Evaluation of the analytical and clinical performance of two RT-PCR based point-of-care tests; Cepheid Xpert® Xpress CoV-2/Flu/RSV plus and SD BioSensor STANDARD™ M10 Flu/RSV/SARS-CoV-2.

BACKGROUND: Rapid and accurate detection of viral respiratory infections is important for infection control measures. This study compares the analytical and clinical performance of the Xpert® Xpress CoV-2/Flu/RSV plus test ("Xpert", Cepheid) and the STANDARD™ M10 Flu/RSV/SARS-CoV-2 test ("M10", SD Biosensor). Both tests are quadruplex RT-PCR assays for rapid diagnosis of SARS-CoV-2, influenza A/B and RSV. STUDY DESIGN: Analytical sensitivities were determined by limit of detection for SARS-CoV-2, influenza A, influenza B and RSV, respectively. Additionally, the clinical performance of the Xpert and the M10 tests was evaluated against standard-of-care RT-PCR by testing of 492 clinical specimens. RESULTS: The analytical sensitivities for Xpert versus M10 test was 10, 50, 50 and 300 versus 300, 200, 800 and 1500 copies/mL for SARS-CoV-2, influenza A, influenza B and RSV, respectively. Clinical sensitivity for the Xpert test was superior across all four pathogens compared to the M10 test. Xpert showed clinical sensitivity of 100 % in all Ct-ranges for all four pathogens whereas M10 showed clinical sensitivity of 100 % in the 25-30 Ct-range, 84-100 % in the 30-35 Ct-range and 47-67 % in the >35 Ct-range across the four pathogens. Translating into real-life clinical sensitivity, the Xpert would detect 100 % of all four pathogens, whereas M10 would detect 92.1, 92.4, 84.8 and 94.7 % for SARS-CoV-2, influenza A, influenza B and RSV. CONCLUSION: This study demonstrates improved analytical and clinical performance of Xpert Xpress CoV-2/Flu/RSV plus compared to STANDARD M10 Flu/RSV/SARS-CoV-2, which is important for ensuring accuracy of diagnosis at all stages of a respiratory infection.

Highly multiplexed targeted sequencing strategy for infectious disease surveillance.

BACKGROUND: Global efforts to characterize diseases of poverty are hampered by lack of affordable and comprehensive detection platforms, resulting in suboptimal allocation of health care resources and inefficient disease control. Next generation sequencing (NGS) can provide accurate data and high throughput. However, shotgun and metagenome-based NGS approaches are limited by low concentrations of microbial DNA in clinical samples, requirements for tailored sample and library preparations plus extensive bioinformatics analysis. Here, we adapted molecular inversion probes (MIPs) as a cost-effective target enrichment approach to characterize microbial infections from blood samples using short-read sequencing. We designed a probe panel targeting 2 bacterial genera, 21 bacterial and 6 fungi species and 7 antimicrobial resistance markers (AMRs). RESULTS: Our approach proved to be highly specific to detect down to 1 in a 1000 pathogen DNA targets contained in host DNA. Additionally, we were able to accurately survey pathogens and AMRs in 20 out of 24 samples previously profiled with routine blood culture for sepsis. CONCLUSIONS: Overall, our targeted assay identifies microbial pathogens and AMRs with high specificity at high throughput, without the need for extensive sample preparation or bioinformatics analysis, simplifying its application for characterization and surveillance of infectious diseases in medium- to low- resource settings.

Evaluation of four laboratory-based high-throughput SARS-CoV-2 automated antigen tests compared to RT-PCR on nasal and oropharyngeal samples.

BACKGROUND: The demand for RT-PCR testing has been unprecedented during the SARS-CoV-2 pandemic. Fully automated antigen tests (AAT) are less cumbersome than RT-PCR, but data on performance compared to RT-PCR are scarce. METHODS: The study consists of two parts. A retrospective analytical part, comparing the performance of four different AAT on 100 negative and 204 RT-PCR positive deep oropharyngeal samples divided into four groups based on RT-PCR cycle of quantification levels. In the prospective clinical part, 206 individuals positive for and 199 individuals negative for SARS-CoV-2 were sampled from either the anterior nasal cavity (mid-turbinate) or by deep oropharyngeal swabs or both. The performance of AATs was compared to RT-PCR. RESULTS: The overall analytical sensitivity of the AATs differed significantly from 42% (95% CI 35-49) to 60% (95% CI 53-67) with 100% analytical specificity. Clinical sensitivity of the AATs differed significantly from 26% (95% CI 20-32) to 88% (95% CI 84-93) with significant higher sensitivity for mid-turbinate nasal swabs compared to deep oropharyngeal swabs. Clinical specificity varied from 97% to 100%. CONCLUSION: All AATs were highly specific for detection of SARS-CoV-2. Three of the four AATs were significantly more sensitive than the fourth AAT both in terms of analytical and clinical sensitivity. Anatomical test location significantly influenced the clinical sensitivity of AATs.

