Objective: Clostridium difficile variant strains in the genetic region Pathogenicity Locus (PaLoc) have been involved in C. difficile - associated disease (CDI) and outbreaks in hospital settings. The increased incidence and severity of CDI in the last decade, particularly in North America and Europe, have brought renewed focus on the most appropriate method to detect C. difficile and/or its toxins in stool. The aim of this prospective study was to evaluate the diagnostic performance of the gene amplification system IllumigeneTM C. difficile (Meridian Bioscience, USA), targeting a fragment of the toxin C. difficile A gene (tcdA), in routinely investigation as compared to toxigenic culture and Immuno-Chromatographic assay (IC) for toxin A/ B and glutamate dehydrogenase (GDH). Methods: Analytic sensitivity was determined by using experimentally seeded samples with known amounts of reference C. difficile strains VPI10463 (ToxA+ ToxB+), ATCC 70057 (ToxA- ToxB-). Analytic specificity was tested by using the DNA extracted from faecal samples containing Salmonella spp., Helicobacter pylori, Staphylococcus aureus, Giardia intestinalis, Entamoeba coli, Entamoeba dispar, Blastocystis hominis, as the template. A total of 201 faecal samples from 189 hospitalized patients with suspected CDI, collected over a 3 months period, were investigated by Illumigene, toxigenic culture and IC (C.DIFF QUIK CHEK Complete: TechLab, USA) for the presence of toxin A/B and GDH. Faecal samples with discordant results were analyzed by a duplex PCR for the detection of tcdA/tcdB genes. Results: For reference strains a detection limit of 5 and 1000 CFU/g for Illumigene and for IC, respectively, was observed. DNA from the enteropathogenic bacteria other than C. difficile and from parasites was not detected by Illumigene. Among 201 analyzed samples, 70 were positive and 131 negative, based on the combination of the results of the different assays. Of the 131 negative samples, 127 were negative with all methods (concordance 96.9%) and four were positive by the GDH assay alone. Forty-three samples were positive for all assays with a 61% concordance. Results of discordant samples showed a 100% agreement with Illumigene. Conclusion: The Illumigene system showed sensitivity and specificity comparable to those of the toxigenic culture and IC. It is currently advantageously applied in our laboratory: results are available within 1 hour and a specific antibiotic therapy can be promptly administered to the patients.

Evaluation of the DNA amplification assay IllumigeneTM system for the diagnosis of Clostridium difficile infection / Calderaro, Adriana; Buttrini, Mirko; Martinelli, Monica; Gorrini, Chiara; Montecchini, Sara; Covan, Silvia; Chezzi, Carlo. - In: CLINICAL MICROBIOLOGY AND INFECTION. - ISSN 1198-743X. - 18, S3:(2012), pp. 667-667. (Intervento presentato al convegno 22nd European Congress of Clinical Microbiology and Infectious Diseases tenutosi a London nel 31 Marzo - 4 Aprile 2012) [10.1111/j.1469-0691.2012.03802.x].

Evaluation of the DNA amplification assay IllumigeneTM system for the diagnosis of Clostridium difficile infection

CALDERARO, Adriana;BUTTRINI, Mirko;MARTINELLI, Monica;GORRINI, Chiara;MONTECCHINI, Sara;COVAN, Silvia;CHEZZI, Carlo
2012-01-01

Abstract

Objective: Clostridium difficile variant strains in the genetic region Pathogenicity Locus (PaLoc) have been involved in C. difficile - associated disease (CDI) and outbreaks in hospital settings. The increased incidence and severity of CDI in the last decade, particularly in North America and Europe, have brought renewed focus on the most appropriate method to detect C. difficile and/or its toxins in stool. The aim of this prospective study was to evaluate the diagnostic performance of the gene amplification system IllumigeneTM C. difficile (Meridian Bioscience, USA), targeting a fragment of the toxin C. difficile A gene (tcdA), in routinely investigation as compared to toxigenic culture and Immuno-Chromatographic assay (IC) for toxin A/ B and glutamate dehydrogenase (GDH). Methods: Analytic sensitivity was determined by using experimentally seeded samples with known amounts of reference C. difficile strains VPI10463 (ToxA+ ToxB+), ATCC 70057 (ToxA- ToxB-). Analytic specificity was tested by using the DNA extracted from faecal samples containing Salmonella spp., Helicobacter pylori, Staphylococcus aureus, Giardia intestinalis, Entamoeba coli, Entamoeba dispar, Blastocystis hominis, as the template. A total of 201 faecal samples from 189 hospitalized patients with suspected CDI, collected over a 3 months period, were investigated by Illumigene, toxigenic culture and IC (C.DIFF QUIK CHEK Complete: TechLab, USA) for the presence of toxin A/B and GDH. Faecal samples with discordant results were analyzed by a duplex PCR for the detection of tcdA/tcdB genes. Results: For reference strains a detection limit of 5 and 1000 CFU/g for Illumigene and for IC, respectively, was observed. DNA from the enteropathogenic bacteria other than C. difficile and from parasites was not detected by Illumigene. Among 201 analyzed samples, 70 were positive and 131 negative, based on the combination of the results of the different assays. Of the 131 negative samples, 127 were negative with all methods (concordance 96.9%) and four were positive by the GDH assay alone. Forty-three samples were positive for all assays with a 61% concordance. Results of discordant samples showed a 100% agreement with Illumigene. Conclusion: The Illumigene system showed sensitivity and specificity comparable to those of the toxigenic culture and IC. It is currently advantageously applied in our laboratory: results are available within 1 hour and a specific antibiotic therapy can be promptly administered to the patients.
2012
Evaluation of the DNA amplification assay IllumigeneTM system for the diagnosis of Clostridium difficile infection / Calderaro, Adriana; Buttrini, Mirko; Martinelli, Monica; Gorrini, Chiara; Montecchini, Sara; Covan, Silvia; Chezzi, Carlo. - In: CLINICAL MICROBIOLOGY AND INFECTION. - ISSN 1198-743X. - 18, S3:(2012), pp. 667-667. (Intervento presentato al convegno 22nd European Congress of Clinical Microbiology and Infectious Diseases tenutosi a London nel 31 Marzo - 4 Aprile 2012) [10.1111/j.1469-0691.2012.03802.x].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2433188
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