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Degarege A, Levecke B, Negash Y, Animut A, Erko B. Clinical sensitivity and time-to-result of a cascaded pooled testing approach for assessing the prevalence and intensity of Schistosoma haematobium infection. PLoS Negl Trop Dis 2024; 18:e0012435. [PMID: 39173069 PMCID: PMC11373869 DOI: 10.1371/journal.pntd.0012435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 09/04/2024] [Accepted: 08/05/2024] [Indexed: 08/24/2024] Open
Abstract
BACKGROUND This study compared the clinical sensitivity and the time-to-result of an individual testing (IT) and a cascaded pooled testing approach (CPT; a positive test result in a pooled sample triggers examination of smaller-sized pools or individual samples) for assessing the prevalence and the intensity of Schistosoma haematobium infection. We also compared the sensitivity of the CPT in detecting S. haematobium infection when deploying urine filtration microscopy (UFM) vs. urine reagent strips (URS), and testing 10 mL vs. 15 mL of urine. METHODOLOGY/PRINCIPAL FINDINGS Between October 2021 and April 2022, S. haematobium eggs were counted in urine samples collected from school-aged children living in the Afar and Gambella Regional States of Ethiopia. Urine samples were collected at baseline (n = 1,288), and one month after administration of praziquantel (n = 118). All urine samples were processed through both an IT and a CPT approach (pools of 5, 10, 20, and 40 individual samples), deploying UFM (10 mL) and URS (10 mL). In addition, 15 mL urine was processed through the CPT deploying UFM. At baseline, the prevalence of S. haematobium infection estimated when using UFM and deploying a CPT approach was significantly lower (17.3%) compared to an IT approach (31.5%). The clinical sensitivity of the CPT in detecting S. haematobium eggs was 51.7%. The sensitivity increased significantly as a function of increasing log transformed urine egg counts (UECs) of the individual samples (OR 2.71, 95%CI 1.63 - 4.52). The sensitivity was comparable when the amount of urine examined was 10 mL (51.7%) vs. 15 ml (50.8%), and when UFM was used for testing vs. URS (51.5%). The mean log UECs estimated following the CPT approach was lower compared to the estimate by the IT (p <0.001). UECs of the individual samples estimated using the IT and CPT approaches were moderately correlated (r = 0.59 when 10 mL and 15 mL urine was examined after pooling). CPT reduced the time needed for processing urine samples and testing for S. haematobium infection by 29% with UFM and by 27.7% with URS. CONCLUSIONS/SIGNIFICANCE CPT based on UFM and URS techniques may help to rapidly identify areas with higher prevalence of S. haematobium infection (hotspots) in a population. However, the performance of this approach in estimating the prevalence of infection may be compromised, particularly in endemic areas with low intensity infection.
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Affiliation(s)
- Abraham Degarege
- Department of Epidemiology, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Yohannes Negash
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Abebe Animut
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Berhanu Erko
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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Xiong W, Ding J, Zhang W, Liu A, Li Q. Nested Group Testing Procedure. COMMUNICATIONS IN MATHEMATICS AND STATISTICS 2022; 11:1-31. [PMID: 36213843 PMCID: PMC9525165 DOI: 10.1007/s40304-021-00269-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 06/27/2021] [Accepted: 10/13/2021] [Indexed: 06/16/2023]
Abstract
We investigated the false-negative, true-negative, false-positive, and true-positive predictive values from a general group testing procedure for a heterogeneous population. We show that its false (true)-negative predictive value of a specimen is larger (smaller), and the false (true)-positive predictive value is smaller (larger) than that from individual testing procedure, where the former is in aversion. Then we propose a nested group testing procedure, and show that it can keep the sterling characteristics and also improve the false-negative predictive values for a specimen, not larger than that from individual testing. These characteristics are studied from both theoretical and numerical points of view. The nested group testing procedure is better than individual testing on both false-positive and false-negative predictive values, while retains the efficiency as a basic characteristic of a group testing procedure. Applications to Dorfman's, Halving and Sterrett procedures are discussed. Results from extensive simulation studies and an application to malaria infection in microscopy-negative Malawian women exemplify the findings.
