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Kim HJ, Jung Y, Kim MJ, Kim HY. Novel Heptaplex PCR-Based Diagnostics for Enteric Fever Caused by Typhoidal Salmonella Serovars and Its Applicability in Clinical Blood Culture. J Microbiol Biotechnol 2023; 33:1457-1466. [PMID: 37674393 DOI: 10.4014/jmb.2307.07031] [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] [Received: 07/24/2023] [Revised: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 09/08/2023]
Abstract
Enteric fever is caused by typhoidal Salmonella serovars (Typhi, Paratyphi A, Paratyphi B, and Paratyphi C). Owing to the importance of Salmonella serovars in clinics and public hygiene, reliable diagnostics for typhoidal serovars are crucial. This study aimed to develop a novel diagnostic tool for typhoidal Salmonella serovars and evaluate the use of human blood for clinically diagnosing enteric fever. Five genes were selected to produce specific PCR results against typhoidal Salmonella serovars based on the genes of Salmonella Typhi. Heptaplex PCR, including genetic markers of generic Salmonella, Salmonella enterica subsp. enterica, and typhoidal Salmonella serovars, was developed. Typhoidal Salmonella heptaplex PCR using genomic DNAs from 200 Salmonella strains (112 serovars) provided specifically amplified PCR products for each typhoidal Salmonella serovar. These results suggest that heptaplex PCR can sufficiently discriminate between typhoidal and nontyphoidal Salmonella serovars. Heptaplex PCR was applied to Salmonella-spiked blood cultures directly and provided diagnostic results after 12- or 13.5-h blood culture. Additionally, it demonstrated diagnostic performance with colonies recovered from a 6-h blood culture. This study provides a reliable DNA-based tool for diagnosing typhoidal Salmonella serovars that may be useful in clinical microbiology and epidemiology.
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Affiliation(s)
- Hyun-Joong Kim
- Department of Food Engineering, Mokpo National University, Muan 58554, Republic of Korea
| | - Younsik Jung
- Institute of Life Sciences and Resources and the Department of Food Science and Biotechnology, Kyung Hee University, Yongin 17104 Republic of Korea
| | - Mi-Ju Kim
- Institute of Life Sciences and Resources and the Department of Food Science and Biotechnology, Kyung Hee University, Yongin 17104 Republic of Korea
| | - Hae-Yeong Kim
- Institute of Life Sciences and Resources and the Department of Food Science and Biotechnology, Kyung Hee University, Yongin 17104 Republic of Korea
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Igiri BE, Okoduwa SIR, Munirat SA, Otu-Bassey IB, Bashir A, Onyiyioza OM, Enang IA, Okoduwa UJ. Diversity in Enteric Fever Diagnostic Protocols and Recommendation for Composite Reference Standard. IRANIAN JOURNAL OF MEDICAL MICROBIOLOGY 2023; 17:22-38. [DOI: 10.30699/ijmm.17.1.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Liaquat S, Sarwar Y, Ali A, Haque A, Farooq M, Martinez-Ballesteros I, Laorden L, Garaizar J, Bikandi J. Virulotyping of Salmonella enterica serovar Typhi isolates from Pakistan: Absence of complete SPI-10 in Vi negative isolates. PLoS Negl Trop Dis 2018; 12:e0006839. [PMID: 30500817 PMCID: PMC6267989 DOI: 10.1371/journal.pntd.0006839] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 09/13/2018] [Indexed: 12/30/2022] Open
Abstract
The pathogenesis of Salmonella enterica serovar Typhi (S. Typhi), the cause of typhoid fever in humans, is mainly attributed to the acquisition of horizontally acquired DNA elements. Salmonella pathogenicity islands (SPIs) are indubitably the most important form of horizontally acquired DNA with respect to pathogenesis of this bacterium. The insertion or deletion of any of these transferrable SPIs may have impact on the virulence potential of S. Typhi. In this study, the virulence potential and genetic relatedness of 35 S. Typhi isolates, collected from 2004 to 2013 was determined by identification of SPI and non-SPI virulence factors through a combination of techniques including virulotyping, Whole Genome Sequencing (WGS), and Variable Number of Tandem Repeats (VNTR) profiling. In order to determine the virulence potential of local S. Typhi isolates, 56 virulence related genes were studied by PCR. These genes are located in the core as well as accessory genome (SPIs and plasmid). Major variations among studied virulence determinants were found in case of SPI-7 and SPI-10 associated genes. On the basis of presence of virulence related genes, the studied S. Typhi