MICR J 210 1st Edition Lecture 15Outline of Last Lecture I. StreptococciII. Streptococcus pyogenesIII. Streptococcus agalactiaeIV. Viridans streptococcusV. Streptococcus pneumoniaeVI. ComplianceOutline of Current Lecture I. PneumoniaII. Streptococcus pneumoniaeIII. Legionella pneumophilaIV. Mycoplamsa pneumoniaeV. Chlamydia pneumoniaeVI. Klebsiella pneumoniaeCurrent Lecture- Pneumoniao Definition: inflammation of the lung alveoli resulting in accumulations of exudateand fluid in the lungo Host Defenses against pneumonia Mucus: - Traps microbes Ciliated epithelium- Sweeps mucus-trapped microbes towards pharynx out of sinuses and bronchi Epiglottal reflexThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Guard against aspiration (gag) Cough reflex- Expels bacteria-laden mucus from bronchioles Macrophages- Phagocytise microorganisms that reach the alveolio Alveolar macrophages (antigen presenting cells)  Lymphatic drainage- Flushes phagocytised microbes from bronchioleso Risk factors for pneumonia Anything which can damage the lung tissue puts individuals at risk for pneumonia- Viral infection or smoking which damage ciliated epithelium of upper airwayso Creates opportunity for opportunistic infection- Fluid accumulation in lungo Heart conditions (left-ventricle heart failure) and drugs cancause edema in the lungs- Decreased macrophage action. i.e: Influenza or smokingo Viral infection preoccupy the macrophages- Elderly, smokers (50x increase in risk), miners, influenza, sickle cell anemia (less effected gas exchange), immunosuppression, chronic cardiovascular disease (blood pressure isn’t high enough to get a good flow into the lungs)- Alcohol and drug (aspiration pneumonia)o If they pass out and faint and vomit at the same time they can aspirate their vomit and it ends up in the lungso Microbes that cause pneumonia Bacteria- Streptococcus pneumonia: gram + - Staphylococcus aureus: gram +- Legionella pneumophilae: gram -- Mycoplasma pneumoniae: gram -- Chlamydia pneumoniae: gram - - Klebsiella pneumoniae: gram - - Mycobacterium tuberculosis: acid fast positive  Viruses- Influenza Protozoa- Toxoplasma gondii Fungi- Pneumocystis jirovecii- Streptococcus pneumoniaeo Gram-positiveo Also termed “pneumococcus”o Ungroupable with Lancefield systemo Alpha hemolytic (aerobic)o Beta hemolytic (anaerobic)o Normal pharyngeal microbiota (throat) Part of normal florao Sensitive to optochino Virulence factors Presence of capsule Allows bacteria to evade immune cells Most important virulence factoro Protein adhesin Allows attachment to epithelial cells Swallowing will not wash them away- The back of the throat is their nicheo Secretory IgA protease Destroys IgA Enzymeo Pneumolysin Lyses cytoplamic membranes of epithelial cells Allows it to become hemolytic—can also be used to destroy red blood cellso Classification Taxonometric classification- S. pneumoniae Serological classifical (lancefield)- Nongroupable Hemolysis patterns- Alphao Sputum is needed for a culture Mucus coughed up from lower respiratory tract- Hard to get a good sputum sample bc it gets contaminated with saliva Often examined for infectious microbes Need to distinguish between sputum and saliva- Sputum has PMNs- Saliva has epithelial cells (from cheek lining) are much largero Gram stain of sputum Strep pnumoniaeappears as gram-positive cocci, often appearing in pairso Encapsulated S. pneumoniae Capsule is most important virulence factor UnencapsulatedS. pneumoniae are not virulent- Unencapsulated do not cause disease 90 variations of capsule exist- Antibodies against capsule polysaccharides can be used for serotypingo Serology Quellung reaction- An increase in the opacity and visibility of the capsule of encapsulated bacteria resulting from exposure to specific, agglutinating, anticapsular antibodieso Halo forms when antibodies mix with the Glycocalyx of thecapsuleo Effects on the lung 1. Congestion (1-2 days)- protein-rich edema fluid containing numerous organisms (Streptococcus pneumoniae) filling the alveoli. Marked congestion of the capillaries is typical.- Alveoli fill up with cells and bacteria  2. Red hepatization (2 nd -4 th day)- Massive outpouring of PMN accompanied by intra-alveolar hemorrhages. - Many of the red blood cells undergo lysis. These cells, together with PMN, produce the rusty sputum. o Hemoglobin from lyses red blood cells contaminates the alveoli and produces the rusty colored sputum- Because the firm consistency of the affected lung is similar to the liver, this stage has been named “red hepatization”.o The lower lobes (base) is the part that is typically affected  3. Gray hepatization (4 th -6 th day)- Involves the lysis of PMN and the appearance of macrophages, which phagocytose the fragmented PMN and other inflammatory debris. - The lung is now no longer congested but still remains firm in this stage.  4. Resolution (8 th -9 th day) :- The alveolar exudates are removed and the lung gradually returns to normal- Some lymphocytes are typically still present and still at work to remove bacteriao 2 ways to determine involvement of the lung Chest X-ray- Generally localized to lower lobes of lungs (termed lobar pneumonia)- Lung tissue will be more dense in an infected lung Rusty sputumo Other infections with S. pneumoniae Otitis media (middle ear infection)- Primarily a childhood disease; 80% of all kids get it by age 3- Passive smoke exposure, non-breast fed infants at higher risk Sinusitis: - Occurs in patients of all ages Bacteremia: (bacteria enters the bloodstream)- 85% fatality rate without Tx Meningitis - The leading cause of bacterial meningitis in all ages- 3,000 deaths/year in U.S.- Causes the highest post-infection, permanent neurological damageso Carriage Rate Common inhabitant of the throat and nasopharynx.  Found in ~30% of healthy individuals will carry the strain More common in children that adults More common in cold seasons Disease occurs when organism spreads to distal loci- Lungs (pneumonia) -500,000 cases annually - Paranasal sinuses (sinusitis) ~ 7 million cases annuallyo Chronic congestion- Middle ears (otitis media) ~7 million cases