Klebsiella pneumoniae capsular polysaccharide induces secretion of cytokines in bronchial epithelial cells via EGFR signaling pathway

AIM: To investigate the role of epidermal growth factor receptor (EGFR) in the secretion of inflammatory cytokines in human bronchial epithelial BEAS-2B cells induced by Klebsiella pneumoniae (KP) capsular polysaccharide (CPS). METHODS: KP was cultured in vitro, and the CPS was extracted. The BEAS-2B cells were stimulated with CPS at different concentrations, and the levels of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in the supernatant were measured by ELISA. The phosphorylation level of EGFR was detected by Western blot at different time points after stimulation. After pretreatment of the BEAS-2B cells with EGFR inhibitor AG1478, the phosphorylation level of ERK was detected by Western blot, the nuclear translocation of P65 was detected by indirect immunofluorescence, and the levels of TNF-α and IL-8 in the supernatant of the cells were measured. Finally, the levels of TNF-α and IL-8 in the culture supernatant of CPS-stimulated cells were detected by ELISA after pretreated with ERK inhibitor PD98059 and NF-κB inhibitor PDTC. RESULTS: Exposure to CPS at 10 mg/L for 12 h significantly induced the BEAS-2B cells to secret TNF-α and IL-8. The phosphorylation levels of EGFR and ERK and the nuclear translocation of p65 in the BEAS-2B cells were significantly increased after CPS stimulation (P<0.05). The phosphorylation level of ERK and the nuclear translocation of p65 were significantly reduced in the cells pretreated with EGFR inhibitor AG1478. Furthermore, the levels of TNF-α and IL-8 in the supernatant were significantly decreased after pretreated with the inhibitors of EGFR, ERK and NF-κB. CONCLUSION: Klebsiella pneumonia capsular polysaccharide activates the ERK and NF-κB signaling pathways via EGFR, and then induced the secretion of inflammatory cytokines TNF-α and IL-8 in the bronchial epithelial cells, indicating that EGFR may be a key factor in the inflammatory response induced by KP infection.     

Efficacy of antimicrobial therapy for bovine acute Klebsiella pneumoniae mastitis

The purpose of this retrospective study was to assess the efficacy of antimicrobial therapy for bovine acute Klebsiella pneumoniae mastitis. We evaluated data from cattle in Ehime, Japan, with naturally occurring acute mastitis due to K. pneumoniae (n=208) or Escherichia coli (n=201). Survival was significantly shorter in cattle with acute K. pneumoniae mastitis (median, 76 days) compared with the disease caused by E. coli (median 464 days). In 2004–2008, because both species were highly susceptible to cefazolin, cases of K. pneumoniae and E. coli mastitis were treated solely with cefazolin, yielding clinical cure rates of 52.8% for K. pneumoniae and 86.0% for E. coli. However, since 2009, the efficacy of treatment of K. pneumoniae mastitis with cefazolin alone has decreased. When cefazolin administered on the first disease day led to clinical improvement, treatment with cefazolin was continued. However, when cefazolin administered on the first disease day failed to yield clinical improvement, the antibiotic was switched to a fluoroquinolone on the second day, resulting in cure rates of 76.7% for K. pneumoniae and 80.0% for E. coli. These findings suggest that, when the first-line drug (e.g., cefazolin) is ineffective, promptly changing to a second-line drug (e.g., a fluoroquinolone) increases the cure rate for bovine K. pneumoniae mastitis.     

兔源支气管败血波氏杆菌和肺炎克雷伯菌的分离鉴定及其对抗菌药物的敏感性分析

兔感染支气管败血波氏杆菌（Bordetella bronchiseptica）和肺炎克雷伯菌（Klebsiella pneumoniae）后，常引起兔多发性呼吸道疾病，严重危害家兔养殖业。作者剖检河南省某兔场疑似病死兔，并采集组织分离鉴定病原菌，然后进行药敏试验，以期确定引起兔呼吸困难、腹泻的病原。结果显示，经细菌分离培养得到1株革兰阴性、两端钝圆的小杆状可疑致病菌及1株革兰阴性、卵圆形的可疑致病菌；其16S rRNA基因序列扩增片段大小分别为1 492和1 494 bp，与B. bronchiseptica AU 12671和K. pneumoniae菌株F5feb.57相似性分别为99.85%和100.00%，即该兔场患病兔为B. bronchiseptica和K. pneumoniae混合感染。药敏试验结果显示所分离的B. bronchiseptica和K. pneumoniae同时对庆大霉素、头孢曲松、头孢唑啉3种药物敏感，对其他药物有不同程度的耐药性。综上表明，此次分离的细菌为B. bronchiseptica和K. pneumoniae，本试验为家兔B. bronchiseptica和K. pneumoniae混合感染的分离鉴定及科学用药提供参考。     

