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Jiang Y, Jiang M, Cai R, Shi X, Hu Q, Kan B. Rapid and specific differentiation of Salmonella enterica serotypes typhi and Paratyphi by multicolor melting curve analysis. Gut Pathog 2024; 16:43. [PMID: 39160630 PMCID: PMC11331607 DOI: 10.1186/s13099-024-00636-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 07/29/2024] [Indexed: 08/21/2024] Open
Abstract
Rapid and accurate identification of Salmonella enterica serotypes Typhi and Paratyphi (A, B and C), the causal agents of enteric fever, is critical for timely treatment, case management and evaluation of health policies in low and middle-income countries where the disease still remains a serious public health problem. The present study describes the development of a multiplex assay (EFMAtyping) for simultaneous identification of pathogens causing typhoid and paratyphoid fever in a single reaction by the MeltArray approach, which could be finished within 2.5 h. Seven specific genes were chosen for differentiation of typhoidal and nontyphoidal Salmonella. All gene targets were able to be detected by the EFMAtyping assay, with expected Tm values and without cross-reactivity to other relevant Salmonella serovars. The limit of detection (LOD) for all gene targets was 50 copies per reaction. The LOD reached 102-103 CFU/ml for each pathogen in simulated clinical samples. The largest standard deviation value for mean Tm was below 0.5 °C. This newly developed EFMAtyping assay was further evaluated by testing 551 clinical Salmonella isolates, corroborated in parallel by the traditional Salmonella identification workflow, and serotype prediction was enabled by whole-genome sequencing. Compared to the traditional method, our results exhibited 100% of specificity and greater than 96% of sensitivity with a kappa correlation ranging from 0.96 to 1.00. Thus, the EFMAtyping assay provides a rapid, high throughput, and promising tool for public health laboratories to monitor typhoid and paratyphoid fever.
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Affiliation(s)
- Yixiang Jiang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
- Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China
| | - Min Jiang
- Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China
| | - Rui Cai
- Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China
| | - Xiaolu Shi
- Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China
| | - Qinghua Hu
- Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China.
| | - Biao Kan
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
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2
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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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3
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Higginson EE, Nkeze J, Permala-Booth J, Kasumba IN, Lagos R, Hormazabal JC, Byrne A, Frankel G, Levine MM, Tennant SM. Detection of Salmonella Typhi in Bile by Quantitative Real-Time PCR. Microbiol Spectr 2022; 10:e0024922. [PMID: 35639002 PMCID: PMC9241738 DOI: 10.1128/spectrum.00249-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/06/2022] [Indexed: 11/20/2022] Open
Abstract
In countries where the incidence of typhoid fever is high, fecal material from short-term carriers of Salmonella Typhi contaminates inadequately treated water supplies. As treated water supplies and improved sanitation become available, chronic (mainly gallbladder) carriers of S. Typhi become important. The objective of this study was to develop a method for detection of S. Typhi in bile by quantitative real-time PCR (qPCR) in patients undergoing cholecystectomy. We evaluated sensitivity and specificity of probesets that target oriC, viaB, fliC-d, STY0201, and stoD. We optimized DNA extraction from bile and compared the sensitivity of culture and our qPCR method to detect S. Typhi in bile samples containing various cephalosporins. With the use of an optimized DNA extraction technique, our limit of detection of S. Typhi in spiked human bile samples was 7.4 × 102 CFU/mL. We observed that S. Typhi could be detected by qPCR in samples containing cefazolin, cefotaxime, or ceftriaxone whereas culture could only detect Typhi in samples containing cefazolin but not cefotaxime or ceftriaxone. Our qPCR detection method for S. Typhi in bile should be preferred in areas where antibiotic usage is common. IMPORTANCE New Salmonella Typhi conjugate vaccines have been deployed, which will potentially lead to a fall in incidence rates of typhoid fever in endemic areas. Identification of chronic carriers of S. Typhi will be important as these individuals can be a potential source of transmission to susceptible persons. To address this public health concern, we have developed a novel method to detect S. Typhi in bile using real-time PCR. Our method can be used to identify carriers of S. Typhi among patients undergoing cholecystectomy (gallbladder removal surgery). The sensitivity of our molecular-based assay was superior to culture when performed in the presence of antibiotics commonly used during surgery. Our methodology will complement efforts to eliminate typhoid disease.
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Affiliation(s)
- Ellen E. Higginson
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Joseph Nkeze
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jasnehta Permala-Booth
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Irene N. Kasumba
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Rosanna Lagos
- Centro de Vacunas en Desarollo, Hospital de Ninos Roberto del Rio, Santiago, Chile
| | | | - Alexander Byrne
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Myron M. Levine
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Sharon M. Tennant
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
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4
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Evaluation of the different methods to detect Salmonella in poultry feces samples. Arch Microbiol 2022; 204:269. [PMID: 35441892 DOI: 10.1007/s00203-022-02840-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 03/12/2022] [Accepted: 03/13/2022] [Indexed: 11/02/2022]
Abstract
Salmonella is one of the most common causes of foodborne outbreaks and infection worldwide. The gold-standard detection method of Salmonella is cultivation. There is a need to investigate rapid and accurate processes with time-consuming cultivation. The study evaluated different approaches to detect Salmonella in poultry feces samples. Poultry farm feces samples from 21 cities in Iran were collected from January 2016 to December 2019. Microbiological cultures, serological assays, and multiplex PCR (m-PCR) were used to detect and characterize Salmonella spp. isolates. Serological assays and m-PCR were used to determine the serogroups A, B, C1, C2, D1, E, H, and FliC. The m-PCR was used to detect seven Salmonella serovars, and a Chi-square test was performed to compare the discriminatory power of the methods. Of 2300 poultry feces samples, 173 (7.5%) and 166 (7.2%) samples were detected as Salmonella spp. by cultivation and m-PCR, respectively. The sensitivity of the molecular method was equal to cultivation at 0.96 (CI = 95%). Assessment of H antigenic subgroups showed the same for both m-PCR and serological tests. Therefore, the matching rate of the two methods for detecting all H antigenic subgroups was 100%. Thus, the relationship between the results obtained from both methods was significant in the contingency table test (P < 0.01). The PCR-based approach confirmed the detection of Salmonella in a shorter period (24-36 h) compared to the conventional microbiological approach (3-8 days).
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Antimicrobial Susceptibility and Frequency of bla and qnr Genes in Salmonella enterica Isolated from Slaughtered Pigs. Antibiotics (Basel) 2021; 10:antibiotics10121442. [PMID: 34943653 PMCID: PMC8698178 DOI: 10.3390/antibiotics10121442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 12/03/2022] Open
Abstract
Salmonella enterica is known as one of the most common foodborne pathogens worldwide. While salmonellosis is usually self-limiting, severe infections may require antimicrobial therapy. However, increasing resistance of Salmonella to antimicrobials, particularly fluoroquinolones and cephalosporins, is of utmost concern. The present study aimed to investigate the antimicrobial susceptibility of S. enterica isolated from pork, the major product in Philippine livestock production. Our results show that both the qnrS and the blaTEM antimicrobial resistance genes were present in 61.2% of the isolates. While qnrA (12.9%) and qnrB (39.3%) were found less frequently, co-carriage of blaTEM and one to three qnr subtypes was observed in 45.5% of the isolates. Co-carriage of blaTEM and blaCTX-M was also observed in 3.9% of the isolates. Antimicrobial susceptibility testing revealed that the majority of isolates were non-susceptible to ampicillin and trimethoprim/sulfamethoxazole, and 13.5% of the isolates were multidrug-resistant (MDR). MDR isolates belonged to either O:3,10, O:4, or an unidentified serogroup. High numbers of S. enterica carrying antimicrobial resistance genes (ARG), specifically the presence of isolates co-carrying resistance to both β-lactams and fluoroquinolones, raise a concern on antimicrobial use in the Philippine hog industry and on possible transmission of ARG to other bacteria.
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Barmak SM, Sinyavskiy YA, Berdygaliev AB, Sharmanov TS, Savitskaya IS, Sultankulova GT, Zholdybayeva EV. Development and Evaluation of Alternative Methods to Identify the Three Most Common Serotypes of Salmonella enterica Causing Clinical Infections in Kazakhstan. Microorganisms 2021; 9:microorganisms9112319. [PMID: 34835445 PMCID: PMC8625340 DOI: 10.3390/microorganisms9112319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/29/2021] [Accepted: 11/03/2021] [Indexed: 01/22/2023] Open
Abstract
In this study, we aimed to compare the performance of conventional PCR and real-time PCR assays as screening methods for identification of three frequent, clinically significant Salmonella serovars in Kazakhstan. We determined the diagnostic efficacy of three molecular methods for detection of S. enterica subsp. enterica and typing S. Typhimurium, S. Enteritidis, and S. Virchow. A total of 137 clinical samples and 883 food samples were obtained in Almaty in 2018–2019. All tests showed high analytical specificity for detecting S. enterica and its corresponding serovariants (100%). The sensitivity of real-time PCR for each of the tested targets was 1–10 microbial cells and in conventional PCR 10–100 microbial cells. The trials with conventional PCR and real-time PCR had a diagnostic efficacy (DE) of 100% and 99.71%, respectively. The DE of real-time PCR and conventional PCR for detecting S. Enteritidis and S. Typhimurium was 99.90%, while the DE of conventional PCR and real-time PCR for detecting S. Virchow was 99.31% and 99.80%, respectively. The RAPD-PCR analysis of the genomic DNA of Salmonella enterica showed the genetic kinship of S. Enteritidis isolates, and the genetic heterogeneity of S. Typhimurium and S. Virchow isolates. Thus, the developed methods can be considered as alternatives to classical serotyping using antisera.