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Affiliation(s)
- Wenjun Xiong
- School of Mathematics and Statistics, Guangxi Normal University, Guilin, 541004 People’s Republic of China
| | - Juan Ding
- Department of Information and Computing Science, College of Sciences, Hohai University, Nanjing, 210098 People’s Republic of China
| | - Wei Zhang
- LSC, NCMIS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190 People’s Republic of China
| | - Aiyi Liu
- Biostatisics and Bioinformatics Branch, Eunice Kennedy Shriver National Institute of Child Health, Bethesda, 20817 USA
| | - Qizhai Li
- LSC, NCMIS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190 People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
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Phan T, Tran NYK, Gottlieb T, Siarakas S, McKew G. Evaluation of the influenza and respiratory syncytial virus (RSV) targets in the AusDiagnostics SARS-CoV-2, Influenza and RSV 8-well assay: sample pooling increases testing throughput. Pathology 2022; 54:466-471. [PMID: 35461715 PMCID: PMC9021007 DOI: 10.1016/j.pathol.2022.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 01/09/2022] [Accepted: 02/22/2022] [Indexed: 02/06/2023]
Abstract
During the COVID-19 pandemic, sample pooling has proven an effective strategy to overcome the limitations of reagent shortages and expand laboratory testing capacity. The inclusion of influenza and respiratory syncytial virus (RSV) in a multiplex tandem PCR platform with SARS-CoV-2 provides useful diagnostic and infection control information. This study aimed to evaluate the performance of the influenza and RSV targets in the AusDiagnostics SARS-CoV-2, Influenza and RSV 8-well assay, including the effect of pooling samples on target detection. RSV target detection in clinical samples was compared to the Cepheid Xpert Xpress Flu/RSV assay as a reference standard. Samples were then tested in pools of four and detection rates were compared. Owing to the unavailability of clinical samples for influenza, only the effect of sample pooling on simulated samples was evaluated for these targets. RSV was detected in neat clinical samples with a positive percent agreement (PPA) of 100% and negative percent agreement (NPA) of 99.5% compared to the reference standard, demonstrating 99.7% agreement. This study demonstrates that sample pooling by four increases the average Ct value by 2.24, 2.29, 2.20 and 1.91 cycles for the target's influenza A, influenza A typing, influenza B and RSV, respectively. The commercial AusDiagnostics SARS-CoV-2, Influenza and RSV 8-well assay was able to detect influenza and RSV at an intermediate concentration within the limit of detection of the assay. Further studies to explore the applicability of sample pooling at the lower limit of detection of the assay is needed. Nevertheless, sample pooling has shown to be a viable strategy to increase testing throughput and reduce reagent usage. In addition, the multiplexed platform targeting various respiratory viruses assists with public health and infection control responses, clinical care, and patient management.
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Affiliation(s)
- Thuy Phan
- Department of Microbiology and Infectious Disease, Concord Repatriation General Hospital, NSW Health Pathology, Concord, NSW, Australia
| | - Ngoc Yen Kim Tran
- Department of Microbiology and Infectious Disease, Concord Repatriation General Hospital, NSW Health Pathology, Concord, NSW, Australia.
| | - Thomas Gottlieb
- Department of Microbiology and Infectious Disease, Concord Repatriation General Hospital, NSW Health Pathology, Concord, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Concord, NSW, Australia
| | - Steven Siarakas
- Department of Microbiology and Infectious Disease, Concord Repatriation General Hospital, NSW Health Pathology, Concord, NSW, Australia
| | - Genevieve McKew
- Department of Microbiology and Infectious Disease, Concord Repatriation General Hospital, NSW Health Pathology, Concord, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Concord, NSW, Australia
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Daniel EA, Esakialraj L BH, S A, Muthuramalingam K, Karunaianantham R, Karunakaran LP, Nesakumar M, Selvachithiram M, Pattabiraman S, Natarajan S, Tripathy SP, Hanna LE. Pooled Testing Strategies for SARS-CoV-2 diagnosis: A comprehensive review. Diagn Microbiol Infect Dis 2021; 101:115432. [PMID: 34175613 PMCID: PMC8127528 DOI: 10.1016/j.diagmicrobio.2021.115432] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/09/2021] [Indexed: 12/23/2022]
Abstract
SARS-CoV-2 has surged across the globe causing the ongoing COVID-19 pandemic. Systematic testing to facilitate index case isolation and contact tracing is needed for efficient containment of viral spread. The major bottleneck in leveraging testing capacity has been the lack of diagnostic resources. Pooled testing is a potential approach that could reduce cost and usage of test kits. This method involves pooling individual samples and testing them 'en bloc'. Only if the pool tests positive, retesting of individual samples is performed. Upon reviewing recent articles on this strategy employed in various SARS-CoV-2 testing scenarios, we found substantial diversity emphasizing the requirement of a common protocol. In this article, we review various theoretically simulated and clinically validated pooled testing models and propose practical guidelines on applying this strategy for large scale screening. If implemented properly, the proposed approach could contribute to proper utilization of testing resources and flattening of infection curve.
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Affiliation(s)
- Evangeline Ann Daniel
- Department of HIV/AIDS, National Institute for Research in Tuberculosis, Chennai, India.
| | | | - Anbalagan S
- Department of HIV/AIDS, National Institute for Research in Tuberculosis, Chennai, India
| | | | | | | | - Manohar Nesakumar
- Department of HIV/AIDS, National Institute for Research in Tuberculosis, Chennai, India
| | | | | | - Sudhakar Natarajan
- Department of HIV/AIDS, National Institute for Research in Tuberculosis, Chennai, India
| | | | - Luke Elizabeth Hanna
- Department of HIV/AIDS, National Institute for Research in Tuberculosis, Chennai, India.
