배양시간(6, 12, 24, 48시간)에 따른 Yersinia enterocolitica 균체 및 배지 대사체들의 변화를 이해하기 위하여 GC/MS와 다변량통계분석을 이용하여 분석한 결과 Partial Least Squares-Discriminant Analysis(PLS-DA) scores plots 상에서 배양시간에 따라 분석 시료들이 뚜렷하게 분리되었다. 시료들 사이의 차이에 관여하는 대사물질들을 동정한 결과 균체에서는 ethylene glycol, valine, ethanolamine, succinic acid, adenine, stearic acid, 배지에서는 glycine, fumaric acid, threonine, aminomalonic acid, malic acid, glutamic acid, citric acid가 배양시간에 따른 차이가 나는 것으로 확인되었다. 이들 대사물질들을 이용하여 관련 대사경로를 도출한 결과 배양시기에 따라 에너지 생성에 관여하는 대사경로가 주로 변하는 것으로 관찰되었다. Y. enterocolitica의 경우 대수기 초기에는 TCA cycle을 통해 에너지를 공급하다가 정지기에 들어서면서 정상적인 TCA cycle를 수행하지 못하고 ethanolamine 및 ethylene glycol 등 다른 탄소원 또는 질소원을 공급하는 것으로 확인되었다. 비록 관련된 많은 연구가 필요함에도 불구하고 대사체분석 기술을 활용한 Y. enterocolitica 균체 및 배지 분석 연구는 배양시간에 따른 대사과정의 변화를 관찰할 수 있을 뿐만 아니라 향후 균체 연구의 다양한 분야에 접목될 수 있을 것으로 사료된다.

Five different enrichment methods were studied to find an optimal method to recover Yersinia enterocolitica from swine feed samples. When the recovery of Y. enterocolitica GER-C (serotype O:3) strain was studied at 1000 CFU/g feed, phosphate-buffered saline (PBS) enrichment at 4℃ and PBS plus sorbitol and bile salts (PSB)enrichment at 4℃ and 21℃ were not effective (< 22%). In contrast, both irgasan-ticarcillin-potassium chlorate (ITC)and tryptic soy broth plus polymyxin B sulfate and novobiocin (TSBPN) enrichment methods showed a full recovery (100%) at 100-1000 CFU/g feed. At 10 CFU/g feed, both ITC and TSBPN methods still recovered the strain (> 50%). In recovery of ATCC 9610 (serotype O:8) strain, TSBPN method was more sensitive than any other methods (P < 0.05) at 1000 CFU/g feed. Using TSBPN method, the strain was still recovered at 100 CFU/g feed, but not at 10CFU/g feed. With its sensitivity and relatively simple recipe, TSBPN was most desirable method to recover Y. enterocolitica from swine feed samples.

It was performed to investigate for Yersinia species from 2,841 spring waters in Seoul, from 1994 to 1998. Of them, Yersinia spp. were isolated 86 isolates (3.3%). Of 86, sixty two isolates (72.1%) were Yersinia enterocolitica, followed by Y. aldouae (11 strains), Y. pseudotuberculosis (5 strains), Y. frederiksenii (3 strains), unclassified Yersinia spp. (5 strains). Yersinia spp. were highest isolated from Nowon-Gu (22 samples) and Bukhan Mountain Park isolates (18 samples). We tested 1.186 samples for SPC and coliform from 1996 to 1998. Of these tests, the positive rate of coliform was 23.6%, SPC, 9.1%, and either coliform or SPC positive 27.1%. The positive rates of coliform and SPC were decreased 26.7%, 12.7% in 1996, 25.8%, 6.3% in 1997 and 18.1%, 7.6% in 1998, respectively. Of Y. enterocolitica, 78% was resistant to ampicillin and carbenicillin. In the case of Y. aldouae, only 3 of 11 isolated were resistent to carbenicillin. Y. pseudotuberculosis were resistant to colistin. Also Y. frederiksenii to carbenicillin. There were many spring waters of Y. enterocolitica isolated from Nowon-Gu and Buk-han Mountain Park. So, it needs to clean the environment of those regions.