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Technical Data
Antibiotic Assay Medium No. 11 (Neomycin, Erythromycin Assay M004
Agar) (Erythromycin Seed Agar)
Intended use
Recommended for microbiological assay of antibiotics.
Composition**
Ingredients Gms / Litre
Peptone 6.000
Tryptone 4.000
Yeast extract 3.000
HM peptone B# 1.500
Dextrose 1.000
Agar 15.000
Final pH ( at 25°C) 8.3±0.2
**Formula adjusted, standardized to suit performance parameters
# Equivalent to Beef extract
Directions
Suspend 30.5 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 or
dispense as desired.
Advice:
Recommended for the Microbiological assay of Erythromycin, Netilmicin, Gentamicin, Sisomicin, Neomycin,
Paromomycin.
Other Tests :
Cup plate method is carried out using B. pumilis / kanamycin and M. flaves / erythromycin
1) Dilution : 16 mg Kanamycin in 10 ml distilled water
Stock : 1:10 dilution of above solution
concentration stock (ml) Distilled water (ml) zone of inhibition
5 0.25 4.75 15 mm
20 1.00 4.00 20 mm
100 5.00 - 25 mm
2) Dilution : 9 mg Erythromycin in 10 ml distilled water
Stock : 1:10 dilution of above solution
Concentration stock (ml) Distilled water (ml) zone of inhibition
5 0.25 4.75 22 mm
10 0.50 4.50 32 mm
100 5.00 - 41 mm
Principle And Interpretation
Antibiotic Assay media are used in the performance of antibiotic assays. Grove and Randall have elucidated those antibiotic
assays and media in their comprehensive treatise on antibiotic assays (1). Schmidt and Moyer have reported the use
of antibiotic assay medium for the liquid formulation used in the performance of antibiotic assay (2). These media
are recommended by USP (3) and FDA (4).
Nutrients and growth factors are supplied by the ingredients like peptone, tryptone, yeast extract and HM
peptone B. Dextrose provides the carbon and energy source. Agar provides excellent medium for antibiotic diffusion
and gives well-defined zones of inhibition. Higher pH provides the optimal conditions for activity of antibiotic and also
supports the growth of the test organisms.
Please refer disclaimer Overleaf.
HiMedia Laboratories Technical Data
Freshly prepared plates should be used for antibiotic assays. Test organisms are inoculated in sterile seed agar pre-cooled
to 40-45°C and spread evenly over the surface of solidified base agar. All conditions in the microbiological assay
must be controlled carefully.
Type of specimen
Pharmaceutical preparations
Specimen Collection and Handling:
For pharmaceutical samples follow appropriate techniques for handling specimens as per established guidelines (3).
After use, contaminated materials must be sterilized by autoclaving before discarding.
Warning and Precautions :
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 specimens. Safety guidelines may be referred in individual safety data sheets.
Limitations :
1. Freshly prepared plates must be used or it may result in erroneous results.
Performance and Evaluation
Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at
recommended temperature.
Quality Control
Appearance
Cream to yellow homogeneous free flowing powder
Gelling
Firm,comparable with 1.5% Agar gel
Colour and Clarity of prepared medium
Light yellow coloured, clear to slightly opalescent gel forms in Petri plates
Reaction
Reaction of 3.05% w/v aqueous solution at 25°C. pH : 8.3±0.2
pH
8.10-8.50
Cultural Response
Cultural characteristics was observed after an incubation at 35-37°C for 18-24 hours.
Organism Inoculum Growth Recovery Antibiotics
(CFU) assayed
Micrococcus luteus ATCC 50-100 luxuriant >=70% Erythromycin While assaying
9341 Tylosin,Tylosin, tartarate,
Vancomycin hydrochloride,
adjust the pH to8.0±.0.2
Staphylococcus aureus 50-100 luxuriant >=70% Kanamycin monosulphate,
ATCC 6538p (00195*) Kanamycin acid sulphate,
Netilmicin sulphate
Staphylococcus epidermidis 50-100 luxuriant >=70% Gentamicin, Neomycin,
ATCC 12228 (00036*) Netilmicin, Paromomycin,
Sisomycin
Bacillus pumilis ATCC 50-100 luxuriant >=70% Chlortetracycline ,Framycetin,
14884 Kanamycin sulphate
Bacillus subtilis subsp. 50-100 luxuriant >=70% Dihydrostreptomycin sulphate,
spizizenii ATCC 6633 Erythromycin estolate,Kanamycin
(00003*) monosulphate, Kanamycin
acid
Bacillus subtilis NCTC 50-100 luxuriant >=70% Dihydrostreptomycin sulphate,
8236 Streptomycin sulphate
Bacillus subtilis NCTC 50-100 luxuriant >=70% Erythromycin estolate,
8241 Gentamicin sulphate
Please refer disclaimer Overleaf.
HiMedia Laboratories Technical Data
*- Corresponding WDCM Numbers
Storage and Shelf Life
Store between 10-30°C in a tightly closed container and use freshly prepared medium. Use before expiry date on the label.
On opening, product should be properly stored dry, after tightly capping the bottle in-order to prevent lump formation due to
the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated
area protected from extremes of temperature and sources of ignition. Seal the container tightly after use.
Product performance is best if used within stated expiry period.
Disposal
User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow
established laboratory procedures in disposing of infectious materials and material that comes into contact with sample must
be decontaminated and disposed of in accordance with current laboratory techniques (5,6).
Reference
1. Grove and Randall, 1955, Assay Methods of Antibiotics Medical Encyclopedia, Inc, New York.
2. Schmidt and Moyer, 1944; J. Bact, 47:199.
3. The United States Pharmacopoeia-National Formulatory (USP-NF), 2022.
4. Tests and Methods of Assay of Antibiotics and Antibiotic containing Drugs, FDA, CFR, 1983. Title 21, part 436, Subpart
D, Washington, D.C. U.S Government printing office, paragraphs 436, 100-436, 106 pg 242-259 (April 1).
5. Isenberg, H.D. Clinical Microbiology Procedures Handbook 2nd Edition.
6. Jorgensen, J.H., Pfaller, M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W. (2015) Manual of
Clinical Microbiology, 11th Edition. Vol. 1.
Revision : 03/2023
Disclaimer :
User must ensure suitability of the product(s) in their application prior to use. Products conform solely to the information contained in this and
other related HiMedia™ publications. The information contained in this publication is based on our research and development work and is to the best
of our knowledge true and accurate. HiMedia™ Laboratories Pvt Ltd reserves the right to make changes to specifications and information related
to the products at any time. Products are not intended for human or animal or therapeutic use but for laboratory,diagnostic, research or further
manufacturing use only, unless otherwise specified. Statements contained herein should not be considered as a warranty of any kind, expressed or
implied, and no liability is accepted for infringement of any patents.
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