Mycoplasma and Legionella Ziad Elnasser, MD, Ph.D

Mycoplasma and Ureaplasma No cell wall. No cell wall. The smallest of free living organisms. The smallest of free living organisms. Associated with human disease: Associated with human disease: Mycoplasma pneumoniae. Mycoplasma pneumoniae. Mycoplasma hominis. Mycoplasma hominis. Ureaplasma urealyticum. Ureaplasma urealyticum.

Microbiology 0.2 – 0.3 μ pleomorphic, filamentous. 0.2 – 0.3 μ pleomorphic, filamentous. No cell wall, triple membrane contains sterols from tissue. No cell wall, triple membrane contains sterols from tissue. No stains, small genome. No stains, small genome. Aerobic to facultative anaerobe, grows on Mycoplasma agar, inverted fried egg. Aerobic to facultative anaerobe, grows on Mycoplasma agar, inverted fried egg. Binds to RBC’s on agar (Hemadsorption). Binds to RBC’s on agar (Hemadsorption).

Mycoplasma pneumoniae Pneumonia in young, any season. Pneumonia in young, any season. Atypical pneumonia, scattered patches. Atypical pneumonia, scattered patches. 10% of all Pneumonias. 10% of all Pneumonias. Droplets, low infectious dose, temperate climates, 5-15y of age. Droplets, low infectious dose, temperate climates, 5-15y of age. Sporadic endemic illness in families. Sporadic endemic illness in families. IP 2-15 days, infectivity 60%. IP 2-15 days, infectivity 60%.

Pathogenesis Trachea, bronchi, bronchioles and alveoli. Trachea, bronchi, bronchioles and alveoli. Cytadhesin (P1) binds to oligosaccharides containing sialic acid. Cytadhesin (P1) binds to oligosaccharides containing sialic acid. I Ag on surface of RBC’s. I Ag on surface of RBC’s. Destroys cillia and causes desquamation. Destroys cillia and causes desquamation. Shedding 2-8 days before symptoms to 14 weeks after infection. Shedding 2-8 days before symptoms to 14 weeks after infection.

Immunity Local and systemic. Local and systemic. CF antibodies, IgA antibodies 2-4 weeks. CF antibodies, IgA antibodies 2-4 weeks. Cold agglutinins IgM binds to I Ag on surface of RBC’s in 66% of cases. Cold agglutinins IgM binds to I Ag on surface of RBC’s in 66% of cases. Reinfection could occur. Reinfection could occur. Symptoms related to immune response, more severe in adults. Symptoms related to immune response, more severe in adults. Raynaud’s phenomena. Raynaud’s phenomena.

Clinical Aspect Mild tracheobronchitis, fever, cough, headache and malaise. Mild tracheobronchitis, fever, cough, headache and malaise. Less severe pneumonia (walking pneumonia). Less severe pneumonia (walking pneumonia). X-ray shows patchy pneumonia, lower lobe. X-ray shows patchy pneumonia, lower lobe. Pleural effusion in 25% Pleural effusion in 25% Pharyngitis with fever, sore throat. Pharyngitis with fever, sore throat. Otitis media, myringitis, and pneumonia. Otitis media, myringitis, and pneumonia.

Diagnosis Clinically overlaps with viral and bacterial. Clinically overlaps with viral and bacterial. PMN’s in gram stain, bacteria not seen. PMN’s in gram stain, bacteria not seen. Isolation in special media, incubation for one week or longer. Isolation in special media, incubation for one week or longer. Serology 4 fold increase in titre. Serology 4 fold increase in titre. Cold agglutinins not specific, adenovirus, Epstien barr virus. Cold agglutinins not specific, adenovirus, Epstien barr virus. Immune assays, DNA hybridization, PCR. Immune assays, DNA hybridization, PCR.

Treatment Erythromycin, Tetracycline. Erythromycin, Tetracycline. Clarthromycin, Azithromycin. Clarthromycin, Azithromycin. Flouroquinilone. Flouroquinilone.

Legionella Gram negative bacilli, American legion convention. Gram negative bacilli, American legion convention. Environmental pathogen. Environmental pathogen. Thin μm, filamentous 20μ long. Poor staining with gram but silver impregnation is used (Dieterle). Thin μm, filamentous 20μ long. Poor staining with gram but silver impregnation is used (Dieterle). 3 flagella, motile, non spore former. 3 flagella, motile, non spore former. Outer membrane LPS but less compared to other g- bacteria. Outer membrane LPS but less compared to other g- bacteria.

Growth and Classification L-cysteine, ferric ions, acidic pH. L-cysteine, ferric ions, acidic pH. 2-5 days needed for growth,ground glass colonies. 2-5 days needed for growth,ground glass colonies. Catalase, oxidase, β lactamase. Catalase, oxidase, β lactamase. 14 serogroups, L.bozemanii, L.dumoffii, L.micdadei. 14 serogroups, L.bozemanii, L.dumoffii, L.micdadei. Non infects humans. Non infects humans.

Legionellosis Inhalation, destructive pneumonia. Inhalation, destructive pneumonia American Legion convention American Legion convention. Other stored sera proved of previous pneumonia caused by Legionella. Other stored sera proved of previous pneumonia caused by Legionella. Water reservoirs of large buildings. Water reservoirs of large buildings. No person to person transmission. No person to person transmission. Not present in healthy people. Not present in healthy people. Low virulence to humans. Low virulence to humans.

pathogenesis Necrotizing multifocal pneumonia. Necrotizing multifocal pneumonia. Alveoli and terminal bronchioles. Alveoli and terminal bronchioles. Inflamatory exudate contains fibrin, PMNs, macrophages, and erythrocytes. Inflamatory exudate contains fibrin, PMNs, macrophages, and erythrocytes. Facultative intracellular pathogen→alveoli →alveolar macrophages→OMP binds C3 facilitates phagocytosis→Macrophage invasion potentiator OMP→cell entry→coiling phagocytosis→apoptosis and pore forming toxin. Facultative intracellular pathogen→alveoli →alveolar macrophages→OMP binds C3 facilitates phagocytosis→Macrophage invasion potentiator OMP→cell entry→coiling phagocytosis→apoptosis and pore forming toxin.

