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Nadiya S, Kolla HB, Reddy PN. Optimization and evaluation of a multiplex PCR assay for detection of Staphylococcus aureus and its major virulence genes for assessing food safety. Braz J Microbiol 2023; 54:311-321. [PMID: 36690906 PMCID: PMC9944222 DOI: 10.1007/s42770-023-00906-6] [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: 09/17/2022] [Accepted: 01/15/2023] [Indexed: 01/25/2023] Open
Abstract
Staphylococcus aureus is a natural commensal microflora of humans which causes opportunistic infections due to its large arsenal of exotoxins, invasion, immune evasion, and antibiotic resistance mechanisms. The primary goal of this study is to develop a multiplex PCR (mPCR) assay for simultaneous detection of Staphylococcus aureus (nuc) and its virulence genes coding for prominent exotoxins namely alpha hemolysin (hla), enterotoxins A (sea), enterotoxin B (seb), toxic shock syndrome toxin (tsst-1), and the gene coding for methicillin resistance (mecA). A competitive internal amplification control (IAC) was included in the assay to exclude the false negative outcomes. Highly specific primer pairs were designed for the target genes using in silico resources. At the outset, monoplex PCRs were standardized using reference S. aureus strains. Primer specificity to the target genes was authenticated through restriction digestion analysis of amplified PCR products. Multiplex PCR was optimized in increments of one gene starting with nuc and IAC amplified simultaneously using one pair of primers (nuc) in a competitive manner. The mPCR assay was found to be highly sensitive with a detection limit of ~10 CFUs per reaction for pure cultures. Multiplex PCR assay was further evaluated on the retail and processed food samples to test the prevalence of S. aureus and study their exotoxin profiles. Of the 57 samples examined, 13 samples (22.80%) were found to be contaminated with S. aureus whose DNA was extracted after a 6-h enrichment period. Among these, a high percentage of hemolytic and enterotoxin A positive strains were encountered. The mPCR assay developed in this study would be a useful tool for rapid and reliable monitoring of S. aureus for food quality testing and from clinical infections.
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Affiliation(s)
- Shaik Nadiya
- Department of Biotechnology, Vignan's Foundation for Science, Technology and Research (Deemed to be University), Vadlamudi, Andhra Pradesh, Guntur district, 522 213, India
| | - Harish Babu Kolla
- Department of Biotechnology, Vignan's Foundation for Science, Technology and Research (Deemed to be University), Vadlamudi, Andhra Pradesh, Guntur district, 522 213, India
| | - Prakash Narayana Reddy
- Department of Microbiology, Dr. V.S. Krishna Government Degree College (Autonomous), Maddilapalem, Visakhapatnam, Andhra Pradesh, 530 013, India.
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Onohuean H, Okoh AI, Nwodo UU. Epidemiologic potentials and correlational analysis of Vibrio species and virulence toxins from water sources in greater Bushenyi districts, Uganda. Sci Rep 2021; 11:22429. [PMID: 34789791 PMCID: PMC8599681 DOI: 10.1038/s41598-021-01375-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 10/20/2021] [Indexed: 12/29/2022] Open
Abstract
Adequate water supply is one of the public health issues among the population living in low-income settings. Vibriosis remain a significant health challenge drawing the attention of both healthcare planners and researchers in South West districts of Uganda. Intending to clamp down the disease cases in the safest water deprive locality, we investigated the virulent toxins as contaminants and epidemiologic potentials of Vibrio species recovered from surface waters in greater Bushenyi districts, Uganda. Surface water sources within 46 villages located in the study districts were obtained between June and October 2018. Standard microbiological and molecular methods were used to analyse samples. Our results showed that 981 presumptive isolates retrieved cell counts of 10-100 CFU/g, with, with (640) 65% confirmed as Vibrio genus using polymerase chain reaction, which is distributed as follows; V. vulnificus 46/640 (7.2%), V. fluvialis 30/594 (5.1), V. parahaemolyticus 21/564 (3.7), V. cholera 5/543 (0.9), V. alginolyticus 62/538 (11.5) and V. mimicus 20/476 (4.2). The virulence toxins observed were heat-stable enterotoxin (stn) 46 (82.10%), V. vulnificus virulence gene (vcgCPI) 40 (87.00%), extracellular haemolysin gene {vfh 21 (70.00)} and Heme utilization protein gene {hupO 5 (16.70)}. The cluster analysis depicts hupO (4.46% n = 112); vfh (18.75%, n = 112); vcgCPI and stn (35.71%, & 41.07%, n = 112). The principal component analysis revealed the toxins (hupO, vfh) were correlated with the isolate recovered from Bohole water (BW) source, while (vcgCPI, stn) toxins are correlated with natural raw water (NRW) and open springs (OS) water sources isolates. Such observation indicates that surface waters sources are highly contaminated with an odds ratio of 1.00, 95% CI (70.48-90.5), attributed risk of (aR = 64.29) and relative risk of (RR = 73.91). In addition, it also implies that the surface waters sources have > 1 risk of contamination with vfh and > six times of contamination with hupO (aR = 40, - 66). This is a call of utmost importance to the population, which depends on these water sources to undertake appropriate sanitation, personal hygienic practices and potential measures that ensure water quality.
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Affiliation(s)
- Hope Onohuean
- SA-MRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, 5700, South Africa.
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag 1314, Alice, 5700, Eastern Cape, South Africa.
