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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R.

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Presentation on theme: "Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R."— Presentation transcript:

1 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R O B I O L O G Y a n i n t r o d u c t i o n ninth edition TORTORA  FUNKE  CASE Part A 25 Microbial Diseases of the Digestive System

2 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Microbial Diseases of the Digestive System  2 nd most common illness in US  Transmitted in food and water after being shed in the feces of infected people/animals  Fecal-oral cycle can be broken by  Proper sewage disposal  Disinfection of drinking water  Proper food preparation and storage- more of our food products are grown in countries with poor sanitation

3 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Digestive System Figure 25.1

4 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Normal Microbiota  >700 species in mouth, each microliter of saliva contains millions  Enormous amounts in large intestine, up to 40% of fecal mass  Bacteroides, E. coli, Enterobacter, Klebsiella, Lactobacillus, Proteus  Most assist in enzymatic digestion and synthesis vitamins

5 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Dental Caries Figure 25.3 Unlike any exterior surface, teeth do not shed surface cells but have hard exterior which allows accumulation of microbes: plaque (biofilm) Caries-enamel and dentin are eroded exposing the pulp to bacteria, Streptococcus mutans Saliva-flushes the mouth & food “brushes” Before table sugar in 1600’s, caries not a problem Preventive care: brush, floss, cleanings, low sugar

6 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Periodontal Disease  Caries of cementum and gingivitis caused by streptococci, actinomycetes, and anerobic gram neg. Inflammation and degeneration of structures supporting the teeth  Gingivitis- bleeding gums while brushing  Periodontitis (chronic gum disease)- pus pockets form around teeth, loosening teeth  Acute necrotizing ulcerative gingivitis, Vincent’s disease, trench mouth- painful chewing, foul breath

7 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bacterial Diseases of the Lower Digestive System  Symptoms usually include diarrhea, gastroenteritis, and dysentery (severe diarrhea: bloody/ mucus) and fever. Treated with fluid and electrolyte replacement- oral hydration. Gastroenteritis- diseases causing inflammation of stomach and intestinal mucosa.  Infection is caused by growth of a pathogen:  Incubation is from 12 hours to 2 weeks.  Intoxication caused by ingestion of bacterial toxin:  Symptoms appear 1 to 48 hours after ingestion, no fever

8 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Staphylococcal Food Poisoning  Staphylococcus aureus  Improperly stored foods become contaminated by handling, bacteria grows & releases toxins.  Illness due to ingesting enterotoxin (which can withstand boiling up to 30 min.) Toxins triggers brain’s vomit reflex.  Symptoms: nausea, vomiting, diarrhea begin 1-6 hours after eating, lasts 24 hours Figure 25.6

9 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Shigellosis (Bacillary Dysentary)  Longer incubation period: 12 hours to 2 weeks, reflecting the time needed to grow in host  Shigella producing Shiga toxin  Sym : Fever, abdominal cramps, doesn’t enter blood  Trans: person to person with outbreaks in families, day- care, etc.  Shiga toxin causes inflammation and bleeding, up to 20 bowel movements/day Figures 25.7, 25.8

10 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Salmonellosis/ (Salmonella gastroenteritis)  Salmonella enterica  Incubation hours  Sym: moderate fever, nausea, cramps, diarrhea  Septic shock can occur in infants and elderly  Proper cooking poultry (& cutting board cleanup), eggs or pet reptiles Figure 25.9

11 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Typhoid Fever  Salmonella typhi  Sym: fever, malaise after 2 week incubation, lasting 2-3 weeks  Bacteria is spread throughout body in phagocytes.  Trans: by contact with human feces  1 to 3% recovered patients become carriers, harboring Salmonella in their gallbladder.  Vaccines for high risk labs, military personnel

12 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cholera  Vibrio cholerae serotypes that produce cholera toxin.  Sym: watery stools with mucus “rice water stools” & vomiting, could lose 3-5 gallons fluid/day  Trans: water Figure 25.11

13 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Noncholera Vibrios  Trans: contaminated crustaceans or mollusks: raw oysters, shrimp, crab  Sym:Abdominal pain, vomiting, burning stomach

14 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Escherichia coli Gastroenteritis  Occurs as traveler's diarrhea and epidemic diarrhea in nurseries. “boil it, peel it or don’t eat it”  50% of feedlot cattle may have enterohemorrhagic strains in their intestines, but do not suffer symptoms  Enterohemorrhagic strains such as E. coli O157:H7 produce Shiga toxin, which causes diarrhea. USDA found 90% of ground meats contaminated (cook well).  Shiga toxins can affect kidneys to cause hemolytic uremic syndrome.

15 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Campylobacter Gastroenteritis  Campylobacter jejuni  2 nd most common cause of diarrhea in US  on almost all retail chicken  60% of cattle transmit in feces and milk  Sym: Abdominal cramps, fever, diarrhea, dysentery

16 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Helicobacter Peptic Ulcer Disease  Helicobacter pylori  Sym: Peptic ulcer disease (stomach ulcers), gastritis, GI ulcers, can lead to stomach cancer  Produces ammonia, which neutralizes stomach acid allowing bacteria to colonize creating ulcer  Treated with antibiotics Figure 11.12

17 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Helicobacter Peptic Ulcer Disease Figure 25.14

18 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Yersinia Gastroenteritis  Y. enterocolitica and Y. pseudotuberculosis  Can reproduce at 4°C, so refrigeration doesn’t effect it  Usually transmitted in meat and milk  Sym: diarrhea, fever, headache, abdominal pain

19 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Clostridium Infections  Clostridium perfringens Gastroenteritis  Grow in intestinal tract, producing exotoxin  Associated with meats contaminated with intestinal contents during animal slaughter.  Clostridium difficile–associated diarrhea  Grows following antibiotic therapy  Associated with hospitalized patients and nursing home residents.

