Table 1.
LAMP primers for detection of N. meningitidis.
Fig 1.
Location of the Nm LAMP primer in the capsular transport gene ctrA (1176 bp).
Fig 2.
Real-time monitoring of Nm LAMP reaction mixture turbidity.
N. meningitidis serogroup B reference DNA; dilution series from 1,000,000 copies to 1 copy. The molecular weight of the genomic DNA is 2.2 Mbp. The molecular weight of one copy is 2.5 fg. The LAMP assay detected 10 copies of N. meningitidis serogroup B within 60 min.
Fig 3.
Electrophoretic analysis of Nm LAMP products.
The Nm LAMP products showed a ladder-like pattern on 2% gel electrophoresis and ethidium bromide staining. Lane M, molecular size marker (100-bp ladder; New England Biolabs, Beverly, MA); lanes 1–3, 9, 10, and 12–14: clinical samples (negative for N. meningitidis); lanes 4–8 and 11: clinical samples (positive for N. meningitidis); lane 15: negative control; lane 16: positive control
Table 2.
Nonspecific LAMP reaction test using ctrA primer sets.
Table 3.
Detection limits of Nm LAMP and PCR assays targeting the ctrA gene and using Nm-serogroup-B-spiked CSF specimens.
Fig 4.
Visual-inspection of dye-mediated monitoring of the Nm LAMP assay.
(A) The original pale-yellow color of the visual inspection dye (Kaneka, Co., Ltd, Osaka, Japan) changed to blue in the case of a positive reaction; in the case of a negative reaction, the original pale-yellow color was retained. (B) Visual observation after 7 days.
Table 4.
Comparison of diagnostic methods for clinical specimens.
Table 5.
A comparative analysis of PCR and Nm LAMP detection of N. meningitidis.