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Affiliation(s)
- Sabyrkhan M Barmak
- Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan
- Biotechnology and Biologically Active Substances Laboratory, Kazakh Academy of Nutrition, Almaty 050008, Kazakhstan
| | - Yuriy A Sinyavskiy
- Biotechnology and Biologically Active Substances Laboratory, Kazakh Academy of Nutrition, Almaty 050008, Kazakhstan
| | - Aidar B Berdygaliev
- Biotechnology and Biologically Active Substances Laboratory, Kazakh Academy of Nutrition, Almaty 050008, Kazakhstan
| | - Turegeldy Sh Sharmanov
- Biotechnology and Biologically Active Substances Laboratory, Kazakh Academy of Nutrition, Almaty 050008, Kazakhstan
| | - Irina S Savitskaya
- Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan
| | - Gulmira T Sultankulova
- Department of Pediatric Surgery, Asfendiyarov Kazakh National Medical University, Almaty 050012, Kazakhstan
| | - Elena V Zholdybayeva
- National Center for Biotechnology, National Scientific Shared Laboratory of Biotechnology, Nur-Sultan 010000, Kazakhstan
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7
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Xin S, Zhu H, Tao C, Zhang B, Yao L, Zhang Y, Afayibo DJA, Li T, Tian M, Qi J, Ding C, Yu S, Wang S. Rapid Detection and Differentiating of the Predominant Salmonella Serovars in Chicken Farm by TaqMan Multiplex Real-Time PCR Assay. Front Cell Infect Microbiol 2021; 11:759965. [PMID: 34660351 PMCID: PMC8512842 DOI: 10.3389/fcimb.2021.759965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 09/10/2021] [Indexed: 01/27/2023] Open
Abstract
Salmonella has been known as an important zoonotic pathogen that can cause a variety of diseases in both animals and humans. Poultry are the main reservoir for the Salmonella serovars Salmonella Pullorum (S. Pullorum), Salmonella Gallinarum (S. Gallinarum), Salmonella Enteritidis (S. Enteritidis), and Salmonella Typhimurium (S. Typhimurium). The conventional serotyping methods for differentiating Salmonella serovars are complicated, time-consuming, laborious, and expensive; therefore, rapid and accurate molecular diagnostic methods are needed for effective detection and prevention of contamination. This study developed and evaluated a TaqMan multiplex real-time PCR assay for simultaneous detection and differentiation of the S. Pullorum, S. Gallinarum, S. Enteritidis, and S. Typhimurium. In results, the optimized multiplex real-time PCR assay was highly specific and reliable for all four target genes. The analytical sensitivity corresponded to three colony-forming units (CFUs) for these four Salmonella serovars, respectively. The detection limit for the multiplex real-time PCR assay in artificially contaminated samples was 500 CFU/g without enrichment, while 10 CFU/g after pre-enrichment. Moreover, the multiplex real-time PCR was applied to the poultry clinical samples, which achieved comparable results to the traditional bacteriological examination. Taken together, these results indicated that the optimized TaqMan multiplex real-time PCR assay will be a promising tool for clinical diagnostics and epidemiologic study of Salmonella in chicken farm and poultry products.
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Affiliation(s)
- Suhua Xin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Hong Zhu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Chenglin Tao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Beibei Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Lan Yao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yaodong Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | | | - Tao Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Jingjing Qi
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
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8
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Gong Y, Li J, Zhu D, Wang S, Xu Y, Li Y, Wang Y, Song Y, Liu W, Tian Y. Case Report: Near-Fatal Intestinal Hemorrhage and Acute Acalculous Cholecystitis due to Vi-Negative and Fluoroquinolone-Insensitive Salmonella enterica Serovar Typhi Infection: A Rare Entity. Front Med (Lausanne) 2021; 8:666643. [PMID: 34447758 PMCID: PMC8383206 DOI: 10.3389/fmed.2021.666643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/14/2021] [Indexed: 11/13/2022] Open
Abstract
Typhoid fever is usually a mild clinical disease. Typhoid fever with massive intestinal hemorrhage is rare in the antibiotic era. Acute acalculous cholecystitis (AAC) is also rare in adults. Here, we describe the first adult case of typhoid fever with both complications due to Vi-negative and fluoroquinolone-insensitive Salmonella enterica serovar Typhi (S. Typhi) infection. We aim to alert physicians to this rare condition.
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Affiliation(s)
- Yuehua Gong
- Yantai Center for Disease Control and Prevention, Yantai, China
| | - Jianlin Li
- Department of Radiology, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
| | - Dongnan Zhu
- Yantai Center for Disease Control and Prevention, Yantai, China
| | - Songsong Wang
- Yantai Center for Disease Control and Prevention, Yantai, China
| | - Yingchun Xu
- Yantai Center for Disease Control and Prevention, Yantai, China
| | - Yan Li
- Yantai Center for Disease Control and Prevention, Yantai, China
| | - Yanqing Wang
- Yantai Center for Disease Control and Prevention, Yantai, China
| | - Yan Song
- Yantai Center for Disease Control and Prevention, Yantai, China
| | - Wenjuan Liu
- Yantai Center for Disease Control and Prevention, Yantai, China
| | - Yunlong Tian
- Yantai Center for Disease Control and Prevention, Yantai, China
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Yasin N, Rahman H, Sarwar Y, Qasim M, Nisa I, Ikram A, Zaman G, Khan Z, Mirza MR, Khan N, Safi AUR, Alzahrani KJ. Salmonella Typhi from Northwest Pakistan: Molecular Strain Typing and Drug Resistance Signature. Microb Drug Resist 2021; 28:120-126. [PMID: 34357814 DOI: 10.1089/mdr.2020.0304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Objective: To determine the molecular strain typing and drug resistance pattern of Salmonella enterica serovar Typhi prevalent in Northwest Pakistan. Methodology: A total of 2,138 blood samples of suspected typhoid patients from Northwest Pakistan were collected followed by identification of Salmonella Typhi through biochemical, serological, and species-specific fliC-d gene amplification. These isolates were typed by variable-number tandem repeat (VNTR) profiling and investigated for drug resistance. Results: The overall prevalence of Salmonella Typhi was found to be 8.8% (n = 189). Thirty different VNTR strain types of Salmonella Typhi were detected and the most prevalent strain types were T1 and T4, whereas T27 was less prevalent strain. Among the 189 isolates 175 (92.5%) isolates were multidrug resistant, whereas 12 (5.8%) isolates were extensively drug resistant. Resistance to imipenem in Salmonella Typhi was not observed. Most of the isolates have genes encoding for resistance to fluoroquinolones, including gyrA (n = 164), gyrB (n = 160), parC (n = 164), parE (n = 160), ac(6')-ib-cr (n = 163), qnrS (n = 15), and qnrB (n = 3). Similarly, chloramphinicol (cat; n = 147), azithromycin (msrA; n = 3), and co-trimoxazole (dfrA7; n = 145) resistance genes were detected among Salmonella Typhi isolates. Conclusion: In this study, T1 and T4 type Salmonella Typhi strains were predominantly prevalent in Northwest Pakistan. Antibiotic resistance among Salmonella Typhi isolates were observed. Findings of the study would be helpful to devise an appropriate antibiotic policy to control the emergence of drug-resistant Salmonella Typhi in Pakistan.
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Affiliation(s)
- Nusrat Yasin
- Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan
| | - Hazir Rahman
- Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan.,Department of Microbiology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Yasra Sarwar
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
| | - Muhammad Qasim
- Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan
| | - Iqbal Nisa
- Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan
| | - Aamer Ikram
- Department of Pathology, Armed Forces Institute of Pathology, CMH, Rawalpindi, Pakistan.,National Institute of Health, Islamabad, Pakistan
| | - Gohar Zaman
- Department of Pathology, Armed Forces Institute of Pathology, CMH, Rawalpindi, Pakistan
| | - Zakir Khan
- Institute of Health Sciences, Curkvoa University Adana, Adana, Turkey
| | - Munazza Raza Mirza
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Niamat Khan
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology, Kohat, Pakistan
| | - Aziz-Ur-Rehman Safi
- Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan
| | - Khalid J Alzahrani
- Department of Clinical Laboratories Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
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10
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Cordovana M, Mauder N, Kostrzewa M, Wille A, Rojak S, Hagen RM, Ambretti S, Pongolini S, Soliani L, Justesen US, Holt HM, Join-Lambert O, Le Hello S, Auzou M, Veloo AC, May J, Frickmann H, Dekker D. Classification of Salmonella enterica of the (Para-)Typhoid Fever Group by Fourier-Transform Infrared (FTIR) Spectroscopy. Microorganisms 2021; 9:microorganisms9040853. [PMID: 33921159 PMCID: PMC8071548 DOI: 10.3390/microorganisms9040853] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 12/31/2022] Open
Abstract
Typhoidal and para-typhoidal Salmonella are major causes of bacteraemia in resource-limited countries. Diagnostic alternatives to laborious and resource-demanding serotyping are essential. Fourier transform infrared spectroscopy (FTIRS) is a rapidly developing and simple bacterial typing technology. In this study, we assessed the discriminatory power of the FTIRS-based IR Biotyper (Bruker Daltonik GmbH, Bremen, Germany), for the rapid and reliable identification of biochemically confirmed typhoid and paratyphoid fever-associated Salmonella isolates. In total, 359 isolates, comprising 30 S. Typhi, 23 S. Paratyphi A, 23 S. Paratyphi B, and 7 S. Paratyphi C, respectively and other phylogenetically closely related Salmonella serovars belonging to the serogroups O:2, O:4, O:7 and O:9 were tested. The strains were derived from clinical, environmental and food samples collected at different European sites. Applying artificial neural networks, specific automated classifiers were built to discriminate typhoidal serovars from non-typhoidal serovars within each of the four serogroups. The accuracy of the classifiers was 99.9%, 87.0%, 99.5% and 99.0% for Salmonella Typhi, Salmonella Paratyphi A, B and Salmonella Paratyphi C, respectively. The IR Biotyper is a promising tool for fast and reliable detection of typhoidal Salmonella. Hence, IR biotyping may serve as a suitable alternative to conventional approaches for surveillance and diagnostic purposes.