- Biopharmaceutics Unit, Department of Pharmacology and Toxicology, School of Pharmacy, Kampala International University, Western-Campus, Ishaka-Bushenyi, Uganda.
| | - Anthony I Okoh
- SA-MRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, 5700, South Africa
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag 1314, Alice, 5700, Eastern Cape, South Africa
| | - Uchechukwu U Nwodo
- SA-MRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, 5700, South Africa
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag 1314, Alice, 5700, Eastern Cape, South Africa
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Yilmaz T, Goluch ED. A comprehensive review of conventional techniques and biosensor systems developed for in situ detection of vibrio cholerae. Trends Analyt Chem 2021. [DOI: 10.1016/j.trac.2021.116416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nasreen T, Hussain NAS, Islam MT, Orata FD, Kirchberger PC, Case RJ, Alam M, Yanow SK, Boucher YF. Simultaneous Quantification of Vibrio metoecus and Vibrio cholerae with Its O1 Serogroup and Toxigenic Subpopulations in Environmental Reservoirs. Pathogens 2020; 9:pathogens9121053. [PMID: 33339261 PMCID: PMC7766680 DOI: 10.3390/pathogens9121053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/11/2020] [Accepted: 12/12/2020] [Indexed: 12/14/2022] Open
Abstract
Vibrio metoecus is a recently described aquatic bacterium and opportunistic pathogen, closely related to and often coexisting with Vibrio cholerae. To study the relative abundance and population dynamics of both species in aquatic environments of cholera-endemic and cholera-free regions, we developed a multiplex qPCR assay allowing simultaneous quantification of total V. metoecus and V. cholerae (including toxigenic and O1 serogroup) cells. The presence of V. metoecus was restricted to samples from regions that are not endemic for cholera, where it was found at 20% of the abundance of V. cholerae. In this environment, non-toxigenic O1 serogroup V. cholerae represents almost one-fifth of the total V. cholerae population. In contrast, toxigenic O1 serogroup V. cholerae was also present in low abundance on the coast of cholera-endemic regions, but sustained in relatively high proportions throughout the year in inland waters. The majority of cells from both Vibrio species were recovered from particles rather than free-living, indicating a potential preference for attached versus planktonic lifestyles. This research further elucidates the population dynamics underpinning V. cholerae and its closest relative in cholera-endemic and non-endemic regions through culture-independent quantification from environmental samples.
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Affiliation(s)
- Tania Nasreen
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; (T.N.); (N.A.S.H.); (M.T.I.); (F.D.O.); (R.J.C.)
| | - Nora A. S. Hussain
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; (T.N.); (N.A.S.H.); (M.T.I.); (F.D.O.); (R.J.C.)
| | - Mohammad Tarequl Islam
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; (T.N.); (N.A.S.H.); (M.T.I.); (F.D.O.); (R.J.C.)
| | - Fabini D. Orata
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; (T.N.); (N.A.S.H.); (M.T.I.); (F.D.O.); (R.J.C.)
| | - Paul C. Kirchberger
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA;
| | - Rebecca J. Case
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; (T.N.); (N.A.S.H.); (M.T.I.); (F.D.O.); (R.J.C.)
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Munirul Alam
- Centre for Communicable Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B), Dhaka 1000, Bangladesh;
| | - Stephanie K. Yanow
- School of Public Health, University of Alberta, Edmonton, AB T6G 1C9, Canada;
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Yann F. Boucher
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; (T.N.); (N.A.S.H.); (M.T.I.); (F.D.O.); (R.J.C.)
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), National University of Singapore, Singapore 637551, Singapore
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore 117549, Singapore
- Correspondence:
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Kongrueng J, Srinitiwarawong K, Nishibuchi M, Mittraparp-Arthorn P, Vuddhakul V. Characterization and CRISPR-based genotyping of clinical trh-positive Vibrio parahaemolyticus. Gut Pathog 2018; 10:48. [PMID: 30459849 PMCID: PMC6233571 DOI: 10.1186/s13099-018-0275-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/08/2018] [Indexed: 01/15/2023] Open
Abstract
Background Vibrio parahaemolyticus is a causative agent of gastroenteritis. Most of the clinical isolates carry either tdh and/or trh genes which are considered as the major virulence genes of this pathogen. In this study, the clinical isolates of V. parahaemolyticus carrying trh gene (n = 73) obtained from 1886 to 2012 from various countries were investigated for the urease production, haemolytic activity, and biofilm formation. In addition, the potential of clustered regularly interspaced short palindromic repeats (CRISPR)-based genotyping among these isolates was investigated. Results In this study, no significant differences were observed in the urease production between tdh + trh1+ and tdh + trh2+ isolates (p = 0.063) and between the tdh - trh1+ and tdh - trh2+ isolates (p = 0.788). The isolates carrying only the trh gene showed variation in their haemolytic activity. The ratio of urease production and haemolytic activity between the trh1+ and trh2+ isolates and biofilm formation of trh + V. parahaemolyticus isolates were not significantly different. Sixteen of thirty-four tested isolates (47.0%) of trh + V. parahaemolyticus were positive for CRISPR detection. The discriminatory power index (DI) of CRISPR-virulence typing was higher than the DI obtained by CRISPR typing alone. Conclusion The tdh and trh genes were not involved in urease production in the trh + V. parahaemolyticus, and variation of haemolytic activity detected in V. parahaemolyticus carrying only the trh gene might be correlated to the sequence variation within trh1 and trh2 genes. Additionally, biofilm production of V. parahaemolyticus was not associated with harboring of virulence genes. For genotyping, CRISPR sequences combined with virulence genes can be used as genetic markers to differentiate trh + V. parahaemolyticus strains.
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Affiliation(s)
- Jetnapang Kongrueng
- 1Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Thailand
| | - Kanchana Srinitiwarawong
- 1Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Thailand
| | | | | | - Varaporn Vuddhakul
- 1Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Thailand
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Hao M, Zhang P, Li B, Liu X, Zhao Y, Tan H, Sun C, Wang X, Wang X, Qiu H, Wang D, Diao B, Jing H, Yang R, Kan B, Zhou L. Development and evaluation of an up-converting phosphor technology-based lateral flow assay for the rapid, simultaneous detection of Vibrio cholerae serogroups O1 and O139. PLoS One 2017; 12:e0179937. [PMID: 28662147 PMCID: PMC5491072 DOI: 10.1371/journal.pone.0179937] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 06/06/2017] [Indexed: 01/08/2023] Open
Abstract
Vibrio cholerae serogroups O1 and O139 are etiological agents of cholera, a serious and acute diarrheal disease, and rapid detection of V. cholerae is a key method for preventing and controlling cholera epidemics. Here, a point of care testing (POCT) method called Vch-UPT-LF, which is an up-converting phosphor technology-based lateral flow (UPT-LF) assay with a dual-target detection mode, was developed to detect V. cholerae O1 and O139 simultaneously from one sample loading. Although applying an independent reaction pair made both detection results for the two Vch-UPT-LF detection channels more stable, the sensitivity slightly declined from 104 to 105 colony-forming units (CFU) mL-1 compared with that of the single-target assay, while the quantification ranges covering four orders of magnitude were maintained. The strip showed excellent specificity for seven Vibrio species that are highly related genetically, and nine food-borne species whose transmission routes are similar to those of V. cholerae. The legitimate arrangement of the two adjacent test lines lessened the mutual impact of the quantitation results between the two targets, and the quantification values did not differ by more than one order of magnitude when the samples contained high concentrations of both V. cholerae O1 and O139. Under pre-incubation conditions, 1×101 CFU mL-1 of V. cholerae O1 or O139 could be detected in fewer than 7 h, while the Vch-UPT-LF assay exhibited sensitivity as high as a real-time fluorescent polymerase chain reaction with fewer false-positive results. Therefore, successful development of Vch-UPT-LF as a dual-target assay for quantitative detection makes this assay a good candidate POCT method for the detection and surveillance of epidemic cholera.
