Microbiology

• Oxoid Listeria Selective Oxford Agar Base is a selective and diagnostic medium for the detection of Listeria monocytogenes.
• Also available Listeria Selective Supplement, Part No. SR0140E and Modified Listeria Selective Supplement, Part No. SR0206E or SR0206B.

Listeria Selective Oxford Agar Base, Oxoid Composition

Listeria Selective Oxford Agar, Oxoid Preparation:
Suspend 27.75 of the Listeria Selective Agar Base (Oxford Formulation) in 500ml of distilled water. Bring gently to the boil to dissolve. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C and aseptically add the contents of one vial of Listeria Selective Supplement (Oxford Formulation) or Modified Listeria Selective Supplement (Oxford) SR0206, SR0140 reconstituted with 5ml of 70% ethanol. Mix well and pour into sterile Petri dishes.

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 plates at 2-8°C in the dark.

Oxoid SS Agar Modified (Salmonella Shigella Agar Modified) is used for the isolation of Salmonella species and Shigella spp.

Salmonella Shigella Agar Modified, Oxoid Composition

Salmonella Shigella Agar Modified, Oxoid Preparation:
Suspend 57g in 1 litre of distilled water. Bring to the boil with frequent agitation, and allow to simmer gently to dissolve the agar. DO NOT AUTOCLAVE. Cool to about 50°C mix well and pour into sterile Petri dishes.

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.

• Oxoid Listeria Enrichment Broth is used for the enrichment of Listeria species.
• Also available Listeria Selective Supplement, Part No. SR0140E or SR0141E and Modified Listeria Selective Enrichment Supplement, Part No. SR0206E or SR0206B.

Listeria Enrichment Broth Base, Oxoid Composition

Listeria Enrichment Broth, Oxoid Preparation:
Suspend 18g in 500ml of distilled water. Add the contents of one vial of Listeria Selective Enrichment Supplement (SR0141), reconstituted with 2ml of distilled water. Sterilize by autoclaving at 121°C for 15 minutes. Cool to 50°C, mix well and distribute into sterile containers in volumes as required.

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.

Precautions
Note the precautions stated under Listeria Selective Medium (Oxford) CM0856 and SR0140. Broth cultures are more dangerous than colonies on agar plates.
Store prepared medium away from light. Acriflavine can photo-oxidise to form inhibitory compounds against Listeria.
Supplement SR0141 used in this medium contains a toxic concentration of cycloheximide. Note the precautions to be taken under HAZARDS.

Oxoid Tergitol 7 Agar is used for the enumeration and identification of coliforms.

Tergitol 7 Agar, Oxoid Composition

TTC Solution (SR0148) is supplied as 2ml of filtered 0.125% aqueous solution of tri-phenyltetrazolium chloride (TTC).

Tergitol 7 Agar, Oxoid Preparation:
Suspend 54.15g in 1 litre of distilled water. Bring to the boil to dissolve completely. Dispense in 100ml volumes and sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C and add the contents of 1 vial of SR0148. Mix well and pour into sterile Petri dishes.

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.

Precautions
Tergitol-7 Agar is designed for early detection of Escherichia coli i.e. 6-10 hours incubation.
Incubation at 44°C has been recommended.

• Oxoid Listeria Selective Supplement (Oxford) is used for the detection of Listeria monocytogenes.
• Add to Listeria Selective Agar Base, Part No. CM0856B.

Listeria Selective Supplement (Oxford), Oxoid Composition

Listeria Selective Medium Preparation:
Reconstitute one vial as directed, aseptically add the contents to 500 ml of Listeria Selective Agar Base (Oxford Formulation) CM0856, cooled to approximately 50°C. Mix well and pour into sterile Petri dishes.

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 plates at 2-8°C in the dark.

Oxoid LCAT Selective Supplement is used for the preparation of New York City Medium for the isolation of Neisseria spp.

• Add to GC Agar Base, Part No. CM0367B
• Each vial supplements 500mL of medium

LCAT Selective Supplement, Oxoid Composition

LCAT Selective Medium Preparation:
Reconstitute one vial as directed, aseptically add the contents to 490ml of sterile GC Agar Base CM0367, cooled to approximately 50°C, containing 50 ml Laked Horse Blood SR0048 and the rehydrated contents of one vial of Yeast Autolysate Supplement SR0105. Mix gently and pour into sterile Petri dishes.