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Hou P, Tebbs JM, Wang D, McMahan CS, Bilder CR. Array testing for multiplex assays. Biostatistics 2021; 21:417-431. [PMID: 30371749 DOI: 10.1093/biostatistics/kxy058] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 08/31/2018] [Accepted: 09/09/2018] [Indexed: 11/13/2022] Open
Abstract
Group testing involves pooling individual specimens (e.g., blood, urine, swabs, etc.) and testing the pools for the presence of disease. When the proportion of diseased individuals is small, group testing can greatly reduce the number of tests needed to screen a population. Statistical research in group testing has traditionally focused on applications for a single disease. However, blood service organizations and large-scale disease surveillance programs are increasingly moving towards the use of multiplex assays, which measure multiple disease biomarkers at once. Tebbs and others (2013, Two-stage hierarchical group testing for multiple infections with application to the Infertility Prevention Project. Biometrics69, 1064-1073) and Hou and others (2017, Hierarchical group testing for multiple infections. Biometrics73, 656-665) were the first to examine hierarchical group testing case identification procedures for multiple diseases. In this article, we propose new non-hierarchical procedures which utilize two-dimensional arrays. We derive closed-form expressions for the expected number of tests per individual and classification accuracy probabilities and show that array testing can be more efficient than hierarchical procedures when screening individuals for multiple diseases at once. We illustrate the potential of using array testing in the detection of chlamydia and gonorrhea for a statewide screening program in Iowa. Finally, we describe an R/Shiny application that will help practitioners identify the best multiple-disease case identification algorithm.
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Affiliation(s)
- Peijie Hou
- Statistical and Quantitative Sciences, Takeda Pharmaceutical Inc., 300 Massachusetts Avenue, Cambridge, MA, USA
| | - Joshua M Tebbs
- Department of Statistics, University of South Carolina, 1523 Greene St, Columbia, SC, USA
| | - Dewei Wang
- Department of Statistics, University of South Carolina, 1523 Greene St, Columbia, SC, USA
| | - Christopher S McMahan
- School of Mathematical and Statistical Sciences, Clemson University, O-110 Martin Hall, Clemson, SC, USA
| | - Christopher R Bilder
- Department of Statistics, University of Nebraska-Lincoln, 340 Hardin Hall North, Lincoln, NE, USA
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Shlonsky Y, Smair NS, Mubariki R, Bamberger E, Hemo M, Cohen S, Riskin A, Srugo I, Bader D, Golan-Shany O. Pooled saliva CMV DNA detection: A viable laboratory technique for universal CMV screening of healthy newborns. J Clin Virol 2021; 138:104798. [PMID: 33770655 DOI: 10.1016/j.jcv.2021.104798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 02/02/2021] [Accepted: 03/14/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND Most infants with congenital cytomegalovirus (cCMV) have no overt manifestations at birth, yet may later develop CMV-related sensorineural hearing loss (SNHL). With targeted screening, many asymptomatic neonates are missed and lose the opportunity for timely anti-viral treatment to ameliorate SNHL. Saliva is the preferred screening specimen given its ease of collection. OBJECTIVES Assess a pooled saliva CMV DNA detection technique for cCMV screening of healthy full-term neonates. STUDY DESIGN We conducted a prospective laboratory CMV PCR screening study in a secondary hospital from March-June 2019. Saliva specimens were obtained from 1000 newborns two-four hours after birth. Specimens were analyzed for CMV DNA with a real-time PCR platform (Altona) in pools of 10 and individually (40 μL and 400 μL, respectively). Neonates with positive saliva CMV DNA detection required urine CMV PCR testing to confirm cCMV diagnosis. RESULTS From the 1000 saliva samples, there were 6 urine-confirmed cCMV cases, yielding a prevalence rate of 0.6 %. The specificity was high for both pooled and individual saliva sampling (99.9 % and 98.1 %, respectively). The positive predictive value of the pooled sample was 85.7 %, compared to 24.0 % for a single saliva sample. CONCLUSIONS Pooling saliva of healthy newborns appears to be a reliable method to identify asymptomatic cCMV infection when positive results are confirmed by urine CMV DNA. Pooling in sizes appropriate to the cCMV prevalence rate may improve the laboratory workflow and decrease costs. Further studies should evaluate the clinical implications of this widespread cCMV pooled screening technique.
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Affiliation(s)
| | | | | | | | - Miri Hemo
- Bnai Zion Medical Center, Haifa, Israel
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Acquisition of multidrug-resistant bacteria and encoding genes among French pilgrims during the 2017 and 2018 Hajj. Eur J Clin Microbiol Infect Dis 2021; 40:1199-1207. [DOI: 10.1007/s10096-020-04122-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 12/02/2020] [Indexed: 12/23/2022]
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8
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Schulte PA, Weissman DN, Luckhaupt SE, de Perio MA, Beezhold D, Piacentino JD, Radonovich LJ, Hearl FJ, Howard J. Considerations for Pooled Testing of Employees for SARS-CoV-2. J Occup Environ Med 2021; 63:1-9. [PMID: 33378322 PMCID: PMC7773162 DOI: 10.1097/jom.0000000000002049] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To identify important background information on pooled tested of employees that employers workers, and health authorities should consider. METHODS This paper is a commentary based on the review by the authors of pertinent literature generally from preprints in medrixiv.org prior to August 2020. RESULTS/CONCLUSIONS Pooled testing may be particularly useful to employers in communities with low prevalence of COVID-19. It can be used to reduce the number of tests and associated financial costs. For effective and efficient pooled testing employers should consider it as part of a broader, more comprehensive workplace COVID-19 prevention and control program. Pooled testing of asymptomatic employees can prevent transmission of SARS-CoV-2 and help assure employers and customers that employees are not infectious.
