诊断敏感实验琼脂
英文名称: Diagnostic Sensitivity Test Agar
型号:null    产品货号: CM0261B
价格:请致电:010-57128832,18610462672
品牌: 英国

DIAGNOSTIC SENSITIVITY TEST AGAR (DST AGAR)

Code: CM0261

A susceptibility test agar for antimicrobial testing.

Typical Formula*

gm/litre

Proteose peptone

10.0

Veal infusion solids

10.0

Glucose

2.0

Sodium chloride

3.0

Disodium phosphate

2.0

Sodium acetate

1.0

Adenine sulphate

0.01

Guanine hydrochloride

0.01

Uracil

0.01

Xanthine

0.01

Aneurine

0.00002

Agar

12.0

pH 7.4 + 0.2 @ 25°C

 
* Adjusted as required to meet performance standards

Directions
Add 40 g to 1 litre of distilled water. Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes.
For blood agar, cool the base to 50°C and add 7% of Defibrinated Horse Blood SR0050. Mix with gentle rotation and pour into Petri dishes (12 ml for a 9 cm dish) or other containers.
RECONSTITUTION AND MIXING SHOULD BE PERFORMED IN A FLASK AT LEAST 2.5 TIMES THE VOLUME OF MEDIUM TO ENSURE ADEQUATE AERATION OF THE BLOOD.

Description
Diagnostic Sensitivity Test Agar was developed in Oxoid as a dual purpose medium which would satisfy both diagnostic and susceptibility requirements.

The diagnostic role was supported by the nutritional amino-acid base with glucose to encourage early growth. The inclusion of the buffers (disodium phosphate and sodium acetate) helped prevent excessive movements of pH values which could result from utilisation of glucose or amino-acids. Such pH movements would interfere with haemolytic reactions1 and the MIC values of pH-susceptible antimicrobials2.
Long before the mechanisms of folate antagonism had been discovered, the addition of the bases adenine, guanine, uracil and xanthine were shown to improve the performance of the medium as an antimicrobial test medium.

Aneurine, added as a general purpose vitamin, improved the growth of several organisms especially staphylococci.

The agar used in the formulation has been specially processed to allow unimpeded diffusion of antimicrobials from discs3.
DSTA is now primarily used for susceptibility tests and its role in diagnostic microbiology i.e. the primary isolation of organisms from clinical samples, has diminished.

An essential requirement for satisfactory antimicrobial susceptibility media is that the reactive levels of thymidine and thymine must be sufficiently reduced to avoid antagonism of trimethoprim and sulphonamides4.

DSTA meets this requirement and in the presence of lysed horse blood (or defibrinated horse blood if the plates are stored long enough to allow some lysis of the erythrocytes) the level of thymidine will be further reduced. This is caused by the action of the enzyme thymidine phosphorylase which is released from lysed horse erythrocytes5. Thymidine is an essential growth factor for thymidine-dependent organisms and they will not grow in its absence or they will grow poorly in media containing reduced levels6. It is important that users of DSTA are aware of this limitation of thymidine which now exists in the medium and the effect it will have on a small proportion of organisms.

Details of the function of the medium and the methodology used for antimicrobial susceptibility tests are discussed in the Section `Susceptibility Testing’.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared agar plates at 2-8°C.

Appearance
Dehydrated medium: Light straw coloured, free-flowing powder
Prepared medium: Straw coloured gel

Quality control

Positive controls:

Expected results

With blood 
Streptococcus pneumoniae ATCC® 6303 *

Good growth; grey/green mucoid colonies with alpha-haemolysis

Staphylococcus aureus ATCC® 25923 *

Good growth; white/grey coloured colonies

Without blood 
Enterococcus feacalis ATCC® 29212 *Good growth; straw colonies
Pseudomonas aeruginosa ATCC® 27853 *Good growth; straw colonies with green pigmentation

Negative control:

 

Uninoculated medium

No change

* This organism is available as a Culti-Loop®

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Micro-organism

Laked Blood (5% v/v)

Neisseria, Streptococcus

Fildes Peptic Digest of Blood (5% v/v)

Haemophilus

Menadione (0.5 mg/ml) Thiamine (2 mg/ml)

Dwarf colonies of Staphylococcus aureus and coliform organisms

Pyridoxine hydrochloride (1 mg/ml)

Symbiotic streptococci

Certain supplements interfere with antimicrobial activity and tests must be made to measure their effect.

Nutrient

Antimicrobial

Thymidine

Trimethoprim

Blood

Sulphonamides, trimethoprim, aminoglycosides

CO2

Aminoglycosides,erythromycin, lincomycin, tetracyline, novobiocin

Cysteine and other-SH compounds

Aminoglycosides                       

Vitox/Isovitalex Sulphonamides, trimethoprim

Iso-Sensitest Agar with the addition of 10% of horse blood has been recommended as a suitable medium when testing susceptibility of Helicobacter pylori21. Although Mueller-Hinton agar performed nearly as well, Iso-Sensitest Agar was preferred because its contents are better defined.

Iso-sensitest Agar is recommended by the BSAC for use within their Disc Diffusion Method for Antimicrobial Susceptibility Testing22.

Storage conditions and Shelf Life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8° C and use as freshly as possible.

Appearance
Dehydrated medium: Straw coloured, free-flowing powder
Prepared medium: Straw coloured gel

gcolor:#92B820" height="248" scrolling="no" frameborder="0">US" style="font-size: 10.5pt;">500ml*6

DMEM低糖培养基液体  常规型

CP2205

1L*5

DMEM高糖培养基粉末  常规型

CP2206

10L

CP2207

50L

CP2208

500ml*6

DMEM高糖培养基液体  常规型

CP2209

1L*5

DMEM高糖培养基粉末 不含丙***酸钠型

CP2210

10L

CP2211

50L

CP2212

500ml*6

DMEM高糖培养基液体 不含丙***酸钠型

如需更大规格,请咨询400-999-3832

 

保存温度: 2-8

有效期: 液体12 个月 干粉24个月

产品描述:Dulbeccos Modified Eagle Medium (DMEM)基本培养基,用于支撑许多不同的哺乳动物细胞的生长一种广泛使用的基础培养基。改良自Eagle基础培养基,添加了4倍浓度的氨基酸和维生素等营养物质,最初研制的DMEM 培养基是低糖的(1 g/L葡萄糖),而现在更常用的高糖培养基(4.5 g/L葡萄糖),高糖分更适合于低粘附性和增长快速的克隆细胞培养。在DMEM成功培养细胞包括成纤维细胞,神经细胞,神经胶质细胞,血管内皮细胞,以及平滑肌细胞,以及细胞系如HeLa细胞,293COS-7,和PC-12。近年DMEM还广泛应用在CHO/293等细胞表达蛋白等工业化生产上。

如你未能确认使用何种培养基,请与我们联系,需求技术支持。

 

干粉培养基配制

自备材料

新鲜制备三蒸水或注射级超纯水

碳酸氢钠

1 N 盐酸溶液(无菌)

1 N 氢氧化钠溶液(无菌)

与终体积接近的容器(无菌)

PH

滤器,0.22um滤膜