Aptima Combo Research Articles

Evaluation of the new AmpliSens multiplex real-time PCR assay for simultaneous detection of Neisseriagonorrhoeae, Chlamydiatrachomatis, Mycoplasmagenitalium, and Trichomonasvaginalis.

In this study, we performed an evaluation of the new CE-marked multiplex real-time AmpliSens N.gonorrhoeae/C.trachomatis/M.genitalium/T.vaginalis-MULTIPRIME-FRT PCR assay compared to APTIMA tests, i.e., APTIMA COMBO 2assay, APTIMA Trichomonasvaginalis assay (FDA-approved), and two different APTIMA Mycoplasmagenitalium assays (research use only; one of them only used for discrepancy analysis). Vaginal swabs (n=209) and first-void urine (FVU) specimens from females (n=498) and males (n=554), consecutive attendees (n=1261) at a dermatovenerological clinic in Sweden, were examined. The sensitivity of the AmpliSens PCR assay for detection of C.trachomatis (6.3% prevalence), M.genitalium (5.7% prevalence), N.gonorrhoeae (0.3% prevalence), and T.vaginalis (0.08% prevalence) was 97.5% (95% confidence interval (CI): 91.2-99.6%), 81.9% (95% CI: 70.7-89.7%), 100% (95% CI: 40.2-100%) and 100% (95% CI: 16.5-100%), respectively. The specificity of the AmpliSens PCR assay was 100% (95% CI: 99.6-100%) for all agents. The analytical sensitivity and specificity for N.gonorrhoeae detection was excellent, i.e., 55 international gonococcal strains detected and 135 isolates of 13 non-gonococcal Neisseria species were negative. In conclusion, the multiplex real-time AmpliSens N.gonorrhoeae/C.trachomatis/M.genitalium/T.vaginalis-MULTIPRIME-FRT PCR assay demonstrated high sensitivity and excellent specificity for the detection of C.trachomatis, N.gonorrhoeae, and T.vaginalis, and excellent specificity but suboptimal sensitivity for M.genitalium detection.

P27 Extra-genital chlamydia testing in heterosexual patients. is it worth it?

<h3>Background/introduction</h3> Current clinic policy is to offer extra-genital testing to all patients reporting a history of active oral sex and/or receptive anal sex. These swabs are analysed using the Aptima Combo II platform for <i>Chlamydia trachomatis</i> (CT). <h3>Aim(s)/objectives</h3> With analysis costing £6.20 per swab we sought to explore the cost effectiveness and review positive case with collateral contact information and symptoms history to support a positive diagnosis. <h3>Methods</h3> Inclusion criteria were heterosexual patients with exclusively extra-genital CT who did not present as CT contact. We performed retrospective case note review of 63 sets of notes to determine symptom history, concurrent STI diagnosis and contact diagnosis. <h3>Results</h3> Over the year, a total of 12076 throat swabs were sent in this group. There were 39 confirmed positive results giving swabs sent per positive result ratio of 310:1. Or a cost of £1922 per positive result. For rectal swabs; a total of 1156 were sent. There were 24 positive results giving swabs sent per positive result ratio of 48:1, or a cost of £297.60 per positive result. 5% of patients with a positive extra-genital swab result gave a history of throat or rectal symptoms. 4% had a concurrent STI diagnosis, 40% of those with traceable contacts had at least one positive contact. <h3>Discussion/conclusion</h3> Routine extra-genital screening is costly but this review demonstrates its value for detection of individual cases which would have been missed. In addition the high proportion of positive contacts adds weight to the debate for extra-genital testing of all contacts.

P28 Extra-genital gonorrhoea testing in heterosexual patients. is it worth it?

<h3>Background/introduction</h3> Current clinic policy is to offer extra-genital testing to all patients reporting a history of active oral sex and/or receptive anal sex. These swabs are analysed using the Aptima Combo II platform, for Neisseria gonorrhoea (GC). <h3>Aim(s)/objectives</h3> With analysis costing £6.20 per swab we sought to explore cost effectiveness, review culture results and partner notification results. <h3>Methods</h3> Inclusion criteria were heterosexual patients with exclusively extra-genital GC who did not present as a contact of GC. We performed a retrospective case note review of 54 sets of notes asserting symptom history, concurrent STI diagnosis, culture results and any positive contacts. <h3>Results</h3> Over the year, a total of 13123 throat swabs were sent. There were 50 confirmed positive results giving swabs sent per positive result ratio of 262:1, or a cost of £1624.40 per positive result. For rectal swabs; a total of 1362 were sent. There were 4 positive results (all female) giving swabs sent per positive result ratio of 341:1, or a cost of £2114.20 per positive result. 2% of patients with a positive extra-genital swab result gave a history of throat or rectal symptoms. 18% had a concurrent STI diagnosis, 0% had a positive culture result from the same site. 6% had at least one subsequent positive contact, all of which were pharyngeal positive. <h3>Discussion/conclusion</h3> Extra-genital testing has detected cases which would otherwise have been missed with purely genital screening. However numbers are too small to advocate a change in practice to routine extra-genital screening in all asymptomatic individuals.

