Abbott RealTime Research Articles

Abbott RealTime MTB and MTB RIF/INH assays for the diagnosis of tuberculosis and rifampicin/isoniazid resistance

BackgroundThe Abbott RealTime MTB (Abbott-RT) and Abbott RealTime MTB RIF/INH Resistance (Abbott-RIF/INH) assays have been introduced for the detection of tuberculosis (TB) and drug-resistant tuberculosis (DR-TB). We performed a systematic review and meta-analysis to assess the accuracy of Abbott-RT and Abbott-RIF/INH for the detection of TB and DR-TB. MethodsThe Ovid MEDLINE, EMBASE, Cochrane and Web of Science databases were searched to identify eligible articles for the systematic review. The pooled analyses were calculated with a bivariate model. Hierarchical summary receiver operating characteristic curves and the area under the curve (AUC) were used to summarize overall diagnostic performance. Deeks' test was performed to evaluate potential publication bias. ResultsFor the Abbott-RT assay, 9 studies including 3, 640 patients met the study criteria. The pooled sensitivity of Abbott-RT for detecting TB was 0.96 (95% CI: 0.88–0.99) and specificity was 0.97 (95% CI: 0.93–0.99). For DR-TB, four studies were included to evaluate the diagnosis accuracy of Abbott-RIF/INH. The pooled sensitivity was 0.88 (95% CI, 0.82–0.93) and specificity was 0.99 (95% CI, 0.96–0.99). No publication bias was found. ConclusionBoth Abbott-RT and Abbott-RIF/INH assays have good sensitivity, specificity and accuracy for the diagnosis of TB and DR-TB.

Multicenter evaluation of the cobas® HIV-1 quantitative nucleic acid test for use on the cobas® 4800 system for the quantification of HIV-1 plasma viral load

Background and objectivesMeasurement of HIV-1 viral load (VL) is necessary to monitor treatment efficacy in patients receiving antiretroviral therapy. We evaluated the performance of the cobas® HIV-1 quantitative nucleic acid test for use on the cobas® 4800 system (“cobas 4800 HIV-1”). MethodsLimit of detection, linearity, accuracy, precision, and specificity of cobas 4800 HIV-1, COBAS® AmpliPrep/COBAS® Taqman® HIV-1 version 2.0 (CAP/CTM HIV-1 v2) and Abbott RealTime HIV-1 were determined in one or two out of three sites. ResultsThe limit of detection of the cobas 4800 HIV-1 for 400 μL and 200 μL input volumes was 14.2 copies/mL (95% CI: 12.5–16.6 copies/mL) and 43.9 copies/mL (37.7–52.7 copies/mL), respectively. Cobas 4800 HIV-1 demonstrated 100% specificity, and results were linear for all analyzed group M HIV-1 subtypes. Precision was high (SD < 0.19 log10) across all measured ranges, reagent lots and input volumes. Correlation between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 or RealTime HIV-1 was high (R2 ≥ 0.95). Agreement between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 was 96.5% (95.0%–97.7%) at a threshold of 50 copies/mL, and 97.2% (95.8%–98.3%) at 200 copies/mL. Agreement between cobas 4800 HIV-1 and RealTime HIV-1 was 96.6% (93.4%–98.5%) at 50 copies/mL, and 97.0% (94.0%–98.8%) at 200 copies/mL. The mean difference between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 or RealTime HIV-1 was -0.10 log10 or 0.01 log10, respectively. ConclusionsThe cobas 4800 HIV-1 test is highly sensitive, accurate and correlated well with other assays, including agreement around clinically relevant thresholds, indicating minimal overall VL quantification differences between tested platforms.

Reliable resolution of ambiguous hepatitis C virus genotype 1 results with the Abbott HCV Genotype Plus RUO assay

Accurate subtyping of hepatitis C virus genotype 1 (HCV-1) remains clinically and epidemiologically relevant. The Abbott HCV Genotype Plus RUO (GT Plus) assay, targeting the core region, was evaluated as a reflex test to resolve ambiguous HCV-1 results in a challenging sample collection. 198 HCV-1 specimens were analysed with GT Plus (38 specimens with and 160 without subtype assigned by the Abbott RealTime Genotype II (GT II) assay targeting the 5’NC and NS5B regions). Sanger sequencing of the core and/or NS5B regions were performed in 127 specimens without subtype assignment by GT II, with “not detected” results by GT Plus, or with mixed genotypes/subtypes. The remaining GT Plus results were compared to LiPA 2.0 (n = 45) or just to GT II results if concordant (n = 26). GT Plus successfully assigned the subtype in 142/160 (88.8%) samples. “Not detected” results indicated other HCV-1 subtypes/genotypes or mismatches in the core region in subtype 1b. The subtyping concordance between GT Plus and either sequencing or LiPA was 98.6% (140/142). Therefore, combined use of GT II and GT Plus assays represents a reliable and simple approach which considerably reduced the number of ambiguous HCV-1 results and enabled a successful subtyping of 98.9% of all HCV-1 samples.