isolates from Pakistan were clustered into two virulotypes Vi-positive and Vi-negative. Interestingly, SPI-7 and SPI-10 were collectively absent or present in Vi-negative and Vi-positive strains, respectively. Two Vi-negative and 11 Vi-positive S. Typhi strains were also analyzed by whole genome sequencing (WGS) and their results supported the PCR results. Genetic diversity was tested by VNTR-based molecular typing. All 35 isolates were clustered into five groups. Overall, all Vi-negative isolates were placed in a single group (T5) whereas Vi-positive isolates were grouped into four types. Vi-negative and Vi-positive isolates were mutually exclusive. This is the first report on the comparative distribution of SPI and non-SPI related virulence genes in Vi-negative and Vi-positive S. Typhi isolates with an important finding that SPI-10 is absent in all Vi-negative isolates. The distribution of virulence factors in S. Typhi can vary in isolates from different geographical regions and can have significant effect on the disease control. In this study, we have checked the distribution of 56 reported virulence associated factors in 35 local isolates of S. Typhi to identify any variations that can help in designing effective control strategies for typhoid. We have identified four naturally occurring variants which are simultaneously lacking SPI-7 and SPI-10, two adjacently located pathogenicity islands on S. Typhi chromosome. These isolates are not producing Vi capsular antigen hence the Vi based vaccines will not be effective against them. These findings highlight the need to develop typhoid vaccines specifically effective in Pakistan.
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Affiliation(s)
- Sadia Liaquat
- Enteric Pathogen Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan affiliated with Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
- Departments of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Yasra Sarwar
- Enteric Pathogen Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan affiliated with Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
- * E-mail:
| | - Aamir Ali
- Enteric Pathogen Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan affiliated with Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Abdul Haque
- Akhuwat Faisalabad Institute For Research In Science And Technology, Faisalabad, Pakistan
| | - Muhammad Farooq
- Enteric Pathogen Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan affiliated with Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Ilargi Martinez-Ballesteros
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country, (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Lorena Laorden
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country, (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Javier Garaizar
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country, (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Joseba Bikandi
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country, (UPV/EHU), Vitoria-Gasteiz, Spain
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Development of Inhouse Immunoblot Method for Detection of Anti Salmonella Antibody and Comparison with Widal Test. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2018. [DOI: 10.22207/jpam.12.3.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Prabagaran SR, Kalaiselvi V, Chandramouleeswaran N, Deepthi KNG, Brahmadathan KN, Mani M. Molecular diagnosis of Salmonella typhi and its virulence in suspected typhoid blood samples through nested multiplex PCR. J Microbiol Methods 2017; 139:150-154. [PMID: 28545919 DOI: 10.1016/j.mimet.2017.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 05/19/2017] [Accepted: 05/22/2017] [Indexed: 10/19/2022]
Abstract
A nested multiplex polymerase chain reaction (PCR) based diagnosis was developed for the detection of virulent Salmonella typhi in the blood specimens from patients suspected for typhoid fever. After the Widal test, two pairs of primers were used for the detection of flagellin gene (fliC) of S. typhi. Among them, those positive for fliC alone were subjected to identification of genes in Via B operon of Salmonella Pathogenesity Island (SPI-7) where four primer pairs were used to detect tviA and tviB genes. Among 250 blood samples tested, 115 were positive by fliC PCR; 22 of these were negative for tviA and tviB. Hence, the method described here can be used to diagnose the incidence of Vi-negative serovar typhi especially in endemic regions where the Vi vaccine is administered.
