Detection of Live Salmonella sp Cells in Produce by a TaqMan-Based Quantitative Reverse Transcriptase Real-Time PCR Targeting invA mRNA

被引:100
作者
Gonzalez-Escalona, Narjol [1 ]
Hammack, Thomas S. [1 ]
Russell, Mindi [1 ]
Jacobson, Andrew P. [1 ]
De Jesus, Antonio J. [1 ]
Brown, Eric W. [1 ]
Lampel, Keith A. [1 ]
机构
[1] FDA, Ctr Food Safety & Appl Nutr, College Pk, MD 20740 USA
关键词
POLYMERASE-CHAIN-REACTION; MAMMALIAN-CELLS; VIBRIO-CHOLERAE; RT-PCR; AMPLIFICATION; QUANTIFICATION; GENE; TYPHIMURIUM; SEQUENCE; FOOD;
D O I
10.1128/AEM.02686-08
中图分类号
Q81 [生物工程学(生物技术)]; Q93 [微生物学];
学科分类号
071005 ; 0836 ; 090102 ; 100705 ;
摘要
Salmonella enterica contamination in foods is a significant concern for public health. When DNA detection methods are used for analysis of foods, one of the major concerns is false-positive results from the detection of dead cells. To circumvent this crucial issue, a TaqMan quantitative real-time RT-PCR (qRT-PCR) assay with an RNA internal control was developed. invA RNA standards were used to determine the detection limit of this assay as well as to determine invA mRNA levels in mid-exponential-, late-exponential-, and stationary-phase cells. This assay has a detection limit of 40 copies of invA mRNA per reaction. The levels of invA mRNA in mid-exponential-, late-exponential-, and stationary-phase S. enterica cells was approximately 1 copy per 3 CFU, 1 copy per CFU, and 4 copies per 10(3) CFU, respectively. Spinach, tomatoes, jalapeno peppers, and serrano peppers were artificially contaminated with four different Salmonella serovars at levels of 10(5) and less than 10 CFU. These foods were analyzed with qRT-PCR and with the FDA's Bacteriological Analytical Manual Salmonella culture method (W. A. Andrews and T. S. Hammack, in G. J. Jackson et al., ed., Bacteriological analytical manual online, http://www.cfsan.fda.gov/similar to ebam/bam-5.html, 2007). Comparable results were obtained by both methods. Only live Salmonella cells could be detected by this qRT-PCR assay, thus avoiding the dangers of false-positive results from nonviable cells. False negatives (inhibition of the PCR) were also ruled out through the use of an RNA internal control. This assay allows for the fast and accurate detection of viable Salmonella spp. in spinach, tomatoes, and in both jalapeno and serrano peppers.
引用
收藏
页码:3714 / 3720
页数:7
相关论文
共 41 条
[1]   Emerging foodborne diseases [J].
Altekruse, SF ;
Cohen, ML ;
Swerdlow, DL .
EMERGING INFECTIOUS DISEASES, 1997, 3 (03) :285-293
[2]  
Andrews W., 2007, Salmonella. Bacteriological analytical manual
[3]  
Andrews W.H., 2003, BACTERIOLOGICAL ANAL, V8th
[4]  
BLACKSTONE GM, 2005, 105 GEN M AM SOC MIC
[5]  
BOHAYCHUK VM, 2007, J FOOD PROTECT, V70, P1080
[6]   Comparative genetics of the inv-spa invasion gene complex of Salmonella enterica [J].
Boyd, EF ;
Li, J ;
Ochman, H ;
Selander, RK .
JOURNAL OF BACTERIOLOGY, 1997, 179 (06) :1985-1991
[7]  
Crump JA, 2004, B WORLD HEALTH ORGAN, V82, P346
[8]  
Drahovská H, 2001, BIOLOGIA, V56, P611
[9]   Comparison of cultivation and PCR-hybridization for detection of Salmonella in porcine fecal and water samples [J].
Feder, I ;
Nietfeld, JC ;
Galland, J ;
Yeary, T ;
Sargeant, JM ;
Oberst, R ;
Tamplin, ML .
JOURNAL OF CLINICAL MICROBIOLOGY, 2001, 39 (07) :2477-2484
[10]   Establishment of a real-time PCR-based approach for accurate quantification of bacterial RNA targets in water, using Salmonella as a model organism [J].
Fey, A ;
Eichler, S ;
Flavier, S ;
Christen, R ;
Höfle, MG ;
Guzmán, CA .
APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 2004, 70 (06) :3618-3623