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De Vitis E, Ricci S, Nieddu F, Moriondo M, Cortimiglia M, Casini A, Lodi L, Indolfi G, Azzari C. Real-time polymerase chain reaction on filter paper spotted samples: a gateway to molecular diagnosis of invasive bacterial diseases for rural areas in low-income countries. Trans R Soc Trop Med Hyg 2021; 116:233-241. [PMID: 34328186 DOI: 10.1093/trstmh/trab107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 12/25/2020] [Accepted: 07/14/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Bacterial culture is the gold standard for the diagnosis of invasive bacterial diseases (IBDs) but molecular methods are more specific and sensitive. Fresh liquid samples (FLSs) show patent limitations for shipping and storage. We aimed to evaluate the sensitivity and specificity of real-time polymerase chain reaction (PCR) performed on dried sample spots (DSSs) obtained from different biological fluids compared with real-time PCR or culture performed on FLSs. METHODS FLSs positive for Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, Bordetella pertussis and/or Pseudomonas aeruginosa were spotted on filter paper. Real-time PCR was performed on both FLSs and DSSs and results were compared. The stability of the DSS results over time was evaluated. RESULTS Real-time PCR performed on 114 DSSs showed a specificity of 99.1% and a sensitivity of 91.2% for IBD diagnosis. A positive correlation was found between FLS cycle threshold (Ct) and DSS Ct (r=0.84; r2=0.71) with the Pearson statistical test and Bland-Altman analysis showing that 95% of the specimens were within agreeable limits. Although we observed a trend towards signal reduction over time in the DSSs, there was no statistical evidence of an increase in Ct values. Real-time PCR on DSSs was 2.2 times more sensitive than culture. CONCLUSIONS Real-time PCR applied to DSSs may be a useful approach in different situations, such as IBD diagnosis, both for rural areas of low-income countries and family practitioners in various settings.
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Affiliation(s)
- Elisa De Vitis
- Department of Health Sciences, University of Florence and Meyer Children's University Hospital, Florence, Italy
| | - Silvia Ricci
- Department of Health Sciences, University of Florence and Meyer Children's University Hospital, Florence, Italy
| | - Francesco Nieddu
- Department of Health Sciences, University of Florence and Meyer Children's University Hospital, Florence, Italy
| | - Maria Moriondo
- Department of Health Sciences, University of Florence and Meyer Children's University Hospital, Florence, Italy
| | - Martina Cortimiglia
- Department of Health Sciences, University of Florence and Meyer Children's University Hospital, Florence, Italy
| | - Arianna Casini
- Department of Health Sciences, University of Florence and Meyer Children's University Hospital, Florence, Italy
| | - Lorenzo Lodi
- Department of Health Sciences, University of Florence and Meyer Children's University Hospital, Florence, Italy
| | - Giuseppe Indolfi
- Department of Paediatrics, Meyer Children's University Hospital, Florence, Italy
| | - Chiara Azzari
- Department of Health Sciences, University of Florence and Meyer Children's University Hospital, Florence, Italy
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Amarnath SK, Joshi S, Abhyankar MN, Adhikary R, Beena HB, Chugh TD, Gandhi KD, Hittinahalli V, Indumathi VA, Rajavari M, Muralidharan S, Rao SS, Roy I, Saini N. Cross-country transport and isolation and identification of Streptococcus pneumoniae by use of alternate sources of blood supplemented media among laboratories in India. Indian J Med Microbiol 2019; 37:363-369. [PMID: 32003334 DOI: 10.4103/ijmm.ijmm_19_82] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background The isolation of S. pneumoniae (Sp) depends on specimen integrity / transport, media and expertise. The non-availability of sheep blood agar poses a challenge in identification of colonial morphology and identification in India. Methods Laboratories processed swabs containing either pure Sp or Sp in mixed cultures with a second (confounding) bacterium shipped across the country in cold conditions. Duplicate set of swabs was shipped back to the central laboratory to assess the impact of shipping on culture viability. The identical swab was cultured on sheep, human blood and one additional agar plate used in the laboratory. Results 46/60(77%) of cultures containing only Sp were correctly identified. In specimens where Sp was present in mixed culture, the proportion of isolates in which Sp was correctly identified varied, with most variability attributed to the particular confounding organism rather than the media. There was no discernible impact of temperature-controlled (4-6°C) transport on the isolation of Sp from culture swabs. Conclusions The study clearly elucidates the ability of laboratories for isolation of S. pneumoniae on human blood agar in resource limited settings. The results highlight the difficulties inherent in correctly identifying pathogens in mixed cultures in needs improvement using standardized tests across the study centers. The study also reaffirms the ability to transport biological specimens over long geographical distances without loss.
