What is the optimum temperature in an autoclave to achieve sterility?

AIIMS Patna NO - 2020

Applied Microbiology & Infection control

Easy

Appeared in: AIIMS Patna NO - 2020

Explanation

Autoclaving uses steam under pressure to achieve sterilization, which is the complete destruction of all microorganisms, including resilient bacterial spores.
The standard parameters for effective steam sterilization are a temperature of 121°C (250°F) maintained for at least 15-30 minutes at a pressure of 15 psi.
This specific combination ensures that the moist heat penetrates the items thoroughly, coagulating the proteins of microorganisms and rendering them non-viable.
The 30-minute duration provides an adequate margin of safety to ensure all items in the load reach the required temperature for the necessary time.

Option B: A temperature of 60°C is used for pasteurization, which is a disinfection method. It reduces the number of pathogens but does not eliminate highly resistant bacterial spores, thus failing to achieve sterility.
Option C: A temperature of 34°C is near human body temperature and falls within the optimal growth range for many mesophilic bacteria. Using this temperature would likely encourage microbial growth rather than inhibit it.
Option D: A temperature of 27°C is close to ambient room temperature. It has no sterilizing or disinfecting effect and allows most microorganisms to survive and multiply.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Principles of Sterilization using Autoclave as background academic context rather than a clinical decision trigger.
Ensuring proper autoclave operation is a critical nursing responsibility to prevent healthcare-associated infections (HAIs) from contaminated surgical instruments, dressings, and other medical equipment.
Nurses must verify that each autoclave cycle has successfully met its parameters by checking physical readouts (temperature, pressure, time) and chemical indicators (e.g., autoclave tape changing color).
Biological indicators (containing spores of Geobacillus stearothermophilus) are the gold standard for confirming sterility and are used periodically to validate autoclave efficacy.

How to Approach the Question

First, identify the core concept of the question, which is 'sterility' via an 'autoclave'.
Recall the fundamental principle of autoclaving: it uses steam under pressure to achieve high temperatures necessary for sterilization.
Remember the standard industry and healthcare parameters for steam sterilization. The most common cycle is 121°C at 15 psi.
Evaluate each option against this standard. 121°C is the correct temperature.
Eliminate the other options. 60°C is for pasteurization, while 27°C and 34°C are near room/body temperature and are ineffective.
Confirm that the time given (30 minutes) is within the acceptable range (typically 15-30 minutes) for the 121°C cycle, making it the correct choice.

Concept Tested & Keywords

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