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147300.9923Evaluation of the Unyvero i60 ITI® multiplex PCR for infected chronic leg ulcers diagnosis. OBJECTIVES: Unyvero i60 ITI multiplex PCR (mPCR) may identify a large panel of bacteria and antibiotic resistance genes. In this study, we compared results obtained by mPCR to standard bacteriology in chronic leg ulcer (CLU) infections. METHODS: A prospective study, part of the interventional-blinded randomized study "ulcerinfecte" (NCT02889926), was conducted at Saint Joseph Hospital in Paris. Fifty patients with a suspicion of infected CLU were included between February 2017 and September 2018. Conventional bacteriology and mPCR were performed simultaneously on deep skin biopsies. RESULTS: Staphylococcus aureus and Pseudomonas aeruginosa were the most detected pathogens. Regarding the global sensitivity, mPCR is not overcome to the standard culture. Anaerobes and slow growing bacteria were detected with a higher sensitivity rate by mPCR than standard culture. CONCLUSION: Unyvero i60 ITI multiplex PCR detected rapidly pathogenic bacteria in infected CLU especially anaerobes and slow growing bacteria and was particularly effective for patients previously treated with antibiotics.202031790779
579510.9909Direct identification of Gram-positive bacteria and resistance determinants from blood cultures using a microarray-based nucleic acid assay: in-depth analysis of microarray data for undetermined results. BACKGROUND: The Verigene Gram-Positive Blood Culture (BC-GP) nucleic acid assay (Nanosphere, Inc., Northbrook, IL, USA) is a newly developed microarray-based test with which 12 Gram-positive bacterial genes and three resistance determinants can be detected using blood culture broths. We evaluated the performance of this assay and investigated the signal characteristics of the microarray images. METHODS: At the evaluation stage, we tested 80 blood cultures that were positive for various bacteria (68 bacteria covered and 12 not covered by the BC-GP panel) collected from the blood of 36 patients and 44 spiked samples. In instances where the automated system failed and errors were called, we manually inspected microarray images, measured the signal intensities of target spots, and reclassified the results. RESULTS: With the manual analysis of the microarray images of 14 samples for which error calls were reported, we could obtain correct identification results for 12 samples without the need for retesting, because strong signals in the target spots were clearly discriminable from background noise. With our interpretation strategy, we could obtain 97.1% sensitivity and 100% specificity for bacterial identification by using the BC-GP assay. The two unidentified bacteria were viridans group streptococci, which produced weaker target signals. During the application stage, among 25 consecutive samples positive for Gram-positive bacteria, we identified two specimens with error calls as Streptococcus spp. by using manual analysis. CONCLUSIONS: With help of the manual review of the microarray images, the BC-GP assay could successfully identify species and resistance markers for many clinically important Gram-positive bacteria.201525536666
582920.9909Diagnosing Antibiotic Resistance Using Nucleic Acid Enzymes and Gold Nanoparticles. The rapid and accurate detection of antimicrobial resistance is critical to limiting the spread of infections and delivering effective treatments. Here, we developed a rapid, sensitive, and simple colorimetric nanodiagnostic platform to identify disease-causing pathogens and their associated antibiotic resistance genes within 2 h. The platform can detect bacteria from different biological samples (i.e., blood, wound swabs) with or without culturing. We validated the multicomponent nucleic acid enzyme-gold nanoparticle (MNAzyme-GNP) platform by screening patients with central line associated bloodstream infections and achieved a clinical sensitivity and specificity of 86% and 100%, respectively. We detected antibiotic resistance in methicillin-resistant Staphylococcus aureus (MRSA) in patient swabs with 90% clinical sensitivity and 95% clinical specificity. Finally, we identified mecA resistance genes in uncultured nasal, groin, axilla, and wound swabs from patients with 90% clinical sensitivity and 95% clinical specificity. The simplicity and versatility for detecting bacteria and antibiotic resistance markers make our platform attractive for the broad screening of microbial pathogens.202133970612
