A special medium inhibits self-destruction and multiplication of microbes, but maintains "Status quo" condition. These are the properties of a/an?

Appeared in: UPRVUNL - 2021

Explanation

Transport media are specifically formulated to preserve microbial viability without allowing for growth or replication.
They contain buffers and salts to maintain pH and osmotic pressure, preventing autolysis (self-destruction).
They have minimal or no nutritional sources, which inhibits multiplication and maintains the original concentration of microbes in the specimen (status quo).
This is essential for specimens that cannot be processed immediately, ensuring diagnostic accuracy.

Option B: Selective media are designed to actively promote the growth of specific desired microorganisms while inhibiting the growth of others. This contradicts the 'inhibits multiplication' and 'status quo' conditions mentioned in the question.
Option C: Differential media are used to distinguish between different types of bacteria growing on the same plate, usually via a color change. They support and allow microbial growth, which is contrary to the question's description.
Option D: Enrichment media are liquid media used to increase the number of a particular microorganism, especially if it is present in low numbers in the specimen. This is the opposite of inhibiting multiplication.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Properties and Types of Microbiological Culture Media as background academic context rather than a clinical decision trigger.
Using the correct transport medium is a critical pre-analytical step in microbiology. Failure to do so can lead to false-negative results if delicate pathogens die, or false-positive/misleading results if commensal organisms overgrow the pathogen.
For a nurse collecting a specimen, knowing whether a transport medium is needed (e.g., for a wound swab for culture) and using the correct one is essential for ensuring the patient receives an accurate diagnosis and appropriate treatment.
What if? If a stool sample for a suspected Shigella infection was sent without a transport medium and experienced a 12-hour delay, the acidic byproducts from the overgrowth of normal gut flora (like E. coli) would lower the pH and kill the more sensitive Shigella bacteria, likely leading to a false-negative culture result.

How to Approach the Question

First, identify the key phrases in the question stem: 'inhibits self-destruction,' 'inhibits multiplication,' and 'maintains "Status quo" condition.'
Understand that these three phrases point to a medium designed for preservation, not for growth.
Next, evaluate each option based on its primary function in microbiology.
Recall or deduce that 'Selective,' 'Differential,' and 'Enrichment' media are all designed to manipulate microbial growth in some way (either by selecting for, differentiating, or increasing it).
Recognize that 'Transport medium' is the only option whose purpose is to keep microbes viable but static during transit, perfectly matching the question's description.

Concept Tested & Keywords

Concept Tested: Properties and Types of Microbiological Culture Media
Stem keywords: special medium, inhibits self-destruction, inhibits multiplication, status quo
Lead-in keywords: properties of a/an
Negative lead-in flag: false

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E6 Microbiology Essentials Sastry 4e Part 1 p. 49-51

Practise the full UPRVUNL - 2021

Attempt every question from this paper in a timed mock, then review the full solution for each one.