Clinical utility of the Xpert MRSA assay for early detection of methicillin-resistant Staphylococcus aureus

Ae-Chin Oh, Jin Kyung Lee, Ha Na Lee, Young Jun Hong, Yoon Hwan Chang, Seok-Il Hong, Dong Ho Kim, Ae-Chin Oh, Jin Kyung Lee, Ha Na Lee, Young Jun Hong, Yoon Hwan Chang, Seok-Il Hong, Dong Ho Kim

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for many nosocomial and community-acquired infections, resulting in significant morbidity and mortality. A practical way to limit the spread of MRSA is early detection and proper treatment. However, screening culture for MRSA typically requires 2-3 days. The Xpert MRSA assay (Cepheid, Sunnyvale, CA, USA) is a real-time polymerase chain reaction-based assay developed for screening an MRSA-specific DNA sequence within the staphylococcal cassette chromosome in 2 h. Lower respiratory tract specimens, such as transtracheal aspirates (TTAs) and bronchoalveolar lavage fluid (BALF), are commonly obtained from intubated patients. Therefore, using the lower respiratory tract specimens with the Xpert MRSA assay may be a practical tool for patient care. We performed the Xpert MRSA assay on 108 TTA and 21 BALF specimens from 92 patients and compared the results to those obtained by culture. The two assays showed concordant results in 120 (93.0%) cases and discordant results in 9 (7.0%) cases, which were culture‑negative and Xpert MRSA-positive. Among the discordant cases, 5 patients developed culture-positive samples 2-15 days after the Xpert MRSA detected MRSA. We conclude that the Xpert MRSA assay is a rapid, sensitive and clinically useful test, particularly for the early detection of MRSA.

References

    1. Kim TS, Yi JY, Hong KH, Park JS, Kim EC. Distribution of virulence genes in spa types of methicillin-resistant Staphylococcus aureus isolated from patients in intensive care units. Korean J Lab Med. 2011;31:30–36.
    1. Van Hal SJ, Stark D, Lockwood B, Marriott D, Harkness J. Methicillin-resistant Staphylococcus aureus (MRSA) detection: comparison of 2 molecular methods (IDI-MRSA PCR assay and GenoType MRSA direct PCR assay) with 3 selective MRSA agars (MRSA ID, MRSASelect, and CHROMagar MRSA) for use with infection-control swabs. J Clin Microbiol. 2007;45:2486–2490.
    1. Hope WW, Morton AP, Looke DF, Schooneveldt JM, Nimmo GR. A PCR method for the identification of Staphylococcus aureus (MRSA) from screening swabs. Pathology. 2004;36:265–268.
    1. Stratidis J, Bia FJ, Edberg SC. Use of real-time polymerase chain reaction for identification of methicillin-resistant Staphylococcus aureus directly from positive blood culture bottles. Diagn Microbiol Infect Dis. 2007;58:199–202.
    1. Thomas LC, Gidding HF, Ginn AN, Olma T, Iredell J. Development of a real-time Staphylococcus aureus and MRSA (SAM) PCR for routine blood culture. J Microbiol Methods. 2007;68:296–302.
    1. Ulrich MP, Christensen DR, Coyne SR, et al. Evaluation of the Cepheid GeneXpert system for detecting Bacillus anthracis. J Appl Microbiol. 2006;100:1011–1016.
    1. Park SH, Jang YH, Sung HS, Kim MN, Kim JS, Park YJ. Performance evaluation of BD GeneOhm MRSA PCR assay for detection of nasal colonization of methicillin-resistant Staphylococcus aureus at endemic intensive care unit. Korean J Lab Med. 2009;29:439–447. (In Korean)
    1. Oberdorfer K, Pohl S, Frey M, Heeg K, Wendt C. Evaluation of a single-locus real-time polymerase chain reaction as a screening test for specific detection of Staphylococcus aureus in ICU patients. Eur J Clin Microbiol Infect Dis. 2006;25:657–663.
    1. Malhotra-Kumar S, Van Heirstraeten L, Lee A, et al. Evaluation of molecular assays for rapid detection of methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 2010;48:4598–4601.
    1. Laurent C, Bogaerts P, Scoevaerdts D, et al. Evaluation of the Xpert MRSA assay for rapid detection of methicillin-resistant Staphylococcus aureus from nares swabs of geriatric hospitalized patients and failure to detect a specific SCCmec type IV variants. Eur J Clin Microbiol Infect Dis. 2010;29:995–1002.
    1. Paule SM, Hacek DM, Kufner B, et al. Performance of the BN GeneOhm methicillin-resistant Staphylococcus aureus test before and during high-volume clinical use. J Clin Microbiol. 2007;45:2993–2998.
    1. Japanese Respiratory Society. Diagnosis of hospital-acquired pneumonia and methods of testing for pathogen. Respirology. 2009;14:S10–S22.
    1. Kluytmans J. Control of Staphylococcus aureus (MRSA) and the value of rapid tests. J Hosp Infect. 2007;65:100–104.
    1. Wolk DM, Picton E, Johnson D, et al. Multicenter evaluation of the Cepheid Xpert methicillin-resistant Staphylococcus aureus (MRSA) test as a rapid screening method for detection of MRSA in Nares. J Clin Microbiol. 2009;47:758–764.
    1. Roisin S, Laurent C, Nonhoff C, et al. Positive predictive value of the Xpert MRSA assay diagnostic for universal patient screening at hospital admission: influence of the local ecology. Eur J Clin Microbiol Infect Dis. 2011;31:873–880.
    1. Rossney AS, Herra CM, Brennan GI, Morgan PM, O’Connell BO. Evaluation of the Xpert methicillin-resistant Staphylococcus aureus (MRSA) assay using the GeneXpert real-time PCR platform for rapid detection of MRSA from screening specimens. J Clin Microbiol. 2008;46:3285–3290.
    1. San ND, Denis O, Gasasira MF, De Mendona, Nonhoff C, Struelens MJ. Controlled evaluation of the IDI-MRSA assay for detection of colonization by methicillin-resistant Staphylococcus aureus in diverse mucocutaneous specimens. J Clin Microbiol. 2007;45:1098–1101.
    1. Kelly PG, Grabsch EA, Howden BP, Gao W, Grayson ML. Comparison of the Xpert methicillin-resistant Staphylococcus aureus (MRSA) PCR assay, BD GeneOhm MRSA assay, and culture for detection of nasal and cutaneous groin colonization by MRSA. J Clin Microbiol. 2009;47:3769–3772.
    1. Sarikonda KV, Micek ST, Doherty JA, Reichley RM, Warren D, Koller MH. Methicillin-resistant Staphylococcus aureus nasal colonization is a poor predictor of intensive care unit-acquired of methicillin-resistant Staphylococcus aureus infections requiring antibiotic treatment. Crit Care Med. 2010;38:1991–1995.
    1. Holfelder M, Eigner U, Turnwald AM, Witte W, Weizenegger M, Fahr A. Direct detection of Staphylococcus aureus in clinical specimens by a nucleic acid-based hybridization assay. Clin Microbiol Infect. 2006;12:1163–1167.
    1. Paule SM, Pasquariello AC, Hacek DM, et al. Direct detection of Staphylococcus aureus from adult and neonate nasal swab specimens using real-time polymerase chain reaction. J Mol Diagn. 2004;6:191–196.

Source: PubMed

Sponsorer och medarbetare

Medicinska tillstånd

Läkemedelsinterventioner

3
Prenumerera