Emergence of circulating influenza A H3N2 viruses with genetic drift in the matrix gene: be alert of false-negative test results.

In March 2022, we observed samples with a negative fluorescent signal (60.5%, n = 43) for the influenza A matrix gene and a stronger positive signal for subtype A(H3N2). Forty-three samples were positive in InfA (H3N2) (mean Cq 30.9, range 23.9-35.1), and 26 of the 43 samples were negative in InfA matrix (mean Cq 28.0, range 23.2-30.6). Our multiplex test is a laboratory-developed four-target, four-color influenza A reverse-transcription PCR assay targeting the matrix gene, subtypes A(H3N2) and A(H1N1)pdm09. Several samples were negative when retested on commercial influenza Point-of-Care assays. As the matrix gene is a stand-alone target in most commercial diagnostic assays, we caution against false-negative subtype A test results.

Detection of SARS-CoV-2 in exhaled breath from non-hospitalized COVID-19-infected individuals.

The diagnosis of COVID-19 is based on detection of SARS-CoV-2 in oro-/nasopharyngel swabs, but due to discomfort and minor risk during the swab procedure, detection of SARS-CoV-2 has been investigated in other biological matrixes. In this proof-of-concept study, individuals with confirmed SARS-CoV-2 infection performed a daily air sample for five days. Air samples were obtained through a non-invasive electrostatic air sampler. Detection of SARS-CoV-2 RNA was determined with qRT-PCR. The association of positive samples with different exposures was evaluated through mixed-effect models. We obtained 665 air samples from 111 included participants with confirmed SARS-CoV-2 infection. Overall, 52 individuals (46.8%) had at least one positive air sample, and 129 (19.4%) air samples were positive for SARS-CoV-2. Participants with symptoms or a symptom duration ≤ four days had significantly higher odds of having a positive air sample. Cycle threshold values were significantly lower in samples obtained ≤ 4 days from symptom onset. Neither variant of SARS-CoV-2 nor method of air sampling were associated with a positive air sample. We demonstrate that SARS-CoV-2 is detectable in human breath by electrostatic air sampling with the highest detection rate closest to symptom onset. We suggest further evaluation of the air sampling technique to increase sensitivity.

A nationwide analytical and clinical evaluation of 44 rapid antigen tests for SARS-CoV-2 compared to RT-qPCR.

BACKGROUND: The SARS-CoV-2 pandemic has resulted in massive testing by Rapid Antigen Tests (RAT) without solid independent data regarding clinical performance being available. Thus, decision on purchase of a specific RAT may rely on manufacturer-provided data and limited peer-reviewed data. METHODS: This study consists of two parts. In the retrospective analytical part, 33 RAT from 25 manufacturers were compared to RT-PCR on 100 negative and 204 positive deep oropharyngeal cavity samples divided into four groups based on RT-PCR Cq levels. In the prospective clinical part, nearly 200 individuals positive for SARS-CoV-2 and nearly 200 individuals negative for SARS-CoV-2 by routine RT-PCR testing were retested within 72 h for each of 44 included RAT from 26 manufacturers applying RT-PCR as the reference method. RESULTS: The overall analytical sensitivity differed significantly between the 33 included RAT; from 2.5% (95% CI 0.5-4.8) to 42% (95% CI 35-49). All RAT presented analytical specificities of 100%. Likewise, the overall clinical sensitivity varied significantly between the 44 included RAT; from 2.5% (95% CI 0.5-4.8) to 94% (95% CI 91-97). All RAT presented clinical specificities between 98 and 100%. CONCLUSION: The study presents analytical as well as clinical performance data for 44 commercially available RAT compared to the same RT-PCR test. The study enables identification of individual RAT that has significantly higher sensitivity than other included RAT and may aid decision makers in selecting between the included RAT. FUNDING: The study was funded by a participant fee for each test and the Danish Regions.

