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1.
Viruses ; 16(5)2024 May 03.
Article in English | MEDLINE | ID: mdl-38793608

ABSTRACT

In 2022, an unprecedented outbreak of mpox raged in several nations. Sequences from the 2022 outbreak reveal a higher nucleotide substitution if compared with the estimated rate for orthopoxviruses. Recently, intra-lesion SNVs (single nucleotide variants) have been described, and these have been suggested as possible sources of genetic variation. Until now, it has not been clear if the presence of several SNVs could represents the result of local mutagenesis or a possible co-infection. We investigated the significance of SNVs through whole-genome sequencing analysis of four unrelated mpox cases. In addition to the known mutations harboured by the circulating strains of virus (MPXV), 7 novel mutations were identified, including SNVs located in genes that are involved in immune evasion mechanisms and/or viral fitness, six of these appeared to be APOBEC3-driven. Interestingly, three patients exhibited the coexistence of mutated and wild-type alleles for five non-synonymous variants. In addition, two patients, apparently unrelated, showed an analogous pattern for two novel mutations, albeit with divergent frequencies. The coexistence of mixed viral populations, harbouring non-synonymous mutations in patients, supports the hypothesis of possible co-infection. Additional investigations of larger clinical cohorts are essential to validating intra-patient viral genome heterogeneity and determining the possibility of co-presence events of slightly divergent MPXV strains.


Subject(s)
Disease Outbreaks , Genome, Viral , Mutation , Whole Genome Sequencing , Humans , Italy/epidemiology , Male , Orthopoxvirus/genetics , Orthopoxvirus/classification , Poxviridae Infections/virology , Poxviridae Infections/epidemiology , Poxviridae Infections/veterinary , Female , Coinfection/virology , Coinfection/epidemiology , Phylogeny , Polymorphism, Single Nucleotide , Middle Aged , Genetic Variation
2.
Viruses ; 16(5)2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38793539

ABSTRACT

With the continuous spread of new SARS-CoV-2 variants of concern (VOCs), the monitoring of diagnostic test performances is mandatory. We evaluated the changes in antigen diagnostic tests' (ADTs) accuracy along the Delta to Omicron VOCs transition, exploring the N protein mutations possibly affecting ADT sensitivity and assessing the best sampling site for the diagnosis of Omicron infections. In total, 5175 subjects were enrolled from 1 October 2021 to 15 July 2022. The inclusion criteria were SARS-CoV-2 ADT combined with a same-day RT-PCR swab test. For the sampling site analysis, 61 patients were prospectively recruited during the Omicron period for nasal and oral swab analyses by RT-PCR. Next-Generation Sequencing data were obtained to evaluate the different sublineages. Using RT-PCR as a reference, 387 subjects resulted in becoming infected and the overall sensitivity of the ADT decreased from 63% in the Delta period to 33% in the Omicron period. This decrease was highly statistically significant (p < 0.001), and no decrease in viral load was detected at the RNA level. The nasal site presented a significantly higher viral load than the oral site during the Omicron wave. The reduced detection rate of Omicron infections by ADT should be considered in the global testing strategy to preserve accurate diagnoses across the changing SARS-CoV-2 variants.


Subject(s)
COVID-19 , SARS-CoV-2 , Sensitivity and Specificity , Humans , SARS-CoV-2/immunology , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19/virology , COVID-19/immunology , Male , Viral Load , Female , Antigens, Viral/immunology , COVID-19 Serological Testing/methods , Mutation , Middle Aged , Adult , Prospective Studies , RNA, Viral/genetics , Aged
3.
Viruses ; 16(1)2024 01 08.
Article in English | MEDLINE | ID: mdl-38257798

ABSTRACT

Toscana virus (TOSV), a sandfly-borne virus, is an important etiological agent in human acute meningitis and meningoencephalitis in the Mediterranean area during the summer. However, the actual number of TOSV infections is underestimated. Laboratory confirmation is necessary because TOSV infection has overlapping clinical features with other neuro-invasive viral infections. Nowadays, the reference test for direct diagnosis in the acute phase of TOSV infection is the PCR based method for detecting TOSV in cerebrospinal fluid and/or plasma, serum, or blood. Although poorly employed, urine is another helpful biological matrix for TOSV detection. Urine is a matrix rich in PCR inhibitors that affect PCR efficiency; consequently, false negatives could be generated. To investigate the potential effect of urine PCR inhibitors on TOSV detection, we compared undiluted and diluted urine using 10-fold series of spiked TOSV. The results showed a significant improvement in TOSV detection performance in diluted urine (1 TCID50 vs. 1 × 104 TCID50 limit of detection and 101.35% vs. 129.62% efficiency, respectively, in diluted and undiluted urine). In conclusion, our data provide preliminary important insights into the use of diluted urine to limit the impact of the inhibitory effects of urine on the detection of TOSV in RT-PCR-based approaches.


