scholarly journals SYBR Green Real-Time PCR Assay for Detection of the Indicator Bacillus cereus to Validate Thermal Processing of Tender Coconut Water

2019 ◽  
Vol 13 (3) ◽  
pp. 1325-1334
Author(s):  
Jayaprahash C ◽  
Siva Ramakrishna U ◽  
Joseph Kingston J
2007 ◽  
Vol 73 (6) ◽  
pp. 1892-1898 ◽  
Author(s):  
Martina Fricker ◽  
Ute Messelhäußer ◽  
Ulrich Busch ◽  
Siegfried Scherer ◽  
Monika Ehling-Schulz

ABSTRACT Cereulide-producing Bacillus cereus can cause an emetic type of food-borne disease that mimics the symptoms provoked by Staphylococcus aureus. Based on the recently discovered genetic background for cereulide formation, a novel 5′ nuclease (TaqMan) real-time PCR assay was developed to provide a rapid and sensitive method for the specific detection of emetic B. cereus in food. The TaqMan assay includes an internal amplification control and primers and a probe designed to target a highly specific part of the cereulide synthetase genes. Additionally, a specific SYBR green I assay was developed and extended to create a duplex SYBR green I assay for the one-step identification and discrimination of the two emesis-causing food pathogens B. cereus and S. aureus. The inclusivity and exclusivity of the assay were assessed using a panel of 100 strains, including 23 emetic B. cereus and 14 S. aureus strains. Different methods for DNA isolation from artificially contaminated foods were evaluated, and established real-time assays were used to analyze two recent emetic food poisonings in southern Germany. One of the food-borne outbreaks included 17 children visiting a day care center who vomited after consuming a reheated rice dish, collapsed, and were hospitalized; the other case concerned a single food-poisoning incident occurring after consumption of cauliflower. Within 2 h, the etiological agent of these food poisonings was identified as emetic B. cereus by using the real-time PCR assay.


2007 ◽  
Vol 70 (12) ◽  
pp. 2774-2781 ◽  
Author(s):  
I-CHEN YANG ◽  
DANIEL YANG-CHIH SHIH ◽  
JAN-YI WANG ◽  
TZU-MING PAN

Members of the Bacillus cereus group may produce diarrheal enterotoxins and could be potential hazards if they enter the food chain. Therefore, a method capable of detecting all the species in the B. cereus group rather than B. cereus alone is important. We selected nhe as the target and developed a real-time PCR assay to quantify enterotoxigenic strains of the B. cereus group. The real-time PCR assay was evaluated with 60 B. cereus group strains and 28 others. The assay was also used to construct calibration curves for different food matrices and feces. The assay has an excellent quantification capacity, as proved by its linearity (R2 > 0.993), wide dynamic quantification range (102 to 107 CFU/g for cooked rice and chicken, 103 to 107 CFU/ml for milk, and 104 to 107 CFU/g for feces), and adequate relative accuracy (85.5 to 101.1%). For the low-level contaminations, a most-probable-number real-time PCR assay was developed that could detect as low as 100 CFU/ml. Both assays were tested with real food samples and shown to be considerably appropriate for B. cereus group detection and quantification.


2007 ◽  
Vol 21 (5-6) ◽  
pp. 368-378 ◽  
Author(s):  
Anna Casabianca ◽  
Caterina Gori ◽  
Chiara Orlandi ◽  
Federica Forbici ◽  
Carlo Federico Perno ◽  
...  

2020 ◽  
Vol 119 (11) ◽  
pp. 3909-3913
Author(s):  
Zaida Rentería-Solís ◽  
Tran Nguyen-Ho-Bao ◽  
Shahinaz Taha ◽  
Arwid Daugschies

Abstract Trichomonas gallinae are parasitic flagellates of importance in wild and domestic birds. The parasite is worldwide distributed, and Columbine birds are its main host. Current research focuses mostly on epidemiological and phylogenetic studies. However, there is still a lack of knowledge regarding parasite-host interaction or therapy development. Real-time PCR is a useful tool for diagnostic and quantification of gene copies in a determined sample. By amplification of a 113-bp region of the 18S small subunit ribosomal RNA gene, a SYBR green-based real-time PCR assay was developed. A standard curve was prepared for quantification analysis. Assay efficiency, linearity, and dissociation analysis were successfully performed. Specificity, sensibility, and reproducibility analysis were tested. This assay could be a useful tool not only for diagnostic purposes but also for future in vivo and in vitro T. gallinae studies.


2011 ◽  
Vol 60 (4) ◽  
pp. 459-466 ◽  
Author(s):  
Spencer D. Polley ◽  
Samuel Boadi ◽  
Julie Watson ◽  
Alan Curry ◽  
Peter L. Chiodini

Diagnosis of microsporidial infections is routinely performed by light microscopy, with unequivocal non-molecular species identification achievable only through electron microscopy. This study describes a single SYBR Green real-time PCR assay for the simultaneous detection and species identification of such infections. This assay was highly sensitive, routinely detecting infections containing 400 parasites (g stool sample)−1, whilst species identification was achieved by differential melt curves on a Corbett Life Science Rotor-Gene 3000. A modification of the QIAamp DNA tissue extraction protocol allowed the semi-automated extraction of DNA from stools for the routine diagnosis of microsporidial infection by real-time PCR. Of 168 stool samples routinely analysed for microsporidian spores, only five were positive by microscopy. By comparison, 17 were positive for microsporidial DNA by real-time analysis, comprising 14 Enterocytozoon bieneusi, one Encephalitozoon cuniculi and two separate Pleistophora species infections.


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