OxyPRAS Plus® Brucella Blood Agar Plate
OxyPRAS Plus® Brucella Blood Agar is a pre-reduced anaerobically sterilized (PRAS) Brucella blood agar plate for the primary isolation of anaerobic bacteria from clinical specimens. It is a non-selective, enriched medium with 5% sheep blood, hemin, and vitamin K1, manufactured and packaged in a reduced state so it arrives ready to inoculate with no post-reduction step.
At a glance
Catalog number: P-BRU-BA (single plate), P-BRU-10 (10-pack). Also in multi-packs M-BBK-2, M-BKP-3, M-BKBP-3.
Medium: Brucella agar base with 5% defibrinated sheep blood, hemin 5 mg/L, vitamin K1 1 mg/L. Initial pH 7.3.
Type: Non-selective, enriched. Supports strict and facultative anaerobes.
Shelf life: 4 months from manufacture. 28-day minimum guaranteed on arrival.
Storage: 2 to 8°C. Ships at room temperature.
Packaging: Individually sealed oxygen-impermeable pouch.
User QC: Listed as exempt under CLSI M22-A3. Lot QC performed by Oxyrase.
Regulatory: For in vitro diagnostic use. Manufactured in Mansfield, Ohio under ISO 9001:2015.
When to use it
Brucella blood agar is the workhorse non-selective plate in an anaerobic media set. Use it for primary isolation from any specimen submitted for anaerobic culture: abscess and wound aspirates, tissue, body fluids, and blood culture subcultures. Because it is non-selective, it recovers the full range of anaerobes present, including fastidious and slow-growing species, and it shows hemolysis and pigmentation that help with presumptive identification.
Most labs plate it alongside a selective plate or two. Pair it with OxyPRAS Plus® KVL for gram-negative anaerobes, OxyPRAS Plus® PEA to suppress swarming and gram-negative facultatives, and OxyPRAS Plus® BBE for the Bacteroides fragilis group. The OxyPRAS Plus® 3-pack bundles Brucella, PEA, and a BBE/KVL bi-plate for exactly this workflow.
Why PRAS manufacturing matters
Anaerobic media that is poured and packaged in air accumulates oxidation products before it ever reaches your bench. Those products inhibit the most oxygen-sensitive anaerobes, and the effect is invisible: the plate looks fine and simply reports no growth.
OxyPRAS Plus® plates are reduced with the Oxyrase® Enzyme System before sterilization and held in a reduced state through storage and use. In our PRAS vs. non-PRAS comparison, 8 of 30 non-PRAS Brucella plates inoculated with Porphyromonas levii grew nothing at all, while 0 of 30 OxyPRAS Plus® plates failed. OxyPRAS Plus® plates also tolerate up to 2 hours of ambient oxygen exposure during setup without inhibitory oxidation, which gives the bench flexibility to batch work and to use automated streaking platforms.
Read the full data in The Plate That Reports Nothing and the oxygen exposure white paper.
Formulation
Approximate composition per liter of deionized water. Initial pH 7.3 ± 0.2. Production lots may be adjusted to offset raw material variance in order to meet performance criteria.
| Component |
Amount |
| Enzymatic digest of casein |
10.0 g |
| Enzymatic digest of animal tissue |
10.0 g |
| Yeast extract |
2.0 g |
| Sodium chloride |
5.0 g |
| Dextrose |
1.0 g |
| Sodium bisulfite |
0.1 g |
| L-cysteine |
1.0 g |
| Agar |
15.0 g |
| Hemin |
5.0 mg |
| Vitamin K1 |
1.0 mg |
| Defibrinated sheep blood |
51.0 mL |
| Oxyrase® Enzyme System |
proprietary |
Vitamin K1 and hemin supply growth factors for the pigmenting Bacteroides and Prevotella group and improve recovery of some gram-positive non-spore-forming anaerobes. Sheep blood adds nutrients and allows hemolytic reactions to be read.
Quality control
Samples of every lot are tested to Oxyrase specifications incorporating CLSI M22-A3. The following results are confirmed before release:
| Organism |
ATCC |
Expected result |
| Bacteroides fragilis |
25285 |
Growth in 2 to 3 days |
| Clostridium perfringens |
13124 |
Growth in 2 to 3 days; hemolysis |
| Fusobacterium nucleatum |
25586 |
Growth in 2 to 3 days |
| Prevotella melaninogenica |
25845 |
Growth in 2 to 3 days |
| Peptostreptococcus anaerobius |
27337 |
Growth in 2 to 3 days |
Uninoculated medium is dark red with no surface imperfections. Brucella blood agar is listed as exempt from user quality control under CLSI M22-A3; each laboratory should still establish its own QC program in line with its accreditation requirements, and the organisms above are recommended if you choose to test.
Directions for use
- Allow plates to reach room temperature before use.
- Remove the plate from the pouch.
- Check for contamination, oxidation (a bright red rather than dark red surface), and the expiration date.
- Inoculate and streak using standard technique.
- Invert and incubate at 35 to 37°C in an anaerobic bag, jar, or chamber.
- Include an anaerobic indicator such as OxyBlue™ to confirm anaerobiosis.
- Read plates after 2 to 3 days.
Anaerobic incubation is still required. PRAS manufacturing protects the medium before and during setup; it does not replace the anaerobic atmosphere during incubation.
Storage, shelf life and guarantee
Plates ship at room temperature and should be stored at 2 to 8°C on receipt. Expiration is 4 months from date of manufacture; the actual date is printed on each plate. Oxyrase guarantees at least 28 days of shelf life from the ship date, and longer dating can be arranged when you order. If OxyPRAS Plus® Brucella Blood Agar plates arrive short-dated, contaminated, or oxidized, or fail when used as directed, we refund the purchase price. Contact us with the lot number printed on the plate.
Limitations
- Supports both strict and facultative anaerobes. Colony types require additional identification.
- Some beta-hemolytic species can show a greenish reaction that resembles alpha-hemolysis because of the medium’s carbohydrate content.
- The Oxyrase® Enzyme System contains a penicillin-binding protein that may interfere with penicillin and some related antibiotics. Do not use these plates for susceptibility testing.
- Contains material of animal origin. Source animals are documented free of BSE/TSE.
Frequently asked questions
Do I need to reduce the plates before inoculating?
No. OxyPRAS Plus® plates are reduced during manufacturing and stay reduced in the sealed pouch. Open, inoculate, and incubate.
How long can the plate sit on the bench after opening?
Up to 2 hours of ambient oxygen exposure without inhibitory oxidation, based on our oxygen exposure study. Inoculate as soon as practical, but you do not need to rush plates into the jar one at a time.
Does my lab have to run QC on each lot?
Brucella blood agar is on the CLSI M22-A3 list of media exempt from user QC because manufacturer QC is sufficient. Each lot is tested by Oxyrase before release. Your accreditation program may still ask you to document receipt and inspection.
Can I use it with an automated streaker?
Yes. The 2-hour oxygen tolerance means plates can be loaded and streaked on automated platforms without a separate reduction step.
Is it available through my distributor?
Yes, through Fisher Scientific and Cardinal Health, or direct from Oxyrase. Ask us about volume pricing for standing orders.
