Investigations, actions and learning from an outbreak of SARS-CoV-2 infection among healthcare workers in the United Kingdom

Background: We report an outbreak of SARS coronavirus-2 (SARS-CoV-2) infection among healthcare workers (HCW) in an NHS elective healthcare facility. Methodology: A narrative chronological account of events after declaring an outbreak of SARS-CoV-2 among HCWs. As part of the investigations, HCWs were offered testing during the outbreak. These were: (1) screening by real-time reverse transcriptase polymerase chain reaction (RT- PCR) to detect a current infection; and (2) serum samples to determine seroprevalence. Results: Over 180 HCWs were tested by real-time RT-PCR for SARS-CoV-2 infection. The rate of infection was 15.2% (23.7% for clinical or directly patient-facing HCWs vs. 4.8% in non-clinical non-patient-facing HCWs). Of the infected HCWs, 57% were asymptomatic. Seroprevalence (SARS-CoV-2 IgG) among HCWs was 13%. It was challenging to establish an exact source for the outbreak. The importance of education, training, social distancing and infection prevention practices were emphasised. Additionally, avoidance of unnecessary transfer of patients and minimising cross-site working for staff and early escalation were highlighted. Establishing mass and regular screening for HCWs are also crucial to enabling the best care for patients while maintaining the wellbeing of staff. Conclusion: To our knowledge, this is the first UK outbreak report among HCWs and we hope to have highlighted some key issues and learnings that can be considered by other NHS staff and HCWs globally when dealing with such a task in future.

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Performance of Real-Time Reverse Transcription Polymerase Chain Reaction for the Detection of Foot-and-Mouth Disease Virus during Field Outbreaks in the United Kingdom in 2007

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063870902100303 ◽

2009 ◽

Vol 21 (3) ◽

pp. 321-330 ◽

Cited By ~ 33

Author(s):

Scott M. Reid ◽

Katja Ebert ◽

Katarzyna Bachanek-Bankowska ◽

Carrie Batten ◽

Anna Sanders ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

United Kingdom ◽

Real Time ◽

Reverse Transcription ◽

Foot And Mouth Disease ◽

Rt Pcr ◽

Chain Reaction ◽

Pcr Assay ◽

The United Kingdom ◽

Polymerase Chain

Rapid and accurate diagnosis is essential for effective control of foot-and-mouth disease (FMD). The present report describes the practical steps undertaken to deploy a real-time reverse transcription polymerase chain reaction (real-time RT-PCR) to process the samples received during the outbreaks of FMD in the United Kingdom in 2007. Two independent real-time RT-PCR assays targeting different regions (5′UTR and 3D) of the FMD virus (FMDV) genome were used to confirm the presence of FMDV in clinical samples collected from the first infected premises. Once the FMDV strain responsible had been sequenced, a single real-time RT-PCR assay (3D) was selected to test a total of 3,216 samples, including material from all 8 infected premises. Using a 96-well automated system to prepare nucleic acid template, up to 84 samples could be processed within 5 hr of submission, and up to 269 samples were tested per working day. A conservative cut-off was used to designate positive samples, giving rise to an assay specificity of 99.9% or 100% for negative control material or samples collected from negative premises, respectively. For the first time, real-time RT-PCR results were used to recognize preclinical FMD in a cattle herd. Furthermore, during the later stages of the outbreaks, the real-time RT-PCR assay supported an active surveillance program within high-risk cattle herds. To the authors' knowledge, this is the first documented use of real-time RT-PCR as a principal laboratory diagnostic tool following introduction of FMD into a country that was FMD-free (without vaccination) and highlights the advantages of this assay to support control decisions during disease outbreaks.

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1504: Molecular Diagnosis and Staging of Prostate Cancer Using Clusterin in Real Time Reverse Transcription Polymerase Chain Reaction (RT-PCR)

The Journal of Urology ◽

10.1016/s0022-5347(18)33708-x ◽

2006 ◽

Vol 175 (4S) ◽

pp. 485-486

Author(s):

Sabarinath B. Nair ◽

Christodoulos Pipinikas ◽

Roger Kirby ◽

Nick Carter ◽

Christiane Fenske

Keyword(s):

Prostate Cancer ◽

Polymerase Chain Reaction ◽

Real Time ◽

Molecular Diagnosis ◽

Reverse Transcription ◽

Rt Pcr ◽

Chain Reaction ◽

Polymerase Chain

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Anomaly Identification during Polymerase Chain Reaction for Detecting SARS-CoV-2 Using Artificial Intelligence Trained from Simulated Data

Molecules ◽

10.3390/molecules26010020 ◽

2020 ◽

Vol 26 (1) ◽

pp. 20

Author(s):

Reynaldo Villarreal-González ◽

Antonio J. Acosta-Hoyos ◽

Jaime A. Garzon-Ochoa ◽

Nataly J. Galán-Freyle ◽

Paola Amar-Sepúlveda ◽

...

