Among the following chemical disinfectants, which is the most commonly used agent for high-level disinfection of endoscopes in Indian hospitals?

Question

Accepted Answer

B. Glutaraldehyde 2%. ## High-Level Disinfection of Endoscopes

**Key Point:** Glutaraldehyde 2% is the most widely used and most common high-level disinfectant for endoscopes in Indian hospital practice.

### Why Glutaraldehyde Is the Standard

Glutaraldehyde is an aldehyde that:
- Rapidly inactivates bacteria, viruses, fungi, and spores
- Achieves high-level disinfection in 3–10 hours (depending on concentration and temperature)
- Is cost-effective and widely available in India
- Has been the gold standard for endoscope disinfection for decades
- Is recommended by WHO and most national infection control guidelines

### Mechanism of Action

Glutaraldehyde cross-links proteins and nucleic acids in microorganisms, causing:
1. Denaturation of enzymes
2. Disruption of cell membrane integrity
3. Inactivation of nucleic acids
4. Rapid bactericidal, virucidal, and sporicidal activity

### Comparison of High-Level Disinfectants

| Agent | Concentration | Contact Time | Sporicidal | Cost | Common Use |
|-------|---------------|--------------|-----------|------|------------|
| Glutaraldehyde | 2% | 3–10 hrs | Yes | Low | Endoscopes (most common) |
| Peracetic acid | 0.35% | 3–12 min | Yes | High | Automated systems |
| Hydrogen peroxide | 6% | 30 min–6 hrs | Yes (high conc.) | Medium | Endoscopes (alternative) |
| Chlorhexidine | 4% | 30 min | No | Low | Intermediate disinfection only |

**High-Yield:** Glutaraldehyde is sporicidal (kills bacterial spores) and is therefore suitable for high-level disinfection, whereas chlorhexidine is NOT sporicidal and is only intermediate-level.

**Mnemonic:** **GAPS** — Glutaraldehyde, Aldehydes, Peracetic acid, Sporicidal (these three are high-level disinfectants).

### Clinical Pearl

In Indian hospitals, glutaraldehyde 2% remains the most practical choice because:
- It is inexpensive
- Requires no special equipment (manual soaking)
- Has a long shelf life when properly stored
- Effective against all microorganisms including spores
- Widely available and familiar to staff

**Warning:** Chlorhexidine, despite being commonly available, is NOT suitable for high-level disinfection of endoscopes because it is not sporicidal and does not achieve the required microbicidal spectrum.

Answer

A. Hydrogen peroxide 6%

Answer

C. Chlorhexidine 4%

Answer

D. Peracetic acid 0.35%

Among the following chemical disinfectants, which is the most commonly used agent for high-level disinfection of endoscopes in Indian hospitals?

Explanation

High-Level Disinfection of Endoscopes

Why Glutaraldehyde Is the Standard

Mechanism of Action

Comparison of High-Level Disinfectants

Clinical Pearl

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Agent	Concentration	Contact Time	Sporicidal	Cost	Common Use
Glutaraldehyde	2%	3–10 hrs	Yes	Low	Endoscopes (most common)
Peracetic acid	0.35%	3–12 min	Yes	High	Automated systems
Hydrogen peroxide	6%	30 min–6 hrs	Yes (high conc.)	Medium	Endoscopes (alternative)
Chlorhexidine	4%	30 min	No	Low	Intermediate disinfection only