The present invention relates to a novel bacteriophage KP1 having killing activity specific to a bacterium belonging to the genus Klebsiella, particularly an extended-spectrum beta-lactamase ( Klebsiella ) bacterium, a Klebsiella bacterium comprising the bacteriophage A method for preventing or treating an infectious disease caused by Klebsiella, which comprises the step of administering to a subject a pharmaceutical composition, antibiotic composition, feed additive composition, feed, disinfectant or detergent for preventing or treating infectious diseases caused by infectious diseases . The method for preventing or treating infectious diseases caused by Klebsiella spp. Using the bacteriophage KP1 of the present invention is more specific than the conventional antibiotics such as Klebsiella spp., Especially ESBL-Klebsiella spp. And the bacteriophage KP1 has an advantage of being excellent in physicochemical stimulation by exhibiting excellent lytic activity by infection with Klebsiella spp. In addition, since the bacteriophage KP1 of the present invention is not infected with any host other than a bacterium such as a human, an animal, or a plant, it has an advantage of being able to solve problems of antibiotic resistant bacteria caused by abuse of antibiotics, have. Accordingly, the bacteriophage KP1 of the present invention can be used in various fields in the field of preventing or treating infectious diseases caused by Klebsiella spp., Antibiotic composition, composition for feed addition, feed, disinfectant, or detergent.본 발명은 클렙시엘라(Klebsiella) 속 세균, 특히 ESBL(extended-spectrum beta-lactamase)-클렙시엘라 속 세균에 특이적인 사멸능을 갖는 신규 박테리오파지 KP1, 상기 박테리오파지를 포함하는 클렙시엘라 속 세균에 의한 감염성 질병의 예방 또는 치료용 약학적 조성물, 항생용 조성물, 사료 첨가용 조성물, 사료, 소독제 또는 세척제 및 상기 박테리오파지를 개체에 투여하는 단계를 포함하는 클렙시엘라에 의한 감염성 질병의 예방 또는 치료 방법에 관한 것이다. 본 발명의 박테리오파지 KP1을 이용한 클렙시엘라 속 세균에 의한 감염성 질병의 예방 또는 치료 방법은 기존의 항생제 등의 화학물질에 비해 클렙시엘라 속 세균, 특히 ESBL-클렙시엘라 속 세균에 대한 특이성이 매우 높고, 상기 박테리오파지 KP1은 클렙시엘라 속 세균에 감염하여 탁월한 용균 활성을 나타내
