1/26/2016 Structure and Function of the Microbes Digestive System Learning Objective Invisible Invaders Name the structures of the digestive Amazing Allies system that contact food. CASE Chapter 25 Microbial Diseases of the Digestive System Microbial diseases are transmitted via the fecal-oral Structure and Function of the Digestive cycle System -disease results from ingesting food or water contaminated with pathogens Gastrointestinal(GI)tract or alimentary canal Pathogens enter food or water via fecal matter -Mouth Sanitation disrupts this cycle -Pharynx(throat) Need for new tests that reliably detect pathogens in -Esophagus food -Stomach CDC estimates-76 million cases of foodborne -Small and large intestine disease resulting in 5000 deaths annually in the US Accessory structures As more of our fruits and vegetables are grown in -Teeth and tongue itationis Salivary glands sa -Liver Gallbladder -Pancreas 2
1/26/2016 1 Invisible Invaders Amazing Allies Chapter 25 Microbial Diseases of the Digestive System • Microbial diseases are transmitted via the fecal-oral cycle – disease results from ingesting food or water contaminated with pathogens – Pathogens enter food or water via fecal matter • Sanitation disrupts this cycle • Need for new tests that reliably detect pathogens in food • CDC estimates – 76 million cases of foodborne disease resulting in 5000 deaths annually in the US • As more of our fruits and vegetables are grown in countries where sanitation is poor, an increase in foodborne disease is expected. Structure and Function of the Digestive System Learning Objective Name the structures of the digestive system that contact food. Structure and Function of the Digestive System • Gastrointestinal (GI) tract or alimentary canal – M th ou – Pharynx (throat) – Esophagus – Stomach – Small and large intestine • Accessory structures – Teeth and tongue – Salivary glands – Liver – Gallbladder – Pancreas
1/26/2016 The human digestive system Normal Microbiota of the Digestive Parotid (salivary) Oral cavity System gland Pharynx Learning Objective Esophagus Identify parts of the gastrointestinal tract that normally have microbiota. Liver Gallbladder ach Duodenum Pancrea Small intestine Large intestine Rectu Anus Structure and Function of the Digestive Normal Microbiota of the Digestive System System Millions of bacteria per ml of saliva Main function:breakdown of food into small Few microorganisms in the stomach molecules that are taken up -Due to HCl production ·Absorption of foods Small intestine also has few bacterio -25 tons of food pass through the GI tract in a lifetime -Rapid movement of food -Intestinal gas:swallowed N2 and microbial produced H2, -Paneth cells COz,and CHa Granule-filled phagocytic cells 80%of the immune system is located in the Produce defensins and lysozyme intestinal tract Large numbers of bacteria in the large -Gut-associated lymphoid tissue(GALT) intestine ·Lymph rodes -Anaerobes and facultative anaerobes ·Peyer's patches -Assist in enzymatic breakdown of food 100 billion (101)bacteria per gram of feces 2
1/26/2016 2 Parotid (salivary) gland Pharynx Oral cavity Tongue Teeth The human digestive system Esophagus Liver Gallbladder Stomach Duodenum Pancreas Small intestine Large intestine Anus Rectum Structure and Function of the Digestive System • Main function: breakdown of food into small molecules that are taken up • Absorption of foods – 25 tons of food pass through the GI tract in a lifetime – Intestinal gas: swallowed N2 and microbial produced H2, CO2, and CH4 • 80% of the immune system is located in the i t sti l t t intestinal tract – Gut-associated lymphoid tissue (GALT) • Lymph nodes • Peyer's patches Normal Microbiota of the Digestive System Learning Objective Identify parts of the gastrointestinal tract that normally have microbiota. Normal Microbiota of the Digestive System • Millions of bacteria per ml of saliva • Few microorganisms in the stomach – Due to HCl production • Small intestine also has few bacteria – Rapid movement of food – Paneth cells • Granule-filled phagocytic cells • Produce defensins and lysozyme • Large numbers of bacteria in the large intestine – Anaerobes and facultative anaerobes – Assist in enzymatic breakdown of food • 100 billion (1011) bacteria per gram of feces
1/26/2016 Bacterial Diseases of the Mouth Dental Caries(Tooth Decay) ·Dental plaque Learning Objective -Biofilms involved in the formation of dental caries Describe the events that lead to dental 700 species of bacteria in the oral cavity caries and periodontal disease. -Streptococcus mutans is the most important cariogenic organism Gram-positive coccus;falcultative anoerobe Converts sucrose to lactic acid which attacks the tooth enamel Produces dextran,a polysaccharide that forms plaque Plagues attract other cariogenic bacteria -Mainly,Streptococci:filamentous Actinomyces -But may harbor over 400 bacterial species A healthy human tooth Streptococcus mutans -Enamel Crowr -Dentin -Pulp cavity Gingival crevice Gum (gingiva) Periodontal ligament Bone Root Cementum Root canal Blood vessels and nerves in pulp Glucose broth Sucrose broth cavity
1/26/2016 3 Bacterial Diseases of the Mouth Learning Objective Describe the events that lead to dental caries and periodontal disease. A healthy human tooth Crown Enamel Dentin Pulp cavity Neck Root Gingival crevice Gum (gingiva) Periodontal ligament Bone Cementum Root canal Blood vessels and nerves in pulp cavity Dental Caries (Tooth Decay) • Dental plaque – Biofilms involved in the formation of dental caries • 700 species of bacteria in the oral cavity – Streptococcus mutans is the most important cariogenic organism • Gram-positive coccus; falcultative anaerobe • Converts sucrose to lactic acid which attacks the tooth enamel • Produces dextran, a polysaccharide that forms plaque • Plaques attract other cariogenic bacteria – Mainly, Streptococci; filamentous Actinomyces – But may harbor over 400 bacterial species Streptococcus mutans Glucose broth Sucrose broth
