NAME: Bordetella pertussis
CHARACTERISTICS: Bordetella pertussis are small, gram-negative, encapsulated, non-motile, coccobacilli with outer pili. They are generally about 0.5-1.0 µm in size Footnote 3-Footnote 5. Some have reported that the bacteria are covered with surface slime or biofilm composed of carbohydrates Footnote 6. B. pertussis is a strict aerobe and grows optimally at 35°C to 37°C Footnote 3; however, it is fastidious in its nutritional requirements as it specifically requires nicotinamide supplement Footnote 5, and growth can be inhibited by the presence of fatty acids, metal ions, sulphides, and peroxides in the media Footnote 3. Its production of extracellular toxins such as pertussis toxin (PT), invasive adenylate cyclase, and tracheal cytotoxin greatly contributes to its pathogenicity Footnote 5.
PATHOGENICITY/TOXICITY: B. pertussis is a respiratory pathogen that causes pertussis, also known as whooping cough, a localized infection of the ciliated epithelium of the bronchial tree Footnote 3, Footnote 7. The disease affects mainly children, but adults have also been increasingly reported to be affected Footnote 2, Footnote 8. The pathogen produces toxins which cause local damage to the cilia of epithelial cells, which leads to prolonged illness and pertussisFootnote 2, Footnote 5. Symptoms of pertussis can be either typical (classical) or atypical Footnote 3. Four hundred thousand fatal cases are reported each year Footnote 9.
Typical symptoms occur in three different stages Footnote 3. The first stage is the catarrhal stage. This stage lasts for about 1-2 weeks, and is characterized by non-specific symptoms such as rhinorrhea, sneezing, low-grade fever and cough. The second stage is the paroxysmal stage, lasting for about 1-6 weeks, and is characterized by various pathognomonic symptoms of pertussis such as episodes of paroxysmal cough with a characteristic whooping sound. The paroxysmal cough can also be associated with post-tussive cyanosis and emesis Footnote 2, Footnote 3. The final stage is the convalescent stage. During this stage, the respiratory symptoms gradually decrease although coughing may last for several months Footnote 2, Footnote 3. Atypical pertussis, a less severe respiratory illness which include prolonged, nonparoxysmal cough occurs mainly in older immunized children and adults Footnote 3, Footnote 7. Pertussis infection in infants may cause severe cough, choking, poor feeding, and apnea without paroxysmal cough Footnote 3, Footnote 7, Footnote 10. Serious complications associated with the pertussis are cyanosis, pneumonia, bradycardia, seizures, encephalopathy, refractory pulmonary hypertension, and even death Footnote 2. Complications vary depending upon the age group and occur mainly in infants Footnote 2.
EPIDEMIOLOGY: B. pertussis is of worldwide prevalence as it can exist as a noninvasive parasite of the respiratory tract of mammals, however, 20-40 million cases of pertussis, and 400,000 fatal cases, are reported each year Footnote 9. The last national peak of pertussis infection in Canada occurred in 1998 Footnote 7. Between the years 1998-2004, the incidence of pertussis as well as pertussis-related mortality declined significantly following introduction of the acellular pertussis vaccine (DTaP-IPV-Hib vaccine) in 1998 Footnote 7. In the United States, the rates of pertussis infection moderately increased between the years 1980 and 2000, although larger rate increases were observed in adolescent and adult cases of pertussis Footnote 2, Footnote 9. Infants below the age of 12 months have the highest incidence and mortality associated with pertussis. The incidence rates in this age group have remained stable since 2001 with a range of 71.3–91.6 cases per 100,000.
HOST RANGE: Disease occurs only in humans Footnote 3.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: Transmission of B. pertussis occurs primarily via direct contact or inhalation of airborne droplets Footnote 2, Footnote 11. Symptoms develop following inhalation of the airborne pathogen.
INCUBATION PERIOD: Seven to 10 days, with a range of 4-21 days Footnote 3.
COMMUNICABILITY: It is highly contagious (infects 80-90% of susceptible persons) and is transmitted from human-to-human via contact with discharge from respiratory membranes or inhalation of infectious respiratory droplets Footnote 3, Footnote 11. It is most contagious in the catarrhal and the paroxysmal stages Footnote 2.
