[Evaluation of Seeplex RV detection kit for detecting rhinovirus, human metapneumovirus, and coronavirus]

Development and validation of a multiplex-PCR based assay for the detection of 18 pathogens in the cerebrospinal fluid of hospitalized children with viral encephalitis

BACKGROUND

The Applied Biosystems 3500 Genetic Analyzer (ABI3500) allows for automated capillary electrophoresis on multiple targets. So far, the application of this method for detecting cerebrospinal fluid pathogens has hardly been reported.

METHODS

To assess the performance of multiplex-PCR assay for 18 pathogens detection, 127 CSF samples from hospitalized children with suspected viral encephalitis were prospectively collected from April to November 2018. The Sanger sequencing was applied to verify this assay.

RESULTS

All of the 18 target pathogens can be identified by multiplex-PCR assay at 10⁴ copies (or CFU/mL) of each virus, bacterium and fungus. In contrast, 10 control microorganisms failed to be amplified. Approximately 68.5 % of the cases tested had positive results, the enterovirus accounted for the majority of the positive cases (63.8 %). Agreement between multiplex-PCR and sequencing was 91.49 %.

CONCLUSIONS

Our findings suggest that the ABI3500-based multiplex-PCR detection kit could be a valuable diagnostic tool for pathogen detection in CSF of children with suspected viral encephalitis.

Comparison of three rapid influenza diagnostic tests with digital readout systems and one conventional rapid influenza diagnostic test

Background

Rapid influenza diagnostic tests (RIDTs) show variable sensitivities in clinical settings. We aimed to compare three digital RIDTs and one conventional RIDT.

Methods

We assessed 218 nasopharyngeal swabs from patients between neonates and 90 years old in 2016. Three digital RIDTs were BUDDI, Sofia Influenza A+B Fluorescence Immunoassay, Veritor System Flu A+B assay. One conventional test was the SD Bioline Influenza Ag A/B/A(H1N1/2009). All test results were compared with those from the Anyplex Flu A/B Typing Real‐time Detection real‐time PCR. The four RIDTs were tested with diluted solutions from the National Institute for Biological Standards and Control (NIBSC) to compare lower detection limit. Cross‐reactivity of four RIDTs within other respiratory viruses was identified.

Results

For influenza A, BUDDI, Sofia, Veritor, and Bioline showed 87.7%, 94.5%, 87.7%, and 72.6% sensitivity, and 100%, 97.7%, 96.5%, and 100% specificity. For influenza B, BUDDI, Sofia, Veritor, and Bioline showed 81.7%, 91.7%, 81.7%, and 78.3% sensitivity, and 100%, 95.3%, 100%, and 100% specificity, respectively. Each RIDT could detect diluted NIBSC solution, according to the level of dilution and specific influenza subtypes. Cross‐reactivity of four RIDTs with other respiratory viruses was not noted.

Conclusions

Sofia showed the highest sensitivity for influenza A and B detection. BUDDI and Veritor showed higher detection sensitivity than a conventional RIDT for influenza A detection, but similar results for influenza B detection. Further study is needed to compare the test performance of RIDTs according to specific, prevalent influenza subtypes.

Respiratory Infections

The majority of respiratory tract infections (RTIs) are community acquired and are the single most common cause of physician office visits and among the most common causes of hospitalizations. The morbidity and mortality associated with RTIs are significant and the financial and social burden high due to lost time at work and school. The scope of clinical symptoms can significantly overlap among the respiratory pathogens, and the severity of disease can vary depending on patient age, underlying disease, and immune status, thereby leading to inaccurate presumptions about disease etiology. The rapid and accurate diagnosis of the causative agent of RTIs improves patient care, reduces morbidity and mortality, promotes effective hospital bed utilization and antibiotic stewardship, and reduces length of stay. This chapter focuses on the clinical utility, advantages, and disadvantages of viral and bacterial tests cleared by the Food and Drug Administration (FDA), and new promising technologies for the detection of bacterial agents of pneumonia currently in development or in US FDA clinical trials are briefly reviewed.

Evaluation of the Seeplex® Meningitis ACE Detection kit for the detection of 12 common bacterial and viral pathogens of acute meningitis

BACKGROUND

Bacterial meningitis is an infectious disease with high rates of mortality and high frequency of severe sequelae. Early identification of causative bacterial and viral pathogens is important for prompt and proper treatment of meningitis and for prevention of life-threatening clinical outcomes. In the present study, we evaluated the value of the Seeplex Meningitis ACE Detection kit (Seegene Inc., Korea), a newly developed multiplex PCR kit employing dual priming oligonucleotide methods, for diagnosing acute meningitis.