Successful Combination of Nucleic Acid Amplification Test Diagnostics and Targeted Deferred Neisseria gonorrhoeae Culture.

Nucleic acid amplification tests (NAATs) are recommended for the diagnosis of N. gonorrhoeae infections because of their superior sensitivity. Increasing NAAT use causes a decline in crucial antimicrobial resistance (AMR) surveillance data, which rely on culture. We analyzed the suitability of the ESwab system for NAAT diagnostics and deferred targeted N. gonorrhoeae culture to allow selective and efficient culture based on NAAT results. We included patients visiting the STI Clinic Amsterdam, The Netherlands, in 2013. Patient characteristics and urogenital and rectal samples for direct N. gonorrhoeae culture, standard NAAT, and ESwab were collected. Standard NAAT and NAAT on ESwab samples were performed using the Aptima Combo 2 assay for N. gonorrhoeae and C. trachomatis. Two deferred N. gonorrhoeae cultures were performed on NAAT-positive ESwab samples after storage at 4°C for 1 to 3 days. We included 2,452 samples from 1,893 patients. In the standard NAAT, 107 samples were N. gonorrhoeae positive and 284 were C. trachomatis positive. The sensitivities of NAAT on ESwab samples were 83% (95% confidence interval [CI], 75 to 90%) and 87% (95% CI, 82 to 90%), respectively. ESwab samples were available for 98 of the gonorrhea-positive samples. Of these, 82% were positive in direct culture and 69% and 56% were positive in the 1st and 2nd deferred cultures, respectively (median storage times, 27 and 48 h, respectively). Deferred culture was more often successful in urogenital samples or when the patient had symptoms at the sampling site. Deferred N. gonorrhoeae culture of stored ESwab samples is feasible and enables AMR surveillance. To limit the loss in NAAT sensitivity, we recommend obtaining separate samples for NAAT and deferred culture.

Confirmatory assays are essential when using molecular testing for Neisseria gonorrhoeae in low-prevalence settings: insights from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3)

ObjectivesTo investigate the occurrence of unconfirmed positive gonorrhoea results when using molecular testing within a large population-based survey.Design, setting and participantsBetween 2010 and 2012, we did a probability sample survey...

A randomized controlled trial of the effects of a brief intervention to increase chlamydia and gonorrhea testing uptake among young adult female emergency department patients.

The objective of this study was to test the effect of a brief educational and counseling intervention on increasing the uptake of free testing for Chlamydia trachomatis (chlamydia) and Neisseria gonorrhea (gonorrhea) among young female emergency department (ED) patients. Women are particularly vulnerable to more serious consequences of these infections due to asymptomatic presentation. Increased testing is important to detect, treat, and halt the spread of these infections among asymptomatic women. This was a randomized controlled trial. Research assistants (RAs) approached female patients in two EDs. Eligible patients were between 18 and 35 years of age, who reported having sex with males, but were not attending the ED for either treatment of sexually transmitted infection (STI) or testing for possible STI exposure. Participants responded to survey questions about their lifetime and past 3-month substance use, number of recent sexual partners, condom use, and perception of risks for chlamydia and gonorrhea infections. Following the survey, the RAs randomized participants into study control or treatment arms. Each treatment arm participant received a brief educational/counseling intervention from the RA. The brief intervention focused on the woman's personal risks for chlamydia and gonorrhea and condoms attitudes and usage. As the primary outcome of this study, participants were offered free urine tests for chlamydia and gonorrhea infection postintervention or post-survey completion, depending on group assignment. A total of 171 women completed the baseline assessment and were offered chlamydia and gonorrhea testing. The mean (±SD) age was 26 (±4.76) years, 18% were Hispanic, and 12% were Spanish-speaking only. The brief intervention that was offered to increase these women's awareness of their STI risk did not result in increased acceptance of testing; 48% in the brief intervention group accepted testing (95% confidence interval [CI] = 32% to 64%) versus 36% in the control group (95% CI = 19% to 53%). In a multivariable logistic regression, only self-identifying as being Hispanic was associated with greater willingness to be tested. Of the asymptomatic women tested (n = 71), five tested positive for chlamydia. This represents a positivity rate of 7%. There were no positive test results for gonorrhea. Women who reported high-risk factors for STI, such as younger age (≤25 years), having sex in the past 90 days without using condoms, identified substance use, or previous STI, were not more likely to accept the offer of chlamydia and gonorrhea testing. The brief intervention used in this study did not increase the uptake of testing for chlamydia and gonorrhea infections in this sample, in comparison to receiving no intervention. Although Hispanic women were more likely to accept chlamydia and gonorrhea testing, it is concerning that those women who report STI risk factors were not more likely to accept the offer of chlamydia and gonorrhea testing. Future research should focus on the refinement of an intervention protocol to focus on prior STI and lack of condom use to increase the uptake of testing among this high-risk group.

