Detection Of Infectious Pathogens Research Articles

A Foldable Thermoplastic Microdevice Integrating Isothermal Amplification and Schiff-Reaction-Based Colorimetric Assay for the Detection of Infectious Pathogens

In this study, we introduce a plastic-based foldable microdevice that integrates loop-mediated isothermal amplification (LAMP) and a colorimetric assay based on the Schiff reaction to detect the genes of infectious bacteria. The device comprises two sides: a sample zone containing amplification chambers and a detection zone for the colorimetric assay. The detection zone contains poly(methyl methacrylate) structures for transferring the colorimetric reagent-soaked glass micro-fiber paper into the sample chambers. Specific genes of Staphylococcus aureus (S. aureus) and Streptococcus pneumoniae (S. pneumoniae), the most common bacterial infection causes, were amplified by LAMP assay. The S. aureus gene was detected up to 10 fg/μL and the S. pneumoniae gene up to 0.1 pg/μL. The amplified target genes were visually identified using a colorimetric assay with Schiff’s reagent, which showed clear color discrimination through a reaction with aldehyde groups derived from the DNA in the amplicons. The introduced method, integrating amplification and detection processes in a single device, is expected to be utilized in point-of-care testing analysis for the simple and rapid detection of infectious pathogens.

A novel method for simultaneous detection of hematological tumors and infectious pathogens by metagenomic next generation sequencing of plasma

BackgroundMetagenomic next-generation sequencing (mNGS) is valuable for pathogen identification; however, distinguishing between infectious diseases and conditions with potentially similar clinical manifestations, including malignant tumors, is challenging. Therefore, we developed a method for simultaneous detection of infectious pathogens and cancer in blood samples. MethodsPlasma samples (n = 244) were collected from 150 and 94 patients with infections and hematological malignancies, respectively, and analyzed by mNGS for pathogen detection, alongside human tumor chromosomal copy number variation (CNV) analysis (≥5Mbp or 10Mbp CNV region). Further, an evaluation set, comprising 87 plasma samples, was analyzed by mNGS and human CNV analysis, to validate the feasibility of the method. ResultsAmong 94 patients with hematological malignancy, sensitivity values of CNV detection for tumor diagnosis were 69.15 % and 32.98 % for CNV region 5Mbp and 10Mbp, respectively, with corresponding specificities of 92.62 % and 100 % in the infection group. Area under the ROC curve (AUC) values for 5Mbp and 10Mbp region were 0.825 and 0.665, respectively, which was a significant difference of 0.160 (95 % CI: 0.110–0.210; p < 0.001), highlighting the superiority of 5Mbp output region data. Six patients with high-risk CNV results were identified in the validation study: three with history of tumor treatment, two eventually newly-diagnosed with hematological malignancies, and one with indeterminate final diagnosis. ConclusionsConcurrent CNV analysis alongside mNGS for infection diagnosis is promising for detecting malignant tumors. We recommend adopting a CNV region of 10Mbp over 5Mbp for our model, because of the lower false-positive rate (FPR).

(Invited) Functional Nucleic Acids as Bacterial and Viral Sensors

Rapid detection of infectious pathogens is vital for preventing costless outbreaks and improving human health. Current detection methods oftentimes lack the means to detect infectious pathogens in a simple, rapid, and reliable manner at the time and point of need. Functional nucleic acids (FNAs) – specifically DNA aptamers and DNAzymes – have the potential to overcome these limitations by acting as key components for point-of-care (POC) biosensors due to their distinctive advantages that include high binding affinities and specificities, excellent chemical stability, ease of synthesis and modification, and compatibility with a variety of signal-amplification and signal-transduction mechanisms. In this presentation, I will discuss the work completed in my laboratory, in collaboration with several other groups at McMaster, towards developing simple-to-use analytical devices with integrated FNAs to detect bacterial and viral pathogens, such as E. coli, Salmonella, SARS-CoV-2, porcine epidemic diarrhea virus (PEDV), directly in water, food or clinical samples.

