Objectives Nucleic acid amplification testing (NAAT) has become the preferred method to detect Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) infections. Anyway, no commercial test has been cleared so far for use with extra-genital swab samples.
In this study Versant CT/GC DNA 1.0 (Siemens) performances have been evaluated by testing ocular, rectal or pharyngeal secretions collected by Siemens collection devices.
Methods Study group. A prospective study was performed with 7 newborns with conjunctivitis, and 183 subjects attending the STD Outpatients Clinic of St. Orsola Hospital, Bologna. The latter ones were enrolled because having unsafe receptive anal and/or pharyngeal sex intercourses.
NAAT methods. All the specimens were tested by Versant CT/GC DNA 1.0.
In case of a Versant CT positive result, we collected the corresponding remnant DNA extract and used it as a template for omp1 semi-nested-PCR. RFLP analysis of PCR-positive samples was carried out by using AluI, HinfI and DdeI as restriction enzymes, for genotyping.
All the specimens scored GC positive were retested by a “home-made” PCR assay, targeting cppB gene.
Results A total of 253 samples were obtained. In particular, we tested 14 conjunctival swabs, 155 pharyngeal swabs and 84 rectal swabs.
Versant assay scored as GC positive 13 pharyngeal and 7 rectal samples. All these specimens were confirmed reactive by cppB PCR. Regarding CT infections, Versant assay identified 2 ocular specimens as positive: one was further genotyped as E and the other one as F. Moreover, we found 4 positive pharyngeal specimens (genotypes E, F, J) and 12 rectal samples (genotypes E, H, J, L2).
Conclusions Versant CT/GC DNA 1.0 demonstrated to be a very good method to identify extra-genital infections due to chlamydia and/or gonorrhoea. Because of its performances, and the walk-away capability of the system, this assay can be considered an excellent choice for CT/GC diagnosis.
- Chlamydia conjuntivitis in newborns
- real time PCR