Congenital Infection of Severe Acute Respiratory Syndrome Coronavirus 2 With Intrauterine Fetal Death: A Clinicopathological Study With Molecular Analysis.

BACKGROUND: Observations of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection from mother to fetus have recently been described in the literature. However, the consequences of such transmission, whether fetal or neonatal, are poorly understood. METHODS: From a case of in utero fetal death at 24+2 weeks of gestation that occurred 7 days after the diagnosis of symptomatic SARS-CoV-2 infection in the mother, we isolated the incriminating virus by immunochemistry and molecular techniques in several fetal tissues, with a variant analysis of the SARS-CoV-2 genome. RESULTS: The fetal demise could be explained by the presence of placental histological lesions, such as histiocytic intervillositis and trophoblastic necrosis, in addition to fetal tissue damage. We observed mild fetal growth retardation and visceral damage to the liver, causing hepatocellular damage and hemosiderosis. To the best of our knowledge, this is the first report in the literature of fetal demise secondary to maternal-fetal transmission of SARSCoV- 2 with a congenital infection and a pathological description of placental and fetal tissue damage. CONCLUSIONS: SARS-CoV-2 was identified in both specimens using 3 independent techniques (immunochemistry, real-time quantitative polymerase chain reaction, and realtime digital polymerase chain reaction). Furthermore, the incriminating variant has been identified.

Molecular detection of human rhinoviruses in respiratory samples: a comparison of Taqman probe-, SYBR green I- and BOXTO-based real-time PCR assays.

BACKGROUND: Human Rhinoviruses (HRV) are major causative agents of acute respiratory tract infections in all age group and important contributing factors of childhood morbidity and mortality. Clinical presentation is poorly specific and the great antigenic and genetic variability of HRVs renders the biological diagnosis complex. Here, we have evaluated several molecular diagnostic protocols, including Taqman probe-based and intercalating agent-based RT-PCR assays. METHODS: 5,627 respiratory samples sent to the laboratory of Virology of the University Hospitals of Marseille, France, from March 2011 to February 2012, were tested using a real-time RT-PCR assay in the 5'NCR of the rhinoviral genome that associated a Taqman probe and the detection of DNA-BOXTO-dye complexes. A sample of 500 BOXTO-positive samples were further tested using the same probe assay (without BOXTO), and a SYBR Green assay (using the same amplification primers). The specific amplification of HRV sequences was assessed by NGS amplicon sequencing. RESULTS: The Taqman probe RT-PCR assay identified 696/5,627 samples (12,4%) as HRV-positive. BOXTO-positive samples included all probe-positive samples and 1,913 additional samples, of which only 24.3% were confirmed by sequencing. The SYBR Green assay was more specific (16/550 samples were probe-negative/SYBR Green-positive, all confirmed by 5'NCR sequencing), but 3/500 samples were probe-positive/SYBR Green-negative. CONCLUSIONS: Our results highlight the difficulty in detecting HRVs in clinical samples using a single molecular detection system. Amongst the 3 systems tested, the best compromise was obtained with the SYBR Green assay, which, by comparison with our probe-based assay provided an improved sensitivity without altering the detection specificity. Interestingly, a majority of probe-negative/BOXTO- or SYBR Green-positive samples were not associated with mutations in the sequence targeted by the probe. Sequence-based modifications of the secondary structure of the HRV 5'NCR may be associated with a limited access to the probe hybridisation region. Further investigations may identify a test combining a probe based- and an intercalating agent-based detection, which will significantly improve the diagnosis of HRV infections.

Broad-spectrum dengue virus detection using the commercial RealStar dengue RT-PCR kit 3.0 (Altona) and an in-house combined real-time RT-PCR assay.

