HiCrome™ C.auris (MDR) Selective Agar Base

Intended use

Recommended for selective isolation of Candida auris MDR strains from clinical samples and mixture of other Candida species.

Composition**

Final pH ( at 25°C) 6.0±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 47.35 gram in 1000 ml purified / distilled water. Heat to boiling to dissolve the medium completely. DO NOT AUTOCLAVE. Cool to 45-50°C. Aseptically add rehydrated contents of two vials of AntiF MDR Selective Supplement (FD360). Cool to 45-50°C. Mix well and pour into sterile Petri plates.

Principle And Interpretation

Candida auris has emerged as a resistant fungus which causes a serious global health threat. It is often resistant to multiple antifungal drugs commonly used to treat Candida infections. Some strains are resistant to all three available classes of antifungals (polyene, azoles and echinocardins). However it varies in the level of susceptibility. It was first isolated from the ear canal of a patient in Japan. Candida auris can grow at 42°C, but failed to grow in the presence of 0.01% or 0.1% cycloheximide (1).

HiCrome® C.auris MDR Selective Agar Base is recommended for the detection of multidrug resistant strains. Peptone provides nitrogenous and carbonaceous compounds, long chain amino acids, vitamins and other essential nutrients. Chromogenic mixture in the medium helps in imparting purple colour to Candida auris. Inhibitory mixture imparts selectivity to the medium wherein bacterial cultures are inhibited. The selective supplement and incubation temperature helps in selection of MDR C.auris strains.

C.auris can survive for weeks on plastic surfaces, has reduced susceptibility to quaternary ammonia disinfectants, and can colonize skin of healthy individuals. Therefore, strict BSL2 laboratory safety precautions must be followed, when working with this organism. Specifically, it is recommended that cultures are processed within BSL2 biosafety cabinet, gloves and lab coats are required.

Type of specimen

Clinical samples - skin samples (specifically axilla and groin), swabs taken from the nares, oropharynx, external ear canal and rectum, vaginal secretions.

Specimen Collection and Handling

1. Before beginning, perform hand hygiene and wear appropriate personal protective equipment (PPE) as indicated by the patient’s clinical care team (e.g., gloves, gown, mask).
2. Open the swab package and firmly rub the soft end of the collection swab cross the indicated site at least 3-5 times.
3. Transfer the swab and then process immediately or it can be kept at 2-8°C before transporting to the laboratory.
4. Strict BSL2 laboratory safety precautions must be followed.

After use, contaminated materials must be sterilized by autoclaving before discarding (2).

Warning and Precautions

In Vitro diagnostic Use only. For professional use only. Read the label before opening the container. Wear protective gloves/ protective clothing/eye protection/ face protection.

Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per established guidelines should be followed while handling clinical specimens. Safety guidelines may be referred in individual safety data sheets.

Limitations

1. Slight variation in colour for isolates may be observed as the reaction is based on the enzyme present in organism.
2. Growth of the organisms may vary depending on their susceptibility and resistance to antibiotic.
3. Further biochemical and serological tests must be performed for final confirmation.

Performance and Evaluation

Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.

Quality Control

Appearance Cream to beige homogeneous free flowing powder

Gelling Firm, comparable with 1.36% Agar gel

Colour and Clarity of prepared medium Light amber coloured, opaque gel forms in Petri plates

Reaction Reaction of 4.75% w/v aqueous solution at 25°C. pH : 6.0±0.2

pH 5.80-6.20

Cultural Response Cultural characteristics observed with added AntiF MDR Selective Supplement (FD360) after an incubation at 40-42°C for 40-48 hours.

Key : (*) Corresponding WDCM numbers.

Storage and Shelf Life

Store between 15-25°C in a tightly closed container and the prepared medium at 2-8°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated area protected from extremes of temperature and sources of ignition Seal the container tightly after use. Product performance is best if used within stated expiry period.

Disposal

User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow established laboratory procedures in disposing of infectious materials and material that comes into contact with clinical sample must be decontaminated and disposed of in accordance with current laboratory techniques (3,4).

Reference

1. Ramamurthy S.M., Chakraborty A., Candida auris candidaemia in Indian ICUs : analysis of risk factors. Journal of Antimicrobial Chemotherapy 2017, 72: 1794-1801
2. Procedure for Collection of Patient Swabs for Candida auris. Centres for Disease control and Prevention (CDC).
3. Isenberg, H.D. Clinical Microbiology Procedures Handbook 2nd Edition.
4. Jorgensen, J.H., Pfaller, M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W.(2015) Manual of Clinical Microbiology, 11th Edition. Vol. 1.