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CAMPYLOBACTER AGAR BASE (KARMALI)

Code: CM0935

A blood free selective medium for the isolation of Campylobacter jejuni and Campylobacter coli when incubated at 42°C.

CAMPYLOBACTER SELECTIVE SUPPLEMENT (KARMALI)

Code: SR0167

MODIFIED KARMALI SELECTIVE SUPPLEMENT

Code: SR0205

Directions
Add 21.5g of Campylobacter Agar Base (Karmali) to 500ml of distilled water and bring to the boil to dissolve. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C. Aseptically add 1 vial of Campylobacter Selective Supplement (Karmali) SR0167 or Modified Karmali Selective Supplement SR0205, reconstituted as directed.. Mix well and pour into sterile Petri dishes.

Description
Campylobacter Medium (Karmali) is based on the formulation described by Karmali et al.¹ and is recommended for the isolation of Campylobacter jejuni and Campylobacter coli from clinical specimens.

The original Campylobacter Blood Free medium in the Oxoid product range contains sodium pyruvate in the agar base. Campylobacter Medium (Karmali) incorporates this ingredient into the selective supplement. The original medium also contains sodium desoxycholate for the inhibition of Gram positive organisms, whereas with Campylobacter Medium (Karmali) suppression of Gram positives is achieved by the inclusion of vancomycin. Modified Karmali Selective Supplement SR0205 offers a cycloheximide free alternative by utilising amphotericin B as an antifungal agent³.

Campylobacter jejuni strains produce grey, moist, flat spreading colonies after 42 hour incubation at 42°C.

If plates are first examined after 24 hours incubation, read them immediately and quickly return them to a reduced oxygen atmosphere to ensure continued viability of the more oxygen-sensitive strains.

At 42°C selectivity is increased and growth is faster but non-thermophilic strains will not grow e.g. Campylobacter fetus subsp. fetus.
Colonies tend to swarm when initially isolated from clinical specimens.

Technique
1. Prepare Campylobacter Selective Medium (Karmali) plates as described in the directions for use.
2. Emulsify approximately 0.5g of the specimen in 5ml of sterile 0.1% peptone water to form a 1:10 dilution.
3. Inoculate on to selective medium with cotton tipped swabs so that single isolated colonies are formed.
4. Incubate the plates in an atmosphere consisting of approximately 5-6% oxygen, 10% carbon dioxide and 84-85% nitrogen for 48 hours at 42°C. This can best be achieved by using the Oxoid Gas Generating Kit for Campylobacters BR0056 in conjunction with the Oxoid Anaerobic Jar and an active catalyst BR0042. For jars of smaller capacity (2.5 litres) use the Oxoid Gas Generating Kit for Campylobacters BR0060. Alternatively use CampyGen CN0025 or CN0035. CampyGen does not require the addition of water or a catalyst.
5. Examine the plates and confirm the typical colonies as Campylobacter jejuni or Campylobacter coli. A simple schema for differentiating Campylobacter species is described by Skirrow and Benjamin².

Storage conditions and Shelf life
Campylobacter Agar Base (Karmali) should be stored tightly capped in the original container in a cool, dry place away from bright light. When stored at 10-30°C the medium will remain stable until the expiry date printed on the label.

Appearance
Dehydrated medium: Black, free-flowing powder
Prepared medium: Black gel

Quality control

* This organism is available as a Culti-Loop®

Precautions
Campylobacter Selective Supplement (Karmali) SR0167 contains cycloheximide which is toxic.
Note the precautions to be taken under HAZARDOUS  Products section of the Manual.

References
1. Karmali M.A., Simor A.E., Roscoe M., Fleming P.C, Smith S.S. and Lane J. (1986) J.Clin.Micro. 23. 456-459.
2. Skirrow M.B. and Benjamin J. (1980) J.Clin.Path. 33.1122.
3. Data on file at Oxoid.