Biological, Epidemiological and Clinical Studies on Amebic Infection among Institutionalized Populations

对溶组织内阿米巴感染率较高的住院人员进行了流行病学和临床研究。对这些个体的阿米巴分离株也进行了生物学分析。流行病学分析表明，特异性抗原检测方法和常规粪便检查的阳性率高达30%。然而，大多数感染似乎是由于溶组织芽胞杆菌的持续无症状感染。从这些持续感染的个体中分离的几株溶组织芽胞杆菌表现出与溶组织芽胞杆菌一致的遗传和抗原特性；然而，用灵敏的荧光方法检测，它们确实对组织培养的细胞几乎没有毒力。基于几丁质酶基因等4个不同基因的碱基多态性，建立了溶组织芽孢杆菌亚群遗传类型的鉴定，并应用于多家机构的分离菌株。分析表明，来自单一机构的分离株显示完全相同的遗传类型，这表明只有单个受感染个体对阿米巴感染的扩大负有责任。进一步的研究表明，在一些感染率较高的机构中发现的基因类型与在神奈川县第一次爆发时发现的完全相同，并表明受感染的个人已从神奈川县的研究所转移到这些新的机构。该方法也适用于泰国等国外阿米巴分离株。然而，在这些外来分离株和国内菌株之间几乎没有发现巧合。非致病性阿米巴内阿米巴的无菌培养试验也在积极进行，最终产生了一种新设计的YIGADHA-S培养基，可以对这种阿米巴进行完全的无菌培养。通过研究阿米巴分离物的脱除过程和含硫氨基酸代谢过程，对其进行了生物学鉴定，并发现了几种新的抑制剂。将研究这些抑制剂作为药物开发先导化合物的可能性。采用叙利亚金仓鼠颊袋制备脓肿形成实验模型。少

Epidemiological and clinical studies were attempted for residents in institutions, who shoed high infection rates with Entamoeba histolytica. Biological analyses were also conducted on the ameba isolates from such individuals. The epidemiological analyses demonstrated as high as 30% positive rate by the specific antigen detection method and the conventional stool examination. However, most of the infected seemed to be due to the persistent asymptomatic infections with E.histolytica. Several strains of E.histolytica isolated from such individuals with the persistent infection showed genetic and antigenic properties consistent with those of E.histolytica ; however, they did show virtually no virulence against tissue-cultured cells as examined with a sensitive fluorescent method. Based on the base sequence polymorphism of 4 different genes like chitinase gene, identification of genetic types of subpopulations of E.histolytica was developed, and applied to the isolates from several institu … More tions. The analyses demonstrated that the isolates from a single institution showed entirely the same genetic type, suggesting that only single infected individual is responsible for expansion of the amebic infection.Further studies indicated that the gene type at a few institutions with rather high infection rates was exactly the same as that detected in the fist outbreak in Kanagawa Prefecture, and demonstrated that an infected individuals had moved from the institute in Kanagawa to these new institutions. This method was also applied to the ameba isolates from foreign countries lice Thailand. However, virtually no coincidence was detected between these foreign isolates and domestic strains. Trials of axenic cultivation of Entamoeba dispar, nonpathogenic ameba, was also actively conducted, which finally resulted in a newly designed YIGADHA-S medium, which allowed complete axenic cultivation of this ameba. Biological characterization of ameba isolates was also attempted by examining the process of excystation and sulfur containing amino acid metabolism, which resulted in discovery of several novel inhibitors. The possibility of these inhibitors as lead compounds for drug development will be investigated. The experimental model for abscess formation was produced by using a Syrian golden hamster cheek pouch. Less