579830.9909Rapid identification of bacteria, mecA and van genes from blood cultures. The Genotype technology, a quick molecular genetic assay based on DNA multiplex amplification with biotinylated primers followed by hybridization to membrane bound probes, complies with the requirements for a fast diagnosis of sepsis. We evaluated the new Genotype BC Gram-negative and Gram-positive test kits (Hain Life Science, Germany) which respectively allow for the identification of 15 species of Gram-negative (GN) rods, and the identification of 17 Gram-positive (GP) bacteria species together with the determination of methicillin and vancomycin resistance (mecA and van genes). The study was performed on 60 positive blood cultures from BacT/ALERT bottles (aerobic, anaerobic and pediatric bottles). First, a Gram stain was carried out to select between Genotype BC GP or GN test, then identification were performed by the Genotype BC tests and by biochemical conventional tests after subculture and phenotypic susceptibility determination. The operating procedure was very easy to carry out and required a small amount of starting material (5 to 10 microL of blood culture). The results were available within 4.5 hours. For all the blood cultures, the Genotype BC results correlated with the biochemical identification and phenotypic antibiotics susceptibility. According to our results, this DNA strip technology based assay can easily be incorporated into routine diagnosis.200717913394
148640.9908Multicenter evaluation of the Verigene Gram-negative blood culture nucleic acid test for rapid detection of bacteria and resistance determinants in positive blood cultures. The Verigene Gram-Negative Blood Culture Nucleic Acid Test (BC-GN) is a microarray-based assay that enables rapid detection of 9 common Gram-negative bacteria and 6 resistance determinants directly from positive blood cultures. We compared the performance of BC-GN with currently used automated systems, testing 141 clinical blood cultures and 205 spiked blood cultures. For identification of BC-GN target organisms in clinical and spiked blood cultures, the BC-GN assay showed 98.5% (130/132) and 98.9% (182/184) concordance, respectively. Of 140 resistance genes positively detected in clinical and spiked blood cultures with the BC-GN test, 139 (99.3%) were confirmed by PCR, and the detection results were consistent with the resistance phenotypes observed. The BC-GN assay, thus, can potentially improve care for sepsis patients by enabling timely detection and targeted antimicrobial therapy.201526361710
223650.9907Development of a Multiplex PCR Platform for the Rapid Detection of Bacteria, Antibiotic Resistance, and Candida in Human Blood Samples. The diagnosis of bloodstream infections (BSIs) still relies on blood culture (BC), but low turnaround times may hinder the early initiation of an appropriate antimicrobial therapy, thus increasing the risk of infection-related death. We describe a direct and rapid multiplex PCR-based assay capable of detecting and identifying 16 bacterial and four Candida species, as well as three antibiotic-resistance determinants, in uncultured samples. Using whole-blood samples spiked with microorganisms at low densities, we found that the MicrobScan assay had a mean limit of detection of 15.1 ± 3.3 CFU of bacteria/Candida per ml of blood. When applied to positive BC samples, the assay allowed the sensitive and specific detection of BSI pathogens, including bla(KPC)-, mecA-, or vanA/vanB-positive bacteria. We evaluated the assay using prospectively collected blood samples from patients with suspected BSI. The sensitivity and specificity were 86.4 and 97.0%, respectively, among patients with positive BCs for the microorganisms targeted by the assay or patients fulfilling the criteria for infection. The mean times to positive or negative assay results were 5.3 ± 0.2 and 5.1 ± 0.1 h, respectively. Fifteen of 20 patients with MicrobScan assay-positive/BC-negative samples were receiving antimicrobial therapy. In conclusion, the MicrobScan assay is well suited to complement current diagnostic methods for BSIs.201931799215
