3.4. The application of the immunochromatographic strip test for
the detection of S. typhi in human serum
To evaluate our method, the immunochromatographic strip
test was utilized to detect S. typhi in human serum. Different
concentrations of S. typhi between 1.14
×
105 cfu mL−1 and
1.14
×
108 cfu mL−1 were spiked to normal human serum. The
results showed that two red dots appeared on all nitrocellulose
membranes (data not shown). The sensitivity of the strip test was
evident from the detection of 20 positive human serums (spiked
normal human serum) and 20 negative human serums (normal
human serum) (see supporting information Table S1). Among 20
positive human serums samples, 20 samples (100%) were positively
detected, while 20 of 20 negative human serums were confirmed to
be negative by the strip test. Therefore, the strip test was effective
for the detection of S. typhi in serum samples.