AP631炭疽噬菌体裂解蜡样芽胞杆菌的发现和鉴定

目的 AP631炭疽噬菌体裂解蜡样芽胞杆菌的发现和鉴定。方法通过革兰氏染色、菌落形态特征、噬菌体裂解试验、青霉素敏感试验、溶血试验、生化试验和蛋白质毒素结晶试验对炭疽疫点现场分离的5株菌进行蜡样芽胞杆菌的鉴定,通过PCR扩增、小白鼠毒力测定试验和MLST基因检测等方法对该5株菌和本实验室保存的3株被AP631炭疽噬菌体裂解的蜡样芽胞杆菌进行毒力和基因测定。结果确定了8株可被AP631炭疽噬菌体不完全裂解的蜡样芽胞杆菌。从疫点采集分离的5株菌青霉素敏感试验阴性,炭疽毒力基因PCR扩增阴性,排除了炭疽芽胞杆菌;蛋白质毒素结晶试验染色试验为阴性,排除了苏云金芽胞杆菌;根据溶血试验和生化反应等一系列鉴别实验鉴定为蜡样芽胞杆菌。8株菌的MLST基因检测发现5株菌有新的等位基因位点或ST型。结论本研究首次证明我国使用的炭疽芽胞杆菌诊断AP631噬菌体可以不完全裂解部分蜡样芽胞杆菌,存在非特异性裂解现象,提示在今后使用噬菌体鉴定炭疽杆菌时,对于外环境分离到的可疑芽胞杆菌,特别要注意关于噬菌体不完全裂解的问题,这将为炭疽诊断标准的正确制订提供新的认识并具有重要的指导意义。     

从血液及尿道分泌物分离出蜡样芽胞杆菌

蜡样芽胞杆菌广泛分布于土壤及空气中，常规下不致病，在特定条件下可引起食物中毒，由芽胞杆菌所致的其他疾病比较少见，１９９９年６月２８日，我科从一患者的血及尿道分泌物中均分离出本菌，现报告如下。　　病例简介　患者、刘某、男性、２８岁，住院号１０６３９８，因发烧，小便疼痛有分泌物，来院就诊，并收住内科。查体Ｔ３９℃ＷＢＣ２２×１０９／Ｌ分类Ｎ０．９３，Ｌ０．７ＨＢ１４６ｇ／Ｌ，尿液检查：脓球４＋，尿糖阴性，临床诊断：泌尿系感染，入院当天取血及尿道分泌物作细菌培养，均检出蜡样芽胞杆菌，经用敏感药物，丁胺…     

洋快餐引起的蜡样芽孢杆菌食物中毒

本文报道一起由蜡样芽孢杆菌污染食物引起2人食物中毒的事件。根据流行病学调查,临床症状,实验室检验结果,确认该起食物中毒是由外带洋快餐受蜡样芽胞杆菌污染所致。     

楚雄市1起蜡样芽胞杆菌食物中毒调查报告

目的通过流行病学调查和实验室检测探讨1起食物中毒的流行因素及病原学。方法按照流行病学现场调查方法和实验室细菌学鉴定方法。结果共有18人进餐,10人出现食物中毒症状,罹患率为55.56%,采集到剩余米饭、腌卤腐及腌豆豉样品各1份,中毒者呕吐物2份,患者呕吐物及米饭中均检出蜡样芽胞杆菌。结论该起食物中毒为蜡样芽胞杆菌污染食品所致。     

蜡样芽胞杆菌引起食物中毒19例

蜡样芽胞杆菌引起食物中毒１９例于兆婉，韩伟，陶金祥我院于１９９３年３月２８日收治了一批以头晕，恶心呕吐为主要症状，伴有发热，经临床诊断食物中毒的病人。现报告如下。１，一般概况某部队位于沈阳市中心，于１９９３年３月２８日１５时３０分开饭，同时就餐４４人...     