(Invited) Real Time Monitoring of Target Binding for the Development of Clinical Diagnostic Tests

Currently, there is tremendous interest in developing continuous monitoring systems for better managing health and disease. These platforms rely on readout methods that continuously monitor the presence of bioanalytes in physiological matrices. In this talk, I will discuss the development of new electrochemical signal readout methods that continuously monitor the binding of targets with biological recognition elements such as functional nucleic acids. We will discuss the application of these platforms to the detection of infectious pathogens as a model system, but will show the possibility of its extension to protein targets.

A Point-of-Care Testing Device Utilizing Graphene-Enhanced Fiber Optic SPR Sensor for Real-Time Detection of Infectious Pathogens.

Timely detection of highly infectious pathogens is essential for preventing and controlling public health risks. However, most traditional testing instruments require multiple tedious steps and ultimately testing in hospitals and third-party laboratories. The sample transfer process significantly prolongs the time to obtain test results. To tackle this aspect, a portable fiber optic surface plasmon resonance (FO-SPR) device was developed for the real-time detection of infectious pathogens. The portable device innovatively integrated a compact FO-SPR sensing component, a signal acquisition and processing system, and an embedded power supply unit. A gold-plated fiber is used as the FO-SPR sensing probe. Compared with traditional SPR sensing systems, the device is smaller size, lighter weight, and higher convenience. To enhance the detection capacity of pathogens, a monolayer graphene was coated on the sensing region of the FO-SPR sensing probe. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was used to evaluate the performance of the portable device. The device can accurately detect the SARS-CoV-2 spike S1 protein in phosphate-buffered saline (PBS) and artificial saliva within just 20 min, and the device successfully detected cultured SARS-CoV-2 virus. Furthermore, the FO-SPR probe has long-term stability, remaining stable for up to 8 days. It could distinguish between the SARS-CoV-2 spike protein and the MERS-CoV spike protein. Hence, this FO-SPR device provides reliable, rapid, and portable access to test results. It provides a promising point-of-care testing (POCT) tool for on-site screening of infectious pathogens.

Simple and Multiplexed Detection of Nucleic Acid Targets Based on Fluorescent Ring Patterns and Deep Learning Analysis.

Simple diagnostic tests for nucleic acid targets can provide great advantages for applications such as rapid pathogen detection. Here, we developed a membrane assay for multiplexed detection of nucleic acid targets based on the visualization of two-dimensional fluorescent ring patterns. A droplet of the assay solution is applied to a cellulose nitrate membrane, and upon radial chromatographic flow and evaporation of the solvent, fluorescent patterns appear under UV irradiation. The target nucleic acid is isothermally amplified and is immediately hybridized with fluorescent oligonucleotide probes in a one-pot reaction. We established the fluorescent ring assay integrated with isothermal amplification (iFluor-RFA = isothermal fluorescent ring-based radial flow assay), and feasibility was tested using nucleic acid targets of the receptor binding domain (RBD) and RNA-dependent RNA polymerase (RdRp) genes of SARS-CoV-2. We demonstrate that the iFluor-RFA method is capable of specific and sensitive detection in the subpicomole range, as well as multiplexed detection even in complex solutions. Furthermore, we applied deep learning analysis of the fluorescence images, showing that patterns could be classified as positive or negative and that quantitative amounts of the target could be predicted. The current technique, which is a membrane pattern-based nucleic acid assay combined with deep learning analysis, provides a novel approach in diagnostic platform development that can be versatilely applied for the rapid detection of infectious pathogens.

A “turn-on” photoelectrochemical DNA biosensor based on charge transfer between BiVO4 and gold nanoparticles

An enhanced charge transfer between BiVO4 and Au nanoparticles (AuNPs) was utilized to design a “turn-on” photoelectrochemical (PEC) biosensor for sensitive detection of target DNA. The calcination of BiVO4 on indium tin oxide (ITO) substrate was integrated with Au nanoparticles (NPs) labelled probe DNA (pDNA-AuNPs) as photoelectrode (ITO/BiVO4/pDNA-AuNPs). The cathodic photocurrent increased due to the coupling BiVO4 with AuNPs, which acted as the blank signal of this PEC platform. The probe specifically recognized and captured the target DNA (tDNA) to form double strain DNA (dsDNA) after hybridization. The photocurrent intensity of the ITO/BiVO4/dsDNA-AuNPs photoelectrode further increased due to the enhancement of the charge transfer between BiVO4 and AuNPs through dsDNA chain. This photocurrent enhancement was linear proportional to the logarithm of tDNA concentration. Based on this strategy, the PEC assay displayed a linear range from 1 aM to 10 pM and the detection limit was as low as 0.2 aM (S/N = 3). It provides a promising platform for ultrasensitive target DNA detection, and thus shows a great potential in genetic disease or cancer diagnostics and infectious pathogen detection.