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Affiliation(s)
| | - Sangeeta Joshi
- Consultant Microbiologist, Manipal Hospital, Bengaluru, Karnataka, India
| | - Madhuwanti N Abhyankar
- Consultant Microbiologist, Golwilkar Metropolis Health Services, (I) Pvt. Ltd., Pune, Maharashtra, India
| | - Ranjeeta Adhikary
- Consultant Microbiologist, Manipal Hospital, Bengaluru, Karnataka, India
| | - H B Beena
- Consultant Microbiologist, Manipal Hospital, Bengaluru, Karnataka, India
| | - T D Chugh
- Sr. Consultant, Department of Microbiology, BL Kapoor Memorial Hospital, New Delhi, India
| | - K D Gandhi
- Consultant Microbiologist, Shanti Mukund Hospital, New Delhi, India
| | - Vivek Hittinahalli
- Consultant Microbiologist, Yashomati Hospital, Bengaluru, Karnataka, India
| | - V A Indumathi
- M.S. Ramaiah Medical College, Bengaluru, Karnataka, India
| | | | - S Muralidharan
- St. John's Medical College Hospital, Bengaluru, Karnataka, India
| | - S S Rao
- SS Microbiology Laboratory, Thane, Maharashtra, India
| | - I Roy
- Consultant Microbiologist, Sri Aurobindo Seva Kendra, Kolkata, West Bengal, India
| | - N Saini
- Consultant Microbiologist, Pushpanjali Hospital, New Delhi, India
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Use of cerebrospinal fluid and serum samples impregnated on FTATM Elute filter paper for the diagnosis of infections caused by Neisseria meningitidis, Streptococcus pneumoniae and Haemophilus influenzae. PLoS One 2017; 12:e0172794. [PMID: 28235065 PMCID: PMC5325563 DOI: 10.1371/journal.pone.0172794] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/09/2017] [Indexed: 01/17/2023] Open
Abstract
Background The lack of information regarding the burden of acute bacterial meningitis in Latin America leads to a reduction in the estimated incidence rates of the disease, and impairs public health decisions on the use and follow-up of preventive interventions, particularly, the evaluation of existing vaccination policies. The use of the real-time PCR in diagnostic routine procedures has resulted in a substantial increase in confirmed bacterial meningitis cases. However, in resource-poor countries, these assays are only available in reference laboratories. Sample transportation to these laboratories is a critical constraint, as it requires specialized, high cost courier services. To overcome this barrier we evaluated the use of FTATM Elute filter paper cards for the conservation and processing of samples under normal environmental conditions, as they would be when transported from remote and under-equipped healthcare facilities to the reference centers. A total of 401 samples received in 2015 as part of Sao Paulo’s national surveillance for routine diagnosis were selected for this study. Methods The sensitivity and specificity of real-time PCR were evaluated using fresh serum and cerebrospinal fluid (CSF) samples processed using our laboratory’s standard DNA extraction, and processing the same samples after being dried and stored on FTATM card, and DNA extracted following the manufacturer’s instructions. Results The sensitivities for detection of Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae from CSF dried and stored on FTATM cards were 98%, 92%, and 100%, respectively, and with serum samples were 73%, 88%, and 100%, respectively. When compared to our laboratory’s standard methodology, results showed high concordance, with Kappa index ranges of 0.9877–1.00 for CSF, and 0.8004–1.00 for serum samples. Conclusion The use of FTATM cards for CSF and serum conservation and transport represents a rapid, reliable, and cost-effective alternative that will allow obtaining valuable epidemiological information that would otherwise be lost.
