从海洋环境中分离到4 株Bh04 系列蛭弧菌，对其生长条件进行了测定，同时研究了它们对61 株菌株的裂解能力。结果表明，在1%～3%的盐度范围内，蛭弧菌均可生长，最适盐度为3%！；在15～ 30！温度条件下蛭弧菌也可生长，但最适培养温度为20_25；只有在使用活的宿主菌的培养条件下，蛭弧菌才能生长。4株蛭弧菌分别可裂解21、24、4 0、43 株菌，各占总试验菌数（61）的344%、393%、656%和70 5%。4 株蛭弧菌一起，则可裂解55 菌株，占总试验菌株的902%。研究结果揭示了蛭弧菌在消除海洋环境中有害细菌方面的潜在应用价值。

噬菌蛭弧菌具有裂解病原菌的特殊功效，可以用作生物净化因子。本实验从海洋环境中分离到4 株Bh04系列蛭弧菌(Bh04-4, Bh04-41a, Bh04-A+ 和 Bh04-1f)。以41株弧菌为蛭弧菌的宿主菌，本文研究了蛭弧菌对海产品中常见弧菌的裂解消除能力，以探索其对由弧菌所引起的食物中毒等流行性传染疾病的预防效果。实验结果表明，41株弧菌中共有36菌株可被4株蛭弧菌(Bh04-4, Bh04-41a, Bh04-A+和Bh04-1f)中的任一株所裂解，占总试验菌株的87.8%；对副溶血弧菌、非01 非0139 群霍乱弧菌、溶藻胶弧菌这三种常见致病弧菌的裂解率分别达88.9%、83.3%、81.8%。本研究结果揭示了蛭弧菌作为生物消除剂在由弧菌所引起的食物中毒等流行性传染疾病的防治方面有潜在应用价值。

从海洋环境中分离出4 株蛭弧菌(Bdellovibrio sp.)，并对34 株九孔鲍 (Haliotis diversicolor) 苗细菌性病原进行了裂解试验。结果表明，Bh04-4、Bh04-41a、Bh04-A+和Bh04-1f 等4 株蛭弧菌分别可裂解11株、13 株、22 株和28 株病原菌裂解率为32.4%、38.2%、64.7%和87.5% 4；株共同作用则可裂解32 株病原菌，裂解率高达94.1%。研究结果展示了应用蛭弧菌控制九孔鲍苗细菌性病原的可行性。

Outbreaks of mass mortality among cultured postlarvae of abalone Haliotis diversicolor supertexta aged between 7 and 30 days occurred since 2002 on the south coast of China. Among 24 bacterial strains isolated from diseased abalone postlarvae on 2216E Marine and TCBS agar plates during an outbreak in July 2003, 23 were avirulent whilst a predominant strain (designated as strain 2) was highly virulent to postlarvae with an LD50 value under 1.0×103 colony forming units (CFU) ml−1. All the moribund/dead postlarvae exhibited the same gross symptoms as that observed in natural outbreaks. The same bacteria could be re-isolated from postlarvae after bacterial challenge using 2216E Marine and TCBS agar plates. API analysis identified it to be Vibrio parahaemolyticus with 99% confidence. 16S and ITS rDNA sequencing analysis also revealed it to be highly homologous with Vibrio parahaemolyticus. Kanagawa reaction and PCR amplification of TDH gene on strain 2 proved to be negative. Antibiotic susceptibility tests showed that strain 2 exhibited 56.25% of susceptibility to chemotherapeutic agents tested, and was resistant to penicillin G, amikacin, trimethoprim–sulfamethoxazole, tetracycline, ciprofloxacin, novobiocin and neomycin. Results in this study reveal that V. parahaemolyticus strain 2 is an infectious agent to abalone postlarvae in South China.

Outbreaks of serious mortality among cultured abalone postlarvae have occurred across Southern China since July 2002. Five motile bacterial strains were isolated from diseased abalone postlarvae on tryptic soy agar supplemented with 1% NaCl (TSA1) and/ or thiosulphate citrate bile salt (TCBS) sucrose agar plates during an outbreak in August 2003 in Shanwei, Guangdong province. All isolates were characterized and identi¢ed asVibrio alginolyticus on the basis of biochemical characteristics and comparisonswiththose of the reference strainV. alginolyticus ATCC 17749. Strain 19 (a representative of ¢ve similar isolates) was virulent to abalone postlarvae with an LD50 value of 1.00 104 colony-forming unitsmL 1. All abalone postlarvae exhibited the same signs as in natural outbreaks.The same bacterium could be re-isolated from abalone postlarvae after bacterial challenge usingTSA1andTCBS plates. The results reveal thatV. alginolyticus is an infectious agent of abalone postlarvae.

Mass mortality among the post-larvae of cultured abalone Haliotis diversicolor supertexta has occurred on the south coast of China since 2002. The diseased abalone are generally 10 to 30 days old, and typical signs of the disease include them turning white in colour and falling off the diatom films on which they were cultured. Among sixteen different motile bacteria isolated from the diseased post-larvae, four were identified as Vibrio parahaemolyticus on the basis of biochemical characteristics when compared with those of a V. parahaemolyticus type strain ATCC 17802T. Isolate 25, a representative isolate of V. parahaemolyticus recovered from diseased abalone, was virulent for the post-larvae with an LD50 value of 3.5 × 105 CFU (colony forming units)/ml. All moribund post-larvae artificially infected with the bacterium turned white and fell off the diatom films on which they were cultured as seen to occur during natural outbreaks of the disease, and it was possible to recover the bacterium from artificially infected post-larvae. The results of the study indicate that V. parahaemolyticus is a pathogenic bacterium to abalone post-larvae.

An epidemic of mass mortality of abalone (Haliotis diversicolor supertexta) postlarvae aged 40 days or less has existed across south coast of China since the second half of 2002. Among 20 bacterial strains isolated from diseased abalone postlarvae on 2216E marine agar plates during an outbreak of postlarval disease in August 2005, a predominant strain (designated strain 20) was demonstrated to be virulent to postlarvae with an LD50 value of 1.0-105 colony forming units (CFU ml 1) on day 4, while the other 19 strains were either avirulent (16 strains) or weakly virulent (3 strains). The same bacterium could be re-isolated from postlarvae after bacterial challenge using 2216E marine agar plates. Preliminary toxicity tests of ECPs of strain 20 revealed that at 2.77 mg protein ml 1, crude ECPs completely liquefied postlarvae within 24 h, leaving only shells. API 20E analysis identified strain 20 as Klebsiella oxytoca. 16S and ITS rDNA sequencing and phylogenetic analyses further confirmed this identification. Antibiotic susceptibility tests showed that strain 20 exhibited 94% of susceptibility to 16 various antibiotics tested and only showed resistance to streptomycin. Results of this work demonstrated that K. oxytoca is also linked to this epidemic in Fujian, China. This is considered to be the first report regarding K. oxytoca involved in the mass mortality of postlarval abalone in south China and the world.