BORDETELLA SPECIES

(Bordetella species) Mode of transmission,mechanisms by which microorganisms cause disease and diagnosis

 Define Bordetella  

A Gram negative coccobacili

List the species of medical importance 

• Bordetella pertussis
• Bordetella parapertussis
• Bordetella bronchiseptica

Mention the species of medical importance

• Bordetella pertussis

Describe the normal habitat

• Pseudomonas species can be found in water, soil sewage and vegetation. They can also be found in the intestinal tract.
• Pseudomonas aeruginosa is frequently present in hospital environments especially in moist places such as sinks, bowls, drains, cleaning buckets and humidifiers. It can also be found growing in eye drops, ointments and weak antiseptic solutions
• Pseudomonas pseudomalleiis naturally found in rice paddy fields, the mud of riverbanks and surface stagnant water. The organism can infect cattle, pigs and other animals.

Describe the morphology Pseudomonas aeruginosa

·         .Bordetella pertussis is a small non- motile, capsulated Gram negative coccobacillus. It may occur singly or in chains and may show bipolar staining.

·         Bordetella parapertussis is a non- motile gram-negative rod.

·         Bordetella brochiseptica is similar to Bordetella pertussis but is motile

Describe the mode of transmission and pathogenicity of Pseudomonas aeruginosa 

TRANSMISSION

·         By inhalation droplets from infected person.

PATHOGENICITY-

·         Bordetella pertussis causes whooping cough an infection of the mucosa of the upper respiratory tract. Toxin from the organisms causes the secretion; of mucus which leads to irritation and the spasms of coughing associated with the disease. There is a marked Leucocytosis with an absolute Lymphocytosis.

·         Complications of infection include lung damage with emphysema, secondary infection leading to bronchopneumonia, bronchiectasis, convulsions and occasionally brain damage.

·         Bordetella parartussis causes a milder form of whooping cough.

• Bordetella bronchiseptica is mainly animal pathogen. It may however cause a whooping cough like illness in humans and occasionally infection of wounds.

 Describe the laboratory diagnosis Salmonella 

1.SPECIMENS

·         Nasopharyngal secretions are required.

·         These are collected using a pernasal swab or by aspiration

2.CULTURE CHARACTERISTICS

·         Bordetella species are strict aerobes. Specimen for the isolation of Bordetella pertussis must be cultured as soon as possible after they are collected.

·         As selective and enrichment medium such as charcoal cephalexin blood agar (CCBA) or Bordet – Gengou penicillin medium is required for the primary isolation of Bordetella pertussis. Blood agar can be used for subculturing the organism.

·         When incubated for 2 – 6 days at 35 – 37⁰c in a most aerobic atmosphere Bordetella pertussis produces small, raised shiny (mercury – like) colonies on CCBA or Bordet – Gengou medium. The colonise are usually mucoid

·         Bordetella parapertussis grows more rapidly and forms larger colonies than Bordetella pertussis. It produces a pigment in the medium and is able to grow aerobically on blood agar and nutrient agar.

·         Bordetella bronchiseptica grows well on blood agar and nutrient agar. On blood agar, it produces glistening beta- haemolytic colonies, usually after 24 – 48 hours incubation at 35 – 37⁰c

3.BIOCHEMICAL TESTS

.

Species	Motility	Urea	Oxidase test	Catalase
Bordetella pertussis	-	-	+	+
Bordetella parapertussis	-	+ After 24 hrs	-	+
Bordetella bronchiseptica	+	+ After 4 hrs	+	+

All three species ferment glucose and lactose with acid production.

4.PREVENTION AND CONTROL

·         By giving prophylactic vaccination. Erythromycin can be given to contacts.

·         Treatment of infected persons.