Evaluation of pooled ocular and vaginal swabs by the Cepheid GeneXpert CT/NG assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae compared to the GenProbe Aptima Combo 2 Assay

Ocular swabs from Tanzania were tested for Chlamydia trachomatis (CT), and self-collected vaginal swabs collected through a home collection program, iwantthekit.org, were tested for Neisseria gonorrhoeae and CT to evaluate Cepheid GeneXpert for the use of pooling multiple specimens before testing. GeneXpert shows to be a promising test for pooling.

Evidence for increased Chlamydia case finding after the introduction of rectal screening among women attending 2 Canadian sexually transmitted infection clinics.

Chlamydia trachomatis is the most common notifiable disease in Canada, and extragenital sites are believed to serve as hidden reservoirs for ongoing transmission of infection. There are no specific Canadian screening guidelines for asymptomatic individuals from extragenital sites. We sought to determine the prevalence and factors associated with rectal C. trachomatis among female sexually transmitted infection (STI) clinic attendees in Alberta, Canada. Between 20 July and 31 December 2012, all female attendees at 2 Provincial STI clinics receiving a pelvic examination, regardless of a history of anal intercourse, were screened for rectal C. trachomatis using the Gen-Probe Aptima COMBO 2 Assay. Demographic and behavior variables were compared between rectal-only chlamydia cases and genitourinary cases using χ(2) or Fisher exact test, Mann-Whitney test, and logistic regression. A total of 3055 women were screened for rectal chlamydia. The prevalence of rectal chlamydia ranged from 11.7% to 13.5%. There were 133 rectal-only cases, increasing case detection by 44.3% from 300 genitourinary cases to 433 total cases, ranging from 21.7% to 88.2% by clinic. Women who were a contact to an STI were less likely to have rectal-only chlamydia for both clinics (P ≤ .001). Our findings add to the growing body of evidence supporting universal rectal screening in high-risk women such as those undergoing pelvic exams at STI clinics.

The Verification of Nucleic Acid Amplification Testing (Gen-Probe Aptima Assay) for Chlamydia trachomatis from Ocular Samples

Chlamydia trachomatis conjunctivitis may present with extended symptoms, and it can have social ramifications as a sexually transmitted disease. For appropriate therapy, C.trachomatis conjunctivitis should be diagnosed definitively. This study presents the verification of nucleic acid amplification testing (NAAT; Gen-Probe Aptima Combo 2 assay) for detection of C.trachomatis ribosomal RNA (rRNA) from direct ocular samples. Retrospective laboratory verification study. Patients with infectious conjunctivitis. A battery of 25 true-positive specimens (direct ocular specimens from patients with symptoms consistent with C.trachomatis conjunctivitis and with previously demonstrated positive polymerase chain reaction [PCR] results for C.trachomatis DNA by Roche Amplicor) and 25 true-negative specimens (direct ocular specimens with culture-positive results for herpes simplex virus [n= 5], adenovirus [n= 5], Haemophilus influenzae [n= 5], and Streptococcus pneumoniae [n= 5]), and transport medium (n= 5) were tested for C.trachomatis rRNA by NAAT. These true-negative specimens have differential etiologic agents of infectious conjunctivitis. The 25 C.trachomatis specimens with PCR-positive results (obtained May 1994-May 2012) and 20 true-negative infectious ocular specimens (obtained December 2008-August 2013) were collected with soft-tipped applicators and placed in transport medium. All excess specimens were stored at-80°C. All samples were centrifuged at 13,000 rpm for 1 hour at 6°C. For each sample, using the Aptima Unisex collection blue swab, a specimen was collected from the conical apex of the storage tube where a pellet was formed. The Aptima Unisex collection swab was placed in a tube of Aptima swab transport medium for testing. All samples were tested in duplicate. Detection of C.trachomatis rRNA. Of 25 true-positive samples, 24 (96%) were positive by NAAT, whereas 25 of 25 true-negative samples (100%) showed negative results. The sensitivity, specificity, positive predictive value, negative predictive value, and efficiency were determined to be 96%, 100%, 100%, 96%, and 98%, respectively. The detection of C.trachomatis in ocular specimens by NAAT was verified for laboratory diagnosis. The test will be evaluated prospectively to determine future test performance precisely.

