Question

You take a tissue sample from a wound. You look at it under the microscope and see bacteria inside epidermal cells, surrounding the nucleus. Which of the following activities must have occurred to get the bacteria there?

(Select all that apply) Group of answer choices

Attachment

Colonization

Invasion

Toxin production

Replication

Biofilm formation

Answer 1

Answer : Attachment and invasion

Explanation : As the bacteria is now inside the epidermal cells, so the bacteria must have attached to the host and penetrated thereafter. Without attachment penetration to deeper layer of skin tissue was not possible.

As the bacteria is inside the epidermal cells, surrounding the nucleus then we can say it has invaded the host cells. Invasion has enabled these bacteria to get themselves inside the cell. ​​​​​​

So, we can confirm that Attachment as well as invasion must have occurred to get the bacteria there.

The question is mainly concerned about the steps which might have occurred to get the bacteria where it is present now. So, Colonization can't be the right answer as Colonization indicates the presence of bacterial population in host cells. Colonization has no role in getting the bacteria there.

Toxin production occurs after invasion to take control of the host cells and this is not related to getting the bacteria inside epidermal cells.

Replication is the process of making copies of genetic material. It does not help bacteria to get to their target cells.

Biofilm formation is a type of growth when microorganisms (bacteria) attached to a surface and begin to grow together like a matrix. The attachment and the film like growth is facilitated by secretion of extracellular slimy polymers. This process has not occurred here.

Thus Colonization, Toxin production, Replication and Biofilm production can't be the answer of choice.