Difference Between E. Coli and Klebsiella

E. coli and Klebsiella are two common bacteria that can be found in various environments, including soil, water, and the gastrointestinal tract of humans and animals. Although they share some similarities, there are several significant differences between these two types of bacteria.

What is E. Coli?

Escherichia coli is a rod-shaped bacterium of the genus Escherichia, family Enterobacteriaceae. It is facultatively anaerobic, chemoheterotrophic, Gram-negative, nonsporulating species. It is part of the normal microbiota of the lower intestine commonly occurs in the gut of endotherm species.

• The length of E. coli is about 2.0 μm, its diameter is 0.25–1.0 μm.

• Most of the strains of the species are harmless, but there are serotypes which can lead to serious health problems.

• Typically, E. coli colonizes the gastrointestinal tract of a baby in the first 40 hours of its life. It comes with water, food, or from the individuals taking care of the child. When E. coli reaches the large intestine it adheres to the mucus.

• The harmless strains of E. coli provide benefits to the hosts. They produce vitamin K2 and protect the intestine from colonization of pathogenic bacteria.

• E. coli is released into the environment within the feces. In fresh fecal matter, it grows rapidly for 3 days and afterward the numbers slowly decline.

• The fecal–oral transmission of pathogenic strains is the main cause of diseases related to E. coli.

The virulent strains of E. coli can lead to infections of the urinary tract, gastroenteritis, hemorrhagic colitis, neonatal meningitis, Crohn’s disease. The symptoms of infection with a virulent strain include diarrhea, abdominal cramps, vomiting, hemorrhagic colitis, fever.

Virulent strains can cause bowel necrosis and perforation, mastitis, peritonitis, septicemia, and pneumonia. Virulent E. coli can affect healthy individuals of all ages, but most vulnerable are the young children.

The incubation period is between 1 and 10 days, usually 3–4 days. Usually, the infection goes by itself. The patient is advised to rest and drink plenty of fluids to avoid dehydration. In some cases, antibiotics can be applied to shorten the course of the disease, however, this is generally not recommended due to the increasing resistance to commonly used antibiotics.

Some nonpathogenic strains of E. coli are used in the medicine, as probiotic agents, to treat different gastroenterological diseases.

What is Klebsiella?

Klebsiella is a genus of rod-shaped, facultatively anaerobic, non-motile bacteria from Enterobacteriaceae family. They are oxidase-negative, Gram-negative, and have a prominent polysaccharide-based capsule. Klebsiella species are widespread and can be found in soil, water, plants, and animals. Some species are associative nitrogen fixers.

• Klebsiella is a part of the normal human microbiota in the mouth, nose, and intestines.

• In general, the Klebsiella species are thicker and shorter, compared to other representatives of the Enterobacteriaceae family. Their diameter is between 0.3 and 1.5 µm and their length –

0.5 to 5.0 µm. They occur in chains, in pairs, or singly.

• Klebsiella species are part of the normal human microbiota. However, they can behave as opportunistic pathogens.

• Klebsiella can lead to infections of the urinary tract, pneumonia, meningitis, septicemia, infections of soft tissues, diarrhea, etc. Most often infections in human are caused by K. pneumoniae and K. oxytoca.

• Most susceptible to Klebsiella infections are children, elderly people and people with underlying diseases.

• Most of the Klebsiella infections are a result of the use of contaminated invasive medical equipment. The bacteria can be transmitted through the skin after contact with contaminated objects.

• The incubation period of Klebsiella is between 1 and 6 weeks.

Multiple drug resistance is characteristic for Klebsiella. Cephalosporins, aminoglycosides, and chloramphenicol are used to treat the infection. Most strains are resistant to ampicillin.

Klebsiella is a useful bacterium for the plants, due to its ability to fix atmospheric nitrogen and transform it into a usable form.

Differences: E. coli and Klebsiella

Firstly, E. coli and Klebsiella belong to different families of bacteria. E. coli is a member of the family Enterobacteriaceae, while Klebsiella is a member of the family Klebsiellaceae. These two families of bacteria differ in terms of their morphological and physiological characteristics.

Secondly, E. coli and Klebsiella differ in their gram-staining properties. E. coli is a gram- negative bacterium, meaning that it appears red or pink when stained with the Gram stain. In contrast, Klebsiella is a gram-positive bacterium, meaning that it appears blue or purple when stained with the Gram stain. This difference in staining properties is due to differences in the cell wall structure of the two bacteria.

Thirdly, E. coli and Klebsiella differ in their colony morphology. E. coli forms small, smooth, and slightly shiny colonies on agar plates, while Klebsiella forms larger, mucoid, and shiny colonies. The mucoid appearance of Klebsiella colonies is due to the production of a polysaccharide capsule that surrounds the bacterial cells.

Fourthly, E. coli and Klebsiella differ in their metabolic capabilities. E. coli is a facultative anaerobe, meaning that it can survive in both oxygen-rich and oxygen-poor environments. It is also able to ferment lactose, a type of sugar found in milk. In contrast, Klebsiella is an obligate aerobe, meaning that it requires oxygen to survive. It is also able to ferment a wide variety of sugars, including glucose, lactose, and sucrose.

Fifthly, E. coli and Klebsiella differ in their pathogenicity. While some strains of E. coli are harmless and even beneficial to humans, other strains can cause a wide range of illnesses, including diarrhea, urinary tract infections, and meningitis. In contrast, Klebsiella is a common cause of hospital-acquired infections, particularly in individuals with weakened immune systems. It can cause pneumonia, urinary tract infections, and bloodstream infections.

Sixthly, E. coli and Klebsiella differ in their resistance to antibiotics. E. coli is known for its ability to acquire resistance to antibiotics through the horizontal transfer of genes encoding.

The following table highlights the major differences between E. coli and Klebsiella −

Characteristics	E. coli	Klebsiella
Definition	Escherichia coli is a rod-shaped bacterium of the genus Escherichia, family Enterobacteriaceae.	Klebsiella is a genus of rod-shaped bacteria, family Enterobacteriaceae.
Rank in the taxonomic hierarchy	E. coli is a species.	Klebsiella is a genus.
Occurrence	It is part of the normal microbiota of the lower intestine and commonly occurs in the gut of endotherm organisms. It can be found in water, contaminated with feces.	Klebsiella species are widespread and can be found in soil, water, plants, and animals. It is a part of the normal human microbiota in the mouth, nose, and intestines.
Dimensions	The length of E. coli is about 2.0 μm, its diameter is 0.25–1.0 μm.	The length of Klebsiella is between 0.5 and 5.0 µm, its diameter is between 0.3 and 1.5 µm.
Infection	The fecal–oral transmission of pathogenic strains is the main cause of diseases related to E. coli.	Most of the Klebsiella infections are a result of the use of contaminated invasive medical equipment. The bacteria can be transmitted through the skin after contact with contaminated objects.

Conclusion

The virulent strains of E. coli can lead to infections of the urinary tract, gastroenteritis, hemorrhagic colitis, neonatal meningitis, Crohn’s disease.

The virulent strains of Klebsiella can lead to infections of the urinary tract, pneumonia, meningitis, septicemia, infections of soft tissues, diarrhea, etc. Most often infections in human are caused by K. pneumoniae and K. oxytoca.