Detect and enumerate enterococci from water and food samples with Thermo Scientific™ Slanetz and Bartley Medium (Dehydrated). Slanetz and Bartley originally devised this medium to detect and enumerate enterococci by the technique of membrane filtration, but it has also proved useful as a direct plating medium. The medium is very selective for enterococci and, when it is incubated at elevated temperatures (44-45°C), all red or maroon colonies may be accepted as presumptive enterococci.

Slanetz and Bartley Medium (Dehydrated), Oxoid Composition

Slanetz and Bartley Medium Preparation:
Suspend 42g in 1 litre of distilled water and bring to the boil to dissolve the agar completely.

EXCESSIVE HEATING MUST BE AVOIDED. Dispense into Petri dishes and allow to solidify. It should not be remelted. The medium may be used with membrane filters or by spreading dilutions of the sample over the surface of the agar with a glass rod.

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 away from light.

Precautions
Count all red, maroon or pink colonies as presumptive enterococci. Not all species reduce TTC therefore pale colonies should not be ignored.
Although incubation at 35°C yields a higher count, it allows the growth of organisms which do not conform to the definition of enterococci. Incubation at 44-45°C has a selective effect and produces fewer false-positives. However, the preliminary incubation at 35°C encourages the recovery of stressed organisms.
Although the selective properties of this medium are very good it is advisable to regard the colony count as a presumptive or unconfirmed count. Further identification may be required depending on the scope of the examination.

Oxoid MRSV Selective Supplement is used for the detection of Salmonella spp. from food and environmental samples.

• Add to MSRV Medium Base, Part No. CM0910B and Lysine Iron Agar, Modified (MLIA), Part No. CM0886B
• Each vial supplements 500mL of medium

MRSV Selective Supplement, Oxoid Composition

MSRV Medium, Oxoid Preparation:
Suspend 15.8g of MSRV Medium Base in 500ml of distilled water. Bring to the boil with frequent agitation.
DO NOT AUTOCLAVE. Cool to 50°C and aseptically add the contents of 1 vial of MSRV Selective Supplement SR0161E reconstituted with 2ml of sterile distilled water. Mix well and pour into sterile Petri dishes. Air dry at room temperature for at least one hour. (Plates may be air-dried overnight prior to storage at 2-8°C.)

Storage conditions and Shelf life
Store the selective supplement in the dark at 2-8°C and use before the expiry date on the label.
The prepared medium may be stored for up to 2 weeks at 2-8°C away from the light.

A modified medium requiring the addition of basic fuchsin to form Endo Agar.

• Oxoid Endo Agar is an APHA recommended medium for the confirmation of coliforms.
• Also available Basic Fuchsin Indicator, Part No. BR0050A.

Endo Agar Base, Oxoid Composition

Endo Agar, Oxoid Preparation:
Suspend 36g in 1 litre of distilled water. Add 6ml (or as directed by the supplier) of a 10% w/v solution of basic fuchsin BR0050 (50:50 ethanol/distilled water). Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Mix well before pouring. Plates should be stored in the dark to preserve their pale pink colour.

BASIC FUCHSIN IS A POTENTIAL CARCINOGEN AND CARE SHOULD BE TAKEN TO AVOID INHALATION OF THE POWDERED DYE AND CONTAMINATION OF THE SKIN.

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 plates at 2-8°C away from light.

Precautions
Weigh out the basic fuchsin (BR0050) in a fume cupboard and avoid inhalation of the powder or contamination of the skin.
Keep the prepared medium away from light to avoid photo-oxidation.
Endo Agar is quoted by the American Public Health Association as a `Standard Methods’ medium for use in water¹ and dairy products. Windle Taylor recommended the medium for the isolation and differentiation of coli-aerogenes bacteria from water.

