Columbia CNA Agar (Sheep blood 5%)
Selective medium for the isolation of streptococci, staphylococci and pneumococci
TYPICAL FORMULA (g/l) Peptospecial 23.0 Starch 1.0 Sodium Chloride 5.0 Colistin Sulphate 0.01 Nalidixic Acid 0.015 Sheep Blood Defibrinated 50.0 ml Agar 14.0 Final pH 7.3 ± 0.2
DESCRIPTION Columbia CNA Agar (Sheep blood 5%) is used as a selective growth medium for the isolation and differentiation of Gram-positive cocci from clinical and nonclinical specimens containing mixed flora. PRINCIPLE Peptospecial is a source of nitrogen, sulfur, carbon and other essential growth factors. Sodium chloride maintains osmotic balance of the medium. Colistin and nalidixic acid constitute selective agents: particularly colistin destroys cell membrane of Gram-negative bacteria, whilst nalidixic acid inhibits DNA replication in Gram-negative bacteria. Defibrinated sheep blood supplies further growth factors for fastidious microorganisms and allows to enhance haemolytic reactions. Agar is the solidifying agent.
TECHNIQUE Inoculate the plates by streaking the specimen onto the surface of the medium using a sterile loop, in order to isolate single colonies. Incubate at 36 ± 1°C for 18-48 hours, under aerobic, anaerobic or microaerophilic conditions.
INTERPRETATION OF RESULTS Examine plates for growth and hemolytic reactions. Four types of hemolysis on blood agar media can be described: 1. α-hemolysis is the reduction of hemoglobin to methemoglobin in the medium surrounding the colony, causing a greenish discolouration of the medium. 2. β-hemolysis is the lysis of red blood cells, producing a clear zone surrounding the colony. 3. γ-hemolysis indicates no destruction of red blood cells and no change in the color of the medium. 4. ά-hemolysis indicates a partial lysis.
STORAGE AND TRANSPORT CONDITIONS 2-8°C away from light, until the expiry date on the label. However, our stability studies have shown that the transport at 18-25°C for 4 days, or at 35-39°C for 48 hours, does not alter in any way the performance of the product. Eliminate if signs of deterioration or contamination are evident.
WARNING AND PRECAUTIONS The product does not contain hazardous substances in concentrations exceeding the limits set by current legislation and therefore is not classified as dangerous. It is nevertheless recommended to consult the safety data sheet for its correct use. The product is designed for In vitro diagnostic use and must be used only by properly trained operators.
DISPOSAL OF WASTE Disposal of waste must be carried out according to the national and local regulations in force.
20 plate price 1600/-
100 plate price 6,600/-