Prevalence of high-risk human papilloma virus in women with high-grade squamous cell intraepithelial lesions in Botswana using Abbott RealTime HPV assay.

BackgroundHigh-risk human papillomavirus (HR-HPV) has been demonstrated to be the necessary cause of cervical carcinoma. High-risk HPV detection has a prognostic significance for the women who are at increased risk of disease progression. HPV genotyping in cervical cancer precursor lesions is crucial for prevention and management of cervical cancer. This study was designed to investigate the distribution of HR-HPV genotypes among a group of patients with high-grade squamous intraepithelial lesions and higher, of the cervix, in Botswana.Materials and methods185-archived residual formalin-fixed paraffin-embedded cervical biopsies collected between the years, 2006 and 2008 were studied. These tissues were diagnosed with HSIL (n = 146) and squamous cell carcinoma (n = 39). DNA was extracted using the Abbott m2000 analyser (Abbott Laboratories, Illinois) using reagents provided by the manufacturer. HPV genotyping was done using the Abbott RealTime HR-HPV PCR, which qualitatively detects 14 HR-HPV (reported as HPV 16, 18 & Other HR-HPV).ResultsDNA was successfully extracted from 162/185 (87.6%) tissues as indicated by a positive β-globin test. 132/162 (82%) tested positive for HR-HPV The HPV 16 prevalence was 50% (66/132), HPV 18 at 15.2% (20/132) and other Group 1 HR-HPV plus HPV 66 and 68 had a prevalence of 56.1% (74/132). Other HR-HPV types were common in HSIL than in carcinoma, while HPV 16 was more prevalent in carcinomas than other HR-HPV genotypes.ConclusionIn this study, HPV 16 and other HR-HPV genotypes were commonly associated with HSIL but HPV 18 was uncommon among Botswana women. Our data highlights the need for multivalent HPV vaccines with cross coverage for other high risk HPV other than HPV 16 and 18.

Chlamydia trachomatis screening in urine among asymptomatic men attending an STI clinic in Paris: a cross-sectional study

BackgroundThe incidence of Chlamydia trachomatis (Ct) urethritis has been increasing for the past 10 years. There is little data regarding the screening of Ct infection in asymptomatic men in France, despite the national recommendation to screen at-risk asymptomatic men under 30 attending Sexually Transmitted Infections (STI) clinics. Recent data from the French surveillance network Rénachla show indeed that systematic screening is still focused on women. The objective of our study was to determine the prevalence and risk factors for Ct infection in asymptomatic men under 30 attending an STI clinic located in Paris, France.MethodsWe performed a cross-sectional study between April 4, and December 31, 2016 in the database of the software DIAMM Client V8 used in our STI clinic. We extracted the demographic characteristics, sexual behavior and result of STI screening of all asymptomatic men who had consulted and given their consent for the use of their personal data. Those data were collected in usual care through a standardized questionnaire filled in during an appointment with a trained physician. STI screening was performed using PCR kit CT/NG Abbott Realtime® on first void urines. For MSM, a rectal swab was also collected. Risk factors for Ct infection were analyzed by univariate and multivariate modeling using STATA software 8.2.ResultsAmong 872 men who had attended the clinic, 647 were included and 37 (5.7, 95% CI 4.2 to 7.8) were positive for Ct in urine. In univariate analysis, men who had unprotected sex in the last 6 weeks (OR 2.40 (95%CI 1.16 to 4.94), p = 0.02), and those who had an infected partner (OR 7.6 (95%CI 3.03 to 20), p = 0.0001) were more likely to be infected. In the multivariate analysis having an infected partner was the only risk factor (OR 11.1(95% CI 3.7 to 33.3), p = 0.0001) that remained significant.ConclusionPrevalence of Ct infection is high among asymptomatic men of 30 years or less attending our urban STI clinic especially among those with an infected partner. The Ct screening among this population associated with partner notification, as recommended by the French national guidelines, should be more widely implemented.