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Affiliation(s)
- Min Hao
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
- Beijing Chaoyang District Center for Disease Control and Prevention, Beijing, P. R. China
| | - Pingping Zhang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, P. R. China
- Beijing Key Laboratory of POCT for Bioemergency and Clinic (No. BZ0329), Beijing, P. R. China
| | - Baisheng Li
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, Guangdong, P. R. China
| | - Xiao Liu
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, P. R. China
- Beijing Key Laboratory of POCT for Bioemergency and Clinic (No. BZ0329), Beijing, P. R. China
- Chongqing Entry Exit Inspection and Quarantine Bureau, Chongqing, P. R. China
| | - Yong Zhao
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, P. R. China
- Beijing Key Laboratory of POCT for Bioemergency and Clinic (No. BZ0329), Beijing, P. R. China
| | - Hailing Tan
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, Guangdong, P. R. China
| | - Chongyun Sun
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, P. R. China
- Beijing Key Laboratory of POCT for Bioemergency and Clinic (No. BZ0329), Beijing, P. R. China
- Department of Clinical Laboratory, Chinese People’s Liberation Army General Hospital, Beijing, P. R. China
| | - Xiaochen Wang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, P. R. China
- Beijing Key Laboratory of POCT for Bioemergency and Clinic (No. BZ0329), Beijing, P. R. China
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, Jilin, P. R. China
| | - Xinrui Wang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, P. R. China
- Beijing Key Laboratory of POCT for Bioemergency and Clinic (No. BZ0329), Beijing, P. R. China
- Institute for Plague Prevention and Control of Hebei Province, Zhangjiakou, Hebei, P. R. China
| | - Haiyan Qiu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Duochun Wang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Baowei Diao
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Huaiqi Jing
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Ruifu Yang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, P. R. China
- Beijing Key Laboratory of POCT for Bioemergency and Clinic (No. BZ0329), Beijing, P. R. China
| | - Biao Kan
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang, P. R. China
| | - Lei Zhou
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, P. R. China
- Beijing Key Laboratory of POCT for Bioemergency and Clinic (No. BZ0329), Beijing, P. R. China
- College of Life Sciences, Northwest University, Xi’an, Shanxi, P. R. China
- National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi’an, Shanxi, P. R. China
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Ramachandran N, Ramlal S, Batra HV. Confirmed identification and toxin profiling of Campylobacter jejuni using a thermostabilized multiplex PCR formulation. APMIS 2017; 125:641-649. [PMID: 28574617 DOI: 10.1111/apm.12700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 02/27/2017] [Indexed: 11/28/2022]
Abstract
Cytolethal distending toxin (CDT) producing Campylobacter jejuni species are one of the leading causes of human gastroenteritis worldwide. The main intent of the study was to develop a multiplex PCR assay for the confirmed identification and toxin profiling of C. jejuni. The genes targeted were rpo B as genus specific, hip O for species; cdt A, cdt B, cdt C encoding respective subunit proteins of CDT with Internal Amplification Control (IAC). To enhance its application as a pre-mixed ready-to-use format, the master mix of developed mPCR was dried by lyophilization and stability was assessed. Thermostabilized reagents showed stability of 1.5 months at room-temperature and upto six months at 4 °C without any loss of functionality. The assay was evaluated on a number of presumptive Campylobacter isolates along with biochemical tests. Results obtained indicated the accurate identification of C. jejuni by developed mPCR format in contrast to misconception associated with biochemical assays. The assay was also tested on spiked samples for its real-time utility. Altogether, the room-temperature storable and ready-to- use mPCR format developed in this study could be preferred for rapid detection and confirmed identification of toxigenic strains of C. jejuni in place of conventional biochemical assays.
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Affiliation(s)
- Nitya Ramachandran
- Microbiology Division, Defence Food Research Laboratory, Mysore, Karnataka, India
| | - Shylaja Ramlal
- Microbiology Division, Defence Food Research Laboratory, Mysore, Karnataka, India
| | - Harsh Vardhan Batra
- Microbiology Division, Defence Food Research Laboratory, Mysore, Karnataka, India
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Teng J, Yuan F, Ye Y, Zheng L, Yao L, Xue F, Chen W, Li B. Aptamer-Based Technologies in Foodborne Pathogen Detection. Front Microbiol 2016; 7:1426. [PMID: 27672383 PMCID: PMC5018482 DOI: 10.3389/fmicb.2016.01426] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 08/29/2016] [Indexed: 11/13/2022] Open
Abstract
Aptamers are single stranded DNA or RNA ligands, which can be selected by a method called systematic evolution of ligands by exponential enrichment (SELEX); and they can specifically recognize and bind to their targets. These unique characteristics of aptamers offer great potentials in applications such as pathogen detection and biomolecular screening. Pathogen detection is the critical means in detecting and identifying the problems related to public health and food safety; and only the rapid, sensitive and efficient detection technologies can enable the users to make the accurate assessments on the risks of infections (humans and animals) or contaminations (foods and other commodities) caused by various pathogens. This article reviews the development in the field of the aptamer-based approaches for pathogen detection, including whole-cell SELEX and Genomic SELEX. Nowadays, a variety of aptamer-based biosensors have been developed for pathogen detection. Thus, in this review, we also cover the development in aptamer-based biosensors including optical biosensors for multiple pathogen detection by multiple-labeling or label-free models such as fluorescence detection and surface plasmon resonance, electrochemical biosensors and lateral chromatography test strips, and their applications in pathogen detection and biomolecular screening. While notable progress has been made in the field in the last decade, challenges or drawbacks in their applications such as pathogen detection and biomolecular screening remain to be overcome.
