Shigella

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Shigella

  1. 1. LECTURE SHIGELLA SPECIES & FOOD POISONING
  2. 2. GENERAL CHARACTERISTICS Gram negative rods, non-lactose fermenters ( pale colonies on Mac Conkeys medium) Capsule "K" and Somatic ``O`` antigen Exotoxins: 1. Shiga toxin. 2. Entero toxin (similar to E. coli LT)
  3. 3. 1. S. dysenteriae A Type 1 (Asia, Japan, Central America) May go systemic. Type 2 (Europe) Less severe form 2. S. flexneri B Most common. Worldwide. 3. S. boydi C Worldwide. 4. S. sonnei D Most common in USA (2-year olds)
  4. 4. DISEASES •All four species cause dysentery. Abdominal pain, Bloody stool, Diarrhea
  5. 5. DISEASES • All four species cause dysentery. Abdominal pain, Bloody stool, and Diarrhea
  6. 6. EPIDEMIOLOGY: • Reservoir: Strict human pathogen. Human colon, food, feces, but doesn't live long outside of host. `` Food, fingers, flies and feces`` • Infectious dose: less than 100 organisms . • Incubation period: 1-4 days . • Oral >>> Stomach >>> Small Intestine >>>large intestine >>>Feces>>>Oral
  7. 7. PATHOGENESIS: • Invasion of colonic epithelial cells - Reproduction (108 to 109/ml) within 12 hours in distal small bowel. In 1 to 4 days invades large intestine. • Ulceration (purulent with PMN's) • <<Not systemic and usually self-limiting, lasts a few days to a month>>
  8. 8. DIAGNOSIS: • Selective media needed for isolation. • Stool culture for isolation. • Plate rapidly, organisms die. • Selective media: Mac Conkey agar, (XLD) Xylose-Lysine-Deoxycholate agar , EMB or Salmonella Shigella (SS) agar
  9. 9. TREATMENT • Ampicillin, Trimethoprim, Sulfamethoxazole, tetracycline, etc. • Protection: Antibodies in blood IgG. Secretary Ig A (short-lived). • Herd Immunity can occur: No good immunization available
  10. 10. Gastrointestinal Tract Infections and Food Poisoning. • Food borne and Water borne diseases. • Varieties of Microbes cause G.I.T. infections. • MUSHROOMS FUNGI PARASITES BACTERIA & VIRUSES
  11. 11. • Worldwide Diarrheal diseases second only to Respiratory diseases as cause of Adult death. • Leading cause of child death in Asia, Africa and South America. Each year 5 million children (13,600/day) die of Diarrheal diseases.
  12. 12. HOW TO INVESTIGATION OF FOOD POISONING ? SOURCE SYMPTOMS INCUBATION PERIOD MECHANISM ``TREATMENT PREVENTION AND CONTROL``
  13. 13. 1. Staph. Aureus gram positive coccus Dairy & bakery products like, mayonnaise, sauces pastries ice creams, processed meat etc. Salads also common source. Heat stable Rapid onset with short duration1-8 hours to 24 hours. Vomiting, little or no diarrhea, no fever. Symptomatic. Hygienic measures.
  14. 14. 2. Bacillus cereus gram positive rod. Food poisoning: Bacteria or Enterotoxin in food. ``Reheated fried rice or Chinese rice`` Heat-stable Enterotoxin …mainly vomiting. Heat-labile Enterotoxin mainly diarrhea by stimulation of adenylate cyclase. (increases cAMP). Incubation period 2-16 hours. Vomiting or Diarrhea; no fever. Symptomatic: Rice should not be reheated. Sauces creams prepared and stored properly.
  15. 15. 3. Clostridium perfringens gram positive rods Spores in soil and food Enterotoxin. Heat-labile protein. Inhibits glucose transport & damages int. epithelium causes protein loss into the intestinal lumen. Diarrhea; little or no vomiting; no fever.8-16 hours incubation Symptomatic No antibiotics , Foods adequately cooked.
  16. 16. 4. Clostridium botulinum gram positive rod. Canned foods. In newborns ingestion of honey as`` GHUTTI`` • Protein prevents release of acetylcholine at neuro-muscular junction causing a flaccid paralysis; Botulism; flaccid Paralysis of muscles; ptosis of eyelids, facial muscle paralysis. • Heat labile toxin proper cooking will destroy. • Trivalent Antitoxin AB&E along with respiratory support. Proper sterilization and vacuum packed cooked food for canning. • Discard swollen cans.
  17. 17. 5. Vibrio cholera gram negative curved rod Ingestion with contaminated water or food.(shellfish, shrimp, oysters) Contaminated water supplies, Lack of septic tanks springs, wells become infected during floods. Cholera; Severe Diarrhea; Rice water stools; Massive IV fluids required. Strict Public health measures, Boiled or chlorinated water in epidemics. Cholera Pots. Tetracyclines shorten exertion of bacteria. Rehydration.
  18. 18. 6. Enterotoxigenic (ETEC) E. coli contaminated water or cells. Traveler's Diarrhea; watery, self limited diarrhea, vomiting, cramps, nausea, low-grade fever, 1-3 days duration. Also known as Turista Antibiotics not advocated. Septran can shorten illness. Rehydration. 7. Enteropathogenic. (EPEC) E.coli (EPEC) Ingestion of contaminated water or food. No toxins24-48 hours Infant diarrhea with fever, nausea, vomiting nonbloody diarrhea. Treatment Same
  19. 19. 9. Enteroaggregative (EAggEC) E. coli Ingestion contaminated water. Persistent watery diarrhea with vomiting. and dehydration in Infants. Can lead to bloody stools. Treatment same 10. Enteroinvasive (EIEC) same 11. Enterohemmorhagic (EHEC) E. coli (hemolytic uremic syndrome) [HUS]).
  20. 20. 12. E. coli strain O157:H7, which is infamous for causing widespread outbreaks. which is infamous for causing widespread `` Jack-in-the-Box outbreak ``
