Burkholderia Cepacia Agar Base is a selective medium especially formulated for the isolation of Burkholderia cepacia (Pseudomonas cepacia), from clinical and non-clinical specimens. Burkholderia cepacia is a Gram-negative, oxidase positive, mobile and aerobic bacillus. It is normally found in water deposits and damp environments. This bacillus is an important opportunist pathogen and causes pulmonary infections in Cystic Fibrosis patients. The organism may be present in small numbers in many non sterile products used in hospitals. It has been isolated from a number of water sources and can grow in distilled water with a nitrogen source because of its capacity to fix CO2 from air. Suction catheters rinsed in a solution of acetic acid have reduced the transmission of Burkholderia cepacia and other Pseudomonas. The medium contains peptone, which provides nitrogen, vitamins, minerals and amino acids essential for growth. Selective agents are added to improve B. cepacia recovery through the inihibition of common contaminants. Crystal violet inhibits Gram-positive cocci, especially enterococci and staphylococci. Bile salts inhibit most Gram-positive cocci except for enterococci, and ticarcillin and polymyxin B inhibit Gram-negative bacilli. Phenol red facilitates detection of B. cepacia. Alkaline end products from the metabolism of pyruvate raise the pH of the medium, causing the color of the indicator to change from light orange to pink, or pink-red, in the growth area. In areas of heavy B. cepacia growth, the pink color intensifies. Magnesium sulphate, ammonium sulphate and ferrous sulfate provide sources of sulfates and metallic ions. Phosphate salts act as a buffer system. Bacteriological agar is the solidifying agent. Colonies of B. cepacia are 1-2 mm in diameter and turn the medium to pink. Low numbers of colonies may not produce a color change of the medium. Occasional growth of some strains of Candida species, Stenotrophomonas maltophilia, Pseudomonas aeruginosa and other Pseudomonas species may occur.
Write Your Own Review