Expert guidance on target product profile development for AMR diagnostic tests.

Diagnostics are widely considered crucial in the fight against antimicrobial resistance (AMR), which is expected to kill 10 million people annually by 2030. Nevertheless, there remains a substantial gap between the need for AMR diagnostics versus their development and implementation. To help address this problem, target product profiles (TPP) have been developed to focus developers' attention on the key aspects of AMR diagnostic tests. However, during discussion between a multisectoral working group of 51 international experts from industry, academia and healthcare, it was noted that specific AMR-related TPPs could be extended by incorporating the interdependencies between the key characteristics associated with the development of such TPPs. Subsequently, the working group identified 46 characteristics associated with six main categories (ie, Intended Use, Diagnostic Question, Test Description, Assay Protocol, Performance and Commercial). The interdependencies of these characteristics were then identified and mapped against each other to generate new insights for use by stakeholders. Specifically, it may not be possible for diagnostics developers to achieve all of the recommendations in every category of a TPP and this publication indicates how prioritising specific TPP characteristics during diagnostics development may influence (or not) a range of other TPP characteristics associated with the diagnostic. The use of such guidance, in conjunction with specific TPPs, could lead to more efficient AMR diagnostics development.

Technologies for Diabetes Self-Monitoring: A Scoping Review and Assessment Using the REASSURED Criteria.

BACKGROUND: Self-management is an important pillar for diabetes control and to achieve it, glucose self-monitoring devices are needed. Currently, there exist several different devices in the market and many others are being developed. However, whether these devices are suitable to be used in resource constrained settings is yet to be evaluated. AIMS: To assess existing glucose monitoring tools and also those in development against the REASSURED which have been previously used to evaluate diagnostic tools for communicable diseases. METHODS: We conducted a scoping review by searching PubMed for peer-review articles published in either English, Spanish or Portuguese in the last 5 years. We selected papers including information about devices used for self-monitoring and tested on humans with diabetes; then, the REASSURED criteria were used to assess them. RESULTS: We found a total of 7 continuous glucose monitoring device groups, 6 non-continuous, and 6 devices in development. Accuracy varied between devices and most of them were either invasive or minimally invasive. Little to no evidence is published around robustness, affordability and delivery to those in need. However, when reviewing publicly available prices, none of the devices would be affordable for people living in low- and middle-income countries. CONCLUSIONS: Available devices cannot be considered adapted for use in self-monitoring in resource constraints settings. Further studies should aim to develop less-invasive devices that do not require a large set of components. Additionally, we suggest some improvement in the REASSURED criteria such as the inclusion of patient-important outcomes to increase its appropriateness to assess non-communicable diseases devices.

Development of a target product profile for a point-of-care cardiometabolic device.

INTRODUCTION: Multi-parameter diagnostic devices can simplify cardiometabolic disease diagnosis. However, existing devices may not be suitable for use in low-resource settings, where the burden of non-communicable diseases is high. Here we describe the development of a target product profile (TPP) for a point-of-care multi-parameter device for detection of biomarkers for cardiovascular disease and metabolic disorders, including diabetes, in primary care settings in low- and middle-income countries (LMICs). METHODS: A draft TPP developed by an expert group was reviewed through an online survey and semi-structured expert interviews to identify device characteristics requiring refinement. The draft TPP included 41 characteristics with minimal and optimal requirements; characteristics with an agreement level for either requirement of ≤ 85% in either the survey or among interviewees were further discussed by the expert group and amended as appropriate. RESULTS: Twenty people responded to the online survey and 18 experts participated in the interviews. Twenty-two characteristics had an agreement level of ≤ 85% in either the online survey or interviews. The final TPP defines the device as intended to be used for basic diagnosis and management of cardiometabolic disorders (lipids, glucose, HbA1c, and creatinine) as minimal requirement, and offering an expanded test menu for wider cardiometabolic disease management as optimal requirement. To be suitable, the device should be intended for level 1 healthcare settings or lower, used by minimally trained healthcare workers and allow testing using self-contained cartridges or strips without the need for additional reagents. Throughput should be one sample at a time in a single or multi-analyte cartridge, or optimally enable testing of several samples and analytes in parallel with random access. CONCLUSION: This TPP will inform developers of cardiometabolic multi-parameter devices for LMIC settings, and will support decision makers in the evaluation of existing and future devices.

HIV self-testing with digital supports as the new paradigm: A systematic review of global evidence (2010-2021).