Subject(s)
Body Fluids , Encephalitis, California , Sandfly fever Naples virus , Humans , Sandfly fever Naples virus/genetics , Plasma , Laboratories
4.
Philos Trans R Soc Lond B Biol Sci ; 379(1894): 20230004, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38008122

ABSTRACT

The Strongyloides genus of parasitic nematodes have a fascinating life cycle and biology, but are also important pathogens of people and a World Health Organization-defined neglected tropical disease. Here, a community of Strongyloides researchers have posed thirteen major questions about Strongyloides biology and infection that sets a Strongyloides research agenda for the future. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.


Subject(s)
Life Cycle Stages , Strongyloides , Animals , Humans
5.
Life Sci Alliance ; 6(12)2023 12.
Article in English | MEDLINE | ID: mdl-37748810

ABSTRACT

During the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), positive-sense genomic RNA and subgenomic RNAs (sgRNAs) are synthesized by a discontinuous process of transcription characterized by a template switch, regulated by transcription-regulating sequences (TRS). Although poorly known about makeup and dynamics of sgRNAs population and function of its constituents, next-generation sequencing approaches with the help of bioinformatics tools have made a significant contribution to expand the knowledge of sgRNAs in SARS-CoV-2. For this scope to date, Periscope, LeTRS, sgDI-tector, and CORONATATOR have been developed. However, limited number of studies are available to compare the performance of such tools. To this purpose, we compared Periscope, LeTRS, and sgDI-tector in the identification of canonical (c-) and noncanonical (nc-) sgRNA species in the data obtained with the Illumina ARTIC sequencing protocol applied to SARS-CoV-2-infected Caco-2 cells, sampled at different time points. The three software showed a high concordance rate in the identification and in the quantification of c-sgRNA, whereas more differences were observed in nc-sgRNA. Overall, LeTRS and sgDI-tector result to be adequate alternatives to Periscope to analyze Fastq data from sequencing platforms other than Nanopore.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , Subgenomic RNA , Caco-2 Cells , Computational Biology , RNA
6.
PLoS Negl Trop Dis ; 17(7): e0011465, 2023 07.
Article in English | MEDLINE | ID: mdl-37410782

ABSTRACT

BACKGROUND: Female Genital Schistosomiasis (FGS) is a neglected disease of the genital tract due to the inflammatory response to the presence of Schistosoma haematobium eggs in the genital tract. The WHO has prioritized the improvement of diagnostics for FGS and previous studies have explored the PCR-based detection of Schistosoma DNA on genital specimens, with encouraging results. This study aimed to determine the prevalence of FGS among women living in an endemic district in North-western Tanzania, using PCR on samples collected though cervical-vaginal swabs, and to compare the performance of self-collected and healthcare worker-collected (operator-collected) samples, and the acceptability of the different sampling methods. METHODS/PRINCIPAL FINDINGS: A cross-sectional study was conducted involving 211 women living in 2 villages in the Maswa district of North-western Tanzania. Urine, self-collected and operator-collected cervical-vaginal swabs were obtained from participants. A questionnaire was administered, focusing on the comfortability in undergoing different diagnostic procedures. Prevalence of urinary schistosomiasis, as assessed by eggs in urine, was 8.5% (95%CI 5.1-13.1). DNA was pre-isolated from genital swabs and transported at room temperature to Italy for molecular analysis. Prevalence of active schistosomiasis, urinary schistosomiasis, and FGS were 10.0% (95% CI 6.3-14.8), 8.5% (95%CI 5.1-13.1), and 4.7% (95%CI 2.3-8.5), respectively. When real-time PCR was performed after a pre-amplification step, the prevalence of active schistosomiasis increased to 10.4% (95%CI 6.7-15.4), and FGS to 5.2% (95%CI 2.6-9.1). Of note, more cases were detected by self-collected than operator-collected swabs. The vast majority of participants (95.3%) declared that they were comfortable/very comfortable about genital self-sampling, which was indicated as the preferred sampling method by 40.3% of participants. CONCLUSIONS/SIGNIFICANCE: The results of this study show that genital self-sampling followed by pre-amplified PCR on room temperature-stored DNA is a useful method from both technical and acceptability point of views. This encourages further studies to optimize samples processing, and identify the best operational flow to allow integration of FGS screening into women health programmes, such as HPV screening.


