Ward C.,Center for Clinical Infection and Diagnostics Research |
Stocker K.,Viapath LLP |
Begum J.,Viapath LLP |
Wade P.,Center for Clinical Infection and Diagnostics Research |
And 3 more authors.
European Journal of Clinical Microbiology and Infectious Diseases | Year: 2015
Molecular assays designed to provide bacterial identification and detection of resistance genes directly from positive blood cultures can significantly reduce the time to definitive results. This has the potential to improve patient management and antimicrobial stewardship. However, the extent of such an impact is yet to be fully assessed. We tested two such assays, the Verigene® System Bloodstream Infection Tests (Nanosphere, Inc., Northbrook, IL, USA) (both Gram-positive and Gram-negative cartridges) and the FilmArray® Blood Culture Identification Panel (BioFire® Diagnostics, Inc., Salt Lake City, UT, USA). We compared their accuracy and speed of organism and resistance gene identification to conventional culture-based methods for 173 positive blood cultures. We also retrospectively determined, for organisms deemed not to be contaminants, the potential impact on antimicrobial prescribing. Both the Verigene® and FilmArray® assays accurately identified organisms, on average, 27.95 and 29.17 h earlier than conventional methods, respectively. There were a significant number of false-positives for Pseudomonas aeruginosa with the FilmArray® assay, which may have been related to contamination of the bioMérieux BacT standard anaerobic blood culture bottles, which the manufacturer has acknowledged. Both panels provided results significantly faster than conventional methods. In our setting, the extent of the potential positive impact on antimicrobial prescribing was modest (9 out of 173 samples). However, this may be an underestimation, since probable contaminants were not included in this analysis. In conclusion, both panels gave accurate results with significantly improved turnaround times. © 2014, Springer-Verlag Berlin Heidelberg.
Batra R.,St Thomas Hospital |
Judd E.,ViaPath LLP |
Eling J.,Guys & St Thomas Nhs Foundation Trust |
Newsholme W.,St Thomas Hospital |
Goldenberg S.D.,St Thomas Hospital
European Journal of Clinical Microbiology and Infectious Diseases | Year: 2016
The purpose of this study was to evaluate the level of agreement of the BD Max™ Enteric Parasite Panel (EPP) with microscopy for the detection of Giardia duodenalis, Cryptosporidium spp. and Entamoeba histolytica in stool samples. A total of 372 stool samples (partly collected on the basis of positive microscopy and partly unselected, consecutive sample submitted for parasite investigation) were tested with EPP according to manufacturer’s instructions and also using microscopy according to standard techniques. Discrepant samples were further tested using PCR by the National Parasitology reference laboratory. Levels of agreement and laboratory turnaround times were measured and compared. Overall, positive and negative percent agreement was high between the two methods. However, microscopy resulted in four false positives and one false negative for G. duodenalis and two false positives for Cryptosporidium. Additionally, microscopy could not differentiate between E. histolytica and Entamoeba dispar. Median laboratory turnaround time was 65 hours for microscopy; results from EPP could be available after four hours. Blastocycstis hominis was detected by microscopy in one sample and would have been missed if only EPP was performed. The EPP was a good alternative to microscopy, detecting a small number of additional positives that were missed by microscopy. The assay is significantly faster than microscopy and allows laboratory workflows to be streamlined. The risk of missing parasites that are not included in the EPP appears to be minimal in the studied population; however, there may be certain patient groups who would benefit from microscopic examination of stools. © 2016 Springer-Verlag Berlin Heidelberg