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Affiliation(s)
| | - Vellingiri Kalaiselvi
- Department of Biotechnology, Bharathiar University, Coimbatore, Tamilnadu 641 046, India
| | | | | | | | - Mariappa Mani
- Microbiological Laboratory, Cowley Brown Road (East), R. S. Puram, Coimbatore- 641 002, India
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Rehman A, Sarwar Y, Raza ZA, Hussain SZ, Mustafa T, Khan WS, Ghauri MA, Haque A, Hussain I. Metal nanoparticle assisted polymerase chain reaction for strain typing of Salmonella Typhi. Analyst 2016; 140:7366-72. [PMID: 26381602 DOI: 10.1039/c5an01286d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Salmonella enterica serotype Typhi (S. Typhi) is the causative agent of typhoid fever and remains a major health threat in most of the developing countries. The prompt diagnosis of typhoid directly from the patient's blood requires high level of sensitivity and specificity. Some of us were the first to report PCR based diagnosis of typhoid. This approach has since then been reported by many scientists using different genomic targets. Since the number of bacteria circulating in the blood of a patient can be as low as 0.3 cfu ml(-1), there is always a room for improvement in diagnostic PCR. In the present study, the role of different types of nanoparticles was investigated to improve the existing PCR based methods for diagnosis and strain typing of S. Typhi (targeting Variable Number of Tandem Repeats [VNTR]) by using optimized PCR systems. Three different types of nanoparticles were used i.e., citrate stabilized gold nanoparticles, rhamnolipid stabilized gold and silver nanoparticles, and magnetic iron oxide nanoparticles. The non-specific amplification was significantly reduced in VNTR typing when gold and silver nanoparticles were used in an appropriate concentration. More importantly, the addition of nanoparticles decreased the non-specificity to a significant level in the case of multiplex PCR thus further validating the reliability of PCR for the diagnosis of typhoid.
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Affiliation(s)
- Asma Rehman
- Nanobiotech Group, National Institute for Biotechnology & Genetic Engineering (NIBGE), Jhang Road, Faisalabad, Pakistan
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Storey HL, Huang Y, Crudder C, Golden A, de los Santos T, Hawkins K. A Meta-Analysis of Typhoid Diagnostic Accuracy Studies: A Recommendation to Adopt a Standardized Composite Reference. PLoS One 2015; 10:e0142364. [PMID: 26566275 PMCID: PMC4643909 DOI: 10.1371/journal.pone.0142364] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/21/2015] [Indexed: 01/09/2023] Open
Abstract
Novel typhoid diagnostics currently under development have the potential to improve clinical care, surveillance, and the disease burden estimates that support vaccine introduction. Blood culture is most often used as the reference method to evaluate the accuracy of new typhoid tests; however, it is recognized to be an imperfect gold standard. If no single gold standard test exists, use of a composite reference standard (CRS) can improve estimation of diagnostic accuracy. Numerous studies have used a CRS to evaluate new typhoid diagnostics; however, there is no consensus on an appropriate CRS. In order to evaluate existing tests for use as a reference test or inclusion in a CRS, we performed a systematic review of the typhoid literature to include all index/reference test combinations observed. We described the landscape of comparisons performed, showed results of a meta-analysis on the accuracy of the more common combinations, and evaluated sources of variability based on study quality. This wide-ranging meta-analysis suggests that no single test has sufficiently good performance but some existing diagnostics may be useful as part of a CRS. Additionally, based on findings from the meta-analysis and a constructed numerical example demonstrating the use of CRS, we proposed necessary criteria and potential components of a typhoid CRS to guide future recommendations. Agreement and adoption by all investigators of a standardized CRS is requisite, and would improve comparison of new diagnostics across independent studies, leading to the identification of a better reference test and improved confidence in prevalence estimates.