In endemic areas, the genetic diversity among co-circulating dengue virus (DENV) strains is considerable and new, highly divergent strains are identified on a regular basis. It is thus critical to ensure that molecular diagnostic tools effectively detect virus genomes even in case of important genetic variation. Here, we tested both the pan-DENV detection capacity and the limit of detection of two real-time RT-PCR assays: (i) the commercial RealStar Altona 3.0 system and (ii) a laboratory developed test (LDT) combining two RT-PCR systems in a single reaction tube (DenAllDUO). We used a panel of DENV strains representative of the genetic diversity within DENV species, combined with three in vitro transcribed RNAs as surrogates for unavailable strains corresponding to recently discovered strains with substantial genetic divergence: DENV serotype 1 (DENV-1) Brun2014, DENV-2 QML22 and DENV-4 DKE121. Both systems (i) targeted the genome 3' untranslated region, (ii) displayed a broad detection spectrum, encompassing most of DENV species diversity, and (iii) detected the three aforementioned divergent strains. DenAllDUO detected all the strains tested, whereas the RealStar system failed to detect strains from DENV-4 genotype III. Altogether, our findings support the value of these two RT-PCR systems as part of the Dengue diagnostic arsenal.

Evaluation of the Ridaquick Rotavirus/Adenovirus Immuno-Chromatographic Assay in Real-Life Situation.

Immunochromatographic tests (ICT) are diagnostics tools providing rapid results without the need for specialized equipment. Our aim was to evaluate retrospectively the rotavirus and adenovirus ICT routinely used in the virology laboratory serving the University Hospital of Marseille, France. From January 2017 to March 2020, 715 stool specimens from patients were screened using the Ridaquick Rotavirus/Adenovirus Combi ICT (RR/AC ICT) and a commercially available multiplex PCR detection kit. Rotavirus was detected in 9.2% of specimens by PCR and 7.7% of specimens by RR/AC ICT while adenovirus was detected in 8.5% of specimens by PCR and 2.4% of specimens by RR/AC ICT. The RR/AC ICT parameters for rotavirus were 75.8% sensitivity, 99.2% specificity, 90.9% positive predictive value (PPV) and 97.6% negative predictive value (NPV). The RR/AC ICT parameters for adenovirus were 6.6% sensitivity, 98.0% specificity, 23.5% PPV and 91.8% NPV. While the ICT test may be suitable for rotavirus detection, a PCR-based assay is better adapted for adenovirus detection in stools.

Cytomegalovirus Viral Load in Transplanted Patients Using the NeuMoDx™ (Qiagen) Automated System: A 1-Month Experience Feedback.

Cytomegalovirus (CMV) reactivations represent a significant morbidity and mortality problem in transplant patients. Reliable and rapid measurement of CMV viral load is a key issue for optimal patient management. We report here the evaluation of NeuMoDx™ (Qiagen) in a routine hospital setting (University Hospitals of Marseille, France) in comparison with our classical reference technique R-GENE. During one month, 719 CMV viral loads from 507 patients were measured in parallel in both techniques. Using the ROC (receiver operating characteristic) curve and our biological experience we suggest that values <52 IU/mL (geometric mean) correspond to negative samples, values >140 IU/mL (Fowlkes-Mallows index) correspond to quantifiable positive results and values ranging from 52 to 140 IU/mL represent non-quantifiable positive results. Follow-up of 15 transplant patients who developed CMV reactivation during the study showed that NeuMoDx™ provided higher viral load measurement during the first two weeks of follow-up for three patients. These important intra-individual variations resulted in a significant median increase considering the whole data set (6.7 points of difference expressed as a percentage of the initial viral load). However, no difference between the two techniques was noticeable after two weeks of treatment. Subsequent to this first study we conclude that NeuMoDx™, used with optimized logistics and an adapted threshold, allows a rapid CMV viral load measurement and that its use does not lead to any difference in patient management compared to the reference technique R-GENE®.

Analysis of SARS-CoV-2 Variants From 24,181 Patients Exemplifies the Role of Globalization and Zoonosis in Pandemics.

