Escherichia coli O157:H7

A pathogenic strain of the bacterium Escherichia coli''

Escherichia coli O157:H7 under a microscope

Escherichia coli O157:H7 is a serotype of the bacterium Escherichia coli and is one of the enterohemorrhagic strains. It is a major cause of foodborne illness and is associated with severe gastroenteritis and hemolytic-uremic syndrome.

Characteristics

E. coli O157:H7 is a Gram-negative bacterium that is facultative anaerobic, meaning it can grow in both the presence and absence of oxygen. It is rod-shaped and belongs to the family Enterobacteriaceae. This strain is distinguished by its ability to produce Shiga toxin, which is responsible for its virulence.

Pathogenesis

The pathogenicity of E. coli O157:H7 is primarily due to its production of Shiga toxin, which can cause damage to the lining of the intestine and lead to bloody diarrhea. The toxin can also enter the bloodstream and cause damage to the kidneys, leading to hemolytic-uremic syndrome, a serious condition that can result in renal failure.

Transmission

E. coli O157:H7 is commonly transmitted through the consumption of contaminated food or water. Common sources include undercooked ground beef, unpasteurized milk, and fresh produce that has been contaminated with fecal matter. Person-to-person transmission can also occur, particularly in settings such as daycare centers and nursing homes.

Symptoms

Infection with E. coli O157:H7 typically begins with abdominal cramps and diarrhea, which can become bloody. Other symptoms may include nausea, vomiting, and fever. In severe cases, the infection can lead to hemolytic-uremic syndrome, characterized by anemia, thrombocytopenia, and acute kidney injury.

Diagnosis

Diagnosis of E. coli O157:H7 infection is typically made by detecting the bacterium in a stool culture. Specialized laboratory tests can identify the presence of the O157:H7 serotype and the production of Shiga toxin.

Treatment

Treatment for E. coli O157:H7 infection is primarily supportive. Rehydration and electrolyte replacement are important to manage dehydration caused by diarrhea. Antibiotics are generally not recommended, as they may increase the risk of complications such as hemolytic-uremic syndrome.

Prevention

Preventive measures include thoroughly cooking meat, avoiding unpasteurized dairy products, and practicing good hygiene such as regular handwashing. It is also important to wash fruits and vegetables thoroughly to remove potential contaminants.

Related pages

• Escherichia coli
• Foodborne illness
• Shiga toxin
• Hemolytic-uremic syndrome