Keyword(s):

Artificial Intelligence ◽

Big Data ◽

Real Time ◽

Binary Classification ◽

Simulated Data ◽

Classification Model ◽

Rt Pcr ◽

Simon Bolivar ◽

Polymerase Chain ◽

Available Information

Real-time reverse transcription (RT) PCR is the gold standard for detecting Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), owing to its sensitivity and specificity, thereby meeting the demand for the rising number of cases. The scarcity of trained molecular biologists for analyzing PCR results makes data verification a challenge. Artificial intelligence (AI) was designed to ease verification, by detecting atypical profiles in PCR curves caused by contamination or artifacts. Four classes of simulated real-time RT-PCR curves were generated, namely, positive, early, no, and abnormal amplifications. Machine learning (ML) models were generated and tested using small amounts of data from each class. The best model was used for classifying the big data obtained by the Virology Laboratory of Simon Bolivar University from real-time RT-PCR curves for SARS-CoV-2, and the model was retrained and implemented in a software that correlated patient data with test and AI diagnoses. The best strategy for AI included a binary classification model, which was generated from simulated data, where data analyzed by the first model were classified as either positive or negative and abnormal. To differentiate between negative and abnormal, the data were reevaluated using the second model. In the first model, the data required preanalysis through a combination of prepossessing. The early amplification class was eliminated from the models because the numbers of cases in big data was negligible. ML models can be created from simulated data using minimum available information. During analysis, changes or variations can be incorporated by generating simulated data, avoiding the incorporation of large amounts of experimental data encompassing all possible changes. For diagnosing SARS-CoV-2, this type of AI is critical for optimizing PCR tests because it enables rapid diagnosis and reduces false positives. Our method can also be used for other types of molecular analyses.

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COVID-19 serological testing for Healthcare Workers in Lombardy, Italy

European Journal of Public Health ◽

10.1093/eurpub/ckaa165.351 ◽

2020 ◽

Vol 30 (Supplement_5) ◽

Author(s):

G Del Castillo ◽

A Castrofino ◽

F Grosso ◽

A Barone ◽

L Crottogini ◽

...

Keyword(s):

Healthcare Workers ◽

Geographical Area ◽

Healthcare Facility ◽

Nasopharyngeal Swab ◽

Infection Prevalence ◽

Serological Testing ◽

Prevention Policy ◽

Rt Pcr ◽

Serological Tests ◽

Screening Process

Abstract Issue COVID-19 pandemic began in Italy on February 20th, 2020. Since the beginning of the emergency Healthcare Workers' (HCWs) involvement was prominent, mainly due to direct assistance to COVID-19 patients. Therefore, we implemented a prevention policy for HCW screening through serological and RT-PCR testing. Description of the problem HCW screening for SARS-CoV-2 infection is essential for prevention and control of the pandemic. Lombardy's Healthcare authorities settled a screening process for HCWs divided into three steps: 1) body temperature assessment at the beginning and the end of work shift, if fever > 37.5 °C was present the HCW was sent back home and a nasopharyngeal swab was performed; 2) progressive recruitment for serological testing; 3) on those positive to IgG a nasopharyngeal swab was performed and tested for viral RNA by RT-PCR. Results Among 79185 HCW tested, 9589 (12%) were positive on serological IgG testing. Of the 9589 positive a nasopharyngeal swab was performed on 6884. Of these 358 (5%) tested positive and the remaining 6526 (95%) negative to RT-PCR. We calculated a Positive Predictive Value of 5.2%. The rate of positive serological tests for each Healthcare facility varied between 0% and 78%. Five percent of all facilities, belonging to Brescia, Bergamo and Cremona area, reported a positivity rate higher than 40% in HCWs. A second cluster (18% of all facilities), involving the same geographical area, reported a rate between 20% and 40%, whereas the remaining facilities (76%) of the region a rate <20%. Lessons Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs especially in a high infection prevalence setting. Key messages Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs. Infection prevention in HCW may benefit from a screening campaign especially in high prevalence settings.