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Affiliation(s)
- Miriam Cordovana
- Bruker Daltonik GmbH, 28359 Bremen, Germany; (M.C.); (N.M.); (M.K.)
| | - Norman Mauder
- Bruker Daltonik GmbH, 28359 Bremen, Germany; (M.C.); (N.M.); (M.K.)
| | - Markus Kostrzewa
- Bruker Daltonik GmbH, 28359 Bremen, Germany; (M.C.); (N.M.); (M.K.)
| | - Andreas Wille
- Institute for Hygiene and Environment, 20539 Hamburg, Germany;
| | - Sandra Rojak
- Department of Microbiology and Hospital Hygiene, Bundeswehr Central Hospital Koblenz, 56070 Koblenz, Germany; (S.R.); (R.M.H.)
| | - Ralf Matthias Hagen
- Department of Microbiology and Hospital Hygiene, Bundeswehr Central Hospital Koblenz, 56070 Koblenz, Germany; (S.R.); (R.M.H.)
| | - Simone Ambretti
- Operative Unit of Microbiology, IRCCS-Azienda Ospedaliero Policlinico Sant’Orsola-Universitaria di Bologna, 40138 Bologna, Italy;
| | - Stefano Pongolini
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale Della Lombardia e dell’Emilia-Romagna, 43126 Parma, Italy; (S.P.); (L.S.)
| | - Laura Soliani
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale Della Lombardia e dell’Emilia-Romagna, 43126 Parma, Italy; (S.P.); (L.S.)
| | - Ulrik S. Justesen
- Department of Clinical Microbiology, Odense University Hospital, 5000 Odense C, Denmark; (U.S.J.); (H.M.H.)
| | - Hanne M. Holt
- Department of Clinical Microbiology, Odense University Hospital, 5000 Odense C, Denmark; (U.S.J.); (H.M.H.)
| | - Olivier Join-Lambert
- Department of Microbiology, Université de Caen, Normandie, CEDEX 5, 14032 Caen, France; (O.J.-L.); (S.L.H.); (M.A.)
| | - Simon Le Hello
- Department of Microbiology, Université de Caen, Normandie, CEDEX 5, 14032 Caen, France; (O.J.-L.); (S.L.H.); (M.A.)
| | - Michel Auzou
- Department of Microbiology, Université de Caen, Normandie, CEDEX 5, 14032 Caen, France; (O.J.-L.); (S.L.H.); (M.A.)
| | - Alida C. Veloo
- University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, University of Groningen, 9700 AB Groningen, The Netherlands;
| | - Jürgen May
- Infectious Disease Department, Bernhard Nocht Institute for Tropical Medicine Hamburg, 20359 Hamburg, Germany; or
- University Medical Center Hamburg-Eppendorf (UKE), Tropical Medicine II Hamburg, 20359 Hamburg, Germany
| | - Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, 20359 Hamburg, Germany; or
- Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, 18057 Rostock, Germany
| | - Denise Dekker
- Infectious Disease Department, Bernhard Nocht Institute for Tropical Medicine Hamburg, 20359 Hamburg, Germany; or
- German Centre for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, 38124 Braunschweig, Germany
- Correspondence:
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11
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Nucleic Acid-Based Lateral Flow Biosensor for Salmonella Typhi and Salmonella Paratyphi: A Detection in Stool Samples of Suspected Carriers. Diagnostics (Basel) 2021; 11:diagnostics11040700. [PMID: 33919817 PMCID: PMC8070779 DOI: 10.3390/diagnostics11040700] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/11/2021] [Accepted: 04/11/2021] [Indexed: 11/17/2022] Open
Abstract
A multiplex rapid detection system, based on a PCR-lateral flow biosensor (mPCR-LFB) was developed to identify Salmonella Typhi and Salmonella Paratyphi A from suspected carriers. The lower detection limit for S. Typhi and S. Paratyphi A was 0.16 and 0.08 ng DNA equivalent to 10 and 102 CFU/mL, respectively. Lateral flow biosensor was used for visual detection of mPCR amplicons (stgA, SPAint, ompC, internal amplification control) by labeling forward primers with fluorescein-isothiocyanate (FITC), Texas Red, dinitrophenol (DNP) and digoxigenin (DIG) and reverse primers with biotin. Binding of streptavidin-colloidal gold conjugate with the amplicons resulted in formation of a red color dots on the strip after 15-20 min of sample exposure. The nucleic acid lateral flow analysis of the mPCR-LFB was better in sensitivity and more rapid than the conventional agarose gel electrophoresis. Moreover, the mPCR-LFB showed 100% sensitivity and specificity when evaluated with stools spiked with 100 isolates of Salmonella genus and other bacteria. A prospective cohort study on stool samples of 1176 food handlers in outbreak areas (suspected carriers) resulted in 23 (2%) positive for S. Typhi. The developed assay has potential to be used for rapid detection of typhoid carriers in surveillance program.
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12
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Teh CSJ, Lau MY, Chong CW, Ngoi ST, Chua KH, Lee WS, Thong KL. One-step differential detection of Salmonella enterica serovar Typhi, serovar Paratyphi A and other Salmonella spp. by using a quadruplex real-time PCR assay. J Microbiol Methods 2021; 183:106184. [PMID: 33662480 DOI: 10.1016/j.mimet.2021.106184] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/14/2022]
Abstract
Diseases caused by typhoidal and non-typhoidal Salmonella remain a considerable threat to both developed and developing countries. Based on the clinical symptoms and serological tests, it is sometimes difficult to differentiate the Salmonella enterica serovar Paratyphi A (S. enterica serovar Paratyphi A) from serovar Typhi (S. enterica serovar Typhi). In this study, we developed a quadruplex real-time polymerase chain reaction (PCR) assay with an internal amplification control (IAC), to simultaneously differentiate S. enterica serovar Paratyphi A from serovar Typhi and to detect other Salmonella serovars which cause salmonellosis in humans. This assay was evaluated on 155 salmonellae and non-salmonellae strains and demonstrated 100% specificity in species differentiation. Inclusion of an IAC did not affect the efficiency of the assay. Further evaluation using a blind test on spiked stool, blood and food specimens showed that the detection limit was at 103 -104 CFU/mL (or g) and a high PCR efficiency with different targets (R2 > 0.99), except for S. enterica serovar Paratyphi A in blood. This assay has been applied to clinical specimens to detect the causative agents of gastrointestinal infections and has successfully identified 6 salmonellosis patients from the 50 diarrhoea patients. The quadruplex real-time PCR developed in this study could enhance the detection and differentiation of salmonellae. This assay could be applied to stools, blood and food based on the notable performance in the simulation tests and field evaluation.
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Affiliation(s)
- Cindy Shuan Ju Teh
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Min Yi Lau
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Chun Wie Chong
- School of Pharmacy, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia
| | - Soo Tein Ngoi
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kek Heng Chua
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Way Seah Lee
- Department of Paediatrics, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kwai Lin Thong
- Nanotechnology & Catalysis Research Centre, Deputy Vice Chancellor (Research & Innovation), University of Malaya, 50603 Kuala Lumpur, Malaysia
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13
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Zhao L, Wang J, Sun XX, Wang J, Chen Z, Xu X, Dong M, Guo YN, Wang Y, Chen P, Gao W, Geng Y. Development and Evaluation of the Rapid and Sensitive RPA Assays for Specific Detection of Salmonella spp. in Food Samples. Front Cell Infect Microbiol 2021; 11:631921. [PMID: 33718280 PMCID: PMC7946851 DOI: 10.3389/fcimb.2021.631921] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 01/19/2021] [Indexed: 11/16/2022] Open
Abstract
Salmonella spp. is among the main foodborne pathogens which cause serious foodborne diseases. An isothermal real-time recombinase polymerase amplification (RPA) and lateral flow strip detection (LFS RPA) were used to detect Salmonella spp. targeting the conserved sequence of invasion protein A (invA). The Real-time RPA was performed in a portable florescence scanner at 39°C for 20 min. The LFS RPA was performed in an incubator block at 39°C for 15 min, under the same condition that the amplifications could be inspected by the naked eyes on the LFS within 5 min. The detection limit of Salmonella spp. DNA using real-time RPA was 1.1 × 101 fg, which was the same with real-time PCR but 10 times higher than that of LFS RPA assay. Moreover, the practicality of discovering Salmonella spp. was validated with artificially contaminated lamb, chicken, and broccoli samples. The analyzing time dropped from 60 min to proximately 5–12 min on the basis of the real-time and LFS RPA assays compared with the real-time PCR assay. Real-time and LFS RPA assays’ results were equally reliable. There was no cross-reactivity with other pathogens in both assays. In addition, the assays had good stability. All of these helped to show that the developed RPA assays were simple, rapid, sensitive, credible, and could be a potential point-of-need (PON) test required mere resources.
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Affiliation(s)
- Liwei Zhao
- Heibei Key Laboratory of Chinese Medicine Research on Cardiocerebrovascular Disease, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Jianchang Wang
- Food Microbiology and Animal Quarantine Laboratory, Technology Center of Shijiazhuang Customs, Shijiazhuang, China
| | - Xiao Xia Sun
- Food Microbiology and Animal Quarantine Laboratory, Technology Center of Shijiazhuang Customs, Shijiazhuang, China
| | - Jinfeng Wang
- Food Microbiology and Animal Quarantine Laboratory, Technology Center of Shijiazhuang Customs, Shijiazhuang, China
| | - Zhimin Chen
- Food Microbiology and Animal Quarantine Laboratory, Technology Center of Shijiazhuang Customs, Shijiazhuang, China
| | - Xiangdong Xu
- School of Public Health, Key Laboratory of Environment and Human Health, Hebei Medical University, Shijiazhuang, China
| | - Mengyuan Dong
- Heibei Key Laboratory of Chinese Medicine Research on Cardiocerebrovascular Disease, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Ya-Nan Guo
- Heibei Key Laboratory of Chinese Medicine Research on Cardiocerebrovascular Disease, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Yuanyuan Wang
- Heibei Key Laboratory of Chinese Medicine Research on Cardiocerebrovascular Disease, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Pingping Chen
- Heibei Key Laboratory of Chinese Medicine Research on Cardiocerebrovascular Disease, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Weijuan Gao
- Heibei Key Laboratory of Chinese Medicine Research on Cardiocerebrovascular Disease, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Yunyun Geng
- Heibei Key Laboratory of Chinese Medicine Research on Cardiocerebrovascular Disease, Hebei University of Chinese Medicine, Shijiazhuang, China
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14
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Rapid detection of flagellated and non-flagellated Salmonella by targeting the common flagellar hook gene flgE. Appl Microbiol Biotechnol 2020; 104:9719-9732. [PMID: 33009938 DOI: 10.1007/s00253-020-10925-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/10/2020] [Accepted: 09/21/2020] [Indexed: 01/06/2023]
Abstract
Salmonella spp. can cause animal and human salmonellosis. In this study, we established a simple method to detect all Salmonella species by amplifying a specific region within the flgE gene encoding the flagellar hook protein. Our preliminary sequence analysis among flagella-associated genes of Salmonella revealed that although Salmonella Gallinarum and Salmonella Pullorum are lacking flagella, they did have flagella-associated genes, including flgE. To investigate in detail, a comparative flgE sequence analysis was conducted using different bacterial strains including flagellated and non-flagellated Salmonella as well as non-Salmonella strains. Two unique regions (481-529 bp and 721-775 bp of the reference sequence) within the flgE open reading frame were found to be highly conserved and specific to all Salmonella species. Next, we designed a pair of PCR primers (flgE-UP and flgE-LO) targeting the above two regions, and performed a flgE-tailored PCR using as template DNA prepared from a total of 76 bacterial strains (31 flagellated Salmonella strains, 26 non-flagellated Salmonella strains, and 19 other non-Salmonella bacteria strains). Results showed that specific positive bands with expected size were obtained from all Salmonella (including flagellated and non-flagellated Salmonella) strains, while no specific product was generated from non-Salmonella bacterial strains. PCR products from the positive bands were confirmed by DNA sequencing. The minimum detection amount for genomic DNA and bacteria cells reached 18.3 pg/μL and 100 colony-forming unit (CFU) per PCR reaction, respectively. Using the flgE-PCR method to detect Salmonella in artificially contaminated milk samples, as low as 1 CFU/mL Salmonella was detectable after an 8-h pre-culture. Meanwhile, the flgE-tailored PCR method was applied to evaluate 247 clinical samples infected with Salmonella from different chicken breeding farms. The detection results indicated that flgE-PCR could be used to specifically detect Salmonella in concordance with the traditional bacterial culture-based detection method. It is worthwhile noticed that identification results using flgE-tailored PCR should be completed within less than 1 day, expanding the result of much faster than the standard method, which took more than 5 days. Overall, the flgE-tailored PCR method can specifically detect flagellated and non-flagellated Salmonella and can serve as a powerful tool for rapid, simple, and sensitive detection of Salmonella species. KEY POINTS : • Targeting flgE gene for all Salmonella spp. found. • The established PCR assay is used to specifically detect all Salmonella spp. • The PCR method is applied to detect clinical Salmonella spp. samples within less than 1 day.