After the end of the first epidemic episode of SARS-CoV-2 infections, as cases began to rise again during the summer of 2020, we at IHU Méditerranée Infection in Marseille, France, intensified the genomic surveillance of SARS-CoV-2, and described the first viral variants. In this study, we compared the incidence curves of SARS-CoV-2-associated deaths in different countries and reported the classification of SARS-CoV-2 variants detected in our institute, as well as the kinetics and sources of the infections. We used mortality collected from a COVID-19 data repository for 221 countries. Viral variants were defined based on ≥5 hallmark mutations along the whole genome shared by ≥30 genomes. SARS-CoV-2 genotype was determined for 24,181 patients using next-generation genome and gene sequencing (in 47 and 11% of cases, respectively) or variant-specific qPCR (in 42% of cases). Sixteen variants were identified by analyzing viral genomes from 9,788 SARS-CoV-2-diagnosed patients. Our data show that since the first SARS-CoV-2 epidemic episode in Marseille, importation through travel from abroad was documented for seven of the new variants. In addition, for the B.1.160 variant of Pangolin classification (a.k.a. Marseille-4), we suspect transmission from farm minks. In conclusion, we observed that the successive epidemic peaks of SARS-CoV-2 infections are not linked to rebounds of viral genotypes that are already present but to newly introduced variants. We thus suggest that border control is the best mean of combating this type of introduction, and that intensive control of mink farms is also necessary to prevent the emergence of new variants generated in this animal reservoir.

Contribution of VitaPCR SARS-CoV-2 to the emergency diagnosis of COVID-19.

BACKGROUND: With the persistent COVID-19 pandemic, there is an urgent need to use rapid and reliable diagnostic tools for highly urgent cases. Antigen tests are disappointing with their lack of sensitivity. Among molecular tools allowing a diagnosis in less than an hour, only one, the Cepheid Xpert Xpress SARS-CoV-2 assay, has exhibited a good sensitivity. However, we are also facing a global shortage of reagents and kits. Thus, it is imperative to evaluate other point-of-care molecular tests. METHODS: We evaluated the VitaPCR™ RT-PCR assay, whose sample analysis time is of approximately 20 min, in nasopharyngeal secretions from 534 patients presenting to our Institute, for the diagnosis of COVID-19, and compared it to our routine RT-PCR assay. We also compared the two assays with tenfold dilutions of a SARS-CoV-2 strain. RESULTS: Compared to our routine RT-PCR and the previous diagnosis of COVID-19, the sensitivity, specificity, positive and negative predictive values of VitaPCR™ can be evaluated to be 99.3 % (155/156), 94.7 % (358/378), 88.6 % (155/175) and 99.7 % (358/359), respectively. Tenfold dilutions of a SARS-CoV-2 strain show that the VitaPCR™ was more sensitive that our routine RT-PCR assay. CONCLUSION: The VitaPCR™ SARS-CoV-2 is an accurate rapid test, suitable for clinical practice that can be performed as part of a point-of-care testing, for the rapid diagnosis of COVID-19.

Enteroviruses from Humans and Great Apes in the Republic of Congo: Recombination within Enterovirus C Serotypes.

Enteroviruses (EVs) are viruses of the family Picornaviridae that cause mild to severe infections in humans and in several animal species, including non-human primates (NHPs). We conducted a survey and characterization of enteroviruses circulating between humans and great apes in the Congo. Fecal samples (N = 24) of gorillas and chimpanzees living close to or distant from humans in three Congolese parks were collected, as well as from healthy humans (N = 38) living around and within these parks. Enteroviruses were detected in 29.4% of gorilla and 13.15% of human feces, including wild and human-habituated gorillas, local humans and eco-guards. Two identical strains were isolated from two humans coming from two remote regions. Their genomes were similar and all genes showed their close similarity to coxsackieviruses, except for the 3C, 3D and 5'-UTR regions, where they were most similar to poliovirus 1 and 2, suggesting recombination. Recombination events were found between these strains, poliovirus 1 and 2 and EV-C99. It is possible that the same EV-C species circulated in both humans and apes in different regions in the Congo, which must be confirmed in other investigations. In addition, other studies are needed to further investigate the circulation and genetic diversity of enteroviruses in the great ape population, to draw a definitive conclusion on the different species and types of enteroviruses circulating in the Republic of Congo.

