GC Nucleic Acid Amplification Tests Research Articles

P228 Evaluating the use of extra-genital Chlamydia trachomatis (CT) and Neisseria gonorrhoea (GC) nucleic acid amplification tests (NAATs) in non-MSM populations

Background/introduction Our clinic performs routine oral and anal CT and GC NAATs following disclosure during sexual history of oral or receptive anal sex. Specimens are analysed using the Abbott M2000 assay, costing £4.50 per dual NAAT. Aim(s)/objectives We report the findings of this practice, focusing on clinical and partner notification outcomes, and the cost per diagnosis. Methods We included all non-MSM patients with isolated extra-genital CT or GC infection from 1/8/14 to 31/7/15. We excluded contacts of either infection, plus those without GC confirmed by culture or second NAAT platform. Retrospective case note review was performed for identified cases. Results In total 8796 NAATs were processed in non-MSM patients, of which 3813 (43%) were extra-genital. In heterosexual men we identified 3 pharyngeal GC cases and one contact, and one pharyngeal CT case with one contact. In women there were 2 pharyngeal GC cases, one pharyngeal CT case and one rectal CT case with no additional contacts. The spend per pharyngeal diagnosis was £1519 in males and £3138 in women. The spend per rectal diagnosis in women was £1665. Discussion/conclusion Our screening practice has picked up only a small number of cases which would otherwise have been missed. 25% (2/8) of those cases had verified contacts identified. The cost implication of such screening is high, meaning that ongoing routine screening is not viable. In our relatively low-prevalence setting we now intend to target our screening in line with BASHH CEG guidance which will provide significant cost savings.

P3 An audit of pharyngealneisseria gonorrhoeaetreatment and test of cure practices

Background Pharyngeal Neisseria gonorrhoeae infections are usually asymptomatic and often diagnosed using nucleic acid amplification tests (NAATs). This reservoir of bacteria may contribute to antibiotic resistance through recombination with pharyngeal commensal bacteria. Therefore adherence to treatment guidelines is imperative and guidelines recommend a test of cure (TOC) after treatment. Objective To evaluate adherence to local guidelines of treating Neisseria gonorrhoeae pharyngeal infection and TOC results. Methods Retrospective case note review of all male positive pharyngeal GC NAAT tests at a sexual health clinic in 2013. The treatment and TOC details were evaluated. Results Of 133 positive NAATs, 125/133 received treatment at our clinic. 83%(104/125) received first line treatment and 74%(93/125) returned for a TOC. The mean return time for negative TOC tests was 25 ± 9 days. 3 patients remained GC NAAT positive at TOC and 2 indeterminate, at 22 ± 3 days after treatment. 4/5 received first line treatment and 1/5 received second line, due to allergy. Without further treatment, all repeat NAAT tests were negative and all five cultures did not grow Neisseria gonorrhoeae . All 5 were asymptomatic and denied sexual contact between treatment and TOC. None were co-infected with other STI’s. Discussion/conclusion There was a high return rate for TOC and high levels of adherence to the local treatment protocol. Those with positive or indeterminate TOC had no distinguishing features or treatment differences, compared with those who tested negative. The treatment to TOC times for both groups was beyond guideline recommendations. Repeat negative NAAT testing suggests no treatment failure in these cases.

P2.001 Performance of the Hologic Gen-Probe APTIMA Assays and PANTHERTM Instrumentation For the Confirmation of Neisseria Gonorrhoeae in Genital and Non-Genital Samples

Nucleic Acid Amplification Tests (NAATs) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) have become routine. These methods are validated for use with urogenital samples and have a faster turn-around-time...

P2.035 As Nucleic Acid Amplification Testing For Neisseria Gonorrhoeae Increases is Culture Confirmation Decreasing?

BackgroundWith the advent of nucleic acid amplification tests (NAATs) to detect Neisseria gonorrhoeae (GC) the use of selective culture is now reserved largely for symptomatic patients or confirmation of GC...

Confirmation of neisseria gonorrhoeae infection using the hologic gen-probe aptima assays and panther instrumentation

New generation nucleic acid amplification tests (NAATs) for <i>Chla-mydia trachomatis</i> (CT) and <i>Neisseria gonorrhoeae</i> (GC) have become routine. While these methods are validated for use with non-invasive samples, faster turn-around time with automation, none of the NAATs are 100% sensitive or specific. The 2005 Public Health Laboratory Network (PHLN) guideline recommends repeat testing of all initial positive GC NAAT results with an alternate suitable NAAT assay. In this study, results from 345 937 patient samples from five laboratories were reviewed in accordance with these recommendations. All laboratories used the APTIMA Combo 2 (AC2) and APTIMA <i>Neisseria gonorrhoeae</i> (AGC) assays with the PANTHER instrument. A total of 4721 samples had evaluable results for both assays; 94.51% (4462) of samples were positive in both assays. Of the 259 discordant samples, 111 (2.35%) AC2 positive samples were negative with the AGC assay, 30 (0.64%) AC2 positive samples were equivocal with the AGC assay; 96 (2.03%) AC2 equivocal samples were negative with the AGC assay and 22 (0.47%) AC2 equivocal samples were positive with the AGC assay. Without a confirmatory assay, false positive results would have been reported for 111 samples representing 0.03% of all samples tested. Determination of the significance of the equivocal results requires clinical intervention.

Positive nucleic acid amplification tests for Neisseria gonorrhoeae in young people tested as part of the National Chlamydia Screening Programme

Little information is available on the prevalence of Neisseria gonorrhoeae (GC) infections outside genitourinary (GU) medicine clinics. A number of National Chlamydia Screening Programme areas now carry out simultaneous testing for Chlamydia trachomatis (CT) and GC in a single sample using nucleic acid amplification tests (NAATs). The aim of this study was to gather together data on dual testing from community settings. Information was collected from five programme areas. A total of 219,412 results were recorded with 18,370 CT positives, 1226 GC positives and among these 554 were with dual CT/GC infection. These figures highlight the fact that substantial numbers of positive GC NAAT results are found outside GU settings. An assessment of both the prevalence of GC and the proportion of extra cases that can be detected in all settings is needed, together with the implementation of robust plans to confirm, treat and manage these patients.

Gonococcal NAATs: what is the current state of play in England and Wales?

The aim of this study was to determine how widespread the use is of dual nucleic acid amplification tests (NAATs) for the diagnosis of both Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) in England and Wales. A structured telephone questionnaire was used to collect information on the method of dual testing used by laboratories, the patient groups tested, the types of specimens obtained and the use of GC culture. Of the 108 laboratories participating, 29% performed dual CT and GC NAAT assays. The platforms used included: (i) BD Probetec (19/31), (ii) Aptima Combo 2 (9/31) and (iii) COBAS AMPLICOR (2/31). GC-positive specimens were either repeated using the same test (21) or an alternative target (9). Most laboratories confirmed positive GC NAATs by performing culture (26/31). Laboratories performed dual NAAT testing on specimens sourced from both community and genitourinary medicine clinic settings, and on a wide variety of different specimen types. This survey highlights a lack of consistency in the current use of dual NAAT platforms in the UK and the need for national guidelines.

Neisseria gonorrhoeae and Chlamydia trachomatis among human immunodeficiency virus-infected women.

Neisseria gonorrhoeae and Chlamydia trachomatis among human immunodeficiency virus-infected women.