An Agreement of Antigen Tests on Oral Pharyngeal Swabs or Less Invasive Testing With Reverse Transcription Polymerase Chain Reaction for Detecting SARS-CoV-2 in Adults: Protocol for a Prospective Nationwide Observational Study.

BACKGROUND: The SARS-CoV-2 pandemic has resulted in an unprecedented level of worldwide testing for epidemiologic and diagnostic purposes, and due to the extreme need for tests, the gold-standard Reverse Transcription Polymerase Chain Reaction (RT-PCR) testing capacity has been unable to meet the overall worldwide testing demand. Consequently, although the current literature has shown the sensitivity of rapid antigen tests (RATs) to be inferior to RT-PCR, RATs have been implemented on a large scale without solid data on performance. OBJECTIVE: This study will compare analytical and clinical sensitivities and specificities of 50 lateral flow- or laboratory-based RATs and 3 strand invasion-based amplification (SIBA)-RT-PCR tests from 30 manufacturers to RT-PCR testing of samples obtained from the deep oropharynx. In addition, the study will compare sensitivities and specificities of the included RATs as well as RT-PCR on clinical samples obtained from the deep oropharynx, the anterior nasal cavity, saliva, the deep nasopharynx, and expired air to RT-PCR on deep oropharyngeal samples. METHODS: In the prospective part of the study, 200 individuals found SARS-CoV-2 positive and 200 individuals found SARS-CoV-2 negative by routine RT-PCR testing will be retested with each RAT, applying RT-PCR as the reference method. In the retrospective part of the study, 304 deep oropharyngeal cavity swabs divided into 4 groups based on RT-PCR quantification cycle (Cq) levels will be tested with each RAT. RESULTS: The results will be reported in several papers with different aims. The first paper will report retrospective (analytical sensitivity, overall and stratified into different Cq range groups) and prospective (clinical sensitivity) data for RATs, with RT-PCR as the reference method. The second paper will report results for RAT based on anatomical sampling location. The third paper will compare different anatomical sampling locations by RT-PCR testing. The fourth paper will focus on RATs that rely on central laboratory testing. Tests from 4 different manufacturers will be compared for analytical performance data on retrospective deep oropharyngeal swab samples. The fifth paper will report the results of 4 RATs applied both as professional use and as self-tests. The last paper will report the results from 2 breath tests in the study. A comparison of sensitivity and specificity between RATs will be conducted using the McNemar test for paired samples and the chi-squared test for unpaired samples. Comparison of the positive predictive value (PPV) and negative predictive value (NPV) between RATs will be performed by the bootstrap test, and 95% CIs for sensitivity, specificity, PPV, and NPV will be calculated as bootstrap CIs. CONCLUSIONS: The study will compare the sensitivities of a large number of RATs for SARS-CoV-2 to with those of RT-PCR and will address whether lateral flow-based RATs differ significantly from laboratory-based RATs. The anatomical test locations for both RATs and RT-PCR will also be compared. TRIAL REGISTRATION: ClinicalTrials.gov NCT04913116; https://clinicaltrials.gov/ct2/show/NCT04913116. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/35706.

SARS-CoV-2 detection using reverse transcription strand invasion based amplification and a portable compact size instrument.

Rapid nucleic-acid based tests that can be performed by non-professionals outside laboratory settings could help the containment of the pandemic SARS-CoV-2 virus and may potentially prevent further widespread lockdowns. Here, we present a novel compact portable detection instrument (the Egoo Health System) for extraction-free detection of SARS-CoV-2 using isothermal reverse transcription strand invasion based amplification (RT-SIBA). The SARS-CoV-2 RT-SIBA assay can be performed directly on crude oropharyngeal swabs without nucleic acid extraction with a reaction time of 30 min. The Egoo Health system uses a capsule system, which is automatically sealed tight in the Egoo instrument after applying the sample, resulting in a closed system optimal for molecular isothermal amplification. The performance of the Egoo Health System is comparable to the PCR instrument with an analytical sensitivity of 25 viral RNA copies per SARS-CoV-2 RT-SIBA reaction and a clinical sensitivity and specificity between 87.0-98.4% and 96.6-98.2% respectively.