Subject(s)
Genitalia, Female , Schistosomiasis haematobia , Animals , Female , Humans , Male , Prevalence , Tanzania/epidemiology , Cross-Sectional Studies , Schistosomiasis haematobia/diagnosis , Schistosomiasis haematobia/epidemiology , Schistosomiasis haematobia/urine , Schistosoma haematobium/genetics , Real-Time Polymerase Chain Reaction
7.
Asp Mol Med ; 1: 100008, 2023.
Article in English | MEDLINE | ID: mdl-37519862

ABSTRACT

Like for other coronaviruses, SARS-CoV-2 gene expression strategy is based on the synthesis of a nested set of subgenomic mRNA species (sgRNAs). These sgRNA are synthesized using a "discontinuous transcription" mechanism that relies on template switching at Transcription Regulatory Sequences (TRS). Both canonical (c-sgRNA) and non-canonical (nc-sgRNA, less numerous) subgenomic RNA species can be produced. Currently, sgRNAs are investigated on the basis of sequence data obtained through next generation sequencing (NGS), and bioinformatic tools are crucial for their identification, characterization and quantification. To date, few software have been developed to this aim, whose reliability and applicability to all the available NGS platforms need to be established, to build confidence on the information resulting from such tools. In fact, these information may be crucial for the in depth elucidation of viral expression strategy, particularly in respect of the significance of nc-sgRNAs, and for the possible use of sgRNAs as potential markers of virus replicative activity in infected patients.

8.
Diagnostics (Basel) ; 13(7)2023 Apr 04.
Article in English | MEDLINE | ID: mdl-37046567

ABSTRACT

BACKGROUND: Monkeypox virus (MPXV) is a double-stranded DNA virus belonging to the orthopoxvirus genus in the family Poxviridae. Distinct clades are identified: the clade I belonging to the Central African (or Congo Basin) clade and the subclades IIa and IIb belonging to the West African clade. Here, a commercial droplet digital PCR (ddPCR) assay was evaluated for the quantification of the MPXV West Africa clade in clinical samples. METHODS: The ddPCR reaction was assessed as a duplex assay using RPP30 as an internal amplification control. A total of 60 clinical specimens were tested, 40 positives (skin lesions, n=10; rectal swabs, n = 10; pharyngeal swabs, n = 10; and whole blood, n = 10), and 20 negatives (n = 5 for each biological matrix) were found at the routine molecular diagnostics (orthopoxvirus qPCR followed by confirmation with Sanger sequencing). To evaluate the analytical sensitivity, the ddPCR reaction was first analyzed on serial dilutions of synthetic DNA spiked in water and in negative biological matrices, achieving a limit of detection of 3.5 copy/µL. RESULTS: Regarding the clinical samples, compared to routine molecular diagnostics, the ddPCR duplex assay showed 100% of specificity for all biological matrices and 100% sensitivity (10/10) for lesions, 100% (10/10) for rectal swabs, 90% (9/10) for pharyngeal swabs, and 60% (6/10) for whole blood. CONCLUSION: Overall, our data showed that the commercial ddPCR assay allowed the DNA detection of MPXV in 87.5% (35/40) of our cohort, highlighting useful technical indications for the different specimens with a potential greatest performance for skin lesions and rectal swabs.

9.
Pathogens ; 12(2)2023 Jan 20.
Article in English | MEDLINE | ID: mdl-36839437

ABSTRACT

Coupled with its rarity in non-endemic areas, the clinical heterogeneity of leprosy makes diagnosis very challenging. We report a diagnosis of multibacillary leprosy in a 22-year-old Indian woman, adopted at the age of 10 and living in Italy. The patient presented with painful skin lesions on the face, trunk, and lower and upper extremities, associated with dysesthesia and a motor deficit in her left leg following corticosteroid therapy interruption. Histopathology results from the skin lesions suggested leprosy, but no acid-fast bacilli were identified. Molecular biology in a center specializing in tropical diseases confirmed the diagnosis, allowing prompt and adequate treatment. Genotype analysis allowed the identification of a genotype 1D of M. leprae, facilitating the epidemiological investigation of the plausible infection origin. No resistances to rifampicin, dapsone, or ofloxacin were detected. Leprosy will continue to exist in high-income nations, and the incidence may rise over time due to increasing migration and globalization. CARE guidelines were followed.

