Earthworms, especially Eisenia andrei, are cultivated for a variety of purposes including waste disposal and compost production. In this study, bacteria from earthworm gut were cultured and the dominant species identified. Subsequently, we isolated bacteriophages able to lyse the isolated gut bacteria. Two dominant genera of gut bacteria, Aeromonas sp. and Citrobacter sp. were identified by using MALDI-TOF MS analysis and a library was constructed to find lytic phages. Phage EF1 showed lytic activity for C. freundii and two Citrobacter isolates, C. braakii and C. murliniae. These 3 species have similar sensitivities to EF1. Several aspects of the life cycle of EF1 were investigated by using C. freundii under optimal growth conditions. EF1 infects C. freundii with a moderate latent period, approximately 25 min, and a large burst size averaging 5 × 109 per infected cell. Moreover, the antimicrobial activity of EF1 was well maintained under diverse conditions including a broad temperature range of 40°C to 50°C and a wide pH range of 4 to 11. In conclusion, the results indicate that earthworm casting contain a wide range of bacteria species, for which there are various corresponding bacteriophages.

Abstract
 서 론
 재료 및 방법
  지렁이 샘플
  세균 분리 및 동정
  박테리오파지 분리 및 역가 측정
  박테리오파지의 적정 배양온도에 따른 역가 측정, 성장곡선 작성 및 Citrobacter sp.에 따른 감수성 테스트
  박테리오파지의 균 배양 시간에 따른 역가 측정 및Citrobacter sp.에 따른 감수성 테스트
  박테리오파지의 CaCl2 및 MgSO4 따른 역가 측정
  박테리오파지의 온도 및 pH에 따른 안전성 실험
  전자현미경 관찰
 결 과
  세균 분리 및 동정
  박테리오파지 분리 및 역가 측정
  박테리오파지(EF1)의 적정 배양온도에 따른 역가 측정,성장곡선 작성 및 Citrobacter sp.에 따른 감수성 테스트
  박테리오파지의 CaCl2 및 MgSO4 첨가와 온도 및 pH에 따른 안전성 실험
  전자현미경 관찰
 고 찰
 REFERENCES

• Geun Jung(Geochang Daeseong Highschool)
• Jung Seok Lee(Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University)
• Hong Jae Shin(Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University)
• Jung Yeol Bae(Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University)
• Ae Rin Lee(Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University)
• Sam woong Kim(Swine Science and Technology Center, Gyeongnam National University of Science & Technology)
• Byung Jin Lee(Swine Science and Technology Center, Gyeongnam National University of Science & Technology)
• Chi Won Noh(Gyeongsangnam-do Agricultural Research and Extension Services)
• Tae Sung Jung(Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University) Corresponding Author