Bacteria That Produce Dangerous Toxins


Diphtheria is an infectious disease caused by the bacterial microorganism known as Corynebacterium diphtheriae. Some strains of this bacterium produce a toxin, and it is this toxin that causes the most serious complications of diphtheria. The bacteria produce a toxin because they themselves are infected by a certain type of virus called a phage.

According to the US Center for Disease Control and Prevention (CDC), Diphtheria bacteria spread from person to person, usually through respiratory droplets, like coughing or sneezing. People can also get sick from touching infected open sores or ulcers.

Affects the Mucous Membranes

Diphtheria is a contagious disease spread through physical contact or droplets during coughing and sneezing. Occasionally, diphtheria may be transmitted from skin sores. It may also spread through someone who carries the bacteria but shows no symptoms. Although serious and highly contagious, there is a vaccine for the disease, which should be administered for diphtheria prevention.

Diphtheria is caused by a bacterium called Corynebacterium diphtheriae. This disease mainly affects the mucous membranes of the upper airway passage and occasionally affects the skin. Some of the risk factors include overcrowded areas, poor hygiene and lack of immunization. The diphtheria bacteria usually live in the nose and the throat of an infected person. Some infected individuals may become carriers of the bacteria without displaying any symptoms.

Toxin May Spread Through the Bloodstream

Diphtheria symptoms usually appear within two to four days of the infection. They may include sore throat, hoarseness, low-grade fever and general body weakness, difficulty in swallowing and breathing due to a thick membrane that forms in the nose and throat and neck swelling due to enlarged lymph glands in severe cases. Only toxin-producing strains of the bacteria can cause severe disease by spreading the toxin in the infected person’s bloodstream. These bacteria strains may infect the skin and produce skin sores.

In more serious cases, the respiratory infection may spread beyond the throat due to toxin released by the bacteria. The diphtheria toxin may spread through the bloodstream to other parts of the body, such as the heart and the nerves. 

Left untreated, diphtheria can lead to:

Breathing problems: Diphtheria-causing bacteria may produce a toxin. This toxin damages tissue in the immediate area of infection — usually, the nose and throat. The infection produces a tough, grey-coloured membrane composed of dead cells, bacteria, and other substances at that site. This membrane can obstruct breathing.

Heart damage: The diphtheria toxin may spread through your bloodstream and damage other tissues in your body, such as your heart muscle, causing such complications as inflammation of the heart muscle (myocarditis). Heart damage from myocarditis may be slight or severe. At its worst, myocarditis can lead to congestive heart failure and sudden death.

Nerve damage: The toxin can also cause nerve damage. Typical targets are nerves to the throat, where poor nerve conduction may cause difficulty swallowing. Nerves to the arms and legs also may become inflamed, causing muscle weakness.

Available Treatment Options 

Diphtheria is a serious disease and may be fatal despite proper treatment in some cases. Complications are less frequent when the infection is limited to the skin. Untreated people who are infected with the diphtheria bacteria are usually contagious for up to two weeks and seldom longer than four weeks. After starting antibiotics, the infected person usually becomes non-contagious in 48 hours. Some persons continue to carry the bacteria, so antibiotic therapy should be continued until the infected person tests negative for diphtheria.

Certain antibiotics, such as penicillin and erythromycin, can be prescribed for the treatment of diphtheria. Diphtheria antitoxin may be available to prevent the disease from getting worse.

How can diphtheria be prevented?

The single most effective control measure to prevent diphtheria is vaccination. Diphtheria toxoid usually is combined with tetanus toxoid and pertussis vaccine to form a triple vaccine known as DTaP. This vaccine is given starting at approximately two months of age. Multiple doses are needed to ensure protection. Immunity wanes, therefore, adolescents and adults are recommended to receive a booster vaccination called Tdap. After receiving Tdap, persons should receive tetanus and diphtheria toxoid (Td) every ten years. If you have any concerns about diphtheria, talk to a healthcare provider or contact them via telemedicine App such as the Global Telehealth Exchange (GTHE).