11.
Sci Rep ; 12(1): 9957, 2022 06 15.
Article in English | MEDLINE | ID: mdl-35705621

ABSTRACT

Strongyloidiasis is a neglected tropical disease caused by the soil-transmitted nematode by Strongyloides stercoralis, that affects approximately 600 million people worldwide. In immunosuppressed individuals disseminated strongyloidiasis can rapidly lead to fatal outcomes. There is no gold standard for diagnosing strongyloidiasis, and infections are frequently misdiagnosed. A better understanding of the molecular biology of this parasite can be useful for example for the discovery of potential new biomarkers. Interestingly, recent evidence showed the presence of small RNAs in Strongyloididae, but no data was provided for S. stercoralis. In this study, we present the first identification of miRNAs of both L1 and iL3 larval stages of S. stercoralis. For our purpose, the aims were: (i) to analyse the miRNome of L1 and iL3 S. stercoralis and to identify potential miRNAs of this nematode, (ii) to obtain the mRNAs profiles in these two larval stages and (iii) to predict potential miRNA target sites in mRNA sequences. Total RNA was isolated from L1 and iL3 collected from the stool of 5 infected individuals. For the miRNAs analysis, we used miRDeep2 software and a pipeline of bio-informatic tools to construct a catalog of a total of 385 sequences. Among these, 53% were common to S. ratti, 19% to S. papillosus, 1% to Caenorhabditis elegans and 44% were novel. Using a differential analysis between the larval stages, we observed 6 suggestive modulated miRNAs (STR-MIR-34A-3P, STR-MIR-8397-3P, STR-MIR-34B-3P and STR-MIR-34C-3P expressed more in iL3, and STR-MIR-7880H-5P and STR-MIR-7880M-5P expressed more in L1). Along with this analysis, we obtained also the mRNAs profiles in the same samples of larvae. Multiple testing found 81 statistically significant mRNAs of the total 1553 obtained (FDR < 0.05; 32 genes expressed more in L1 than iL3; 49 genes expressed more in L3 than iL1). Finally, we found 33 predicted mRNA targets of the modulated miRNAs, providing relevant data for a further validation to better understand the role of these small molecules in the larval stages and their valuein clinical diagnostics.


Subject(s)
MicroRNAs , Strongyloides stercoralis , Strongyloidiasis , Animals , Feces/parasitology , Humans , Larva/genetics , MicroRNAs/genetics , RNA, Messenger , Strongyloides stercoralis/genetics , Strongyloidiasis/diagnosis , Strongyloidiasis/genetics , Strongyloidiasis/parasitology
13.
Microorganisms ; 10(4)2022 Apr 02.
Article in English | MEDLINE | ID: mdl-35456819

ABSTRACT

Tropheryma whipplei (TW), Helicobacter pylori (HP), and intestinal protozoa (IP) are widespread pathogens with similar routes of transmission and epidemiological risk factors. Epidemiological data on co-infection between TW, HP, and IP are scarce. We aim to more deeply investigate the co-infection rate for these pathogens, evaluating the risk factors and symptoms. Methods: This is a cross-sectional study conducted at the IRCCS Sacro Cuore Don Calabria Hospital in Northern Italy, a referral center for tropical and Whipple's disease (WD). Stored stool samples from 143 subjects previously tested for TW DNA by real-time PCR were explored for HP and IP DNA detection. The virulence factor cagA was investigated in HP-positive patients. Results: A history of migration was reported significantly more in TW-positive than in negative subjects (34.1% vs. 9.1%, p = 0.001) and in HP-infected than in those non-infected (59.1% vs. 9.1%, p < 0.001). The HP infection rate differed significantly between TW-infected and uninfected groups (31.8% vs. 8.1%, p = 0.001), while no difference was observed for IP infection. Significantly higher TW intestinal colonization was found in HP-infected patients than in non-infected (63.6% vs. 24.8%, p < 0.001). In addition, the proportion of Blastocysts positive finding was also significantly higher in HP-infected than in non-infected (40.9% vs. 17.4%, p = 0.018). Conclusions: The present study is the first to report a high TW and HP co-infection rate. To reduce the risk of morbidity from a chronic infection of either pathogen, clinicians may consider TW-HP molecular screening on the same stool sample for patients with suspected HP disease or WD, particularly in case of travel history.

