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What is PRAS Media?

Prereduced Anaerobically Sterilized (PRAS) media is anaerobic culture media prepared and sterilized under oxygen-free conditions to eliminate molecular oxygen and prevent the formation of oxidative products, toxic to anaerobic bacteria. This ensures an optimal environment for cultivating oxygen-sensitive anaerobes, making PRAS media critical for accurate diagnosis in clinical microbiology labs.
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Why Choose PRAS Media?

OxyPRAS Plus media maximize the recovery of anaerobic bacteria, essential for diagnosing infections like abscesses, wound infections, and gastrointestinal diseases. Key benefits include:

Superior Recovery Rates

A 1970 study by McMinn and Crawford demonstrated that PRAS media recovered over twice the number of anaerobic bacteria from clinical specimens compared to conventional methods. (Ref. https://pubmed.ncbi.nlm.nih.gov/4908525/)

Oxygen-Free Preparation

Manufactured under Oxygen depleted conditions by use of the Oxyrase Enzyme System, preventing oxidation and maintaining a reduced state for anaerobe growth.

Convenience and Efficiency

Pre-reduced, ready-to-use media save lab time and eliminate additional reduction steps.

Extended Shelf Life

Packaged using oxygen impermeable film, offering a 90 day shelf life, minimizing waste.

Expert Endorsement

The Clinical Microbiology Procedures Handbook (2016) recommends PRAS media as the optimal choice for anaerobic bacteria growth (Wiley Online Library).

Cost Effective

High recovery rates and minimal preparation make PRAS media a cost-effective solution for clinical diagnostics.

Research-backed Superiority

Our comparative study (2023) evaluated OxyPRAS Plus plates, non-PRAS plates, and post-reduced plates inoculated with Bacteroides fragilis, Fusobacterium nucleatum, and Porphyromonas levii. Results showed PRAS plates consistently outperformed others, especially when working with Oxygen sensitive anaerobes.

Porphyromonas levii

Pinpoint colonies without PRAS can be missed. Many more colonies on PRAS.*

*All plates incubated for 72 hours at 37°C.

Fusobacterium nucleatum

The colony size is about the same.  Colony count significantly greater on PRAS versus Non-PRAS.*

Bacteroides fragilis

Although there is no difference in colony count, the colonies are bigger on PRAS.

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    What Makes OxyPRAS Different?

    OxyPRAS Plus plates are fortified with the Oxyrase Enzyme System, which actively reduces the media environment unlike traditional reducing agents. This allows technicians to handle unpackaged plates on the benchtop for up to 2 hours without risking oxidation of the plate which can be inhibitory to oxygen-sensitive anaerobes.

    To test this, we compared aerobically manufactured, non-PRAS plates, Post-reduced non-PRAS plates, Traditional PRAS plates, and OxyPRAS Plus Plates in their ability to recover Porphyromonas levii. Plates were left out on the benchtop for 0, 30, 60, 120, and 180 minutes to test how oxidation of the plate affects the recovery of P. levii.

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