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Affiliation(s)
- Helen L. Storey
- Diagnostics Program, PATH, Seattle, Washington, United States of America
- * E-mail:
| | - Ying Huang
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Chris Crudder
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Allison Golden
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Tala de los Santos
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Kenneth Hawkins
- Diagnostics Program, PATH, Seattle, Washington, United States of America
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Ganesan V, Harish BN, Menezes GA, Parija SC. Detection of Salmonella in Blood by PCR using iroB gene. J Clin Diagn Res 2014; 8:DC01-3. [PMID: 25584214 DOI: 10.7860/jcdr/2014/9191.5086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 09/10/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND Salmonella, a genus of more than 2500 serological variants (serovars), includes many organisms that can cause human disease. Enteric fever remains an important public health problem in developing countries. Non typhoidal Salmonella generally produce a self limited gastroenteritis in healthy individuals whereas in extremes of age and immunocompromised cause severe fatal disease. The protean manifestations make this disease a true diagnostic challenge. AIM The present study was carried out to optimize PCR for detecting the Salmonella genus using iroB gene and evaluate its use in the rapid diagnosis of typhoid and non typhoidal salmonellosis. MATERIALS AND METHODS The study was carried out between August 2009 and July 2011 on blood samples from patients attending JIPMER hospital, Pondicherry, India with clinical suspicion of enteric fever and salmonellosis. Whole blood was used DNA extraction and conventional PCR done with iroB and fliC primers. Blood culture and Widal test were performed for all the patients. STATISTICAL ANALYSIS Performed using Fischer's exact test with Graphpad Instat 3. RESULTS PCR results were compared with blood culture. Sensitivity and specificity of PCR with fliC gene are 95.6% and 93.3% respectively. Sensitivity and specificity of PCR with iroB gene are 96.6% and 93.3% respectively CONCLUSION With iroB gene, additional cases of Salmonella Paratyphi A and non typhoidal Salmonella were detected when compared to fliC gene.
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Affiliation(s)
- Vithiya Ganesan
- Assistant Professor, Department of Microbiology, Velammal Medical College Hospital and Research Institute , Madurai, India
| | - Belgode Narasimha Harish
- Head of the Department, Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Science and Research , Puducherry, India
| | - Godfred Antony Menezes
- Assistant Professor, College of Applied Medical Sciences, University of Ha'il, Ha'il , Kingdom of Saudi Arabia (KSA)
| | - Subash Chandra Parija
- Dean, Jawaharlal Institute of Postgraduate Medical Science and Research , Puducherry, India
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Parry CM, Wijedoru L, Arjyal A, Baker S. The utility of diagnostic tests for enteric fever in endemic locations. Expert Rev Anti Infect Ther 2014; 9:711-25. [DOI: 10.1586/eri.11.47] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Affiliation(s)
- Bhavna Dhingra
- Department of Pediatrics, Maulana Azad Medical College, and Associated Chacha Nehru Bal Chikitsalaya and Lok Nayak Hospital, New Delhi, India.
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Application of a 16S rRNA PCR-high-resolution melt analysis assay for rapid detection of Salmonella Bacteremia. J Clin Microbiol 2012; 50:1122-4. [PMID: 22205823 DOI: 10.1128/jcm.05121-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Current culture and phenotypic protocols for diagnosing Salmonella infections can be time-consuming. Here, we describe the application of a 16S rRNA PCR coupled to high-resolution melt analysis (HRMA) for species and serotype identification within 6 h of blood sample collection from a patient with Salmonella enterica serotype Enteritidis bacteremia.