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Monitoring Current-Season Spread of Potato virus Y in Potato Fields Using ELISA and Real-Time RT-PCR

Plant Disease ◽

10.1094/pdis-03-12-0283-re ◽

2013 ◽

Vol 97 (5) ◽

pp. 641-644 ◽

Cited By ~ 17

Author(s):

Manphool S. Fageria ◽

Mathuresh Singh ◽

Upeksha Nanayakkara ◽

Yvan Pelletier ◽

Xianzhou Nie ◽

...

Keyword(s):

Real Time ◽

Potato Virus ◽

Potato Virus Y ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Pcr Assay ◽

Current Season ◽

Seed Market ◽

Polymerase Chain ◽

Time Of Harvest

The current-season spread of Potato virus Y (PVY) was investigated in New Brunswick, Canada, in 11 potato fields planted with six different cultivars in 2009 and 2010. In all, 100 plants selected from each field were monitored for current-season PVY infections using enzyme-linked immunosorbent assay (ELISA) and real-time reverse-transcription polymerase chain reaction (RT-PCR) assay. Average PVY incidence in fields increased from 0.6% in 2009 and 2% in 2010 in the leaves to 20.3% in 2009 and 21.9% in 2010 in the tubers at the time of harvest. In individual fields, PVY incidence in tubers reached as high as 37% in 2009 and 39% in 2010 at the time of harvest. Real-time RT-PCR assay detected more samples with PVY from leaves than did ELISA. A higher number of positive samples was also detected with real-time RT-PCR from growing tubers compared with the leaves collected from the same plant at the same sampling time. PVY incidence determined from the growing tubers showed a significant positive correlation with the PVY incidence of tubers after harvest. Preharvest testing provides another option to growers to either top-kill the crop immediately to secure the seed market when the PVY incidence is low or leave the tubers to develop further for table or processing purposes when incidence of PVY is high.

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Polycistronic transcription of fused cassettes and identification of translation initiation signals in an unusual gene cassette array from Pseudomonas aeruginosa

F1000Research ◽

10.12688/f1000research.2-99.v2 ◽

2015 ◽

Vol 2 ◽

pp. 99

Author(s):

Érica L. Fonseca ◽

Ana Carolina Paulo Vicente

Keyword(s):

Real Time ◽

Northern Blot ◽

Gene Cassette ◽

Rt Pcr ◽

Recombination Site ◽

Gene Cassettes ◽

Polycistronic Transcription ◽

Polymerase Chain ◽

Fused Gene ◽

Gene Cassette Array

The gene cassettes found in class 1 integrons are generally promoterless units composed by an open reading frame (ORF), a short 5’ untranslated region (UTR) and a 3’ recombination site (attC). Fused gene cassettes are generated by partial or total loss of the attC from the first cassette in an array, creating, in some cases, a fusion with the ORF from the next cassette. These structures are rare and little is known about their mechanisms of mobilization and expression. The aim of this study was to evaluate the dynamic of mobilization and transcription of the gcu14-blaGES-1/aacA4 gene cassette array, which harbours a fused gene cassette represented by blaGES-1/aacA4. The cassette array was analyzed by Northern blot and real-time reverse transcription-polymerase chain reaction (RT-PCR) in order to assess the transcription mechanism of blaGES-1/aacA4 fused cassette. Also, inverse polymerase chain reactions (PCR) were performed to detect the free circular forms of gcu14, blaGES-1 and aacA4. The Northern blot and real time RT-PCR revealed a polycistronic transcription, in which the fused cassette blaGES-1/aacA4 is transcribed as a unique gene, while gcu14 (with a canonical attC recombination site) has a monocistronic transcription. The gcu14 cassette, closer to the weak configuration of cassette promoter (PcW), had a higher transcription level than blaGES-1/aacA4, indicating that the cassette position affects the transcript amounts. The presence of ORF-11 at attI1, immediately preceding gcu14, and of a Shine-Dalgarno sequence upstream blaGES-1/aacA4 composes a scenario for the occurrence of array translation. Inverse PCR generated amplicons corresponding to gcu14, gcu14-aacA4 and gcu14-blaGES-1/aacA4 free circular forms, but not to blaGES-1 and aacA4 alone, indicating that the GES-1 truncated attC is not substrate of integrase activity and that these genes are mobilized together as a unique cassette. This study was original in showing the transcription of fused cassettes and in correlating cassette position with transcription.