Selectively isolate and presumptively identify Clostridium perfringens in food samples with Thermo Scientific™ Oxoid™ Perfringens TSC Agar Base (Dehydrated). The medium can either be used on its own or with selective agents to make Tryptose Sulphite (TS) Agar, Tryptose Sulphite Cycloserine (TSC) agar or Shahadi Ferguson Perfringens (SPF) agar for the presumptive identification and enumeration of Clostridium perfringens.

Perfringens TSC/SFP Agar Base, Oxoid Composition

Agar Preparation:
To Prepare the Agar Base:
Suspend 23g in 500ml of distilled water and heat gently until the agar is completely dissolved. Sterilise by autoclaving at 121°C for 10 minutes. Allow the medium to cool to 50°C.

To Prepare Tryptose Sulphite Cycloserine Agar (TSC Agar):
To 500ml of Agar base cooled to 50°C add the rehydrated contents of 1 vial of TSC supplement (SR0088) and 25ml of egg yolk emulsion (SR0047). Mix well and pour into sterile Petri dishes.

To Prepare Egg Yolk Free TSC Agar:
To 500 ml of Agar base cooled to 50°C add the rehydrated contents of 1 vial of TSC supplement (SR0088). Mix well and pour into sterile Petri dishes.

To Prepare Shahidi-Ferguson Perfringens Agar (SFP Agar):
To 500 ml of Agar base cooled to 50°C add the rehydrated contents of 1 vial of SFP supplement (SR0093) and 25ml of egg yolk emulsion (SR0047) mix well and pour into sterile Petri dishes.

To Prepare Agar for an Overlay:
For TSC or SFP Agar used as an overlay, the egg yolk emulsion (SR0047) is omitted. Its inclusion does not improve the lecithinase reaction and diminishes the visibility of the colonies.

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.

Precautions
Black colonies appearing on these two media may be organisms other than Clostridium perfringens.

Oxoid Peptone Special is a specifically prepared mixture of peptones designed to encourage growth of the most fastidious microorganisms.

• Oxoid Listeria Selective Supplement (Oxford) is used for the detection of Listeria monocytogenes.
• Add to Listeria Selective Agar Base, Part No. CM0856B.

Modified Listeria Selective Supplement (Oxford), Oxoid Composition

Modified Listeria Selective Medium Preparation:
Reconstitute one vial as directed, aseptically add the contents to500 ml of sterilised Listeria Selective Agar Base (Oxford Formulation) CM0856, cooled to approximately 50°C. Mix well and pour into sterile Petri dishes.

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 plates at 2-8°C in the dark.

• Oxoid Bordetella Selective Supplement (Cephalexin, 20mg/vial) is used for the selective isolation of Bordetella pertussis and B. parapertussis.
• Add to Charcoal Agar Base, Part No. CM0119B. Each vial supplements 500mL of medium.

Bordetella Selective Supplement, Oxoid Composition

Bordetella Selective Medium, Oxoid Preparation:
Aseptically add 2ml of sterile distilled water to one vial and mix gently to dissolve the contents completely. Aseptically add the contents to 500ml of sterile molten Charcoal Agar CM0119, cooled to approximately 50°C, together with 10% defibrinated horse blood SR0050 . Mix well and pour into sterile Petri dishes.
The vial contents may also be added to half strength Charcoal Agar CM0119 plus 10% defibrinated horse blood SR0050, for use as a transport medium for Bordetella pertussis.

Oxoid Desoxycholate Citrate Agar is a differential medium for enumeration of coliforms and the isolation of enteric pathogens.

Desoxycholate Citrate Agar, Oxoid Composition

Desoxycholate Citrate Agar, Oxoid Preparation:
Suspend 48.5g in 1 litre of distilled water. With frequent agitation bring to the boil over a gauze and flame to dissolve completely. Mix well and pour plates immediately. Dry the agar surface before use.

THIS MEDIUM IS HEAT SENSITIVE. AVOID EXCESSIVE OR PROLONGED HEATING DURING RECONSTITUTION. DO NOT AUTOCLAVE, OR REMELT.

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.