14.
Int J Antimicrob Agents ; 59(2): 106516, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34999239

ABSTRACT

High concentrations of ivermectin demonstrated antiviral activity against SARS-CoV-2 in vitro. The aim of this study was to assess the safety and efficacy of high-dose ivermectin in reducing viral load in individuals with early SARS-CoV-2 infection. This was a randomised, double-blind, multicentre, phase II, dose-finding, proof-of-concept clinical trial. Participants were adults recently diagnosed with asymptomatic/oligosymptomatic SARS-CoV-2 infection. Exclusion criteria were: pregnant or lactating women; CNS disease; dialysis; severe medical condition with prognosis <6 months; warfarin treatment; and antiviral/chloroquine phosphate/hydroxychloroquine treatment. Participants were assigned (ratio 1:1:1) according to a randomised permuted block procedure to one of the following arms: placebo (arm A); single-dose ivermectin 600 µg/kg plus placebo for 5 days (arm B); and single-dose ivermectin 1200 µg/kg for 5 days (arm C). Primary outcomes were serious adverse drug reactions (SADRs) and change in viral load at Day 7. From 31 July 2020 to 26 May 2021, 32 participants were randomised to arm A, 29 to arm B and 32 to arm C. Recruitment was stopped on 10 June because of a dramatic drop in cases. The safety analysis included 89 participants and the change in viral load was calculated in 87 participants. No SADRs were registered. Mean (S.D.) log10 viral load reduction was 2.9 (1.6) in arm C, 2.5 (2.2) in arm B and 2.0 (2.1) in arm A, with no significant differences (P = 0.099 and 0.122 for C vs. A and B vs. A, respectively). High-dose ivermectin was safe but did not show efficacy to reduce viral load.


Subject(s)
Antiviral Agents/pharmacokinetics , COVID-19 Drug Treatment , Ivermectin/pharmacokinetics , SARS-CoV-2/drug effects , Adult , Antiparasitic Agents/blood , Antiparasitic Agents/pharmacokinetics , Antiparasitic Agents/pharmacology , Antiviral Agents/blood , Antiviral Agents/pharmacology , COVID-19/blood , COVID-19/virology , Double-Blind Method , Drug Repositioning , Female , Humans , Ivermectin/blood , Ivermectin/pharmacology , Male , Middle Aged , SARS-CoV-2/growth & development , SARS-CoV-2/pathogenicity , Treatment Outcome , Viral Load/drug effects
15.
Microorganisms ; 9(8)2021 Aug 14.
Article in English | MEDLINE | ID: mdl-34442817

ABSTRACT

SARS-CoV-2 infection was monitored in 1898 health care workers (HCWs) after receiving full vaccination with BNT162b2. Untill 30 June 2021, 10 HCWs tested positive for SARS-CoV-2 using real time RT-PCR, resulting in a 4-month cumulative incidence of 0.005%. The infection was mildly symptomatic in six (60%) and asymptomatic in four (40%) individuals. Among the infected HCWs, eight consenting individuals provided paired NPS and saliva during the course of infection, for the purpose of the analysis performed in the present study. Genomic and subgenomic viral RNAs were investigated using real-time RT-PCR in both biological specimens. The temporal profile of viral load was measured using ddPCR. Viral mutations were also analysed. Subgenomic viral RNA was detected in 8/8 (100%) NPS and in 6/8 (75%) saliva specimens at the baseline. The expression of subgenomic RNA was observed for up to 7 days in 3/8 (38%) symptomatic cases. Moreover, concordance was observed between NPS and saliva in the detection of viral mutations, and both N501Y and 69/70del (associated with the B.1.1.7 variant) were detected in the majority 6/8 (75%) of subjects, while the K417T mutation (associated with the P.1-type variants) was detected in 2/8 (25%) individuals. Overall, our findings report a low frequency of infected HCWs after full vaccination. It is, therefore, important to monitor the vaccinees in order to identify asymptomatic infected individuals. Saliva can be a surrogate for SARS-CoV-2 surveillance, particularly in social settings such as hospitals.

