Comparison of Performance Characteristics of Aspergillus PCR in Testing a Range of Blood-Based Samples in Accordance with International Methodological Recommendations.

Standardized methodologies for the molecular detection of invasive aspergillosis (IA) have been established by the European Aspergillus PCR Initiative for the testing of whole blood, serum, and plasma. While some comparison of the performance of Aspergillus PCR when testing these different sample types has been performed, no single study has evaluated all three using the recommended protocols. Standardized Aspergillus PCR was performed on 423 whole-blood pellets (WBP), 583 plasma samples, and 419 serum samples obtained from hematology patients according to the recommendations. This analysis formed a bicenter retrospective anonymous case-control study, with diagnosis according to the revised European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) consensus definitions (11 probable cases and 36 controls). Values for clinical performance using individual and combined samples were calculated. For all samples, PCR positivity was significantly associated with cases of IA (for plasma, P = 0.0019; for serum, P = 0.0049; and for WBP, P = 0.0089). Plasma PCR generated the highest sensitivity (91%); the sensitivities for serum and WBP PCR were 80% and 55%, respectively. The highest specificity was achieved when testing WBP (96%), which was significantly superior to the specificities achieved when testing serum (69%, P = 0.0238) and plasma (53%, P = 0.0002). No cases were PCR negative in all specimen types, and no controls were PCR positive in all specimens. This study confirms that Aspergillus PCR testing of plasma provides robust performance while utilizing commercial automated DNA extraction processes. Combining PCR testing of different blood fractions allows IA to be both confidently diagnosed and excluded. A requirement for multiple PCR-positive plasma samples provides similar diagnostic utility and is technically less demanding. Time to diagnosis may be enhanced by testing multiple contemporaneously obtained sample types.

An overview of using fungal DNA for the diagnosis of invasive mycoses.

INTRODUCTION: Fungal PCR has undergone considerable standardization and, together with the availability of commercial assays, external quality assessment schemes, and extensive performance validation data, is ready for widespread use for the screening and diagnosis of invasive fungal disease (IFD). AREAS COVERED: Drawing on the experience and knowledge of the leads of the various working parties of the Fungal PCR initiative, this review will address general considerations concerning the use of molecular tests for the diagnosis of IFD, before focusing specifically on the technical and clinical aspects of molecular testing for the main causes of IFD and recent technological developments. EXPERT OPINION: For infections caused by Aspergillus, Candida, and Pneumocystis jirovecii, PCR testing is recommended, and combination with serological testing will likely enhance the diagnosis. For other IFD (e.g. mucormycosis), molecular diagnostics represent the only non-classical mycological approach toward diagnoses, and continued performance validation and standardization have improved confidence in such testing. The emergence of antifungal resistance can be diagnosed, in part, through molecular testing. Next-generation sequencing has the potential to significantly improve our understanding of fungal phylogeny, epidemiology, pathogenesis, mycobiome/microbiome, and interactions with the host, while identifying novel and existing mechanisms of antifungal resistance and novel diagnostic/therapeutic targets.

No dose-dependent tubulotoxicity of 5-aminosalicylic acid: a prospective study in patients with inflammatory bowel diseases.

BACKGROUND AND AIMS: Elevated levels of renal tubular markers in the urine are found in 20-30% of patients with chronic inflammatory bowel diseases. We investigated whether this reflects a dose-dependent tubulotoxicity of 5-aminosalicylic acid (5-ASA). PATIENTS AND METHODS: In an open, prospective, multicenter study 18 patients with Crohn's disease and 29 with ulcerative colitis were treated with 3 g 5-ASA or more daily as the sole drug for 6 weeks. Clinical activity (CDAI, CAI) and renal tubular markers [beta-N-acetyl-D-glucosaminidase (beta-NAG) and other proteins in urine] were monitored. We examined whether the proportion of patients with elevated beta-NAG is more than 15% higher (absolute difference) than that prior to treatment. RESULTS: The proportion decreased from 19.2% to 12.8% in the intention-to-treat analysis (n=47) and from 24.3% to 13.5% in the per-protocol analysis (n=37), which was not more than 15% higher than at baseline. Mean CDAI decreased from 222 to 146 and mean CAI from 7.3 to 3.1 (intention-to-treat analysis). Response to therapy was shown by 61% of patients with Crohn's disease and 66% of patients with ulcerative colitis. The cumulative dose of 5-ASA was not correlated with beta-NAG level in the urine. CONCLUSION: This study largely rules out that 5-ASA at 3 g or higher per day for 6 weeks induces renal tubular damage. Elevated renal tubular markers reflect inflammatory activity or an extraintestinal manifestation of inflammatory bowel diseases.