UPSC Prelims 2022 Q37: Science & Technology – Health & Diseases
Consider the following statements:
1. Biofilms can form on medical implants within human tissues.
2. Biofilms can form on food and food processing surfaces.
3. Biofilms can exhibit antibiotic resistance.
Which of the statements given above are correct?
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
Biofilms — communities of microbes stuck to surfaces
A biofilm is a colony of bacteria or fungi living inside a slimy extracellular matrix they make themselves.
| Statement | Verdict | Example |
|---|---|---|
| 1. Form on medical implants | Correct | Catheters, heart valves, artificial joints; cause hard-to-treat infections |
| 2. Form on food and food-processing surfaces | Correct | Steel tanks, pipes, conveyor belts; *Listeria* and *Salmonella* biofilms |
| 3. Show antibiotic resistance | Correct | Up to 1,000 times more resistant than free-floating bacteria |
Why biofilms resist antibiotics:
| Reason | Explanation |
|---|---|
| Matrix barrier | Slows drug entry |
| Dormant 'persister' cells | Survive drugs that target active cells |
| Gene sharing | Resistance genes spread easily between cells |
Everyday example: dental plaque is a biofilm.
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. It leaves out antibiotic resistance, the main medical worry about biofilms.
- (b) Incorrect. It leaves out medical implants, a major site of biofilm infections.
- (c) Incorrect. It leaves out food-processing surfaces, where biofilms threaten food safety.
- (d) CORRECT. Biofilms form on implants and food surfaces and are highly resistant to antibiotics.
Key point
Biofilms = microbes in a self-made slime; grow on implants, pipes and food equipment; very resistant to antibiotics.
Remember
Biofilms form on implants and food surfaces and resist antibiotics.
Common mistakes
- Thinking biofilms form only in the body; they grow on any moist surface.
- Forgetting that dental plaque is a biofilm.
- Underestimating resistance — biofilms can survive far higher antibiotic doses.
Exam tip
Biofilm = bacterial city with walls. Walls block antibiotics, and cities can be built anywhere.
Sources
- ICMR — Antimicrobial Resistance Surveillance reports
- NCERT Class XII — Biology, Ch 8 (Microbes in Human Welfare)