223960.9907The Direct Semi-Quantitative Detection of 18 Pathogens and Simultaneous Screening for Nine Resistance Genes in Clinical Urine Samples by a High-Throughput Multiplex Genetic Detection System. BACKGROUND: Urinary tract infections (UTIs) are one the most common infections. The rapid and accurate identification of uropathogens, and the determination of antimicrobial susceptibility, are essential aspects of the management of UTIs. However, existing detection methods are associated with certain limitations. In this study, a new urinary tract infection high-throughput multiplex genetic detection system (UTI-HMGS) was developed for the semi-quantitative detection of 18 pathogens and the simultaneously screening of nine resistance genes directly from the clinical urine sample within 4 hours. METHODS: We designed and optimized a multiplex polymerase chain reaction (PCR) involving fluorescent dye-labeled specific primers to detect 18 pathogens and nine resistance genes. The specificity of the UTI-HMGS was tested using standard strains or plasmids for each gene target. The sensitivity of the UTI-HMGS assay was tested by the detection of serial tenfold dilutions of plasmids or simulated positive urine samples. We also collected clinical urine samples and used these to perform urine culture and antimicrobial susceptibility testing (AST). Finally, all urine samples were detected by UTI-HMGS and the results were compared with both urine culture and Sanger sequencing. RESULTS: UTI-HMGS showed high levels of sensitivity and specificity for the detection of uropathogens when compared with culture and sequencing. In addition, ten species of bacteria and three species of fungi were detected semi-quantitatively to allow accurate discrimination of significant bacteriuria and candiduria. The sensitivity of the UTI-HMGS for the all the target genes could reach 50 copies per reaction. In total, 531 urine samples were collected and analyzed by UTI-HMGS, which exhibited high levels of sensitivity and specificity for the detection of uropathogens and resistance genes when compared with Sanger sequencing. The results from UTI-HMGS showed that the detection rates of 15 pathogens were significantly higher (P<0.05) than that of the culture method. In addition, there were 41(7.72%, 41/531) urine samples were positive for difficult-to-culture pathogens, which were missed detected by routine culture method. CONCLUSIONS: UTI-HMGS proved to be an efficient method for the direct semi-quantitative detection of 18 uropathogens and the simultaneously screening of nine antibiotic resistance genes in urine samples. The UTI-HMGS could represent an alternative method for the clinical detection and monitoring of antibiotic resistance.202133912478
582770.9907Duplex dPCR System for Rapid Identification of Gram-Negative Pathogens in the Blood of Patients with Bloodstream Infection: A Culture-Independent Approach. Early and accurate detection of pathogens is important to improve clinical outcomes of bloodstream infections (BSI), especially in the case of drug-resistant pathogens. In this study, we aimed to develop a culture-independent digital PCR (dPCR) system for multiplex detection of major sepsiscausing gram-negative pathogens and antimicrobial resistance genes using plasma DNA from BSI patients. Our duplex dPCR system successfully detected nine targets (five bacteria-specific targets and four antimicrobial resistance genes) through five reactions within 3 hours. The minimum detection limit was 50 ag of bacterial DNA, suggesting that 1 CFU/ml of bacteria in the blood can be detected. To validate the clinical applicability, cell-free DNA samples from febrile patients were tested with our system and confirmed high consistency with conventional blood culture. This system can support early identification of some drug-resistant gram-negative pathogens, which can help improving treatment outcomes of BSI.202134528911