  21. 21. 13, Clostridium difficile gram positive rod.Treatment of a patient with antibiotics loss of normal flora allowing Cl. difficile to overgrow. Especially after Abdominal surgery, abrupt onset of bloody diarrhea fever and abdominal pain. Antibiotic associated or Pseudomembranous colitis. Causative agent should be withdrawn esp. Clindamycin. Treatment with Vancomycin Fluid replacement
  22. 22. 14. Vibrio parahemolyticus slightly curved gram negative rod. Ingestion of contaminated undercooked or raw seafood. Organisms grow in gut and invade epithelium Most common cause of diarrhea in Japan. Pseudo membranous colitis. Self limiting Avoid undercooked or contaminated sea food.
  23. 23. 14. Rotavirus fecal-oral contamination No toxins Winter diarrhea-fever, abdominal pain and Vomiting (mostly in Infants.) Fluid replacement, Prevent infection from spreading in nurseries. 15. Norwalk Agent fecal-oral contamination. No toxins. Summer diarrhea- fever, abdominal pain, diarrhea, and vomiting. Rehydration
  24. 24. 16 . Giardia lamblia Intestinal parasite Ingestion of Contaminated water or food. Tooth brushes . ``Upper part of intestine `` Duodenum Attach to microvillus of small intestine Giardiasis- fatty, foul smelling diarrhea, Flatulence(gas) , Metronidazole 10 gms in 10 days Secondal short treatment 4 tabs, Symptomatic.
  25. 25. 17. Shigella S.sonnei S. flexneri S. boydii, S. dysenteriae . Transmitted by the 4-F's;`` food, fingers, feces, and flies.`` Fever and cramping Abdominal pain is Prominent. Diarrhea usually appears after 48hours, with dysentery supervening about 2 days later. Amoxil and Septran in severe cases. Electrolyte and fluid replacement
  26. 26. 18 . Salmonella typhi, Salmonella paratyphi A, B, and C, Salmonella cholerasuis : Ingestion of fecally contaminated food or water. Able to survive in neutrophils. Typhoid fever, paratyphoid or enteric fever. abdominal pain and discomfort, constipation bloody feces nausea, vomiting, Diarrhea Antibiotics like Amoxil, Chloramphenicol Quinolones etc. Soft diet. Fluids
  27. 27. 19. Salmonella enteriditis 1500 serotypes gram negative rod Fecal-oral transmission contaminated water, Food (poultry, eggs, or dairy products). Nausea vomiting Diahorrea Antibiotics not indicated except in infants Fluid and electrolyte replacement.
  28. 28. 20 . Campylobacter jejuni coma or seagull-shaped gram negative rod. Animal to human transmission, contaminated water, raw milk and food especially poultry. Verotoxin - similar to the Shigella toxin .2-10 days bloody diarrhea. Self limiting, usually recovers in 5-10 days. Erythromycin in severe cases
  29. 29. 21.Yersinia enterocolitica and Yersinia pseudotuberculosis. Spread via contaminated meat or milk. Ingestion of uncooked or undercooked meat invasins allows entry in cells in the Payer’s patches, diarrhea, fever, abdominal pain , If severe treat with Gentacin. Fluid and electrolyte replacement
  30. 30. 22. Francisella tularensis Ingestion of uncooked or under cooked mammals. Tularemia a zoonosis disease, of bird fanciers. Present in bird droppings. No toxins. Continuous fever (without chills or sweating (muscle pains), Severe headaches, Hepatosplenomegaly Usually no vomiting or Diarrhea. Myalgias Streptomycin. Symptomatic treatment
  31. 31. 23 . Helicobacter pylori curved rod, fecal oral spread Peptic ulcer, Gastritis results in dyspepsia, Cramps, nausea, vomiting and Flatulence. • Triple drug therapy, Antacids Bismuth sulphate.
  32. 32. 24. Entamoeba histolytica parasite protozoa Transmitted by the 4-F's; food, fingers, feces, and flies dysentery= bloody Mucoid diarrhea, flask shaped ulcers in the Colon. Can cause Liver Abscess. Metronidazole Surgery may be required.
  33. 33. 25. Listeria monocytogenes present all around in the environment. It has also been found in low numbers in many foods. In certain foods, such as cheeses and pâtés, it may be present in higher numbers. Eating foods containing high levels of Listeria monocytogenes is generally the cause of illness
  34. 34. Prevention: ``Hand washing is the most effective means of preventing diarrheal infections that are passed from person to person. `` Dirty hands carry infectious germs into the body when a child bites his nails or puts any part of his hands into his mouth. Children should wash their hands frequently, especially after using the toilet and before eating. • Clean bathroom surfaces .
  35. 35. Food and water also can carry infectious germs: 08 tips 1. Be sure to wash fruits and vegetables thoroughly before eating. 2. Wash kitchen counters and cooking utensils after they have been in contact with raw meat, especially poultry. 3. Refrigerate meats as soon as possible after bringing them home from the supermarket, and cook them until they are no longer pink. 4. After meals, refrigerate cooked leftovers as soon as possible.
  36. 36. 5. When traveling, never drink from streams, springs. 6. In our country , it may be safer to drink only bottled water and drinks rather than water from a tap. 7. Exercise caution when buying prepared foods from street vendors, especially if no local health agency oversees their operations. 8. Pets, especially reptiles, can spread germs if their feeding areas are not separate from family eating areas.
  37. 37. THANK YOU FOR YOUR PATIENCE .

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