CHARACTERIZATION OF CHRONIC, ASYMPTOMATIC INTESTINAL SHE

这些研究旨在利用志贺菌的特异性毒力基因片段作为DNA探针或其序列信息在聚合酶链反应中检测粪便中的志贺菌。我们的早期研究表明，DNA探针在检测秘鲁腹泻病患者粪便中的志贺菌时非常敏感、快速和有效。在最近利用聚合酶链反应分析健康（即无症状）非人灵长类动物及其健康人类照顾者粪便的研究中，我们发现慢性、低水平（即低于细菌学检测）无症状志贺氏菌携带率很高。我们的具体目标是确定（1）这些志贺氏菌是否具有完全的毒力潜力，（2）志贺氏菌在人类或灵长类动物携带者中的确切状态（例如，在结肠的粘膜上皮细胞内？），(3)带菌者对志贺氏菌的免疫状态，以及（4）这种慢性低水平带菌者状态是否是维持志贺氏菌在美国流行的原因，美国现在每年有超过25，000例志贺氏菌。

These studies are directed at utilizing specific virulence gene regions of Shigella as DNA probes or their sequence information in polymerase chain reaction assays to detect Shigella in stools. Our early studies showed that DNA probes were very sensitive, quick, and effective in detecting Shigella in the stool of diarrheal disease patients in Peru. In more recent studies utilizing polymerase chain reaction analysis of stools of healthy (i.e. asymptomatic) nonhuman primates and their healthy human caretakers, we have found a high rate of chronic, low level (i.e. below bacteriologic detection) asymptomatic carriage of Shigella. Our specific objectives are to determine (1) if these Shigella have full virulence potential,(2) the exact state in which Shigella are residing in human or primate carriers( e.g. inside mucosal epithelial cells in the colon?), (3) the immune status of the carrier to Shigella, and (4) if this chronic low level carrier state is responsible for maintaining Shigella endemicity in the U.S. where there are now over 25,000 cases per year.