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15
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Santos PDM, Widmer KW, Rivera WL. PCR-based detection and serovar identification of Salmonella in retail meat collected from wet markets in Metro Manila, Philippines. PLoS One 2020; 15:e0239457. [PMID: 32997676 PMCID: PMC7526908 DOI: 10.1371/journal.pone.0239457] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 09/08/2020] [Indexed: 11/27/2022] Open
Abstract
This study aimed to detect Salmonella from retail meat collected from nine wet markets in Metro Manila, and identify the subtypes of Salmonella isolates using molecular serotyping assays from previously developed primers. Of the 720 collected meat samples, 57.64% were found to be Salmonella-contaminated. The most predominant serogroup was Salmonella O:3, and Salmonella serogroups O:4, O:6,7, O:8, O:9, and undetermined serogroups were also found. Most frequently detected isolates in bovine meat were S. 3:e,h:1,6 (putative identity: S. Anatum) and S: 4:e,h:1,2 (putative identity: S. Saintpaul), in porcine meat was S. 3:e,h:1,6 (putative identity: S. Anatum), and S. 8:i:z6 (putative identity: S. Kentucky) was common in poultry products. This study also demonstrated retail meat samples were contaminated with multiple Salmonella serogroups and serovars. This is the first Philippine study that utilized PCR-based assays to characterize Salmonella isolates down to a serovar level and provides baseline information regarding Salmonella prevalence and serovar distribution in retail meat. Molecular serotyping performed in this study can be used as an alternative approach to traditional serotyping in surveillance of Salmonella in the Philippines since the latter is expensive, time-consuming, and requires skilled technicians.
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Affiliation(s)
- Pauline Dianne M. Santos
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City, Philippines
| | - Kenneth W. Widmer
- International Environmental Research Institute, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Windell L. Rivera
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City, Philippines
- * E-mail:
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16
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Kasturi KN. A real-time PCR for rapid identification of Salmonella enterica Gaminara serovar. J Microbiol Methods 2019; 169:105729. [PMID: 31711901 DOI: 10.1016/j.mimet.2019.105729] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/13/2019] [Accepted: 09/21/2019] [Indexed: 12/17/2022]
Abstract
Salmonella is one of the leading causes of foodborne illnesses in the USA. When a Salmonella outbreak occurs, rapid identification of the causative serovar is important for tracing the source of contamination and for preventing the further spread of the illness. Each serovar is characterized by the presence of a group-specific somatic O-antigen(s) and an assortment of flagellar phase-1 and phase-2 antigens. As the traditional serotyping protocol is time consuming, labor intensive, and expensive, faster and less expensive molecular diagnostic methods are needed. This report outlines the development of a rapid multiplex real-time PCR procedure that facilitates the identification of Salmonella serogroup I and the serovars of the group. Using Salmonella Gaminara serovar (O16:d:1,7) as an example, first the gene(s) responsible for expression of the somatic O antigen, O16, and the nucleotide sequence of the variable-region of genes encoding the flagellar phase-1 (d) and phase-2 (1,7) antigens were identified. Then, a multiplex real-time PCR was designed that incorporated primers and probes specific for the three target genes and confirmed the specificity. The assay had 100% inclusivity for all three gene targets, detecting 2 genomic DNA copies of O16 and 1,7 gene targets and 10 copies of d gene target. Importance: Rapid molecular methods to identify Salmonella serovars should increase the precision of routine surveillance of clinically important serovars and promote public health.
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Affiliation(s)
- Kuppuswamy N Kasturi
- U. S. Food and Drug Administration, Office of Regulatory Affairs, Office of Regulatory Science, Northeast Food and Feed Laboratory, Jamaica, New York 11433, USA.
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17
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Real-Time PCR Assay for Differentiation of Typhoidal and Nontyphoidal Salmonella. J Clin Microbiol 2019; 57:JCM.00167-19. [PMID: 31167843 DOI: 10.1128/jcm.00167-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/30/2019] [Indexed: 01/01/2023] Open
Abstract
Rapid and accurate differentiation of Salmonella spp. causing enteric fever from nontyphoidal Salmonella is essential for clinical management of cases, laboratory risk management, and implementation of public health measures. Current methods used for confirmation of identification, including biochemistry and serotyping as well as whole-genome sequencing analyses, take several days. Here we report the development and evaluation of a real-time PCR assay that can be performed directly on crude DNA extracts from bacterial colonies for the rapid identification of typhoidal and nontyphoidal Salmonella.
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18
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Rojak S, Wiemer DF, Wille A, Loderstädt U, Wassill L, Hinz R, Hagen RM, Frickmann H. Loop-mediated isothermal amplification for paratyphoid fever - a proof-of-principle analysis. Lett Appl Microbiol 2019; 68:509-513. [PMID: 30761564 DOI: 10.1111/lam.13130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 11/26/2022]
Abstract
In-house loop-mediated isothermal amplification (LAMP) procedures for the detection of paratyphoid fever-associated bacteria on serovar level were evaluated. Therefore, LAMP primers for Salmonella genus, for two LAMP schemes for S. Paratyphi A, for S. Paratyphi B and for S. Paratyphi C were tested with DNA from culture isolates from strain collections and spiked blood cultures against published PCR protocols targeting the same micro-organisms. Sensitivity and specificity for DNA from culture isolates verified by LAMP ranged from 80·0 to 100·0% and 96·1 to 100·0% vs 65 to 100% and 98·7 to 100% for the PCR approaches. For the spiked blood culture materials, sensitivity and specificity for LAMP ranged from 87·5 to 100·0% and 96·7 to 100·0% vs from 60 to 100% and 98·2 to 100% for PCR. In conclusion, LAMP for paratyphoid fever shows comparable performance characteristics as PCR. Due to its easy application, the procedure is well suited for surveillance purposes in resource-limited settings. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of easy-to-apply, point-of-care-testing-like loop-mediated isothermal amplification (LAMP) for the diagnosis of paratyphoid fever is evaluated. This approach can contribute to low-threshold availability of surveillance options for resource limited settings. Easy-to-teach and easy-to-apply LAMP schemes with similar performance characteristics as PCR are provided. The described test evaluation is of particular use for surveillance and public health experts.
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Affiliation(s)
- S Rojak
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany.,Department of Infectious Diseases and Tropical Medicine, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - D F Wiemer
- Department of Infectious Diseases and Tropical Medicine, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - A Wille
- Institute for Hygiene and Environment, City of Hamburg, Hamburg, Germany
| | - U Loderstädt
- Institute for Hygiene and Environment, City of Hamburg, Hamburg, Germany
| | - L Wassill
- Amplex Diagnostics GmbH, Gars-Bahnhof, Germany
| | - R Hinz
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - R M Hagen
- Department of Preventive Medicine, Bundeswehr Medical Academy, Munich, Germany
| | - H Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany.,Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
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19
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Development of a novel S. Typhi and Paratyphi A outer membrane vesicles based bivalent vaccine against enteric fever. PLoS One 2018; 13:e0203631. [PMID: 30216367 PMCID: PMC6138408 DOI: 10.1371/journal.pone.0203631] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 08/23/2018] [Indexed: 01/07/2023] Open
Abstract
Salmonella Typhi and Salmonella Paratyphi A are the leading causative agents of enteric fever which cause morbidity and mortality worldwide. Currently, there is no combination vaccine which could protect infection from both the strains. In this paper, we are focusing on the development of a novel bivalent typhoidal Outer Membrane Vesicles (OMVs) based immunogen against enteric fever. We have isolated Salmonella Typhi and Paratyphi A OMVs and also characterized OMVs associated antigens. Then we immunized adult mice with three doses of our newly formulated bivalent immunogen orally (25 μg/200 μl). After three doses of oral immunization, we found our immunogen could significantly induce humoral response. We have also found serum IgG against LPS, Vi-polysaccharide etc. OMV immunization induces CD4, CD8 and CD19 population in immunized mice spleen. It also induces Th1 and Th17-cell mediated immunity. We also found bivalent OMVs immunization can prevent more than lethal dose of heterologous Salmonella strains mediated systemic infection in adult mice model. We determined that, the protective immune responses depend on the humoral and cell-mediated immune response. Furthermore, we have evaluated the mode of protective immune response carried out by anti-OMVs antibody by significantly inhibiting bacterial motility and mucin penetration ability. Taken together, these findings suggest that our bivalent immunogen could be used as a novel candidate vaccine against enteric fever.
