enterobacteriaceae

Question 1

Enterobacteriaceae

Answer 1

salmonella,E.coli,Yersinia pestis,Klebsiella,shigella,Proteus,Entetobacter,serratia and citrobacter.

Question 2

type

Answer 2

G-,hemolytic on blood agar,aerobe and facultative anaerobe

Question 3

E.coli

Answer 3

G-,motile peritrichous flagella,non spore former.

Question 4

toxins

Answer 4

enterotoxins and hemolysins

Question 5

2 types of enterotoxins

Answer 5

heat labile -stimulates adenyl-cyclase-cyclic adenosine monophosphate.cAMP. Heat stable-stimulates cGMP.

Question 6

Pathogenesis

Answer 6

UTI,diarrhea,pyogenic infections and septicaemia.

Question 7

diarrhea

Answer 7

6 types of diarrheagenic E.coli

Question 8

six categories

Answer 8

Enterotoxigenic (ETEC),Enteropathogenic (EPEC),Enteroinvasive ,Enterohaemorrhagic,Enteroaggregative and Diffusely adhering .

Question 9

Enterotoxigenic E.coli.(ETEC)

Answer 9

produces two toxins;heat stable (ST)and heat labile(LT).ST causes secretion of electrolytes and water into the lumen of the small intestines by stimulation of cGMP.LT causes hypersecretion of water into the intestinal lumen. ETEC have fimbriae that allow these pathogens to attach themselves to SI epithelial cells ,preventing rapid removal by peristalsis.Watery diarrhea

Question 10

Enteropathogenic

Answer 10

they have adhesive factors and have shigella like toxin then inject into enterocytes which cause effacing lesions.destruct brush border microvilli leading to subsequent diarrhea.They adhere themselves tightly to epithelial cells of small intestines by means of EPEC adhesion factor .

Question 11

Enteroinvasive

Answer 11

causes diarrhea by invading and multiplying within the intestinal cells .do not produce toxins. Ability to invade epithelial cells is associated with the presence of a large toxin.

Question 12

Enterohaemorrhagic/verocytotocin producing E.coli

Answer 12

Produces a toxib which is identical to shigella shiga toxin.named verocytotoxin because of its effect on vero cells .Possess specific ,plasmid-coded fimbriae for adhesion to epithelial cells.Cause hemorrhagic colitis.watery diarrhea with large amounts of fresh blood in stool. Causes two extraintestinal diseases-hemolytic -uremic syndrome in children and thrombotic thrombocytopenic purpura.

Question 13

Enteroaggregative E.coli

Answer 13

they adhere to epithelial cells with specific fimbriae forming clumps of bacteria with a stacked brick appearance.Cause watery and sometimes hemorrhagic diarrhea in infants amd small children . unique lesions are seen in epithelial cells. produces a toxin similar to ST in ETEC

Question 14

UTIs

Answer 14

E.coli infects the urinary tract by fimbriae which mediate adherence to uroepithelial cells. Infection manifests either in the renal pelvis or the lower urinary tract. UTIs are most common in females than in males.High incidence in pregnant women is due to hormonal changes and pressure on the UT.

Question 15

diffusely adhering E.coli

Answer 15

adhere over the entire surface of epithelial cells and usually cause disease in immunologically naive or malnourished children.

Question 16

Pyogenic infection

Answer 16

May cause superficial infections such as wound infections and abscesses or deep infections such peritonitis and meningitis.

Question 17

septicaemia

Answer 17

fever,hypotension and endotoxic shock

Question 18

lab diagnosis

Answer 18

UTI-diagnosed by collection of midstream urine as a sample and plated on a culture medium to confirm infection. Stool sample is collected and cultured in blood agar and macconkey agar plates. specimens are collected from lesions in case of pyogenic infections and cultural and biochemical tests are performed. septicaemia-isolation of bacterium by blood culture.