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Affiliation(s)
- Jun Teng
- College of Food Science and Engineering, Hefei University of Technology, HefeiChina
| | - Fang Yuan
- Animal Quarantine Laboratory, Jiangsu Entry-Exit Inspection and Quarantine Bureau, NanjingChina
| | - Yingwang Ye
- College of Food Science and Engineering, Hefei University of Technology, HefeiChina
| | - Lei Zheng
- College of Food Science and Engineering, Hefei University of Technology, HefeiChina
| | - Li Yao
- College of Food Science and Engineering, Hefei University of Technology, HefeiChina
| | - Feng Xue
- Animal Quarantine Laboratory, Jiangsu Entry-Exit Inspection and Quarantine Bureau, NanjingChina
| | - Wei Chen
- College of Food Science and Engineering, Hefei University of Technology, HefeiChina
| | - Baoguang Li
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MDUSA
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Nagaraj S, Ramlal S, Venkataswamachari BP, Paul S, Kingston J, Batra HV. Differentiation of entC1 from entC2/entC3 with a single primer pair using simple and rapid SYBR Green-based RT-PCR melt curve analysis. Appl Microbiol Biotechnol 2016; 100:8495-506. [PMID: 27245675 DOI: 10.1007/s00253-016-7637-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/09/2016] [Accepted: 05/15/2016] [Indexed: 12/11/2022]
Abstract
In spite of their involvement in foodborne illness, the epidemiological relevance of staphylococcal enterotoxin C (SEC) subtypes is poorly documented may be due to high sequence similarity. Among subtypes, SEC1, SEC2, and SEC3 exhibit more than 97 % homology because of which specific detection tools are seldom available to identify and differentiate them. In this study, a SYBR Green-based RT-PCR followed by melt curve analysis was developed for differentiation of entC1 from entC2/entC3 using a single primer pair. Nucleotide sequences of all three subtypes were analyzed using Clustal Omega program and the region with significant sequence variation/heterogeneity (where utmost SNPs were closely located and accessible for RT-PCR) was selected for amplification by designing a single primer pair that could amplify all three subtypes. In spite of same amplicon size, entC1 showed distinct melt peak at 76 °C. However, due to high similarity between entC2 and entC3, the developed format was deficient to discriminate between them and both showed melt peak at 82 °C. Reliability of developed RT-PCR was evaluated using various naturally contaminated samples and 91 food and clinical Staphylococcus aureus isolates where satisfactory results were obtained in comparison with commercial immunoassay kit and conventional PCRs using validated primers. To the best of our knowledge, this is the first method being reported to differentiate entC1 from entC2/entC3 using single primer pair which is unachievable by conventional PCR due to same amplicon size. As benefits, the method is sensitive, rapid, and inexpensive with no requirement of fluorescent probes, multiple primers, and post-PCR procedures. Thus, the assay might find its utility as a detection tool in epidemiological survey of foodborne outbreaks for simultaneous identification and differentiation of entC1 from entC2/entC3.
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Affiliation(s)
- Sowmya Nagaraj
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, 570011, India
| | - Shylaja Ramlal
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, 570011, India.
| | | | - Soumya Paul
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, 570011, India
| | - Joseph Kingston
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, 570011, India
| | - Harsh Vardhan Batra
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, 570011, India
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Nagaraj S, Ramlal S, Kingston J, Batra HV. Thermostabilization of indigenous multiplex polymerase chain reaction reagents for detection of enterotoxigenic Staphylococcus aureus. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2016; 51:191-198. [PMID: 27260780 DOI: 10.1016/j.jmii.2016.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 04/19/2016] [Accepted: 04/25/2016] [Indexed: 11/17/2022]
Abstract
BACKGROUND/PURPOSE Among DNA-based techniques, polymerase chain reaction (PCR) is the most widely accepted molecular tool for the detection of pathogens. However, the technique involves several reagents and multiple pipetting steps that often lead to error-prone results. Additionally, the reagents entail a cold-chain facility to maintain their stability during storage and transportation. The main aim of the present study was to simplify the utility of a pre-optimized multiplex PCR format that was developed to detect toxigenic strains of Staphylococcus aureus by providing stable, pre-mixed, and ready-to-use master mix in a lyophilized formulation. METHODS Master mix containing all reagents except the template was lyophilized in the presence of an excipient lyoprotectant to achieve long-term stability without altering the sensitivity, specificity and PCR performance. Bromophenol blue was also included in the master mix to reduce the risk of external contamination during gel loading. The stability of lyophilized master mix was analyzed at different temperatures. The PCR performance was also examined after exposure of master mix to notable temperature fluctuations during transportation. RESULTS The shelf-life of lyophilized master mix was estimated to be 1.5 months at ambient temperature and 6 months at 4°C. Stability was unaffected by temperature fluctuations during transportation even in cold-chain-free conditions, thus reducing the cost required for cold storage. CONCLUSION The sensitive, cost-effective, ready-to-use, and ambient temperature stable formulation could be implemented as a detection tool in food analysis and diagnostic laboratories and hospitals and for on-field application outside the laboratories, as well as for detection of toxigenic strains of S. aureus.
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Affiliation(s)
- Sowmya Nagaraj
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India
| | - Shylaja Ramlal
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India.
