Evaluation of 2 Commercial Assays for the Detection of Lymphogranuloma Venereum in Rectal Samples.

BACKGROUND: The early identification of the Chlamydia trachomatis variants that cause lymphogranuloma venereum (LGV) is very important to establish an adequate antibiotic treatment. This identification should be made with molecular techniques that are easy to perform and accessible to most microbiology laboratories. The objective of this study was to evaluate 2 real-time polymerase chain reaction (PCR)-based assay (VIASURE Haemophilus ducreyi + C. trachomatis (LGV) real-time PCR detection kit and the Allplex Genital ulcer Assay) for the detection of LGV in rectal samples. MATERIALS AND METHODS: Prospective study on positive rectal samples for C. trachomatis. All samples were processed in parallel by both tests. As a molecular reference method and to solve possible discrepancies between both assays, a PCR-based restriction fragment length polymorphism analysis of the major outer membrane protein gene (omp1) was used. RESULTS: In total, we detected 157 positive rectal samples for C. trachomatis, of which 36 were identified as LGV by PCR-based restriction fragment length polymorphism analysis. The positive percent agreement, negative percent agreement, and overall percent agreement were 88.9%, 100%, and 97.3%, respectively, for the Allplex Genital ulcer assay and 91.6%, 100%, and 97.1%, respectively, for the VIASURE assay. In the direct comparison between the Seegene assay and the VIASURE assay, we obtained a kappa concordance index of 0.98 between both tests. CONCLUSIONS: According to the results obtained, both tests could be used for the detection of LGV in rectal samples.

[Evaluation of the cobas 4800 CT/NG test for detecting Chlamydia trachomatis]. / Evaluación del cobas 4800 CT/NG test para la detección de Chlamydia trachomatis.

INTRODUCTION: To evaluate the new automated system cobas 4800 CT/NG test for detection of Chlamydia trachomatis in urogenital specimens. MATERIAL AND METHODS: We analyzed 696 specimens (488 swabs from urethral or cervical specimens, and 208 urines) to detect C. trachomatis. The results of the cobas 4800 CT/NG test (c4800) were compared to those obtained with Cobas AMPLICOR CT/NG test (CAM). Discordant results were analyzed with a conventional PCR assay and microchip electrophoresis system in agarose gel, MultiNA. RESULTS: We made two simultaneous analyses. In the first one, we compared the results obtained with swab specimens using the c4800 system and CAM. In this case, the sensitivity, the specificity, the positive and negative predictive values (PPV and NPV) were: 77.9%, 100%, 100% and 96% respectively. In the second one, we compared the results obtained for urine and its corresponding swab specimens on the c4800. The values obtained were: 100%, 98.9%, 92.9% and 100% respectively. The kappa values of these comparisons were: 0.857 for swab specimens on the c4800 and CAM, and 0.957 for urine versus swab specimens on the c4800. CONCLUSIONS: The results obtained with c4800 system were completely comparable with those obtained with CAM. We also noted an excellent correlation with these results when we compared swab specimens with their urine samples in the c4800 system. Therefore this sample type could be used routinely to diagnose infections in men and women.

Evaluation of the cobas 4800 CT/NG Test for detecting Chlamydia trachomatis and Neisseria gonorrhoeae DNA in urogenital swabs and urine specimens.

We have evaluated 696 samples (488 swabs and 208 urine specimens) with the cobas 4800 (c4800) CT/NG Test for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae DNA in swab and urine specimens. c4800 results were compared with those obtained from COBAS AMPLICOR (CAM) CT/NG Test. Discordant results were reanalyzed with the MultiNA system and compared with clinical data. For C. trachomatis detection by both methods, we obtained 93.8%, 100%, 100%, and 99.1% for sensitivity, specificity, and positive and negative predictive values, respectively. For urine specimens analyzed in c4800, our results were 96.6%, 100%, 100%, and 99.4%, respectively. For N. gonorrhoeae detection, swab results were:88.0%, 100%, 100%, and 99.4%. For urine specimen, results obtained were 100%, 100%, 100%, and 100%. Reanalyses were all concordant between both methods. c4800 results were comparable with those obtained with the CAM system. We had an excellent correlation between swab and urine specimens analyzed by c4800.