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Affiliation(s)
- Paul A Schulte
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1090 Tusculum Avenue, Cincinnati, Ohio (Dr Schulte); National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, West Virginia (Dr Weissman, Dr Beezhold, Dr Radonovich); National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 5555 Ridge Avenue, Cincinnati, Ohio (Dr Luckhaupt, Dr de Perio); National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 395 E Street SW, Washington, DC 20024 (Dr Piacentino, Hearl, Dr Howard)
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Dao TL, Hoang VT, Magmoun A, Ly TDA, Baron SA, Hadjadj L, Canard N, Drali T, Gouriet F, Raoult D, Parola P, Marty P, Rolain JM, Gautret P. Acquisition of multidrug-resistant bacteria and colistin resistance genes in French medical students on internships abroad. Travel Med Infect Dis 2020; 39:101940. [PMID: 33248262 DOI: 10.1016/j.tmaid.2020.101940] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/31/2020] [Accepted: 11/22/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND Acquisition of multidrug resistant bacteria (MDR) and colistin resistance genes by international travellers has been demonstrated. Studies conducted in medical students during internships abroad are scant. METHODS Nasopharyngeal, rectal, and vaginal swabs samples were collected from 382 French medical students before and after travel to investigate the acquisition of MDR bacteria. The bacterial diversity in the samples was assessed by culture on selective media. We also genetically characterised the isolates of MDR bacteria including Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E), methicillin-resistant Staphylococcus aureus (MRSA), and Carbapenemase-producing Enterobacteriacae (CPE) using the real-time polymerase chain reaction method. The samples were collected from 293 students and were investigated for mcr colistin-resistance genes using RT-PCR directly on the samples, followed by conventional PCR and sequencing. RESULTS A proportion of 29.3% (112/382) of the participants had acquired ESBL-E and 2.6% (10/382) had acquired CPE. The most common species and ESBL-E encoding gene were Escherichia coli (125/127 isolates, 98.4%) and blaCTX-M-A (121/127, 95.3%), respectively. A proportion of 6.8% (20/293) of the participants had acquired mcr-1 genes, followed by mcr-3 (1/293, 0.3%) and mcr-8 (1/293, 0.3%). We found that taking part in humanitarian missions to orphanages (aRR = 2.01, p < 0.0001), being in contact with children during travel (aRR = 1.78, p = 0.006), the primary destination of travel being Vietnam (aRR = 2.15, p < 0.0001) and north India (aRR = 2.41, p = 0.001), using antibiotics during travel (aRR = 1.77, p = 0.01), and studying in 2018 (aRR = 1.55, p = 0.03) were associated with the acquisition of ESBL-E. When the primary destination of travel was Vietnam (aRR = 2.74, p < 0.0001) and the year of study was 2018 (aRR = 1.93, p < 0.002), this was associated with acquisition of colistin resistance genes. CONCLUSION Medical students are at a potential risk of acquiring ESBL-E, CPE and colistin resistance genes. A number of risk factors have been identified, which may be used to develop targeted preventive measures.
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Affiliation(s)
- Thi Loi Dao
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France; Thai Binh University of Medicine and Pharmacy, Thai Binh, Viet Nam
| | - Van Thuan Hoang
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France; Thai Binh University of Medicine and Pharmacy, Thai Binh, Viet Nam
| | - Amal Magmoun
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France
| | - Tran Duc Anh Ly
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France
| | - Sophie Alexandra Baron
- IHU-Méditerranée Infection, Marseille, France; Aix Marseille Univ, IRD, AP-HM, MEPHI, Marseille, France
| | - Linda Hadjadj
- IHU-Méditerranée Infection, Marseille, France; Aix Marseille Univ, IRD, AP-HM, MEPHI, Marseille, France
| | - Naomie Canard
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France
| | - Tassadit Drali
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France
| | - Frédérique Gouriet
- IHU-Méditerranée Infection, Marseille, France; Aix Marseille Univ, IRD, AP-HM, MEPHI, Marseille, France
| | - Didier Raoult
- IHU-Méditerranée Infection, Marseille, France; Aix Marseille Univ, IRD, AP-HM, MEPHI, Marseille, France
| | - Philippe Parola
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France
| | - Pierre Marty
- Université Côte D'Azur, Inserm, C3M, Nice Cedex 3, France; Parasitologie-Mycologie, Centre Hospitalier Universitaire L'Archet, Nice Cedex 3, France
| | - Jean-Marc Rolain
- IHU-Méditerranée Infection, Marseille, France; Aix Marseille Univ, IRD, AP-HM, MEPHI, Marseille, France
| | - Philippe Gautret
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France.
