Loop-mediated isothermal amplification for the rapid, sensitive, and specific detection of the O9 group of Salmonella in chickens.
In the present study, the loop-mediated isothermal amplification (LAMP) assay was developed to amplify the fragments of the O9 Salmonella-specific insertion element and evaluated in the laboratory for its potential use in a field situation, such as poultry farms. Among the bacteria tested, a positive reaction was observed only for 128 strains of 6 serovars of the O9 group Salmonella, such as Enteritidis (SE) and Pullorum. The detection limit of the LAMP assay was 10(3)CFU/ml, which was more sensitive than that of the polymerase chain reaction (PCR) assay with the same target gene (10(6)CFU/ml). The final results were obtained within 30 min for the LAMP assay, while the PCR assay needed a total of 120 min. When the LAMP assay was applied to the enrichment broth mixed with cecal dropping samples either spiked with SE in vitro or excreted by SE-inoculated hens, the results were comparable to those of the conventional plating method including 2 separate enrichments. In conclusion, the LAMP assay developed in the present study is an effective method for the specific detection of the O9 group Salmonella serovars, including SE.
Laboratory of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.
Masashi
M
Okamura
Yousuke
Y
Ohba
Shuichi
S
Kikuchi
Akiko
A
Suzuki
Hajime
H
Tachizaki
Kazuaki
K
Takehara
Masanari
M
Ikedo
Tadashi
T
Kojima
Masayuki
M
Nakamura
D000818:Animals; D001431:Bacteriological Techniques / Q000662:veterinary; D002645:Chickens; D005243:Feces / Q000382:microbiology; D021141:Nucleic Acid Amplification Techniques; D011201:Poultry Diseases / Q000175:diagnosis* / Q000382:microbiology; D012475:Salmonella / Q000145:classification* / Q000302:isolation & purification*; D012481:Salmonella Infections, Animal / Q000175:diagnosis* / Q000382:microbiology; D012680:Sensitivity and Specificity