1/26/2016 Dental Caries (Tooth Decay) Periodontal Disease Caries penetrate from enamel into the Gingivitis dentin -Inflammation and infection of the gums -Half of the adult population has experienced this Appears in a few weeks if brushing is stopped -Caused by streptococci,actinomycetes,and anaerobic Decay can reach pulp,which contains the gram-negative bacteria blood supply and nerve cells ·Periodontitis -May advance to the soft tissues,leading to ahscesses Introduction of table sugar in the diet is -Caused by Porphyromonas correlated with the level of dental caries Acute necrotizing ulcerative gingivitis (trench mouth) -Coused by Prevotella intermedia The stages of tooth decay The stages of periodontal disease Advanced decay Plague is not permeable to saliva and lactic acid produced is not diluted or neutralized. Acid production results in softening of the eramel,which is low in fluoride and is more susceptible to the acid
1/26/2016 4 Dental Caries (Tooth Decay) • Caries penetrate from enamel into the dentin – Caused by gram-positive rods and filamentous bacteria • Decay can reach pulp, which contains the blood supply and nerve cells – May advance to the soft tissues, leading to a c bs esses • Introduction of table sugar in the diet is correlated with the level of dental caries The stages of tooth decay Enamel Dentin P l Plaque Decay Root canal therapy Healthy tooth with plaque Decay in enamel Advanced decay Decay in dentin Decay in pulp Pulp Bone Root plaque • Plaque is not permeable to saliva and lactic acid produced is not diluted or neutralized. • Acid production results in softening of the enamel, which is low in fluoride and is more susceptible to the acid Periodontal Disease • Gingivitis – Inflammation and infection of the gums – Half of the adult population has experienced this – Appears in a few weeks if brushing is stopped – Caused by streptococci, actinomycetes, and anaerobic gram-negative bacteria • Periodontitis – Bone and tissue supporting the teeth are destroyed – Caused by Porphyromonas • Acute necrotizing ulcerative gingivitis (trench mouth) – Caused by Prevotella intermedia The stages of periodontal disease Plaque Tooth Gum (gingiva) Bone Cementum Periodontal ligament Healthy Gingivitis Periodontal Periodontitis q ligament Healthy gingivae Gingivitis Periodontal pockets Periodontitis
1/26/2016 Bacterial Diseases of the Lower Digestive System Dysentery-diarrhea accompanied with blood or mucus Learning Objective Gastroenteritis -inflammation of the List the causative agents,suspect foods, stomach and intestinal mucosa signs and symptoms,and treatments for .In developing countries,diarrhea is a staphylococcal food poisoning. shigellosis,salmonellosis,typhoid fever. major factor in infant mortality(1 out of cholera,gastroenteritis,and peptic 4 children die) ulcer disease. Disease of the digestive system are often related to food ingestion. Staphylococcal Food Poisoning Disease of the digestive system are of 2 types -infection (Staphylococcal Enterotoxicosis) -intoxication Enterotoxin produced by Staphylococcus aureus Infection occurs when a pathogen enters the GI -Serological type A tract and multiplies Coagulates blood plasma -grow in the mucosa or penetrate to other organs -Toxin is not killed by boiling -GIdisturbance is delayed while bacteria multiply fever usually occur S.aureus inhabits nasal passages Intoxication is due to ingestion of a toxin Toxins produced when the organism -sudden appearance:no fever is allowed to incubate in food (temperature Both type es are associated with abdominal cramps, abuse) nausea,diarrhea,and vomiting -s aureus outo Diarrhea and vomiting are designed to rid the body of the harmful substance. Phage typing traces sources of contamination
1/26/2016 5 Bacterial Diseases of the Lower Digestive System Learning Objective List the causative agents, suspect foods, signs and symptoms, and treatments for staphylococcal food poisoning, shigellosis, salmonellosis, typhoid fever, ch l st t itis d ti h olera, gastroen teritis, and pepti c ulcer disease. • Disease of the digestive system are of 2 types – infection – intoxication • Infection occurs when a pathogen enters the GI tract d l i li and multiplies – grow in the mucosa or penetrate to other organs – GI disturbance is delayed while bacteria multiply; fever usually occurs • Intoxication is due to ingestion of a toxin – sudden app ; f earance; no fever • Both types are associated with abdominal cramps, nausea, diarrhea, and vomiting • Diarrhea and vomiting are designed to rid the body of the harmful substance. • Dysentery – diarrhea accompanied with blood or mucus • Gastroenteritis – inflammation of the stomach and intestinal mucosa • In developing countries, diarrhea is a major factor in infant mortality (1 out of 4 children die) • Disease of the digestive system are often related to food ingestion. Staphylococcal Food Poisoning (Staphylococcal Enterotoxicosis) • Enterotoxin produced by Staphylococcus aureus – Serological type A • C l t bl d l Coagulates blood plasma – Toxin is not killed by boiling • S. aureus inhabits nasal passages • Toxins produced when the organism is allowed to incubate in food (tem perature abuse) – S. aureus outgrows most bacteria in high osmotic pressure and high temperature (600C for 30 mins) • Phage typing traces sources of contamination