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Abstract
Background: Liberal PCR testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is key to contain the coronavirus disease 2019 (COVID-19) pandemic. Combined multi-sample testing in pools instead of single tests might enhance laboratory capacity and reduce costs, especially in low- and middle-income countries. Objective: The purpose of our study was to assess the value of a simple questionnaire to guide and further improve pooling strategies for SARS-CoV-2 laboratory testing. Methods: Pharyngeal swabs for SARS-CoV-2 testing were obtained from healthcare and police staff, hospital inpatients, and nursing home residents in the southwestern part of Germany. We designed a simple questionnaire, which included questions pertaining to a suggestive clinical symptomatology, recent travel history, and contact with confirmed cases to stratify an individual’s pre-test probability of having contracted COVID-19. The questionnaire was adapted repeatedly in face of the unfolding pandemic in response to the evolving epidemiology and observed clinical symptomatology. Based on the response patterns, samples were either tested individually or in multi-sample pools. We compared the pool positivity rate and the number of total PCR tests required to obtain individual results between this questionnaire-based pooling strategy and randomly assembled pools. Findings: Between March 11 and July 5, 2020, we processed 25,978 samples using random pooling (n = 6,012; 23.1%) or questionnaire-based pooling (n = 19,966; 76.9%). The overall prevalence of SARS-CoV-2 was 0.9% (n = 238). Pool positivity (14.6% vs. 1.2%) and individual SARS-CoV-2 prevalence (3.4% vs. 0.1%) were higher in the random pooling group than in the questionnaire group. The average number of PCR tests needed to obtain the individual result for one participant was 0.27 tests in the random pooling group, as compared to 0.09 in the questionnaire-based pooling group, leading to a laboratory capacity increase of 73% and 91%, respectively, as compared to single PCR testing. Conclusions: Strategies that combine pool testing with a questionnaire-based risk stratification can increase laboratory testing capacities for COVID-19 and might be important tools, particularly in resource-constrained settings.
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11
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Furstenau TN, Cocking JH, Hepp CM, Fofanov VY. Sample pooling methods for efficient pathogen screening: Practical implications. PLoS One 2020; 15:e0236849. [PMID: 33175841 PMCID: PMC7657563 DOI: 10.1371/journal.pone.0236849] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 10/14/2020] [Indexed: 01/06/2023] Open
Abstract
Due to the large number of negative tests, individually screening large populations for rare pathogens can be wasteful and expensive. Sample pooling methods improve the efficiency of large-scale pathogen screening campaigns by reducing the number of tests and reagents required to accurately categorize positive and negative individuals. Such methods rely on group testing theory which mainly focuses on minimizing the total number of tests; however, many other practical concerns and tradeoffs must be considered when choosing an appropriate method for a given set of circumstances. Here we use computational simulations to determine how several theoretical approaches compare in terms of (a) the number of tests, to minimize costs and save reagents, (b) the number of sequential steps, to reduce the time it takes to complete the assay, (c) the number of samples per pool, to avoid the limits of detection, (d) simplicity, to reduce the risk of human error, and (e) robustness, to poor estimates of the number of positive samples. We found that established methods often perform very well in one area but very poorly in others. Therefore, we introduce and validate a new method which performs fairly well across each of the above criteria making it a good general use approach.
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Affiliation(s)
- Tara N. Furstenau
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jill H. Cocking
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, United States of America
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Crystal M. Hepp
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, United States of America
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Viacheslav Y. Fofanov
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, United States of America
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
- * E-mail:
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12
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Borillo GA, Kagan RM, Baumann RE, Fainstein BM, Umaru L, Li HR, Kaufman HW, Clarke NJ, Marlowe EM. Pooling of Upper Respiratory Specimens Using a SARS-CoV-2 Real-time RT-PCR Assay Authorized for Emergency Use in Low-Prevalence Populations for High-Throughput Testing. Open Forum Infect Dis 2020; 7:ofaa466. [PMID: 33204756 PMCID: PMC7543567 DOI: 10.1093/ofid/ofaa466] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/02/2022] Open
Abstract
Background Nucleic acid amplification testing is a critical tool for addressing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Specimen pooling can increase throughput and conserve testing resources but requires validation to ensure that reduced sensitivity does not increase the false-negative rate. We evaluated the performance of a real-time reverse transcription polymerase chain reaction (RT-PCR) test authorized by the US Food and Drug Administration (FDA) for emergency use for pooled testing of upper respiratory specimens. Methods Positive specimens were selected from 3 prevalence groups, 1%–3%, >3%–6%, and >6%–10%. Positive percent agreement (PPA) was assessed by pooling single-positive specimens with 3 negative specimens; performance was assessed using Passing-Bablok regression. Additionally, we assessed the distributions of RT-PCR cycle threshold (Ct) values for 3091 positive specimens. Results PPA was 100% for the 101 pooled specimens. There was a linear relationship between Ct values for pooled and single-tested specimens (r = 0.96–0.99; slope ≈ 1). The mean pooled Ct shifts at 40 cycles were 2.38 and 1.90, respectively, for the N1 and N3 targets. The median Cts for 3091 positive specimens were 25.9 (N1) and 24.7 (N3). The percentage of positive specimens with Cts between 40 and the shifted Ct was 1.42% (N1) and 0.0% (N3). Conclusions Pooled and individual testing of specimens positive for SARS-CoV-2 demonstrated 100% agreement, which demonstrates the viability of pooled specimens for SARS-COV-2 testing using a dual-target RT-PCR system. Pooled specimen testing can help increase testing capacity for SARS-CoV-2 with a low risk of false-negative results.
