TABLE 3.
Comparison of results of mPCR/RLB and comparator methods in detection of genital infection/colonization with 14 recognized or putative genital pathogens
| Organism | Limit of detectiona (ng/μl) | No. positively detected by mPCR/RLBb | Comparator methodc (target) | No. positively detected by comparator method |
|---|---|---|---|---|
| T. vaginalis | 1.5 × 10−9 | 1 | sPCR (18S rRNA gene) | 1 |
| S. pneumoniae | 7.4 × 10−1 | 1 | Culture | 1 |
| N. gonorrhoeae | 4.3 × 10−2 | 7 | Culture and Amplicor PCR | 2 (+5)d |
| C. trachomatis | 7.0 × 10−11 | 55 | Amplicor PCR | 50 (+5)d |
| Ureaplasma spp.e | 7.8 × 10−9 | 84 | Culture | 86 |
| G. vaginalis | 7.8 × 10−3 | 3 | sPCR (16-23S rRNA gene) | 3 |
| H. influenzae | 7.0 × 10−8 | 31 | Culture | 35 |
| HSV1 | 4.3 × 10−8 | 8 | sPCR (pol) | 5 |
| N. meningitides | 8.2 × 10−8 | 2 | Culture | 1 |
| M. hominis | 5.5 × 10−1 | 15 | Culture | 16 |
| M. genitalium | 2.1 × 10−9 | 15 | sPCR (16S rRNA gene) | 15 |
| Adenovirus | 6.3 × 10−7 | 4 | sPCR (hexon gene) | 4 |
For mPCR/RLB.
sPCR, using the same primers as those for mPCR, was performed on specimens with discrepant mPCR/RLB and culture results. In all cases the mPCR/RLB and sPCR results were concordant.
Comparator methods were either the culture of urethral swab collected at the same time as first-voided urine specimen or sPCR on the same urine DNA extract as that used for mPCR/RLB, using a different, species-specific target (except for adenoviruses, for which the same hexon gene target was used).
Of the 7 and 55 specimens positive by mPCR/RLB for N. gonorrhoeae and C. trachomatis, respectively, only 2 and 50 were positive initially in the Roche Amplicor PCR; all were positive on retesting.
Urethral specimens were cultured for ureaplasmas, but isolates were not speciated. Ureaplasma spp. identified in the mPCR/RLB-positive specimens are shown in Fig. 2.