Head-to-Head Comparison of Second-Generation Nucleic Acid Amplification Tests for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae on Urine Samples from Female Subjects and Self-Collected Vaginal Swabs

In a comparison of 4 second-generation nucleic acid amplification tests performed with self-collected vaginal swab (SCVS) and first-void urine (FVU) specimens from 575 women, SCVS specimens indicated more infections than did FVU specimens in all assays. The prevalence rates were 9% (53/575 patients) for Chlamydia trachomatis and 2% (11/575 patients) for Neisseria gonorrhoeae. The clinical sensitivities for testing SCVS specimens for C. trachomatis were 98.1% on a Tigris system and 96.2% on a Panther system for the Aptima Combo 2 assay (Hologic Gen-Probe), 98.0% for the RealTime CT/NG assay on an m2000 instrument (Abbott), 90.6% for the ProbeTec CT/GC Q(x) assay on the Viper system (Becton Dickinson), and 84.6% for the cobas CT/NG assay on the cobas 4800 platform (Roche). Clinical sensitivities for C. trachomatis in FVU specimens were 88.7% (Tigris) and 88.0% (Panther) for the Aptima Combo 2 assay, 76.9% for the RealTime CT/NG assay, 75.5% for the ProbeTec CT/GC Q(x) assay, and 81.1% for the cobas CT/NG assay. Clinical sensitivities of the assays for N. gonorrhoeae, with limited positive results, ranged from 63.6% to 100%. Specificities for both infections ranged from 98.4 to 100%. Differences in analytical sensitivities and levels of molecular targets in clinical samples but not inhibitors of amplification may explain the differences in clinical sensitivities.

Evaluation of the Hologic Gen-Probe PANTHER, APTIMA Combo 2 Assay in a Tertiary Care Teaching Hospital

To evaluate the performance of the Hologic Gen-Probe (San Diego, CA) PANTHER system. The performance of PANTHER was compared with the Hologic Gen-Probe TIGRIS and/or Roche (Indianapolis, IN) COBAS AMPLICOR systems through testing of patient specimens and the spiked-urine matrix. After discrepant resolution, PANTHER demonstrated a 99.3% (95% confidence interval [CI], 96.0%-99.9%) positive and 100% (98.5%-100.0%) negative agreement for Chlamydia trachomatis (CT) and 100% (96.6%-100.0%) positive and 100% (98.6%-100.0%) negative agreement for Neisseria gonorrhoeae (NG) for all male, female, unsexed, and NG-spiked female urine specimens combined. For other specimen types collectively, the PANTHER demonstrated 100% (95% CI, 90.6%-100.0%) positive and 100% (88.3%-100.0%) negative agreement for CT and 90.9% (62.8%-98.4%) positive and 100% (93.5%-100.0%) negative agreement for NG. Analytical sensitivity of the PANTHER in urine matrix was similar to the TIGRIS system. The PANTHER system provides an excellent new addition to options for detecting CT and NG, is appropriate for testing urine samples, and will facilitate high-throughput testing in the clinical laboratory.

Utility of Specimens Positive for Neisseria gonorrhoeae by the Aptima Combo 2 Assay for Assessment of Strain Diversity and Antibiotic Resistance

