mycoplasma and legionella

Mycoplasma and Legionella Mycoplasma and Legionella

Ziad Elnasser, MD, Ph.DZiad Elnasser, MD, Ph.D

Mycoplasma and UreaplasmaMycoplasma 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 urealyticumUreaplasma urealyticum..

MicrobiologyMicrobiology

0.2 – 0.3 0.2 – 0.3 μμ pleomorphic, filamentous. pleomorphic, filamentous.No cell wall, triple membrane contains No cell wall, triple membrane contains

sterols from tissue.sterols from tissue.No stains, small genome.No stains, small genome.Aerobic to facultative anaerobe, grows on Aerobic to facultative anaerobe, grows on

MycoplasmaMycoplasma agar, inverted fried egg. agar, inverted fried egg.Binds to RBC’s on agar (Hemadsorption).Binds to RBC’s on agar (Hemadsorption).

Mycoplasma pneumoniaeMycoplasma 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 Droplets, low infectious dose, temperate

climates, 5-15y of age.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%.

PathogenesisPathogenesis

Trachea, bronchi, bronchioles and alveoli.Trachea, bronchi, bronchioles and alveoli.Cytadhesin (P1) binds to oligosaccharides Cytadhesin (P1) binds to oligosaccharides

containing sialic acid.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 Shedding 2-8 days before symptoms to 14

weeks after infection.weeks after infection.

Immunity 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 Cold agglutinins IgM binds to I Ag on

surface of RBC’s in 66% of cases.surface of RBC’s in 66% of cases.Reinfection could occur.Reinfection could occur.Symptoms related to immune response, Symptoms related to immune response,

more severe in adults.more severe in adults.Raynaud’s phenomena.Raynaud’s phenomena.

Clinical AspectClinical Aspect

Mild tracheobronchitis, fever, cough, Mild tracheobronchitis, fever, cough, headache and malaise.headache and malaise.

Less severe pneumonia (walking Less severe pneumonia (walking pneumonia).pneumonia).

X-ray shows patchy pneumonia, lower X-ray shows patchy pneumonia, lower lobe.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.

DiagnosisDiagnosis

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 Isolation in special media, incubation for

one week or longer.one week or longer.Serology 4 fold increase in titre.Serology 4 fold increase in titre.Cold agglutinins not specific, adenovirus, Cold agglutinins not specific, adenovirus,

Epstien barr virus.Epstien barr virus. Immune assays, DNA hybridization, PCR.Immune assays, DNA hybridization, PCR.

TreatmentTreatment

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

LegionellaLegionella

Gram negative bacilli, American legion Gram negative bacilli, American legion convention.convention.

Environmental pathogen.Environmental pathogen.Thin 0.5-0.7Thin 0.5-0.7μμm, filamentous 20m, filamentous 20μμ long. long.

Poor staining with gram but silver Poor staining with gram but silver impregnation is used (Dieterle).impregnation is used (Dieterle).

3 flagella, motile, non spore former.3 flagella, motile, non spore former.Outer membrane LPS but less compared Outer membrane LPS but less compared

to other g- bacteria.to other g- bacteria.

Growth and ClassificationGrowth and Classification

L-cysteine, ferric ions, acidic pH.L-cysteine, ferric ions, acidic pH.2-5 days needed for growth,ground glass 2-5 days needed for growth,ground glass

colonies.colonies.Catalase, oxidase, Catalase, oxidase, ββ lactamase. lactamase.14 serogroups, L.bozemanii, L.dumoffii, 14 serogroups, L.bozemanii, L.dumoffii,

L.micdadei.L.micdadei.Non infects humans.Non infects humans.

LegionellosisLegionellosis

Inhalation, destructive pneumonia.Inhalation, destructive pneumonia.1976 American Legion convention.1976 American Legion convention.Other stored sera proved of previous Other stored sera proved of previous

pneumonia caused by Legionella.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.

pathogenesispathogenesis

Necrotizing multifocal pneumonia.Necrotizing multifocal pneumonia. Alveoli and terminal bronchioles.Alveoli and terminal bronchioles. Inflamatory exudate contains fibrin, PMNs, Inflamatory exudate contains fibrin, PMNs,

macrophages, and erythrocytes.macrophages, and erythrocytes. Facultative intracellular pathogen→alveoli Facultative intracellular pathogen→alveoli

→alveolar macrophages→OMP binds C3 →alveolar macrophages→OMP binds C3 facilitates phagocytosis→Macrophage invasion facilitates phagocytosis→Macrophage invasion potentiator OMP→cell entry→coiling potentiator OMP→cell entry→coiling phagocytosis→apoptosis and pore forming phagocytosis→apoptosis and pore forming toxin.toxin.

Immunity 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 aspectsClinical aspects

Toxic pneumonia, myalgia, headache, Toxic pneumonia, myalgia, headache, fever, dry cough.fever, dry cough.

Chills, delirium, pleuritic chest pain, Chills, delirium, pleuritic chest pain, vomiting diarrhea.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.

DiagnosisDiagnosis

DFA.DFA.Culture of infected tissues.Culture of infected tissues.Lung aspirates, bronchoalveolar lavage, Lung aspirates, bronchoalveolar lavage,

lung biobsy.lung biobsy.Buffered Charcol Yeast Extract (BCYE).Buffered Charcol Yeast Extract (BCYE).PCR.PCR.Ag detection.Ag detection.

Treatment 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 systemsSilver and cupper ionization systemsMists of water.Mists of water.

PseudomonasPseudomonas

Gram negative bacillus.Gram negative bacillus.Colonizers and contaminants, Colonizers and contaminants,

apportunistic diseases.apportunistic diseases.Bacteremia, arthritis, abscesses, wounds, Bacteremia, arthritis, abscesses, wounds,

conjunctivitis, UTI.conjunctivitis, UTI.

Ps. aerugenosaPs. 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 Lps , pili, polar flagellum, alginate

(mannoronic and glucoronic acid) CF pts.(mannoronic and glucoronic acid) CF pts.

Extracellular productsExtracellular products

Exotoxin A ( lecithinase, hemolysis, Exotoxin A ( lecithinase, hemolysis, collagenase).collagenase).

ADP-ribosylation of EF-2.ADP-ribosylation of EF-2.Exoenzyme S ADP-ribosylates vimentin Exoenzyme S ADP-ribosylates vimentin

acts as adhesin.acts as adhesin.Elastases.Elastases.

DiseasesDiseases

Environment, throat, stool, > in hospitals.Environment, throat, stool, > in hospitals.Leukemia, Cystic fibrosis, and burns.Leukemia, Cystic fibrosis, and burns.Humidifiers, inhalators, contact lenses Humidifiers, inhalators, contact lenses

sloutions, medications, disinfectans, sinks.sloutions, medications, disinfectans, sinks.Food and water no problem.Food and water no problem.CF chloride ion transport defect, thick CF chloride ion transport defect, thick

mucus. mucus.

pathogenesispathogenesis

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 CS pts cells are less sialated increases

receptors for the organism.receptors for the organism. Biofilm (glycocalyx), alginate over produced.Biofilm (glycocalyx), alginate over produced. Interfers with antibiotics and Immune Interfers with antibiotics and Immune

mechanisms.mechanisms. CMI deficient patients.CMI deficient patients.

Clinical aspectsClinical 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 Treatment

Most resistant to penicillin, ampicillin, Most resistant to penicillin, ampicillin, cephalothin, tetracyclin, streptomycin, cephalothin, tetracyclin, streptomycin, chloramphenicol, sulfonamide.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 Burkholderia, Acinetobacter, aeromonas and

pleisomonas.pleisomonas.