| | - Joseph Kingston
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India
| | - Harsh Vardhan Batra
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India
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Nagaraj S, Ramlal S, Sripathy MH, Batra HV. Development and evaluation of a novel combinatorial selective enrichment and multiplex PCR technique for molecular detection of major virulence-associated genes of enterotoxigenic Staphylococcus aureus in food samples. J Appl Microbiol 2013; 116:435-46. [PMID: 24119042 DOI: 10.1111/jam.12364] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 09/29/2013] [Accepted: 10/01/2013] [Indexed: 11/28/2022]
Abstract
AIMS To develop a multiplex PCR assay coupled with selective enrichment step to detect major virulence-associated genes of enterotoxigenic Staphylococcus aureus and evaluate the same directly on contaminated food samples. METHODS AND RESULTS The most important virulence-associated genes of Staph. aureus, which are commonly related to food safety issues, are targeted in this study. They include five major enterotoxigenic genes-sea, seb, sec, seg and sei, tst-which encodes TSST-1, mecA-which confer methicillin resistance and coa-for the enzyme coagulase along with an internal amplification control (IAC) to rule out false-negative result. A modified mannitol salt broth (MSB) supplemented with sodium pyruvate was used for selective enrichment of Staph. aureus from food samples prior to PCR. Evaluation of efficiency of different media revealed that enrichment of samples in modified MSB followed by PCR resulted in specific, sensitive and effective amplification of the targeted genes in comparison with other enrichment media. Incorporation of bovine serum albumin (BSA) as PCR enhancer improved the intensity of amplicons. The standardized multiplex PCR (mPCR) format was able to detect all the target genes at a bacterial load of 10(6) CFU ml(-1) in any sample. The PCR results were unequivocally correlated with the conventional methods when the mPCR format was assessed on a total of 91 Staph. aureus isolates. The entire assay was found to be effectual when evaluated on naturally contaminated food samples. CONCLUSIONS The combinatorial approach involving selective enrichment followed by mPCR developed in this study was found to be effective for the detection of toxigenic Staph. aureus directly from various food sources. SIGNIFICANCE AND IMPACT OF THE STUDY The developed format would find a promising application in early detection of food contaminations as well as in the diagnosis of food poisoning due to Staph. aureus.
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Affiliation(s)
- S Nagaraj
- Microbiology Division, Defence Food Research Laboratory, Mysore, India
| | - S Ramlal
- Microbiology Division, Defence Food Research Laboratory, Mysore, India
| | - M H Sripathy
- Microbiology Division, Defence Food Research Laboratory, Mysore, India
| | - H V Batra
- Microbiology Division, Defence Food Research Laboratory, Mysore, India
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Chaivisuthangkura P, Pengsuk C, Longyant S, Sithigorngul P. Evaluation of monoclonal antibody based immunochromatographic strip test for direct detection of Vibrio cholerae O1 contamination in seafood samples. J Microbiol Methods 2013; 95:304-11. [PMID: 24060694 DOI: 10.1016/j.mimet.2013.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 09/11/2013] [Accepted: 09/12/2013] [Indexed: 10/26/2022]
Abstract
A strip test for the detection of Vibrio cholerae O1 was developed using two monoclonal antibodies (MAbs), VC-223 and VC-1226, specific to the lipopolysaccharides of Vibrio cholerae O1 Inaba and Ogawa serovars. The sensitivity of the test was 5 × 10(5)cfu/mL which was similar to that of dot blot test. The detection limit could be improved to 1cfu/mL of the original bacterial content after pre-incubation of the bacterium in alkaline peptone water (APW) for 12h. Detection of V. cholerae O1 in various fresh seafood samples such as shrimp, blood clam, mussel and oyster could be performed directly with sensitivities ranged from 5 × 10(5) to 10(6)cfu/mL. After pre-enrichment of the shrimp sample in APW, the detection sensitivities increased to 10(2) to 10CFU/mL of the original bacterial content after incubation for 12 and 24h. However, the detection sensitivities were also depending on the content of the other bacteria that might inhibit the growth of V. cholerae during pre-enrichment step. The V. cholerae O1 strip test has advantages in speed, and simplicity in not requiring sophisticated equipment or specialized skills and the sample could be directly examined without requirement for sample processing.
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Momtaz H, Dehkordi FS, Rahimi E, Asgarifar A. Detection of Escherichia coli, Salmonella species, and Vibrio cholerae in tap water and bottled drinking water in Isfahan, Iran. BMC Public Health 2013; 13:556. [PMID: 23742181 PMCID: PMC3703282 DOI: 10.1186/1471-2458-13-556] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 05/21/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The quality of drinking water has an important role in human infection and disease. This study was aimed at comparing polymerase chain reaction and culture in detecting Escherichia coli, Salmonella species and Vibrio cholera in tape water and bottled drinking water in various seasons in Isfahan province, Iran. METHODS A total of 448 water samples from tap water and bottled mineral water were taken over 6 months, from July 2010 to December 2010, and after filtration, samples were examined by culture and polymerase chain reaction methods for detection of Escherichia coli, Salmonella species, and Vibrio cholerae. RESULTS The culture method showed that 34 (7.58%), 4 (0.89%) and 3 (0.66%) of all 448 water samples were positive for Escherichia coli, Salmonella species, and Vibrio cholera, respectively. The uidA gene from Escherichia coli, IpaB gene from Salmonella species, and epsM gene from Vibrio cholera were detected in 38 (26.38%), 5 (3.47%), and 3 (2.08%) of 144 tap-water samples, respectively. Escherichia coli was detected in 8 (2.63%) of 304 samples of bottled drinking water from 5 companies. The water of southern part of Isfahan and company 5 had the highest prevalence of bacteria. The Escherichia coli water contamination was significantly higher (P < 0.05) in the hot seasons (July-August) than cold (November-December) seasons and in company 5 than other companies. There were significant differences (P < 0.05) for the prevalence of bacteria between the tap waters of southern part and tap waters of central part of Isfahan. CONCLUSIONS This study showed that the polymerase chain reaction assays can be an extremely accurate, fast, safe, sensitive and specific approach to monitor drinking water quality from purification facilities and bottled water companies. Also, our study confirmed the presence of Escherichia coli, Salmonella species, and Vibrio cholerae as water-borne pathogens in tap water and bottled drinking water of Isfahan, Iran. The present study showed the important public health problem in Isfahan, Iran.
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Affiliation(s)
- Hassan Momtaz
- Department of Microbiology, College of Veterinary Medicine, ShahreKord Branch, Islamic Azad University, P,O, Box: 166, ShahreKord, Iran.