Point of care testing for infectious disease: ownership and quality.

Traditionally, diagnosis of acute infections has been organism-growth based, which makes timely and actionable infection diagnosis a major challenge. In addition, traditional microbial detection methods, including direct microscopy, are not suited for outsourcing to clinical, non-laboratory-educated personnel. Optimal management of patients with known or suspected clinical infections, such as targeted (or no) antimicrobial treatment and correct use of single room contact isolation facilities, requires rapid identification of the causative infectious microorganism. We are now facing a new disruptive paradigm shift in diagnostic microbiology. The availability of small-footprint robust instruments with easy-to-use assay kits allows non-laboratory-trained nurses and physicians to perform high-quality molecular diagnostics in a near-patient setting with results available in <30 minutes. This technology is currently breaking the centralized laboratory monopoly on the delivery of gold-standard clinical microbiology diagnostics. There is clear potential for huge positive impacts on clinical patient management and antibiotic stewardship, especially in settings where access to timely laboratory test results is not possible, but there are also potentially huge risks. Moving diagnostic testing away from the controlled diagnostic laboratory environment will lead to risks such as increased risk of inappropriate use of the diagnostic tests, insufficient training of staff performing the tests, incorrect interpretation of the test results, lack of quality control procedures, failure to capture test results in electronic patient records and compromised local as well as national surveillance. To reap the upside and avoid the downside of point-of-care infectious disease testing, the diagnostic laboratory needs to maintain oversight, and each institution must have a clear strategy for implementation and execution. If we fail, the risks could outweigh the benefits.

Spotlight influenza: Influenza surveillance before and after the introduction of point-of-care testing in Denmark, season 2014/15 to 2018/19.

BackgroundIn Denmark, influenza surveillance is ensured by data capturing from existing population-based registers. Since 2017, point-of-care (POC) testing has been implemented outside the regional clinical microbiology departments (CMD).AimWe aimed to assess influenza laboratory results in view of the introduction of POC testing.MethodsWe retrospectively observed routine surveillance data on national influenza tests before and after the introduction of POC testing as available in the Danish Microbiological Database. Also, we conducted a questionnaire study among Danish CMD about influenza diagnostics.ResultsBetween the seasons 2014/15 and 2018/19, 199,744 influenza tests were performed in Denmark of which 44,161 were positive (22%). After the introduction of POC testing, the overall percentage of positive influenza tests per season did not decrease. The seasonal influenza test incidence was higher in all observed age groups. The number of operating testing platforms placed outside a CMD and with an instrument analytical time ≤ 3 h increased after 2017. Regionally, the number of tests registered as POC in the Danish Microbiological Database and the number of tests performed with an instrument analytical time ≤ 3 h or outside a CMD partially differed. Where comparable (71% of tests), the relative proportion of POC tests out of all tests increased from season 2017/18 to 2018/19. In both seasons, the percentage of positive POC tests resulted slightly lower than for non-POC tests.ConclusionPOC testing integrated seamlessly into national influenza surveillance. We propose the use of POC results in the routine surveillance of seasonal influenza.

A non-enzymatic, isothermal strand displacement and amplification assay for rapid detection of SARS-CoV-2 RNA.

The current nucleic acid signal amplification methods for SARS-CoV-2 RNA detection heavily rely on the functions of biological enzymes which imposes stringent transportation and storage conditions, high cost and global supply shortages. Here, a non-enzymatic whole genome detection method based on a simple isothermal signal amplification approach is developed for rapid detection of SARS-CoV-2 RNA and potentially any types of nucleic acids regardless of their size. The assay, termed non-enzymatic isothermal strand displacement and amplification (NISDA), is able to quantify 10 RNA copies.µL-1. In 164 clinical oropharyngeal RNA samples, NISDA assay is 100 % specific, and it is 96.77% and 100% sensitive when setting up in the laboratory and hospital, respectively. The NISDA assay does not require RNA reverse-transcription step and is fast (<30 min), affordable, highly robust at room temperature (>1 month), isothermal (42 °C) and user-friendly, making it an excellent assay for broad-based testing.

An in-well direct lysis method for rapid detection of SARS-CoV-2 by real time RT-PCR in eSwab specimens.

