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 B 25 Microbial Diseases of the Digestive System

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Escherichia coli Gastroenteritis  Occurs as traveler's diarrhea and epidemic diarrhea in nurseries.  50% of feedlot cattle may have enterohemorrhagic strains in their intestines.  Enterohemorrhagic strains such as E. coli O157:H7 produce Shiga toxin.  O = cell wall antigen  H = flagellar antigen

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Campylobacter Gastroenteritis  Campylobacter jejuni  Usually transmitted in cow's milk

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Helicobacter Peptic Ulcer Disease  Treated with antibiotics  H. pylori causes stomach cancer Figure 11.12

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

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Yersinia Gastroenteritis  Y. enterocolitica and Y. pseudotuberculosis  Can reproduce at 4°C  Usually transmitted in meat and milk

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

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bacillus cereus Gastroenteritis  Ingestion of bacterial exotoxin produces mild symptoms.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mumps  Mumps virus  Enters through respiratory tract  Infects parotid glands  Prevented with MMR vaccine Figure 25.15

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hepatitis  Inflammation of the liver.  Hepatitis may result from drug or chemical toxicity, EB virus, CMV, or the hepatitis viruses.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings TransmissionCausative agentChronic liver disease? Vaccine? Hepatitis AFecal-oralPicornaviridaeNoInactivated virus Hepatitis BParenteral, STD HepadnaviridaeYesRecombinant Hepatitis CParenteralFiloviridaeYesNo Hepatitis DPareteral, HBV coinfection DeltaviridaeYesHBV vaccine Hepatitis EFecal-oralCaliciviridaeNo Hepatitis

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hepatitis B Virus Figure 25.16

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure Viral Gastroenteritis  Rotavirus:  3 million cases annually  1-2 day incubation; 1 week illness  Norovirus:  50% of U.S. adults have antibodies  1-2 day incubation; 1-3 day illness  Treated with rehydration

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mycotoxins  Mycotoxins are produced by some fungi  Claviceps purpurea  Grows on grains  Produces ergot  Toxin restricts blood flow to limbs; causes hallucination  Aspergillus flavus  Grows on grains  Produces aflatoxin  Toxin causes liver damage; liver cancer

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Giardiasis  Giardia lamblia  Transmitted by contaminated water  Diagnosed by microscopic examination of stool for ova and trophozoite  Treated with metronidazole Figure 25.18

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cryptosporidiosis  Cryptosporidium hominis  Transmitted by oocysts in contaminated water  Diagnosed by acid-fast staining of stool or presence of antibodies by FA or ELISA  Treated with oral rehydration Figure 25.19

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cyclospora Diarrheal Infection  Cyclospora cayetanensis  Transmitted by oocysts in contaminated water  Diagnosed by microscopic examination for oocysts  Treated with trimethoprim and sulfamethoxazole

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Amoebic Dysentery  Entamoeba histolytica  Amoeba feeds on RBCs and GI tract tissues  Diagnosis by observing trophozoites in feces  Treated with metronidazole Figure 12.18b