Evaluation of Dried Blood Spots as a Feasible Alternative to Plasma for the Detection and Quantification of Hepatitis C Virus in a Tropical Setting: A Pilot Study

AbstractIntroduction: Confirmatory diagnosis of hepatitis C virus (HCV) infection (HCV RNA detection) is essential before start of the therapy. HCV RNA detection is not available in many parts of India. Shipment of plasma from distant places to referral laboratories may affect HCV RNA titres. Dried blood spots (DBS) provide an easy alternative for transporting samples to centres where HCV RNA testing is done. Aim: Evaluation of DBS as a feasible alternative to plasma for HCV diagnosis. Methods: In this cross-sectional study, 40 consecutive patients’ blood samples were collected from patients referred from the Liver Clinic. Whole blood was spotted onto two Whatman 903TM cards. One card was incubated at ≥37°C and other at 4°C for 15 days, after drying. DBS was eluted and run in Abbott RealTime HCV assay. HCV was also quantified using the Abbott ARCHITECT HCV core antigen assay for 29 of the study patients. Results were compared with normal plasma values. Results: The median log HCV RNA value (in log10 IU/mL) of plasma was 5.74, with normalised DBS it was 4.92 (≥37°C) and 4.66 (4°C); difference in plasma and DBS median log values was 0.82 (≥37°C) and 1.08 (4°C) logs, respectively. Interclass correlation values were 0.943, P < 0.0001 (≥37°C) and 0.950, P < 0.0001 (4°C), showing high agreement. The median HCV core antigen value (in fmol/L) for plasma was 325.35, whereas it was 4.77 (≥37°C) and 4.64 (4°C) for DBS samples. Conclusions: DBS can be used for sampling patients from distant resource-limited settings as an alternative to plasma for HCV RNA estimation. Larger studies are required to evaluate the feasibility of DBS in the Indian subcontinent, especially for HCV core antigen estimation.

Take three, test one: a cross-sectional study to evaluate the molecular detection of Chlamydia trachomatis and Neisseria gonorrhoeae in pooled pharyngeal, anorectal and urine samples versus single-site testing among men who have sex with men in Belgium

ABSTRACTObjectives: To investigate the efficacy of performing a pooling strategy of triple-anatomical site samples (pharyngeal, anorectal and urine samples) for simultaneous Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) nucleic acid amplification detection.Methods: A total of 117 specimen sets (pharyngeal, anorectal and urine) were collected from 98 men between 2014 and 2016. Double sampling of pharyngeal, anorectal and urine samples allowed for pooled and unpooled analyses using a multiplex Abbott Real Time CT/NG assay, together with confirmatory PCR testing in case of CT/NG positivity. Clinical and demographic data were analyzed.Results: The positivity rate for the triple-site pooled testing for CT and NG was 8.5% (10/117) and 6.8%, (8/117), respectively, compared to the single-site testing total positivity rate, which was 9.4% (11/117) and 4.3% (5/117) for CT and NG, respectively. Pooled analysis missed one CT-positive urine sample and one CT-positive anorectal sample could not be confirmed. In addition, less PCR inhibition was reported for the pooled sample (PS) testing and ERV-3 qPCR testing revealed ineffective sampling of self-collected anorectal swabs in two cases. No pharyngeal samples were positive for CT, nor were any urine samples positive for NG.Conclusion: This small study showed that PS testing is a possible testing strategy for screening high-risk men who have sex with men attending pre-exposure prophylaxis (PrEP) clinics. However, due to the low positivity rate of CT/NG in this study, larger evaluations are needed to confirm the effectiveness of CT/NG screening with multiple-site PS nucleic acid amplification test (NAAT) screening practices.

Novel homo Yin-Yang probes improve sensitivity in RT-qPCR detection of low copy HIV RNA

Nucleic acids labeled with a fluorophore/quencher pair are widely used as probes in biomedical research and molecular diagnostics. Here we synthesized novel DNA molecular beacons double labeled with the identical dyes (R6G, ROX and Cy5) at 5′- and 3′-end and studied their photo physical properties. We demonstrated that fluorescence quenching by formation of the homo dimer exciton in such molecular beacons allows using them in homogeneous assays. Further, we developed and evaluated homo Yin-Yang DNA probes labeled with identical dyes and used them for detection of low copy HIV RNA by RT-qPCR. They demonstrated improved sensitivity (LLQ: 10 vs 30 copies mL-1) in comparison to commercially available Abbott RealTime HIV-1 kit based on VIC-BHQ dyes both for model mixtures (naive human plasma with added deactivated HIV-1 virus) and for preliminarily confirmed 36 clinical samples (4 vs 1 positive ones for low-copy samples).