眼源性蜡样芽孢杆菌vrrA基因型及其与病情和预后关系

目的建立PCR检测眼源性蜡样芽孢杆菌,了解不同vrrA基因型蜡样芽孢杆菌感染与临床病情和预后关系。方法选择vrrA为靶基因设计引物,建立检测蜡样芽胞杆菌PCR。PCR产物用琼脂糖凝胶电泳检测并进行序列测定。采用Clustal 软件对获得的vrrA基因序列进行分型。对不同vrrA基因型蜡样芽胞杆菌感染与眼内炎患者病情严重程度及转归分析与比较。结果所建立的PCR可有效检测眼源性蜡样芽胞杆菌并有较高的敏感性和特异性。5株分离自眼内炎患者标本中的蜡样芽胞杆菌可分为MT1、MT2、MT3三种vrrA基因型,其中MT1、MT2型各2株,MT3型1株。MT1和MT2型蜡样芽胞杆菌感染性眼内炎病情重、预后差,MT3型蜡样芽胞杆菌感染性眼内炎病情较轻、预后较好。结论vrrA基因为靶基因的PCR可用于眼源性蜡样芽孢杆菌快速检测。不同蜡样芽孢杆菌vrrA基因型感染所致的眼内炎病情严重程度及转归有明显差异。     

2011-2018年天水市食品中蜡样芽胞杆菌监测分析

目的了解甘肃省天水市食品中蜡样芽胞杆菌污染情况,为防治由该菌引起的食源性疾病提供科学依据。方法2011—2018年从天水市餐饮服务环节和流通环节随机采集7类共计586份食品样本,按《国家食品污染和有害因素风险监测工作手册》中方法,分离鉴定蜡样芽胞杆菌。结果 586份样品中,检出蜡样芽胞杆菌115份,总检出率为19.62%,其中2015年检出率最高(40.00%);食品以天水浆水检出率最高(40.00%),差异有统计学意义(χ2=21.92,P0.05);蜡样芽胞杆菌定量检测,菌落数小于100 cfu/g(ml)的占53.91%,100～1 000 cfu/g(ml)的占33.91%,1 000 cfu/g(ml)以上的占12.18%。结论甘肃省天水市食品中蜡样芽胞杆菌污染较严重;相关部门应加大食品卫生监管力度、加强从业人员培训、扩大健康教育宣传,确保食品安全。     

从血液及尿道分泌物分离出蜡样芽胸杆菌

蜡样芽胞杆菌广泛分布于土壤及空气中,常规下不致病,在特定条件下可引起食物中毒,由芽胞杆菌所致的其他疾病比较少见,1999年6月28日,我科从一患者的血及尿道分泌物中均分离出本菌,现报告如下。病例简介:患者刘某,男性,28岁,住院号106398,因发烧,小便疼痛有分泌物,来院就诊,并收住内科。查体T39℃,WBC22×109/L,分类No.93,L0.7HB146g/L,尿液检查:脓球4 ,尿糖阴性,临床诊断:泌尿系感染,入院当天取血及尿道分泌物作细菌培养,均检出蜡样芽胞杆菌,经用敏感药物,丁胺卡那霉素等,治疗后,病情好转,痊愈出院。1　细菌学鉴定1.1　形态与染色　为革…     

蜡样芽胞杆菌引起食物中毒两起调查报告

1975年7月和1978年6月,我市发生两起由蜡样芽胞杆菌引起的食物中毒。第一起发生在某轮船上,食用“霉菌”大米饭(大米饭煮熟后等温度降到30℃左右,放入发酵粉,经1～2天发酵后食用)。食后1～2     

