Comparison of an enrichment broth-enhanced commercial PCR procedure versus bacteriological culture for separating non-colonized from suspected or colonized MRSA individuals

Abstract

The aim of the study presented here was to evaluate an enrichment broth-enhanced commercial PCR procedure for excluding the presence of meticillin-resistant Staphylococcus aureus (MRSA) in patient samples in less than 36 h. In The Netherlands to date, all MRSA epidemics have been successfully controlled with the Dutch search-and-destroy policy. However, PCR facilitates more rapid screening for MRSA than traditional culture. One commercial PCR option is the hyplex StaphyloResist(R) PCR assay (Biologische Analysensystem GmbH, Lich, Germany), which detects Staphylococcus aureus and the mecA gene in MRSA as well as in coagulase-negative staphylococci (CoNS). This assay was used to test a total of 939 specimens obtained from 346 individuals. Following resolution of all discrepancies, the prevalence, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for all separate specimens were 9.0, 97.6, 83.7, 37.4 and 99.7%, respectively, and for specimens grouped according to daily episode submitted per individual, they were 7.5, 97.4, 77.2, 26.2 and 99.7%, respectively. These results led to the introduction of this PCR into the hospital laboratory's routine for the purpose outlined above.

Current Trends in Rapid Diagnostics for Methicillin-Resistant Staphylococcus aureus and Glycopeptide-Resistant Enterococcus Species

“…NPVs were similar and high for both methods (99.5%); however, the PPV for the Hyplex StaphyloResist was only 31.4% (11). Wagenvoort et al showed that pooling specimens (nose, throat, perineum, wounds/infections) followed by an 18-h enrichment in a nonselective broth could increase the sensitivity (97.6%), and to some extent, the PPV (37.4%) of the Hyplex StaphyloResist, while still retaining a high specificity (83.7%) and NPV (99.7%) (41). A markedly low PPV and a high frequency of false-positive results are observed with the Hyplex StaphyloResist assay because this assay detects two unlinked markers (an S. aureus species-specific gene and mecA), and mixed cultures of MSSA and MRCoNs are likely to give positive results.…”

Epidemiology of MRSA and current strategies in Europe and Japan

“…Despite increasing knowledge, more rapid detection techniques, including PCR [6], and interventions with regard to the multi-resistant strains problem and optimal treatment of infection-diseased patients worldwide, the trends in recent years show that the future pertaining to MRSA is not viewed optimistically by various experts in the field.…”

“…The reference literature for the individual countries is listed as follows: A: [7], [8], [9], [10], [11], D: [12], [13], [14], [15], [16], [17], [18], [19], DK/FI/SE/NO/IS: [20], [21], [22], [23], [24], [25] [26], ES: [27], [28], [29], [30], [31], [32], [33], [34], [35], FR: [36], [37], [38], [39], [40], HU: [41], [42], [43], IT: [44], [45], [46], [47], [48], [49], JP: [50], [51], [52], [53], [54], [55], [56], [57], [58], NL: [6], [59], [60], [61], [62], [63], [64], [65]. …”

“…During the workshop, participants representing clinical microbiologists and leading experts of their respective countries presented and discussed issues pertaining to MRSA such as screening, laboratory diagnostic with particular emphasis on more rapid diagnostic approaches like application of chrome-agar plates and the PCR assay technique [6], isolation precautions, decolonisation, burden for the individual patient and society, and the emerge of community-associated MRSA.…”

Rapid testing for methicillin-resistant Staphylococcus aureus: Implications for antimicrobial stewardship

“…10,11 The sensitivity and specificity of the hyplex StaphyloResist assay in the detection of MRSA have been tested in studies involving the use of nasal swabs and other body-surface swabs, but the assay has not been evaluated as a tool to guide antimicrobial therapy. 12,13 Generally, the assay was found to have reasonably good sensitivity, but its specificity (83.7-90%) was deemed to be on the low end of the range of acceptability; such marginal specificity could result in a substantial rate of false-positive results if the assay were to be put into widespread use.…”