A profile of the cobas® CT/NG assay on the cobas® 6800/8800 system for detection of Chlamydia trachomatis and Neisseria gonorrhoeae

Microbial interactions among Gardnerella, Prevotella and Fannyhessea prior to incident bacterial vaginosis: protocol for a prospective, observational study

INTRODUCTION

The aetiology of bacterial vaginosis (BV), a biofilm-associated vaginal infection, remains unknown. Epidemiologic data suggest that it is sexually transmitted. BV is characterised by loss of lactic acid-producing lactobacilli and an increase in facultative and strict anaerobic bacteria. Gardnerella spp are present in 95%-100% of cases; Gardnerella vaginalis has been found to be more virulent than other BV-associated bacteria (BVAB) in vitro. However, G. vaginalis is found in women with normal vaginal microbiota and colonisation is not sufficient for BV development. We hypothesise that Gardnerella spp initiate BV biofilm formation, but incident BV (iBV) requires incorporation of other key BVAB (ie, Prevotella bivia, Fannyhessea vaginae) into the biofilm that alter the transcriptome of the polymicrobial consortium. This study will investigate the sequence of microbiologic events preceding iBV.

METHODS AND ANALYSIS

This study will enrol 150 women aged 18-45 years with normal vaginal microbiota and no sexually transmitted infections at a sexual health research clinic in Birmingham, Alabama. Women will self-collect twice daily vaginal specimens up to 60 days. A combination of 16S rRNA gene sequencing, qPCR for Gardnerella spp, P. bivia and F. vaginae, and broad range 16S rRNA gene qPCR will be performed on twice daily vaginal specimens from women with iBV (Nugent score 7-10 on at least 2 consecutive days) and controls (with comparable age, race, contraceptive method and menstrual cycle days) maintaining normal vaginal microbiota to investigate changes in the vaginal microbiota over time for women with iBV. Participants will complete daily diaries on multiple factors including sexual activity.

ETHICS AND DISSEMINATION

This protocol is approved by the University of Alabama at Birmingham Institutional Review Board (IRB-300004547) and written informed consent will be obtained from all participants. Findings will be presented at scientific conferences and published in peer-reviewed journals as well as disseminated to providers and patients in communities of interest.

A retrospective evaluation of the Euroarray STI-11 multiplex system for the detection of eight STI causing agents

With an incidence of more than > 1,000,000/day, sexually transmitted diseases remain a major challenge for health care systems worldwide. To reduce disease burden, complications, and spread, rapid diagnosis permitting early therapy is pivotal. The range of pathogens is wide and co-infections are common. This complicates pre-analytics, which are based on different laboratory techniques with potentially long turnaround times, e.g., cultivation and multistep serologies. Multiplex PCR provides the opportunity to overcome these limitations. In this study, we evaluated a novel assay, the Euroarray STI-11 microarray (EA; Euroimmun Medizinische Labordiagnostika), for the detection of eight obligate or facultative pathogens. Three-hundred-thirteen clinical specimens, which had been tested and pre-characterized for STI causing agents as part of routine diagnostics, were used as cases and controls in this retrospective study. The EA detected 34/44 Chlamydia trachomatis, 48/50 HSV-1, 50/50 HSV-2, 48/48 Mycoplasma hominis, 45/47 Neisseria gonorrhoeae, 9/11 Treponema pallidum, 46/46 Ureaplasma parvum, and 49/49 Ureaplasma urealyticum infections, respectively. 293 samples were EA positive, with polymicrobial infections (positive for two to six microbial or viral agents) detected in 130/293 cases. Specificities were 100% in the respective control groups (n = 18-48 depending on targeted pathogen) except for N. gonorrhoeae (25/26) and U. urealyticum (44/45). The broad spectrum of obligate and facultative pathogens targeted by the EA makes it a valuable tool in the setting of STI diagnostics and surveillance. The test has the potential to diagnose diseases neglected or overlooked in routine clinical practice. Besides a low sensitivity for C. trachomatis, the EA demonstrated high performance for all analyzed parameters. Further studies are warranted in order to capture a larger variety of the tested pathogens.

Clinical performance of four multiplex real-time PCR kits detecting urogenital and sexually transmitted pathogens

OBJECTIVES

We evaluated the clinical performances of four multiplex real-time PCR commercial kits for the detection of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis: the STI PLUS ELITe MGB kit (ELITechGroup), N. gonorrhoeae/C. trachomatis/M. genitalium/T.vaginalis Real-TM kit (Sacace Biotechnologies), Allplex STI Essential kit (Seegene), and FTD Urethritis Plus kit (Fast-Track Diagnostics).

METHODS

The kit performance for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis detection was compared to that of the cobas CT/NG and TV/MG kits (Roche Diagnostics) using 425 samples, mainly urine and cervicovaginal, throat and rectal swabs. Detection of Ureaplasma parvum, U. urealyticum and Mycoplasma hominis were compared to that of in-house TaqMan PCRs.

RESULTS

The four kits showed good performances for the detection of C. trachomatis. They all presented a low positive agreement for the detection of M. genitalium and T. vaginalis (ranges 63.3-74.1% and 51.2-68.4%, respectively) compared to the cobas MG/TV kit. The Seegene and Sacace kits showed additional low positive agreement for the detection of N. gonorrhoeae (71.2%, 95%CI 61.8-79.0 and 63.1%, 95%CI 53.5-71.8, respectively). We observed a slight but significant lower negative agreement for N. gonorrhoeae detection using the ELITechGroup kit (92.5%, 89.1-94.9) and for M. genitalium detection using the Fast-Track kit (93.2%, 89.6-95.7) compared to other kits.

CONCLUSION

Multiplex real-time PCR kits are convenient methods for the detection of several pathogens associated with sexually transmitted infections (STIs) in a single step, but colonizing Ureaplasma spp. and M. hominis species should not be included in these kits. Users should be aware of the weak performance of some kits for the detection of M. genitalium and T. vaginalis.