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Raza A, Sarwar Y, Ali A, Jamil A, Haque A, Haque A. Effect of biofilm formation on the excretion of Salmonella enterica serovar Typhi in feces. Int J Infect Dis 2011; 15:e747-52. [PMID: 21816646 DOI: 10.1016/j.ijid.2011.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 03/25/2011] [Accepted: 06/06/2011] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVES We hypothesized that Salmonella enterica serovar Typhi (S. Typhi) with higher biofilm and capsule production capability are more able to survive continuously in typhoid patients/carriers, with subsequent prolonged shedding in feces. METHODS Bacterial cell release from biofilm (produced in vitro and confirmed by specific staining and electron microscopy) and comparative cytotoxicity were studied on Caco2 cells. Functionality of the biofilm diffusion barrier was tested against ciprofloxacin. Biofilm production was graded and semi-quantified as -, +, ++, +++, and ++++. RESULTS Out of 30 isolates, 23 produced biofilm. The average post-treatment detection of S. Typhi in blood was 7-13 days and in stool was 13-32 days. A fall in cell count from 10⁴ to approximately 10¹ over the course of 3 days as compared to total elimination of planktonic cells in 16 h after ciprofloxacin application substantiated the protective role of biofilm. Lactic dehydrogenase release ranged from 38% in non-biofilm producers to 97% in the highest biofilm producers, indicating increased pathogenic behavior. CONCLUSIONS The period of S. Typhi clearance from typhoid patients after recovery was found to be directly related to biofilm production capability.
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Affiliation(s)
- Abida Raza
- Molecular Diagnostics and Research Laboratory, Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad, Pakistan
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Nga TVT, Karkey A, Dongol S, Thuy HN, Dunstan S, Holt K, Tu LTP, Campbell JI, Chau TT, Chau NVV, Arjyal A, Koirala S, Basnyat B, Dolecek C, Farrar J, Baker S. The sensitivity of real-time PCR amplification targeting invasive Salmonella serovars in biological specimens. BMC Infect Dis 2010; 10:125. [PMID: 20492644 PMCID: PMC2886058 DOI: 10.1186/1471-2334-10-125] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 05/21/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND PCR amplification for the detection of pathogens in biological material is generally considered a rapid and informative diagnostic technique. Invasive Salmonella serovars, which cause enteric fever, can be commonly cultured from the blood of infected patients. Yet, the isolation of invasive Salmonella serovars from blood is protracted and potentially insensitive. METHODS We developed and optimised a novel multiplex three colour real-time PCR assay to detect specific target sequences in the genomes of Salmonella serovars Typhi and Paratyphi A. We performed the assay on DNA extracted from blood and bone marrow samples from culture positive and negative enteric fever patients. RESULTS The assay was validated and demonstrated a high level of specificity and reproducibility under experimental conditions. All bone marrow samples tested positive for Salmonella, however, the sensitivity on blood samples was limited. The assay demonstrated an overall specificity of 100% (75/75) and sensitivity of 53.9% (69/128) on all biological samples. We then tested the PCR detection limit by performing bacterial counts after inoculation into blood culture bottles. CONCLUSIONS Our findings corroborate previous clinical findings, whereby the bacterial load of S. Typhi in peripheral blood is low, often below detection by culture and, consequently, below detection by PCR. Whilst the assay may be utilised for environmental sampling or on differing biological samples, our data suggest that PCR performed directly on blood samples may be an unsuitable methodology and a potentially unachievable target for the routine diagnosis of enteric fever.
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Affiliation(s)
- Tran Vu Thieu Nga
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
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Cardona-Castro N, Sánchez-Jiménez M, Lavalett L, Múñoz N, Moreno J. Development and evaluation of a multiplex polymerase chain reaction assay to identify Salmonella serogroups and serotypes. Diagn Microbiol Infect Dis 2010; 65:327-30. [PMID: 19822272 DOI: 10.1016/j.diagmicrobio.2009.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 07/01/2009] [Accepted: 07/06/2009] [Indexed: 11/24/2022]
Abstract
To improve limitations of Salmonella serotyping, 2 multiplex polymerase chain reaction (M-PCR) were developed using a strategy that identifies first the genes encoding serogroups (rfbJ, wzx). According to the serogroup determined, a second M-PCR identifies serotype (fliC, fljB, wcdB, and sdf-I sequence). Standardization and evaluation of both M-PCRs were carried out.
