Pale Straw

//Pale Straw
  • Brilliant green agar is for the selective isolation of Salmonella spp., other than S. typhi. Brilliant green agar was first cited by Kristensen et al. in 1925 but was subsequently modified by the Netherlands Institute for Public Health. Brilliant green agar is generally used in conjunction with XLD agar (KM0013) as a secondary plating medium for subculture from selective enrichment media in food and environmental testing. It should be noted that the medium is highly selective and therefore not suited to the isolation of Salmonella spp. from samples where the numbers may be low. Beef extract, peptone and yeast extract provide the required carbon, nitrogen and vitamins. Di-sodium hydrogen phosphate and sodium di-hydrogen phosphate are buffering agents. Lactose and sucrose are fermentable carbohydrates. Phenol red is a pH indicator and turns the medium yellow during lactose and/or sucrose fermentation. Brilliant green inhibits Gram-positive bacteria and Gram-negative bacilli other than Salmonella spp. NB: It is not recommended that this medium be used for the isolation of Salmonella typhi or Shigella spp. Related Supplements : LS0024 Novobiocin Supplement (20mgs/L)
  • Formulated to ISO 6579, Buffered Peptone Water (BPW) is a pre-enrichment medium designed to help sub-lethally damaged Salmonella spp. recover before introducing them into a selective enrichment medium. Enzymatic digest of casein is the source of the required nitrogen, carbon and vitamins. Sodium chloride maintains the osmotic balance in the medium. Di-sodium hydrogen phosphate and potassium di-hydrogen phosphate act as buffers in the medium. This nutritious medium is free from inhibitors and is well buffered to maintain pH 7.0 for the incubation period. Sub-lethal injury to Salmonella spp. occurs in many food processes and this pre-enrichment step greatly increases the chance of their recovery, especially if a low number of cells are present in a sample.  
  • Cetrimide agar is a selective medium for the isolation and detection of Pseudomonas aeruginosa from pharmaceutical, clinical and cosmetic samples. The formulation is complaint with the requirements of the Harmonised USP/EP/JP. Detection is achieved using the unique ability of P. aeruginosa to produce the water soluble, bright green pigment pyocyanin. The production of this pigment is stimulated by the presence of magnesium chloride and di-potassium sulphate in the medium. The addition of glycerol (10ml/l) is required as this compound serves as an energy source. Cetrimide, a quaternary ammonium compound, is also present to suppress the growth of other Pseudomonas spp. as well as Gram-negative and Gram-positive organisms. Pancreatic digest of gelatin provides the required nitrogen, carbon and vitamins. Related Supplements :
  • KM0005

    CLED DI Agar

    Bevis modified Mackey and Sandy’s original medium by introducing a double indicator to improve the differentiation of lactose and non-lactose fermenting coliforms, staphylococci and streptococci spp. Cystine Lactose Electrolyte Deficient Double Indicator (CLED DI) is popular for urine culture in the clinical laboratory. The reduced number of electrolytes prevents swarming of Proteus spp. The peptone and beef extract is the source of the required nitrogen, carbon and vitamins. Lactose is a carbohydrate. The inclusion of bromothymol blue and Andrade’s as indicators allows easy differentiation of lactose and non-lactose fermenting organisms. L-Cystine is also present to benefit those organisms that have a particular cystine requirement. Streptococcus pyogenes and many other fastidious organisms that do not require the presence of blood can grow on this medium.  
  • KM0004

    CLED SI Agar

    CLED SI Agar Cystine Lactose Electrolyte Deficient Single Indicator (CLED SI) Agar is based on Mackey and Sandy’s formulation and is popular for culturing urine specimens in the clinical laboratory. The reduced number of electrolyte level prevents swarming of Proteus spp. The peptone and beef extract is the source of the required nitrogen, carbon and vitamins. Lactose is a carbohydrate. The inclusion of bromothymol blue as a pH indicator allows easy differentiation of lactose and non-lactose fermenting organisms. L-Cystine is also present to benefit those organisms that have a particular cystine requirement.  
  • KM0016