BACKGROUND: HIV self-testing (HIVST) is recommended by the WHO as an innovative strategy to reach UNAIDS targets to end HIV by 2030. HIVST with digital supports is defined as the use of digital interventions (e.g., website-based, social media, mobile HIVST applications (apps), text messaging (SMS), digital vending machines (digital VMs)) to improve the efficiency and impact of HIVST. HIVST deployment and integration in health services is an emerging priority. We conducted a systematic review aiming to close the gap in evidence that summarizes the impact of digitally supported HIVST and to inform policy recommendations. METHODS: We searched PubMed and Embase for articles and abstracts on HIVST with digital supports published during the period February 1st, 2010 to June 15th, 2021, following Cochrane guidelines and PRISMA methodology. We assessed feasibility, acceptability, preference, and impact outcomes across all populations and study designs. Metrics reported were willingness to use HIVST, preferences for HIVST delivery, proportion of first-time testers, HIVST uptake, HIVST kit return rate, and linkage to care. Heterogeneity of the interventions and reported metrics precluded us from conducting a meta-analysis. FINDINGS: 46 studies were narratively synthesized, of which 72% were observational and 28% were RCTs. Half of all studies (54%, 25/46) assessed web-based innovations (e.g., study websites, videos, chatbots), followed by social media (26%, 12/46), HIVST-specific apps (7%, 3/46), SMS (9%, 4/46), and digital VMs (4%, 2/46). Web-based innovations were found to be acceptable (77-97%), preferred over in-person and hybrid options by more first-time testers (47-48%), highly feasible (93-95%), and were overall effective in supporting linkage to care (53-100%). Social media and app-based innovations also had high acceptability (87-95%) and linkage to care proportions (80-100%). SMS innovations increased kit return rates (54-94%) and HIVST uptake among hard-to-reach groups. Finally, digital VMs were highly acceptable (54-93%), and HIVST uptake was six times greater when using digital VMs compared to distribution by community workers. INTERPRETATION: HIVST with digital supports was deemed feasible, acceptable, preferable, and was shown to increase uptake, engage first-time testers and hard-to-reach populations, and successfully link participants to treatment. Findings pave the way for greater use of HIVST interventions with digital supports globally.

Diagnostics and monitoring tools for noncommunicable diseases: a missing component in the global response.

A key component of any health system is the capacity to accurately diagnose individuals. One of the six building blocks of a health system as defined by the World Health Organization (WHO) includes diagnostic tools. The WHO's Noncommunicable Disease Global Action Plan includes addressing the lack of diagnostics for noncommunicable diseases, through multi-stakeholder collaborations to develop new technologies that are affordable, safe, effective and quality controlled, and improving laboratory and diagnostic capacity and human resources. Many challenges exist beyond price and availability for the current tools included in the Package of Essential Noncommunicable Disease Interventions (PEN) for cardiovascular disease, diabetes and chronic respiratory diseases. These include temperature stability, adaptability to various settings (e.g. at high altitude), need for training in order to perform and interpret the test, the need for maintenance and calibration, and for Blood Glucose Meters non-compatible meters and test strips. To date the issues surrounding access to diagnostic and monitoring tools for noncommunicable diseases have not been addressed in much detail. The aim of this Commentary is to present the current landscape and challenges with regards to guidance from the WHO on diagnostic tools using the WHO REASSURED criteria, which define a set of key characteristics for diagnostic tests and tools. These criteria have been used for communicable diseases, but so far have not been used for noncommunicable diseases. Diagnostic tools have played an important role in addressing many communicable diseases, such as HIV, TB and neglected tropical diseases. Clearly more attention with regards to diagnostics for noncommunicable diseases as a key component of the health system is needed.

Electronic clinical decision support algorithms incorporating point-of-care diagnostic tests in low-resource settings: a target product profile.

