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 Lecture for 3rd-year students 3rd October, 2014

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)

Other respiratory agents of virological interest – revision Bacterial agents causing atypical pneumoniae (but diagnosed in virological laboratories): Mycoplasma pneumoniae – the most common Coxiella burnetii – Q-fever Chlamydia (Chlamydophila) psittaci – agent of ornithosis & psittacosis Chlamydia (Chlamydophila) pneumoniae

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

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

Etiology of bronchitis – revision Acute bronchitis: Viruses: influenza, parainfluenza, adenoviruses, RSV Bacteria, secondarily after viruses: pneumococci, Haem. influenzae, Staph. aureus, moraxellae (again “the gang of four”) Bacteria, primarily: Mycoplasma pneumoniae, Chlamydia pneumoniae, Bordetella pertussis Chronic bronchitis (cystic fibrosis): Pseudomonas aeruginosa, Burkholderia cepacia

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

Different types of pneumoniae – revision Acute – community-acquired pneumonia in originally healthy adults children in debilitated persons after a contact with animals Acute – nosocomial pneumonia – VAP = ventilator-associated early late – others 3. Subacute and chronic pneumonia

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

Etiology of pneumoniae II – revision Acute, community-acquired, in healthy children bronchopneumonia: Haemophilus influenzae type b ( vaccination!) Streptococcus pneumoniae Moraxella catarrhalis In newborns: Streptococcus agalactiae enterobacteriae atypical pneumonia: respiratory viruses (RSV, infl. A, adenoviruses) Mycoplasma pneumoniae Chlamydia pneumoniae in newborns: Chlamydia trachomatis D-K

Etiology of pneumoniae III – revision Acute, community-acquired, in debilitated individuals: pneumococci, staphylococci, haemophili Klebsiella pneumoniae (alcoholics) Legionella pneumophila In more serious immunodeficiency: Pneumocystis jirovecii cytomegalovirus (CMV) atypical mycobacteria Nocardia asteroides aspergilli, candidae

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)

Etiology of pneumoniae V – revision Acute, nosocomial: VAP (ventilator-associated pneumonia) early (up to the 4th day of hospitalization): sensitive community strains of respiratory agents („gang of 4“) late (from the 5th day of hospitalization): resistant hospital strains Other nosocomial pneumoniae viruses (RSV, CMV) legionellae

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) - - -

Digestive system 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 (above all Bacteroides, Fusobacterium, Clostridium, Peptostreptococcus), only 1 % Enterobacteriaceae (mainly E. coli) & enterococci

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 consisting of 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 (by the toothbrush)

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 food sucrose Thrush (in Latin soor): coating of Candida albicans; in newborns & debilitated persons Herpetic stomatitis: primary infection with HSV 1 Ludwig´s angina: polymicrobial anaerobic infection of sublingual and submandibular spaces (Porphyromonas, Prevotella etc.)

Oesophagus Infections of oesophagus never occur in previously healthy individuals Oesophagitis can be seen only in severely immunocompromised persons (in AIDS or after a chemotherapy) Etiology: Candida albicans Cytomegalovirus (CMV)

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 hydrolyzing tissue urea it increases pH around itself (1 molecule of urea NH2-CO-NH2 + H2O → → 1 molecule of CO2 + 2 molecules of NH3) Helicobacter pylori causes: chronic gastritis peptic ulcers (Warren & Marshall, Nobel price in 2005)

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

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)

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 (dangerous for the fetus) Peritonitis (e.g. after appendicitis or an injury): colonic flora (Bacteroides fragilis + other anaerobes + mixture of facultative anaerobes) Viral hepatitis: HAV, HBV, HCV, HDV, HEV

Small and large intestine Bacterial overgrowth syndrome: After surgery, during depressed peristalsis or gastric achlorhydria the 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 (shigellae or amoebae)

Etiology of diarrheal disease Infectious etiology: Bacterial (most frequent) Viral Parasitic Mycotic Non-infectious etiology: Food poisoning . . . (to be continued in the next lecture)

Homework 2 – solution Leonardo da Vinci (1452-1519): Fetus in the Womb (between 1510-1512)

Successful homework solver: Homework 2 – solution Leonardo da Vinci (1452-1519): Fetus in the Womb (between 1510-1512) Successful homework solver: Sacheen Nathwani Congratulations!

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

Thank you for your attention Answer and questions The solution of the homework and possible questions please mail to the address mvotava@med.muni.cz Thank you for your attention