بسم الله الرحمن الرحيم GENUS: BORDETELLA Prof. Khalifa Sifaw Ghenghesh

Small, Gram-negative coccobacilli Strict aerobes. X and V factors not required for growth Three species: – –B. pertussis, – –B. parapertussis – –B. bronchiseptica

Bordetella species

Bordetella bronchiseptica Leifson flagella stain

Scanning electron micrograph of Bordetella bronchiseptica

Bordetella pertussis Whooping Cough – –Paroxysmal coughing Require blood, or starch or charcoal for growth – –Bordet-Gengou medium (BGM) Strict aerobe Optimal temp. > o C

ANTIGENICITY 3 Major Agglutinogens >1, 2 and 3 Detected by using adsorbed, single-agglutinin sera 3 serotypes pathogenic to man – –Type 1,2 – –Type 1,3 – –Type 1,2,3 All 3 have a role in immunity

Virulence Factors Pertussis toxin (PT): an exotoxin which enters target cells and activates their production of cAMP, a molecule that acts as a second messenger in cell protein synthesis regulation Tracheal cytotoxin: causes ciliated epithelial cell destruction Hemoagglutinin: a cell surface protein which helps the bacterium bind to the host cell surface

PATHOGENESIS highly contagious bacterium Non-invasive disease Man > only natural host Incubation period >> 1-2 weeks Enters respiratory tract via inhalation > binds to and destroys the ciliated epithelial cells of the trachea and bronchi. Symptoms last for many weeks

LABORATORY DIAGNOSIS 1. Bacterial Culture: Specimen: – –Pernasal swab on flexible wire – –Specimens on several successive days> higher isolation rates. – –Transport media should not be used Culture: – –Immediately on BGM – –Incubate for at least 1 week Identification: – –Serological

2. Detection of Bacterial Antigens Bordetella antigens in serum and urine using specific antiserum Immunofluorescence Technique: – –Bacteria in nasopharyngeal secretions labelled with fluorescein- conjugated antiserum > examined with ultraviolet microscopy. 3. Detection of Bordetella Antibody: Sera and nasopharyngeal secretions examined for Ab > Agglutination Tests, ELISA

Bordetella pertussis

TREATMENT Erythromycin – –For 2 weeks – –May reduce the severity of illness if given before paroxysmal stage. – –No clinical effect when the infection is established – –May be given to protect non- vaccinated infants

CONTROL Vaccination: – –Safe and >90% effective. – –Adsorbed vaccine (i.e. with adjuvant). - -Contains all 3 agglutinogens. - -Minimum 3 doses. - -Minor adverse reactions: - - Erythema and local swelling, slight feverishness - - Possible neurological sequelae - Acellular pertussis vaccine

Bordetella parapertussis – –a respiratory pathogen that can cause mild pharyngitis. Bordetella bronchiseptica – –a cause of pneumonia, otitis media, and other respiratory infections in animals.