市售婴幼儿食品蜡样芽胞杆菌污染状况调查

目的 了解甘肃省市售婴幼儿食品蜡样芽胞杆菌污染状况.方法 2018-2020年随机抽取甘肃省14个地(州、市)的百货商场、便利店/零售店、超市和网店等场所在售婴幼儿食品640份,应用平板计数法检测蜡样芽胞杆菌,以荧光PCR方法检测呕吐型基因.结果 640份样本中,蜡样芽胞杆菌总阳性率为15.00％(96/640),其中婴儿配方食品17.98％(41/228)、较大婴儿和幼儿配方食品18.64％(22/118)、婴幼儿谷类辅助食品11.22％(33/294);网店阳性率最高26.04％(25/96),呕吐型蜡样芽胞杆菌阳性率为6.25％(6/96);定量结果大于100 cfu/g的阳性样本占16.67％(16/96).结论 甘肃省市售婴幼儿食品存在蜡样芽胞杆菌污染,有潜在食品安全隐患,建议相关监管部门严格监督检查.     

Studies on the enteropathogenic mechanism of non-O1 Vibrio cholerae. IV. Role of hemolysin

The role of hemolysin in the enteropathogenic mechanism of non-O1 V. cholerae was experimentally investigated, in vitro and in vivo. Results are summarized as follows. 1). A greater majority of enteropathogenic strains produced hemolysin in Eagle MEM medium supplemented with 10% calf serum and in the rabbit ileal loop, while most non-enteropathogenic strains did not under the same conditions. 2). Non-enteropathogenic mutants derived from enteropathogenic parent strains produced much less hemolysin than that of parent strains. 3). A significant inhibition of the fluid accumulation in the ligated rabbit ileal loop test with viable cells was noted in rabbit immunized with purified hemolysin. These results indicate that hemolysin is the most important toxin in the enteropathogenic mechanism of non-O1 V. cholerae.     

A hospital food-borne outbreak of diarrhea caused by Bacillus cereus: clinical, epidemiologic, and microbiologic studies.

An outbreak of diarrhea involving 28 patients occurred in two wards of a chronic disease hospital. The illness was characterized by abdominal cramps and watery diarrhea without vomiting or fever. An epidemiologic investigation suggested food-borne intoxication and incriminated turkey loaf served at the preceding evening meal as the source of the outbreak. Bacillus cereus was isolated both from the stool of all 14 symptomatic patients who were cultured and from turkey loaf. No other enteropathogens were found. The isolate of B. cereus was shown to elaborate an enterotoxin that caused fluid secretion in assays in the rabbit ileal loop and suckling mice and that also caused a positive response in the Y-1 adrenal cell assay. B. cereus is an enteropathogen that should be sought in outbreaks of food-related gastroenteritis. This organism affects the gastrointestinal tract probably by the elaboration of enterotoxins.     

Enteropathogenicity and enteropathogenic toxin production of Vibrio mimicus]

Enteropathogenicity and enteroreactive-toxins were examined in 66 strains of Vibrio mimicus and the following results were obtained. Frequencies of enteropathogenic strains judged by the result of suckling mouse tests were 11/13 (85%) for clinical isolates and 37/53 (70%) for fish or environmental isolates. Frequencies of preservation of cholera toxin gene and NAG-ST gene were 2 and 15%, respectively, for 48 enteropathogenic strains, and 0 and 6%, respectively, for 18 non-enteropathogenic strains. Frequencies of production of NAG-rTDH, FAF and hemolysin were 4, 63 and 100%, respectively, for 48 enteropathogenic strains, and 6, 50, and 100%, respectively, for 18 non-enteropathogenic strains. No correlation between serovar and enteropathogenicity was observed in the suckling mouse test. Six out of 12 enteropathogenic strains produced hemolysin in ligated rabbit ileal loop, while 1 out of 12 non-enteropathogenic strains did so under the same condition. A significant inhibition of fluid accumulation in the ligated rabbit ileal loop test with viable cells was noted in rabbits immunized with hemolysin of non-O1 V. cholerae. These results suggest that approximately two-thirds of environmental isolates are enteropathogenic and that hemolysin is the most important toxin in the enteropathogenic mechanism of V. mimicus strains.     