Health workers in low-resource settings often lack the support and tools to follow evidence-based clinical recommendations for diagnosing, treating and managing sick patients. Digital technologies, by combining patient health information and point-of-care diagnostics with evidence-based clinical protocols, can help improve the quality of care and the rational use of resources, and save patient lives. A growing number of electronic clinical decision support algorithms (CDSAs) on mobile devices are being developed and piloted without evidence of safety or impact. Here, we present a target product profile (TPP) for CDSAs aimed at guiding preventive or curative consultations in low-resource settings. This document will help align developer and implementer processes and product specifications with the needs of end users, in terms of quality, safety, performance and operational functionality. To identify the characteristics of CDSAs, a multidisciplinary group of experts (academia, industry and policy makers) with expertise in diagnostic and CDSA development and implementation in low-income and middle-income countries were convened to discuss a draft TPP. The TPP was finalised through a Delphi process to facilitate consensus building. An agreement greater than 75% was reached for all 40 TPP characteristics. In general, experts were in overwhelming agreement that, given that CDSAs provide patient management recommendations, the underlying clinical algorithms should be human-interpretable and evidence-based. Whenever possible, the algorithm's patient management output should take into account pretest disease probabilities and likelihood ratios of clinical and diagnostic predictors. In addition, validation processes should at a minimum show that CDSAs are implementing faithfully the evidence they are based on, and ideally the impact on patient health outcomes. In terms of operational needs, CDSAs should be designed to fit within clinic workflows and function in connectivity-challenged and high-volume settings. Data collected through the tool should conform to local patient privacy regulations and international data standards.

The effect of empiric antimicrobial treatment duration on detection of bacterial DNA in sterile surgical specimens.

Initial antimicrobial treatment of patients with deep seated or invasive infections is typically empiric. Usually, cultures of specimens obtained from the suspected source of infection are performed to identify pathogens and guide continued antimicrobial treatment. When patients present with signs and symptoms of infection, but sterile body fluid or tissue specimens cannot be obtained in a timely fashion, growth of bacterial pathogens in culture may be inhibited following initiation of empiric antibiotic treatment. To address this clinical dilemma, we performed a prospective evaluation of conventional culture vs. PCR coupled to electrospray ionization mass spectrometry (PCR/ESI-MS) on sterile body fluids and tissues submitted to the diagnostic microbiology lab following initiation of empiric antibiotic treatment for patients with suspected infection. In this series of surgical samples, PCR/ESI-MS identified bacterial pathogen(s) in 56% (49/87) of patients with non-diagnostic cultures. Examination of patients stratified by antibiotic treatment duration demonstrated that PCR/ESI-MS sustains high rates of bacterial DNA detection over time by generalized estimating equation models (p<0.0001).

Informing Antibiotic Treatment Decisions: Evaluating Rapid Molecular Diagnostics To Identify Susceptibility and Resistance to Carbapenems against Acinetobacter spp. in PRIMERS III.

The widespread dissemination of carbapenem-resistant Acinetobacter spp. has created significant therapeutic challenges. At present, rapid molecular diagnostics (RMDs) that can identify this phenotype are not commercially available. Two RMD platforms, PCR combined with electrospray ionization mass spectrometry (PCR/ESI-MS) and molecular beacons (MB), for detecting genes conferring resistance/susceptibility to carbapenems in Acinetobacter spp. were evaluated. An archived collection of 200 clinical Acinetobacter sp. isolates was tested. Predictive values for susceptibility and resistance were estimated as a function of susceptibility prevalence and were based on the absence or presence of beta-lactamase (bla) NDM, VIM, IMP, KPC, and OXA carbapenemase genes (e.g., blaOXA-23, blaOXA-24/40, and blaOXA-58 found in this study) against the reference standard of MIC determinations. According to the interpretation of MICs, 49% (n = 98) of the isolates were carbapenem resistant (as defined by either resistance or intermediate resistance to imipenem). The susceptibility sensitivities (95% confidence interval [CI]) for imipenem were 82% (74%, 89%) and 92% (85%, 97%) for PCR/ESI-MS and MB, respectively. Resistance sensitivities (95% CI) for imipenem were 95% (88%, 98%) and 88% (80%, 94%) for PCR/ESI-MS and MB, respectively. PRIMERS III establishes that RMDs can discriminate between carbapenem resistance and susceptibility in Acinetobacter spp. In the context of a known prevalence of resistance, SPVs and RPVs can inform clinicians regarding the best choice for empiric antimicrobial therapy against this multidrug-resistant pathogen.

Prosthetic Valve Endocarditis Caused by Bartonella henselae: A Case Report of Molecular Diagnostics Informing Nonsurgical Management.

Identifying the pathogen responsible for culture-negative valve endocarditis often depends on molecular studies performed on surgical specimens. A patient with Ehlers-Danlos syndrome who had an aortic graft, a mechanical aortic valve, and a mitral anulloplasty ring presented with culture-negative prosthetic valve endocarditis and aortic graft infection. Research-based polymerase chain reaction (PCR)/electrospray ionization mass spectrometry on peripheral blood samples identified Bartonella henselae. Quantitative PCR targeting the16S-23S ribonucleic acid intergenic region and Western immunoblotting confirmed this result. This, in turn, permitted early initiation of pathogen-directed therapy and subsequent successful medical management of B henselae prosthetic valve endocarditis and aortic graft infection.