RESERVOIR: Humans are the sole reservoir Footnote 3. The main reservoir consists of adults and adolescents with atypical or undiagnosed infection, who may transmit the infection to infants and children Footnote 8.
ZOONOSIS: None Footnote 3.
VECTOR: None Footnote 3.
DRUG SUSCEPTIBILITY/RESISTANCE: Susceptible to erythromycin, macrolides such as azithromycin and clarithromycin, trimethoprim-sulfamethoxazole, floroquinoles such as ciprofloxacin, levofloxacin, and gemifloxacin Footnote 3, Footnote 12.
SUSCEPTIBILITY/RESISTANCE TO DISINFECTANTS: B. pertussis has been shown to be sensitive to glutaraldehyde Footnote 15. In addition most vegetative bacteria are susceptible to low concentrations of chlorine (<1ppm) Footnote 16, Footnote 17, 70% ethanol, phenolics such as orthophenylphenol and ortho-benzyl-paua-chlorophenol, and peracetic acid (0.001% to 0.2%) Footnote 17.
PHYSICAL INACTIVATION: Information specific to B. pertussis is not available; however, most vegetative bacteria can be inactivated by moist heat (121°C for 15 min- 30 min) and dry heat (160-170°C for 1-2 hours) Footnote 18.
SURVEILLANCE: Monitor for symptoms. Diagnosis of B. pertussis can be done using cultures of clinical specimens such as nasopharygeal aspirates and posterior nasopharyngeal swabs Footnote 2, Footnote 3, however, it should be noted that cultures are less sensitive after antimicrobial therapy has been started Footnote 2. Gram-staining or biochemical tests such as PCR, Direct Fluorescent Antibody (DFA), or ELISA can also confirm infection Footnote 2, Footnote 3. PCR is a quicker and more sensitive method, but it is less specific than culture. The Center for Disease Control and Prevention (CDC) recommends the use of both culture and PCR assay for diagnosing pertussis Footnote 2.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Treatment for pertussis is generally supportive. Antibiotic treatment is most effective when given during the catarrhal stage, and can also reduce the risk of transmission when given at paroxysmal stage Footnote 2. A 14-day regimen with erythromycin is recommended for treating pertussis Footnote 2, Footnote 12. Other antibiotics effective for treating pertussis include azithromycin and clarithromycin Footnote 2. These drugs have fewer side effects than erythromycin. For neonates, only azithromycin is recommended Footnote 2.
IMMUNIZATION: Vaccination for control of pertussis infection is given as a combined DTaP vaccine of diptheria, pertussis, and tetanus toxoid Footnote 10. It can be administered along with the vaccine for poliomyelitis and Haemophilus influenzae type b (DTaP-IPV-Hib) to infants at a very young age Footnote 7. A booster dose of DTaP–IPV vaccine can also be given between 4 and 6 years of age Footnote 7, Footnote 10.
PROPHYLAXIS: Antibiotic prophylaxis with erythromycin, azithromycin, and clarithromycin is advocated by both The American Academy of Pediatrics (AAP) and CDC to control pertussis outbreaks Footnote 2. In Canada, azithromycin, clarithromycin, or erythromycin prophylaxis is recommended for close household contacts of pertussis infected patients Footnote 12. Azithromycin was also effective against a hospital-wide outbreak of pertussis Footnote 12.
LABORATORY-ACQUIRED INFECTIONS: Eight cases of B. pertussis infection were reported from a research institution conducting pertussis research Footnote 8. The infections were found among individuals not directly working with the bacteria. They may have acquired the infection through the common laboratory spaces where the research was conducted Footnote 8. Two cases of B. pertussis laboratory acquired infection were also reported from a large Midwestern university Footnote 8. Another B. pertussis infection was reported in a worker who had aerated the liquid cultures of bacteria for the preparation of vaccine Footnote 21.
PRIMARY HAZARDS: Exposure to infectious aerosols, generated during manipulation of pertussis cultures or working with concentrated suspensions of the bacteria, to mucous membranes Footnote 8.
SPECIAL HAZARDS: None.
RISK GROUP CLASSIFICATION: Risk Group 2 Footnote 22.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures Footnote 23.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 23.
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 23.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up Footnote 23.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing Footnote 23.
STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled Footnote 23.
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: October 2010
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada
Although the information, opinions and recommendations contained in this Pathogen Safety Data sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2010