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Investigation of Different Commercially Available Real Time-Polymerase Chain Reaction Kits for SARS-CoV-2 Diagnosis

JOURNAL FOR CLINICAL AND DIAGNOSTIC RESEARCH ◽

10.7860/jcdr/2021/48726.14977 ◽

2021 ◽

Author(s):

Rajeev Kumar Jain ◽

Nagaraj Perumal ◽

Rakesh Shrivastava ◽

Kamlesh Kumar Ahirwar ◽

Jaya Lalwani ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Real Time ◽

Internal Control ◽

Housekeeping Genes ◽

Housekeeping Gene ◽

Specific Gene ◽

Rt Pcr ◽

Chain Reaction ◽

Gene Target ◽

Polymerase Chain

Introduction: The whole world is facing an ongoing global health emergency of COVID-19 disease caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Real-Time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) is a gold standard in the detection of SARS-CoV-2 infection. Presently, many single tube multiple gene target RT-PCR kits have been developed and are commercially available for Coronavirus Disease 2019 (COVID-19) diagnosis. Aim: To evaluate the performance of seven COVID-19 RT-PCR kits (DiagSure, Meril, VIRALDTECT II, TruPCR, Q-line, Allplex and TaqPath) which are commercially available for COVID-19 RT-PCR diagnosis. Materials and Methods: This observational study was conductedat the State Virology Laboratory (SVL), Gandhi Medical College, Bhopal, Madhya Pradesh, India. Seven commercially available kits have been evaluated on the basis of: (i) number of SARS-CoV-2 specific gene target; (ii) human housekeeping genes as internal control; (iii) RT-PCR run time; and (iv) kit performances to correctly detect SARS-CoV-2 positive and negative RNA samples. A total of 50 RNA samples (left over RNA) were included, master mix preparation, template addition and RT-PCR test has been performed according to kits literature. At the end of PCR run, mean and standard deviation of obtained cut-off of all kits were calculated using Microsoft Excel. Results: All seven RT-PCR kits performed satisfactory regarding the reproducibility and they could correctly identify 30 positive and 20 negative RNA samples. RNA samples (group C) having low viral loads with a high Cycle threshold (Ct) value (>30) were also detected by all these seven kits. Obtained Ct values of each group was in parallel range in comparison with the initial testing Ct values. Kits were found to be superior which contains primers and probes for three SARS-CoV-2 specific gene targets, have human housekeeping gene as internal control and taking less time to complete RT-PCR. Conclusion: All seven COVID-19 RT-PCR kits included in this study demonstrated satisfactory performance and can be used for the routine molecular diagnosis of COVID-19 disease.

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Sensitive SYBR Green—Real Time PCR for the Detection and Quantitation of Avian Rotavirus A

Veterinary Sciences ◽

10.3390/vetsci6010002 ◽

2018 ◽

Vol 6 (1) ◽

pp. 2 ◽

Cited By ~ 2

Author(s):

David De la Torre ◽

Claudete Astolfi-Ferreira ◽

Ruy Chacon ◽

Antonio Piantino Ferreira

Keyword(s):

