Corynebacterium diphtheriae is the bacterium that causes the disease diphtheria. C. diphtheriae is a rod-shaped, Gram-positive, nonspore-forming, and nonmotile bacterium. The disease occurs primarily in
tropical regions
and underdeveloped countries, but has been known to appear throughout the world.
Where does Corynebacterium come from?
Corynebacterium species occur commonly in
nature in soil, water, plants, and food products
. The nondiphtheiroid Corynebacterium species can even be found in the mucosa and normal skin flora of humans and animals.
Where did diphtheria come from?
Diphtheria is an acute, bacterial disease caused by toxin-producing strains of Corynebacterium diphtheriae. The name of the disease is derived from
the Greek diphthera, meaning ‘leather hide
. ‘ The disease was described in the 5th century BCE by Hippocrates, and epidemics were described in the 6th century AD by Aetius.
Where is Corynebacterium diphtheriae found?
Corynebacterium diphtheriae infects
the nasopharynx or skin
.
How is Corynebacterium diphtheriae acquired?
Gene for the diphtheria toxin is carried in genome of a bacteriophage. C. diphtheria strains must contain a bacteriophage (beta-phage), acquired
by transduction from other C
. diphtheria strains, in order to express the toxin.
How serious is Corynebacterium?
Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make toxin (poison). It can lead to
difficulty breathing, heart failure, paralysis, and even death
. CDC recommends vaccines for infants, children, teens, and adults to prevent diphtheria.
What part of the human body does Corynebacterium colonize?
C. diphtheriae usually colonize a local lesion in
the upper respiratory tract
(although cutaneous diphtheria can occur as well) where the toxin secreted by the bacteria cases necrotic injury to epithelial cells.
Where is diphtheria most commonly found?
Endemic in many countries in
Asia
, the South Pacific, the Middle East, Eastern Europe and in Haiti and the Dominican Republic. Since 2016, respiratory diphtheria outbreaks have occurred in Indonesia, Bangladesh, Myanmar, Vietnam, Venezuela, Haiti, South Africa, and Yemen.
How can diphtheria be prevented?
Vaccination
.
Keeping up to date with
recommended vaccines is the best way to prevent diphtheria. In the United States, there are four vaccines used to prevent diphtheria: DTaP, Tdap, DT, and Td. Each of these vaccines prevents diphtheria and tetanus; DTaP and Tdap also help prevent pertussis (whooping cough).
Who is most likely to get diphtheria?
Children under 5 and adults over 60 years old
are particularly at risk for getting it. People living in crowded or unclean conditions, those who aren’t well nourished, and children and adults who don’t have up-to-date immunizations are also at risk.
How is Corynebacterium transmitted?
The primary modes of dissemination are by
airborne respiratory droplets, direct contact with droplets, or infected skin lesions
.
What are the types of diphtheria?
There are two types of diphtheria:
respiratory and cutaneous
. Respiratory diphtheria involves the nose, throat and tonsils, and cutaneous diphtheria involves the skin. Cutaneous diphtheria is discussed below.
When was the last case of diphtheria in the United States?
Diphtheria is rare in the United States, with only two cases reported between 2004 and
2015
. In recent years, diphtheria has been in the headlines in three countries where the disease had been virtually eliminated — Venezuela, Yemen and Bangladesh.
What is the main cause of diphtheria?
Diphtheria is a
serious infection caused by strains of bacteria called Corynebacterium diphtheriae
that make a toxin (poison). It is the toxin that can cause people to get very sick. Diphtheria bacteria spread from person to person, usually through respiratory droplets, like from coughing or sneezing.
What are the long term effects of diphtheria?
Damage to the heart muscle (myocarditis) Nerve damage
(polyneuropathy) Loss of the ability to move (paralysis) Kidney failure.
What is black diphtheria?
The
throat infection
causes a gray to black, tough, fiber-like covering, which can block your airways. In some cases, diphtheria infects your skin first and causes skin lesions. Once you are infected, the bacteria make dangerous substances called toxins.
