Bordetella Bacteria and Whooping Cough

Bordetella

• Small, Gram-negative, aerobic, encapsulated coccobacilli
• Most important species: Bordetella pertussis
• Virulence factors:
  • Attachment factors: Filamentous hemagglutinin (FHA), Pertussis toxin (PTx)
  • Factors mediating tissue damage: PTx, Adenylate cyclase toxin, Tracheal cytotoxin, Endotoxin
• Causes whooping cough
• Culture characteristics:
  • Enriched medium (blood)
  • Bordet-Gengou agar (blood agar + growth factor)
  • Charcoal blood agar
  • Slow grower (6-7 days at 37°C)
  • Colonies characterized by mercury droplets appearance

Whooping Cough

• Incubation period: 1-2 weeks
• Acute respiratory disease (mainly affects children)
• Transmitted via inhalation of droplets
• Non-invasive organism
• Stages:
  • Catarrhal stage (1-2 weeks): attachment and adhesion, virulence factors: FHA, PTx
  • Paroxysmal stage (3 weeks): tissue damage, virulence factors: PTx, Adenylate cyclase toxin, Tracheal cytotoxin, Endotoxin
  • Convalescent stage (3 weeks): slow recovery, no organism

Diagnosis

• Can be diagnosed clinically
• Specimens: Nasopharyngeal secretion swab, Aspiration of Nasopharyngeal secretion, Cough plate
• Direct detection: Direct Fluorescent Assay (DFA), Polymerase Chain Reaction (PCR)
• Culture: Bordet-Gengou agar, Charcoal agar
• Identification: Oxidase +ve, Catalase +ve, Morphology: mercury droplets appearance

Treatment and Prevention

• Treatment: Erythromycin
• Prevention: Whooping cough vaccine (killed whole cell vaccine, part of DPT vaccine), Acellular vaccine (genetically inactivated PTx) (DTaP)
• Chemoprophylaxis: Erythromycin

Brucella

• Named after David Bruce (1855-1931)
• Characteristics: Short, Gram-negative, aerobic, non-motile, non-capsulated, facultative intracellular pathogen
• Zoonotic disease: primary infection in animals
• Members of the genus: Brucella abortus, Brucella melitensis, Brucella suis

Brucellosis

• Undulant fever or malt fever
• Zoonotic
• Mode of transmission: ingestion of animal secretion, direct contact with infected animal, inhalation of animal secretion
• Pathogenesis: Endotoxin is the major virulence factor
• Clinical manifestation: Fever, chill, sweating, headache, malaise, weakness, undulant fever, body ache, enlarged lymph nodes, liver, spleen, osteomyelitis, meningitis
• Lab diagnosis:
  • Specimens: blood, bone marrow (invasive), other samples (according to site of infection)
  • Direct detection and cultivation (dangerous)
  • Serology: Standard tube agglutination test, ELISA, Brucellin Test

Treatment and Prevention

• Combination therapy for long time: Doxycycline & Rifampicin
• Prevention: Control of infected animal, Live attenuated vaccine for cattle, Pasteurization of milk

This quiz covers the characteristics and virulence factors of Bordetella bacteria, specifically Bordetella pertussis, which causes whooping cough. It also includes information on culture characteristics and growth requirements.