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Affiliation(s)
- Nora Cardona-Castro
- Laboratorio de Microbiología, Instituto Colombiano de Medicina Tropical - Universidad CES Cra 43 A #52 Sur 99, Medellín, Colombia.
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Multiplex PCR for differential diagnosis of emerging typhoidal pathogens directly from blood samples. Epidemiol Infect 2008; 137:102-7. [PMID: 18413005 DOI: 10.1017/s0950268808000654] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Classically Salmonella enterica serovar Typhi (S. Typhi) is associated with typhoid, a major health problem in developing countries. However, in recent years S. Paratyphi A and Vi-negative variants of S. Typhi have emerged rapidly. We have developed a nested multiplex PCR targeting five different genes for differential diagnosis of typhoidal pathogens which has been optimized to be directly applicable on clinical blood samples. Of 42 multiplex PCR-positive blood samples, 26, nine, and two were Vi-positive S. Typhi, Vi-negative S. Typhi and S. Paratyphi A, respectively, and five patients were found to have mixed infection. Seventeen patients grew Salmonella from blood culture and the remaining 25 were positive in the Salmonella-specific PCR. Tests with several common pathogens confirmed the specificity of the assay. We conclude that the proposed multiplex PCR is rapid, sensitive and specific for the diagnosis of typhoidal pathogens directly from blood samples.
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Aziah I, Ravichandran M, Ismail A. Amplification of ST50 gene using dry-reagent-based polymerase chain reaction for the detection of Salmonella typhi. Diagn Microbiol Infect Dis 2007; 59:373-7. [PMID: 17964105 DOI: 10.1016/j.diagmicrobio.2007.05.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2007] [Revised: 05/28/2007] [Accepted: 05/29/2007] [Indexed: 11/28/2022]
Abstract
Conventional polymerase chain reaction (PCR) testing requires many pipetting steps and has to be transported and stored in cold chain. To overcome these limitations, we designed a ready-to-use PCR test for Salmonella typhi using PCR reagents, primers against the ST50 gene of S. typhi, a built-in internal amplification control (IAC), and gel loading dye mixed and freeze-dried in a single tube. The 2-step dry-reagent-based assay was used to amplify a 1238-bp target gene and an 810-bp IAC gene from 73 BACTEC blood culture broths (33 true positives for S. typhi and 40 true negatives for non-S. typhi). The sensitivity, specificity, positive predictive value, and negative predictive value of the PCR assay were 87.9%, 100%, 100%, and 90.9%, respectively. We suggest that this rapid 2-step PCR test could be used for the rapid diagnosis of typhoid fever.
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Affiliation(s)
- Ismail Aziah
- Institute for Research in Molecular Medicine, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
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Abstract
OBJECTIVE To determine the efficacy of nested polymerase chain reaction (PCR) in detecting Salmonella typhi gene sequences in blood and urine specimens and to determine the cut-off titer of Widal test using PCR as gold standard test for diagnosis of typhoid fever. METHODS Study included 71 children between the ages of 8 months and 14 years; 52 of them were suspected cases of typhoid fever, 11 were febrile non-typhoid controls and 8 were apparently healthy children. Nested PCR in Blood and Urine, Blood culture, Widal test and Urine culture were done and their results analyzed. RESULTS Among suspected typhoid cases, PCR in blood and urine had positivity of 82.7% each. Blood culture, Widal test (at cut off titer TO and/or TH > 1:160) and urine culture had positivity of 26.9%, 50% and 3.8% respectively. In one case, urine PCR was positive and blood PCR was negative. Similarly, in another case, PCR in blood was positive however urine tested negative. Considering PCR as gold standard, the antibody cut off titer was evaluated. A cut-off titer of TO > 1:80 and/or TH > 1:160 had sensitivity and specificity of 72.7% and 84.2%, while the respective figures were 50% and 89.5% when the cut-off titer was TO and/or TH > 1:160. CONCLUSION The sensitivity, specificity, positive and negative predictive values, likelihood ratios were same for PCR based detection of S. typhi in blood and urine samples. Nested PCR had higher efficacy in detecting typhoid fever than Widal test, blood and urine cultures. A cut off titer of TO > 1:80 and/or TH > 1:160 was found to have better diagnostic value in this region.
