Dehydrated Culture Media

  • This is one of several selective media available for the isolation of Campylobacter spp. in clinical, food and environmental laboratories. Campylobacter agar base is based on the formulation from Bolton and Robertson. The peptone is the source of the required nitrogen, carbon and vitamins. Sodium chloride maintains the osmotic balance in the medium. The medium is enriched with lysed horse blood and made selective by the addition of cefoperazone, to suppress other enteric organisms, and amphotericin to suppress yeast and fungal growth (Preston supplement LS0010). Related Supplements : LS0009 Campylobacter (Skirrow) Selective Supplement, LS0010 Campylobacter (Preston) Selective Supplement, Lysed Blood
  • Campylobacter Blood-Free Selective Medium (CCDA) is one of several media formulations available for the selective isolation of Campylobacter spp., primarily C. jejuni and C. coli. CCDA was described by Bolton et al. and formulated to replace blood with a combination of charcoal, ferrous sulphate, and sodium pyruvate. CCDA is recommended for food testing. CCDA with the addition of yeast extract and cefoperazone is used in the isolation of Campylobacter spp. from foodstuffs and swabs in the FDA/BAM method. This product complies with the requirements of ISO 10272-1:2006. Bolton et al. recommended incubating inoculated plates at 37°C to improve isolation rates but incubation at 41.5°C is recommended for the isolation of the commonly encountered thermophilic species (C. jejuni and C. coli). The meat peptone, beef extract and tryptone provide the required nitrogen, carbon and vitamins. Bacteriological charcoal absorbs toxic compounds and metabolites. Ferrous sulphate and sodium pyruvate are oxygen scavengers. Sodium desoxycholate is a selective agent. Through the addition of campylobacter (Preston) supplement (LS0010), which consists of cefoperazone and amphotericin B, enteric flora is suppressed. Related Supplements : LS0010 Campylobacter (Preston) Selective Supplement
  • KM0052

    CEMO Agar

    This medium is based on the formulation published by Platt, Atherton & Simpson1 and is used for the cultivation of Taylorella equigenitalis, the causative organism in contagious equine metritis. It is routinely used for culturing swabs taken from the genitalia of mares and stallions. Enzymatic digest of casein and soy peptone supply nitrogen, carbon and vitamins and L-cystine is a required growth factor. Sodium chloride provides osmotic balance and sodium sulphite is present as a reducing agent. The medium is made selective by the addition of CEMO Selective Supplement (LS0041) to control bacteria and fungi from swab samples. References 1. Platt, H., Atherton, J. G. and Simpson, D. J. 1978. Equine Vet J 10, 153–159.
  • 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 :
  • KM0185

    Charcoal Agar

    Charcoal agar is used for the cultivation of fastidious organisms, particularly Bordetella pertussis. Charcoal agar is prepared according to the formulation developed by Mishulow, Sharpe and Cohen. This medium is an efficient substitute for Bordet-Gengou agar in the production of B. pertussis vaccines and can be used as a maintenance medium for stock cultures of Bordetella spp. Beef extract and peptone provide the required nitrogen, carbon and vitamins. Sodium chloride maintains the osmotic balance. Starch and charcoal help in absorbing toxic metabolites that are produced during growth of the organism. Nicotinic acid is an essential growth factor for the growth of Bordetella spp. The addition of cephalexin (LS0018) inhibits accompanying contamination in the samples. NB: This is a basic medium only and contains no additional supplement. If cephalexin is added, it should be noted, that although coliforms are inhibited by this medium, Pseudomonas aeruginosa and some fungi will grow. Related Supplements : LS0018 Bordetella Selective Supplement
  • Chromogenic coliform agar (CCA) conforms to the ISO 9308-1 guidelines for the detection, enumeration and isolation of coliforms and more specifically Escherichia coli in water samples by the membrane-filtration technique. The colonial differentiation is provided by the chromogenic substrates, Salmon-GAL and X-glucuronide. Salmon-GAL is used for the detection of ß-D-galactosidase enzymatic activity. X-glucuronide is used for the detection of ß-D-glucoronidase enzymatic activity. β-D-galactosidase, expressed by all coliforms, cleaves the Salmon-GAL substrate and producing red/pink coloured colonies. Unlike other coliforms, Escherichia coli cleaves both Salmon-GAL and X-glucuronide producing a violet/blue coloured colonies. Tryptophan is used to increase detection reliability by improving the indole reaction. The peptones, sodium pyruvate and sorbitol support bacterial growth and simple recovery of sub-lethal thermally injured coliforms. Sodium di-hydrogen phosphate and di-sodium hydrogen phosphate phosphate buffer the medium and sodium chloride is used to achieve osmotic balance. The selectivity is attained by the addition of Tergitol® 7 as it inhibits the growth of Gram-positive bacteria.
  • 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.  
  • Clostridium difficile agar, when supplemented, is used for the isolation of C. difficile from samples. This formulation is a modification of CCFA (Cycloserine-Cefoxitin-Fructose agar) developed by George et al. The proteose peptone act as carbon, nitrogen and vitamin source in this medium. Fructose is a fermentable carbohydrate. Sodium chloride maintains the osmotic balance of the medium. Disodium hydrogen phosphate and potassium dihydrogen phosphate are buffering agents. The magnesium sulfate acts as a source of inorganic ions and the agar is the solidifying agent. This media requires the addition of defibrinated horse blood and Clostridium difficile selective supplement (LS0022).
  • KM0001

