Overview:
Skirrow's Campylobacter Agar (also known as Skirrow's Medium or Campylobacter Selective Agar - Skirrow) is a selective, enriched blood agar medium developed by Skirrow in 1977 for the primary isolation of Campylobacter species, particularly thermophilic strains like C. jejuni and C. coli, from clinical fecal specimens, food, and environmental samples. It uses a nutritionally rich base (equivalent to Blood Agar Base No. 2) supplemented with 5-7% lysed horse blood or 10% defibrinated sheep blood to provide essential growth factors such as hemin (X-factor) and NAD (V-factor), while the Skirrow antibiotic supplement (vancomycin, polymyxin B, and trimethoprim) inhibits competing enteric flora like E. coli, Proteus, and Enterococcus. Incubation under microaerophilic conditions (5% O?, 10% CO?) at 42�C for 24-48 hours yields characteristic flat, grayish-white, mucoid, spreading colonies (1-3 mm) that are typically non-hemolytic.
Applications:
?? Selective isolation of Campylobacter jejuni and C. coli from human/animal feces for diagnosing campylobacteriosis
?? Detection in food microbiology, including poultry, dairy, and water samples per ISO 10272 and FDA-BAM guidelines
?? Environmental monitoring of Campylobacter in sewage, soil, and contaminated sites
?? Subculture from enrichment broths (e.g., Campy Enrichment Broth) or transport media for delayed analysis
Key Features:
?? Skirrow antibiotics provide targeted inhibition of Gram-positive/negative bacteria without affecting Campylobacter recovery (>80% for ATCC 29428)
?? Blood enrichment supports luxuriant growth of fastidious microaerophiles, neutralizing oxygen toxicity
?? Promotes distinctive colony morphology (gray, flat, irregular edges) under elevated temperature (42�C) for presumptive identification
?? Validated in CLSI, APHA, and EU standards; superior to non-selective blood agar for mixed specimens
?? Optional amphotericin B variant inhibits fungal overgrowth in heavily contaminated samples
Composition (per liter):
Proteose Peptone � 15.0 g
HL Digest (Lactic Acid Hydrolysate of Casein or Liver Digest) � 2.5 g
Yeast Extract � 5.0 g
Sodium Chloride (NaCl) � 5.0 g
Agar � 12.0 g
Lysed Horse Blood (5-7%) or Defibrinated Sheep Blood (10%) � 50-70 mL
Skirrow Selective Supplement: Vancomycin � 10 mg; Polymyxin B � 2,500 IU; Trimethoprim � 5 mg
Final pH: 7.4 � 0.2 at 25�C
Preparation:
Suspend 39.5 g of the dehydrated base in 1 liter of purified/distilled water. Heat with gentle agitation to boiling until completely dissolved (do not overheat). Autoclave at 121�C (15 psi) for 15 minutes. Cool to 45-50�C in a water bath. Aseptically add 50-70 mL sterile lysed horse blood (or 100 mL defibrinated sheep blood) and the rehydrated Skirrow supplement (one vial per liter). Mix thoroughly and pour into sterile Petri plates (20-25 mL per plate). Allow to solidify at room temperature and dry the surface briefly. Prepared plates should appear reddish-brown, opaque, and free of bubbles or precipitates.
Storage:
Dehydrated medium: Store in a tightly closed container at 10�30�C, protected from moisture, light, and humidity; stable until expiry date (typically 3 years).
Prepared plates: Store at 2�8�C in sealed plastic bags; use within 1-2 weeks. Discard if dehydrated, hemolyzed, discolored, or contaminated.
?? For laboratory and research use only. Not for diagnostic procedures without proper validation. Not for human or veterinary consumption. Handle under biosafety level 2; use Universal Precautions due to animal blood�wear gloves and eye protection. Autoclave waste before disposal. Incubate in microaerophilic systems; some strains may grow poorly at 37�C or require 42�C for optimal recovery. Not suitable for non-thermophilic species without modifications.3.1s