Immunity Virulence because it is intracellular. Virulence because it is intracellular. CMI is the key. CMI is the key. Inhibition of MHC antigens. Inhibition of MHC antigens. Humoral immunity is less important. Humoral immunity is less important. Antibodies only enhancing phagocytosis. Antibodies only enhancing phagocytosis.

Clinical aspects Toxic pneumonia, myalgia, headache, fever, dry cough. Toxic pneumonia, myalgia, headache, fever, dry cough. Chills, delirium, pleuritic chest pain, vomiting diarrhea. Chills, delirium, pleuritic chest pain, vomiting diarrhea. Patchy infiltrates in chest x-ray. Patchy infiltrates in chest x-ray. Hepatic dysfunction. Hepatic dysfunction. Mortality is about 15%. Mortality is about 15%. Pontiac fever. Pontiac fever.

Diagnosis DFA. DFA. Culture of infected tissues. Culture of infected tissues. Lung aspirates, bronchoalveolar lavage, lung biobsy. Lung aspirates, bronchoalveolar lavage, lung biobsy. Buffered Charcol Yeast Extract (BCYE). Buffered Charcol Yeast Extract (BCYE). PCR. PCR. Ag detection. Ag detection.

Treatment Erythromycin. Erythromycin. Most legionella produces beta lactamases. Most legionella produces beta lactamases. Tetracycline, rifampin, newer quinolones. Tetracycline, rifampin, newer quinolones. Azithromycin, clarithromycin. Azithromycin, clarithromycin. Prevention:Hyperchlorination of water. Prevention:Hyperchlorination of water. Heating water to more than 70C. Heating water to more than 70C. Silver and cupper ionization systems Silver and cupper ionization systems Mists of water. Mists of water.

Pseudomonas Gram negative bacillus. Gram negative bacillus. Colonizers and contaminants, apportunistic diseases. Colonizers and contaminants, apportunistic diseases. Bacteremia, arthritis, abscesses, wounds, conjunctivitis, UTI. Bacteremia, arthritis, abscesses, wounds, conjunctivitis, UTI.

Ps. aerugenosa Aerobic motile, g- rod, pale staining. Aerobic motile, g- rod, pale staining. Colourfull water soluble pigments. Colourfull water soluble pigments. The most resistant to antimicrobial agents. The most resistant to antimicrobial agents. Simple growth requirements. Simple growth requirements. 20 – 40 C, Oxidase +, fruity odor. 20 – 40 C, Oxidase +, fruity odor. Pyocyanin, Flourescin. Pyocyanin, Flourescin. Lps, pili, polar flagellum, alginate (mannoronic and glucoronic acid) CF pts. Lps, pili, polar flagellum, alginate (mannoronic and glucoronic acid) CF pts.

Extracellular products Exotoxin A ( lecithinase, hemolysis, collagenase). Exotoxin A ( lecithinase, hemolysis, collagenase). ADP-ribosylation of EF-2. ADP-ribosylation of EF-2. Exoenzyme S ADP-ribosylates vimentin acts as adhesin. Exoenzyme S ADP-ribosylates vimentin acts as adhesin. Elastases. Elastases.

Diseases Environment, throat, stool, > in hospitals. Environment, throat, stool, > in hospitals. Leukemia, Cystic fibrosis, and burns. Leukemia, Cystic fibrosis, and burns. Humidifiers, inhalators, contact lenses sloutions, medications, disinfectans, sinks. Humidifiers, inhalators, contact lenses sloutions, medications, disinfectans, sinks. Food and water no problem. Food and water no problem. CF chloride ion transport defect, thick mucus. CF chloride ion transport defect, thick mucus.

pathogenesis Attachment favored by loss of fibronectin. Attachment favored by loss of fibronectin. Exotoxin A, exotoxin S, and elastin. Exotoxin A, exotoxin S, and elastin. Hemorragic destruction of blood vessles. Hemorragic destruction of blood vessles. CS pts cells are less sialated increases receptors for the organism. CS pts cells are less sialated increases receptors for the organism. Biofilm (glycocalyx), alginate over produced. Biofilm (glycocalyx), alginate over produced. Interfers with antibiotics and Immune mechanisms. Interfers with antibiotics and Immune mechanisms. CMI deficient patients. CMI deficient patients.

Clinical aspects Apportunists. Apportunists. pnemonia and in CF is chronic. pnemonia and in CF is chronic. Otitis externa, swimmers ear, in DM. Otitis externa, swimmers ear, in DM. Ecthyma gangrenosum. Ecthyma gangrenosum. Diagnosis is simple. Diagnosis is simple.

Treatment Most resistant to penicillin, ampicillin, cephalothin, tetracyclin, streptomycin, chloramphenicol, sulfonamide. Most resistant to penicillin, ampicillin, cephalothin, tetracyclin, streptomycin, chloramphenicol, sulfonamide. New aminoglycosides. New aminoglycosides. Third and fourth generation cephalosporins. Third and fourth generation cephalosporins. Carbapenems and flouroquinolones. Carbapenems and flouroquinolones. CF aerosolized tobramycin. CF aerosolized tobramycin. Vaccines tried in CF some improvement. Vaccines tried in CF some improvement. Burkholderia, Acinetobacter, aeromonas and pleisomonas. Burkholderia, Acinetobacter, aeromonas and pleisomonas.