    GC Agar

    GC Agar when used with blood and other enrichment is for the isolation of Neisseria gonorrhoeae but is also capable of supporting the growth of most fastidious micro-organisms. This medium is based on the modified formulation described by Thayer and Martin that was based on the original formulation stated by Johnson. Enrichment is usually attained using lysed blood but haemoglobin powder or chocolated blood are suitable alternatives. Additional enrichment can be provided by the addition of Suplex supplement (BM0478) which consists of yeast extract and glucose. Selective variants of GC Agar can be prepared through the addition of various selective supplements such as VCAT (LS0002) or LCAT (LS0001). These supplements will suppress most of the background flora likely to be present in specimen and will restrict the swarming of Proteus spp. The peptone is the source of the required nitrogen, carbon and vitamins. Sodium chloride maintains the osmotic balance in the medium. Starch is present to absorb toxic metabolites and phosphate buffers prevent pH changes during incubation. Related Supplements : BM0478 Suplex, LS0001 GC LCAT Selective Supplement, LS0002 GC VCAT Selective Supplement
  • Approved by the Clinical & Laboratory Standards Institute (CLSI formerly known as the NCCLS) in USA this medium can be considered as an alternative to Iso-Sensitest Broth for antimicrobial sensitivity testing and MIC determinations by tube dilution methods. (1&2) Beef extract and acid hydrolysate of casein provides the required nitrogen, carbon and vitamins in the medium. Starch absorbs any toxic metabolites produced. References (1) Clinical and Laboratory Standards Institute. 2006. Performance standards for antimicrobial disk susceptibility tests. Approved standard M2-A9. CLSI, Wayne, PA. (2) MacFaddin, J. 1985. Media for isolation cultivation, identification maintenance of medical bacteria. Williams & Williams, Baltimore.
  • Pasteurella Agar Base is an non-selective medium capable of supporting the growth of Pasteurella spp. Pasteurella spp.are spherical, ovoid or rod-shaped cells 0.3-1.0μm in diameter and 1.0-2.0μm in length. Cells are Gram negative, and occur singly, or in pairs or short chains. Bipolar staining may be seen and capsules may be present. All species are non-motile, and are facultatively anaerobic.(1) With further enrichment using 5-10% blood and selective antimicrobials, most Pasteurella spp. can be isolated. There is no haemolysis on blood agar for Pasteurella spp. and the organism will not regularly exhibit satellitism around colonies of Staphylococcus spp. The peptones act as carbon, nitrogen and vitamin sources in this medium. Sodium chloride maintains the osmotic balance and the agar is a solidifying agent. The medium is made selective through the addition of LS0057, Pasteurella agar selective supplement. REFERENCE (1) Standards Unit, Microbiology Services, PHE. 1995. UK Standards for Microbiology Investigations. Identification of Pasteurella species and Morphologically Similar Organisms. 3, 1-28.
  • Sorbitol MacConkey agar is a differential medium for the isolation of Escherichia coli 0157:H7 based on the formulation by Rappaport and Henig. It differs from other MacConkey mediums in that lactose has been replaced by sorbitol. As Escherichia coli 0157:H7 does not ferment sorbitol it produces pale translucent colonies whereas most other strains of Escherichia coli are sorbitol positive and produce pink colonies. Although it should be noted that colonies that are sorbitol positive can revert and possibly be mistaken as sorbitol negative. Tryptone and meat peptone provide the required carbon, nitrogen and vitamins. Sorbitol is a fermentable carbohydrate and neutral red is a pH indicator. Bile Salts no.3 and crystal violet are selective agents and together inhibit Gram-positive cocci. Sodium chloride maintains the osmotic balance. If required, the selectivity of the medium may be increased by the addition of cefixime (0.05mg/L) and potassium tellurite (2.5mg/L). Related Supplements : LS0013 Escherichia coli 0157 Selective Supplement
  • Tryptone Soya Agar (TSA) is a general-purpose, non-selective medium capable of supporting the growth of most micro-organisms. This medium meets the requirements of the Harmonised USP/EP/JP and is based on the original formulation described by Leavitt et al. in 1955. TSA is commonly referred to as Soybean-Casein Digest Agar. TSA supplemented with lecithin and Tween 80® is widely used in environmental monitoring. With further enrichment using 5-10% sheep or horse blood, most fastidious organisms can be isolated and their haemolytic reactions can be determined in order to aid identification. It should be noted that the haemolytic patterns of isolates may vary with the source of animal blood and the type of basal medium used. The tryptone and soy peptone are the source of the required nitrogen, carbon and vitamins. Sodium chloride maintains the osmotic balance in the medium. Related Supplements : Defibrinated Sheep Blood, Defibrinated Horse Blood
  • A general purpose and nutritious medium for the non-selective enrichment of non-fastidious and some fastidious organisms. Tryptone and soy peptone are the nitrogen and vitamin source in the medium. Glucose is the carbon energy source that facilitates organism growth and sodium chloride maintains osmotic balance. Di-potassium hydrogen phosphate is a buffering agent to prevent auto-sterilisation due to acid production during the growth of some organisms. Tryptone Soya Broth is also commonly referred to as Soybean-Casein Digest Medium or Tryptic Soya Broth and is abbreviated as TSB. TSB conforms to the Harmonized United States Pharmacopoeia (USP), European Pharmacopoeia (EU), and Japanese Pharmacopoeia (JP).  
  • Xylose Lysine Deoxycholate (XLD) agar is used for the isolation and detection of Salmonella and Shigella spp. Developed by Taylor, xylose lysine agar base was used for isolating and differentiating Gram-negative enteric bacilli. The addition of sodium thiosulfate, ferric ammonium citrate, and sodium deoxycholate created the more selective medium, XLD agar. This medium was found to be satisfactory for the isolation of Shigella and Providencia spp., as well as proving to be an effective differential media. The yeast extract is the source of the required nitrogen, carbon and vitamins. Lactose, sucrose and xylose are fermentable carbohydrates. Sodium deoxycholate, sodium thiosulphate and ferric ammonium citrate are selective agents. Phenol red acts as a pH indicator. Sodium chloride maintains the osmotic balance. Most enteric bacteria including Salmonella spp., can ferment xylose to produce acid. Shigella spp. are unable to do this and thus the colonies remain red. Once xylose has been completely utilized Salmonella spp. will decarboxylate lysine resulting in a pH increase to alkaline. Salmonella and Shigella spp. are differentiated as Salmonellae spp. are able to metabolise thiosulphate producing hydrogen sulphide resulting in colonies with black centres. Stool specimens or rectal swabs may be plated directly onto XLD agar. Selective enrichment broths, such as Selenite Broth or Tetrathionate Broth, may be used prior to streaking. For specific procedures refer to appropriate references.  
  • This is a selective medium for the isolation and enumeration of yeasts and moulds in dairy products. It is in according to a typical formulation of The International Organisation for Standardisation (ISO). Yeast extract acts as a source of nitrogen, carbon and vitamins in this medium. Glucose is a fermentable carbohydrate. Although the medium has a low pH it is made more selective by the inclusion of chloramphenicol, an antibiotic selective agent.