Description

Intended use
Recommended as a general culture medium for cultivation of less fastidious microorganisms from clinical and non-clinical
samples. It can be enriched with blood or other biological fluids.
Composition**
Ingredients Gms / Litre
Peptone 5.000
Sodium chloride 5.000
HM peptone B# 1.000
Yeast extract 2.000
Agar 15.000
Final pH ( at 25°C) 7.4±0.2
**Formula adjusted, standardized to suit performance parameters
# – Equivalent to Beef extract
Directions
Suspend 28.0 grams in 1000 ml purified/distilled water. Heat to boiling to dissolve the medium completely. Sterilize by
autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 45-50°C. Mix well and pour into sterile Petri plates.
Principle And Interpretation
Nutrient media are basic culture media used for maintaining microorganisms, cultivating fastidious organisms by enriching
with serum or blood and are also used for purity checking prior to biochemical or serological testing (1,2). Nutrient Agar is
ideal for demonstration and teaching purposes where a more prolonged survival of cultures at ambient temperature is often
required without risk of overgrowth that can occur with more nutritious substrate. This relatively simple formula has been
retained and is still widely used in the microbiological examination of variety of materials and is also recommended by
standard methods. It is one of the several non-selective media useful in routine cultivation of microorganisms (3,4). It can be
used for the cultivation and enumeration of bacteria which are not particularly fastidious. Addition of different biological
fluids such as horse or sheep blood, serum, egg yolk etc. makes it suitable for the cultivation of related fastidious organisms.
Peptone, HM peptone B and yeast extract provide the necessary nitrogen compounds, carbon, vitamins and also some trace
ingredients necessary for the growth of bacteria. Sodium chloride maintains the osmotic equilibrium of the medium.
Type of specimen
Clinical samples – pathological material, Food and dairy samples; Water samples
Specimen Collection and Handling:
For clinical samples follow appropriate techniques for handling specimens as per established guidelines (5,6).
For food and dairy samples, follow appropriate techniques for sample collection and processing as per guidelines (3,4,7).
For water samples, follow appropriate techniques for sample collection, processing as per guidelines and local standards.(8)
After use, contaminated materials must be sterilized by autoclaving before discarding.
Warning and Precautions :
In Vitro diagnostic use. For professional use only. Read the label before opening the container. Wear
protective gloves/protective clothing/eye protection/ face protection. Follow good microbiological lab practices
while handling specimens and culture. Standard precautions as per established guidelines should be followed
while handling clinical specimens. Safety guideline