AST Surgical Technologist Practice Exam

Which term describes a rod-shaped microorganism?

1. Bacillus

2. Cocci

3. Spirilla

4. Vibrio

The correct answer is: Bacillus

The term "Bacillus" specifically refers to rod-shaped microorganisms. Bacilli can be found in various environments and can exist as both beneficial bacteria, such as those involved in fermentation, and pathogenic species that can cause disease. Their rod-like shape is distinctive and is a key morphological characteristic used to classify and identify different types of bacteria. In contrast, cocci denote spherical-shaped bacteria and include various types such as streptococci and staphylococci. Spirilla refer to bacteria that have a spiral shape, which allows for movement via flagella and can often be seen in environments rich in moisture. Vibrio are a specific group of bacteria that are comma-shaped and are often found in aquatic environments, making them distinct from the rod shape categorized under bacilli. Thus, understanding the morphological characteristics of bacteria, such as the rod shape of bacilli, is essential for microbiological classification and can help in determining the appropriate treatment for bacterial infections.