MOD 6 FULL

• Colon bacillus


  What is the common name of E.coli?
• Large intestine; vagina and urethra


  Habitat and transmission: E.coli is a normal flora of? And may colonize
• Acquired during birth and by fecal-oral route


  E coli is aquired during.
• 1. Urinary tract infection

  2. Neonatal meningitis and septicemia

  3. Gastroenteritis


  Pathogenesis and clinical manifestations of E.coli
• Urinary tract infection

  Commonly caused by E. coli, in approximately 90% of cases
• Uti;

  a. short urethra

  
  

  b. proximity of the urethra to the anus

  
  

  c. colonization of the vagina by members of the fecal flora


  This clinical manifestation of e coli Occurs primarily in women, a finding attributed to 3 features:
• Results from endogenous spread of the bacteria from the large intestine as resident flora, and mechanically introduced into the urethra (e.g., careless personal hygiene, sexual intercourse, or catheterization);

  What type of spread does uti manifest?
• cystitis


  In uti, the colonization facilitates the ascent of bacteria from the urethra into the bladder causing
• pyelonephritis results


  In uti, f the invading bacteria pass up the ureters to the kidney,
• a. Urinary frequency - the urge to pass urine more often than usual

  
  

  b. Dysuria - painful urination

  
  

  c. Hematuria - the presence of blood in urine

  
  

  d. Pyuria - the presence of leukocytes, commonly referred to as pus, in the urine

  
  

  e. Flank pain - pain in one side of the body between the upper belly area (abdomen) and the back; associated with upper tract infection, a sign of kidney involvement


  Signs and symptoms of uti atleast 5
• a. Urinary frequency - the urge to pass urine more often than usual

  Urinary frequency
• Dysuria


  painful urination
• Pyuria

  the presence of leukocytes, commonly referred to as pus, in the urine
• Flank pain

  pain in one side of the body between the upper belly area (abdomen) and the back; associated with upper tract infection, a sign of kidney involvement
• presence of blood in urine

  Hematuria
• a. P pili (P fimbriae)

  Endotoxin

  Hemolysin

  Aerobactin

  Capsular polysaccharide


  What are the virulence factors in UTI?
• P pili (P fimbriae)

  Named for their ability to bind to and agglutinate human RBCs carrying the P blood group antigen
• Capsular polysaccharide

  The determinant of the K antigen
• Endotoxin

  Resides in the cell wall and consists of the lipid A of the LPS
• a. P pili (P fimbriae)


  Allow the bacteria to attach to the urinary epithelial mucosa and not be washed out with urine flow
• Hemolysin

  Inhibit phagocytosis and chemotaxis of certain white blood cells
• Capsular polysaccharide

  s antiphagocytic and inhibits the opsonizing and lytic activities of complement because of the identity of the capsular polysaccharides and the host carbohydrates
• Aerobactin

  A siderophore, .i.e., iron chelating agent, enabling E. coli to bind and transport iron for use by bacteria in iron-poor environments such as the urinary tract
• Hemolysin


  Cytolysin that creates pores in eukaryotic cell membranes
• Endotoxin


  Responsible for much of the morbidity and mortality resulting from infections associated with these bacteria
• Group B streptococci

  • E. coli - a major cause of meningitis and septicemia and meningitis among newborns, along with
• vertical transmission from the birth canal just before or during delivery, when the mother's vagina is heavily colonized or infection may also result if contamination of the amniotic fluid occurs


  Neonatal meningitis and septicemia is Acquired by newborns by
• a. K1 antigen (capsular polysaccharide)

  b. S fimbriae

  c. Siderophore


  What are the Virulence factors of neonatal meningitis and septicemia
• extraintestinal infections, mostly nosocomial, i.e., in hospitalized patients whose normal defense mechanisms have been breached.

  
  

  These include wound infections, and pneumonia.

  E. coli is also an important cause of e
• Mechanical introduction

  careless personal hygiene

  sexual intercourse

  catheterization

  endogenous spread of uti includes
• Mother's vagina is heavily colonized

  Contaminated amniotic fluid


  Vertical transmission of neonatal meningitis
• S fimbriae

  Bind to vascular endothelium and epithelial lining of brain tissues
• Siderophore

  Allows the bacteria to chelate iron
• K1 antigen (capsular polysaccharide)

  Cross-reacts with the group B capsular polysaccharide of Neisseria meningitides
• Does not stimulate antibody production (Sialic)
• a. Enterotoxigenic E. coli (ETEC)

  b. Enteropathogenic E. Coli (EPEC)

  c. Enteroinvasive E. coli (EIEC)

  d. Enterohemorrhagic E. coli (EHEC)

  e. Enteroaggregative E. coli (EAEC or EAggEC)

  
  

  
  

  
  

  enterovirulent E. coli or diarrheogenic E. coli

  5 pathotypes of diarrheagenic E. coli
• Weanling diarrhea

  Traveler's diarrhea


  Associated with two clinical syndromes: of ETEC
• Weanling diarrhea

  - among children in tropical

  
  

  and subtropical climates, especially in developing countries, when they are being weaned off nursing and start to take food and drinks other than mother's milk
• Montezuma's revenge, Delhi belly, or turista)


  Traveler's diarrhea (also referred to as
• Traveler's diarrhea


  when a person eats food, or drinks water contaminated with ETEC, esp. during travel to developing countries, to an area with poor public hygiene, inadequate sanitation, or reduced availability of sources of potable water.