Specificity of the BAX Polymerase Chain Reaction System for Detection of the Foodborne Pathogen Listeria monocytogenes

1998 ◽  
Vol 81 (4) ◽  
pp. 817-822 ◽  
Author(s):  
Diana Stewart ◽  
Steven M Gendel

Abstract The polymerase chain reaction (PCR) can be used for rapid and specific detection of foodborne pathogens. One commercial kit, the Qualicon BAX system uses PCR to detect Listeria monocytogenes in enrichment cultures derived from food and environmental samples. The specificity and sensitivity of the BAX system for detecting L. monocytogenes were characterized by using both pure and mixed cell cultures, and optimal conditions for production of cell lysates were determined. The BAX system was highly specific for L. monocytogenes, and no interference was seen in the presence of either other Listeria species or microbes from other genera. The assay detected L. monocytogenes at 105- 106 colony-forming units/mL. This sensitivity is adequate for detecting viable cells after enrichment but prevents false-positive signals from nonviable cells.

2003 ◽  
Vol 66 (3) ◽  
pp. 436-440 ◽  
Author(s):  
JASON WAN ◽  
KERRYN KING ◽  
SANTINA FORSYTH ◽  
M. JOHN COVENTRY

A validation was conducted on the performance of a commercially available polymerase chain reaction (PCR) kit (Probelia) in comparison with International Organization for Standardization (ISO) method 11290-1 (adopted as an Australian New Zealand Standard Method, AS/NZS 1766.2.16.1:1998) for the detection of Listeria monocytogenes in salmon samples. The validation was conducted following the guidelines of an Australian New Zealand Standard (Guide to Determining the Equivalence of Food Microbiology Test Methods, Part 1, Qualitative Tests, AS/NZS 4659.1:1999), which adopts an approach similar to that recommended by the Association of Analytical Communities Microbiology Method Validation Program for Performance Tested and Peer Verified Methods. The validation study involved the use of five cultures of L. monocytogenes, each challenged at a single level of inoculation into five different types of salmon samples. A total of 60 salmon samples (30 unchallenged and 30 challenged) were tested using both the PCR method and the ISO method. Results from this study indicated that the Probelia PCR method is equivalent to the ISO method. In addition, the detection sensitivity of the Probelia PCR system was determined as approximately 0.5 CFU per PCR assay (equivalent to 20 CFU/ml broth culture) for a pure culture of L. monocytogenes. The Probelia PCR method offers the advantage of detecting L. monocytogenes to genetic specificity within 48 to 50 h, whereas the ISO method requires 5 days for negative results with additional days for confirmed positive results by the use of other biochemical and cultural tests.


2011 ◽  
Vol 27 (3) ◽  
pp. 357-364
Author(s):  
B. T. Chia ◽  
S.-A. Yang ◽  
M.-Y. Cheng ◽  
C.-W. Lin ◽  
Y.-J. Yang

ABSTRACTIn this paper, the development of a portable polymerase chain reaction (PCR) device is presented. Integrating electromagnetic mini-actuators for bi-directional fluid transport, the proposed device, whose dimension is 67mm × 66mm × 25mm, can be fully operated with a 5V DC voltage. The device consists of four major parts: A disposable channel chip in which PCR mixture is manipulated and reacted, a heater chip which generates different temperature zones for PCR reaction, a linear actuator array for pumping PCR mixture, and a circuit module for controlling and driving the system. The advantages of the device include the rapid temperature responses associated with continuous-flow-type PCR devices, as well as the programmable thermal cycling associated with chamber-type PCR devices. The thermal characteristics are measured and discussed. PCR amplification is successfully performed for the 122 bp segment of MCF-7/adr cell line. Due to its small footprint, this self-contained system potentially can be employed for point-of-care (POC) applications.


1995 ◽  
Vol 12 (2) ◽  
pp. 135-140
Author(s):  
Akiko NAKAMA ◽  
Seiji KANEKO ◽  
Fujio UMEKI ◽  
Takeshi ITOH ◽  
Yataro KOKUBO ◽  
...  

Author(s):  
María Fernanda Calderón Hernádez ◽  

Background: The main objective of this research is to learn the symptoms that occur in this pathology, since we are currently still fighting COVID-19, because of this, it is important to keep us informed about the different diagnostic methods available, which help us reach an earlier and more effective diagnosis. Various articles have been compiled to identify as soon as possible the active cases and thus reduce the number of infections. Materials and methods: This research was conducted on the basis of scientific articles and books, related to COVID-19. Methods: This research was conducted based on 15 scientific articles and 3 books, related to COVID-19. Results: The most important risk factors are diabetes mellitus, hypertension, obesity, age and sex. The most common symptoms in Latin America are dry cough, fatigue, sore throat, and fever. The preferred diagnostic test for COVID-19 is the polymerase chain reaction for its specificity and sensitivity Conclusions: As a conclusion, the main objective of the research was achieved, which is to inform the reader about the most relevant symptoms of SARS-CoV-2 in order to improve the identification of suspected cases. Furthermore, we compare various diagnostic methods that exist to date and determine that PCR is the most specific and sensitive.


