Legionella pneumophila, Haemophilus, Bordatella Flashcards
(22 cards)
Bordetella Genus species
4 responsible for Human diseases
- B. Pertussis: whooping cough
- B. Parapertussis: milder cough
- B. Bronchiseptica (resp. disease)
- B. Holmesii (sepsis)
B. Pertussis Info
- Spread by Respiratory Droplets
- Mostly in non-vaccinated pop.
B. Pertussis Morphology
- Gram Negative
- Coccobacilli
- Bordet-Gengou Agar used (blood + penicillin)
B. Pertussis Non-Toxic Virulence Factors
- Fibriae
- Filamentous Haemagglutinin (damages cilia)
- Outer Mem. P (OMP) for adhesion
- Pertactin
B. Pertussis Toxic Virulence Factors
- Endotoxin (LPS)
- Pertussis Toxin: A/B, ADP ribosylation binds Gi, cAMP accumulation
- Adenylate cyclase Toxin: cAMP increase, lots of lung secretions
- Tracheal Cytotoxin: Damages Cilia
- Dermonecrotic Toxin: Causes necrosis
B. Pertussis Diseases
Whooping cough = Pertussis
(7-10 day incubation)
1) Catarrhal stage: 1-2 weeks, viral resp. infection symptoms, cough, runny/stuffy nose, congestion
2) Paroxysmal stage: 2-3 weeks, impaired mucous clearance, paroxysmal cough (whoop), conjunctival hemorrhage maybe
3) Convalescent Stage: Cough improves over weeks to months (100 day cough)
B. Pertussis Treatment
- Macrolides (azithromycin)
- DTaP vaccine (acellular): inactive toxin, inactive fil.haemag, inactive pertactin antigen
B. Pertussis Microbiological Diagnosis
Bordet-Gengou Agar
- Sputum sample
- IgM, IgA, IgG serology
- PCR
Haemophilus genus species
- H. Influenzae (upper resp.)
- H. Ducreyi (STI)
- H. Aegyptius (nasopharynx)
- H. Parainfluenzae (normal mouth flora)
Haemophilus Morphology
- Gram Negative
- Coccobacilli
- Blood-loving bacteria
Haemophilus Cultivation & where does it grow
- Chocolate Agar + CO2 enrichment
- Requires Hemin (FX), NAD (FV) for growth
- Translucent colonies in 24-72h
- On blood agar grows on hemolytic zones of other bacteria
Haemophilus Virulence Factors (inf, ducreyi, aegypticus)
- H. Influenzae: Polysaccharide Capsule (A-F), B is important, IgA protease, Endotoxin (LPS)
- H. Ducreyi: Cytotoxin, Ashesins, Endotoxin (LOS)
- H. Aegypticus: Polysaccharide capsule, IgA protease, Ashesins, Endotoxin (LPS)
H. Influenzae Diseases
- Otitis Media
- Sinusitis
- Pneumonia
- Meningitis
- Epiglottitis
- Cellulitis
H. Ducreyi, Aegypticus, Parainfluenzae Diseases
- H. Ducreyi: Chancroid/Ulculs Molle (STI) genital ulcer (X)
- H. Aegypticus: Conjunctivitis & Brazilian purpuric fever
- H. Parainfluenzae: Endocarditis in immunocomp (V)
Haemophilus Treatment
- Ceftriaxone (invasive)
- Augmentin (clavulanic + amox) in non-invasive
- Hib Vaccine (B-serotype) obligatory
Legionella genus Info
- Generally in fresh water unicellular organisms or amoebae
- Presence can usually be detected in drinking/tap water
- Only dangerous when water is >25˚C
L. Pneumophilia info
- Spread from Water
- Transmitted by Aerosol or vaporized water
- No human to human spread
- Facultative I.C
- Oxidase +
L. Pneumophilia Morphology
- Gram Negative
- Coccobacilli
- Fastidious
- Require L-cysteine & Iron on Buffered Charcoal Yeast Agar (BCYE)
L. Pneumophilia Virulence Factors
- Proteases for invation
- Phospholipases for cell lysis
- Biofilm formation
- LPS
L. Pneumophilia Diseases
- Pontiac Fever (legionellosis): flu-like, headache, fever, malaise
- Legionnaire’s Disease: Atypical Pneumonia, Dry cough, fever, headache, confusion, Hyponatremia
L. Pneumophilia Treatment
- Macrolides
- Fluoroquinolones
- Rifampicin
L. Pneumophilia Microbiological Diagnosis
- Urine Antigen rapid test
- Blood serology
- BCYE agar (buffered Charc.)
- Lung biopsy or X-ray
(no sputum)
