New Thermo Scientific Medium Enhances MRSA Screening

Thermo Scientific Limited has launched a new broth medium for the quick and easy screening of clinical samples for the presence of MRSA. Available in a convenient, ready-to-use format, Thermo Scientific Selective Mannitol Broth (as originally described by Gurran et al. Ref 1) saves time and resources by enabling the laboratory to screening out negative samples.

Samples from patients and hospital staff are simply inoculated into vials containing 5 ml Selective Mannitol Broth (order code: EB1016C) and incubated overnight. Selective agents within the medium are designed to inhibit the growth of other organisms, whilst permitting the MRSA to grow. MRSA are able to ferment the mannitol in the broth. This acidifies the medium, causing the colour to change from red to yellow, giving a presumptive positive reaction. All the negative broths can be discarded, while confirmatory tests are performed on isolates from the positive broths only.

Multiple samples from an individual can be pooled (depending on knowledge of their previous MRSA status), reducing the number of tests required, and the ability to screen out negative cultures reduces the number of confirmation tests required.

A recent review of MRSA isolation policies concluded that it should be possible to eradicate an endemic MRSA problem with an effective isolation policy (Ref 2), over time. In addition, such a policy could result in cost savings by reducing length of stay in the hospital. New Thermo Scientific Selective Mannitol Broth contributes to an effective isolation policy by providing a fast and efficient method for the screening of clinical samples for MRSA.

References:
1. Gurran, C., Holliday, M.G., Perry, J.D., Ford, M., Morgan, J. and Orr,
K.E. (2002) J Hosp Infect 52: 148-151, A Novel Selective Medium for the Detection of Methicillin-Resistant Staphylococcus aureus Enabling Results Reporting in Under 24hrs.
2. Cooper, B.S. et al. (2003) Health Technology Assessment 7 No. 39; Ó Queen's Printer and Controller of HMSO 2003, Systematic Review of Isolation Policy of Methicillin-Resistant Staphylococcus aureus; a Review of the Literature with Epidemiological and Economical Modelling.