Multicentre evaluation of laboratory work time and cost for real-time PCR tests for methicillin-resistant Staphylococcus aureus compared to microbiological culture

Abstract number: O26

Peterson L., Woods C.W., Allen S., Pombo D., Onderdonk A., Liesenfeld O.

Objectives: MRSA continues to increase globally. Rapid detection of MRSA colonization followed by appropriate isolation can reduce transmission and infection in healthcare settings (Ann Int Med 148:409–418, 2008). A concern raised is the cost of molecular assays plus the personnel time to perform this testing compared to culture. The BD GeneOhmTM MRSA (BD) test is a FDA cleared diagnostic assay for rapid detection of MRSA. Our objective was to compare personnel work time and cost needed for this assay and the LightCycler® MRSA Advanced test (Roche) to culture.

Methods: Double headed swabs were used to collect anterior nasal specimens from each subject. For the BD test, one swab was broken off in sample buffer tube, DNA was extracted and rt-PCR performed according to package insert. For the Roche test, DNA was extracted and rt-PCR performed according to proposed package insert. For culture, one swab was plated directly to CHROMagarTM as well as to an enrichment broth that was subsequently plated to CHROMagarTM. Colonies resembling Staphylococcus species were confirmed as MRSA by standard methods. Processing time and cost of supplies were compared for these tests.

Results: Total hands-on technologist processing time for an average of 25 specimens was 75.4 min for the BD test (N = 263 runs) and 41 min for the Roche assay (N = 435 runs). The amplification and detection time was 61.8 and 77.6 min, respectively. Hands on time for enriched culture processing of 25 specimens is estimated at 63 min (AJCP 131:532–9, 2009). Potential reporting time for a final result was <2 hours for the rt-PCR tests and 48.7 hours for enriched culture. The reagent cost for culture, including or excluding broth enrichment, is somewhat lower (8–10 Euro) than the rt-PCR tests from BD and Roche; costs of rt-PCR tests are comparable between these two suppliers. New rt-PCR methods have a comparable time of processing and cost of materials, but offer potentially much faster reporting time than does culture. The hands on time for the Roche assay was 1.8 min/test on average compared to 3 min with the BD assay and 2.5 min/test for culture.

Conclusion: The Roche and BD tests had little difference in overall time to result. With respect to resource utilization, hands-on time for the Roche assay was lower than BD and culture; the cost per test is comparable for both PCR assays. Molecular assays are able to report results more rapidly compared to culture with comparable resource utilization.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
Back to top