In our jurisdiction, the Aptima Combo 2 assay (Gen-Probe, Inc.) is used to detect Neisseria gonorrhoeae from specimens collected at clinics for sexually transmitted infections (STI) and from select community patients. In addition, swabs are also collected for N. gonorrhoeae culture, susceptibility testing, and sequence typing (ST). Since only a small proportion of samples from provincial cases undergo culture, the available trends in antimicrobial susceptibility and predominant strain types may not be representative of all N. gonorrhoeae infections. Due to the limitations facing the use of N. gonorrhoeae culture to understand these trends in the general community, we performed a molecular analysis for markers of cephalosporin resistance and ST determination by using nucleic acid extracts of specimens sent for Aptima testing. Thirty-four samples submitted for both Aptima testing and N. gonorrhoeae culture from the same anatomic location (within 24 h) were included in the study. Sequence type was determined based on the sequence of the por and tbpB genes, and amino acid changes in the PBP 2 protein, encoded by the penA gene, were considered representative for the assessment of antimicrobial susceptibility. Sequence identity of 100% was observed between the sequences obtained from Aptima-analyzed samples and culture samples. Sequencing results showed an association between decreased susceptibility to extended-spectrum cephalosporins (ESC(ds)), tbp allele 110, ST 1407, and amino acid changes (G545S, I312M, and V316T) in the PBP 2 protein. Our data, generated based on a few representative genes, suggest that gonococcal samples positive by Aptima testing can be used to determine single nucleotide polymorphisms associated with ESC(ds) and the sequence type based on molecular strain typing. Confirmation of these findings may obviate the need for gonorrhea culture in the future.

Experiencia con un método de autotoma de muestra vaginal para la detección de infección por Chlamydia trachomatis y Neisseria gonorrhoeae en mujeres jóvenes

Chlamydia trachomatis and Neisseria gonorrhoeae are responsible for 3-10% of sexually transmitted diseases in adolescents. 75% are asymptomatic. International standards recommend annual screening for C. trachomatis in sexually active women under 26 years. Self-collected vaginal swab is one of the less invasive screening methods, it is well accepted by patients and rarely used in our country. To determine the frequency of C. trachomatis and n. gonorrhoeae by a self-sampling method of vaginal swab and its acceptability in a group of adolescents and young adults. Women 18 to 25 years old. Vaginal samples were processed by nucleic acid amplification tests, Gen Probe APTIMA Combo2. Data were collected on sexual behavior and perception of self-sampling by survey. We studied 344 patients with an average age of 21.7 years. Detection of C. trachomatis was positive in 7.9% women and it was not found in any of the patients studied for N. gonorrhoeae. 98% considered self-sampling instructions easy to understand, 87.5% felt comfortable taking the sample. Prevalence of C. trachomatis in the study population was similar to that described in other national and international studies. N. gonorrhoeae was not found in this series, which is consistent with literature reports. The self-sampling technique of vaginal sample was well accepted by the patients. However, they were anxious about the quality of the sample. According to our results, it is important to emphasize the importance of annual detection of these pathogens and that self-sampling technique is a valid alternative.

Pooling ocular swab specimens from Tanzania for testing by Roche Amplicor and Aptima Combo 2 assays for the detection of Chlamydia trachomatis: accuracy and cost-savings

Ocular swabs collected in Tanzania were evaluated by Amplicor CT PCR and Aptima Combo2 assays for the detection of Chlamydia trachomatis to determine if pooling could be used to reduce the cost of detection. Pooling would be an accurate method and has thus far resulted in a cost-savings of 62.2%.

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...

P2.010 Performance of Xpert ® CT/NG Assay Using Residual ProbeTec ET System™ Rectal Samples

BackgroundNucleic acid amplification testing (NAAT) is the optimal method for detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC), but no commercial tests are cleared by the US Food and...

P3.121 Are We Seeing a True Rise in Neisseria Gonorrhoeae and Chlamydia Trachomatis in England in Men Who Have Sex with Men?

BackgroundThe Health Protection Agency (HPA) in England have reported the number of sexually transmitted infections (STIs) diagnosed in men who have sex with men (MSM) continues to rise. Of note,...

P5.062 An Easy to Use Real Time PCR Test For Chlamydia Trachomatis and Neisseria Gonorrhoeae Providing Results That Can Guide Treatment Choices Before the Patient Leaves the Clinic

BackgroundNew diagnostics for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) that can provide accurate, rapid, and timely results are urgently needed so that patients can be treated at the time...

P3.153 Clinical Features and Treatment Responses in 300 Pharyngeal Chlamydia Trachomatis Infections in MSM

BackgroundIn men who have sex with men (MSM), orogenital sexual practises and an increase in triple site testing have resulted in detection of pharyngeal Chlamydia trachomatis (CT) infections. Clinical features...

P5.077 Nucleic Acid Amplification Test (NAAT) Diagnostics Combined with Delayed Neisseria Gonorrhoeae Cultivation of NAAT Positive Samples Using the ESwab™ System - the Solution For Future Gonococcal Antimicrobial Susceptibility Surveillance?

BackgroundAntimicrobial resistance (AMR) in Neisseria gonorrhoeae (Ng) is a major public health problem worldwide. Nucleic acid amplification tests (NAATs) have rapidly replaced cultivation for detection of Ng. We have evaluated...