147780.9907Multicenter Evaluation of the BIOFIRE Blood Culture Identification 2 Panel for Detection of Bacteria, Yeasts, and Antimicrobial Resistance Genes in Positive Blood Culture Samples. Diagnostic tools that can rapidly identify and characterize microbes growing in blood cultures are important components of clinical microbiology practice because they help to provide timely information that can be used to optimize patient management. This publication describes the bioMérieux BIOFIRE Blood Culture Identification 2 (BCID2) Panel clinical study that was submitted to the U.S. Food & Drug Administration. Results obtained with the BIOFIRE BCID2 Panel were compared to standard-of-care (SoC) results, sequencing results, PCR results, and reference laboratory antimicrobial susceptibility testing results to evaluate the accuracy of its performance. Results for 1,093 retrospectively and prospectively collected positive blood culture samples were initially enrolled, and 1,074 samples met the study criteria and were included in the final analyses. The BIOFIRE BCID2 Panel demonstrated an overall sensitivity of 98.9% (1,712/1,731) and an overall specificity of 99.6% (33,592/33,711) for Gram-positive bacteria, Gram-negative bacteria and yeast targets which the panel is designed to detect. One hundred eighteen off-panel organisms, which the BIOFIRE BCID2 Panel is not designed to detect, were identified by SoC in 10.6% (114/1,074) of samples. The BIOFIRE BCID2 Panel also demonstrated an overall positive percent agreement (PPA) of 97.9% (325/332) and an overall negative percent agreement (NPA) of 99.9% (2,465/2,767) for antimicrobial resistance determinants which the panel is designed to detect. The presence or absence of resistance markers in Enterobacterales correlated closely with phenotypic susceptibility and resistance. We conclude that the BIOFIRE BCID2 Panel produced accurate results in this clinical trial.202337227281
223390.9906Assessment of the multiplex PCR-based assay Unyvero pneumonia application for detection of bacterial pathogens and antibiotic resistance genes in children and neonates. BACKGROUND: Pneumonia is a major healthcare problem. Rapid pathogen identification is critical, but often delayed due to the duration of culturing. Early, broad antibacterial therapy might lead to false-negative culture findings and eventually to the development of antibiotic resistances. We aimed to assess the accuracy of the new application Unyvero P50 based on multiplex PCR to detect bacterial pathogens in respiratory specimens from children and neonates. METHODS: In this prospective study, bronchoalveolar lavage fluids, tracheal aspirates, or pleural fluids from neonates and children were analyzed by both traditional culture methods and Unyvero multiplex PCR. RESULTS: We analyzed specimens from 79 patients with a median age of 1.8 (range 0.01-20.1). Overall, Unyvero yielded a sensitivity of 73.1% and a specificity of 97.9% compared to culture methods. Best results were observed for non-fermenting bacteria, for which sensitivity of Unyvero was 90% and specificity 97.3%, while rates were lower for Gram-positive bacteria (46.2 and 93.9%, respectively). For resistance genes, we observed a concordance with antibiogram of 75% for those specimens in which there was a cultural correlate. CONCLUSIONS: Unyvero is a fast and easy-to-use tool that might provide additional information for clinical decision making, especially in neonates and in the setting of nosocomial pneumonia. Sensitivity of the PCR for Gram-positive bacteria and important resistance genes must be improved before this application can be widely recommended.201829086343
2477100.9906Evaluation of targeted next-generation sequencing for microbiological diagnosis of acute lower respiratory infection. PURPOSE: To evaluate the performance of targeted next-generation sequencing (tNGS) in pathogen detection in acute lower respiratory infection. METHODS: The retrospective study was conducted between July 2023 and May 2024 at the Yantai Yuhuangding Hospital. Patients with acute lower respiratory infections were included. Qualified sputum or bronchoalveolar lavage fluid samples were collected for tNGS and conventional microbiological tests(CMTs), including culture, staining, polymerase chain reaction (PCR), and reverse transcription-PCR (RT-PCR). The time required and cost were counted. RESULTS: A total of 968 patients were enrolled. Study analysis discovered 1,019 strains of bacteria, 259 strains of fungi, 302 strains of viruses, 76 strains of Mycoplasma pneumoniae, and two strains of Chlamydia psittaci using tNGS. In addition, tNGS also identified 39 mecA, four KPC, 19 NDM, and two OXA-48 genes. The positive rates for bacteria, fungi, viruses, mycoplasma, and chlamydia obtained using tNGS were significantly higher than those determined using traditional methods. Among them, tNGS showed high consistence with mycobacterium DNA test, influenza A (H1N1) virus nucleic acid test and COVID-19 nucleic acid test. Poor consistency between drug resistance genes and bacterial resistance phenotypes was found. In addition, tNGS also had advantages over traditional methods in terms of detection time and cost. CONCLUSION: Compared to traditional methods, tNGS had higher sensitivity in detecting bacteria, fungi, viruses, and other pathogens in acute lower respiratory infection, and also had the advantages of timeliness and cost-effectiveness, making it a promising method for guiding clinical diagnosis.202540901079