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20
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Zhang P, Zhuang L, Zhang D, Xu J, Dou X, Wang C, Gong J. Serovar-Specific Polymerase Chain Reaction for Detection of Salmonella enterica Serovar Indiana. Foodborne Pathog Dis 2018; 15:776-781. [PMID: 30183348 DOI: 10.1089/fpd.2018.2492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Salmonella enterica serovar Indiana (S. Indiana) is a newly emerging pathogen with high levels of drug resistance. It has become one of the most common Salmonella serovars in China with a worldwide distribution, posing significant public health concerns. Detection of S. Indiana by traditional bacteriological methods is time-consuming and laborious, which prevents timely surveillance and effective control of the pathogen. In this study, comparative genomics was used to identify an A7P63_13850 gene that is uniquely present in S. Indiana, but not in other Salmonella serovars or any non-Salmonella bacteria. Then, a polymerase chain reaction (PCR) assay targeting this serovar-specific gene was established for specific detection of S. Indiana. The detection limit of this method is 10 pg per reaction for bacterial genomic DNA, being equivalent to 100 colony-forming units (CFU) per reaction. The established PCR amplifies all S. Indiana strains (n = 56), but none of other Salmonella serovars (n = 146) and non-Salmonella species (n = 14). The assay established in this study was also used to detect clinical samples from poultry, showed a positivity of 14.7% (23/156) for S. Indiana, which were verified by bacteriological methods. The highly sensitive and serovar-specific PCR for S. Indiana established in this study is suitable and convenient for detection of S. Indiana which aids in surveillance and control of the pathogen.
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Affiliation(s)
- Ping Zhang
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, China
| | - Linlin Zhuang
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Di Zhang
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, China
| | - Jingxiao Xu
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou, China
| | - Xinhong Dou
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, China
| | - Chengming Wang
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Jiansen Gong
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, China
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21
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Woh PY, Thong KL, Behnke JM, Lewis JW, Zain SNM. Characterization of Nontyphoidal Salmonella Isolates from Asymptomatic Migrant Food Handlers in Peninsular Malaysia. J Food Prot 2017; 80:1378-1383. [PMID: 28722485 DOI: 10.4315/0362-028x.jfp-16-342] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Asymptomatic Salmonella carriers who work as food handlers pose food safety and public health risks, particularly during food preparation, and this has serious implications for the disease burden in society. Therefore, we conducted a study to determine the number of Salmonella carriers in a migrant cohort in several food establishments in three major cities in Peninsular Malaysia. Sociodemographic data and stool samples were collected and analyzed using standard methods of detection and isolation. Antimicrobial susceptibility tests of the positive samples were also performed. A total of 317 migrant food handlers, originating from South and Southeast Asian countries, were recruited voluntarily. Nine (2.8%) stool samples were confirmed to be Salmonella positive. PCR serotyping and pulsed-field gel electrophoresis identified four serotypes as Typhimurium (n = 3), Corvallis (n = 2), Hadar (n = 1), Agona (n = 1) and two unknown serovars. Antimicrobial susceptibility tests revealed that all nine isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, ceftazidime, ceftriaxone, and gentamycin. However, seven isolates were found to be multidrug resistant to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, sulfonamides, streptomycin, and tetracycline. This study highlights that carriers of nontyphoidal Salmonella exist among migrant food handlers, which poses a health risk to consumers through food contamination. Our results indicate a need for authorities to enhance food safety awareness in the migrant workers and to reevaluate current health screening methods to include preventive measure such as mandatory stool screening as part of the preemployment and routine health examinations.
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Affiliation(s)
- Pei Yee Woh
- 1 Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kwai Lin Thong
- 1 Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | | | - John Watkin Lewis
- 3 School of Biological Sciences, Royal Holloway University of London, Egham TW20 OEX, UK
| | - Siti Nursheena Mohd Zain
- 1 Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
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22
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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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Purification and antigenic detection of O-specific polysaccharides of Salmonella enterica serovar Paratyphi A isolate from Pakistan: an emerging threat. SPRINGERPLUS 2016; 5:1954. [PMID: 27933236 PMCID: PMC5104697 DOI: 10.1186/s40064-016-3643-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 11/03/2016] [Indexed: 11/10/2022]
Abstract
BACKGROUND Paratyphoid fever caused by Salmonella enterica serovar Paratyphi A is becoming a serious health problem in Asian countries particularly Pakistan, China and India and situation is aggravated by current unavailability of a licensed vaccine. This study was designed to purify the O-specific polysaccharides (OSP) produced by an isolate of Salmonella Paratyphi A from Pakistan and detect antigenicity of extracted lipopolysaccharide (LPS) and purified OSP pioneerly in South Asian region as candidate for conjugate vaccine preparation. RESULTS S. Paratyphi A isolates were identified through PCR using primers of fliC-a gene (329 bp) and confirmed via nested PCR using fliC-nested primers (289 bp). Yield of the LPS of S. Paratyphi A isolate was 40 mg/L of the bacterial culture using hot phenol method. The purified LPS revealed the characteristic ladder like pattern of S. Paratyphi A LPS on SDS-PAGE with silver staining. Purified OSP obtained by acid hydrolysis yielded 23 mg/L of culture broth and was not detected by silver staining. Antigenic interaction of the purified LPS and OSP with hyper immune mice sera was confirmed by single precipitin line evaluated through immunodiffusion assay. The antigenicity was found well intact. CONCLUSIONS The purified antigenic OSP from S. Paratyphi A may have the potential to be coupled with a carrier protein to develop low cost conjugate vaccine candidates against S. Paratyphi A in paratyphoid endemic regions.
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Identification of Five Novel Salmonella Typhi-Specific Genes as Markers for Diagnosis of Typhoid Fever Using Single-Gene Target PCR Assays. BIOMED RESEARCH INTERNATIONAL 2016; 2016:8905675. [PMID: 27975062 PMCID: PMC5126401 DOI: 10.1155/2016/8905675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/27/2016] [Accepted: 10/18/2016] [Indexed: 12/21/2022]
Abstract
Salmonella Typhi (S. Typhi) causes typhoid fever which is a disease characterised by high mortality and morbidity worldwide. In order to curtail the transmission of this highly infectious disease, identification of new markers that can detect the pathogen is needed for development of sensitive and specific diagnostic tests. In this study, genomic comparison of S. Typhi with other enteric pathogens was performed, and 6 S. Typhi genes, that is, STY0201, STY0307, STY0322, STY0326, STY2020, and STY2021, were found to be specific in silico. Six PCR assays each targeting a unique gene were developed to test the specificity of these genes in vitro. The diagnostic sensitivities and specificities of each assay were determined using 39 S. Typhi, 62 non-Typhi Salmonella, and 10 non-Salmonella clinical isolates. The results showed that 5 of these genes, that is, STY0307, STY0322, STY0326, STY2020, and STY2021, demonstrated 100% sensitivity (39/39) and 100% specificity (0/72). The detection limit of the 5 PCR assays was 32 pg for STY0322, 6.4 pg for STY0326, STY2020, and STY2021, and 1.28 pg for STY0307. In conclusion, 5 PCR assays using STY0307, STY0322, STY0326, STY2020, and STY2021 were developed and found to be highly specific at single-gene target resolution for diagnosis of typhoid fever.
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Ng KCS, Rivera WL. Multiplex PCR-Based Serogrouping and Serotyping of Salmonella enterica from Tonsil and Jejunum with Jejunal Lymph Nodes of Slaughtered Swine in Metro Manila, Philippines. J Food Prot 2015; 78:873-80. [PMID: 25951380 DOI: 10.4315/0362-028x.jfp-14-342] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Food poisoning outbreaks and livestock mortalities caused by Salmonella enterica are widespread in the Philippines, with hogs being the most commonly recognized carriers of the pathogen. To prevent and control the occurrence of S. enterica infection in the country, methods were used in this study to isolate and rapidly detect, differentiate, and characterize S. enterica in tonsils and jejuna with jejunal lymph nodes of swine slaughtered in four locally registered meat establishments (LRMEs) and four meat establishments accredited by the National Meat Inspection Services in Metro Manila. A total of 480 samples were collected from 240 animals (120 pigs from each type of meat establishment). A significantly higher proportion of pigs were positive for S. enterica in LRMEs (60 of 120) compared with meat establishments accredited by the National Meat Inspection Services (38 of 120). More S. enterica-positive samples were found in tonsils compared with jejuna with jejunal lymph nodes in LRMEs, but this difference was not significant. A PCR assay targeting the invA gene had sensitivity that was statistically similar to that of the culture method, detecting 93 of 98 culture-confirmed samples. Multiplex PCR-based O-serogrouping and H/Sdf I typing revealed four S. enterica serogroups (B, C1, D, and E) and six serotypes (Agona, Choleraesuis, Enteritidis, Heidelberg, Typhimurium, and Weltevreden), respectively, which was confirmed by DNA sequencing of the PCR products. This study was the first to report detection of S. enterica serotype Agona in the country.
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Affiliation(s)
- Kamela Charmaine S Ng
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Windell L Rivera
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines; Natural Sciences Research Institute, University of the Philippines, Diliman, Quezon City 1101, Philippines.
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Non-protein coding RNA genes as the novel diagnostic markers for the discrimination of Salmonella species using PCR. PLoS One 2015; 10:e0118668. [PMID: 25774907 PMCID: PMC4361174 DOI: 10.1371/journal.pone.0118668] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 01/22/2015] [Indexed: 01/03/2023] Open
Abstract
Salmonellosis, a communicable disease caused by members of the Salmonella species, transmitted to humans through contaminated food or water. It is of paramount importance, to generate accurate detection methods for discriminating the various Salmonella species that cause severe infection in humans, including S. Typhi and S. Paratyphi A. Here, we formulated a strategy of detection and differentiation of salmonellosis by a multiplex polymerase chain reaction assay using S. Typhi non-protein coding RNA (sRNA) genes. With the designed sequences that specifically detect sRNA genes from S. Typhi and S. Paratyphi A, a detection limit of up to 10 pg was achieved. Moreover, in a stool-seeding experiment with S. Typhi and S. Paratyphi A, we have attained a respective detection limit of 15 and 1.5 CFU/mL. The designed strategy using sRNA genes shown here is comparatively sensitive and specific, suitable for clinical diagnosis and disease surveillance, and sRNAs represent an excellent molecular target for infectious disease.