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Pre-cut Filter Paper for Detecting Anti-Japanese Encephalitis Virus IgM from Dried Cerebrospinal Fluid Spots. PLoS Negl Trop Dis 2016; 10:e0004516. [PMID: 26986061 PMCID: PMC4795698 DOI: 10.1371/journal.pntd.0004516] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/14/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The use of filter paper as a simple, inexpensive tool for storage and transportation of blood, 'Dried Blood Spots' or Guthrie cards, for diagnostic assays is well-established. In contrast, there are a paucity of diagnostic evaluations of dried cerebrospinal fluid (CSF) spots. These have potential applications in low-resource settings, such as Laos, where laboratory facilities for central nervous system (CNS) diagnostics are only available in Vientiane. In Laos, a major cause of CNS infection is Japanese encephalitis virus (JEV). We aimed to develop a dried CSF spot protocol and to evaluate its diagnostic performance using the World Health Organisation recommended anti-JEV IgM antibody capture enzyme-linked immunosorbent assay (JEV MAC-ELISA). METHODOLOGY AND PRINCIPAL FINDINGS Sample volumes, spotting techniques and filter paper type were evaluated using a CSF-substitute of anti-JEV IgM positive serum diluted in Phosphate Buffer Solution (PBS) to end-limits of detection by JEV MAC-ELISA. A conventional protocol, involving eluting one paper punch in 200 μl PBS, did not detect the end-dilution, nor did multiple punches utilising diverse spotting techniques. However, pre-cut filter paper enabled saturation with five times the volume of CSF-substitute, sufficiently improving sensitivity to detect the end-dilution. The diagnostic accuracy of this optimised protocol was compared with routine, neat CSF in a pilot, retrospective study of JEV MAC-ELISA on consecutive CSF samples, collected 2009-15, from three Lao hospitals. In comparison to neat CSF, 132 CSF samples stored as dried CSF spots for one month at 25-30 °C showed 81.6% (65.7-92.3 95%CI) positive agreement, 96.8% (91.0-99.3 95%CI) negative agreement, with a kappa coefficient of 0.81 (0.70-0.92 95%CI). CONCLUSIONS/SIGNIFICANCE The novel design of pre-cut filter paper saturated with CSF could provide a useful tool for JEV diagnostics in settings with limited laboratory access. It has the potential to improve national JEV surveillance and inform vaccination policies. The saturation of filter paper has potential use in the wider context of pathogen detection, including dried spots for detecting other analytes in CSF, and other body fluids.
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Krone CL, Oja AE, van de Groep K, Sanders EAM, Bogaert D, Trzciński K. Dried Saliva Spots: A Robust Method for Detecting Streptococcus pneumoniae Carriage by PCR. Int J Mol Sci 2016; 17:343. [PMID: 26959014 PMCID: PMC4813204 DOI: 10.3390/ijms17030343] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 02/23/2016] [Accepted: 03/01/2016] [Indexed: 01/29/2023] Open
Abstract
The earliest studies in the late 19th century on Streptococcus pneumoniae (S. pneumoniae) carriage used saliva as the primary specimen. However, interest in saliva declined after the sensitive mouse inoculation method was replaced by conventional culture, which made isolation of pneumococci from the highly polymicrobial oral cavity virtually impossible. Here, we tested the feasibility of using dried saliva spots (DSS) for studies on pneumococcal carriage. Saliva samples from children and pneumococcus-spiked saliva samples from healthy adults were applied to paper, dried, and stored, with and without desiccant, at temperatures ranging from -20 to 37 °C for up to 35 days. DNA extracted from DSS was tested with quantitative-PCR (qPCR) specifically for S. pneumoniae. When processed immediately after drying, the quantity of pneumococcal DNA detected in spiked DSS from adults matched the levels in freshly spiked raw saliva. Furthermore, pneumococcal DNA was stable in DSS stored with desiccant for up to one month over a broad range of temperatures. There were no differences in the results when spiking saliva with varied pneumococcal strains. The collection of saliva can be a particularly useful in surveillance studies conducted in remote settings, as it does not require trained personnel, and DSS are resilient to various transportation conditions.
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Affiliation(s)
- Cassandra L Krone
- Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands.
| | - Anna E Oja
- Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands.
| | - Kirsten van de Groep
- Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands.
| | - Elisabeth A M Sanders
- Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands.
| | - Debby Bogaert
- Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands.
| | - Krzysztof Trzciński
- Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands.