SYBR green real-time PCR for the detection of all enterovirus-A71 genogroups.

Enterovirus A71 (EV-A71) has recently become an important public health threat, especially in South-East Asia, where it has caused massive outbreaks of Hand, Foot and Mouth disease every year, resulting in significant mortality. Rapid detection of EV-A71 early in outbreaks would facilitate implementation of prevention and control measures to limit spread. Real-time RT-PCR is the technique of choice for the rapid diagnosis of EV-A71 infection and several systems have been developed to detect circulating strains. Although eight genogroups have been described globally, none of these PCR techniques detect all eight. We describe, for the first time, a SYBR Green real-time RT-PCR system validated to detect all 8 EV-A71 genogroups. This tool could permit the early detection and shift in genogroup circulation and the standardization of HFMD virological diagnosis, facilitating networking of laboratories working on EV-A71 in different regions.

RNA and DNA bacteriophages as molecular diagnosis controls in clinical virology: a comprehensive study of more than 45,000 routine PCR tests.

Real-time PCR techniques are now commonly used for the detection of viral genomes in various human specimens and require for validation both external and internal controls (ECs and ICs). In particular, ICs added to clinical samples are necessary to monitor the extraction, reverse transcription, and amplification steps in order to detect false-negative results resulting from PCR-inhibition or errors in the technical procedure. Here, we performed a large scale evaluation of the use of bacteriophages as ICs in routine molecular diagnosis. This allowed to propose simple standardized procedures (i) to design specific ECs for both DNA and RNA viruses and (ii) to use T4 (DNA) or MS2 (RNA) phages as ICs in routine diagnosis. Various technical formats for using phages as ICs were optimised and validated. Subsequently, T4 and MS2 ICs were evaluated in routine real-time PCR or RT-PCR virological diagnostic tests, using a series of 8,950 clinical samples (representing 36 distinct specimen types) sent to our laboratory for the detection of a variety of DNA and RNA viruses. The frequency of inefficient detection of ICs was analyzed according to the nature of the sample. Inhibitors of enzymatic reactions were detected at high frequency in specific sample types such as heparinized blood and bone marrow (>70%), broncho-alveolar liquid (41%) and stools (36%). The use of T4 and MS2 phages as ICs proved to be cost-effective, flexible and adaptable to various technical procedures of real-time PCR detection in virology. It represents a valuable strategy for enhancing the quality of routine molecular diagnosis in laboratories that use in-house designed diagnostic systems, which can conveniently be associated to the use of specific synthetic ECs. The high rate of inhibitors observed in a variety of specimen types should stimulate the elaboration of improved technical protocols for the extraction and amplification of nucleic acids.

A simple method for molecular detection of Swine-origin and human-origin influenza a virus.

Here we present a real-time one-step reverse transcriptase-polymerase chain reaction SYBR Green assay derived from the method reported by van Elden and collaborators ( 2001 ) that ensures the rapid, sensitive, and cost-effective detection of both seasonal influenza A virus and emerging (H1N1) swine-origin influenza A virus (S-OIV). In addition to this screening test, which successfully detected both seasonal influenza A virus and S-OIV in human clinical samples, we showed that the probe initially designed by van Elden and collaborators could detect seasonal influenza A virus, but not S-OIV; a new probe was designed and tested that specifically detects S-OIV, but not seasonal influenza A. Both probe-based assays were validated by testing human clinical samples and specifically detected either seasonal influenza virus or S-OIV. Finally, in silico analysis of databases predicted that minor modifications of the van Elden primers would facilitate the use of this assay for the broad spectrum detection of all currently characterized variants of influenza A virus, including avian strains.

Novel virus influenza A (H1N1sw) in South-Eastern France, April-August 2009.