Polymerase Chain Reaction ◽

Real Time ◽

Sybr Green ◽

Molecular Techniques ◽

Economic Losses ◽

Rt Pcr ◽

Chain Reaction ◽

Rotavirus A ◽

Avian Nephritis Virus ◽

Polymerase Chain

Avian rotavirus A (ARtV-A) is a virus that affects young birds, causing acute diarrhea and economic losses in the poultry industry worldwide. The techniques used for the diagnosis of ARtV-A include electron microscopy, isolation in cell culture, and serology, as well as molecular techniques, such as the reverse transcription-polymerase chain reaction (RT-PCR). The objective of this work was to standardize a real-time RT-polymerase chain reaction (RT-qPCR) using SYBR Green chemistry for the rapid detection and quantification of ARtV-A from bird tissues and materials fixed on FTA cards on the basis of the nucleotide sequence of segment 6 (S6), which codes for the structural VP6 protein of ARtV-A. The results show the efficient amplification of the proposed target, with a limit of detection (LoD) of one copy gene (CG) per microliter of cDNA and a limit of quantification (LoQ) of 10 CGs per microliter. The efficiency of the primers was determined to be 95.66% using a standard curve, with an R2 value of 0.999 and a slope of −3.43. The specificity was determined using samples coinfected with ARtV-A, the chicken parvovirus, the chicken astrovirus, and the avian nephritis virus as positive controls and commercially available vaccines of the infectious bronchitis virus, infectious bursa disease virus, avian reovirus and healthy organs as negative controls. This technique, which lacks nonspecific PCR products and dimers, demonstrated greater sensitivity and specificity than conventional RT-PCR, and it reduced the analysis time by more than 50%.

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Accuracy of real-time polymerase chain reaction to detect Schistosoma mansoni – infected individuals from an endemic area with low parasite loads

Parasitology ◽

10.1017/s003118202000089x ◽

2020 ◽

Vol 147 (10) ◽

pp. 1140-1148

Author(s):

Fernanda do Carmo Magalhães ◽

Samira Diniz Resende ◽

Carolina Senra ◽

Carlos Graeff-Teixeira ◽

Martin Johannes Enk ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Schistosoma Mansoni ◽

Real Time ◽

Diagnostic Methods ◽

Control Measures ◽

Rt Pcr ◽

Chain Reaction ◽

Cross Sectional ◽

Intestinal Schistosomiasis ◽

Polymerase Chain

AbstractDue to the efforts to control schistosomiasis transmission in tropical countries, a large proportion of individuals from endemic areas present low parasite loads, which hinders diagnosis of intestinal schistosomiasis by the Kato-Katz (KK) method. Therefore, the development of more sensitive diagnostic methods is essential for efficient control measures. The aim was to evaluate the accuracy of a real-time polymerase chain reaction (RT-PCR) to detect Schistosoma mansoni DNA in fecal samples of individuals with low parasite loads. A cross-sectional population-based study was conducted in a rural community (n = 257) in Brazil. POC-CCA® was performed in urine and feces were used for RT-PCR. In addition, fecal exams were completed by 18 KK slides, saline gradient and Helmintex techniques. The combined results of the three parasitological tests detected schistosome eggs in 118 participants (45.9%) and composed the consolidated reference standard (CRS). By RT-PCR, 117 out of 215 tested samples were positive, showing 91.4% sensitivity, 80.2% specificity and good concordance with the CRS (kappa = 0.71). RT-PCR identified 86.9% of the individuals eliminating less than 12 eggs/g of feces, demonstrating much better performance than POC-CCA® (50.8%). Our results showed that RT-PCR is a valuable alternative for the diagnosis of intestinal schistosomiasis in individuals with very low parasite loads.

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Establishment and evaluation of real-time PCR for West Nile virus detection

Chinese Journal of Agricultural Biotechnology ◽

10.1017/s1479236209002599 ◽

2009 ◽

Vol 6 (1) ◽

pp. 55-59 ◽

Cited By ~ 1

Author(s):

Shi Li-Jun ◽

Lu Mao-Min ◽

Li Gang ◽

Li Cheng-Yao ◽

Zhang Jin-Gang

Keyword(s):

West Nile Virus ◽

Real Time ◽

Virus Detection ◽

Rt Pcr ◽

Pcr Assay ◽

West Nile ◽

Capsid Protein Gene ◽

Specific Test ◽

Intercalating Dye ◽

Polymerase Chain

AbstractA rapid real-time polymerase chain reaction (RT-PCR) for detecting West Nile virus (WNV) was established. Primers were designed according to the sequence of the capsid protein gene of WNV by Primer Premier 5.0. In this way, an inexpensive assay using the intercalating dye SYBR Green I was developed and validated. The amplifying curve showed that this method could successfully amplify 102 copies/μl of the WNV gene, while reference to Japanese encephalitis virus (JEV) and blank control were all negative. Tenfold successive dilutions of positive WNV DNA were used to measure the sensitivity of RT-PCR. The assay system showed high reproducibility with coefficient of variation (CV) <2%. Thus the newly established RT-PCR assay was shown to be a rapid, sensitive and specific test for detecting WNV.

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