METHODS

Analytical sensitivity of the kit was studied using reference strains for each pathogen targeted by the kit, while it's analytical specificity was studied using the human genome DNA and 58 clinically well-identified reference strains. For clinical validation experiment, we used 27 control cerebrospinal fluid (CSF) samples and 78 clinical CSF samples collected from patients at the time of diagnosis of acute meningitis.

RESULTS

The lower detection limits ranged from 10(1) copies/µL to 5×10(1) copies/µL for the 12 viral and bacterial pathogens targeted. No cross-reaction was observed. In the validation study, high detection rate of 56.4% was obtained. None of the control samples tested positive, i.e., false-positive results were absent.

CONCLUSIONS

The Seeplex Meningitis ACE Detection kit showed high sensitivity, specificity, and detection rate for the identification of pathogens in clinical CSF samples. This kit may be useful for rapid identification of important acute meningitis-causing pathogens.

Advances in viral disease diagnostic and molecular epidemiological technologies

The early and rapid detection and characterization of specific nucleic acids of medico-veterinary pathogens have proven invaluable for diagnostic purposes. The integration of amplification and signal detection systems, including online real-time devices, have increased speed and sensitivity and greatly facilitated the quantification of target nucleic acids. They have also allowed for sequence characterization using melting or hybridization curves. The newer-generation molecular diagnostic technologies offer, hitherto, unparalleled detection and discrimination methodologies, which are vital for the positive detection and identification of pathogenic agents, as well as the effects of the pathogens on the production of antibodies. The development phase of the novel technologies entails a thorough understanding of accurate diagnosis and discrimination of present and emerging diseases. The development of novel technologies can only be successful if they are transferred and used in the field with a sustainable quality-assured application to allow for the optimal detection and effective control of diseases. The aim of these new tools is to detect the presence of a pathogen agent before the onset of disease. This manuscript focuses mainly on the experiences of two World Organisation for Animal Health collaborating centers in context to molecular diagnosis and molecular epidemiology of transboundary and endemic animal diseases of viral origin, food safety and zoonoses.

Molecular epidemiological investigation of a nosocomial outbreak of human metapneumovirus infection in a pediatric hemato-oncology patient population

We report the first nosocomial outbreak of human metapneumovirus (hMPV) infection in a pediatric patient population. Among 15 pediatric hMPV infections from March to May 2007, there was a nosocomial outbreak involving two patients sharing a room in a hemato-oncology ward with a patient with a community-acquired case of hMPV infection. The estimated incubation period was 7 to 9 days for a symptomatic nosocomial case. Sequencing of fusion genes of 15 isolates revealed two clusters belonging to subgroup A2 and one cluster belonging to subgroup B2. Three isolates from the outbreak had sequences identical to those of samples in the A2 cluster. There was also a separate nosocomial case represented by the B2 cluster.

Detection of human metapneumovirus by direct antigen test and shell vial cultures using immunofluorescent antibody staining

Human metapneumovirus (hMPV) has emerged as an important etiologic agent of upper and lower respiratory tract infections, especially in young children. Although rapid and simple diagnostic methods for hMPV are needed in clinical laboratories, routine diagnostic tests are not readily available. The purpose of this study was to evaluate a commercial anti-hMPV monoclonal antibody for a direct antigen test and a shell vial culture of hMPV. In the pilot study, 15 nasopharyngeal aspirates from 15 children with acute respiratory tract infections positive for hMPV by reverse transcriptase polymerase chain reaction (RT-PCR) were tested. Both direct antigen test and shell vial culture detected hMPV in 14 of 15 (93.3%) nasopharyngeal aspirates at initial diagnosis. In the larger group prospective study, nasopharyngeal aspirates from 92 children with acute respiratory tract infections were tested for hMPV with RT-PCR, direct antigen test, and shell vial culture. Both direct antigen test and shell vial culture showed positivity for 4 out of 5 specimens positive by RT-PCR. These findings indicate that direct antigen test and shell vial culture would be reliable and timely methods for the diagnosis of hMPV infection in clinical laboratories.