PPT課件腸道桿菌PPT課件PPT課件

1、腸桿菌科目前有44個(gè)菌屬、170多個(gè)種。多為腸道正常菌群，但可成為條件致病菌；少數(shù)為致病菌。第1頁/共31頁A. All bacilli belonging to Enterobacteriaceae are short gram-negative rods, either mobile or non-mobile. 第2頁/共31頁B. All bacilli belonging to Enterobacteriaceae are facultative anaerobes. They grow in common media. Most of the enteric bacilli for

2、m round, convex, smooth colonies with distinct edges.第3頁/共31頁Mechanism: Non-pathogenic enteric bacilli can ferment lactose while pathogenic enteric bacilli such as Shigella and Salmonella can not.Media: SS-plate or EMB plate , TSI agar slantsBasic components: lactose and a pH indicatorC. The identif

3、ication of Enterobacteriaceae is largely depend on biochemical reactions第4頁/共31頁SS plate第5頁/共31頁D. Enterobacteriaceae have complex antigenic structures.H Ag (flagella) somatic O Ag (lipopolysaccharide)K/Vi Ag (capsule) 第6頁/共31頁第7頁/共31頁Infections outside the intestines caused by bacterial translocati

4、on Opportunistic infection including septicemia, pneumonia, meningitis and urinary tract infections Community-acquired infectionurinary tract infections第8頁/共31頁E. coli associated urinary tract infectionE. coli causes urinary tract infections such as acute cystitis（ 急 性 膀 胱 炎 ） a n d pyelonephritis（腎

5、盂腎炎）.第9頁/共31頁Infections inside the intestines caused by pathogenic E. coliCommon symptoms include Gastroenteritis（腸胃炎）, diarrhea（腹瀉） and dysentery（痢疾）. Disease transmission is by fecal-oral route （糞口途徑）.第10頁/共31頁Cause travellers diarrhea. Two types of plasmid-encoded toxins are produced: Heat labile

6、 toxins (LT/耐熱腸毒素耐熱腸毒素)activate adenyl cyclase（腺苷環(huán)化酶）（腺苷環(huán)化酶） which catalyze ATP to cAMP Heat stable toxins (ST/不耐熱腸毒素不耐熱腸毒素)activate guanyl cyclase（鳥苷環(huán)化酶）（鳥苷環(huán)化酶） to catalyze GTP to cGMP cAMP/cGMP are the intracellular second messagers. The former increases the secretion of water and ions, and the la

7、tter inhibits ionic uptake. Clinical signs: watery diarrhea, fever and nausea.第11頁/共31頁 Commonly associated with infant diarrhea. Characteristic lesion with destruction of microvilli without invasion Clinical signs: fever, diarrhea with non-bloody stools, vomiting and nausea.第12頁/共31頁第13頁/共31頁 Assoc

8、iated with elder children and adult diarrhea. Without flagella High virulence: a small number of EIEC can cause serious illness Clinical signs: Acute inflammatory responses and tissue destruction. Produce diarrhea with little fluid, much blood and mucus containing polymorphonuclear cells. 第14頁/共31頁E

9、HEC produces bacteriophage-mediated exotoxin. This toxin is called Vero toxin (VT) because of its cytotoxicity to cultured Vero cells. The illness is characterized by serious abdominal pain and diarrhea which is initially watery but then becomes bloody. In children, the disease may be progressed to

10、a systemic stage called as hemolytic uremic syndrome (kidney injury) with 10% death rate.第15頁/共31頁 A dominant serotype of EHEC is E. coli O157:H7 第16頁/共31頁 It causes a persistent, mucus-watery diarrhea with vomiting and dehydration in infants. It produces enteroaggregative heat-stable toxin (EAST) s

11、imilar to the heat stable toxins of ETEC. It produces mucous associated autoagglutinin which causes aggregation of the bacteria and formation of biofilm. 第17頁/共31頁E. coli Enterobacter AerogenesIMViC testIndole testMethyl red (MR) testVoges-Proskauer (VP) testCitrate utilization test枸櫞酸鹽試驗(yàn)吲哚試驗(yàn)甲基紅試驗(yàn)產(chǎn)氣

12、腸桿菌菌毛疫苗菌毛疫苗第18頁/共31頁QUIZ 1主要引起嬰兒和旅行者腹瀉的大腸埃希菌是：A.腸產(chǎn)毒型大腸埃希菌B.腸致病型大腸埃希菌C.腸侵襲型大腸埃希菌D.腸出血型大腸埃希菌第19頁/共31頁痢疾發(fā)病總數(shù)在前五位，死亡在前十位（傳染?。└锾m氏陰性短小桿菌，無鞭毛，有菌毛，無芽胞，無莢膜O抗原是分類依據(jù)，可以分為4群（種），40余個(gè)血清型（包括亞型）致病性：黏附、侵襲、胞內(nèi)繁殖、細(xì)胞間擴(kuò)散志賀菌屬第20頁/共31頁 沙門菌屬第21頁/共31頁 急性消化道傳染病，我國乙類傳染病急性消化道傳染病，我國乙類傳染病 Enteric fever (typhoid fever) is the most

13、 serious form of salmonella infection which only occurs in human Carrier state is common In untreated patients, the death rate is 7% to 14% Antibiotic therapy is essential, vaccines are not effective and not widely used第22頁/共31頁1.The microbe initially invades intestinal mucosal epithelium and propag

14、ate at the local. 2.The microbe penetrates into the bloodstream to cause the first round of bacteremia with symptoms of fever, general discomfort and pain. 3.The microbe enters many organs such as liver, spleen, kidney, gall and marrow for further propagation. 4.The microbe penetrates into the blood

15、stream again to cause the second round of bacteremia with serious symptoms of high fever, swell of spleen and liver, rose-colored spots in skin, and tissue injury.第23頁/共31頁1. 致病菌S. typhi （傷寒沙門菌）S. paratyphi A （甲型副傷寒桿菌）S. schottmuelleri （肖式沙門菌）S. hirschfeldii （希式沙門菌）enteric fever Diagnosis 2. 標(biāo)本采集 Bl

16、ood first week Stool and urine from the second week on Marrow can be considered because of its high and permanent positive results.第24頁/共31頁enteric fever diagnosis3. Widal test （肥達(dá)試驗(yàn)）（肥達(dá)試驗(yàn)）a quantitative agglutination test using the known O antigen of S.typhi , and H antigens of S. typhi and S. para

17、typhi A/B to detect specific serum antibodies. For one single serum sample, The titers of anti-O antigen IgM 1:80 and/or anti-H antigen IgG 1:160. For two serum samples that collected with an interval of 57 days, 4-fold increase in titers of specific antibody.第25頁/共31頁急性胃腸炎(食物中毒，Gastroenteritis /foo

18、d-poisoning)敗血癥It is the most common Salmonella infection and usually transmitted from contaminated food. However, only a few of food poisoning-causing salmonella serotypes can produce enterotoxin.Many Salmonella serotypes can cause septicemia. This disease is commonly found in children or adult with low immunity.第26頁/共31頁QUIZ 2腸熱癥發(fā)病一周內(nèi)，進(jìn)行病原性診斷應(yīng)選擇：A.尿培養(yǎng)B.血培養(yǎng)C.糞便培養(yǎng)D