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Affiliation(s)
| | - Ron M Kagan
- Quest Diagnostics Infectious Disease, San Juan Capistrano, California, USA
| | - Russell E Baumann
- Quest Diagnostics Infectious Disease, San Juan Capistrano, California, USA
| | | | - Lamela Umaru
- Quest Diagnostics Infectious Disease, San Juan Capistrano, California, USA
| | - Hai-Rong Li
- Quest Diagnostics Nichols Institute, San Juan Capistrano, California, USA
| | - Harvey W Kaufman
- Quest Diagnostics Information Ventures, Needham, Massachusetts, USA
| | - Nigel J Clarke
- Quest Diagnostics Nichols Institute, San Juan Capistrano, California, USA
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13
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Deckert A, Bärnighausen T, Kyei NN. Simulation of pooled-sample analysis strategies for COVID-19 mass testing. Bull World Health Organ 2020; 98:590-598. [PMID: 33012859 PMCID: PMC7463190 DOI: 10.2471/blt.20.257188] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/19/2020] [Accepted: 05/21/2020] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVE To evaluate two pooled-sample analysis strategies (a routine high-throughput approach and a novel context-sensitive approach) for mass testing during the coronavirus disease 2019 (COVID-19) pandemic, with an emphasis on the number of tests required to screen a population. METHODS We used Monte Carlo simulations to compare the two testing strategies for different infection prevalences and pooled group sizes. With the routine high-throughput approach, heterogeneous sample pools are formed randomly for polymerase chain reaction (PCR) analysis. With the novel context-sensitive approach, PCR analysis is performed on pooled samples from homogeneous groups of similar people that have been purposively formed in the field. In both approaches, all samples contributing to pools that tested positive are subsequently analysed individually. FINDINGS Both pooled-sample strategies would save substantial resources compared to individual analysis during surge testing and enhanced epidemic surveillance. The context-sensitive approach offers the greatest savings: for instance, 58-89% fewer tests would be required for a pooled group size of 3 to 25 samples in a population of 150 000 with an infection prevalence of 1% or 5%. Correspondingly, the routine high-throughput strategy would require 24-80% fewer tests than individual testing. CONCLUSION Pooled-sample PCR screening could save resources during COVID-19 mass testing. In particular, the novel context-sensitive approach, which uses pooled samples from homogeneous population groups, could substantially reduce the number of tests required to screen a population. Pooled-sample approaches could help countries sustain population screening over extended periods of time and thereby help contain foreseeable second-wave outbreaks.
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Affiliation(s)
- Andreas Deckert
- Heidelberg Institute of Global Health, Heidelberg University, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Till Bärnighausen
- Heidelberg Institute of Global Health, Heidelberg University, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Nicholas Na Kyei
- Heidelberg Institute of Global Health, Heidelberg University, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
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14
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Implementation of Antibody Rapid Diagnostic Testing versus Real-Time Reverse Transcription-PCR Sample Pooling in the Screening of COVID-19: a Case of Different Testing Strategies in Africa. mSphere 2020; 5:5/4/e00524-20. [PMID: 32727861 PMCID: PMC7392544 DOI: 10.1128/msphere.00524-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Coronavirus disease 2019 (COVID-19) has wreaked havoc across the globe; although the number of cases in Africa remains lower than in other regions, it is on a gradual upward trajectory. To date, COVID-19 cases have been reported in 54 out of 55 African countries. However, due to limited severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) real-time reverse transcription-PCR (rRT-PCR) testing capacity and scarcity of testing reagents, it is probable that the total number of cases could far exceed published statistics. In this viewpoint, using Ghana, Malawi, South Africa, and Zimbabwe as examples of countries that have implemented different testing strategies, we argue that the implementation of sample pooling for rRT-PCR over antibody rapid diagnostic testing could have a greater impact in assessing disease burden. Sample pooling offers huge advantages compared to single test rRT-PCR, as it reduces diagnostic costs, personnel time, burnout, and analytical run times. Africa is already strained in terms of testing resources for COVID-19; hence, cheaper alternative ways need to be implemented to conserve resources, maximize mass testing, and reduce transmission in the wider population.
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15
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Pouwels KB, Roope LSJ, Barnett A, Hunter DJ, Nolan TM, Clarke PM. Group Testing for SARS-CoV-2: Forward to the Past? PHARMACOECONOMICS - OPEN 2020; 4:207-210. [PMID: 32347512 PMCID: PMC7187661 DOI: 10.1007/s41669-020-00217-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Koen B Pouwels
- Health Economics Research Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Laurence S J Roope
- Health Economics Research Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Adrian Barnett
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, QLD, Australia
| | - David J Hunter
- Translational Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Terry M Nolan
- The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Philip M Clarke
- Health Economics Research Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
- Centre for Health Policy, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, Australia.
