The main difference between spirilla and Spirochetes is that spirilla have relatively short and rigid cells whereas spirochetes have longer and more flexible cells. Furthermore, the motility mechanisms of spirilla are based on polar flagella while the motility mechanisms of spirochetes are based on axial filaments.
Key Areas Covered
1. What are Spirilla
– Definition, Characteristics, Importance
2. What are Spirochetes
– Definition, Characteristics, Importance
3. What are the Similarities Between Spirilla and Spirochetes
– Outline of Common Features
4. What is the Difference Between Spirilla and Spirochetes
– Comparison of Key Differences
Cell Wall, Motility, Spiral Bacteria, Spirilla, Spirochetes
What are Spirilla
Spirilla are spiral bacteria classified in the genus Spirillum under the family Spirillaceae. The two main characteristic features of spirilla are the presence of a rigid cell wall and the motility mechanism based on polar flagella. Additionally, spirilla are large and elongated cells.
Furthermore, Spirilla are widespread in a number of environments. Also, they are aerobic bacteria with a helical shape. However, some species of spirilla such as Spirillum minor can cause rat bite fever in humans. Campylobacter, which is another spiral bacterial genus with comma shape bacteria, contains pathogenic species that cause campylobacteriosis, a type of intestinal infection accompanied by diarrhea.
What are Spirochetes
Spirochetes are the spiral bacteria characterized by the presence of a flexible cell wall and axial filaments-based motility mechanisms. Moreover, the axial filaments contain fibrils extending toward each other between two layers of the cell wall. However, spirochetes are difficult to visualize under the light microscope due to their very slender nature. Additionally, they are very difficult to cultivate and stain by Gram-staining.
Moreover, some spirochetes live in aquatic environments. Others are parasitic in arthropods and warm-blooded animals. Additionally, they cause diseases such as Lyme disease (by Borrelia burgdorferi) and syphilis (by Treponema pallidum). Also, Leptospira interrogans serves as an agent of leptospirosis.
Similarities Between Spirilla and Spirochetes
- Spirilla and Spirochetes are two groups of spiral bacteria.
- Furthermore, they are classified based on the number of twists per cell thickness, flexibility, and motility.
- Also, both types of bacteria can be pathogenic.
Difference Between Spirilla and Spirochetes
Spirilla refer to a bacteria with a rigid, spiral structure found in stagnant water and sometimes causing disease, while spirochetes refer to a flexible, spirally twisted bacteria especially, one that causes syphilis. Thus, this is the main difference between spirilla and spirochetes.
Moreover, there is a difference between spirilla and spirochetes in their classifications too. The spirilla is a genus while spirochetes are a phylum.
The spirilla are rigid while spirochetes are flexible.
Type of Flagella
Also, another difference between spirilla and spirochetes is that while Spirilla have external flagella, spirochetes have internal flagella.
Gram staining is one other difference between spirilla and spirochetes. Spirilla are Gram-negative bacteria while spirochetes are difficult to Gram stain.
Moreover, spirilla are large, 1.4 to 1.7 μm in diameter and up to 60 μm in length, while spirochetes are giants, 0.2-0.3 μm in diameter and 20-30 μm in length (Borrelia).
Furthermore, Spirilla are aerobic bacteria while spirochetes are obligate or facultative anaerobes. Hence, this is another difference between spirilla and spirochetes.
In addition, Spirilla cause rat bite fever in humans and campylobacteriosis while spirochetes cause Lyme disease and syphilis.
Spirilla is a genus of spiral bacteria characterized by the presence of a rigid cell wall and polar flagella for motility. Also, they are gram-negative bacteria. They are aerobes. On the other hand, spirochetes are a phylum of spiral bacteria characterized by the presence of a flexible cell wall and axial filament-based motility. However, they are difficult to cultivate. Also, they are much larger than spirilla. Hence, the main difference between spirilla and spirochetes is morphology and pathogenicity.
1. Todar, Kenneth. Bacterial Pathogens of Humans, Available Here.