Single-molecule RNA capture-assisted droplet digital loop-mediated isothermal amplification for ultrasensitive and rapid detection of infectious pathogens

To minimize and control the transmission of infectious diseases, a sensitive, accurate, rapid, and robust assay strategy for application on-site screening is critical. Here, we report single-molecule RNA capture-assisted digital RT-LAMP (SCADL) for point-of-care testing of infectious diseases. Target RNA was captured and enriched by specific capture probes and oligonucleotide probes conjugated to magnetic beads, replacing laborious RNA extraction. Droplet generation, amplification, and the recording of results are all integrated on a microfluidic chip. In assaying commercial standard samples, quantitative results precisely corresponded to the actual concentration of samples. This method provides a limit of detection of 10 copies mL−1 for the N gene within 1 h, greatly reducing the need for skilled personnel and precision instruments. The ultrasensitivity, specificity, portability, rapidity and user-friendliness make SCADL a competitive candidate for the on-site screening of infectious diseases.

Highly efficient photonic PCR system based on plasmonic heating of gold nanofilms

The polymerase chain reaction (PCR) is a standard molecular method that has the potential to solve the need for accurate, viable, and immediate infectious pathogen detection at point-of-care (POC) centers in different fields such as pathogen identification, and forensics. In this work, we present a photonic PCR thermocycler that achieves strong optical absorption, more efficient gene amplification, and further improves the effect of temperature distribution through the PCR sample using two gold nanofilms (AuNFs) and a high-power light-emitting diode chip (LED). The photonic device achieved higher heating and cooling rates of 13.20 null°C/s and 7.92 null°C/s, respectively on average, with uniform and reliable temperature distribution throughout the sample with negligible deviations. During amplification cycles, maximum temperatures attained had variations less than 1 °C at 90 °C, less than 0.8 °C at 55 °C, and less than 0.5 °C at 72 °C, showing uniform heating which yielded more accurate and reliable results. Using the fabricated device, PCR amplification for a bacteria genomic DNA was performed in 7.5 minutes for 30 thermal cycles with a sample volume of 20 μL. Due to the device's simple configuration and increased heat transfer rates, this photonic platform will be a highly efficient choice for rapid POC applications in developing countries.

RNA-based isothermal amplification technology and its clinical application in pathogen infection

Abstract It is very important to detect pathogenic bacteria, viruses, or fungi in a patient’s secretion or body fluid samples as soon as possible to determine the patient’s recovery. For certain pathogens, the amount of ribosomal RNA copies contained is often tens of thousands of times higher than the amount of DNA copies, so the detection of RNA has higher sensitivity. In addition, whether for DNA pathogens or RNA pathogens, the direct detection of ribonucleic acid transcribed by pathogens in vivo can distinguish active infection or past infection, can eliminate the influence of residual DNA of pathogens that have died in the lesions, and can also avoid excessive medical interventions for transient infections, which is of great significance in the field of infectious pathogen detection. Isothermal amplification technology played important roles in molecular diagnosis because of its significant advantages. Highly sensitive RNA detection can be achieved by both direct transcription amplification and indirect amplification based on reverse transcription. Direct transcription amplification technologies relies on reverse transcriptase and T7 RNA polymerase to achieve linear transcription amplification of RNA on one-step; while the indirect amplification technology depends on a reverse transcriptional process at the beginning of the reaction. Both methods have outstanding advantages in clinical application, and commercial kits and commercial all-in-one machines based on these principles have been put into clinical use. This review mainly introduces the clinical application of isothermal amplification technologies in the detection of RNA pathogens and the main difficulties faced at this stage. It is hoped to provide insightful ideas for the construction of pathogen RNA detection technology to meet the needs of point-of-care testing in the future.