BACKGROUND: Diagnostic real time reverse transcription PCR (rRT-PCR) is usually done using nucleic acid (NA) purified from the sample. In the SARS-CoV-2 pandemic reagents and utensils for NA purification has been in short supply. This has generated interest in methods that eliminate the need for NA purification. OBJECTIVES: To investigate if addition of detergent to rRT-PCR master mix (MM) enabled in-well direct lysis and detection of SARS-CoV-2 in clinical eSwab specimens. STUDY DESIGN: IGEPAL-CA-630 (IGEPAL) was added to SARS-CoV-2 MM to 0.3 % final concentration and crude sample was added directly to the PCR well containing MM. Cycle of positivity (Cp) and categorical agreement was compared in samples tested in standard rRT-PCR after NA purification and in in-well lysis, direct rRT-PCR. RESULTS: In-well lysis direct rRT-PCR detected SARS-CoV-2 in 27/30 previously SARS-CoV-2+ samples with an average bias of 3.26 cycles (95 %CI: 0.08-6.43 cycles). All 30 previously test negative samples remained negative when tested in in-well lysis, direct PCR. CONCLUSIONS: Supplementation of detergent to MM was shown to be useful for the detection of SARS CoV-2 in eSwab specimens (COPAN) by direct rRT-PCR without prior NA purification.

Point-of-care tests for influenza A and B viruses and RSV in emergency departments - indications, impact on patient management and possible gains by syndromic respiratory testing, Capital Region, Denmark, 2018.

BackgroundPoint-of-care tests (POCT) for influenza A and B viruses and respiratory syncytial virus (RSV) were implemented in emergency departments of all hospitals in the Capital Region of Denmark in 2018.AimTo establish whether POC testing for influenza viruses or RSV is based on a valid respiratory symptom indication, whether changes in patient management based on a positive result are safe and whether syndromic POC testing may benefit patients with influenza or RSV.MethodsSamples from 180 children (< 18 years) and 375 adults tested using POCT between February and July 2018 were retested for 26 respiratory pathogens. Diagnosis, indication for POC testing, hospitalisation time, antimicrobial therapy and readmission or death within one month of testing were obtained from patient records.ResultsA valid indication for POC testing was established in 168 (93.3%) of children and 334 (89.1%) of adults. A positive POCT result significantly reduced antibiotic prescription and median hospitalisation time by 44.3 hours for adults and 14.2 hours for children, and significantly increased antiviral treatment in adults. Risk of readmission or death was not significantly altered by a positive result. Testing for 26 respiratory pathogens established that risk of coinfection is lower with increasing age and that POCT for adults should be restricted to the influenza and RSV season.ConclusionPositive POCT resulted in changed patient management for both children and adults, and was deemed safe. POCT for additional pathogens may be beneficial in children below 5 years of age and outside the influenza and RSV season.

Streptococcal toxic shock syndrome in a patient with community-acquired pneumonia. Impact of rapid diagnostics on patient management.

Here we describe a community-acquired pneumonia with Streptococcus pyogenes , group A following a common cold caused by human metapneumovirus. The patient, a 58-year-old woman with no prior medical history, developed respiratory failure and multi-organ dysfunction caused by streptococcal toxic shock syndrome. The patient was admitted to the intensive care unit and treated with supportive care. The definitive diagnosis was made by BioFire FilmArray by Biomerieux (multiplex PCR) 12 h before positive blood culture, thus enabling the clinician to add clindamycin and intravenous immunoglobulin to the treatment. The patient was discharged fully recovered after 23 days. Streptococci group A is a rare pathogen of severe pneumonia and rapid diagnostics by syndromic testing, potentially performed in a near patient setting, is crucial for early implementation of targeted antimicrobial treatment.

Multicenter Evaluation of the QIAstat-Dx Respiratory Panel for Detection of Viruses and Bacteria in Nasopharyngeal Swab Specimens.

