Validation and Implementation of the GeneXpert MRSA/SA Blood Culture Assay in a Pediatric Setting

Spencer, David H.; Sellenriek, Patricia; Burnham, Carey‐Ann D.

doi:10.1309/ajcp07ugyokbvvnc

Cited by 65 publications

(40 citation statements)

References 8 publications

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“…Real-time PCR, which is the most rapid PCR method, needs delicate thermal control during the cycles and is sequence dependent, taking up to an hour [24] until the signal is detected against the background. In comparison, our PC nanostructured array operates at room temperature, irrespective of the size of the DNA sequences, and has assay times (1 h) that are comparable to real-time PCR, with a signal that was highly sensitive to the small number of complementary base pairs.…”

Section: Resultsmentioning

confidence: 99%

On-chip detection of a single nucleotide polymorphism without polymerase amplification

et al. 2014

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A nanoparticle-assembled photonic crystal (PC) array was used to detect single nucleotide polymorphism (SNP). The assay platform with PC nanostructure enhanced the fluorescent signal from nanoparticle-hybridized DNA complexes due to phase matching of excitation and emission. Nanoparticles coupled with probe DNA were trapped into nanowells in an array by using an electrophoretic particle entrapment system. The PC/DNA assay platform was able to identify a 1 base pair (bp) difference in synthesized nucleotide sequences that mimicked the mutation seen in a feline model of human autosomal dominant polycystic kidney disease (PKD) with a sensitivity of 0.9 fg/mL (50 aM)-sensitivity, which corresponds to 30 oligos/array. The reliability of the PC/DNA assay platform to detect SNP in a real sample was demonstrated by using genomic DNA (gDNA) extracted from the urine and blood of two PKD− wild type and three PKD positive cats. The standard curves for PKD positive (PKD+) and negative (PKD−) DNA were created using two feline-urine samples. An additional three urine samples were analyzed in a similar fashion and showed satisfactory agreement with the standard curve, confirming the presence of the mutation in affected urine. The limit of detection (LOD) was 0.005 ng/mL which corresponds to 6 fg per array for gDNA in urine and blood. The PC system demonstrated the ability to detect a number of genome equivalents for the PKD SNP that was very similar to the results reported with real time polymerase chain reaction (PCR). The favorable comparison with quantitative PCR suggests that the PC technology may find application well beyond the detection of the PKD SNP, into areas where a simple, cheap and portable nucleic acid analysis is desirable.

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Section: Resultsmentioning

confidence: 99%

On-chip detection of a single nucleotide polymorphism without polymerase amplification

et al. 2014

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“…When compared to conventional culture methods, both assays are reported to have high sensitivity and specificity for the identification of methicillin-susceptible S. aureus (MSSA) and MRSA, with a manufacturer's report suggesting 98.8-100% sensitivity and 97.2-100% specificity for the BD GeneOhm StaphSR assay, 12 and similar high reported rates of sensitivity and specificity for the Cepheid Xpert MRSA/SA assay. 24,27,28 In order to differentiate between S. aureus and other staphylococcal species, primers for a S. aureus species-specific marker are generally incorporated into molecular assays. The most common S. aureus species markers used to date are the staphylococcal nuclease (nuc) gene or the staphylococcal protein A (spa) gene.…”

Section: Rapid Molecular Detection Of S Aureus From Clinical Specimensmentioning

confidence: 99%

Contemporary genomic approaches in the diagnosis and typing of Staphylococcus aureus

2015

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“…Such kits, which generally use swab samples to detect colonisation, are now being evaluated for clinical fluids (i.e. blood, urine and respiratory secretions) for the characterisation of clinical infection [43, 44]. The obvious limitation is that they seek only single pathogens and resistances, and their main potential lies in screening or in outbreak investigation -answering the question e.g.…”

Section: Rapid Identification Of Pathogens and Their Resistancesmentioning

confidence: 99%

Revolutionising Bacteriology to Improve Treatment Outcomes and Antibiotic Stewardship

Livermore

Wain

2013

Infect Chemother

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Laboratory investigation of bacterial infections generally takes two days: one to grow the bacteria and another to identify them and to test their susceptibility. Meanwhile the patient is treated empirically, based on likely pathogens and local resistance rates. Many patients are over-treated to prevent under-treatment of a few, compromising antibiotic stewardship. Molecular diagnostics have potential to improve this situation by accelerating precise diagnoses and the early refinement of antibiotic therapy. They include: (i) the use of 'biomarkers' to swiftly distinguish patients with bacterial infection, and (ii) molecular bacteriology to identify pathogens and their resistance genes in clinical specimens, without culture. Biomarker interest centres on procalcitonin, which has given good results particularly for pneumonias, though broader biomarker arrays may prove superior in the future. PCRs already are widely used to diagnose a few infections (e.g. tuberculosis) whilst multiplexes are becoming available for bacteraemia, pneumonia and gastrointestinal infection. These detect likely pathogens, but are not comprehensive, particularly for resistance genes; there is also the challenge of linking pathogens and resistance genes when multiple organisms are present in a sample. Next-generation sequencing offers more comprehensive profiling, but obstacles include sensitivity when the bacterial load is low, as in bacteraemia, and the imperfect correlation of genotype and phenotype. In short, rapid molecular bacteriology presents great potential to improve patient treatments and antibiotic stewardship but faces many technical challenges; moreover it runs counter to the current nostrum of defining resistance in pharmacodynamic terms, rather than by the presence of a mechanism, and the policy of centralising bacteriology services.

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Validation and Implementation of the GeneXpert MRSA/SA Blood Culture Assay in a Pediatric Setting

Cited by 65 publications

References 8 publications

On-chip detection of a single nucleotide polymorphism without polymerase amplification

On-chip detection of a single nucleotide polymorphism without polymerase amplification

Contemporary genomic approaches in the diagnosis and typing of Staphylococcus aureus

Revolutionising Bacteriology to Improve Treatment Outcomes and Antibiotic Stewardship

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