321. Clinical Utility of Metagenomic Next-Generation Sequencing in Fever of Unclear Etiology: a Single Center Retrospective Cohort Study

Abstract Background Metagenomic next-generation sequencing (mNGS) has emerged as a novel diagnostic tool in infectious diseases. It analyzes genetic material from a given sample without the need for pre-determined sequences, matching it to reference genomes, thus identifying a wide range of pathogens. There is little guidance on the efficient and appropriate use of this tool. The goal of this study was to evaluate clinical utility of mNGS in patients with fever of unclear etiology. Methods We retrospectively analyzed 72 patients at our center from June 2017 to July 2021 with “fever of unclear etiology” and a mNGS test. The assay we used was the Karius Test™, a College of American Pathologists-accredited NGS laboratory. Two independent reviews of each case were performed to determine clinical impact of mNGS using previously published criteria by Hogan et al. Logistic regression was used to identify factors associated with positive clinical impact. Results We included 72 patients, 62.5% males, median age 56. Most common comorbidities were hypertension (43.1%) and diabetes (23.6%). All patients had fever at time of evaluation. 26.4% had cough, 16.7% abdominal pain, and 15.3% shortness of breath. Median turnaround time of the test was 26 hours. At least one organism was reported in 65.3% of cases. Most common identified organisms were EBV (13.9%), CMV (12.5%), and Rickettsia typhi (11.1%). Of those with an infectious etiology of their fever, 86.8% had positive mNGS compared to 43.8% of those with non-infectious etiology (p=0.002). mNGS had positive clinical impact in 40.3% of cases, negative impact in 2.8%, and no impact in 56.9%. Based on logistic regression, older age was the only factor associated with higher odds of positive impact. Chief complaint, positivity of cultures, number of pathogens retrieved, and type of prior antibiotic use were not associated with a higher rate of positive impact. Table 1:DemographicsTable 2:mNGS Test Findings and ImpactAbbreviations: Epstein–Barr Virus (EBV); Cytomegalovirus (CMV); Escherichia coli (E. coli); Herpes Simplex Virus-1 (HSV-1)Figure 1:Organisms Identified on mNGS TestAbbreviations: Staphylococcus epidermis (S. epidermis); Klebsiella pneumoniae (K. pneumoniae); Escherichia coli (E. coli); Epstein–Barr Virus (EBV); Cytomegalovirus (CMV); Herpes Simplex Virus-1 (HSV-1); Candida albicans (C. albicans); Enterococcus faecalis (E. faecalis); Mycobacterium tuberculosis (MTB) Conclusion Overall, mNGS was clinically beneficial in a large percentage of patients, with minimal negative impact. Besides age, we did not identify other factors associated with higher likelihood of positive impact. Larger analyses and further studies on the clinical impact of mNGS in different infectious syndromes are needed to better understand this promising tool in the rapid detection of infectious pathogens. Table 3:Logistic Regression of Positive Clinical Impact of mNGS Fungitell® is an FDA-cleared assay that detects 1,3-β-D-glucan in serum Figure 2:Clinical Impact of mNGS Clinical impact based on previously published criteria by Hogan et al. Disclosures All Authors: No reported disclosures.

LAMP-Based Point-of-Care Biosensors for Rapid Pathogen Detection

Seeking optimized infectious pathogen detection tools is of primary importance to lessen the spread of infections, allowing prompt medical attention for the infected. Among nucleic-acid-based sensing techniques, loop-mediated isothermal amplification is a promising method, as it provides rapid, sensitive, and specific detection of microbial and viral pathogens and has enormous potential to transform current point-of-care molecular diagnostics. In this review, the advances in LAMP-based point-of-care diagnostics assays developed during the past few years for rapid and sensitive detection of infectious pathogens are outlined. The numerous detection methods of LAMP-based biosensors are discussed in an end-point and real-time manner with ideal examples. We also summarize the trends in LAMP-on-a-chip modalities, such as classical microfluidic, paper-based, and digital LAMP, with their merits and limitations. Finally, we provide our opinion on the future improvement of on-chip LAMP methods. This review serves as an overview of recent breakthroughs in the LAMP approach and their potential for use in the diagnosis of existing and emerging diseases.

