亚洲象粪便中产酸克雷伯菌分离鉴定及致病性研究

Isolation,Identification and Pathogenicity of Klebsiella oxytoca in Asian Elephant Stool

昆明市某公园,1头亚洲象出现排便次数减少、粪便带有鲜血、四肢发抖、体温升高、触腹部坚实等症状。为找准大象病因,本实验采集该大象粪便,在云南省动物疫病预防控制中心进行试验,通过细菌分离培养、革兰氏染色镜检、选择鉴别培养基进行鉴别培养、生化试验和PCR扩增及产物测序等方法对其粪便细菌进行分离鉴定,实验结果表明:粪便中有大肠杆菌O83∶H1、大肠杆菌O104∶H4和产酸克雷伯菌(Klebsiella oxytoca)等多种条件致病菌;并对其不太常见的产酸克雷伯菌进行药敏试验,该细菌对氧氟沙星、头孢曲松、头孢赛肟钠、环丙沙星、卡那霉素、磺胺异亚唑等极度敏感;对阿莫西林、多粘菌素B等高度敏感;对万古霉素等中度敏感;对甲氧嘧啶耐药。产酸克雷伯菌的动物回归试验研究结果表明:接种过菌液的小鼠表现出腹泻和食欲下降等临床症状,严重的发生死亡,解剖症状主要是肝脏部分坏死、肠道充血肿胀、肺脏有出血点,证明其对小鼠易感且具有较强的致病性,产酸克雷伯菌最小致死量(MLD)为2.5×10^(12)cfu/mL;半数致死量为5×10^(13)cfu/mL。本次研究旨在加强对产酸克雷伯菌生理生化特性及致病性的了解,为临床诊断提供可靠的依据和有效的治疗方法。

In a park in Kunming city,Yunnan Province,an Asian elephant showed symptoms including reduced bowel movements,stool with blood,trembling limbs,increased body temperature,and solid abdomen.To understand the causes of the disease,the faeces of the elephant was sampled and subjected to the Animal Disease Prevention and Control Center of Yunnan Province for testing.The stool bacteria were isolated and identified by bacterial separation and culture,gram staining microscopy,selective identification medium selection and culture,biochemical tests and PCR amplification and sequencing.Escherichia coli O83:H1,Escherichia coli O104:H4,Klebsiella oxytoca and other opportunistic pathogens were found in the stool,and the pathogenic susceptibility of the less common K.oxytoca was tested.This bacterium is extremely sensitive to ofloxacin,ceftriaxone,cefotaxime sodium,ciprofloxacin,kanamycin,sulfadiazole,and other drugs.It is highly sensitive to amoxicillin and polymyxin B,moderately sensitive to vancomycin,and resistant to methicillin.Animal regression analysis of K.oxytoca showed that inoculated mice showed signs of diarrhea and loss of appetite and other clinical symptoms,and even death.The anatomical symptoms were mainly partial necrosis of the liver,intestinal congestion and swelling,and hemorrhaging at points in the lungs.This indicated that mice are susceptible to K.oxytoca,which has strong pathogenicity.The minimum lethal dose of K.oxytoca was 2.5×10 12 cfu/mL and median lethal dose was 5×10 13 cfu/mL.This study aimed to enhance understanding of K.oxytoca and provide a reliable basis and an effective treatment for clinical diagnosis.