16.
Expert Rev Mol Diagn ; 21(6): 591-612, 2021 06.
Article in English | MEDLINE | ID: mdl-33910444

ABSTRACT

Introduction: Molecular technology has played an important role in arboviruses diagnostics. PCR-based methods stand out in terms of sensitivity, specificity, cost, robustness, and accessibility, and especially the isothermal amplification (IA) method is ideal for field-adaptable diagnostics in resource-limited settings (RLS).Areas covered: In this review, we provide an overview of the various molecular methods for West Nile, Zika, Dengue and Chikungunya. We summarize literature works reporting the assessment and use of in house and commercial assays. We describe limitations and challenges in the usage of methods and opportunities for novel approaches such as NNext-GenerationSequencing (NGS).Expert opinion: The rapidity and accuracy of differential diagnosis is essential for a successful clinical management, particularly in co-circulation area of arboviruses. Several commercial diagnostic molecular assays are available, but many are not affordable by RLS and not usable as Point-of-care/Point-of-need (POC/PON) such as RReal-TimeRT-PCR, Array-based methods and NGS. In contrast, the IA-based system fits better for POC/PON but it is still not ideal for the multiplexing detection system. Improvement in the characterization and validation of current molecular assays is needed to optimize their translation to the point of care.


Subject(s)
Arboviruses , Chikungunya Fever , Dengue , Zika Virus Infection , Zika Virus , Arboviruses/genetics , Chikungunya Fever/diagnosis , Dengue/diagnosis , Genomics , Humans , RNA, Viral/genetics , Zika Virus/genetics , Zika Virus Infection/diagnosis
17.
Genomics ; 113(4): 1628-1638, 2021 07.
Article in English | MEDLINE | ID: mdl-33839270

ABSTRACT

Sequencing the SARS-CoV-2 genome from clinical samples can be challenging, especially in specimens with low viral titer. Here we report Accurate SARS-CoV-2 genome Reconstruction (ACoRE), an amplicon-based viral genome sequencing workflow for the complete and accurate reconstruction of SARS-CoV-2 sequences from clinical samples, including suboptimal ones that would usually be excluded even if unique and irreplaceable. The protocol was optimized to improve flexibility and the combination of technical replicates was established as the central strategy to achieve accurate analysis of low-titer/suboptimal samples. We demonstrated the utility of the approach by achieving complete genome reconstruction and the identification of false-positive variants in >170 clinical samples, thus avoiding the generation of inaccurate and/or incomplete sequences. Most importantly, ACoRE was crucial to identify the correct viral strain responsible of a relapse case, that would be otherwise mis-classified as a re-infection due to missing or incorrect variant identification by a standard workflow.


Subject(s)
COVID-19/genetics , Genome, Viral/genetics , Reinfection/genetics , SARS-CoV-2/genetics , COVID-19/pathology , COVID-19/virology , Genetic Variation/genetics , Humans , Reinfection/pathology , Reinfection/virology , SARS-CoV-2/pathogenicity , Whole Genome Sequencing
18.
Clin Microbiol Infect ; 27(1): 131.e1-131.e3, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33059091

ABSTRACT

OBJECTIVES: In Italy the burden of patients with coronavirus disease 2019 (COVID-19) gradually decreased from March to the end of May. In this work we aimed to evaluate a possible association between the severity of clinical manifestations and viral load over time during the epidemiological transition from high-to low-transmission settings. METHODS: We reviewed the cases of COVID-19 diagnosed at the emergency room of our hospital, retrieving the proportion of patients admitted to the intensive care unit. A raw estimation of the viral load was done evaluating the Ct (cycle threshold) trend obtained from our diagnostic reverse transcriptase real-time PCR test. RESULTS: The proportion of patients requiring intensive care significantly decreased from 6.7% (19/281) in March to 1.1% (1/86) in April, and to none in May (Fisher's test p 0.0067). As for viral load, we observed a trend of Ct increasing from a median value of 24 (IQR 19-29) to 34 (IQR 29-37) between March and May, with a statistically significant difference between March and April (pairwise Wilcoxon test with stepdown Bonferroni adjustment for multiple testing, p 0.0003). CONCLUSIONS: We observed a reduction over time in the proportion of patients with COVID-19 requiring intensive care, along with decreasing median values of viral load. As the epidemiological context changes from high-to low-transmission settings, people are presumably exposed to a lower viral load which has been previously associated with less severe clinical manifestations.


