Development of Two Multiplex Polymerase Chain Reactions for the Detection of Enterotoxigenic Strains of Staphylococcus aureus Isolated from Foods

2003 ◽  
Vol 66 (6) ◽  
pp. 1055-1062 ◽  
Author(s):  
GABRIELA NÁJERA-SÁNCHEZ ◽  
ROGELIO MALDONADO-RODRÍGUEZ ◽  
PATRICIA RUÍZ OLVERA ◽  
LYDIA MOTA de la GARZA
Keyword(s):  
Staphylococcus Aureus ◽  
Simultaneous Detection ◽  
Type A ◽  
Enzyme Linked Immunosorbent Assay ◽  
Powdered Milk ◽  
Chain Reactions ◽  
Polymerase Chain Reactions ◽  
Type D ◽  
Multiplex Reaction ◽  
Polymerase Chain

Two multiplex polymerase chain reactions were developed for the detection of enterotoxigenic strains of Staphylococcus aureus: one multiplex reaction for the simultaneous detection of enterotoxigenic strains type A (entA), type B (entB), and type E (entE) and another for the simultaneous detection of enterotoxigenic strains type C (entC) and type D (entD). Both reactions were standardized with the use of the reference enterotoxigenic strains of S. aureus: FRI 722, producer of staphylococcal enterotoxin (SE) type A (SEA); FRI 1007, producer of SEB; FRI 137, producer of SEC1; FRI 472, producer of SED; and FRI 326, producer of SEE. Optimized methods were used to determine the presence of enterotoxigenic types for 51 S. aureus strains isolated from meat (sausage, ham, and chorizo) and dairy (powdered milk and cheese) products by the Baird-Parker technique. The enterotoxigenic capacities of the strains were determined by the indirect enzyme-linked immunosorbent assay (ELISA) with the use of reference staphylococcal toxins and antitoxins. Fifty of the 51 strains isolated were enterotoxigenic and produced one to four enterotoxin types, with the most frequently produced types being SEA and SED. Levels of correlation between the presence of genes that code for the production of SE (as determined by polymerase chain reaction) and the expression of these genes (as determined by the indirect ELISA) were 100% for SEA and SEE, 86% for SEC, 89% for SED, and 47% for SEB.

scholarly journals Suitability of Real-Time Quantitative Polymerase Chain Reaction and Enzyme-Linked Immunosorbent Assay for cry9C Detection in Mexican Corn Tortillas: Fate of DNA and Protein After Alkaline Cooking

2004 ◽  
Vol 87 (3) ◽  
pp. 639-646 ◽  
Author(s):  
Maricarmen Quirasco ◽  
Bernd Schoel ◽  
Javier Plasencia ◽  
John Fagan ◽  
Amanda Galvez
Keyword(s):  
Real Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Enzyme Linked Immunosorbent Assay ◽  
Transgenic Corn ◽  
Chain Reactions ◽  
Snack Foods ◽  
Polymerase Chain Reactions ◽  
Corn Products ◽  
Polymerase Chain ◽  
Corn Kernels

Abstract Alkaline-cooked corn, called nixtamal, is the basis for many traditional corn products such as tortillas, chips, and taco shells that are used widely in Mexico and Central America and in the preparation of snack foods that are consumed globally. To assess the effects of alkaline and thermal treatments on the detectability of DNA and protein for the presence of genetically modified sequences, various nixtamalized products were prepared from blends of conventional white corn containing 0.1, 1.0, and 10% transgenic corn (event CBH 351, StarLink™). Real-time quantitative polymerase chain reactions (RTQ–PCR) and immunoassays were used to determine the cry9C gene and protein, respectively, in unprocessed corn kernels, freshly prepared alkaline-cooked and ground corn (masa), masa flour, tortillas prepared from masa by heat treatment, chips prepared from damp masa dough by deep frying, and from tortillas processed at high (200°C) and low temperatures (70°C). In spite of progressive degradation of genomic DNA during processing, RTQ–PCR genetic analysis allowed detection and quantification of the cry9C gene in all products prepared from 10, 1, and 0.1% StarLink corn, except deep-fried chips containing 0.1% StarLink. Enzyme-linked immunosorbent assays readily detected <1ppm cry9C protein in all blends of unprocessed corn (10, 1, and 0.1% StarLink) as well as in nonfried tortilla and masa products. This technique was not suitable for thermally treated nixtamalized products containing <1% transgenic corn.

scholarly journals Simultaneous detection of the seven main tomato-infecting RNA viruses by two multiplex reverse transcription polymerase chain reactions

2012 ◽  
Vol 186 (1-2) ◽  
pp. 152-156 ◽  
Author(s):  
Stefano Panno ◽  
Salvatore Davino ◽  
Luis Rubio ◽  
Ezequiel Rangel ◽  
Mario Davino ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Rna Viruses ◽  
Simultaneous Detection ◽  
Chain Reactions ◽  
Polymerase Chain Reactions ◽  
Polymerase Chain

scholarly journals Investigation of Lethal Concurrent Outbreak of Chlamydiosis and Pigeon Circovirus in a Zoo

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1654
Author(s):  
Wei-Tao Chen ◽  
Chin-Ann Teng ◽  
Cheng-Hsin Shih ◽  
Wei-Hsiang Huang ◽  
Yi-Fan Jiang ◽  
...  
Keyword(s):  
Disease Outbreaks ◽  
Chlamydia Psittaci ◽  
Bursa Of Fabricius ◽  
Chain Reactions ◽  
Renal Epithelium ◽  
Polymerase Chain Reactions ◽  
Transmission Electron ◽  
Intracytoplasmic Inclusion Bodies ◽  
Polymerase Chain ◽  
Streptopelia Orientalis

During the spring, an outbreak of sudden death involving 58 birds occurred in a zoo. Histopathological examinations revealed variable numbers of intracytoplasmic basophilic microorganisms in the macrophages, hepatocytes, and renal epithelium of most birds, along with occasional botryoid intracytoplasmic inclusion bodies within histiocytes in the bursa of Fabricius. Based on the results of histopathological examinations, immunohistochemical staining, transmission electron microscopy, and polymerase chain reactions, genotype B Chlamydia psittaci infection concurrent with pigeon circovirus (PiCV) was diagnosed. A retrospective survey, including two years before the outbreak and the outbreak year, of C. psittaci and PiCV infections of dead birds in the aviaries, revealed that the outbreak was an independent episode. The findings of this study indicate that concurrent infection with C. psittaci and PiCV might lead to lethal outbreaks of chlamydiosis, particularly Streptopelia orientalis. In addition, persistently monitoring both pathogens and identifying potential PiCV carriers or transmitters might also help prevent lethal disease outbreaks.

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