Enterotoxigenic Escherichia coli는 신생 및 이유기 돼지 설사의 주요 원인체로서 전세계적으로 양돈산업에 큰 경제적 손실을 끼치고 있다. 그러나 현재 국내에는 이러한 E. coli가 보유하는 다양한 병원성유전자의 분포 및 특성에 대한 정보가 부족한 실정이다. 이에 본 연구에서는 2013년부터 2016년까지 국내 163개 양돈농장에서 이유기 설사증 개체로부터 면봉스왑 샘플을 채취하여 동일 농장의 개체일 경우 5개에서 10개 정도를 혼합한 후, MacConkey agar에 배양하여 최종 API 32E system을 통하여 동정하였다. 분리된 모든 균주에 대해서 3가지의 다른 multiplex PCR을 수행하여 총 13종의 병원성유전자의 분포를 확인하였다. 이를 통하여 총 172개의 최소 한가지 이상의 병원성 유전자를 가지는 E. coli 균주를 확인하였고, 그 결과 병원성 유전자의 분포는 (1) fimbrial adhesins (43.0%): F4 (16.9%), F5 (4.1%), F6 (1.7%), F18 (21.5%), and F41 (3.5%); (2) toxins (90.1%): LT (19.2%), STa (20.9%), STb (25.6%), Stx2e (15.1%), EAST1 (48.3%); and (3) nonfimbrial adhesin (19.6%): EAE (14.0%), AIDA-1 (11.6%) and PAA (8.7%)로 나타났다. 결론적으로 본 연구결과는 국내 양돈농장의 이유기 설사증에 관연하는 E. coli는 다양한 종류의 병원성 유전자를 가지고 있으며 그러한 병원성 유전자의 조합도 매우 다양하게 분포하고 있음을 나타낸다.

Enterotoxigenic Escherichia coli is one of the major causative infectious agents of diarrhea in newborn and post-weaning pigs and leads to a large economic loss worldwide. However, there is limited information on the distribution and characterization of virulence genes in E. coli isolated from diarrheic piglets, which also applies to the current status of pig farms in Korea. To investigate the prevalence and characterization of virulence genes in E. coli related to diarrhea in piglets, the rectal swab samples of diarrheic piglets (aged 2 d to 6 w) were collected from 163 farms between 2013 and 2016. Five to 10 individual swab samples from the same farm were pooled and cultured on MacConkey agar plates, and E. coli were identified using the API 32E system. Three sets of multiplex PCRs were used to detect 13 E. coli virulence genes. As a result, a total of 172 E. coli isolates encoding one or more of the virulence genes were identified. Among them, the prevalence of individual virulence gene was as follows, (1) fimbrial adhesins (43.0%): F4 (16.9%), F5 (4.1%), F6 (1.7%), F18 (21.5%), and F41 (3.5%); (2) toxins (90.1%): LT (19.2%), STa (20.9%), STb (25.6%), Stx2e (15.1%), EAST1 (48.3%); and (3) non-fimbrial adhesin (19.6%): EAE (14.0%), AIDA-1 (11.6%) and PAA (8.7%), respectively. Taken together, various pathotypes and virotypes of E. coli were identified in diarrheic piglets. These results suggest a broad array of virulence genes is associated with coliform diarrhea in piglets in Korea.

ABSTRACT
Materials and Methods
    Sample collection and E. coli isolation
    Polymerase chain reaction (PCR) to identify thevirulence factors
    Characterization and classification of E. coli isolates
Results
    Prevalence of individual virulence genes
    Identification of pathotypes and virotypes
    Distribution of toxin and non-fimbrial genes in thefimbrial isolates
Discussion
국문요약
Refrences

• Sung Jae Kim(Department of Veterinary Microbiology, College of Veterinary Medicine, Seoul National University)
• Woo Kyung Jung(Department of Veterinary Microbiology, College of Veterinary Medicine, Seoul National University)
• Joonbae Hong(Food & Microbiology Team, Test & Research Department, Consumer Safety Center, Korea consumer Agency)
• Soo-Jin Yang(Department of Animal Science and Technology, Chung-Ang University)
• Yong Ho Park(Department of Veterinary Microbiology, College of Veterinary Medicine, Seoul National University)
• Kun Taek Park(Department of Biotechnology, Inje University) Correspondence to