CLED medium is used in preference in macconkey agar in relation to culture of organism involved in urine infection the reason is ?
**Core Concept**
CLED (Cysteine Lactose Electrolyte Deficient) medium and MacConkey agar are both selective media used for culturing bacteria from urine samples. They differ in their composition and selective properties, which affect the types of bacteria they can grow.
**Why the Correct Answer is Right**
CLED medium is preferred over MacConkey agar for culturing organisms involved in urinary tract infections (UTIs) because it is less inhibitory and allows for the growth of a broader range of bacteria, including those that are not lactose-fermenting. This is particularly useful for identifying bacteria that do not produce lactose, such as Proteus, Providencia, and Klebsiella species, which are common causes of UTIs. The CLED medium's less selective environment also allows for the growth of fastidious organisms, such as Enterococci and some species of Staphylococci.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the comparison between CLED medium and MacConkey agar in the context of UTI culture.
* **Option B:** This option is incorrect because MacConkey agar is actually more selective than CLED medium, which can inhibit the growth of certain bacteria.
* **Option D:** This option is incorrect because CLED medium is not typically used for the isolation of fungi, which are often the primary concern in cases of fungal UTIs.
**Clinical Pearl / High-Yield Fact**
When culturing urine samples, it's essential to consider the patient's symptoms, medical history, and laboratory results to select the most appropriate culture medium. CLED medium is often used as a secondary culture to confirm the identity of bacteria isolated on MacConkey agar or other selective media.
**Correct Answer:** C.