The QIAstat-Dx Respiratory Panel (QIAstat-Dx RP) is a multiplex in vitro diagnostic test for the qualitative detection of 20 pathogens directly from nasopharyngeal swab (NPS) specimens. The assay is performed using a simple sample-to-answer platform with results available in approximately 69 min. The pathogens identified are adenovirus, coronavirus 229E, coronavirus HKU1, coronavirus NL63, coronavirus OC43, human metapneumovirus A and B, influenza A, influenza A H1, influenza A H3, influenza A H1N1/2009, influenza B, parainfluenza virus 1, parainfluenza virus 2, parainfluenza virus 3, parainfluenza virus 4, rhinovirus/enterovirus, respiratory syncytial virus A and B, Bordetella pertussis, Chlamydophila pneumoniae, and Mycoplasma pneumoniae This multicenter evaluation provides data obtained from 1,994 prospectively collected and 310 retrospectively collected (archived) NPS specimens with performance compared to that of the BioFire FilmArray Respiratory Panel, version 1.7. The overall percent agreement between QIAstat-Dx RP and the comparator testing was 99.5%. In the prospective cohort, the QIAstat-Dx RP demonstrated a positive percent agreement of 94.0% or greater for the detection of all but four analytes: coronaviruses 229E, NL63, and OC43 and rhinovirus/enterovirus. The test also demonstrated a negative percent agreement of ≥97.9% for all analytes. The QIAstat-Dx RP is a robust and accurate assay for rapid, comprehensive testing for respiratory pathogens.

Multicenter evaluation of the QIAstat Respiratory Panel-A new rapid highly multiplexed PCR based assay for diagnosis of acute respiratory tract infections.

Acute respiratory tract infections (ARTI), including the common cold, pharyngitis, sinusitis, otitis media, bronchiolitis and pneumonia are the most common diagnoses among patients seeking medical care in western countries, and account for most antibiotic prescriptions. While a confirmed and fast ARTI diagnosis is key for antibiotic prescribing, empiric antimicrobial treatment remains common, because viral symptoms are often clinically similar and difficult to distinguish from those caused by bacteria. As a result, inappropriate antibiotic prescriptions are high and in certain settings likely higher than the commonly estimated 30%. The QIAstat Respiratory Panel® assay (QIAstat RP) is a multiplexed in vitro diagnostics test for the rapid simultaneous detection of 21 pathogens directly from respiratory samples, including human mastadenovirus A-G, primate bocaparvovirus 1+2, human coronavirus (HKU1, NL63, OC43, 229E), human metapneumovirus A/B, rhinovirus/enterovirus, influenza A virus (no subtype, subtype H1, H1N1/2009, H3), influenza B virus, human respirovirus 1+3, human orthorubulavirus 2+4, human orthopneumovirus, Bordetella pertussis, Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila. We describe the first multicenter study of 445 respiratory samples, collected through the 2016-2017 and 2018 respiratory seasons, with performance compared against BioFire FilmArray RP v1.7 and discrepancy testing by Seegene Allplex RP. The QIAstat RP demonstrated a positive percentage of agreement of 98.0% (95% CI: 96.0-99.1%) and a negative percentage agreement of 99.8% (95% CI: 99.6-99.9%). With use of this comprehensive and rapid test, improved patient outcomes and antimicrobial stewardship may potentially be achieved.

Multicenter evaluation of the new QIAstat Gastrointestinal Panel for the rapid syndromic testing of acute gastroenteritis.

In acute gastroenteritis (AGE), identification of the infectious agent is important for patient management. Since symptoms do not reliably identify the agent, microbiological diagnostics are important. Conventional methods lack sensitivity and often take days. Multiplex PCR panels offer fast and sensitive alternatives. Our aim was to assess the performance of the new QIAstat Gastrointestinal Panel (GIP) detecting 24 different gastroenteric pathogens from stool in Cary-Blair transport medium (Adenovirus F 40/41, Astrovirus, Norovirus GI/GII, Rotavirus A, Sapovirus, Campylobacter spp., Clostridium difficile, Plesiomonas shigelloides, Salmonella spp., Vibrio cholera, Vibrio parahaemolyticus, Vibrio vulnificus, Yersinia enterocolitica, enteroaggregative Escherichia coli, enteropathogenic E. coli, enterotoxigenic E. coli, Shiga-toxin-producing E. coli (stx1 and stx2) (including specific detection of E. coli O157), Shigella spp./enteroinvasive E. coli, Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica and Giardia lamblia). We tested both prospective (n = 163) and retrospective (n = 222) stool samples sent for routine diagnostics by the QIAstat GIP comparing it to the FDA-approved BioFire FilmArray GIP. Seegene Allplex GIP was used for discrepancy testing. After discrepancy testing, QIAstat GIP detected 447 of 455 pathogens (98.2%, 95% confidence interval (CI) 96.6-99.1%). There were eight false positive detections. Multiple pathogens were detected in 32.5% of positive samples. The QIAstat GIP detected a large range of AGE pathogens with a high sensitivity. It offers an easy-to-use system for GI pathogen detection in stool within 70 min. An advantage of the QIAstat is the availability of cycle threshold (CT) values to aid in interpretation of results.