Aptasensors for the detection of infectious pathogens: design strategies and point-of-care testing.

The epidemic of infectious diseases caused by contagious pathogens is a life-threatening hazard to the entire human population worldwide. A timely and accurate diagnosis is the critical link in the fight against infectious diseases. Aptamer-based biosensors, the so-called aptasensors, employ nucleic acid aptamers as bio-receptors for the recognition of target pathogens of interest. This review focuses on the design strategies as well as state-of-the-art technologies of aptasensor-based diagnostics for infectious pathogens (mainly bacteria and viruses), covering the utilization of three major signal transducers, the employment of aptamers as recognition moieties, the construction of versatile biosensing platforms (mostly micro and nanomaterial-based), innovated reporting mechanisms, and signal enhancement approaches. Advanced point-of-care testing (POCT) for infectious disease diagnostics are also discussed highlighting some representative ready-to-use devices to address the urgent needs of currently prevalent coronavirus disease 2019 (COVID-19). Pressing issues in aptamer-based technology and some future perspectives of aptasensors are provided for the implementation of aptasensor-based diagnostics into practical application.

Advancing pathogen detection for airborne diseases

Airborne diseases including SARS, bird flu, and the ongoing Coronavirus Disease 2019 (COVID-19) have stimulated the demand for developing novel bioassay methods competent for early-stage diagnosis and large-scale screening. Here, we briefly summarize the state-of-the-art methods for the detection of infectious pathogens and discuss key challenges. We highlight the trend for next-generation technologies benefiting from multidisciplinary advances in microfabrication, nanotechnology and synthetic biology, which allow sensitive, rapid yet inexpensive pathogen assays with portable intelligent device.

Rapid molecular testing for antimicrobial stewardship and solid organ transplantation.

Several molecular platforms now exist for early detection of infectious pathogens. In this review, we present the currently available literature summarizing clinical outcomes using rapid diagnostic tests (RDTs) in the solid organ transplant (SOT) population. We also present potential benefits and drawbacks of these technologies for SOT patients. We completed a PubMed search querying for 31 specific RDTs AND ("SOT"). We also queried PubMed for studies on RDT outcomes in the general population. References of the resulting relevant studies were reviewed and incorporated if the study population included at least one SOT patient. All culture specimen types were included. Only full-text peer-reviewed publications in English were examined. Our search yielded eleven studies. Across these studies, integrating RDTs with ASP intervention led to faster species identification and susceptibility results, faster time-to-optimal therapy, decreased hospital length-of-stay and costs, and decreased mortality. Potential drawbacks of RDTs in the SOT population included: overdiagnosis due to increased sensitivity (i.e., Clostridium difficile), decreased yield of tests for respiratory pathogens, and lack of identification of important pathogens in this population such as, Aspergillus species. Although there is a scarcity of studies involving SOT patients, current available data suggests that the use of RDTs helps improve patient outcomes and minimizes inappropriate antimicrobial use when coupled with proactive ASPs. Future studies should focus on clinical outcomes in SOT patients specifically, as well as how to optimize the use of RDTs in conjunction with traditional microbiology methods.

A Rotatable Paper Device Integrating Reverse Transcription Loop-Mediated Isothermal Amplification and a Food Dye for Colorimetric Detection of Infectious Pathogens.

In this study, we developed a rotatable paper device integrating loop-mediated isothermal amplification (RT-LAMP) and a novel naked-eye readout of the RT-LAMP results using a food additive, carmoisine, for infectious pathogen detection. Hydroxyl radicals created from the reaction between CuSO4 and H2O2 were used to decolor carmoisine, which is originally red. The decolorization of carmoisine can be interrupted in the presence of DNA amplicons produced by the RT-LAMP reaction due to how DNA competitively reacts with the hydroxyl radicals to maintain the red color of the solution. In the absence of the target DNA, carmoisine is decolored, owing to its reaction with hydroxyl radicals; thus, positive and negative samples can be easily differentiated based on the color change of the solution. A rotatable paper device was fabricated to integrate the RT-LAMP reaction with carmoisine-based colorimetric detection. The rotatable paper device was successfully used to detect SARS-CoV-2 and SARS-CoV within 70 min using the naked eye. Enterococcus faecium spiked in milk was detected using the rotatable paper device. The detection limits for the SARS-CoV-2 and SARS-CoV targets were both 103 copies/µL. The rotatable paper device provides a portable and low-cost tool for detecting infectious pathogens in a resource-limited environment.