Subject(s)
COVID-19/epidemiology , COVID-19/physiopathology , Pandemics , SARS-CoV-2/genetics , Aged , Aged, 80 and over , COVID-19/diagnosis , COVID-19/transmission , COVID-19 Testing , Emergency Service, Hospital , Female , Hospitals , Humans , Intensive Care Units , Italy/epidemiology , Male , Middle Aged , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/pathogenicity , Severity of Illness Index , Viral Load
19.
Microorganisms ; 8(11)2020 Oct 30.
Article in English | MEDLINE | ID: mdl-33143253

ABSTRACT

Chagas disease, a neglected protozoal disease endemic in Latin America, is also currently considered an emerging threat in nonendemic areas because of population movements. The detection of Trypanosoma cruzi DNA is increasingly being considered as important evidence to support Chagas disease diagnoses. However, further performance evaluation of molecular assays is useful for a standardization of strategy considering the whole process in routine diagnosis, especially for the different settings such as endemic and nonendemic countries. Seventy-five samples were collected from subjects screened for Chagas disease in Italy. The DNA was isolated from blood using automated extraction. We evaluated the performance of the commercial RealCycler® CHAG kit (pmPCR) based on satellite DNA (SatDNA) and of an in-house real-time PCR (ihPCR) targeting Sat and kinetoplast (k) DNAs, using the concordance of two serology assays as a reference standard. The sensitivity of kDNA and SatDNA tests by ihPCR and SatDNA by pmPCR were 14.29% (95% confidence interval (CI) 6.38 to 26.22), 7.14% (95% CI 1.98 to 17.29), and 7.14% (95% CI 1.98 to 17.29), respectively. Specificity was 100% for all PCR assays and targets. Overall, our results suggest that the preferred approach for clinical laboratories is to combine the kDNA and SatDNA as targets in order to minimize false-negative results increasing sensitivity.

20.
Sci Rep ; 10(1): 18764, 2020 10 30.
Article in English | MEDLINE | ID: mdl-33127953

ABSTRACT

Droplet digital PCR (ddPCR) is a sensitive and reproducible technology widely used for quantitation of several viruses. The aim of this study was to evaluate the 2019-nCoV CDC ddPCR Triplex Probe Assay (BioRad) performance, comparing the direct quantitation of SARS-CoV-2 on nasopharyngeal swab with the procedure applied to the extracted RNA. Moreover, two widely used swab types were compared (UTM 3 mL and ESwab 1 mL, COPAN). A total of 50 nasopharyngeal swabs (n = 25 UTM 3 mL and n = 25 ESwab 1 mL) from SARS-CoV-2 patients, collected during the pandemic at IRCCS Sacro Cuore Don Calabria Hospital (Veneto Region, North-East Italy), were used for our purpose. After heat inactivation, an aliquot of swab medium was used for the direct quantitation. Then, we compared the direct method with the quantitation performed on the RNA purified from nasopharyngeal swab by automated extraction. We observed that the direct approach achieved generally equal RNA copies compared to the extracted RNA. The results with the direct quantitation were more accurate on ESwab with a sensitivity of 93.33% [95% CI, 68.05 to 99.83] and specificity of 100.00% for both N1 and N2. On the other hand, on UTM we observed a higher rate of discordant results for N1 and N2. The human internal amplification control (RPP30) showed 100% of both sensitivity and specificity independent of swabs and approaches. In conclusion, we described a direct quantitation of SARS-CoV-2 in nasopharyngeal swab. Our approach resulted in an efficient quantitation, without automated RNA extraction and purification. However, special care needs to be taken on the potential bias due to the conservation of samples and to the heating treatment, as we used thawed and heat inactivated material. Further studies on a larger cohort of samples are warranted to evaluate the clinical value of this direct approach.


Subject(s)
Clinical Laboratory Techniques/methods , Multiplex Polymerase Chain Reaction/methods , Betacoronavirus/genetics , Betacoronavirus/pathogenicity , COVID-19 Testing , Clinical Laboratory Techniques/standards , Coronavirus Infections/diagnosis , Humans , Limit of Detection , Multiplex Polymerase Chain Reaction/standards , Reproducibility of Results , Respiratory Mucosa/virology , SARS-CoV-2
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