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Affiliation(s)
- S R Ambati
- Miami Childrens Hospital, Miami, FL, USA.
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DONG B, GALINDO C, SHIN E, ACOSTA C, PAGE A, WANG M, KIM D, OCHIAI R, PARK J, ALI M, SEIDLEIN L, XU Z, YANG J, CLEMENS J. Optimizing typhoid fever case definitions by combining serological tests in a large population study in Hechi City, China. Epidemiol Infect 2007; 135:1014-20. [PMID: 17217551 PMCID: PMC2870657 DOI: 10.1017/s0950268806007801] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Blood culture-based diagnosis can only detect a fraction of the total burden of Salmonella enterica subsp. enterica serovar Typhi. The objective of the study was to detect additional typhoid fever cases through serological tests. A total of 1732 prolonged fever episodes were evaluated using three serological tests, Widal, Tubex and Typhidot-M in a typhoid fever endemic area of southern China. A case definition which included a positive Widal test (TO>or=80 & TH>A), a positive Tubex test (>or=4) and a positive Typhidot-M test, increased the detection of cases by more than twofold from 13 to 28 cases. The case definition has a specificity of 100% and a sensitivity of 39%. Case definitions based on combinations of serological tests can detect additional typhoid fever cases with higher specificity than a single serological test. Improved case detection is essential to understand the true disease burden and can help to boost the power of intervention trials.
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Affiliation(s)
- B. DONG
- Guangxi Center for Disease Prevention and Control, Nanning, Guangxi, China
| | | | - E. SHIN
- International Vaccine Institute, Seoul, Korea
- School of Public Health and Institute of Health and Environment, Seoul National University, Seoul, Korea
- Author for correspondence: Ms E. Shin, International Vaccine Institute, Research Park, San 4-8 Bongcheon-7 dong, Kwanak-gu, Seoul, Korea 151-818. ()
| | | | - A. L. PAGE
- International Vaccine Institute, Seoul, Korea
| | - M. WANG
- Guangxi Center for Disease Prevention and Control, Nanning, Guangxi, China
| | - D. KIM
- International Vaccine Institute, Seoul, Korea
| | | | - J. PARK
- International Vaccine Institute, Seoul, Korea
| | - M. ALI
- International Vaccine Institute, Seoul, Korea
| | | | - Z. XU
- International Vaccine Institute, Seoul, Korea
| | - J. YANG
- Guangxi Center for Disease Prevention and Control, Nanning, Guangxi, China
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19
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Prakash P, Mishra OP, Singh AK, Gulati AK, Nath G. Evaluation of nested PCR in diagnosis of typhoid fever. J Clin Microbiol 2005; 43:431-2. [PMID: 15635006 PMCID: PMC540097 DOI: 10.1128/jcm.43.1.431-432.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, nested PCR using H1-d primers, which is specific for Salmonella enterica serovar Typhi, was compared to blood culture and the single-tube Widal test. Results indicate that nested PCR can be used as a gold standard to determine the cutoff titer of the Widal test for diagnosis of typhoid fever.
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Affiliation(s)
- Pradyot Prakash
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India.