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16
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Lin J, Wang D, Zheng Q. Regression analysis and variable selection for two-stage multiple-infection group testing data. Stat Med 2019; 38:4519-4533. [PMID: 31297869 DOI: 10.1002/sim.8311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 03/03/2019] [Accepted: 06/14/2019] [Indexed: 12/17/2022]
Abstract
Group testing, as a cost-effective strategy, has been widely used to perform large-scale screening for rare infections. Recently, the use of multiplex assays has transformed the goal of group testing from detecting a single disease to diagnosing multiple infections simultaneously. Existing research on multiple-infection group testing data either exclude individual covariate information or ignore possible retests on suspicious individuals. To incorporate both, we propose a new regression model. This new model allows us to perform a regression analysis for each infection using multiple-infection group testing data. Furthermore, we introduce an efficient variable selection method to reveal truly relevant risk factors for each disease. Our methodology also allows for the estimation of the assay sensitivity and specificity when they are unknown. We examine the finite sample performance of our method through extensive simulation studies and apply it to a chlamydia and gonorrhea screening data set to illustrate its practical usefulness.
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Affiliation(s)
- Juexin Lin
- Department of Statistics, University of South Carolina, South Carolina
| | - Dewei Wang
- Department of Statistics, University of South Carolina, South Carolina
| | - Qi Zheng
- Department of Bioinformatics and Biostatistics, University of Louisville, Kentucky
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17
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Ly TDA, Hadjadj L, Hoang VT, Louni M, Dao TL, Badiaga S, Tissot-Dupont H, Raoult D, Rolain JM, Gautret P. Low prevalence of resistance genes in sheltered homeless population in Marseille, France, 2014-2018. Infect Drug Resist 2019; 12:1139-1151. [PMID: 31123411 PMCID: PMC6511248 DOI: 10.2147/idr.s202048] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 03/07/2019] [Indexed: 12/23/2022] Open
Abstract
Objectives: The present study has explored the prevalence and potential factors contributing to the presence of nasal/pharyngeal resistant genes in homeless people. Methods: During the winters 2014-2018, we enrolled sheltered homeless adults and controls and collected nasal/pharyngeal samples. Sixteen antibiotic resistance genes (ARGs), including genes encoding for beta-lactamases and colistin-resistance genes, were searched by real-time polymerase chain reaction (qPCR) performed directly on respiratory samples and followed by conventional PCR and sequencing. Results: Over a 5-year period, using qPCR, we identified in homeless group (n=715) the presence of bla TEM (396/710, 54.7%), blaSHV (27/708, 3.6%), bla OXA-23 (1/708, 0.1%), while other genes including colistin-resistance genes (mcr-1 to mcr-5) were absent. We found a significantly higher proportion of ARG carriage among controls (74.1%) compared to homeless population (57.1%), p=0.038. Tobacco smoking (OR=4.72, p<0.0001) and respiratory clinical signs (OR=4.03, p=0.002) were most prevalent in homeless people, while vaccination against influenza (OR=0.31, p=0.016) was lower compared to controls. Among homeless people, type of housing (shelter A versus B, OR=1.59, p=0.006) and smoking tobacco (smoker versus non-smoker, OR=0.55, p=0.001) were independent factors associated with ARG carriage. By sequencing, we obtained a high diversity of bla TEM and blaSHV in both populations. Conclusion: The lower risk for ARGs in the homeless population could be explained by limited access to health care and subsequently reduced exposure to antibiotics.
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Affiliation(s)
- Tran Duc Anh Ly
- IRD, AP-HM, SSA, VITROME, Aix Marseille Univ., Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Linda Hadjadj
- IHU-Méditerranée Infection, Marseille, France.,MEPHI, Aix Marseille Univ., Marseille, France
| | - Van Thuan Hoang
- IRD, AP-HM, SSA, VITROME, Aix Marseille Univ., Marseille, France.,IHU-Méditerranée Infection, Marseille, France.,Family Medicine Department, Thai Binh University of Medicine and Pharmacy, Thành Phố Thái Bình, Vietnam
| | - Meriem Louni
- IRD, AP-HM, SSA, VITROME, Aix Marseille Univ., Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Thi Loi Dao
- IRD, AP-HM, SSA, VITROME, Aix Marseille Univ., Marseille, France.,IHU-Méditerranée Infection, Marseille, France.,Pneumology Department, Thai Binh University of Medicine and Pharmacy, Thành Phố Thái Bình, Vietnam
| | - Sekene Badiaga
- IHU-Méditerranée Infection, Marseille, France.,Emergency Department, North Hospital, AP-HM, Marseille, France
| | - Herve Tissot-Dupont
- IHU-Méditerranée Infection, Marseille, France.,MEPHI, Aix Marseille Univ., Marseille, France
| | - Didier Raoult
- IHU-Méditerranée Infection, Marseille, France.,MEPHI, Aix Marseille Univ., Marseille, France
| | - Jean-Marc Rolain
- IHU-Méditerranée Infection, Marseille, France.,MEPHI, Aix Marseille Univ., Marseille, France
| | - Philippe Gautret
- IRD, AP-HM, SSA, VITROME, Aix Marseille Univ., Marseille, France.,IHU-Méditerranée Infection, Marseille, France
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18
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Wang D, McMahan CS, Tebbs JM, Bilder CR. Group testing case identification with biomarker information. Comput Stat Data Anal 2018; 122:156-166. [PMID: 29977101 DOI: 10.1016/j.csda.2018.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Screening procedures for infectious diseases, such as HIV, often involve pooling individual specimens together and testing the pools. For diseases with low prevalence, group testing (or pooled testing) can be used to classify individuals as diseased or not while providing considerable cost savings when compared to testing specimens individually. The pooling literature is replete with group testing case identification algorithms including Dorfman testing, higher-stage hierarchical procedures, and array testing. Although these algorithms are usually evaluated on the basis of the expected number of tests and classification accuracy, most evaluations in the literature do not account for the continuous nature of the testing responses and thus invoke potentially restrictive assumptions to characterize an algorithm's performance. Commonly used case identification algorithms in group testing are considered and are evaluated by taking a different approach. Instead of treating testing responses as binary random variables (i.e., diseased/not), evaluations are made by exploiting an assay's underlying continuous biomarker distributions for positive and negative individuals. In doing so, a general framework to describe the operating characteristics of group testing case identification algorithms is provided when these distributions are known. The methodology is illustrated using two HIV testing examples taken from the pooling literature.