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Wang DN, Wu WJ, Wang T, Pan YZ, Tang KL, She XL, Ding WJ, Wang H. Salmonella L-forms: formation in human bile in vitro and isolation culture from patients' gallbladder samples by a non-high osmotic isolation technique. Clin Microbiol Infect 2015; 21:470.e9-16. [PMID: 25703211 DOI: 10.1016/j.cmi.2014.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
Abstract
Bacterial L-forms have always been considered as osmotic-pressure-sensitive cell-wall-deficient bacteria and isolation culture of L-forms must use media with high osmotic pressure. However, isolation culture of stable L-forms formed in humans and animals is very difficult because they have adapted to the physiological osmotic pressure condition of the host. We use a non-high osmotic isolation technique to isolate stable L-forms of Salmonella Typhi and Salmonella Paratyphi A from bile-inducer cultures in vitro and from patients' gallbladder specimens. Multiplex PCR assay for Salmonella-specific genes and nucleotide sequencing are used to identify the Salmonella L-forms in stable L-form isolates. Using this method, we confirmed that Salmonella Paratyphi A and Salmonella Typhi cannot be isolated from bile-inducer cultures cultured for 6 h or 48 h, but the L-forms can be isolated from 1 h to 45 days. In the 524 gallbladder samples, the positive rate for bacterial forms was 19.7% and the positive rate for Salmonella spp. was 0.6% by routine bacteriological methods. The positive rate for bacterial L-forms was 75.4% using non-high osmotic isolation culture. In the L-form isolates, the positive rate of Salmonella invA gene was 3.1%. In these invA-positive L-form isolates, four were positive for the invA and flic-d genes of Salmonella Typhi, and ten were positive for the invA and flic-a genes of Salmonella Paratyphi A.
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Affiliation(s)
- D N Wang
- Department of Medical Microbiology and Parasitology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - W J Wu
- Department of Medical Microbiology, Guiyang Medical University, Guiyang, China; Guiyang City Maternal and Child Health Care Hospital, Guiyang, China
| | - T Wang
- Department of Medical Microbiology, Guiyang Medical University, Guiyang, China.
| | - Y Z Pan
- Department of Surgery, Affiliated Hospital of Guiyang Medical University, Guiyang, China
| | - K L Tang
- Department of Surgery, Guizhou Province People's Hospital, Guiyang, China
| | - X L She
- Department of Medical Microbiology, Guiyang Medical University, Guiyang, China
| | - W J Ding
- Department of Medical Microbiology, Guiyang Medical University, Guiyang, China; Guiyang City Maternal and Child Health Care Hospital, Guiyang, China
| | - H Wang
- Department of Medical Microbiology, Guiyang Medical University, Guiyang, China.
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Mandal J, Akhter MZ, Kabir MS, Ahsan S. Development of a multiplex polymerase chain reaction protocol for the simultaneous detection of Salmonella enterica serovar Typhi and Class 1 integron. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2014. [DOI: 10.1016/s2222-1808(14)60732-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Simple and rapid detection of Salmonella by direct PCR amplification of gene fimW. Curr Microbiol 2014; 69:429-35. [PMID: 24838665 DOI: 10.1007/s00284-014-0602-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 03/15/2014] [Indexed: 10/25/2022]
Abstract
This study established a simple method of specifically detecting Salmonella species by amplifying fimW gene, which was involved in regulating Salmonella type I fimbriae expression. A pair of primers was designed to target and discriminate the 68 Salmonella strains of 23 Salmonella serovars available to us from 12 non-Salmonella strains of five different kinds of bacteria by polymerase chain reaction (PCR) amplification. Results showed that specific DNA fragment with an expected size of 477 bp was successfully amplified from all Salmonella serovars, while no target band was detected in non-Salmonella species. The sensitivity of this PCR-amplifying system reached to 1 pg DNA chromosome and 10(2) cfu of Salmonella enteritis strain CMCC(B) 50336. The above results demonstrated the method as a simple, sensitive, and specific way for Salmonella detection.
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Teh CSJ, Chua KH, Thong KL. Paratyphoid fever: splicing the global analyses. Int J Med Sci 2014; 11:732-41. [PMID: 24904229 PMCID: PMC4045793 DOI: 10.7150/ijms.7768] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 03/05/2014] [Indexed: 11/24/2022] Open
Abstract
The incidence of enteric fever caused by Salmonella enterica serovar Paratyphi A (S. Paratyphi A) is increasing in many parts of the world. Although there is no major outbreak of paratyphoid fever in recent years, S. Paratyphi A infection still remains a public health problem in many tropical countries. Therefore, surveillance studies play an important role in monitoring infections and the emergence of multidrug resistance, especially in endemic countries such as India, Nepal, Pakistan and China. In China, enteric fever was caused predominantly by S. Paratyphi A rather than by Salmonella enterica serovar Typhi (S. Typhi). Sometimes, S. Paratyphi A infection can evolve into a carrier state which increases the risk of transmission for travellers. Hence, paratyphoid fever is usually classified as a "travel-associated" disease. To date, diagnosis of paratyphoid fever based on the clinical presentation is not satisfactory as it resembles other febrile illnesses, and could not be distinguished from S. Typhi infection. With the availability of Whole Genome Sequencing technology, the genomes of S. Paratyphi A could be studied in-depth and more specific targets for detection will be revealed. Hence, detection of S. Paratyphi A with Polymerase Chain Reaction (PCR) method appears to be a more reliable approach compared to the Widal test. On the other hand, due to increasing incidence of S. Paratyphi A infections worldwide, the need to produce a paratyphoid vaccine is essential and urgent. Hence various vaccine projects that involve clinical trials have been carried out. Overall, this review provides the insights of S. Paratyphi A, including the bacteriology, epidemiology, management and antibiotic susceptibility, diagnoses and vaccine development.
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Affiliation(s)
- Cindy Shuan Ju Teh
- 1. Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur
| | - Kek Heng Chua
- 2. Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur
| | - Kwai Lin Thong
- 3. Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur
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Zhai L, Yu Q, Bie X, Lu Z, Lv F, Zhang C, Kong X, Zhao H. Development of a PCR test system for specific detection of Salmonella Paratyphi B in foods. FEMS Microbiol Lett 2014; 355:83-9. [PMID: 24725227 DOI: 10.1111/1574-6968.12443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 04/10/2014] [Accepted: 04/10/2014] [Indexed: 01/02/2023] Open
Abstract
Salmonella enterica serotype Paratyphi B is a globally distributed human-specific pathogen causing paratyphoid fever. The aim of this study was to develop a rapid and reliable polymerase chain reaction (PCR) assay for its detection in food. The SPAB_01124 gene was found to be unique to S. Paratyphi B using comparative genomics. Primers for fragments of the SPAB_01124 gene and the Salmonella-specific invA gene were used in combination to establish a multiplex PCR assay that showed 100% specificity across 45 Salmonella strains (representing 34 serotypes) and 18 non-Salmonella strains. The detection limit was 2.2 CFU mL(-1) of S. Paratyphi B after 12-h enrichment in pure culture. It was shown that co-culture with S. Typhimurium or Escherichia coli up to concentrations of 3.6 × 10(5) CFU and 3.3 × 10(4) CFU, respectively, did not interfere with PCR detection of S. Paratyphi B. In artificially contaminated milk, the assay could detect as few as 62 CFU mL(-1) after 8 h of enrichment. In conclusion, comparative genomics was found to be an efficient approach to the mining of pathogen-specific target genes, and the PCR assay that was developed from this provided a rapid, specific, and sensitive method for detection of S. Paratyphi B.
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Affiliation(s)
- Ligong Zhai
- College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, China
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Fabre L, Le Hello S, Roux C, Issenhuth-Jeanjean S, Weill FX. CRISPR is an optimal target for the design of specific PCR assays for salmonella enterica serotypes Typhi and Paratyphi A. PLoS Negl Trop Dis 2014; 8:e2671. [PMID: 24498453 PMCID: PMC3907412 DOI: 10.1371/journal.pntd.0002671] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/13/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Serotype-specific PCR assays targeting Salmonella enterica serotypes Typhi and Paratyphi A, the causal agents of typhoid and paratyphoid fevers, are required to accelerate formal diagnosis and to overcome the lack of typing sera and, in some situations, the need for culture. However, the sensitivity and specificity of such assays must be demonstrated on large collections of strains representative of the targeted serotypes and all other bacterial populations producing similar clinical symptoms. METHODOLOGY Using a new family of repeated DNA sequences, CRISPR (clustered regularly interspaced short palindromic repeats), as a serotype-specific target, we developed a conventional multiplex PCR assay for the detection and differentiation of serotypes Typhi and Paratyphi A from cultured isolates. We also developed EvaGreen-based real-time singleplex PCR assays with the same two sets of primers. PRINCIPAL FINDINGS We achieved 100% sensitivity and specificity for each protocol after validation of the assays on 188 serotype Typhi and 74 serotype Paratyphi A strains from diverse genetic groups, geographic origins and time periods and on 70 strains of bacteria frequently encountered in bloodstream infections, including 29 other Salmonella serotypes and 42 strains from 38 other bacterial species. CONCLUSIONS The performance and convenience of our serotype-specific PCR assays should facilitate the rapid and accurate identification of these two major serotypes in a large range of clinical and public health laboratories with access to PCR technology. These assays were developed for use with DNA from cultured isolates, but with modifications to the assay, the CRISPR targets could be used in the development of assays for use with clinical and other samples.