Performance comparison of new Veris and Xpert random access HIV-1 RNA quantification assays

BackgroundRecent systems for Human Immunodeficiency Virus 1 (HIV-1) viral load (VL) monitoring allow one-by-one analysis and fast turn-around-time for results. VL measurement on two rapid recently commercialized systems, GeneXpert (Cepheid) and Veris (Beckman Coulter) was compared to classical methods.MethodsPlasma specimen from HIV-1 (group M) positive patients (n = 129) initially quantified with Abbott RealTime HIV-1 and Generic HIV-VL Biocentric assays were retrospectively tested with GeneXpert and Veris.ResultsValid results on all techniques were obtained for 116/129 specimens composed of 89 Abbott quantifiable VL (38 B, 51 non-B subtypes) [range: 2.09–7.20 log cp/mL] and 27 plasma (9 B, 18 non-B) with Abbott-VL below the limit of quantification (LLQ). All techniques showed good correlation and agreement with a lowest Spearman correlation coefficient of 0.86. Compared to Abbott, the mean bias was 0.35 (95% CI: 0.25–0.45), 0.44 (0.36–0.53) and − 0.04 (− 0.13–0.05) for Biocentric, Beckman and Cepheid, respectively. A difference over 0.5 log cp/mL between VL-quantification of the same sample was observed for 19, 9 and 6 samples with Biocentric, Beckman and Cepheid, respectively. No influence of HIV-1 subtypes on VL was identified. Among 29 samples below LLQ on Abbott, only one was detected and quantified with the Veris assay (38 cp/mL), none with Cepheid.ConclusionBoth random access systems from Cepheid and Beckman appear well designed for quantifying plasma HIV-1 VL, are easy to handle, fast and fully automated. The slight observed differences suggest to follow the current guidelines recommending the use of the same technique over time for patient viral load monitoring.

Impact of HIV-1 primary drug resistance on the efficacy of a first-line antiretroviral regimen in the blood of newly diagnosed individuals in Bamako, Mali.

To achieve the 90-90-90 targets assigned by UNAIDS, it is crucial to monitor ART in HIV-1-infected patients, especially in resource-limited countries. To evaluate the immunovirological response after 12 months of ART in newly HIV-1-diagnosed people in Bamako, Mali; to determine primary and acquired resistance rates to antiretroviral drugs; and to evaluate the impact of primary resistance on the efficacy of ART. One hundred and nineteen HIV-1-infected people (88.2% women; median age 34 years) were enrolled between January and June 2014. HIV-1 RNA loads (Abbott RealTime HIV-1 assay) were tested in the blood before and at months 3, 6 and 12 after initiation of ART. Primary and acquired resistances to ART were evaluated by the Viroseq™ HIV-1 genotyping assay. During the study, 8.4% of people died and 37% were lost to follow-up. After 1 year of ART, an undetectable HIV-1 RNA viral load was found in 87.7% of cases. The overall rate of primary drug resistance mutations was 17.5% (3.2%, 15.9% and 0% for NRTIs, NNRTIs and PIs, respectively). These mutations were not associated with either higher mortality rates or larger numbers of virological failures. The acquired resistance rate was estimated at 3.1%. Our study showed a high primary resistance level and a huge proportion of people non-adherent to the treatment programme. Reassuringly, almost 90% virological success and a low level of acquired mutations were observed in adherent people at month 12. Reinforced education, regular virological monitoring and early HIV-1 diagnosis may help to improve retention in the care system.

