Application of sonication to release DNA from Bacillus cereus for quantitative detection by real-time PCR

2003 ◽  
Vol 55 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Else Marie Fykse ◽  
Jaran Strand Olsen ◽  
Gunnar Skogan
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.


2005 ◽  
Vol 71 (7) ◽  
pp. 3911-3916 ◽  
Author(s):  
Mark G. Wise ◽  
Gregory R. Siragusa

ABSTRACT Strains of Clostridium perfringens are a frequent cause of food-borne disease and gas gangrene and are also associated with necrotic enteritis in chickens. To detect and quantify the levels of C. perfringens in the chicken gastrointestinal tract, a quantitative real-time PCR assay utilizing a fluorogenic, hydrolysis-type probe was developed and utilized to assay material retrieved from the broiler chicken cecum and ileum. Primers and probe were selected following an alignment of 16S rDNA sequences from members of cluster I of the genus Clostridium, and proved to be specific for C. perfringens. The assay could detect approximately 50 fg of C. perfringens genomic DNA and approximately 20 cells in pure culture. Measurements of the analytical sensitivity determined with spiked intestinal contents indicated that the consistent limit of detection with ileal samples was approximately 102 CFU/g of ileal material, but only about 104 CFU/g of cecal samples. The decreased sensitivity with the cecal samples was due to the presence of an unidentified chemical PCR inhibitor(s) in the cecal DNA purifications. The assay was utilized to rapidly detect and quantify C. perfringens levels in the gut tract of broiler chickens reared without supplementary growth-promoting antibiotics that manifested symptoms of necrotic enteritis. The results illustrated that quantitative real-time PCR correlates well with quantification via standard plate counts in samples taken from the ileal region of the gastrointestinal tract.


2005 ◽  
Vol 68 (6) ◽  
pp. 1217-1221 ◽  
Author(s):  
PAVEL KRCMAR ◽  
EVA RENCOVA

A sensitive and rapid method for the quantitative detection of bovine-, ovine-, swine-, and chicken-specific mitochondrial DNA sequences based on real-time PCR has been developed. The specificity of the primers and probes for real-time PCR has been tested using DNA samples of other vertebrate species that may also be present in rendered products. The quantitative detection was performed with dual-labeled probes (TaqMan) using absolute quantification with external standards of single species meat-and-bone meals. This method facilitates the detection of 0.01% of the target species–derived material in concentrate feed mixtures and fish meals.


2003 ◽  
Vol 38 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Chengbo Yang ◽  
Yuan Jiang ◽  
Kehe Huang ◽  
Changqing Zhu ◽  
Yulong Yin

2004 ◽  
Vol 8 (3) ◽  
pp. 179-184 ◽  
Author(s):  
Nobuyuki Hinata ◽  
Toshiro Shirakawa ◽  
Hiroshi Okada ◽  
Katsumi Shigemura ◽  
Sadao Kamidono ◽  
...  

2012 ◽  
Vol 95 (6) ◽  
pp. 1652-1655 ◽  
Author(s):  
Rakesh Kumar ◽  
K V Lalitha

Abstract A non-radio-labeled probe-based detection method was developed for rapid enumeration of Salmonella in seafood and water samples. A Salmonella-specific invA gene probe was developed using a digoxigenin-based non-radio labeling assay, which was evaluated with naturally contaminated seafood and water samples. The probe-based technique was further compared with the quantitative PCR assay. The method was specific for detection of different Salmonella serovars without any nonspecific hybridization with other Salmonella-related Enterobacteriaceae. The optimum labeling efficiency was determined for the labeled probe, and 10 pg/μL probe concentration was observed to be most efficient for detection of Salmonella colonies on nylon membrane. Quantification of Salmonella in naturally contaminated seafood and water samples (n = 21) was in the range 10–102 CFU/mL. The assay successfully quantified Salmonella in spiked seafood and water samples in the presence of background flora, and the entire assay was completed within 48 h. The probe-based assay was further evaluated with real-time PCR, and results showed that the assay was comparable to real-time PCR assay. Thus, this probe-based assay can be a rapid, useful, and alternative technique for quantitative detection of Salmonella in food, feed, and water samples.


Sign in / Sign up

Export Citation Format

Share Document