Bordetella pertussis

University of Wisconsin - La Crosse

Bordetella pertussis (B. Pertussis) is a small, coccobacillus. Coccobacillus are rod-shaped bacteria. Cocco comes from "cocci" meaning spherical shaped and bacillus comes from "bacilli" meaning elongated. B. pertussis, like most pathogenic bacteria, is Gram-negative. Gram-negative bacteria contain a lipopolysaccharide (LPS) layer. The LPS triggers the body's immune response. The immune system senses a cytokine reaction, which is toxic to the body. Because of this, the body initiates the inflammation of the tissues and blood vessels. B. pertussis is non-motile, meaning it doesn't move.

Classification

Domain: Prokaryotes
Kingdom:Bacteria
Phylum: Proteobacteria
Class:Betaproteobacteria
Order:Burkholderiaceae
Family:Alcaligenaceae
Genus: Bordetella
Species: B. pertussis

Centers for Disease Control (CDC) and Prevention

There are currently eight species in the Bordetella genus. Three species in this genus are known to be pathogenic to humans. B. pertussis and B. parapertussis are very similar species. Both species cause pertussis (whooping cough) in humans and are separated merely by the toxins they release during infection. B. parapertussis releases toxins that seem to cause a milder form of pertussis (whooping cough). B. bronchiseptica causes respiratory disease in various mammals and occasionally in humans. The species is further separated from B. pertussis and B. parapertussis by being motile. The human pathology of the remaining five species is relatively unknown. B. avium and B. hinzii, are known to cause respiratory disease in poultry.

Habitat

B. pertussis colonize the cilia of the mammalian respiratory epithelium. The epithelium is a tissue composed of a layer of cells. The main purpose of the respiratory epithelium is to moisten and protect the airways. It was originally thought that B. pertussis did not invade the tissues. Though, recent research has shown that tissue invasion may occur. After B. pertussis has invaded the respiratory tract, the bacteria use several toxins to bind and destroy the epithelial cells. It begins by using hemoagglutinin, a protein, which aids the bacteria in binding to the cilia surface. Next, the pertussis toxin, an exotoxin, enters the cells and activates the production of cAMP. This molecule is one of the messengers in cell protein synthesis regulation. Finally, B. pertussis releases the tracheal cytotoxin, which causes the destruction of the cilia in the epithelial cells.

Pertussis (Whooping Cough)

Pertussis, or whooping cough, is a highly contagious respiratory tract infection. It affects an estimated 39 million people each year, and kills 297,000 people worldwide.

Areas of infection
	- Mouth - Nose - Throat

Risk groups
	- Unvaccinated children (especially infants) - Adolescents whose immunity has waned - Adults whose immunity has waned

Transmission
	- Direct contact with droplets from coughing or sneezing by an infected person - Can continue to transmit the bacteria three weeks after coughing spells have stopped - Can be carried by individuals who are immune and transmitted to those who are not - Usual epidemic cycles in most countries is every two to five years

Symptoms
	- Incubation period is five to ten days - Infected person usually first shows cold symptoms (i.e. runny nose, sneezing, fever, and mild cough) - The cough worsens and comes in bursts - At the end of the cough, the infected person takes in air with a high-pitched "whoop" from which the infection gets its name

Complications
	- Can cause death in infants - Convulsions - Dehydration - Inflammation of the middle ear - Lost of appetite - Seizures

Treatment
	- Antibiotic treatment, usually erythromycin - Increased fluids - Increased rest

Prevention
	- Immunization with pertussis vaccine

References

- Atkinson W, Hamborsky J, McIntyre L, Wolfe S, eds. (2007). Epidemiology and prevention of vaccine preventable disease. (10th Ed., pp. #81-100). Atlanta, Georgia: Center for Disease

- Centers for Disease Control (CDC) and Prevention; Department of Health and Human Services. Pertussis. http://www.cdc.gov/ncidod/dbmd/diseaseinfo/pertussis_t.htm

- Cherry, J.D. (1999). Epidemiological, clinical, and laboratory aspects of pertussis in adults. Clinical Infectious Disease, 28, S112-117.

- Farizo, K. M., Cochi, S. L., Zell, E. R. et al. (1992). Epidemiological features of pertussis in the United States. Clinical Infectious Diseases, 14, 708-719.

- Frits R. Mooi, Inge H. M. van Loo, and Audrey King. National Institute for Public Health and the Environment (RIVM) Bilthoven, The Netherlands. http://www.cdc.gov/ncidod/eid/vol7no3_supp/images/mooi1b.gif

- Ivanoff, B., Robertson, S. E. (1997). Pertussis: A worldwide problem. Dev Biol Stand, 89, 3-13.

- Kendrick, P. L. (1975). Can whooping cough be eradicated? Journal of Infectious Diseases,132,707-712.

- World Health Organization (WHO). Pertussis - the disease. http://www.who.int/immunization/topics/pertussis/en/index1.html

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