The IRIDICA BAC BSI Assay: Rapid, Sensitive and Culture-Independent Identification of Bacteria and Candida in Blood.

UNLABELLED: Bloodstream infection (BSI) and sepsis are rising in incidence throughout the developed world. The spread of multi-drug resistant organisms presents increasing challenges to treatment. Surviving BSI is dependent on rapid and accurate identification of causal organisms, and timely application of appropriate antibiotics. Current culture-based methods used to detect and identify agents of BSI are often too slow to impact early therapy and may fail to detect relevant organisms in many positive cases. Existing methods for direct molecular detection of microbial DNA in blood are limited in either sensitivity (likely the result of small sample volumes) or in breadth of coverage, often because the PCR primers and probes used target only a few specific pathogens. There is a clear unmet need for a sensitive molecular assay capable of identifying the diverse bacteria and yeast associated with BSI directly from uncultured whole blood samples. We have developed a method of extracting DNA from larger volumes of whole blood (5 ml per sample), amplifying multiple widely conserved bacterial and fungal genes using a mismatch- and background-tolerant PCR chemistry, and identifying hundreds of diverse organisms from the amplified fragments on the basis of species-specific genetic signatures using electrospray ionization mass spectrometry (PCR/ESI-MS). We describe the analytical characteristics of the IRIDICA BAC BSI Assay and compare its pre-clinical performance to current standard-of-care methods in a collection of prospectively collected blood specimens from patients with symptoms of sepsis. The assay generated matching results in 80% of culture-positive cases (86% when common contaminants were excluded from the analysis), and twice the total number of positive detections. The described method is capable of providing organism identifications directly from uncultured blood in less than 8 hours. DISCLAIMER: The IRIDICA BAC BSI Assay is not available in the United States.

Rapid Molecular Diagnostics, Antibiotic Treatment Decisions, and Developing Approaches to Inform Empiric Therapy: PRIMERS I and II.

BACKGROUND: Rapid molecular diagnostic (RMD) platforms may lead to better antibiotic use. Our objective was to develop analytical strategies to enhance the interpretation of RMDs for clinicians. METHODS: We compared the performance characteristics of 4 RMD platforms for detecting resistance against ß-lactams in 72 highly resistant isolates of Escherichia coli and Klebsiella pneumoniae (PRIMERS I). Subsequently, 2 platforms were used in a blinded study in which a heterogeneous collection of 196 isolates of E. coli and K. pneumoniae (PRIMERS II) were examined. We evaluated the genotypic results as predictors of resistance or susceptibility against ß-lactam antibiotics. We designed analytical strategies and graphical representations of platform performance, including discrimination summary plots and susceptibility and resistance predictive values, that are readily interpretable by practitioners to inform decision-making. RESULTS: In PRIMERS I, the 4 RMD platforms detected ß-lactamase (bla) genes and identified susceptibility or resistance in >95% of cases. In PRIMERS II, the 2 platforms identified susceptibility against extended-spectrum cephalosporins and carbapenems in >90% of cases; however, against piperacillin/tazobactam, susceptibility was identified in <80% of cases. Applying the analytical strategies to a population with 15% prevalence of ceftazidime-resistance and 5% imipenem-resistance, RMD platforms predicted susceptibility in >95% of cases, while prediction of resistance was 69%-73% for ceftazidime and 41%-50% for imipenem. CONCLUSIONS: RMD platforms can help inform empiric ß-lactam therapy in cases where bla genes are not detected and the prevalence of resistance is known. Our analysis is a first step in bridging the gap between RMDs and empiric treatment decisions.

Rapid Diagnosis of Infection in the Critically Ill, a Multicenter Study of Molecular Detection in Bloodstream Infections, Pneumonia, and Sterile Site Infections.

