TABLE 3

Performance of the real-time PCR platform in characterizing the collection of 193 N. gonorrhoeae isolates alone and combined with the 39 N. gonorrhoeae control strainsg

Phenotypic targetTarget sequence(s)N. gonorrhoeae isolates collected during 1989–2014 (n = 193)All N. gonorrhoeae strains (n = 232), including 39 controls
Test resultNo. of isolatesaNo. of isolates with AST resultbSensitivityd (%) (95% CI)Specificityd (%) (95% CI)Test resultNo. of strainsa,eNo. of isolates with AST resultbSensitivityd (%) (95% CI)Specificityd (%) (95% CI)
SRSR
Species identificationopa and/or porAPositive193NANA100 (97–100)NAPositivee232NANA100 (98–100)e100 (82–100)e
NegativeNegativee19
CROpenA Gly545Ser and/or penA Ala501Positive1616NA92 (87–95)Positive26242100 (16–100)90 (85–93)
Negative177177Negative206206
CFXpenA Gly545Ser and/or penA Ala501Positive1697100 (47–100)95 (91–98)Positive26141292 (64–100)94 (90–96)
Negative177177Negative2062051f
AZMc23S rRNA A2059G or 23S rRNA C2611TPositiveNA100 (97–100)Positive44100 (40–100)100 (98–100)
Negative193193Negative228228
CIPgyrA Ser91PhePositive5858100 (91–100)100 (96–100)Positive8383100 (96–100)100 (98–100)
Negative135135Negative149149
SPCrpsE Thr24Pro or 16S rRNA C1192TPositiveNA100 (97–100)Positive33100 (29–100)100 (98–100)
Negative193193Negative229229
  • a Numbers are based on the results of the multiplex real-time PCR platform.

  • b AST was categorized based on EUCAST criteria with the exception of AZM (see below).

  • c AZM resistance was defined as an MIC of >2 μg/ml.

  • d Sensitivity was the probability that an isolate categorized as being resistant was identified as positive by real-time PCR; specificity was the probability that an isolate categorized as being sensitive was identified as negative by real-time PCR.

  • e For the evaluation of “species identification,” we also included the 19 nongonococcal Neisseria species strains.

  • f Strain WHO L (nonmosaic penA gene with an additional mutation encoding the Ala501Val amino acid substitution).

  • g AST, antimicrobial susceptibility testing by Etest; R, resistant; S, susceptible; CI, confidence interval; —, zero; NA, not applicable.