Iwata Taketoshi, Une Yumi, Okatani Alexandre Tomomitsu, Kato Yukio, Nakadai Aya, Lee Ken-Ichi, Watanabe Maiko, Taniguchi Takahide, Elhelaly AbdelAzim Elsayed, Hirota Yoshikazu, Hayashidani Hideki
Division of Animal Science, Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan.
Vet Microbiol. 2008 Jun 22;129(3-4):404-9. doi: 10.1016/j.vetmic.2007.11.029. Epub 2007 Dec 4.
Between April 2001 and 2007, 18 Yersinia pseudotuberculosis outbreaks occurred in breeding monkeys at 12 zoological gardens in Japan, and 28 monkeys of 8 species died. A total of 18 Y. pseudotuberculosis strains from the dead monkeys, comprising one strain per outbreak, were examined for serotype and the presence of the virulence genes virF, inv, ypm (ypmA, ypmB and ypmC) and irp2. Of the 18 Y. pseudotuberculosis strains, 7 (38.9%) were serotype 4b, 7 (38.9%) were serotype 1b, and there was one each of serotypes 2b, 3, 6 and 7. All the 18 strains examined harbored virF and inv. Sixteen (88.9%) strains, including the strain of serotype 7, harbored ypmA. However, no strain harbored ypmB, ypmC and irp2. This study demonstrated that among other pathogenic factors, almost all the Y. pseudotuberculosis isolated from the outbreaks had the ypm gene encoding the superantigenic toxin, YPM. As most of the monkeys who died in those outbreaks originated from South America and other regions, where the presence of the ypm gene have not been reported, YPM might be the cause, or at least the most important factor for, the high mortality of the breeding monkeys infected by Y. pseudotuberculosis in Japan. This is also the first report of a fatal case due to Y. pseudotuberculosis serotype 7 infection in the world.
2001年4月至2007年期间，日本12家动物园饲养的猴子中发生了18起假结核耶尔森菌疫情，8个物种的28只猴子死亡。对从死亡猴子身上分离出的总共18株假结核耶尔森菌菌株（每次疫情1株）进行了血清型检测，并检测了毒力基因virF、inv、ypm（ypmA、ypmB和ypmC）和irp2的存在情况。在这18株假结核耶尔森菌菌株中，7株（38.9%）为血清型4b，7株（38.9%）为血清型1b，血清型2b、3、6和7各有1株。所检测的18株菌株均携带virF和inv。包括血清型7的菌株在内，16株（88.9%）菌株携带ypmA。然而，没有菌株携带ypmB、ypmC和irp2。本研究表明，在其他致病因素中，从疫情中分离出的几乎所有假结核耶尔森菌都具有编码超抗原毒素YPM的ypm基因。由于在那些疫情中死亡的大多数猴子原产于南美洲和其他地区，而这些地区尚未报道ypm基因的存在，YPM可能是导致日本感染假结核耶尔森菌的繁殖猴子高死亡率的原因，或者至少是最重要的因素。这也是世界上首例由假结核耶尔森菌血清型7感染导致的致命病例报告。