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Affiliation(s)
- Laetitia Fabre
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, WHO Collaborative Center for Reference and Research on Salmonella, Institut Pasteur, Paris, France
| | - Simon Le Hello
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, WHO Collaborative Center for Reference and Research on Salmonella, Institut Pasteur, Paris, France
| | - Chrystelle Roux
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, WHO Collaborative Center for Reference and Research on Salmonella, Institut Pasteur, Paris, France
| | - Sylvie Issenhuth-Jeanjean
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, WHO Collaborative Center for Reference and Research on Salmonella, Institut Pasteur, Paris, France
| | - François-Xavier Weill
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, WHO Collaborative Center for Reference and Research on Salmonella, Institut Pasteur, Paris, France
- * E-mail:
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Shi C, Singh P, Ranieri ML, Wiedmann M, Moreno Switt AI. Molecular methods for serovar determination of Salmonella. Crit Rev Microbiol 2013; 41:309-25. [PMID: 24228625 DOI: 10.3109/1040841x.2013.837862] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Salmonella is a diverse foodborne pathogen, which has more than 2600 recognized serovars. Classification of Salmonella isolates into serovars is essential for surveillance and epidemiological investigations; however, determination of Salmonella serovars, by traditional serotyping, has some important limitations (e.g. labor intensive, time consuming). To overcome these limitations, multiple methods have been investigated to develop molecular serotyping schemes. Currently, molecular methods to predict Salmonella serovars include (i) molecular subtyping methods (e.g. PFGE, MLST), (ii) classification using serovar-specific genomic markers and (iii) direct methods, which identify genes encoding antigens or biosynthesis of antigens used for serotyping. Here, we reviewed reported methodologies for Salmonella molecular serotyping and determined the "serovar-prediction accuracy", as the percentage of isolates for which the serovar was correctly classified by a given method. Serovar-prediction accuracy ranged from 0 to 100%, 51 to 100% and 33 to 100% for molecular subtyping, serovar-specific genomic markers and direct methods, respectively. Major limitations of available schemes are errors in predicting closely related serovars (e.g. Typhimurium and 4,5,12:i:-), and polyphyletic serovars (e.g. Newport, Saintpaul). The high diversity of Salmonella serovars represents a considerable challenge for molecular serotyping approaches. With the recent improvement in sequencing technologies, full genome sequencing could be developed into a promising molecular approach to serotype Salmonella.
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Affiliation(s)
- Chunlei Shi
- Department of Food Science, Cornell University , Ithaca, NY , USA and
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Safari Foroshani N, Karami A, Pourali F. Simultaneous and Rapid Detection of Salmonella typhi, Bacillus anthracis, and Yersinia pestis by Using Multiplex Polymerase Chain Reaction (PCR). IRANIAN RED CRESCENT MEDICAL JOURNAL 2013; 15:e9208. [PMID: 24719692 PMCID: PMC3971784 DOI: 10.5812/ircmj.9208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 06/02/2013] [Accepted: 07/14/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND Salmonella typhi, Bacillus anthracis, and Yersinia pestis are some serious human pathogens, which their early diagnosis is of great importance. Salmonella typhi, Bacillus anthracis, and Yersinia pestis cause typhoid fever, anthrax, and plague respectively. These bacteria can be used to make biologic weapons. OBJECTIVES In this study, we designed a new and rapid diagnostic method based on Uniplex and Multiplex PCR method. MATERIALS AND METHODS Uniplex and multiplex Polymerase Chain Reaction (PCR) were conducted on virulent genes of hp and invA of Salmonella typhimurium, Pa and chr of Bacillus anthracis, and pla of Yersinia pestis. A genome from other bacteria was used to study the specificity of the primer and the PCR test. RESULTS Standard strains used in this study showed that primers were specific. As for sensitivity, it was shown that this method can diagnose 1-10 copies of the genome, or 1-10 Colony Forming Units (CFU) for each of the bacteria. All pieces except anthrax were sequenced in PCR to validate the product. DNA fragment resulted from Bacillus anthracis was confirmed by restriction enzyme digestions. CONCLUSION The designed methods are accurate, rapid, and inexpensive to find and differentiate these bacteria from similar bacteria. They can be applied for rapid diagnosis of these agents in different specimens, and bioterrorism cases.
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Affiliation(s)
| | - Ali Karami
- Research Center of Molecular Biology, Baqiyatallah University of Medical Sciences, Tehran, IR Iran
- Corresponding Author: Ali Karami, Ali Karami, Research Center of Molecular Biology, Baqiyatallah University of Medical Sciences, P.O. Box: 19945-581, Tehran, IR Iran. Tel: +98-2188039883, Fax: +98-2188057023., E-mail:
| | - Fatemeh Pourali
- Research Center of Molecular Biology, Baqiyatallah University of Medical Sciences, Tehran, IR Iran
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Walawalkar YD, Gaind R, Nayak V. Study on Salmonella Typhi occurrence in gallbladder of patients suffering from chronic cholelithiasis-a predisposing factor for carcinoma of gallbladder. Diagn Microbiol Infect Dis 2013; 77:69-73. [PMID: 23790418 DOI: 10.1016/j.diagmicrobio.2013.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 05/12/2013] [Accepted: 05/15/2013] [Indexed: 01/11/2023]
Abstract
Cholelithiasis is frequently associated with carcinoma of gallbladder, and the presence of Salmonella Typhi in gallbladder of patients suffering from cholelithiasis is implicated as a predisposing factor for carcinogenesis. This study was conducted on patients suffering from chronic cholelithiasis from a region in North India-endemic area for enteric fever with high incidence of gallstones and gallbladder cancer. Since culture studies rarely reveal the chronic Salmonella Typhi persistence, we use PCR assay to specifically amplify the H1-d flagellin gene sequence homologous with Salmonella Typhi. Seven cases (17.5%), none of which were positive for culture, showed positive PCR results for Salmonella Typhi, 4 (10%) of which were tissue, 2 bile (5%), and 1 gallstone (2.5%). The chronic existence of Salmonella Typhi in gallbladder disease was confirmed. Thus, the study would indicate the importance of vaccination so as to prevent chronic infection and need for early diagnostic tools to prevent any further complications.
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Affiliation(s)
- Yogesh D Walawalkar
- Department of Biological Sciences, Birla Institute of Technology & Science, Goa, India
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Ravan H, Yazdanparast R. Development and evaluation of a loop-mediated isothermal amplification method in conjunction with an enzyme-linked immunosorbent assay for specific detection of Salmonella serogroup D. Anal Chim Acta 2012; 733:64-70. [DOI: 10.1016/j.aca.2012.04.034] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 04/24/2012] [Accepted: 04/26/2012] [Indexed: 11/25/2022]
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Ravan H, Yazdanparast R. Development of a new loop-mediated isothermal amplification assay for prt (rfbS) gene to improve the identification of Salmonella serogroup D. World J Microbiol Biotechnol 2012; 28:2101-6. [PMID: 22806032 DOI: 10.1007/s11274-012-1014-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 01/30/2012] [Indexed: 12/14/2022]
Abstract
Loop-mediated isothermal amplification (LAMP) is a promising nucleic acid assay for rapid and cost-effective detection of pathogen-specific sequences within a sample. Development of an appropriate taxonomic group-specific LAMP assay highly relies on the design of proper primers to cover all major members of the taxon. Regarding this fact, we designed and evaluated a new LAMP primer set specific to prt (rfbS) gene for rapid identification of Salmonella serogroup D serotypes. Unlike the previously reported LAMP assay for serogroup D which detects solely the non-typhoidal serotypes; the new LAMP primers set detects both typhoidal and non-typhoidal serotypes of this serogroup with a detection limit of 10 CFU/rection. Furthermore, the technique was successfully applied to artificially contaminated meat samples with an inoculation level of 1-5 CFU/250 ml of Salmonella Enteritidis, following a 5-h pre-enrichment step in tryptic soy broth. Overall, the new LAMP assay and its optimized setup would be useful for fast diagnosis of food poisoning incidents caused by these bacteria.
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Affiliation(s)
- Hadi Ravan
- Institute of Biochemistry and Biophysics, University of Tehran, P. O. Box 13145-1384, Tehran, Iran
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Marathe SA, Chowdhury R, Bhattacharya R, Nagarajan AG, Chakravortty D. Direct detection of Salmonella without pre-enrichment in milk, ice-cream and fruit juice by PCR against hilA gene. Food Control 2012. [DOI: 10.1016/j.foodcont.2011.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Liu B, Zhang L, Zhu X, Shi C, Chen J, Liu W, He X, Shi X. PCR identification of Salmonella serogroups based on specific targets obtained by comparative genomics. Int J Food Microbiol 2011; 144:511-8. [DOI: 10.1016/j.ijfoodmicro.2010.11.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 11/01/2010] [Accepted: 11/07/2010] [Indexed: 11/28/2022]
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Nandagopal B, Sankar S, Lingesan K, Appu KC, Padmini B, Sridharan G, Gopinath AK. Prevalence of Salmonella typhi among patients with febrile illness in rural and peri-urban populations of Vellore district, as determined by nested PCR targeting the flagellin gene. Mol Diagn Ther 2010; 14:107-12. [PMID: 20359254 DOI: 10.1007/bf03256360] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND AND OBJECTIVE Fever is one of the most common illnesses in all age groups in India. Typhoid fever is a continuing problem in developing countries such as India, which has poor sanitation facilities. The diagnosis of typhoid fever is still made by conventional culture-based isolation and identification. Serologic diagnostic tests, though widely used, have many deficiencies. Our objective was to investigate a molecular nested polymerase chain reaction (nPCR) technique to detect Salmonella typhi among patients with febrile illness in rural and peri-urban communities in Vellore district (Tamil Nadu, India). METHODS nPCR targeting the flagellin gene (fliC) was carried out using HotStar Taq DNA polymerase on DNA extracted from the buffy coat fraction of blood samples. Blood culture was done in a completely automated blood culture system, BacT/Alert(R), on prospectively collected blood samples. Relevant clinicopathologic data were obtained. RESULTS nPCR was found to have a lower limit of detection of 0.01 colony-forming units per milliliter. The prevalence of typhoid fever as estimated by nPCR was 4.7% in pyrexia of unknown origin (PUO) in the rural/peri-urban communities of Vellore district. The prevalence of S. typhi as estimated by blood culture was 2.0%, which was lower than the nPCR estimation. nPCR had sensitivity and specificity of 100% and 97.3%, respectively. The observed agreement between blood culture and nPCR was 0.973 and the Kappa coefficient was 0.59 (p < 0.0001). The frequency of typhoid fever as detected by nPCR was 4.35% among rural patients and 5.32% among peri-urban individuals. CONCLUSION nPCR on DNA extracts of buffy-coat samples using HotStar Taq was found to be a valuable and specific technique for diagnosis of typhoid fever.