肠球菌溶血素与其致病力的关系

目的　探讨肠球菌溶血素的毒力因子作用。方法　分别检测 3 9株临床标本分离的粪肠球菌以及 3 1株健康人群粪便分离的粪肠球菌的溶血素检出率 ;并检测了β溶血肠球菌、非 β溶血肠球菌对 9种抗生素的敏感性。 结果　临床菌株的溶血素检出率为 5 8.9% ,健康人群分离株的溶血素检出率为 19.3 % (P <0 .0 0 5 ) ;β溶血株对抗生素的耐药性明显高于非 β溶血株 (P <0 .0 1)。结论　以上结果提示肠球菌溶血素与其毒力有关     

Bacillus cereus infections in Traumatology-Orthopaedics Department: retrospective investigation and improvement of healthcare practices

OBJECTIVE: To investigate 41 open fractures infected with Bacillus cereus in a Traumatology-Orthopaedy ward and propose a care protocol at admission. METHODS: All B. cereus strains isolated from patients hospitalized in the Traumatology-Orthopaedy ward between March 1997 and August 2001 were submitted to molecular analysis (RAPD and PFGE) in order to investigate a putative outbreak. Susceptibility to the main antibiotics and antiseptics used in this kind of surgery was also evaluated. RESULTS: The B. cereus clinical isolates were mainly isolated from patients who had initially open fractures and were not clonally related. Furthermore, analysis of the clinical data was in favour of a telluric contamination of the wound (wound contamination with terrestrial environments) before admission. Finally, betalactam antibiotics used for prophylactic chemotherapy were not effective against the strains tested as well as the antiseptics who displayed poor effect. CONCLUSION: B. cereus could be termed an emerging pathogen and people need to be aware of its potential importance in orthopaedic trauma cases. In this purpose, a systematic screening for B. cereus at admission should be necessary in front of patients with open fractures associated with telluric contamination. Furthermore, if this bacterium can be isolated, chemotherapy should be based upon ciprofloxacin that would prevent the development of B. cereus infection responsible for deleterious complications.     

Studies on the enteropathogenic mechanism of non-O1 Vibrio cholerae. III. Production of enteroreactive toxins

Cholera toxin gene and production of enteroreactive toxins were examined in 134 strains of non-O1 V. cholerae. Results obtained were summarized as follows. Frequencies of cholera-toxin-gene-positive strains were 2/58 (3.4%) from human sources and 2/76 (2.6%) from fish and environment. While, frequencies of production of hemolysin, fluid accumulating factor (FAF) related with protease, fluid accumulating factor in the suckling mouse, NAG-rTDH, NAG-ST and Vero toxin were 100, 72, 31, 2, 0 and 0%, respectively, for 58 strains from human sources, and 100, 57, 24, 0, 1.3 and 0%, respectively, for 76 strains from fish and environment. Among the 31 strains used for the injection of viable cells to the ligated rabbit ileal loop, detection frequencies of these enteroreactive toxins in the accumulated fluids were 100% for hemolysin, 3.2% for both FAF and NAG-rTDH and 0% for cholera toxin, Vero toxin or NAG-ST. Hemolysin and the fluid accumulating factor in the suckling mouse seemed to be identical in most strains. These results suggest that cholera toxin, NAG-ST, NAG-rTDH and Vero toxin may not be very important in the enteropathogenic mechanism of a great majority of non-O1 V. cholerae strains, whereas hemolysin may play an important role in the enteropathogenicity.     