5796110.9905Antibiotic treatment algorithm development based on a microarray nucleic acid assay for rapid bacterial identification and resistance determination from positive blood cultures. Rapid diagnosis of bloodstream infections remains a challenge for the early targeting of an antibiotic therapy in sepsis patients. In recent studies, the reliability of the Nanosphere Verigene Gram-positive and Gram-negative blood culture (BC-GP and BC-GN) assays for the rapid identification of bacteria and resistance genes directly from positive BCs has been demonstrated. In this work, we have developed a model to define treatment recommendations by combining Verigene test results with knowledge on local antibiotic resistance patterns of bacterial pathogens. The data of 275 positive BCs were analyzed. Two hundred sixty-three isolates (95.6%) were included in the Verigene assay panels, and 257 isolates (93.5%) were correctly identified. The agreement of the detection of resistance genes with subsequent phenotypic susceptibility testing was 100%. The hospital antibiogram was used to develop a treatment algorithm on the basis of Verigene results that may contribute to a faster patient management.201626712265
1475120.9905Evaluation of the FilmArray(®) Pneumonia Plus Panel for Rapid Diagnosis of Hospital-Acquired Pneumonia in Intensive Care Unit Patients. The FilmArray(®) Pneumonia plus Panel (FAPP) is a new multiplex molecular test for hospital-acquired pneumonia (HAP), which can rapidly detect 18 bacteria, 9 viruses, and 7 resistance genes. We aimed to compare the diagnosis performance of FAPP with conventional testing in 100 intensive care unit (ICU) patients who required mechanical ventilation, with clinically suspected HAP. A total of 237 samples [76 bronchoalveolar lavages (BAL(DS)) and 82 endotracheal aspirates (ETA(DS)) obtained at HAP diagnosis, and 79 ETA obtained during follow-up (ETA(TT))], were analyzed independently by routine microbiology testing and FAPP. 58 patients had paired BAL(DS) and ETA(DS). The positivity thresholds of semi-quantified bacteria were 10(3)-10(4) CFUs/mL or 10(4) copies/mL for BAL, and 10(5) CFUs/mL or copies/mL for ETA. Respiratory commensals (H. influenzae, S. aureus, E. coli, S. pneumoniae) were the most common pathogens. Discordant results for bacterial identification were observed in 33/76 (43.4%) BAL(DS) and 36/82 (43.9%) ETA(DS), and in most cases, FAPP identified one supplemental bacteria (23/33 BAL(DS) and 21/36 ETA(DS)). An absence of growth, or polybacterial cultures, explained almost equally the majority of the non-detections in culture. No linear relationship was observed between bin and CFUs/mL variables. Concordant results between paired BAL(DS) and ETA(DS) were obtained in 46/58 (79.3%) patients with FAPP. One of the 17 resistance genes detected with FAPP (mecA/C and MREJ) was not confirmed by conventional testing. Overall, FAPP enhanced the positivity rate of diagnostic testing, with increased recognition of coinfections. Implementing this strategy may allow clinicians to make more timely and informed decisions.202032983057
2224130.9905Multiplexed Signal Ion Emission Reactive Release Amplification (SIERRA) Assay for the Culture-Free Detection of Gram-Negative and Gram-Positive Bacteria and Antimicrobial Resistance Genes. The global prevalence of antibiotic-resistant bacteria has increased the risk of dangerous infections, requiring rapid diagnosis and treatment. The standard method for diagnosis of bacterial infections remains dependent on slow culture-based methods, carried out in central laboratories, not easily extensible to rapid identification of organisms, and thus not optimal for timely treatments at the point-of-care (POC). Here, we demonstrate rapid detection of bacteria by combining electrochemical immunoassays (EC-IA) for pathogen identification with confirmatory quantitative mass spectral immunoassays (MS-IA) based on signal ion emission reactive release amplification (SIERRA) nanoparticles with unique mass labels. This diagnostic method uses compatible reagents for all involved assays and standard fluidics for automatic sample preparation at POC. EC-IA, based on alkaline phosphatase-conjugated pathogen-specific antibodies, quantified down to 10(4) bacteria per sample when testing Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa lysates. EC-IA quantitation was also obtained for wound samples. The MS-IA using nanoparticles against S. aureus, E. coli, Klebsiella pneumoniae, and P. aeruginosa allowed selective quantitation of ∼10(5) bacteria per sample. This method preserves bacterial cells allowing extraction and amplification of 16S ribosomal RNA genes and antibiotic resistance genes, as was demonstrated through identification and quantitation of two strains of E. coli, resistant and nonresistant due to β-lactamase cefotaximase genes. Finally, the combined immunoassays were compared against culture using remnant deidentified patient urine samples. The sensitivities for these immunoassays were 83, 95, and 92% for the prediction of S. aureus, P. aeruginosa, and E. coli or K. pneumoniae positive culture, respectively, while specificities were 85, 92, and 97%. The diagnostic platform presented here with fluidics and combined immunoassays allows for pathogen isolation within 5 min and identification in as little as 15 min to 1 h, to help guide the decision for additional testing, optimally only on positive samples, such as multiplexed or resistance gene assays (6 h).202133819029
1478140.9904Multicenter Evaluation of the FilmArray Blood Culture Identification 2 Panel for Pathogen Detection in Bloodstream Infections. The FilmArray Blood Culture Identification 2 panel (BCID2; bioMérieux) is a fully automated PCR-based assay for identifying bacteria, fungi, and bacterial resistance markers in positive blood cultures (BC) in about 1 h. In this multicenter study, we evaluated the performance of the BCID2 panel for pathogen detection in positive BC. Conventional culture and BCID2 were performed in parallel at four tertiary-care hospitals. We included 152 positive BC-130 monomicrobial and 22 polymicrobial cultures-in this analysis. The BCID2 assay correctly identified 90% (88/98) of Gram-negative and 89% (70/79) of Gram-positive bacteria. Five bacterial isolates targeted by the BCID2 panel and recovered from five positive BC, including three polymicrobial cultures, were missed by the BCID2 assay. Fifteen isolates were off-panel organisms, accounting for 8% (15/182) of the isolates obtained from BC. The mean positive percent agreement between the BCID2 assay and standard culture was 97% (95% confidence interval, 95 to 99%), with agreement ranging from 67% for Candida albicans to 100% for 17 targets included in the BCID2 panel. BCID2 also identified the bla(CTX-M) gene in seven BC, including one for which no extended-spectrum β-lactamase (ESBL)-producing isolate was obtained in culture. However, it failed to detect ESBL-encoding genes in three BC. Two of the 18 mecA/C genes detected by the BCID2 were not confirmed. No carbapenemase, mecA/C, or MREJ targets were detected. The median turnaround time was significantly shorter for BCID2 than for culture. The BCID2 panel may facilitate faster pathogen identification in bloodstream infections. IMPORTANCE Rapid molecular diagnosis combining the identification of pathogens and the detection of antibiotic resistance genes from positive blood cultures (BC) can improve the outcome for patients with bloodstream infections. The FilmArray BCID2 panel, an updated version of the original BCID, can detect 11 Gram-positive bacteria, 15 Gram-negative bacteria, 7 fungal pathogens, and 10 antimicrobial resistance genes directly from a positive BC. Here, we evaluated the real-life microbiological performance of the BCID2 assay in comparison to the results of standard methods used in routine practice at four tertiary care hospitals.202336519852
