Magicplex(TM) Sepsis Real-Time test to improve bloodstream infection diagnostics in children

Burden of bacterial bloodstream infections and recent advances for diagnosis

Bloodstream infections (BSIs) and subsequent organ dysfunction (sepsis and septic shock) are conditions that rank among the top reasons for human mortality and have a great impact on healthcare systems. Their treatment mainly relies on the administration of broad-spectrum antimicrobials since the standard blood culture-based diagnostic methods remain time-consuming for the pathogen's identification. Consequently, the routine use of these antibiotics may lead to downstream antimicrobial resistance and failure in treatment outcomes. Recently, significant advances have been made in improving several methodologies for the identification of pathogens directly in whole blood especially regarding specificity and time to detection. Nevertheless, for the widespread implementation of these novel methods in healthcare facilities, further improvements are still needed concerning the sensitivity and cost-effectiveness to allow a faster and more appropriate antimicrobial therapy. This review is focused on the problem of BSIs and sepsis addressing several aspects like their origin, challenges, and causative agents. Also, it highlights current and emerging diagnostics technologies, discussing their strengths and weaknesses.

Evaluation of 11 DNA Automated Extraction Protocols for the Detection of the 5 Mains Candida Species from Artificially Spiked Blood

The molecular detection of Candida plays an important role in the diagnosis of candidaemia, a major cause of morbidity and mortality. The sensitivity of this diagnosis is partly related to the efficiency of yeast DNA extraction. In this monocentric study, we investigated the suitability of 11 recent automated procedures for the extraction of low and high amounts of Candida DNA from spiked blood. The efficacy of the DNA extraction procedures to detect Candida spp. in blood samples ranged from 31.4% to 80.6%. The NucliSENS^TM easyMAG^TM procedure was the most efficient, for each species and each inoculum. It significantly outperformed the other procedures at the lower Candida inocula mimicking the clinical setting. This study highlighted a heterogeneity in DNA extraction efficacy between the five main Candida species (Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis and Candida krusei). Up to five automated procedures were appropriate for C. krusei DNA extraction, whereas only one method yielded an appropriate detection of low amount of C. tropicalis. In the era of the syndromic approach to bloodstream infection diagnosis, this evaluation of 11 automated DNA extraction methods for the PCR diagnosis of candidaemia, puts the choice of an appropriate method in routine diagnosis within the reach of laboratories.

Molecular Methods for the Diagnosis of Invasive Candidiasis

Invasive infections caused by members of the genus Candida are on the rise. Especially patients in intensive care units, immunocompromised patients, and those recovering from abdominal surgery are at risk for the development of candidemia or deep-seated candidiasis. Rapid initiation of appropriate antifungal therapy can increase survival rates significantly. In the past, most of these infections were caused by C. albicans, a species that typically is very susceptible to antifungals. However, in recent years a shift towards infections caused by non-albicans species displaying various susceptibly patterns has been observed and the prompt diagnosis of the underlying species has become an essential factor determining the therapeutic outcome. The gold standard for diagnosing invasive candidiasis is blood culture, even though its sensitivity is low and the time required for species identification usually exceeds 48 h. To overcome these issues, blood culture can be combined with other methods, and a large number of tests have been developed for this purpose. The aim of this review was to give an overview on strengths and limitations of currently available molecular methods for the diagnosis of invasive candidiasis.

Novel strategies for rapid identification and susceptibility testing of MRSA

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with adverse clinical outcomes and increased morbidity, mortality, length of hospital stay, and health-care costs. Rapid diagnosis of MRSA infections has been associated with positive impact on clinical outcomes.

AREAS COVERED

We searched relevant papers in PubMed for the last 10 years. In major papers, we scanned the bibliographies to ensure that important articles were included. This review describes screening and diagnostic test methods for MRSA and their analytical performances with a focus on rapid molecular-based assays including those that are on the horizon. Future novel technologies will allow more rapid detection of phenotypic resistance. In the case of whole-genome sequencing, detection of mutations may predict resistance, transmission, and virulence.