Metagenomic Next-Generation Sequencing Versus Traditional Laboratory Methods for the Diagnosis and Treatment of Infection in Liver Transplantation

BackgroundMetagenomic next-generation sequencing (mNGS) has emerged as an effective method for the noninvasive and precise detection of infectious pathogens. However, data are lacking on whether mNGS analyses could be used for the diagnosis and treatment of infection during the perioperative period in patients undergoing liver transplantation (LT).MethodsFrom February 2018 to October 2018, we conducted an exploratory study using mNGS and traditional laboratory methods (TMs), including culture, serologic assays, and nucleic acid testing, for pathogen detection in 42 pairs of cadaveric liver donors and their corresponding recipients. Method performance in determining the presence of perioperative infection and guiding subsequent clinical decisions was compared between mNGS and TMs.ResultsThe percentage of liver donors with mNGS-positive pathogen results (64.3%, 27/42) was significantly higher than that using TMs (28.6%, 12/42; P<0.05). The percentage of co-infection detected by mNGS in liver donors was 23.8% (10/42) significantly higher than 0.0% (0/42) by TMs (P<0.01). Forty-three pathogens were detected using mNGS, while only 12 pathogens were identified using TMs. The results of the mNGS analyses were consistent with results of the TM analyses in 91.7% (11/12) of donor samples at the species level, while mNGS could be used to detect pathogens in 66.7% (20/30) of donors deemed pathogen-negative using TMs. Identical pathogens were detected in 6 cases of donors and recipients by mNGS, among which 4 cases were finally confirmed as donor-derived infections (DDIs). For TMs, identical pathogens were detected in only 2 cases. Furthermore, 8 recipients developed early symptoms of infection (<7 days) after LT; we adjusted the type of antibiotics and/or discontinued immunosuppressants according to the mNGS results. Of the 8 patients with infections, 7 recipients recovered, and 1 patient died of severe sepsis.ConclusionsOur preliminary results show that mNGS analyses can provide rapid and precise pathogen detection compared with TMs in a variety of clinical samples from patients undergoing LT. Combined with symptoms of clinical infection, mNGS showed superior advantages over TMs for the early identification and assistance in clinical decision-making for DDIs. mNGS results were critical for the management of perioperative infection in patients undergoing LT.

Persistent Pulmonary Interstitial Emphysema With Respiratory Infection: A Clinicopathological Analysis of Six Cases and Detection of Infectious Pathogens by Metagenomic Next-Generation Sequencing (mNGS).

