Chapter 22, Problem 1VCQ

Figure 22.8 Compared to free-floating bacteria, bacteria in biofilms often show increased resistance to antibiotics and detergents. Why do you think this might be the case?

Summary Introduction

To write:

The bacteria of biofilms show increased resistance to antibiotics and detergents than free-floating bacteria.

Introduction:

The microbial mats or large biofilms may appear as a first prokaryotic life form on Earth, which originated around 3.5 billion years back. These mats are composed of multi-layered sheets of prokaryotes (bacteria and archaea). The primitive microbial mats typically reliant on chemicals from hydrothermal vents to acquire adequate energy and food.

Explanation of Solution

The microbial community is joined together by the extracellular matrix that is a gum-like sticky substance produced by them. The inner bacterial layer is protected by the extracellular matrix and outer layer of cells. The close proximity of cells usually enables the lateral gene transfer, that is, a mechanism of transfer of genes like detergent or antibiotic-resistance genes from one bacterial cell to another. Additionally, an exo-enzyme synthesized by a bacterial cell can destroy antibiotic or detergent and protect neighboring bacteria. This process helps bacterial cells present in the biofilms even if lateral gene transfer does not occur.

Conclusion

Therefore, bacteria present in the biofilms are more resistant to detergent and antibiotic as compared to the free-floating bacteria.