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14
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Development and evaluation of a highly sensitive immunochromatographic strip test using gold nanoparticle for direct detection of Vibrio cholerae O139 in seafoodsamples. Biosens Bioelectron 2013. [DOI: 10.1016/j.bios.2012.10.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ahmad M, Khan AU, Wahid A, Butt ZA, Farhan M, Ahmad F. Role of Hospital Effluents in the Contribution of Antibiotics and Antibiotic Resistant Bacteria to the Aquatic Environment. ACTA ACUST UNITED AC 2012. [DOI: 10.3923/pjn.2012.1177.1182] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Hoehl MM, Lu PJ, Sims PA, Slocum AH. Rapid and robust detection methods for poison and microbial contamination. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:6349-6358. [PMID: 22630610 DOI: 10.1021/jf300817h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Real-time on-site monitoring of analytes is currently in high demand for food contamination, water, medicines, and ingestible household products that were never tested appropriately. Here we introduce chemical methods for the rapid quantification of a wide range of chemical and microbial contaminations using a simple instrument. Within the testing procedure, we used a multichannel, multisample, UV-vis spectrophotometer/fluorometer that employs two frequencies of light simultaneously to interrogate the sample. We present new enzyme- and dye-based methods to detect (di)ethylene glycol in consumables above 0.1 wt % without interference and alcohols above 1 ppb. Using DNA intercalating dyes, we can detect a range of pathogens ( E. coli , Salmonella , V. Cholera, and a model for Malaria) in water, foods, and blood without background signal. We achieved universal scaling independent of pathogen size above 10(4) CFU/mL by taking advantage of the simultaneous measurement at multiple wavelengths. We can detect contaminants directly, without separation, purification, concentration, or incubation. Our chemistry is stable to ± 1% for >3 weeks without refrigeration, and measurements require <5 min.
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Affiliation(s)
- Melanie M Hoehl
- Department of Mechanical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, USA.
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17
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Usachev EV, Agranovski IE. Internally controlled PCR system for detection of airborne microorganisms. ACTA ACUST UNITED AC 2012; 14:1631-7. [DOI: 10.1039/c2em30019b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Pengsuk C, Longyant S, Rukpratanporn S, Chaivisuthangkura P, Sridulyakul P, Sithigorngul P. Differentiation among the Vibrio cholerae serotypes O1, O139, O141 and non-O1, non-O139, non-O141 using specific monoclonal antibodies with dot blotting. J Microbiol Methods 2011; 87:224-33. [PMID: 21851839 DOI: 10.1016/j.mimet.2011.07.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/27/2011] [Accepted: 07/28/2011] [Indexed: 10/17/2022]
Abstract
Seven different monoclonal antibodies (MAbs) specific to only Vibrio cholerae were produced using a combination of five representative serotypes of V. cholerae for immunization. The first three MAbs (VC-93, VC-82 and VC-223) were specific to the V. cholerae serogroup O1 with different avidity for the serotypes O1 Inaba and O1 Ogawa. The fourth and the fifth MAbs were specific to V. cholerae O139 (VC-812) or O141 (VC-191) serogroups, respectively. The sixth MAb (VC-26) bound to all three serogroups of V. cholerae. The seventh MAb (VC-63) bound to all twenty five isolates of V. cholerae used in this study. None of the seven MAbs showed cross-reactivity with other Vibrio spp. or closely-related V. cholerae species, V. mimicus or other gram-negative bacteria. The eighth MAbs (VC-201) specific to almost all Vibrio spp. was also obtained. In dot blotting, these MAbs can be used to detect a diluted pure culture of V. cholerae in solution with a sensitivity range of from 10(5) to 10(7) CFU ml(-1). However, the detection capability could be improved equivalent to that of PCR technique after preincubation of samples in alkaline peptone water (APW). Thus, these MAbs constitute convenient immunological tools that can be used for simple, rapid and simultaneous direct detection and differentiation of the individual serotypes of V. cholerae in complex samples, such as food and infected animals, without the requirement for bacterial isolation or biochemical characterization.
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Affiliation(s)
- Chalinan Pengsuk
- Department of Biology, Srinakharinwirot University, Bangkok 10110, Thailand
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Jeyasekaran G, Raj KT, Shakila RJ, Thangarani AJ, Sukumar D. Multiplex polymerase chain reaction-based assay for the specific detection of toxin-producing Vibrio cholerae in fish and fishery products. Appl Microbiol Biotechnol 2011; 90:1111-8. [PMID: 21360148 DOI: 10.1007/s00253-011-3175-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 02/04/2011] [Accepted: 02/06/2011] [Indexed: 10/18/2022]
Abstract
A multiplex polymerase chain reaction (MPCR)-based assay was developed for the simultaneous detection of Vibrios using the genus-specific RNA polymerase subunit A (rpoA) gene and specific detection of toxin-producing Vibrio cholerae strains using two sets of primer based on cholera toxin subunit A (ctxA) and repeat in toxin subunit A (RtxA)-producing genes. The MPCR method developed is applicable to both the simultaneous and the two-step detection of genus Vibrio total and toxigenic V. cholerae species. This assay was specific as no amplification occurred with the other bacterial pathogens tested. The sensitivity of the assay was tested by artificially spiking the shrimp homogenate with the toxigenic strain of V. cholerae (NICED 16582) in different dilutions. The developed MPCR assay could detect three cells of V. cholerae in 12 h pre-enrichment in APW. The proposed method is rapid, sensitive, and specific for the detection of Vibrio genus as well as toxin-producing V. cholerae strains in environmental samples.
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Affiliation(s)
- Geevaretnam Jeyasekaran
- Department of Fish Processing Technology, Fisheries College and Research Institute, Tamil Nadu Veterinary and Animal Sciences University, Tuticorin 628 008, India.
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Theron J, Eugene Cloete T, de Kwaadsteniet M. Current molecular and emerging nanobiotechnology approaches for the detection of microbial pathogens. Crit Rev Microbiol 2010; 36:318-39. [DOI: 10.3109/1040841x.2010.489892] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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21
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Mendes CL, Abath FGC, Leal NC. Development of a multiplex single-tube nested PCR (MSTNPCR) assay for Vibrio cholerae O1 detection. J Microbiol Methods 2007; 72:191-6. [PMID: 18191489 DOI: 10.1016/j.mimet.2007.11.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 11/12/2007] [Accepted: 11/27/2007] [Indexed: 10/22/2022]
Abstract
A multiplex nested PCR method for detection of Vibrio cholerae O1 using a single tube was developed (MSTNPCR). Firstly, single-tube nested PCR (STNPCR) with primers directed to ctxA gene was standardized, and its detection limit was compared to simple PCR and two-step nested PCR. Secondly, primers directed to rfbN gene were added to the reaction. The detection limit of the multiplex reaction was determined using V. cholerae O1 DNA and V. cholerae O1 grown in alkaline peptone water (APW). STNPCR was shown to be approximately 100-fold more sensitive than simple PCR and 10 times less sensitive than two-step nested PCR. This drawback is compensated by a lower risk of cross-contamination. The addition of a second target did not impair the detection limit of STNPCR (as little as 1 pg of V. cholerae O1 DNA detected). MSTNPCR could specifically detect up to three V. cholerae O1 cells or colony forming units (cfu) directly from the APW growth. A diagnostic kit consisting of a set of microtubes having the inner primers fixed onto the inside of the tube cap and a set of tubes containing the reaction mixture was evaluated for stability, and it proved to be stable for five months at -20 degrees C. Therefore, MSTNPCR would be useful in the detection of V. cholerae O1 directly from environmental waters in cholera endemic areas and in complementing the identification of toxigenic strains isolated by culture.
