What is the Difference Between Listeria and Salmonella

The main difference between Listeria and Salmonella is that Listeria causes listeriosis, an infection caused by eating food contaminated with bacteria, whereas Salmonella causes salmonellosis with less intense diarrhea, fever, and stomach cramps.

Listeria and Salmonella are two types of pathogenic bacteria. They are non-spore-forming, facultative anaerobic bacteria.

Key Areas Covered

1. What is Listeria
– Definition, Characteristics, Importance
2. What is Salmonella
– Definition, Characteristics, Importance
3. Similarities Between Listeria and Salmonella
– Outline of Common Features
4. Difference Between Listeria and Salmonella
– Comparison of Key Differences

Key Terms

Listeria, Salmonella

What is Listeria

Listeria is a genus of bacteria that acts as an intracellular parasite in mammals. It is a Gram-positive, rod-shaped, facultative anaerobic bacterium. However, it does not produce endospores. L. monocytogenes is the major human pathogen of the genus Listeria. Generally, it causes a relatively rare bacterial infection called listeriosis. This bacterial disease is caused when the food is contaminated with the bacteria listeria. It can also cause serious illnesses in pregnant women and newborns. Adults with weakened immune systems are also affected by the disease.

Figure 1: Listeria

Furthermore, in humans, listeriosis is a serious illness, and the case-fatality rate of the disease is 20%. Sepsis and meningitis are the two clinical manifestations of the disease. Encephalitis often complicates meningitis and the disease condition is called meningoencephalitis. Normally, this type of pathology is uncommon for a bacterial infection.

What is Salmonella

Salmonella is a genus of Gram-negative bacteria of the family Enterobacteriaceae. Salmonella species are rod-shaped, non-spore-forming, and predominantly motile. Peritrichous flagella occur all around the cell body of Salmonella. More importantly, Salmonella is a chemotroph that obtains its energy from oxidation and reduction reactions using organic sources. It is also a facultative anaerobe capable of generating ATP with oxygen when it is available; when oxygen is not available, it uses other electron acceptors for fermentation.

Figure 2: Salmonella

Moreover, Salmonella is an intracellular pathogen that causes salmonellosis. However, the ingestion of contaminated food is the main cause of the forming disease. In general, there are two types of Salmonella serotypes occur as typhoidal and nontyphoidal. Nontyphoidal serotypes are zoonotic and they can transfer from animal to human and human to human. They only invade the gastrointestinal tract and cause salmonellosis. Typhoidal serotypes, on the other hand, can only transfer from human to human and cause typhoid fever.

Similarities Between Listeria and Salmonella

• Listeria and Salmonella are two intracellular pathogens that cause diseases due to the ingestion of contaminated food.
• Both are facultative anaerobic bacteria that are non-spore-forming.

Difference Between Listeria and Salmonella

Definition

Listeria refers to a type of bacterium that infects humans and other warm-blooded animals through contaminated food, while Salmonella refers to a bacterium that occurs mainly in the gut, especially a serotype causing food poisoning.

Gram Staining

Listeria is a Gram-positive bacterium while Salmonella is a Gram-negative bacterium.

Causing Diseases

Listeria causes listeriosis while Salmonella causes both salmonellosis and typhoid fever.

Symptoms

The symptoms of listeriosis are fever, muscle aches, headache, stiff neck, confusion, loss of balance, and convulsions while the symptoms of salmonellosis are diarrhea, fever, and stomach cramps.

Conclusion

In brief, Listeria and Salmonella are two types of intracellular pathogens that cause diseases in humans. Both are non-spore-forming, facultative anaerobes. However, Listeria is a Gram-positive bacterium while Salmonella is a Gram-positive bacterium. Moreover, Listeria causes listeriosis, and Salmonella causes salmonellosis while the typhoid serotypes of Salmonella cause typhoid fever. In addition, the main symptoms of listeriosis are fever, muscle aches, headache, stiff neck, confusion, loss of balance, and convulsions, while the main symptoms of salmonellosis include diarrhea, fever, and stomach cramps. Therefore, the main difference between Listeria and Salmonella is the type of disease conditions formed by each bacterium.

References:

1. “Listeria (Listeriosis).” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 30 Sept. 2022
2. “Salmonella Infection.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 29 Apr. 2022,

Image Courtesy:

1. “Listeria monocytogenes PHIL 2287 lores.” By Ed Uthman – Own work (Public Domain) via Commons Wikimedia
2. “the-genus-salmonella-is-a-member-of-the-taxonomic-family-enterobacteriaceae” By Janice Haney Carr – Own Work (CC0) via Commons Wikimedia