Developmental roadmap for antimicrobial susceptibility testing systems.

Antimicrobial susceptibility testing (AST) technologies help to accelerate the initiation of targeted antimicrobial therapy for patients with infections and could potentially extend the lifespan of current narrow-spectrum antimicrobials. Although conceptually new and rapid AST technologies have been described, including new phenotyping methods, digital imaging and genomic approaches, there is no single major, or broadly accepted, technological breakthrough that leads the field of rapid AST platform development. This might be owing to several barriers that prevent the timely development and implementation of novel and rapid AST platforms in health-care settings. In this Consensus Statement, we explore such barriers, which include the utility of new methods, the complex process of validating new technology against reference methods beyond the proof-of-concept phase, the legal and regulatory landscapes, costs, the uptake of new tools, reagent stability, optimization of target product profiles, difficulties conducting clinical trials and issues relating to quality and quality control, and present possible solutions.

A 5' Nuclease Genotyping Assay for Identification of Macrolide-Resistant Mycoplasma genitalium in Clinical Specimens.

Rapid and sensitive detection of macrolide resistance in Mycoplasma genitalium is required for the guidance of adequate antimicrobial treatment. Previous studies have confirmed that single-base mutations at position 2058 or 2059 in domain V of the 23S rRNA gene of M. genitalium result in high-level macrolide resistance. Sequencing of PCR products remains the gold standard for the identification of mutations conferring resistance to macrolides but is laborious and time-consuming. The aim of the present study was to develop a 5' nuclease genotyping assay to detect single nucleotide polymorphisms in the 23S rRNA gene of Mycoplasma genitalium that are associated with macrolide resistance by combining PCR with hydrolysis probes and subsequent endpoint genotyping analysis. The 5' nuclease genotyping assay was used as a referral test to be used on M. genitalium-positive samples and was validated on 259 positive samples, of which 253 (97.7%) were successfully sequenced. With the newly developed assay, 237/259 (91.5%) investigated M. genitalium-positive samples were genotyped. The positive and the negative predictive values were 100% when evaluated on successfully genotyped samples. The newly developed assay discriminated macrolide-resistant M. genitalium in clinical specimens possessing A2058G, A2058C, A2058T, and A2059G mutations with a sensitivity of 94.4% (95% confidence interval [CI], 90.7% to 98.2%) and a specificity of 92.7% (95% CI, 87.8% to 97.6%) when evaluated on successfully sequenced samples. The assay can correctly guide antimicrobial treatment of M. genitalium infections.

[Epidemic increase in methicillin-resistant Staphylococcus aureus in Copenhagen]. / Epidemisk stigning af methicillinresistente Staphylococcus aureus i København.

INTRODUCTION: We have found an epidemic increase in methicillin-resistant Staphylococcus aureus (MRSA) in Copenhagen. The increase has a complex background and involves hospitals, nursing homes and persons nursed in their own home. MATERIAL AND METHODS: We found 33 MRSA patients in 2003 and 121 in 2004. All isolates have been spa-typed and epidemiologic information collected. RESULTS: The number of MRSA cases has a doubling time of about six months. The epidemic has been caused by many different MRSA types and 31 staphylococcus protein A genotypes (spa types). MRSA has caused several hospital outbreaks and is endemic in 10 nursing homes. Five staff members from nursing homes have been infected with MRSA. MRSA commonly causes skin and soft tissue infections (76%), but serious infections such as septicaemia and pneumonia are also found. CONCLUSION: Treatment of MRSA-infected patients is costly due to isolation regimes, increase in bed-days and treatment with special antibiotics. After treatment of the infection and in cases of MRSA carriage, MRSA is found on the skin and in the nose. Carriage of MRSA can be eradicated by washing with chlorhexidine and nasal administration of mupirocin. The necessary resources for handling the epidemic are not available. Without active intervention, this situation will have serious implications for the health care system.