Simple and rapid detection of Salmonella serovar Enteritidis under field conditions by loop-mediated isothermal amplification.
OBJECTIVE
The objective of this study is to develop a serovar-specific loop-mediated isothermal amplification (LAMP) method for sensitive, rapid, and inexpensive detection of Salmonella serovar Enteritidis under field conditions.


METHODS
A set of six specific primers was designed with Salmonella Enteritidis DNA as the target. LAMP conditions were optimized by incubating the target DNA with the Bst DNA polymerase large fragment in a simple water bath. The sensitivity and specificity of LAMP was then compared with those of fluorescent quantitative real-time polymerase chain reaction (FQ-PCR).


RESULTS
The results were as follows. (1) Serovar-specific Salmonella Enteritidis DNA was amplified at 65°C in as early as 20min in a water bath. (2) A colour change visible to the naked eye indicated a positive amplification reaction. (3) The detection limit of the LAMP assay was 4 copies μl(-1) ; thus, the sensitivity and specificity of this assay is similar to those of the FQ-PCR.


CONCLUSIONS
LAMP is a high-throughput detection technique with high sensitivity, specificity, and simplicity; these factors make it suitable for specifically detecting Salmonella Enteritidis under field conditions and in laboratory settings. Thus, LAMP eliminates the need for complicated equipment and technical training in the detection of this specific serovar.


CONCLUSIONS
This is the first study involving the use of LAMP to detect Salmonella serovar-specific DNA sequences. It is also the first to report an ideal method of distinguishing between Salmonella Enteritidis and other Salmonella under field conditions.
Yang
J-L
JL
Chongqing Academy of Animal Science, Chongqing, China.
Ma
G-P
GP
Yang
R
R
Yang
S-Q
SQ
Fu
L-Z
LZ
Cheng
A-C
AC
Wang
M-S
MS
Zhang
S-H
SH
Shen
K-F
KF
Jia
R-Y
RY
Deng
S-X
SX
Xu
Z-Y
ZY
D005516:Food Microbiology / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques; D012477:Salmonella enteritidis / Q000235:genetics / Q000502:physiology*; D012680:Sensitivity and Specificity; D013997:Time Factors