Precautions
The medium is best used freshly prepared.
Stock cultures of Shigella species may become predominantly in the R-phase when subcultured away from DCA media. Such cultures are difficult to use for control purposes without first heavily streaking the cultures on DCA plates and picking off the few S-phase colonies i.e. the macro-colonies on the agar surface, for further subculture.
When making biochemical tests on colonies picked from the surface of DCA plates, purity subcultures should be carried out because the colony may be contaminated with Escherichia coli present as micro-colonies.

Isolate Burkholderia cepacia from respiratory secretions of patients with cystic fibrosis with Thermo Scientific™ Oxoid™ Burkholderia Cepacia Agar Base, which is also used for routine testing of non-sterile inorganic salt solutions in hospital environments. The slower growing B. cepacia can be missed on conventional media, such as blood or MacConkey Agar, due to overgrowth caused by other faster growing organisms found in the respiratory tract of CF patients, such as mucoid Klebsiella species,
Pseudomonas aeruginosa and Staphylococcus species.This may lead to the infection being missed or wrongly diagnosed.

Burkholderia Cepacia Agar Base, Oxoid Composition

Burkholderia Cepacia Agar, Oxoid Preparation:
Suspend 18.25g of Burkholderia cepacia Agar Base in 500ml of distilled water, mix well and sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C and aseptically add the contents of one vial of Burkholderia cepacia Selective Supplement SR0189, reconstituted as directed. Mix well and distribute into sterile Petri dishes.

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 plates of medium at 2-8°C.

Isolate, enumerate, and identify coagulase positive Staphylococcus aureus in food samples with selective Thermo Scientific™ Oxoid™ Baird Parker Agar (ISO) Base (Dehydrated) while adhering to ISO 6888-1:1999.

Baird Parker Agar (ISO) Base, Oxoid Composition

Baird Parker Agar (ISO) Base, Oxoid Preparation:
Suspend 63g of Baird-Parker Agar (ISO) Base in 1,000ml of distilled water. Boil to dissolve the medium and sterilise by autoclaving at 121°C for 15 minutes. Cool to 47°C and aseptically add 50ml of Egg Yolk Tellurite Emulsion (SR0054). Mix well and pour into sterile Petri dishes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
The prepared medium is best used freshly prepared, but may be suitable for longer storage following in-house validation.

Precautions
Atypical colonies have the same size as typical colonies but can be shining black with or without a narrow white edge; the clear zone or opacity halo can also be absent or barely visible. Grey colonies, free of clear zone, can also be regarded as atypical.
Regard all typical and atypical colonies as coagulase-positive staphylococci irrespective of negative reactions on the medium and carry out further tests.
Colonies of some contaminating organisms growing in close proximity to the coagulase positive colonies may partially digest the coagulase halo reaction.

• Oxoid Haemophilus Test Medium Base (HTM) is used for the susceptibility testing of Haemophilus influenzae.
• Also available HTM Supplement, Part No. SR0158E. Store at -20° to 0°C.

Haemophilus Test Medium Base (HTM), Oxoid Composition

Haemophilus Test Medium (HTM), Oxoid Preparation:
Suspend 21.5g of Haemophilus Test Medium Base in 500ml of distilled water. Bring to the boil to dissolve. Sterilise by autoclaving at 121° C for 15 minutes. Cool to 50°C and aseptically add the contents of 1 vial of Haemophilus Test Medium Supplement SR0158, as directed. Mix well and pour into sterile Petri dishes.

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 plates of medium at 2-8°C.
When stored as directed the supplement is stable until the expiry date stated on the label.

Isolate Salmonella typhi and other salmonllae from pathological material, sewage water supplies, food and other products with Thermo Scientific™ Oxoid™ Bismuth Sulphite Agar (Modified Wilson & Blair Medium) (Dehydrated). Bismuth Sulphite Agar is a modification of the original Wilson and Blair Medium and is particularly useful for the isolation of lactose-fermenting salmonellae. The presence of bismuth sulphite and brilliant green make this medium highly selective for salmonellae.