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Affiliation(s)
- Balaji Nandagopal
- Sri Narayani Hospital & Research Centre, Vellore, Tamil Nadu, India.
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Development of a novel multiplex PCR for the detection and differentiation of Salmonella enterica serovars Typhi and Paratyphi A. Res Microbiol 2010; 161:243-8. [DOI: 10.1016/j.resmic.2010.03.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 03/03/2010] [Accepted: 03/11/2010] [Indexed: 11/24/2022]
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Identification by PCR of non-typhoidal Salmonella enterica serovars associated with invasive infections among febrile patients in Mali. PLoS Negl Trop Dis 2010; 4:e621. [PMID: 20231882 PMCID: PMC2834738 DOI: 10.1371/journal.pntd.0000621] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 01/20/2010] [Indexed: 11/29/2022] Open
Abstract
Background In sub-Saharan Africa, non-typhoidal Salmonella (NTS) are emerging as a prominent cause of invasive disease (bacteremia and focal infections such as meningitis) in infants and young children. Importantly, including data from Mali, three serovars, Salmonella enterica serovar Typhimurium, Salmonella Enteritidis and Salmonella Dublin, account for the majority of non-typhoidal Salmonella isolated from these patients. Methods We have extended a previously developed series of polymerase chain reactions (PCRs) based on O serogrouping and H typing to identify Salmonella Typhimurium and variants (mostly I 4,[5],12:i:-), Salmonella Enteritidis and Salmonella Dublin. We also designed primers to detect Salmonella Stanleyville, a serovar found in West Africa. Another PCR was used to differentiate diphasic Salmonella Typhimurium and monophasic Salmonella Typhimurium from other O serogroup B, H:i serovars. We used these PCRs to blind-test 327 Salmonella serogroup B and D isolates that were obtained from the blood cultures of febrile patients in Bamako, Mali. Principal Findings We have shown that when used in conjunction with our previously described O-serogrouping PCR, our PCRs are 100% sensitive and specific in identifying Salmonella Typhimurium and variants, Salmonella Enteritidis, Salmonella Dublin and Salmonella Stanleyville. When we attempted to differentiate 171 Salmonella Typhimurium (I 4,[ 5],12:i:1,2) strains from 52 monophasic Salmonella Typhimurium (I 4,[5],12:i:-) strains, we were able to correctly identify 170 of the Salmonella Typhimurium and 51 of the Salmonella I 4,[5],12:i:- strains. Conclusion We have described a simple yet effective PCR method to support surveillance of the incidence of invasive disease caused by NTS in developing countries. The genus Salmonella has more than 2500 serological variants (serovars), such as Salmonella enterica serovar Typhi and Salmonella Paratyphi A and B, that cause, respectively, typhoid and paratyphoid fevers (enteric fevers), and a large number of non-typhoidal Salmonella (NTS) serovars that cause gastroenteritis in healthy hosts. In young infants, the elderly and immunocompromised hosts, NTS can cause severe, fatal invasive disease. Multiple studies of pediatric patients in sub-Saharan Africa have documented the important role of NTS, in particular Salmonella Typhimurium and Salmonella Enteritidis (and to a lesser degree Salmonella Dublin), as invasive bacterial pathogens. Salmonella spp. are isolated from blood and identified by standard microbiological techniques and the serovar is ascertained by agglutination with commercial antisera. PCR-based typing techniques are becoming increasingly popular in developing countries, in part because high quality typing sera are difficult to obtain and expensive and H serotyping is technically difficult. We have developed a series of polymerase chain reactions (PCRs) to identify Salmonella Typhimurium and variants, Salmonella Enteritidis and Salmonella Dublin. We successfully identified 327 Salmonella isolates using our multiplex PCR. We also designed primers to detect Salmonella Stanleyville, a serovar found in West Africa. Another PCR generally differentiated diphasic Salmonella Typhimurium and monophasic Salmonella Typhimurium variant strains from other closely related strains. The PCRs described here will enable more laboratories in developing countries to serotype NTS that have been isolated from blood.
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Gallstones play a significant role in Salmonella spp. gallbladder colonization and carriage. Proc Natl Acad Sci U S A 2010; 107:4353-8. [PMID: 20176950 DOI: 10.1073/pnas.1000862107] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Salmonella enterica serovar Typhi can colonize the gallbladder and persist in an asymptomatic carrier state that is frequently associated with the presence of gallstones. We have shown that salmonellae form bile-mediated biofilms on human gallstones and cholesterol-coated surfaces in vitro. Here, we test the hypothesis that biofilms on cholesterol gallbladder stones facilitate typhoid carriage in mice and men. Naturally resistant (Nramp1(+/+)) mice fed a lithogenic diet developed cholesterol gallstones that supported biofilm formation during persistent serovar Typhimurium infection and, as a result, demonstrated enhanced fecal shedding and enhanced colonization of gallbladder tissue and bile. In typhoid endemic Mexico City, 5% of enrolled cholelithiasis patients carried serovar Typhi, and bacterial biofilms could be visualized on gallstones from these carriers whereas significant biofilms were not detected on gallstones from Escherichia coli infected gallbladders. These findings offer direct evidence that gallstone biofilms occur in humans and mice, which facilitate gallbladder colonization and shedding.
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Kumar A, Balachandran Y, Gupta S, Khare S, Suman. Quick PCR based diagnosis of typhoid using specific genetic markers. Biotechnol Lett 2010; 32:707-12. [PMID: 20140635 DOI: 10.1007/s10529-010-0211-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 01/14/2010] [Accepted: 01/14/2010] [Indexed: 10/19/2022]
Abstract
A quick multiplex PCR based detection method was developed for early diagnosis of typhoid using specific genetic markers of S. typhi. Primers of tyv gene, flag gene, viaB gene and ratA gene confirmed the specificity and sensitivity of the PCR. The serum samples of the suspected typhoid patients were taken directly for PCR without culturing and isolating genomic DNA. Overall diagnosis required 2 h which is the least time ever reported for a PCR based methods. The sensitivity of the method is up to 5 fg genomic DNA. The genetic markers are specific and the four pairs of primers give selective amplification and differentiate S. typhi from closely related S. typhimurium.
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Affiliation(s)
- Ashok Kumar
- Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India.
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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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Park SH, Kim HJ, Cho WH, Kim JH, Oh MH, Kim SH, Lee BK, Ricke SC, Kim HY. Identification of Salmonella enterica subspecies I, Salmonella enterica serovars Typhimurium, Enteritidis and Typhi using multiplex PCR. FEMS Microbiol Lett 2009; 301:137-46. [PMID: 19843307 DOI: 10.1111/j.1574-6968.2009.01809.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
This study was designed to develop a multiplex PCR method with five specific primer pairs for the detection of Salmonella spp., Salmonella subspecies I, Salmonella enterica serovars Typhimurium, Typhi and Enteritidis. A multiplex PCR was constructed with five primer pairs for the detection of Salmonella and pathogenic Salmonella serovars, including a specific primer pair for Salmonella Typhi, based on the sequence comparison between genomic DNA sequences of 12 Salmonella strains. Each primer pair was specifically targeted to Salmonella spp., Salmonella subspecies I, Salmonella Typhimurium, Typhi and Enteritidis. This multiplex PCR was evaluated with various DNAs of Salmonella serovars that yielded high specificity for amplifying the expected PCR products of Salmonella serovars. Using this primer pair, a set of multiplex PCR was performed for the rapid identification of salmonellae and major pathogenic Salmonella serovars. Although this multiplex PCR method will need to be evaluated for a wide range of Salmonella serovars among multilaboratories, it should be useful for identifying clinically significant strains of Salmonella serovars rapidly and accurately without the need for serological testing.
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Affiliation(s)
- Si Hong Park
- Institute of Life Sciences and Resources, Graduate School of Biotechnology, Kyung Hee University, Yongin, Korea
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Polymerase Chain Reaction for the Rapid Detection and Serovar Identification of Salmonella in Food and Feeding Stuff. FOOD ANAL METHOD 2008. [DOI: 10.1007/s12161-008-9057-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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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Saroj SD, Shashidhar R, Karani M, Bandekar JR. Distribution of Salmonella pathogenicity island (SPI)-8 and SPI-10 among different serotypes of Salmonella. J Med Microbiol 2008; 57:424-427. [DOI: 10.1099/jmm.0.47630-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Many virulence phenotypes of Salmonella enterica are encoded by genes located on pathogenicity islands. Based on genome analysis, it is predicted that Salmonella pathogenicity island (SPI)-8 is restricted to Salmonella serovars Typhi and Paratyphi A, and SPI-10 to Salmonella serovars Typhi, Paratyphi, Enteritidis, Dublin and Gallinarum. This study was conducted to investigate the distribution of SPI-8 and SPI-10 among Salmonella isolates from sprouts, fish, water and blood. A total of 110 Salmonella isolates and 6 Salmonella serovars from the Microbial Type Culture Collection, Chandigarh, India, were screened. All isolates belonging to Salmonella serovars Washington, Enteritidis and Paratyphi A had both SPI-8 and SPI-10. All Salmonella serovar Typhi isolates from water and blood had both SPI-8 and SPI-10, whereas isolates from fish contained only SPI-8. SPI-8 and SPI-10 were also detected in only 3 out of 42 isolates belonging to Salmonella serovar Typhimurium. Both SPI-8 and SPI-10 were absent in Salmonella serovars Worthington, Dublin, Paratyphi B and Paratyphi C. These results contradict the predictions from Salmonella genome sequences available in GenBank and indicate that SPI-8 and SPI-10 are widely distributed among Salmonella serovars and that virulence factors other than those on SPI-8 and SPI-10 may be responsible for host specificity. This is the first report on the distribution of SPIs in Salmonella isolates from India.
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Affiliation(s)
- Sunil D. Saroj
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - R. Shashidhar
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Manisha Karani
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Jayant R. Bandekar
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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Calvó L, Martínez-Planells A, Pardos-Bosch J, Garcia-Gil LJ. A New Real-Time PCR Assay for the Specific Detection of Salmonella spp. Targeting the bipA Gene. FOOD ANAL METHOD 2008. [DOI: 10.1007/s12161-007-9008-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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