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Affiliation(s)
- Carina Lucena Mendes
- Departamento de Microbiologia, Centro de Pesquisas Aggeu Magalhães, Fiocruz, Avenida Prof. Moraes Rego, s/n, Campus da UFPE, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil.
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Chomvarin C, Namwat W, Wongwajana S, Alam M, Thaew-Nonngiew K, Sinchaturus A, Engchanil C. Application of duplex-PCR in rapid and reliable detection of toxigenic Vibrio cholerae in water samples in Thailand. J GEN APPL MICROBIOL 2007; 53:229-37. [PMID: 17878662 DOI: 10.2323/jgam.53.229] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Toxigenic Vibrio cholerae, the cause of cholera, is a native flora of the aquatic environment which is transmitted through drinking water and still remains the leading cause of morbidity and mortality in many developing countries including Thailand. The culture method (CM), which is routinely used for assessing water quality, has not proven as efficient as molecular methods because the notorious pathogen survives in water mostly in a non-culturable state. We employed duplex-polymerase chain reaction (duplex-PCR) for detection of tcpA and ctxA genes in toxigenic V. cholerae, and compared PCR detection with CM in various waters of Khon Kaen Municipality, Thailand. We also evaluated the effect of different pre-PCR conditions on the results of ctxA and tcpA detection including: 1) water filtered and enriched in alkaline peptone water (APW) for 3 h before PCR, 2) water filtered without enrichment before PCR, and 3) use of only enrichment in APW for 6 h before PCR. Of the 96 water samples (taken from waste-water, potable and waste-water from patients' houses, and from rivers) tested, 48 (50%) were positive for ctxA and tcpA by duplex-PCR, whereas only 29 (30%) were positive for V. cholerae by CM. Of the 29 V. cholerae isolated by CM, 2 (7%) were toxigenic V. cholerae belonging to serovar O1, while the rests were non-O1/ non-O139. Results revealed, therefore, that ctxA and tcpA-targeted duplex PCR is more sensitive than CM for detection of toxigenic V. cholerae from water samples because CM detected much less toxigenic V. cholerae than the non-toxigenic V. cholerae. Template DNA as low as 100 fg or 23 cells of V. cholerae in the water sample was detected in duplex PCR. Pre-PCR filtration followed by enrichment for 3 h significantly increase in the efficiency of duplex-PCR detection of toxigenic V. cholerae.
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Affiliation(s)
- Chariya Chomvarin
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Thailand.
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Goel AK, Bhadauria S, Kumar P, Kamboj DV, Singh L. Semi-nested polymerase chain reaction for detection of toxigenic Vibrio cholerae from environmental water samples. Indian J Microbiol 2007; 47:207-11. [PMID: 23100668 DOI: 10.1007/s12088-007-0041-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 06/11/2007] [Accepted: 07/05/2007] [Indexed: 01/17/2023] Open
Abstract
A rapid and sensitive direct cell semi-nested PCR assay was developed for the detection of viable toxigenic V. cholerae in environmental water samples. The semi-nested PCR assay amplified cholera toxin (ctxA2B) gene present in the toxigenic V. cholerae. The detection sensitivity of direct cell semi-nested PCR was 2 × 10(3) CFU of V. cholerae whereas direct cell single-step PCR could detect 2 × 10(4) CFU of V. cholerae. The performance of the assay was evaluated using environmental water samples after spiking with known number of Vibrio cholerae O1. The spiked water samples were filtered through a 0.22 micrometer membrane and the bacteria retained on filters were enriched in alkaline peptone water and then used directly in the PCR assay. The semi-nested PCR procedure coupled with enrichment could detect less than 1 CFU/ml in ground water and sea water whereas 2 CFU/ml and 20 CFU/ml could be detected in pond water and tap water, respectively. The proposed method is simple, faster than the conventional detection assays and can be used for screening of drinking water or environmental water samples for the presence of toxigenic V. cholerae.
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Affiliation(s)
- Ajay Kumar Goel
- Biotechnology Division, Defence Research & Development Establishment, Gwalior, 474 002 (M.P.) India
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Lazcka O, Del Campo FJ, Muñoz FX. Pathogen detection: A perspective of traditional methods and biosensors. Biosens Bioelectron 2007; 22:1205-17. [PMID: 16934970 DOI: 10.1016/j.bios.2006.06.036] [Citation(s) in RCA: 835] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 05/15/2006] [Accepted: 06/30/2006] [Indexed: 11/26/2022]
Abstract
The detection of pathogenic bacteria is key to the prevention and identification of problems related to health and safety. Legislation is particularly tough in areas such as the food industry, where failure to detect an infection may have terrible consequences. In spite of the real need for obtaining analytical results in the shortest time possible, traditional and standard bacterial detection methods may take up to 7 or 8 days to yield an answer. This is clearly insufficient, and many researchers have recently geared their efforts towards the development of rapid methods. The advent of new technologies, namely biosensors, has brought in new and promising approaches. However, much research and development work is still needed before biosensors become a real and trustworthy alternative. This review not only offers an overview of trends in the area of pathogen detection but it also describes main techniques, traditional methods, and recent developments in the field of pathogen bacteria biosensors.
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Affiliation(s)
- Olivier Lazcka
- Instituto de Microelectrónica de Barcelona (IMB-CNM), CSIC, Campus Universitat Autónoma de Barcelona, Barcelona 08193, Spain
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Gubala AJ, Proll DF. Molecular-beacon multiplex real-time PCR assay for detection of Vibrio cholerae. Appl Environ Microbiol 2006; 72:6424-8. [PMID: 16957277 PMCID: PMC1563670 DOI: 10.1128/aem.02597-05] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A multiplex real-time PCR assay was developed using molecular beacons for the detection of Vibrio cholerae by targeting four important virulence and regulatory genes. The specificity and sensitivity of this assay, when tested with pure culture and spiked environmental water samples, were high, surpassing those of currently published PCR assays for the detection of this organism.