Fulminant septicaemic syndrome of Bacillus cereus: three case reports

Three patients with acute leukaemia, who were severely neutropenic and iatrogenically immunosuppressed post-chemotherapy, developed rapidly fatal septicaemic shock and coma caused by Bacillus cereus (B. cereus). The illness was marked by two phases: a mild febrile illness lasting 6-14 h and accompanied by subtle symptoms of autonomic sympathetic nervous system overactivity, and a second short fulminant one, marked by high fever of 40-41 degrees C accompanied by major central nervous system disturbances, and ending with deep coma and brain stem dysfunction. One patient developed the sepsis in spite of 4 days of coverage with amikacin. In the other two patients, amikacin was commenced at the earliest phase of the infection, but failed to influence the outcome. This form of B. cereus sepsis in neutropenic patients seems to be caused by strains capable of causing bacteraemia and meningitis and has the ability to produce a substance that causes leptomeningeal and neuronal necrosis. Lack of early clinical and laboratory markers inevitably leads to death. Use of antibiotics effective against B. cereus and capable of achieving high concentrations in the cerebrospinal fluid. and identification and neutralization of the necrotizing substance may hopefully help to reverse this fatal illness.     

The incidence of Bacillus cereus in foods in Central Thailand

Thirty of 53 different raw and cooked or processed foods obtained in Central Thailand were demonstrated to contain Bacillus cereus. The level of contamination was found to depend on the type of food sampled; the mean was 3.2 X 10(6) organisms/gm on raw and cooked or processed foods ready for consumption, and 2.8 X 10(8) organisms/gm on cooked or processed foods kept overnight at kitchen temperature. B. cereus was commonly found on rice (both uncooked and boiled or fried), dried chilli pepper, shrimp paste, and on certain kinds of cooked foods seasoned with these products. Most of the total of 275 B. cereus isolates were found to possess biochemical reactions typical for B. cereus. Variations were also examined among several isolates. Nineteen per cent of the isolates did not produce acid from salicin. Certain types of the food tested were also demonstrated by volunteer experiments to carry enterotoxigenic B. cereus.     

Listeria monocytogenes phosphatidylinositol-specific phospholipase C has evolved for virulence by greatly reduced activity on GPI anchors

Listeria monocytogenes phosphatidylinositol-specific phospholipase C (PI-PLC) plays a critical role in escape of this human pathogen from host cell vacuoles. Unlike classical bacterial PI-PLCs, the L. monocytogenes enzyme has very weak activity on glycosylphosphatidylinositol (GPI)-anchored proteins. Previous crystal structure analysis has revealed that a small beta-strand (Vb) is present in Bacillus cereus PI-PLC and is absent in the enzyme from L. monocytogenes. This Vb beta-strand in B. cereus PI-PLC forms contacts with the glycan linker of GPI anchors, which presumably increases its activity on GPI-anchored proteins. In this study, we show that, of all known bacterial PI-PLCs, those from listeriae are the only ones that lack the beta-strand. Expression by L. monocytogenes of B. cereus PI-PLC, which has strong activity on GPI-anchored proteins, inhibited bacterial escape from a vacuole and cell-to-cell spread, resulting in greatly reduced virulence in mice. Deletion of the Vb beta-strand from B. cereus PI-PLC abolished its ability to cleave GPI-anchored proteins, decreased its inhibitory effects, and increased its virulence in mice. These results strongly suggest that L. monocytogenes PI-PLC has evolved as an important determinant of L. monocytogenes pathogenesis by absence of the Vb beta-strand, thus leading to greatly reduced activity on GPI-anchored proteins.     

Bacillus cereus fatal bacteremia and apparent association with nosocomial transmission in an intensive care unit

Bacillus cereus has sometimes been implicated in food poisoning and in opportunistic infections of seriously ill patients. This report describes an unusual case of persistent bacteremia and multiple organ failure associated with B. cereus in a patient admitted to our institution for lung cancer. The patient was undergoing treatment with an antimicrobial agent (imipenem) that was shown to be effective against the micro-organism in vitro. No portal of entry for the strain was detected. After treatment with vancomycin, also shown to be effective in vitro, no clinical improvement was noted and the patient died. Molecular studies showed that the same strain caused an episode of pseudobacteremia in another patient admitted to the same ICU room.