2021 ◽  
pp. 2878-2882
Author(s):  
Sirikanda Thanasuwan ◽  
Anupong Tankrathok

Background and Aim: Fasciola spp. are important foodborne trematodes and waterborne zoonotic parasites that cause health problems and economic losses worldwide, including in Thailand. Fasciola spp. are usually detected by sedimentation or the formalin-ethyl acetate concentration technique (FECT) under microscopy, which is less specific and sensitive. Accurate detection is important to detect real incidence for protection against and elimination of fasciolosis in the area. This study aimed to determine the distribution of Fasciola spp. and compare the specificity and sensitivity of FECT under microscopy to that of polymerase chain reaction (PCR) in cattle feces. Materials and Methods: The study was conducted in Kalasin Province, Thailand. Feces of 46 cattle were investigated for infection with Fasciola spp. To detect infection, FECT under microscopy and PCR amplification of the 28S rRNA gene of Fasciola spp. were used to identify egg parasites. Results: Feces of 16 of 46 (34.78%) cattle were positive for Fasciola spp. using FECT under microscopy, whereas PCR showed that 67.39% (31 of 46) were positive for Fasciola spp. False-negative results were as high as 32.61% when diagnosed under microscopy. Conclusion: This study confirmed the infection of cattle with Fasciola spp. in Kalasin Province, indicating that PCR demonstrated higher sensitivity and specificity when diagnosing infection. FECT under microscopy can still be used as a primary and traditional method for diagnosis. However, relapse cases of Fasciola spp. and Paramphistomum spp. should be diagnosed by microscopy combined with PCR. This is the first report on the molecular distribution of fecal samples in cattle in Kalasin Province.


2011 ◽  
Vol 1 (1) ◽  
pp. 45
Author(s):  
Muktiningsih Nurjayadi ◽  
Fera Kurnia Dewi ◽  
Dahlia Dahlia ◽  
S, Restu.N S ◽  
Fitri W

Salmonella typhi is bacteria that cause typhoid disease in humans. In Indonesia, the morbidity number of typhoid disease tends to be increase. Thus, it has been requiring the alternative for handling or preventing that disease. Recently, the detection method commonly uses for S. typhi detection is Serological test. The weakness of this method is often producing less accurate and not specific detection. The previous research was successfully discovered S. typhi gene that codes protein which is contributed at adherents or colonization those bacteria in epithelial human cell. That result was base to develop detection on S. typhi method by Polymerase chain reaction (PCR). The aim of this research is developing a specific and accurate detection method for S. typhi bacteria by PCR. The research result is performed successfully to amplify the fimbrial-C S. typhi gene using pairs of primer FW-INT 2- REV-1A NEW which was designed and synthesized in previous step. That success showed by the finding of the DNA fragment of 0.2 kilobase (kb) proffers to size of DNA fragment which is hopefully in using S. typhi genome as a template. Specificity and sensitivity test for those primers are still conducting to reproducibility results. Base on the results can be concluded that the research have successfully conducted in developing S. typhi detection method using pairs of S. typhi fimbrial-C primer. Hopefully, the studied of developing detection methods was conducted better compare with former detection methods.Keywords: S. typhi detection method, fim-C S. typhi gene, PCRAbstrakSalmonella typhi merupakan bakteri penyebab penyakit tifus pada manusia. Di Indonesia, angka morbiditas penderita penyakit typhus cenderung meningkat, sehingga diperlukan suatu alternatif untuk penanganan atau pencegahan penyakit tersebut. Sampai saat ini metode deteksi S. typhi yang banyak digunakan adalah uji serologi. Kelemahan metode ini adalah sering menghasilkan deteksi yang kurang akurat dan tidak spesifik. Pada penelitian yang dilakukan sebelumnya, telah berhasil ditemukan gen fimbrial-C S. typhi pengkode protein yang berperan dalam penempelan S. typhi pada usus manusia, hasil ini dijadikan landasan untuk pengembangan metode deteksi menggunakan teknik PCR. Tujuan penelitian ini mengembangkan metode deteksi yang akurat dan spesifik untuk bakteri penyebab penyakit typhus pada manusia. Hasil penelitian menunjukkan bahwa telah berhasil dilakukan amplifikasi gen fimbrial-C S. typhi menggunakan pasangan primer hasil perancangan yaitu FW-INT 2- REV-1A NEW. Keberhasilan tersebut ditunjukkan dengan diperolehnya pita DNA berukuran 0.2 kilo basa (kb) sesuai dengan ukuran pita DNA yang diharapkan dengan menggunakan template DNA genom bakteri S. typhi. Uji sensitivitas dan spesifisitas terhadap primer hasil rancangan sedang di kaji lebih lanjut untuk memperoleh reprodusibiltas hasil pengujian. Berdasarkan hasil yang diperoleh dapat disimpulkan bahwa telah berhasil dilakukan pengembangan metode deteksi S. typhi menggunakan pasangan primer fimbrial-C S. typhi. Pengkajian pengembangan metode deteksi yang dihasilkan ini diharapkan dapat lebih baik dibanding beberapa metode deteksi yang sudah ada.Kata Kunci: Metode Deteksi Bakteri typhus, fim-C S. typhi, PCR


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