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Miroslav Votava Agents of digestive system infections – I

Institute for Microbiology, Medical Faculty of Masaryk University and St. Anna Faculty Hospital in Brno. Miroslav Votava Agents of digestive system infections – I The 3rd l ecture for 3rd-year students of dentistry 6th December , 20 10. Respiratory viruses – revision.

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Miroslav Votava Agents of digestive system infections – I

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  1. Institute for Microbiology, Medical Faculty of Masaryk University and St. Anna Faculty Hospital in Brno Miroslav Votava Agents of digestive system infections – I The 3rd lecture for 3rd-year students of dentistry 6thDecember, 2010

  2. Respiratory viruses – revision • The most important and most common: • influenzavirus A a B • adenoviruses • RSV and metapneumoviruses • parainfluenzaviruses (type 1+3 = Respirovirus, type 2+4 = Rubulavirus) • rhinoviruses • coronaviruses (incl. SARS agent)

  3. Other respiratory agents of virological interest – revision • Bacterial agents causing atypicalpneumoniae (but diagnosed in virological laboratories): • Mycoplasmapneumoniae– the most common • Coxiellaburnetii – Q-fever • Chlamydiapsittaci – ornithosis • Chlamydiapneumoniae

  4. Etiology of epiglottitis – revision • Epiglottitis acuta: Serious disease – medical emergency The child may suffocate! • Practically one and only important agent: Haemophilus influenzae type b

  5. Etiology of laryngitis and tracheitis – revision • Again respiratoryviruses but other than agents of nasopharyngitis: parainfluenza and influenzaA viruses & RSV • Bacteria: C. pneumoniae, possibly Mycopl. pneumoniae, secondarily: S. aureus and Haem. influenzae laryngotracheitis pseudomembranosa (croup): Corynebacterium diphtheriae

  6. Etiology of bronchitis – revision • Acute bronchitis: Viruses:influenza, parainfluenza, adenoviruses, RSV Bacteria, secondarily after viruses: pneumococci, Haem. influenzae, Staph. aureus, Moraxella catarrhalis Bacteria, primarily: Mycoplasmapneumoniae, Chlamydia pneumoniae, Bordetellapertussis • Chronic bronchitis (cystic fibrosis): • Pseudomonas aeruginosa, Burholderia cepacia

  7. Etiology of bronchiolitis – revision • Isolated bronchiolitis in newborns and infants only: Pneumovirus (= respiratory syncytial virus = RSV) Metapneumovirus

  8. Different types of pneumoniaehave different etiologies • Acute – community-acquired pneumoniae • in originally healthy (1) • adults (2) • children (3) • in debilitated persons (4) • after a contact with animals (5) • Acute – nosocomialpneumoniae – VAP = ventilator-associated (6) • early (7) • late (8) –others (9) 3. Subacute and chronic pneumoniae(10)

  9. Etiology of pneumoniae I– revision • Acute,community-acquired, in healthy adults • bronchopneumonia and lobar pneumonia: • Streptococcus pneumoniae • Staphylococcus aureus • Haemophilus influenzae type b • atypicalpneumonia: • Mycoplasma pneumoniae • Chlamydia pneumoniae • Influenza A virus (during an epidemic only)

  10. Etiology of pneumoniae II– revision • Acute, community-acquired, in healthy children • Bronchopneumonia: • Haemophilus influenzae • Streptococcus pneumoniae • Moraxellacatarrhalis • In newborns: Streptococcus agalactiae enterobacteriae • atypical pneumonia: • respiratory viruses (RSV, infl. A, adenoviruses) • Mycoplasma pneumoniae • Chlamydia pneumoniae • in newborns: Chlamydia trachomatis D-K

  11. Etiology of pneumoniae III – revision • Acute, community-acquired, in debilitated individuals: • pneumococci, staphylococci, haemophili • Klebsiellapneumoniae (alcoholics) • Legionellapneumophila • In more serious immunodeficiency: • Pneumocystis jirovecii • CMV • atypical mycobacteria • Nocardia asteroides • aspergilli, candidae

  12. Etiology of pneumoniae IV – revision • Acute, community-acquired, after a contact with animals: • Bronchopneumonia • Pasteurella multocida • Francisella tularensis (tularemia) • Atypical pneumonia • Chlamydia psittaci (ornithosis) • Coxiella burnetii (Q-fever)