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Smit PW, Elliott I, Peeling RW, Mabey D, Newton PN. An overview of the clinical use of filter paper in the diagnosis of tropical diseases. Am J Trop Med Hyg 2014; 90:195-210. [PMID: 24366501 PMCID: PMC3919219 DOI: 10.4269/ajtmh.13-0463] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/04/2013] [Indexed: 12/16/2022] Open
Abstract
Tropical infectious diseases diagnosis and surveillance are often hampered by difficulties of sample collection and transportation. Filter paper potentially provides a useful medium to help overcome such problems. We reviewed the literature on the use of filter paper, focusing on the evaluation of nucleic acid and serological assays for diagnosis of infectious diseases using dried blood spots (DBS) compared with recognized gold standards. We reviewed 296 eligible studies and included 101 studies evaluating DBS and 192 studies on other aspects of filter paper use. We also discuss the use of filter paper with other body fluids and for tropical veterinary medicine. In general, DBS perform with sensitivities and specificities similar or only slightly inferior to gold standard sample types. However, important problems were revealed with the uncritical use of DBS, inappropriate statistical analysis, and lack of standardized methodology. DBS have great potential to empower healthcare workers by making laboratory-based diagnostic tests more readily accessible, but additional and more rigorous research is needed.
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Affiliation(s)
- Pieter W. Smit
- Leiden Cytology and Pathology Laboratory, Leiden, The Netherlands; London School of Hygiene and Tropical Medicine, London, United Kingdom; Lao-Oxford-Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic; Department of Infectious Diseases, Nottingham University Hospitals National Health Service Trust, Nottingham, United Kingdom; Centre for Tropical Medicine, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom
| | - Ivo Elliott
- Leiden Cytology and Pathology Laboratory, Leiden, The Netherlands; London School of Hygiene and Tropical Medicine, London, United Kingdom; Lao-Oxford-Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic; Department of Infectious Diseases, Nottingham University Hospitals National Health Service Trust, Nottingham, United Kingdom; Centre for Tropical Medicine, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom
| | | | | | - Paul N. Newton
- Leiden Cytology and Pathology Laboratory, Leiden, The Netherlands; London School of Hygiene and Tropical Medicine, London, United Kingdom; Lao-Oxford-Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic; Department of Infectious Diseases, Nottingham University Hospitals National Health Service Trust, Nottingham, United Kingdom; Centre for Tropical Medicine, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom
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Elliott I, Dittrich S, Paris D, Sengduanphachanh A, Phoumin P, Newton PN. The use of dried cerebrospinal fluid filter paper spots as a substrate for PCR diagnosis of the aetiology of bacterial meningitis in the Lao PDR. Clin Microbiol Infect 2013; 19:E466-72. [PMID: 23738720 PMCID: PMC4285853 DOI: 10.1111/1469-0691.12260] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 03/24/2013] [Accepted: 04/29/2013] [Indexed: 11/29/2022]
Abstract
We investigated whether dried cerebrospinal fluid (CSF) conserved on filter paper can be used as a substrate for accurate PCR diagnosis of important causes of bacterial meningitis in the Lao PDR. Using mock CSF, we investigated and optimized filter paper varieties, paper punch sizes, elution volumes and quantities of DNA template to achieve sensitive and reliable detection of bacterial DNA from filter paper specimens. FTA Elute Micro Card™ (Whatman, Maidstone, UK) was the most sensitive, consistent and practical variety of filter paper. Following optimization, the lower limit of detection for Streptococcus pneumoniae from dried mock CSF spots was 14 genomic equivalents (GE)/μL (interquartile range 5.5 GE/μL) or 230 (IQR 65) colony forming units/mL. A prospective clinical evaluation for S. pneumoniae, S. suis and Neisseria meningitidis was performed. Culture and PCR performed on fresh liquid CSF from patients admitted with a clinical diagnosis of meningitis (n = 73) were compared with results derived from dried CSF spots. Four of five fresh PCR-positive CSF samples also tested PCR positive from dried CSF spots, with one patient under the limit of detection. In a retrospective study of S. pneumoniae samples (n = 20), the median (IQR; range) CSF S. pneumoniae bacterial load was 1.1 × 10(4) GE/μL (1.2 × 10(5) ; 1 to 6.1 × 10(6) DNA GE/μL). Utilizing the optimized methodology, we estimate an extrapolated sensitivity of 90%, based on the range of CSF genome counts found in Laos. Dried CSF filter paper spots could potentially help us to better understand the epidemiology of bacterial meningitis in resource-poor settings and guide empirical treatments and vaccination policies.
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Affiliation(s)
- I Elliott
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR; Centre for Tropical Medicine, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, UK
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Pääkkönen M, Kallio MJT, Kallio PE, Peltola H. Shortened hospital stay for childhood bone and joint infections: Analysis of 265 prospectively collected culture-positive cases in 1983–2005. ACTA ACUST UNITED AC 2012; 44:683-8. [DOI: 10.3109/00365548.2012.673729] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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