BackgroundPersistent pulmonary interstitial emphysema (PPIE) is known to be related to mechanical ventilation and preterm. However, PPIE is also reported rarely in non-ventilated and full-term infants. Its relationship with respiratory infection is rarely reported in the literature. PPIE is difficult to diagnose and always mimics other congenital thoracic malformations (CTMs), such as congenital cystic adenomatoid malformation (CCAM).ObjectiveThe objective of this study was to evaluate clinicopathological and radiographic features of PPIE with respiratory infection and to detect the possible infectious pathogens.MethodsFrom January 2011 to December 2019, six cases were confirmed pathologically with PPIE from a large cohort of 477 resected CTMs in West China Hospital of Sichuan University. Clinical and radiographic features were obtained from patients' medical records and follow-up. The present study aimed to analyze clinicopathological and radiographic features and to detect the infectious pathogens by metagenomic next-generation sequencing (mNGS).ResultsThe six PPIE cases included four girls and two boys, ranging from 2 months to 5 years; 100% (5/5) of the available cases were full-term and without mechanical ventilation. CCAM were suspected in 66.7% (4/6) patients; 66.7% (4/6) cases affected a single lobe, and 33.3% (2/6) cases affected both lung lobes. Clinically, all six PPIEs were presented with symptoms of respiratory infection and diagnosed with pneumonia. All six patients were treated by surgery after anti-infective treatment. The pathologic characteristics showed lung cysts with variable size along the bronchovascular bundles, the cysts had a discontinuous fibrotic wall with a smooth inner surface lined with uninucleated and/or multinucleated macrophages. Streptococcus pneumoniae was detected in patient No. 1. Human beta-herpesvirus 5 was detected in patient No. 2. Neisseria mucosa, Neisseria sicca, Prevotella melaninogenica, Prevotella histicola, and Fusobacterium nucleatum were detected in patient No. 5, and no infectious pathogen was detected in 50% (3/6, No. 3, No. 4, and No. 6) of cases.ConclusionSix rare cases of PPIE with respiratory infection were treated by surgery after anti-infective treatment. All five available cases were full-term infants without mechanical ventilation. The histological characteristics of PPIE were the wall of cysts composed of a thin layer of discontinuous fibrous tissue and lined with uninucleated or/and multinucleated macrophages.

Advances in Nucleic Acid Amplification-Based Microfluidic Devices for Clinical Microbial Detection

Accurate and timely detection of infectious pathogens is urgently needed for disease treatment and control of possible outbreaks worldwide. Conventional methods for pathogen detection are usually time-consuming and labor-intensive. Novel strategies for the identification of pathogenic nucleic acids are necessary for practical application. The advent of microfluidic technology and microfluidic devices has offered advanced and miniaturized tools to rapidly screen microorganisms, improving many drawbacks of conventional nucleic acid amplification-based methods. In this review, we summarize advances in the microfluidic approach to detect pathogens based on nucleic acid amplification. We survey microfluidic platforms performing two major types of nucleic acid amplification strategies, namely, polymerase chain reaction (PCR) and isothermal nucleic acid amplification. We also provide an overview of nucleic acid amplification-based platforms including studies and commercialized products for SARS-CoV-2 detection. Technologically, we focus on the design of the microfluidic devices, the selected methods for sample preparation, nucleic acid amplification techniques, and endpoint analysis. We also compare features such as analysis time, sensitivity, and specificity of different platforms. The first section of the review discusses methods used in microfluidic devices for upstream clinical sample preparation. The second section covers the design, operation, and applications of PCR-based microfluidic devices. The third section reviews two common types of isothermal nucleic acid amplification methods (loop-mediated isothermal amplification and recombinase polymerase amplification) performed in microfluidic systems. The fourth section introduces microfluidic applications for nucleic acid amplification-based detection of SARS-CoV-2. Finally, the review concludes with the importance of full integration and quantitative analysis for clinical microbial identification.

Rapid identification of the resistance of urinary tract pathogenic bacteria using deep learning-based spectroscopic analysis.

The resistance of urinary tract pathogenic bacteria to various antibiotics is increasing, which requires the rapid detection of infectious pathogens for accurate and timely antibiotic treatment. Here, we propose a rapid diagnosis strategy for the antibiotic resistance of bacteria in urinary tract infections (UTIs) based on surface-enhanced Raman scattering (SERS) using a positively charged gold nanoparticle planar solid SERS substrate. Then, an intelligent identification model for SERS spectra based on the deep learning technique is constructed to realize the rapid, ultrasensitive, and non-labeled detection of pathogenic bacteria. A total of 54,000 SERS spectra were collected from 18 isolates belonging to 6 species of common UTI bacteria in this work to realize identification of bacterial species, antibiotic sensitivity, and multidrug resistance (MDR) via convolutional neural networks (CNN). This method significantly simplify the Raman data processing processes without background removing and smoothing, however, achieving 96% above classification accuracy, which was significantly greater than the 85% accuracy of the traditional multivariate statistical analysis algorithm principal component analysis combined with the K-nearest neighbor (PCA-KNN). This work clearly elucidated the potential of combining SERS and deep learning technique to realize culture-free identification of pathogenic bacteria and their associated antibiotic sensitivity.