Bordetella pertussis

Bordetella pertussis is the pathogen that causes whooping cough. In our daily life, we often hear parents taking their children to get the "DPT" vaccine. What is the "DPT" vaccine? In fact, the "DPT" vaccine mainly refers to the vaccines against the three pathogens: diphtheria, pertussis, and tetanus. Generally speaking, children between 3 months and 6 years old need to be vaccinated.

What we are more familiar with about the "DPT" vaccine should be the "bai" in it. "bai" refers to Bordetella pertussis, which is an inactivated Bordetella pertussis. It is a vaccine with the immunogenicity of Bordetella pertussis but without toxicity. Let's learn about it below.

Bordetella pertussis is the causative agent of whooping cough in humans. Bordetella pertussis is an oval, short rod that measures 0.5-1.5×0.2-0.5um. It belongs to the genus Bordetella and has no flagella or spores. Gram stain negative. Toluidine blue staining revealed bipolar metachromatic granules. It is an obligate aerobe and has high nutritional requirements when it is initially isolated and cultured. It needs potato blood glycerol agar medium (i.e., Bowdoin medium) to grow. After 2-3 days of incubation at 37°C, small, round, smooth, raised, silver-gray, opaque colonies with a fuzzy hemolytic ring around them can be seen. Liquid culture showed uniform turbid growth with a small amount of sticky precipitation. The biochemical reaction is weak. Sugars are generally not fermented, but sucrose and lactose are decomposed. Acid is produced but no gas is produced. H2S and indole are not produced. The catalase test is positive.

After being infected with whooping cough, a variety of specific antibodies may appear, and immunity is relatively long-lasting. Only a small number of patients may be infected again, and the recurrence is also milder. The secretory LGA in the local mucosa has the function of preventing bacteria from adhering to the cilia of tracheal mucosal cells, and its anti-infection effect is more important than the antibodies in the serum. The role of cell-mediated immunity in Bordetella pertussis infection remains unclear.

After infection with Bordetella pertussis, the patient needs to be isolated for seven weeks from the onset of the disease. Prevention is mainly based on active immunization. In my country, the commonly used triple vaccine is diphtheria toxin, pertussis phase I inactivated vaccine of Bordetella pertussis, and tetanus toxoid, DPT. The target population is children under one year old. Vaccination can significantly reduce the morbidity and mortality rates. However, the killed bacteria vaccines currently used have certain side effects, and further improvements are needed in terms of safety and immunogenicity. Treatment can be with erythromycin, ampicillin, etc.

The above are the main functions of Bordetella pertussis. From the above we can see that Bordetella pertussis vaccine is actually an immunogenic vaccine. After vaccination with this vaccine, our body can produce antibodies against Bordetella pertussis. Therefore, we should get this vaccine as required.