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Affiliation(s)
- Dewei Wang
- Department of Statistics, University of South Carolina, Columbia, SC 29208, USA
| | | | - Joshua M Tebbs
- Department of Statistics, University of South Carolina, Columbia, SC 29208, USA
| | - Christopher R Bilder
- Department of Statistics, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
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19
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Mester P, Witte AK, Robben C, Streit E, Fister S, Schoder D, Rossmanith P. Optimization and evaluation of the qPCR-based pooling strategy DEP-pooling in dairy production for the detection of Listeria monocytogenes. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.06.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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20
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Pyo H, Lee CY, Kim D, Kim G, Lee S, Yun WS. Electrical Detection of Pneumococcus through the Nanoparticle Decoration Method. SENSORS 2017; 17:s17092012. [PMID: 28869504 PMCID: PMC5621115 DOI: 10.3390/s17092012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/19/2017] [Accepted: 08/31/2017] [Indexed: 11/21/2022]
Abstract
A simple method of nanoparticle decoration can be used in the detection of pneumococcus. After the pneumococcal bacteria were captured by an antibody (pneumococcal C-polysaccharide (PnC) antibody) between the interdigitated electrodes, the gold nanoparticles conjugated with the PnC antibodies were let to bind onto an outer membrane of the bacteria. Upon successfully dense decoration, the bacteria surface will become conductive owing to the metal nanoparticles, and a distinctive conductance change between the electrodes can be observed. Since this success ratio, or the probability of the conductance change, reflects the concentration of the analyte, a number of repeated measurements can be used in the quantification of the bacteria. In this way, we have successfully detected S. pneumoniae in the range of 10–108 CFU/mL. The limit of detection in this work is lower than that in the commercial detection kit. We hope that the nanoparticle decoration method will play a role in the facile detection of various bacteria.
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Affiliation(s)
- Hannah Pyo
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 440-746, Korea.
| | - Cho Yeon Lee
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 440-746, Korea.
| | - Daehee Kim
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 440-746, Korea.
| | - Gyuhee Kim
- Department of Biological Sciences, Sungkyunkwan University (SKKU), Suwon 440-746, Korea.
| | - Sangho Lee
- Department of Biological Sciences, Sungkyunkwan University (SKKU), Suwon 440-746, Korea.
| | - Wan Soo Yun
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 440-746, Korea.
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21
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Warasi MS, McMahan CS, Tebbs JM, Bilder CR. Group testing regression models with dilution submodels. Stat Med 2017; 36:4860-4872. [PMID: 28856774 DOI: 10.1002/sim.7455] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/27/2017] [Accepted: 08/11/2017] [Indexed: 12/21/2022]
Abstract
Group testing, where specimens are tested initially in pools, is widely used to screen individuals for sexually transmitted diseases. However, a common problem encountered in practice is that group testing can increase the number of false negative test results. This occurs primarily when positive individual specimens within a pool are diluted by negative ones, resulting in positive pools testing negatively. If the goal is to estimate a population-level regression model relating individual disease status to observed covariates, severe bias can result if an adjustment for dilution is not made. Recognizing this as a critical issue, recent binary regression approaches in group testing have utilized continuous biomarker information to acknowledge the effect of dilution. In this paper, we have the same overall goal but take a different approach. We augment existing group testing regression models (that assume no dilution) with a parametric dilution submodel for pool-level sensitivity and estimate all parameters using maximum likelihood. An advantage of our approach is that it does not rely on external biomarker test data, which may not be available in surveillance studies. Furthermore, unlike previous approaches, our framework allows one to formally test whether dilution is present based on the observed group testing data. We use simulation to illustrate the performance of our estimation and inference methods, and we apply these methods to 2 infectious disease data sets.
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Affiliation(s)
- Md S Warasi
- Department of Mathematics and Statistics, Radford University, Radford, VA 24142, USA
| | | | - Joshua M Tebbs
- Department of Statistics, University of South Carolina, Columbia, SC 29208, USA
| | - Christopher R Bilder
- Department of Statistics, University of Nebraska-Lincoln, Lincoln, NE 68583, NE, USA
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