Explain how the use of antibiotics has led to antibiotic-resistant strains of bacteria becoming a common cause of infection acquired when in hospital.

Scientists suggested that factors, other than antibiotic use, led to the increase in antibiotic-resistant C. difficile infections. One suggested factor is people eating more trehalose in their diet.

Trehalose is a disaccharide formed from two glucose molecules.

Name another disaccharide formed from two glucose molecules.

Scientists investigated the effect of trehalose on the growth rate of C. difficile. They grew populations of non-resistant and antibiotic-resistant C. difficile on separate agar plates with: • no carbohydrate added • trehalose added.

They measured the growth rate of the C. difficile.

Figure 2 shows the scientists' results.

Describe how the scientists could use aseptic techniques to transfer 0.3 cm3 of C. difficile in liquid culture from a bottle onto an agar plate.

Use Figure 2 to evaluate whether more trehalose in the diet could be a factor in the increased number of antibiotic-resistant C. difficile infections.