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20
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Sánchez-Jiménez MM, Cardona-Castro N. Validation of a PCR for diagnosis of typhoid fever and salmonellosis by amplification of the hilA gene in clinical samples from Colombian patients. J Med Microbiol 2004; 53:875-878. [PMID: 15314194 DOI: 10.1099/jmm.0.45630-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Validation of a PCR test to detect hilA gene sequences of Salmonella spp. was performed in blood and faeces samples from typhoid fever and salmonellosis patients. Sensitivity (S), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) of the PCR in blood samples were performed by testing: 37 patients with clinical diagnosis of typhoid fever, 34 of them confirmed by isolation of S. Typhi from blood cultures; 35 patients infected with other pathogens corroborated by blood culture (Klebsiella pneumoniae, 9; Serratia marcescens, 5; Escherichia coli, 4; Pseudomonas aeruginosa, 9; Providencia alcalifaciens, 4 and Enterobacter cloacae, 4) and blood samples from 150 healthy volunteers. To evaluate S, SP, PPV and NPV of the PCR in faeces samples we studied: 34 patients with enteritis due Salmonella spp. (S. Typhimurium, 21; S. Enteritidis, 9; S. Choleraesuis, 3 and S. Agona, 1); faeces samples from 35 patients with enteric infection due to Shigella sonnei (8), Shigella flexneri (10), enteropathogenic E. coli (12), Aeromonas hydrophila (5) and faeces samples from 150 healthy volunteers. The S, SP, PPV and NPV of the PCR in blood samples were all 100 %. PCR detected three patients with clinical diagnosis of typhoid fever and negative blood cultures. In faeces samples, S was 97 %, SP 100 %, PPV 100 % and NPV 99 %. The lowest number of c.f.u. ml(-1) detected by PCR in blood samples was 1 x 10(1) and in faeces samples 4 x 10(2).
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Affiliation(s)
- M M Sánchez-Jiménez
- Laboratorio de Microbiología, Instituto Colombiano de Medicina Tropical, Cra 43a No. 52 Sur 99, Sabaneta, Colombia 2Facultad de Medicina Universidad de Antioquia Programa de Maestría Ciencias Básicas Biomédicas, Colombia 3Instituto de Ciencias de la Salud CES, Medellín, Colombia
| | - Nora Cardona-Castro
- Laboratorio de Microbiología, Instituto Colombiano de Medicina Tropical, Cra 43a No. 52 Sur 99, Sabaneta, Colombia 2Facultad de Medicina Universidad de Antioquia Programa de Maestría Ciencias Básicas Biomédicas, Colombia 3Instituto de Ciencias de la Salud CES, Medellín, Colombia
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21
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Massi MN, Shirakawa T, Gotoh A, Bishnu A, Hatta M, Kawabata M. Rapid diagnosis of typhoid fever by PCR assay using one pair of primers from flagellin gene of Salmonella typhi. J Infect Chemother 2003; 9:233-7. [PMID: 14513391 DOI: 10.1007/s10156-003-0256-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2002] [Accepted: 06/03/2003] [Indexed: 11/26/2022]
Abstract
Using the polymerase chain reaction (PCR) assay, we developed a rapid diagnosis method for Salmonella typhi infection in blood specimens from patients with typhoid fever. Primers were designed from the flagellin gene sequence, which would give an amplification product of 367 base pairs. In this study, the specificity of the assay, with no amplification, was seen for the other Salmonella strains with the flagellin gene, and not for non- Salmonella bacteria. For the sensitivity test, the protocol described allowed the detection of two to three copies of the Salmonella typhi genome, as determined by serial dilution of genomic DNA from Salmonella typhi. With the PCR technique, genomic DNA of Salmonella typhi was detected in 46 of 73 blood samples collected from patients with clinically suspected typhoid fever who had fever within 3 days of admission to the General Hospital, Makassar, South Sulawesi, Indonesia, and who had had no prior antibiotic treatment. The PCR results (63% positive cases) were compared with those of blood culture (13.7% positive cases) and the Widal test (35.6% positive cases), using the same samples from each of the 73 patients admitted to the General Hospital in Makassar. The time taken for PCR analysis of each sample was less than 12 h, compared with 3 to 5 days for blood or clot culture. The PCR with one pair of primers can be used as a novel, rapid diagnostic method for typhoid fever, particularly when results of standard culture assays are negative.
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Affiliation(s)
- Muhammad Nasrum Massi
- International Center for Medical Research, Kobe University School of Medicine, Kobe, Japan
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