BACKGROUND: In April 2009, the first cases of pandemic (H1N1)-2009 influenza [H1N1sw] virus were detected in France. Virological surveillance was undertaken in reference laboratories of the seven French Defence Zones. METHODOLOGY/PRINCIPAL FINDINGS: We report results of virological analyses performed in the Public Hospitals of Marseille during the first months of the outbreak. (i) Nasal swabs were tested using rapid influenza diagnostic test (RIDT) and two RT-PCR assays. Epidemiological characteristics of the 99 first suspected cases were analyzed, including detection of influenza virus and 18 other respiratory viruses. During three months, a total of 1,815 patients were tested (including 236 patients infected H1N1sw virus) and distribution in age groups and results of RIDT were analyzed. (ii) 600 sera received before April 2009 and randomly selected from in-patients were tested by a standard hemagglutination inhibition assay for antibody to the novel H1N1sw virus. (iii) One early (May 2009) and one late (July 2009) viral isolates were characterized by sequencing the complete hemagglutinine and neuraminidase genes. (iiii) Epidemiological characteristics of a cluster of cases that occurred in July 2009 in a summer camp were analyzed. CONCLUSIONS/SIGNIFICANCE: This study presents new virological and epidemiological data regarding infection by the pandemic A/H1N1 virus in Europe. Distribution in age groups was found to be similar to that previously reported for seasonal H1N1. The first seroprevalence data made available for a European population suggest a previous exposure of individuals over 40 years old to influenza viruses antigenically related to the pandemic (H1N1)-2009 virus. Genomic analysis indicates that strains harbouring a new amino-acid pattern in the neuraminidase gene appeared secondarily and tended to supplant the first strains. Finally, in contrast with previous reports, our data support the use of RIDT for the detection of infection in children, especially in the context of the investigation of grouped cases.

Point of care strategy for rapid diagnosis of novel A/H1N1 influenza virus.

BACKGROUND: Within months of the emergence of the novel A/H1N1 pandemic influenza virus (nA/H1N1v), systematic screening for the surveillance of the pandemic was abandoned in France and in some other countries. At the end of June 2009, we implemented, for the public hospitals of Marseille, a Point Of Care (POC) strategy for rapid diagnosis of the novel A/H1N1 influenza virus, in order to maintain local surveillance and to evaluate locally the kinetics of the pandemic. METHODOLOGY/PRINCIPAL FINDINGS: Two POC laboratories, located in strategic places, were organized to receive and test samples 24 h/24. POC strategy consisted of receiving and processing naso-pharyngeal specimens in preparation for the rapid influenza diagnostic test (RIDT) and real-time RT-PCR assay (rtRT-PCR). This strategy had the theoretical capacity of processing up to 36 samples per 24 h. When the flow of samples was too high, the rtRT-PCR test was abandoned in the POC laboratories and transferred to the core virology laboratory. Confirmatory diagnosis was performed in the core virology laboratory twice a day using two distinct rtRT-PCR techniques that detect either influenza A virus or nA/N1N1v. Over a period of three months, 1974 samples were received in the POC laboratories, of which 111 were positive for nA/H1N1v. Specificity and sensitivity of RIDT were 100%, and 57.7% respectively. Positive results obtained using RIDT were transmitted to clinical practitioners in less than 2 hours. POC processed rtRT-PCR results were available within 7 hours, and rtRT-PCR confirmation within 24 hours. CONCLUSIONS/SIGNIFICANCE: The POC strategy is of benefit, in all cases (with or without rtRT-PCR assay), because it provides continuous reception/processing of samples and reduction of the time to provide consolidated results to the clinical practitioners. We believe that implementation of the POC strategy for the largest number of suspect cases may improve the quality of patient care and our knowledge of the epidemiology of the pandemic.

Point of care strategy for rapid diagnosis of novel A/H1N1 influenza virus.

In late June 2009, we implemented for public hospitals of Marseille Point Of Care strategy for rapid diagnosis of novel A/H1N1 influenza virus. During two months, we have tested more than 900 specimens in both Point Of Care laboratories. We believe that implementation of Point of Care strategy for the largest number of suspects cases may improve quality of patients care and our knowledge of the epidemiology of the pandemic.