我国植物支原体类病害的种类

 概述植物支原体类病的研究上阶段性重大成就,并将发现和发生的中国植物支原体类病整理成名录。     

金枪鱼豆腐加工工艺研究

[目的]优化金枪鱼豆腐的加工工艺配方,并探讨延长金枪鱼豆腐保质期的方法。[方法]选用黄鳍金枪鱼背部肌肉、大豆、淀粉、蛋清为原料,按照不同比例添加制作金枪鱼豆腐,同时以豆腐弹性、质构、微生物含量为指标,研究鱼豆腐品质和保鲜效果。[结果]试验表明,制作原料鱼浆用量、豆浆用量、淀粉用量、蛋清最佳比例为18.0 m L∶8.0 m L∶4.5 g∶1.6 g,此配方条件下加工制成的鱼豆腐质地较密,有弹性,煮后不开裂;极差分析显示,对鱼豆腐品质影响的因素从大到小依次为:鱼浆用量、豆浆用量、淀粉用量、蛋清;同时,添加乳酸链球菌素保鲜剂溶液,可使金枪鱼豆腐在室温下(20~25℃)保鲜3 d,冰箱(3~6℃)保鲜7 d。[结论]金枪鱼豆腐不仅提高了大豆生物价,而且含有人体必需的氨基酸,更接近人体平衡水平,具有其他鱼豆腐不可比拟的营养价值,口感好,做法简单方便,有较高的产品开发价值。     

水竹丛枝病的研究——Ⅰ.症状和病原

对水竹丛枝病的症状和病原进行观察研究表明:水竹丛枝病的典型症状是病枝节间缩短,侧枝、细枝丛生。每年从4月起,在病枝叶鞘内产生白色米粒状子座,5月中旬开始在其外围产生褐色垫状子座:即瘤座菌的有性世代;通过电镜观察,发现在病株同一组织的超薄切片中,同时存在类细菌,类菌原体和真菌菌丝,其中真菌菌丝的形态和大小与病株叶鞘内的瘤座菌子座切片菌丝相似。用分离培养的类细菌培养液针注接种能诱发致病,其症状与自然发病相同。进行再分离,其菌落形态、菌体大小和形态结构均与接种物相似。     

Detection of MLOs in declining alder trees in Southern Italy and their characterization by RFLP analysis

Mycoplasma-like organisms (MLOs) were detected and characterized by RFLP analysis in declining trees of Alnus glutinosa and A. cordata in Southern Italy for the first time. The infected trees showed symptoms of yellowing, sparse foliage, premature autumn colouration, sprouting, deliquescent branching, phloem necrosis, dieback and witches’ brooms.     

肺炎克雷伯氏菌致白颊长臂猿脓肿一例

白颊长臂猿是中、老、越三国交界地区的特有种,属于国家Ⅰ级重点保护动物。目前我国白颊长臂猿主要分布于西双版纳自然保护区和绿春黄连山自然保护区。北京动物园目前共饲养了十几只白颊长臂猿,繁殖状况良好。2009年9月我园1只白颊长臂猿体表出现多处脓肿。后抽取脓液,分离到1株革兰氏阴性小杆菌。该白颊长臂猿经治疗无效后死亡。剖检时发现其体内有亦有大量脓液,经分离培养,与体表分离到的是同一株细菌。该菌株经鉴定是肺炎克雷伯氏菌肺炎亚种（Klebsiella pneumoniae ssp pneumoniae）。并对其进行了药物敏感试验。     

Detection of Chlamydophila pneumoniae in cats with conjunctivitis

Objective To determine the presence of chlamydial species including recently described chlamydial agents as well as the human pathogen Chlamydophila pneumoniae in feline conjunctivitis. Animal studied Twenty five cats without and 49 cats with conjunctivitis were tested for chlamydia using a Chlamydiaceae real time (RT) PCR (targeting the 23S rRNA gene sequence), a Chlamydiales PCR (targeting the 16S rRNA gene sequence), and cell culture. The PCR products of all positive samples were sequenced and subsequently analyzed using a basic local alignment search tool search. Results Chlamydiaceae RT PCR and subsequent sequence analyses identified C. pneumoniae in five cats in the conjunctivitis group. The presence of Chlamydophila felis was shown in two cats with conjunctivitis. Chlamydiae related to uncultured members of Chlamydiales were detected in three conjunctivitis cases and in one cat without clinical symptoms. Conclusion This study detects for the first time, the known human pathogen C. pneumoniae in feline conjunctivitis cases using Chlamydiaceae RT PCR and sequence analyses.     

鸡毒霉形体粘附素

随着霉形体研究的迅速发展，国内外对鸡毒霉形体的研究也较为活跃， 特别在鸡毒霉形体的粘附素方面的研究、对鸡毒霉形体膜蛋白的粘附素MGC1、MGC2、GapA的生化特性、基因组分析、及其在免疫逃逸机制诊断探针方面的研究做了较为详细的综述。