TABLE 2

Results of method validation using 35 well-characterized N. gonorrhoeae isolatese

TargetSequence type result(s) for the 35 control isolates (no. of isolates with result) determined by:Tm (°C)Mean ΔTm ± SD (°C)Sensitivityc (%) (95% CI)Specificityc (%) (95% CI)
DNA sequencingReal-time PCR/HRM analysisRangeMean ± SD
opaPositive (35)Positive (35)76.63–77.2276.98 ± 0.13NA100 (90–100)NAd
Negative (0)Negative (0)NANA
porAPositive (35)Positive (35)73.79–74.8874.36 ± 0.20NA100 (90–100)NAd
Negative (0)Negative (0)NANA
penA Gly545SerNonmosaic (23)Nonmosaic (23)NAaNAa100 (66–100)100 (87–100)
Nonmosaic Gly545 (GGC) (3)Nonmosaic Gly545 (GGC) (3)85.05–85.23a85.14 ± 0.08a0.46 ± 0.05
Mosaic Gly545Ser (AGC) (9)Mosaic Gly545Ser (AGC) (9)84.09–84.7284.47 ± 0.20
penA Ala501Nonmosaic (26)Nonmosaic (26)NAbNAb100 (66–100)100 (87–100)
Mosaic (9)Mosaic (9)83.59–84.3584.17 ± 0.19NI
gyrA Ser91PheGyrA Ser91 (TCC), Ala92 (GCA) (11)GyrA Ser91 (TCC), Ala92 (GCA) (11)77.97–78.1678.08 ± 0.05100 (86–100)100 (72–100)
GyrA Ser91Phe (TTC), Ala92 (GCA) (23)GyrA Ser91Phe (TTC), Ala92 (GCA) (23)77.29–77.5977.47 ± 0.070.61 ± 0.06
GyrA Ser91Phe (TTC), Ala92Ser (TCA) (1)GyrA Ser91Phe (TCC), Ala92Ser (TCA) (1)76.15–76.1776.16 ± 0.021.25 ± 0.01
23S rRNA A2059GA2059 (34)A2059 (34)81.33–81.5281.44 ± 0.030.22 ± 0.02100 (3–100)100 (90–100)
A2059G (1)A2059G (1)81.61–81.7081.67 ± 0.03
23S rRNA C2611TC2611 (34)C2611 (34)75.69–76.3376.12 ± 0.160.75 ± 0.05100 (3–100)100 (90–100)
C2611T (1)C2611T (1)75.08–75.5575.30 ± 0.20
rpsE Thr24ProThr24 (ACC) (34)Thr24 (ACC) (34)73.87–74.3474.08 ± 0.070.68 ± 0.01100 (3–100)100 (90–100)
Thr24Pro (CCC) (1)Thr24Pro (CCC) (1)74.66–74.9474.76 ± 0.09
16S rRNA C1192TC1192 (34)C1192 (34)81.38–81.7281.56 ± 0.080.69 ± 0.01100 (3–100)100 (90–100)
C1192T (1)C1192T (1)80.74–80.9480.82 ± 0.09
  • a Only nonmosaic pattern XIX (with penA Gly545) showed cross-amplification.

  • b No amplification was observed for all other nonmosaic penA patterns tested.

  • c Sensitivity is the probability that an isolate was correctly identified as being positive by HRM analysis for the target sequence (species identification, mosaic, or mutation); specificity is the probability that an isolate was correctly identified as being negative by HRM analysis for the target sequence (species identification, mosaic, or mutation).

  • d Specificity was 100% considering that all 19 nongonococcal control strains were correctly characterized as non-N. gonorrhoeae isolates (see Table S1 in the supplemental material).

  • e NA, not applicable; NI, not interpretable.