20 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bacillus cereus Gastroenteritis  Cause of outbreaks of food borne illness  Heating does not always kill the spores which germinate as the food cools  Asian rice dishes susceptible  Ingestion of bacterial exotoxin produces mild symptoms: nausea, vomiting, diarrhea

21 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Viral Diseases of Digestive System  Viruses do not reproduce in the digestive system like bacteria, they invade many organs associated with the system.

22 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mumps  Mumps virus enters through respiratory tract via saliva.  Infects parotid glands days later: swelling, fever  Prevented with MMR vaccine Figure 25.15

23 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hepatitis  Inflammation of the liver with necrosis of the hepatocytes and swelling due to a mononuclear response.  Sym: loss of appetite, malaise, fever, jaundice  At least 5 different viruses cause hepatitis  Hepatitis may result from drug or chemical toxicity, Epstein-Barr (EB)virus, cytomegalovirus (CMV)

24 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings TransmissionsymptomsChronic liver disease? Vaccine? Hepatitis AFecal-oralFever, headache, jaundice NoInactivated virus Hepatitis BParenteral, STD progress liver damage YesRecombinant Hepatitis CParenteralchronicYesNo Hepatitis DPareteral, HBV coinfection Sever liver damage, high mortality rate YesHBV vaccine Hepatitis EFecal-oralPregnant women high mortality rate No Hepatitis

25 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure Viral Gastroenteritis  Rotavirus:  90% of children under 3 have been infected  1-2 day incubation; 1 week illness  Norovirus:  “winter vomiting virus”  1-2 day incubation; 1-3 day illness  Treated with rehydration

26 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fungal diseases of the Digestive system  Some fungi produce mycotoxins.  If ingested can damage kidney, liver, blood diseases, nervous system disorders, even cancer  Diagnosis based on finding the fungi or mycotoxins in the suspected food.

27 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mycotoxins  Claviceps purpurea  Fungus grows on grains causing smut  Produces ergot: Toxin restricts blood flow to limbs; causes hallucination  Aspergillus flavus  Mold grows on grains  Produces aflatoxin: Toxin causes liver damage; liver cancer

28 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protozoan diseases of Digestive System  Ingested as resistant, infective cysts and are shed in greatly increased numbers as newly produced cysts.

29 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Giardiasis  Giardia lamblia  Flagellated, attached to intestinal wall,  Trans: contaminated water  Sym: malaise, nausea, gas, weakness, flatulance, weight loss, cramps Figure 25.18

30 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cryptosporidiosis  Cryptosporidium hominis  Transmitted by oocysts in contaminated water, mostly from cattle  Sym: headache, sweats, vomiting, severe abdominal cramps, and diarrhea Figure 25.19

31 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cyclospora Diarrheal Infection  Cyclospora cayetanensis  Transmitted by oocysts in contaminated water on berries or uncooked foods  Sym: watery diarrhea  Protist was first identified in 1993

32 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Amoebic Dysentery (Amoebiasis)  Entamoeba histolytica  Amoeba feeds on RBCs and GI tract tissues  Sym: severe dysentery containing blood/mucus  Severe bacterial infection will occur if GI wall is perforated Figure 12.18b

33 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Helminthic diseases of the Digestive System  Poor sanitation  Few symptoms  Not all make cysts  Have definitive host where adult form lives  Are multicelluar  Well adapted to host or vice versa

34 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Helminthic Diseases of the Digestive System Figure 25.21

35 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Tapeworms  Taenia  Transmitted as larve in undercooked meat  Cysticerci may develop in humans are travel to other organs (even the eye)  Diagnosed by observing feces Figure 12.27

36 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Tapeworms Figure 25.22

37 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hydatid Disease  Echinococcus granulosus  Definitive host: Dogs, wolves transmit to humans via feces  Migrate to liver, lungs, brain  Treatment is surgical Figure 25.23

38 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pinworms  Enterobius vermicularis  Definitive host: Humans  Transmitted by ingesting eggs, exit via anus (causing itching)

39 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hookworms  Larvae in soil hatched from eggs shed in feces  Larvae bore through bare skin; migrate to intestine Figure 12.30

40 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Ascariasis  Ascaris lumbricoides  Is an intestinal roundworm  Transmitted by ingesting Ascaris eggs via mouth, nose, anus  larvae penetrate into lymphatics and capillaries around intestines  larvae migrate to the pharynx, get swallowed and return to intestines to mature Figure 25.25

41 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Trichinosis  Trichinella spiralis  Larvae encyst in muscles of humans and other mammals (pork and bear)  migrate from intestines to blood and various body tissues  Transmitted by ingesting larvae in undercooked meat or handling meat Figure 25.26a–b


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