    Columbia Agar

    Columbia agar is a general-purpose, non-selective medium capable of supporting the growth of most micro-organisms based on the original Columbia agar formulation described by Ellner et al. from Columbia University. With further enrichment using blood, most fastidious organisms can be isolated and their β-haemolytic reactions can be determined in order to aid identification. The peptone is the source of the required nitrogen, carbon and vitamins. Starch increases growth of Neisseria spp., and enhances the haemolytic reactions of some streptococci. This medium is relatively free of reducing sugars, which have been reported to adversely influence the haemolytic reactions of β-haemolytic streptococci . Supplementation of the base medium with blood (5- 10%) will provide additional growth factors for fastidious microorganisms, and aids in determining haemolytic reactions. 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. Related Supplements : Defibrinated Horse Blood, Defibrinated Sheep Blood, Horse Blood Lysed, LS0008 Staph/Strep Selective Supplement, LS0017 Neomycin Selective Supplement, LS0022 Clostridium difficle Selective SupplementLS0012 Bacitracin Selective Supplement, LS0011 Campylobacter Growth Supplement, LS0009 Campylobacter (Skirrow) Selective Supplement
  • This medium is used for the cultivation and enumeration of Lactobacillus spp. MRS agar is based on the formulation by de Man, Rogosa and Sharpe. The peptone, yeast extract and beef extract provides the reuired carbon, nitrogen and vitamin source. Glucose is a fermentable carbohydrate. The magnesium sulphate and manganese sulphate act as growth stimulants. Potassium phosphate is a buffering agent. Selectivity of the medium is achieved through the use of ammonium citrate and sodium acetate, inhibiting microorganisms such as streptococci and moulds. The addition of the surfactant Tween 80 is required to facilitate the uptake of nutrients from Lactobacillus spp.  
  • This medium is intended for the cultivation and enumeration (via the Miles and Misra technique) of Lactobacillus spp. from a variety of sources and can be used in conjunction with MRS Agar (KM0080). This medium is a modification on the formulation developed by de Man, Rogosa and Sharpe.(1) The peptones, beef extract, yeast extract provides the required carbon, nitrogen and vitamins in this medium. Glucose is a fermentable carbohydrate. Potassium phosphate is a buffering agent. Selectivity of the medium is achieved through the use of ammonium citrate and sodium acetate, inhibiting microorganisms such as streptococci and moulds. The magnesium sulphate, manganese sulphate and polysorbate 80 act as growth stimulants. The medium can be made more specific for lactobacilli generally by lowering the pH to between 5.0 and 5.5. This has the effect of inhibiting most streptococci that may otherwise grow on the medium and can be readily confused with lactobacilli.
  • This is a selective medium for the isolation of Salmonella spp. and Shigella spp. from clinical specimens and environmental samples. This formulation was developed by Hynes through a modification of Leifson’s DCA medium. The peptone provides the required carbon, nitrogen and vitamins. Lactose is a fermentable carbohydrate and neutral red is a pH indicator. Sodium thiosulphate and ferric citrate are used to detect hydrogen sulphide production indicated by the black centred colonies of hydrogen sulphite positive organisms. Sodium desoxycholate and sodium citrate inhibit most Gram-positive organisms.
  • A selective medium for the isolation and detection of dermatophytic fungi originally developed by Taplin et al. Dermatophytes appear as fluffy colonies with reddening of the medium while other fungi cause the medium to become yellow due to acid production. Yeasts will also grow on this medium but are readily distinguished by their distinct white/creamy colonies and distinctive smell. Soy peptone provides the required carbon, nitrogen and vitamins. Glucose is a fermentable carbohydrate. The inclusion of phenol red assists in the differentiation between saprophytic and environmental fungi. Although the low pH (pH 5.5) of the medium inhibits most bacteria chloramphenicol and cycloheximide are often added to further reduce the risk when processing material that may be more heavily contaminated. NB: Prolonged incubation should be avoided as this may cause fungi other than dermatophytes to turn the medium red. Related Supplements : LS0050 Chloramphenicol Selective Supplement
  • Dichloran Rose Bengal Chloramphenicol (DRBC) agar is based on the formulation described by King et al. and is used for the selective isolation and enumeration of yeasts and moulds from food samples. The peptone provides the required carbon, nitrogen and vitamins. Glucose is a fermentable carbohydrate. Potassium di-hydrogen phosphate is a buffering agent and magnesium sulfate is a source of divalent ions and sulfate. In order to curtail the size of the colony diameters of spreading fungi, the antifungal agent dichloran is added to the base and the pH is reduced to 5.6. Rose Bengal suppresses growth of bacteria and restricts the size and height of colonies of more rapidly growing molds. The inclusion of chloramphenicol ensures the suppression of bacteria present in environmental and food samples. Rose Bengal is absorbed by yeast and mold colonies and this further aids in their enumeration. Occasionally reduced recovery of yeasts may be encountered due to the increased activity of Rose Bengal at pH 5.6.