A Bordering Cough

A Case Study about Bordetella persussis

by Janell Jones

Patient History

A 6 year old boy with a persistent cough for 2 weeks

During the last 2 days he experienced vomiting after severe coughing episodes

Laboratory Findings

Gram stain of sputum revealed small gram negative bacilli

No growth on routine blood agar

After 5 days, growth was recovered on Regan-Lowe agar

Gram Stain photo www.vaccineinformation.org/photos/pertcdc001a.jpg

Courtesy of Centers for Disease Control and Prevention

Diagnosis

Bordetella pertussis

AKA

Whooping Cough

Bordetella pertussis

B. pertussis produces disease only in humans

Pertussis is a highly contagious, acute infection of the upper respiratory tract

Infection is transmitted from person to person by direct contact or airborne droplets

Prior to mass immunization, an estimated 95 percent of people contracted Pertussis during their life time

Symptoms

Initially, symptoms resemble those of a common cold (sneezing, runny nose, mild cough)

Within two weeks, the cough becomes more sever and violent, coughing associated with vomiting and a characteristic intake of breathe that sounds like a “whoop”.

Between these attacks of coughing the individuals appears and feels perfectly well

Whooping cough lasts at least 3 weeks and can go on for 3 months or even longer

Listen to a pertussis cough at this web site

http://www.immunizationed.org/pertus.asp

Complications

Middle ear infections Dehydration Pneumonia Convulsions (seizures) Brain damage from lack of oxygen Brief episodes of stopped breathing

Pathogenesis

The bacteria enter the mouth or nasopharynx as aerosols

The bacteria binds to ciliated cells in the respiratory mucosa

B. pertussis produces a number of adhesins which aid in its ability to colonize

B. pertussis produces only localized infections Pertussis causes about 300,000 deaths/year in

un-immunized populations in the world

Who is at risk?

Newborns until they have had their primary whooping cough shots

Children who have not been immunized People over 10 years old but more likely over

50 whose immunization is wearing off The over 50’s who never had the chance of

immunization but never got the natural infection as children

Cultivation

B. pertussis is fastidious (it doesn’t grow on typical blood agar)

Growth after 3-5 days at 35oC in a humidified atmosphere without elevated carbon dioxide on Regan-Lowe medium

Regan-Lower is a charcoal agar with 10% horse blood and cephalexin antibiotic

It appears as small, smooth shiny colonies with a pearl-like luster resembling mercury droplets surrounded by a zone of hemolysis

Laboratory Identification

Faintly-staining small gram-negative bacilli on Gram stain

A strict aerobe that is nonfermentative and nonmotile

Catalse and Oxidase positive Nitrate, Citrate and Urease negative Specimens are sent to the state health

department for confirmation

Treatment

For the average case of whooping cough, there is no treatment likely to make a difference to the course of the illness or materially reduce the symptoms

However, treatment of cases with certain antibiotics such as erythromycin can shorten the contagious period (1st stage of the disease)

Since diagnosis seldom occurs during this time, antibiotic therapy is usually ineffective at decreasing the length of the illness

Prevention

The single most effective control measure is maintaining the highest possible level of immunization in the community

A child needs five DTP shots (Diptheria, Tetanus, Pertussis) at 2, 4, 6 and 15 months of age followed by a booster at 4-6 years for complete protection

People with Pertussis should stay away from infants and young children

Case Summary

6 year boy diagnosed with whooping cough

No antibiotics given Mother was advised to used a humidifier,

encourage drinking plenty of fluids, and to return to ER if he had difficulty breathing

References

Pertussis, CDC Public Health Image Library, http://phil.cdc.gov/phil/results.asp, Last accessed on 11/08/04.

Credits

This case was prepared by

Janell Jones, MT(ASCP) while she was a

Medical Technology student in the

2004 MT Class at William Beaumont

Hospital, Royal Oak, MI.