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.
Okamura
Masashi
M
Laboratory of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.
Ohba
Yousuke
Y
Kikuchi
Shuichi
S
Suzuki
Akiko
A
Tachizaki
Hajime
H
Takehara
Kazuaki
K
Ikedo
Masanari
M
Kojima
Tadashi
T
Nakamura
Masayuki
M
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