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Affiliation(s)
- Aneta J Gubala
- Human Protection and Performance Division, Defence Science and Technology Organisation, Melbourne, Australia.
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Ahn-Yoon S, DeCory TR, Baeumner AJ, Durst RA. Ganglioside-liposome immunoassay for the ultrasensitive detection of cholera toxin. Anal Chem 2003; 75:2256-61. [PMID: 12918964 DOI: 10.1021/ac026428t] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An extremely sensitive bioassay has been developed for cholera toxin (CT) detection, using ganglioside-incorporated liposomes. Cholera is a diarrheal disease, often associated with water or seafood contamination. Ganglioside GM1 was used to prepare the liposomes by spontaneous insertion into the phospholipid bilayer. CT recognition and signal generation is based on the strong and specific interaction between GM1 and CT. In a sandwich immunoassay, CT was detected as a colored band on the nitrocellulose membrane strip, where CT bound to GM1-liposomes can be captured by immobilized antibodies. The intensity of the band could be visually estimated or measured by densitometry, using computer software. The limit of detection (LOD) of CT in the assay system was found to be 10 fg/mL which is equivalent to 8 zmol in the 70-microL sample. The assay was also tested with water samples spiked with CT, providing a LOD of 0.1-30 pg/mL, which is much better than previously reported limits of detection from other assays. The assay could be completed within 20 min. These results demonstrate that the bioassay developed for CT is rapid and ultrasensitive, suggesting the possibility for detecting CT, simply and reliably, in field screening.
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Affiliation(s)
- Soohyoun Ahn-Yoon
- Department of Food Science & Technology, Cornell University, Geneva, New York 14456-0462, USA
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Theron J, Cloete TE. Emerging waterborne infections: contributing factors, agents, and detection tools. Crit Rev Microbiol 2002; 28:1-26. [PMID: 12003038 DOI: 10.1080/1040-840291046669] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Because microorganisms are easily dispersed, display physiological diversity, and tolerate extreme conditions, they are ubiquitous and may contaminate and grow in water. The presence of waterborne enteric pathogens (bacteria, viruses, and protozoa) in domestic water supplies represents a potentially significant human health risk. Even though major outbreaks of waterborne disease are comparatively rare, there is substantial evidence that human enteric pathogens that are frequently present in domestic water supplies are responsible for low-level incidence of waterborne microbial disease. Although these diseases are rarely debilitating to healthy adults for more than a few hours to a few days, enteric pathogens can cause severe illness, even death, for young children, the elderly, or those with compromised immune systems. As the epidemiology of waterborne diseases is changing, there is a growing global public health concern about new and reemerging infectious diseases that are occurring through a complex interaction of social, economic, evolutionary, and ecological factors. New microbial pathogens have emerged, and some have spread worldwide. Alternative testing strategies for waterborne diseases should significantly improve the ability to detect and control the causative pathogenic agents. In this article, we provide an overview of the current state of knowledge of waterborne microbial pathogens, their detection, and the future of new methods in controlling these infectious agents.
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Affiliation(s)
- J Theron
- Department of Microbiology and Plant Pathology, University of Pretoria, South Africa
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Abstract
Cholera continues to be an important public health problem among many poorer communities in Africa, Asia and South America, despite the bacteriology and epidemiology of the disease having been described over a century ago. Molecular techniques have enabled current researchers to gain new insights into pathogenicity, into the relationships between environmental and clinical strains, and into new strategies for vaccine development. The description of non-culturable 'dormant' strains in the environment and the effect of environmental factors on toxin gene regulation provide valuable clues to the ecology of the disease. Disease management continues to be based on urgent and appropriate rehydration, and recent community studies emphasize the need for effective local health services to provide this if case fatality rates are to remain low. While antimicrobial agents may play a role in case management and prophylaxis, the increasing prevalence of antimicrobial resistance must be addressed. New vaccine candidates, based on a molecular understanding of pathogenicity, provide scope for improved strategies for disease prevention, though the appropriate public health context for their use has not been determined. This review summarizes activities in these fields of cholera research and considers the continuing global problem of the disease.
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Affiliation(s)
- P Shears
- Centre for Tropical Medical Microbiology, Liverpool School of Tropical Medicine, Liverpool, UK.
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Lyon WJ. TaqMan PCR for detection of Vibrio cholerae O1, O139, non-O1, and non-O139 in pure cultures, raw oysters, and synthetic seawater. Appl Environ Microbiol 2001; 67:4685-93. [PMID: 11571173 PMCID: PMC93220 DOI: 10.1128/aem.67.10.4685-4693.2001] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Vibrio cholerae is recognized as a leading human waterborne pathogen. Traditional diagnostic testing for Vibrio is not always reliable, because this bacterium can enter a viable but nonculturable state. Therefore, nucleic acid-based tests have emerged as a useful alternative to traditional enrichment testing. In this article, a TaqMan PCR assay is presented for quantitative detection of V. cholerae in pure cultures, oysters, and synthetic seawater. Primers and probe were designed from the nonclassical hemolysin (hlyA) sequence of V. cholerae strains. This probe was applied to DNA from 60 bacterial strains comprising 21 genera. The TaqMan PCR assay was positive for all of the strains of V. cholerae tested and negative for all other species of Vibrio tested. In addition, none of the other genera tested was amplified with the TaqMan primers and probe used in this study. The results of the TaqMan PCR with raw oysters and spiked with V. cholerae serotypes O1 and O139 were comparable to those of pure cultures. The sensitivity of the assay was in the range of 6 to 8 CFU g(-1) and 10 CFU ml(-1) in spiked raw oyster and synthetic seawater samples, respectively. The total assay could be completed in 3 h. Quantification of the Vibrio cells was linear over at least 6 log units. The TaqMan probe and primer set developed in this study can be used as a rapid screening tool for the presence of V. cholerae in oysters and seawater without prior isolation and characterization of the bacteria by traditional microbiological methods.
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Affiliation(s)
- W J Lyon
- Rapid Microbial Detection Facility, Department of Food Science, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA.
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