Bismuth Sulphite Agar, Oxoid Composition

Bismuth Sulphite Agar, Oxoid Preparation:
Suspend 20g in 500ml of distilled water in a 1 litre flask. Heat gently with frequent agitation until the medium just begins to boil and simmer for 30 seconds to dissolve the agar. Cool to 50-55°C, mix well to disperse suspension and pour thick plates (25 ml medium per plate). Allow the medium to solidify with the dish uncovered. Larger volumes may be prepared if great care is taken and adequate head space provided.
Dry the plates before use but take care to avoid overdrying. Correctly prepared plates should have a smooth, cream-like opacity with a pale straw colour. There should be no sedimentation of the indicator.
DO NOT OVERHEAT – DO NOT AUTOCLAVE

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label. Note the following comments:
Due to its contents of reactive and hygroscopic substances, dehydrated Bismuth Sulphite Agar quickly deteriorates when exposed to the atmosphere. This is usually indicated by aggregation into a solid non-friable mass, and by the development of a brown coloration. Medium reconstituted from such material is brown, does not become green on storage, and is characterised by loss of differential and selective properties. For this reason the powder should be stored in a cool, dry place and after use the container should be properly closed.

Precautions
Prepared plates of medium should not be stored for longer than two days at 2-8°C; after which time the dye oxidises to give a green medium that can be inhibitory to some salmonellae.

Shigella species are usually completely inhibited.

Salmonella sendai, Salmonella cholera-suis, Salmonella berta, Salmonella gallinarum and Salmonella abortus-equi are markedly inhibited.
It is important that the spreading technique yields well separated colonies. The typical colonial characteristics will not develop if the growth is too heavy or confluent; Salmonella typhi colonies will appear light green in these circumstances. Therefore, when in doubt, almost any growth on the medium should be subject to further tests.

Thermo Scientific™ Oxoid Vancomycin Supplement is for addition to selective media for the isolation of Vancomycin Resistant Enterococci (VRE) and High Level Aminoglycoside Resistant Enterococci (HLARE) from clinical specimens.

• Each vial supplements 500mL of medium

Vancomycin Supplement, Oxoid Composition

Cronobacter Screening Broth (CSB), Oxoid Preparation:
Dissolve 14.02g in 500ml of distilled water. Sterilize by autoclaving at 121°C for 15 minutes. Cool to approximately 50°C, and aseptically add the contents of 1 vial of Vancomycin Supplement (5mg) (SR0247E) reconstituted as directed. Mix well and aseptically dispense into sterile containers.

Modified Lauryl Sulphate Tryptose Broth, Oxoid Preparation:
Dissolve 32.3g in 500ml of distilled water. Sterilize by autoclaving at 121°C for 15 minutes. Cool to approximately 50°C, and aseptically add the contents of 1 vial of Vancomycin Supplement (5mg) (SR0247E) reconstituted as directed. Mix well and aseptically dispense into sterile containers.

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

Oxoid Proteose Peptone is a speciality peptone containing proteoses as defined in the USP.

• Particularly suitable for use in toxin production and in culture media for bacteria with wide-ranging nutritional requirements

• Oxoid Sorbitol MacConkey Agar is a selective differential medium for the detection of E. coli O157.
• Also available C-T Supplement, Part No. SR0172E and SR0172H.

Sorbitol MacConkey Agar Base, Oxoid Composition

Sorbitol MacConkey Agar, Oxoid Preparation:
Suspend 51.5g in 1 litre of distilled water. Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Allow to cool to 50°C. Pour into sterile Petri dishes.

If required, reconstitute one vial of C-T supplement per 500ml medium, according to the instructions in the product leaflet. Aseptically add this to cooled medium before pouring into sterile Petri dishes

Storage conditions and Shelf life
Dehydrated Sorbitol MaConkey Agar must be stored tightly capped in the original container at 10-30ºC.

Oxoid Sorbitol MacConkey and Cefixime Tellurite Sorbitol MacConkey plates should be stored in the original packaging, at the temperature stated on the pack or product specification, and protected from direct light. When stored as directed, the unopened product will remain stable until the expiry date on the label.

Locally prepared media can be stored for up to 2 weeks when made from CM0813 and SR0172 according to the manufacturer’s instructions and stored at 2-8ºC, out of direct sunlight and protected from dessication. A longer shelf life may be attainable, but should be validated under the relevant, local manufacturing and storage conditions.