5826150.9904Rapid and accurate sepsis diagnostics via a novel probe-based multiplex real-time PCR system. Sepsis is a critical clinical emergency that requires prompt diagnosis and intervention. Its prevalence has increased due to the aging population and increased antibiotic resistance. Early identification and the use of innovative technologies are crucial for improving patient outcomes. Modern methodologies are needed to minimize the turnaround time for diagnosis and improve outcomes. Rapid diagnostic tests and multiplex PCR are effective but have limitations in identifying a range of pathogens and target genes. Our study evaluated two novel probe-based multiplex real-time PCR systems: the SEPSI ID and SEPSI DR panels. These systems can quickly identify bacterial and fungal pathogens, alongside antibiotic resistance genes. The assays cover 29 microorganisms (gram-negative bacteria, gram-positive bacteria, yeast, and mold species), alongside 23 resistance genes and four virulence factors. A streamlined workflow uses 2 µL of broth from positive blood cultures (BCs) without nucleic acid extraction and provides results in approximately 1 h. We present the results from an evaluation of 228 BCs and 22 isolates previously characterized by whole-genome sequencing. In comparison to the reference methods, the SEPSI ID panel demonstrated a sensitivity of 96.88%, a specificity of 100%, and a PPV of 100%, whereas the SEPSI DR panel showed a sensitivity of 97.8%, a PPV of 89.7%, and a specificity of 96.7%. Both panels also identified additional pathogens and resistance-related targets not detected by conventional methods. This assay shows promise for rapidly and accurately diagnosing sepsis. Future studies should validate its performance in various clinical settings to enhance sepsis management and improve patient outcomes.IMPORTANCEWe present a new diagnostic method that enables the quick and precise identification of pathogens and resistance genes from positive blood cultures, eliminating the need for nucleic acid extraction. This technique can also be used on fresh pathogen cultures. It has the potential to greatly improve treatment protocols, leading to better patient outcomes, more responsible antibiotic use, and more efficient management of healthcare resources.202541025980
5828160.9903Target-enriched sequencing enables accurate identification of bloodstream infections in whole blood. Bloodstream infections are within the top ten causes of death globally, with a mortality rate of up to 70%. Gold standard blood culture testing is time-consuming, resulting in delayed, but accurate, treatment. Molecular methods, such as RT-qPCR, have limited targets in one run. We present a new Ampliseq detection system (ADS) combining target amplification and next-generation sequencing for accurate identification of bacteria, fungi, and antimicrobial resistance determinants directly from blood samples. In this study, we included removal of human genomic DNA during nucleic acid extraction, optimized the target sequence set and drug resistance genes, performed antimicrobial resistance profiling of clinical isolates, and evaluated mock specimens and clinical samples by ADS. ADS successfully identified pathogens at the species-level in 36 h, from nucleic acid extraction to results. Besides pathogen identification, ADS can also present drug resistance profiles. ADS enabled detection of all bacteria and accurate identification of 47 pathogens. In 20 spiked samples and 8 clinical specimens, ADS detected at least 92.81% of reads mapped to pathogens. ADS also showed consistency with the three culture-negative samples, and correctly identified pathogens in four of five culture-positive clinical blood specimens. This Ampliseq-based technology promises broad coverage and accurate pathogen identification, helping clinicians to accurately diagnose and treat bloodstream infections.202234915067
2238170.9903Rapid detection of carbapenem resistance among gram-negative organisms directly from positive blood culture bottles. BACKGROUND: Carbapenemase producing gram-negative bacteria (GNB) has become a huge problem in majority of tertiary care centers worldwide. They are associated with very high morbidity and mortality rates, especially when they cause invasive infections. Therefore, rapid detection of these organisms is very important for prompt and adequate antibiotic therapy as well as infection control. The aim of this study was rapid detection of carbapenemase genes and thereby likely carbapenem resistance, 24-48 hours in advance, directly from the positive-flagged blood culture bottles using CHROMagar and Xpert® Carba-R. METHODS: Aspirate from positively flagged blood culture bottles was subjected to differential centrifuge. All gram-negative bacilli on gram stain from the deposit were processed in Xpert® Carba-R and inoculated on CHROMagar. The