OBJECTIVE: Early identification of causative microorganism(s) in patients with severe infection is crucial to optimize antimicrobial use and patient survival. However, current culture-based pathogen identification is slow and unreliable such that broad-spectrum antibiotics are often used to insure coverage of all potential organisms, carrying risks of overtreatment, toxicity, and selection of multidrug-resistant bacteria. We compared the results obtained using a novel, culture-independent polymerase chain reaction/electrospray ionization-mass spectrometry technology with those obtained by standard microbiological testing and evaluated the potential clinical implications of this technique. DESIGN: Observational study. SETTING: Nine ICUs in six European countries. PATIENTS: Patients admitted between October 2013 and June 2014 with suspected or proven bloodstream infection, pneumonia, or sterile fluid and tissue infection were considered for inclusion. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We tested 616 bloodstream infection, 185 pneumonia, and 110 sterile fluid and tissue specimens from 529 patients. From the 616 bloodstream infection samples, polymerase chain reaction/electrospray ionization-mass spectrometry identified a pathogen in 228 cases (37%) and culture in just 68 (11%). Culture was positive and polymerase chain reaction/electrospray ionization-mass spectrometry negative in 13 cases, and both were negative in 384 cases, giving polymerase chain reaction/electrospray ionization-mass spectrometry a sensitivity of 81%, specificity of 69%, and negative predictive value of 97% at 6 hours from sample acquisition. The distribution of organisms was similar with both techniques. Similar observations were made for pneumonia and sterile fluid and tissue specimens. Independent clinical analysis of results suggested that polymerase chain reaction/electrospray ionization-mass spectrometry technology could potentially have resulted in altered treatment in up to 57% of patients. CONCLUSIONS: Polymerase chain reaction/electrospray ionization-mass spectrometry provides rapid pathogen identification in critically ill patients. The ability to rule out infection within 6 hours has potential clinical and economic benefits.

Salvage microbiology: opportunities and challenges in the detection of bacterial pathogens following initiation of antimicrobial treatment.

Broad-range 16S ribosomal RNA gene PCR coupled with Sanger sequencing was originally employed by soil scientists and was subsequently adapted for clinical applications. PCR coupled with electrospray ionization mass spectrometry has also progressed from initial applications in the detection of organisms from environmental samples into the clinical realm and has demonstrated promise in detection of pathogens in clinical specimens obtained from patients with suspected infection but negative cultures. We review studies of multiplex PCR, 16S ribosomal RNA gene PCR and sequencing and PCR coupled with electrospray ionization mass spectrometry for detection of bacteria in specimens that were obtained from patients during or after administration of antibiotic treatment, and examine the role of each for assisting in antimicrobial treatment and stewardship efforts. Following an exploration of the available data in this field, we discuss the opportunities that the preliminary investigations reveal, as well as the challenges faced with the implementation of these strategies in clinical practice.

Culture negative empyema in a critically ill child: an opportunity for rapid molecular diagnostics.

BACKGROUND: Nucleic acid amplification technologies (NAAT) are advancing our ability to make rapid molecular diagnoses in patients with serious culture negative infections. This is the first report of PCR coupled to electrospray ionization mass spectrometry use in the evaluation of complicated community acquired pneumonia in a pediatric patient. CASE PRESENTATION: We present a case of culture negative empyema in a critically ill, Caucasian, 2-year-old girl who was treated with broad-spectrum empiric antibiotics, in which the length of stay was prolonged by adverse effects of the empiric antibiotic treatment. PCR coupled to electrospray ionization mass spectrometry was applied to culture negative fluid and tissue samples from the patient in order to determine the etiology of the empyema. CONCLUSIONS: Using this method, Streptococcus mitis/viridans was identified as the pathogen. A retrospective review of cases of empyema in children at our institution found that 87.5% of cases were negative for identification of a pathogen and antibiotics were administered to 100% of cases prior to collecting pleural fluid for culture. Understanding the role of Streptococcus mitis/viridans group in the etiology of empyema using an advanced NAAT coupled with mass spectrometry can enlighten clinicians as to the impact of this pathogen in community acquired pneumonia and help assist with antibiotic stewardship.

Acute respiratory distress caused by Neosartorya udagawae.

We describe the first reported case of acute respiratory distress syndrome (ARDS) attributed to Neosartorya udagawae infection. This mold grew rapidly in cultures of multiple respiratory specimens from a previously healthy 43-year-old woman. Neosartorya spp. are a recently recognized cause of invasive disease in immunocompromised patients that can be mistaken for their sexual teleomorph, Aspergillus fumigatus. Because the cultures were sterile, phenotypic identification was not possible. DNA sequencing of ITS, calmodulin and ß-tubulin genes supported identification of Neosartorya udagawae. Our case is the first report of ARDS associated with Neosartorya sp. infection and defines a new clinical entity.