Tiny germs live in food. They can be in eggs or meat. These germs can make us sick. We must cook our food well. This keeps us safe and healthy. Do you wash your hands?
Tiny germs can live in food. They often live in birds and cows.
These germs can hide inside eggs. They can spread from the egg white to the yolk.
Cold air in a fridge slows them down. But it does not kill them all.
You must cook food well to stay safe. This is very important for eggs and meat.
Some germs can live in dry, hot places. They can even live inside our bodies.
These germs can make people feel very sick. It is good to eat cooked food.
Salmonella enterica is a tiny germ. It is shaped like a rod. This germ is a bacterium. It can live in many places. It lives in soil and animal bedding. It also lives in the guts of animals.
Many people get sick from eating bad food. Poultry like chickens and turkeys are main sources. Most human cases come from eggs or chicken. Some germs hide in the egg white. As an egg gets old, they move to the yolk.
Cold air in a fridge slows them down. But it does not kill them all. You must cook food well to stay safe. Heat can kill these germs.
These germs are very tough. They can live in hot and dry places. They can also live inside the human body. This germ has been around for a long time. Scientists found it in human remains from 6,500 years ago.
Some types of this germ cause typhoid fever. This is a serious sickness. Young children and old people are at higher risk. Doctors may use medicine called antibiotics to help. People should also drink plenty of fluids.
Salmonella enterica is a tiny, rod-shaped bacterium. It is a very tough living thing. This germ can live in many different places. It stays in soil and animal bedding. It also lives inside the guts of animals.
Many of these germs can make people sick. This is called salmonellosis. It is the leading foodborne germ in the United States. It causes many deaths and costs a lot of money. This germ is very good at surviving. It can live for a long time in hot, dry places. It can even survive inside the human body.
This germ moves from animals to people in a few ways. Poultry like chickens and turkeys are the main sources. Most human cases come from eating eggs or chicken. Sometimes the germ starts in the egg white. As an egg gets old at room temperature, the yolk membrane breaks. The germ can then spread into the yolk.
Cold air in a fridge slows the germ down. However, freezing does not kill all of them. You must cook food well to stay safe. Heat can kill these germs. Companies use pasteurizing or food irradiation to kill them in foods like ice cream.
Scientists have found that this germ is very old. They found its DNA in human remains from 6,500 years ago. These remains were found across Western Eurasia. This shows the germ was spreading a long time ago. In the 16th century, it caused a big sickness in Mexico. This sickness was called cocoliztli. It spread very fast in 1545. Over the next hundred years, it killed up to 90% of the Indigenous people there.
There are many different types of this bacterium. It has six main subspecies. One is called arizonae, which is named after Arizona. It is often found in snakes. Another type is called S. Typhi. This specific type causes typhoid fever. There are over 2,500 different versions called serovars. Some famous ones include S. Enteritidis and S. Typhimurium.
Most versions that make humans sick belong to the enterica subspecies. These germs use special proteins to stick to host cells. This helps them grow inside a living thing.
Getting sick from this germ can be very hard on the body. Children under five and elderly people are at higher risk. People with weak immune systems must be extra careful. If the sickness spreads through the body, it can cause anemia. It can also cause septicaemia. Once these symptoms appear, the death rate is 15%.
Doctors often treat people with antibiotics. These are medicines like fluoroquinolones. Patients also need to drink plenty of extra fluids. Understanding these germs helps us keep our food and animals safe.
Salmonella enterica is a rod-shaped, Gram-negative bacterium. It is a member of the Salmonella genus. This microorganism is a facultative anaerobe, meaning it can grow with or without oxygen. It is also a flagellate, which means it uses whip-like structures to move. Salmonella enterica is a very resilient organism. It can survive for long periods in hot and dry environments. This toughness helps it survive in harsh places like farm settings. It also helps the bacteria survive the difficult environment of the gastrointestinal tract.
The bacterium is divided into six distinct subspecies. These are arizonae, diarizonae, houtenae, salamae, indica, and enterica. Most versions that cause human disease belong to the enterica subspecies. Each subspecies has many different serovars, which are variations based on antigenic specificity. There are over 2,500 known serovars. Some important serogroups include S. Typhi, which causes typhoid fever. Other notable serovars are S. Enteritidis, S. Paratyphi, S. Typhimurium, and S. Choleraesuis. The subspecies arizonae is named after the state of Arizona. It is commonly found in cold-blooded animals like snakes.
Salmonella enterica uses complex mechanisms to infect hosts. The bacteria produce secreted proteins that are vital to their pathogenesis, or the process of causing disease. They possess many adhesins, which are proteins that help the bacteria stick to host cells. These adhesins also help the bacteria form biofilms. Once they attach, secreted proteins help the bacteria invade host cells. They also help the bacteria multiply inside those cells. Regulatory proteins, such as IgaA, help the bacteria maintain their outer envelope. These proteins also help the bacteria respond to stress during an infection.
The bacteria also have advanced ways to repair their own DNA. When exposed to bile salts, the bacteria experience DNA damage. This exposure can cause specific types of mutations. To fix this, Salmonella enterica uses a process called base excision repair. It also uses an enzyme called RecBCD for recombinational repair. This ability to repair DNA makes the bacteria even more resistant to the environment. Additionally, small nonprotein-coding RNAs, or sRNAs, help regulate the bacteria. For example, an sRNA called AsdA helps regulate DNA replication. This helps the bacteria manage how they divide and grow.
History shows that this bacterium has been with humans for a very long time. Scientists have reconstructed genomes from human remains that are 6,500 years old. These remains were found across Western Eurasia. This suggests that the bacteria were widespread during prehistory. In the 16th century, Salmonella enterica may have caused an epidemic in New Spain, now Mexico. This epidemic was known as cocoliztli. In 1545, the outbreak spread very quickly. Over the next century, the disease killed up to 90% of the Indigenous population.
In the United States, Salmonella enterica is the leading foodborne pathogen. It causes the highest number of deaths and the greatest cost burden from foodborne illness. The primary reservoir, or home, for the bacteria is poultry. About 70% of human cases come from eating contaminated eggs, chicken, or turkey. Bacteria can live in animal intestinal tracts, soil, bedding, and fecal matter. In eggs, the bacteria often start in the egg whites. If an egg stays at room temperature, the yolk membrane can break. This allows the bacteria to spread into the yolk.
Preventing infection requires careful food handling. Refrigeration and freezing can slow the growth of bacteria, but they do not kill all of them. Commercial producers use pasteurizing or food irradiation to kill the bacteria in foods like ice cream. At home, foods made with raw eggs, like mayonnaise or cookies, must be cooked properly. Certain people are at higher risk for serious illness. This includes children under five, the elderly, and immunosuppressed adults. If the disease causes systemic dissemination, it can lead to anemia or septicaemia. Once these complications appear, the mortality rate is 15%. Doctors often treat these cases with antibiotics like fluoroquinolones and plenty of fluids.
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