presence of genes and growth on CHROMagar was compared with carbapenem resistance on VITEK-2 Compact. RESULTS: A total of 119 GNB isolates were processed. One or more of the carbapenemase genes were detected in 80 isolates. On comparison with VITEK-2 result, 92 samples showed concordance for carbapenem resistance 48 hours in advance. There was discordance in 21 isolates with 12 major errors and 09 minor errors. The sensitivity of direct Xpert® Carba-R test for rapid detection of carbapenem resistance, 48 hours in advance, was 81.42%. The sensitivity of direct CHROMagar test for accurate detection of carbapenem resistance, 24 hours in advance, was 92.06%. CONCLUSION: The ability to detect carbapenem resistance with very high accuracy, 48 hours in advance, helps in appropriate antibiotic therapy and implementation of effective infection control practices.202337193528
5833180.9902Rapid identification, virulence analysis and resistance profiling of Staphylococcus aureus by gene segment-based DNA microarrays: application to blood culture post-processing. Up to now, blood culturing systems are the method of choice to diagnose bacteremia. However, definitive pathogen identification from positive blood cultures is a time-consuming procedure, requiring subculture and biochemical analysis. We developed a microarray for the identification of Staphylococcus aureus comprising PCR generated gene-segments, which can reduce the blood culture post-processing time to a single day. Moreover, it allows concomitant identification of virulence factors and antibiotic resistance determinants directly from positive blood cultures without previous amplification by PCR. The assay unambiguously identifies most of the important virulence genes such as tsst-1, sea, seb, eta and antibiotic resistance genes such as mecA, aacA-aphD, blaZ and ermA. To obtain positive signals, 20 ng of purified genomic S. aureus DNA or 2 microg of total DNA extracted from blood culture was required. The microarray specifically distinguished S. aureus from gram-negative bacteria as well as from closely related coagulase negative staphylococci (CoNS). The microarray-based identification of S. aureus can be accomplished on the same day blood cultures become positive in the Bactec. The results of our study demonstrate the feasibility of microarray-based systems for the direct identification and characterization of bacteria from cultured clinical specimens.200717141897
5094190.9901A duplex one-step recombinase aided PCR assay for the rapid and sensitive detection of the isoniazid resistance genes katG and inhA in Mycobacterium tuberculosis. OBJECTIVES: Drug resistance in tuberculosis seriously affects the eradication of tuberculosis, and isoniazid resistance is the second most commonly observed drug resistance in patients with tuberculosis. Timely and accurate detection of isoniazid resistance is critical to the treatment of tuberculosis. METHODS: A duplex one-step recombinase-aided PCR (DO-RAP) assay was developed for the rapid and sensitive detection of the katG Ser315Thr and inhA-15 (C-T) mutations in Mycobacterium tuberculosis, which are the most common isoniazid-resistant mutations. Quantitative recombinant plasmids were used to evaluate the sensitivity of DO-RAP, and 91 Mycobacterium tuberculosis strains with different genotypes, as well as 5 common respiratory tract bacteria, were used to evaluate the specificity of DO-RAP. A total of 78 sputum specimens were simultaneously detected using DO-RAP, quantitative PCR (qPCR) and sanger sequencing of nested PCR products. Sanger sequencing results were used as the standard to verify the clinical performance of DO-RAP. RESULTS: The reaction time of DO-RAP was less than 1 h. The sensitivity of DO-RAP was 2 copies/reaction, which was 10 times higher than qPCR. The sensitivity of DO-RAP for detecting heterogenous resistance was 5%. There was no cross-reactivity between the isoniazid wild-type gene, drug-resistant mutant genes, and other common respiratory tract bacteria. Compared with Sanger sequencing, the sensitivity, specificity, PPV and NPV of DO-RAP were all 100%. There were 7 specimens with gray zone or negative qPCR results but positive DO-RAP test results. CONCLUSION: The DO-RAP can be adopted in ordinary qPCR equipment for the rapid, highly sensitive and specific detection of the isoniazid resistance genes of Mycobacterium tuberculosis.202540182291