EXPERT OPINION

Currently there are many diagnostic options for the detection of MRSA in surveillance and clinical samples. In general, these are highly accurate and have resulted in improvements in targeted management and reduction in hospital or intensive care unit length of stay for both MSSA and MRSA. Impact on mortality has been variable. Promising novel technologies will not only accurately identify pathogens and detect their resistance markers but will allow discovery of virulence determinants that might further affect patient management.

Recent trends in molecular diagnostics of yeast infections: from PCR to NGS

The incidence of opportunistic yeast infections in humans has been increasing over recent years. These infections are difficult to treat and diagnose, in part due to the large number and broad diversity of species that can underlie the infection. In addition, resistance to one or several antifungal drugs in infecting strains is increasingly being reported, severely limiting therapeutic options and showcasing the need for rapid detection of the infecting agent and its drug susceptibility profile. Current methods for species and resistance identification lack satisfactory sensitivity and specificity, and often require prior culturing of the infecting agent, which delays diagnosis. Recently developed high-throughput technologies such as next generation sequencing or proteomics are opening completely new avenues for more sensitive, accurate and fast diagnosis of yeast pathogens. These approaches are the focus of intensive research, but translation into the clinics requires overcoming important challenges. In this review, we provide an overview of existing and recently emerged approaches that can be used in the identification of yeast pathogens and their drug resistance profiles. Throughout the text we highlight the advantages and disadvantages of each methodology and discuss the most promising developments in their path from bench to bedside.

Evaluation of the Magicplex™ Sepsis Real-Time Test for the Rapid Diagnosis of Bloodstream Infections in Adults

Sepsis is a serious health condition worldwide, affecting more than 30 million people globally each year. Blood culture (BC) is generally used to diagnose sepsis because of the low quantity of microbes occurring in the blood during such infections. However, ~50% of bloodstream infections (BSI) give negative BC, this figure being higher for sepsis, which delays the start of appropriate antimicrobial therapy. This prospective study evaluated a multiplex real-time polymerase chain reaction, the MagicplexTM Sepsis test (MP), for the detection of pathogens from whole blood, comparing it to routine BC. We analyzed 809 blood samples from 636 adult patients, with 132/809 (16.3%) of the samples positive for one or more relevant microorganism according to BC and/or MP. The sensitivity and specificity of MP were 29 and 95%, respectively, while the level of agreement between BC and MP was 87%. The rate of contaminated samples was higher for BC (10%) than MP (4.8%) (P < 0.001). Patients with only MP-positive samples were more likely to be on antimicrobial treatment (47%) than those with only BC-positive samples (18%) (P = 0.002). In summary, the MP test could be useful in some clinical setting, such as among patients on antibiotic therapy. Nevertheless, a low sensitivity demonstrated impairs its use as a part of a routine diagnostic algorithm.

A review of novel technologies and techniques associated with identification of bloodstream infection etiologies and rapid antimicrobial genotypic and quantitative phenotypic determination

INTRODUCTION

The antimicrobial aspect of management of patients with blood stream infections (BSI) and sepsis is time critical. In an era of increasing antimicrobial resistance, rapid detection and identification of bacteria with antimicrobial susceptibility is crucial to direct therapy early in the course of illness. Molecular techniques offer a potential solution to this. Areas covered: In the present review the authors have discussed a number of novel solutions utilizing a variety of molecular techniques for pathogen detection, identification and antimicrobial susceptibility. The review is not designed to be an exhaustive literature review covering all diagnostic solutions ever developed, instead the authors have focused on what they have had experience using, evaluating or currently view as new and exciting with potential to revolutionize BSI diagnosis. The authors searched PubMed (Medline) and Google Scholar with terms: BSI, Bacteraemia, Candidaemia, Diagnostics, AST, Rapid, AMR, Novel and Blood Culture. The authors attended recent clinical microbiology technology congresses. Expert commentary: There are multiple exciting novel technologies at differing stages of development with potential to revolutionize diagnosis of BSI. More work is needed as well as a standardized assessment of different platforms in order to better understand the clinical and financial impacts these will have in clinical microbiology laboratories.