  13. Etiology of pneumoniae V– revision • Acute, nosocomial: • VAP (ventilator-associated pneumonia) • early (up to the 4th day of hospitalization): sensitive communitystrains of respiratory agents • late (from the 5th day of hospitalization): resistant hospital strains • Others • viruses (RSV, CMV) • legionellae

  14. Etiology of pneumoniae VI– revision • Subacute and chronic: • aspiration pneumonia and lung abscesses • Prevotella melaninogenica • Bacteroides fragilis • peptococci and peptostreptococci • lung tuberculosis and mycobacterioses • Mycobacterium tuberculosis • Mycobacterium bovis • atypical mycobacteria(e.g. the complex M. avium–M. intracellulare) …

  15. Digestivesystem • a microbiologist´s dreamland • a fruitful microbial garden • its both ends are the „buggiest“ parts of the body • in the colon: approx. 1012 bacteria/g • normal colonic flora: 99 % anaerobes(Bacteroides, Fusobacterium, Clostridium, Peptostreptococcus), only 1 % enteric bacteria (mostly E. coli)& enterococci

  16. Mouth cavity – I Normal flora: • viridans (= α-haemolytic) streptococci (e.g. Streptococcus salivarius) • oral neisseriae (e.g. Neisseria subflava) • haemophili of very low pathogenicity (e.g. Haemophilus parainfluenzae) Dental plaque: adherent microbial layer at the tooth surface consistingof living and dead bacteria and their products together with components from the saliva In essence, dental plaque is a biofilm It cannot be washed off, only mechanically removed

  17. Mouth cavity – II Dental caries: chronic infection caused by normal oral flora → localized destruction of tooth tissue Etiology: mouth microbes (mostly Strept.mutans) making acids from sucrose in food Thrush (in Latin soor): Candida albicansItoccursmostly in newborns Herpetic stomatitis: primary infection with HSV 1 Ludwig´s angina: polymicrobial anaerobic infection of sublingual and submandibular spaces (Porphyromonas, Prevotella etc.)

  18. Oesophagus Infections never occur in previously healthy individuals Only in severely immunocompromised persons (AIDS or after chemotherapy): • Candida albicans • Cytomegalovirus (CMV)

  19. Stomach Stomach = a sterilization chamber killing most of the swallowed microbes by means of HCl Exception: Helicobacter pylori It produces a potent urease and by splitting tissue urea it increases pH around itself (1 molecule of urea → 1 CO2 + 2 NH3) H. pylori causes • chronic gastritis • peptic ulcers (Warren & Marshall, Nobel price in 2005)

  20. Biliary tree & the liver – I Acute cholecystitis (colic, jaundice, fever): obstruction due to gallstones Etiology: intestinal bacteria (E. colietc.) Complication: ascending cholangitis Chronic cholecystitis: the most dangerousagent is Salmonella Typhi (carriers of typhoid fever) Granulomatous hepatitis: Q fever, tbc, brucellosis

  21. Biliary tree & the liver – II Parasitic infections of the liver: Amoebiasis (Entamoeba histolytica: liver abscess) Malaria (the very first, clinically silent part of the life cycle of malaric plasmodia) Leishmaniasis (Leishmania donovani:kala-azar, L. infantum) Schistosomiasis (eggs of Schistosoma japonicum, less often S. mansoni)

  22. Systemic infections which start in the digestive tract Enteric fever (typhoid fever and paratyphoid fever): Salmonella Typhi, Salmonella Paratyphi A, B and C Listeriosis: Listeria monocytogenes Peritonitis: colonic flora (Bacteroides fragilis + other anaerobes + mixture of facultative anaerobes) Viral hepatitis: HAV, HBV, HCV, HDV, HEV

  23. Small and large intestine Bacterial overgrowth syndrome: After surgery, during depressed peristalsis or gastric achlorhydria bacteria may overgrow in the small intestine → steatorrhea, deficiency of vitamin B12, diarrhea, malabsorption of vitamins A and D Diarrhea: increase in daily amount of stool water – common intestinal response to many agents Dysentery: acute inflammation of the colon → abdominal pain & small-volume stools with blood, pus and mucus

  24. Etiology of diarrheal disease Infectious etiology: • Bacterial (most frequent) • Viral • Parasitic • Mycotic Non-infectious etiology: • Food poisoning . . .

  25. Homework 3Who painted this picture and what is its name?

  26. Answer and questions The solution of the homework and possible questions please mail (on 6.30 a.m. at the latest) to the address mvotava@med.muni.cz Thank you for your attention

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