Hepatitis C virus surveillance and identification of human pegivirus 2 in a large Cameroonian cohort

SummaryThe prevalence of chronic hepatitis C virus (HCV) and the presence of human pegivirus 2 (HPgV‐2) have not been examined in Cameroon, although HCV has been associated with HPgV‐2 infections previously. Herein we aimed to characterize the burden and genetic diversity of HCV and the presence of HPgV‐2 in Cameroon. Retrospective plasma specimens collected from N = 12 369 consenting subjects in South Cameroon from 2013 to 2016 were included in the study. The majority (97.1%) of participants were patients seeking health care. All specimens were screened for HCV using the Abbott RealTime HCV viral load assay and positive specimens with remaining volume were also screened for HPgV‐2 antibodies on the Abbott ARCHITECT instrument, followed by molecular characterization. Overall, HCV RNA was detected in 305 (2.47%; 95% CI: 2.21%‐2.75%) specimens. Notably, the prevalence of HCV RNA was 9.09% amongst participants over age 40 and 3.81% amongst males. Phylogenetic classification of N = 103 HCV sequences identified genotypes 1 (19.4%), 2 (15.5%) and 4 (65.1%) within the study cohort. Amongst HCV RNA‐positive specimens, N = 28 (10.6%; 95% CI: 7.44%‐14.90%) specimens also had detectable HPgV‐2 antibodies. Of these, N = 2 viremic HPgV‐2 infections were confirmed by sequencing and shared 93‐94 median % identity with strains found on other continents. This is the first study to determine the prevalence of chronic HCV in Cameroon, and the discovery of HPgV‐2 in this study cohort expands the geography of HPgV‐2 to the African continent, indicating a widespread distribution exists.

Hepatitis B Virus Serum DNA andRNA Levels in Nucleos(t)ide Analog-Treated or Untreated Patients During Chronic and Acute Infection.

Treatment of chronic hepatitis B (CHB) patients with nucleos(t)ide analogs (NAs) suppresses hepatitis B virus (HBV) DNA synthesis but does not affect synthesis of HBV pregenomic RNA (pgRNA). Hepatitis B virus pgRNA is detectable in the serum during NA treatment and has been proposed as a marker of HBV covalently closed circular DNA activity within the infected hepatocyte. We developed an automated assay for the quantification of serum HBV pgRNA using a dual-target real-time quantitative PCR approach on the Abbott m2000sp/rt system. We demonstrate accurate detection and quantification of serum HBV RNA. Hepatitis B virus DNA was quantified using the Abbott RealTime HBV viral load assay. We further compared serum nucleic acid levels and kinetics in HBV-positive populations. Samples included on-therapy CHB samples (n = 16), samples (n = 89) from 10 treatment naïve CHB subjects receiving 12 weeks of NA treatment with 8-week follow-up, hepatitis B surface antigen-positive blood donor samples (n = 102), and three seroconversion series from plasmapheresis donors (n = 79 samples). Conclusion: During NA treatment of CHB subjects, we observed low correlation of HBV DNA to pgRNA levels; pgRNA concentration was generally higher than HBV DNA concentrations. In contrast, when NA treatment was absent we observed serum pgRNA at concentrations that correlated to HBV DNA and were approximately 2 log lower than HBV DNA. Importantly, we observe this trend in untreated subject samples from both chronic infections and throughout seroconversion during acute infection. Results demonstrate that the presence of pgRNA in serum is part of the HBV lifecycle; constant relative detection of pgRNA and HBV DNA in the serum is suggestive of a linked mechanism for egress for HBV DNA or pgRNA containing virions.

Prevalence and correlates of and a risk score to identify asymptomatic anorectal gonorrhoea and chlamydia infection among men who have sex with men in Kisumu, Kenya

ObjectivesIn settings where laboratory capacity is limited, the WHO recommends presumptive treatment for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) in asymptomatic men who have sex with men (MSM) at...

Clinical significance of detectable and quantifiable HCV RNA at the end of treatment with ledipasvir/sofosbuvir in GT1 patients.

AASLD/IDSA treatment guidelines for hepatitis C virus (HCV) infection state that testing for quantitative HCV RNA can be considered at the end of antiviral treatment (EOT) with interferon-free regimens. However, it remains unclear how to respond to a detectable or even quantifiable HCV RNA result. The aim of this study was to analyse the frequency and predictive value of detectable and quantifiable HCV RNA results at the EOT in patients with HCV genotype 1 infection treated with ledipasvir (LDV) and sofosbuvir (SOF)±ribavirin (RBV) in a large real-world cohort. A retrospective analysis of the DHC-R (Deutsches Hepatitis C-Register, German Hepatitis C-Registry) cohort was performed including all patients who were treated with LDV/SOF±RBV and in whom HCV RNA testing was done with either the Roche COBAS AmpliPrep/COBAS TaqMan (CAP/CTM) or the Abbott RealTime HCV assay (ART). The frequency of detectable HCV RNA at the EOT was 7% in this real-world study involving 471 patients. Furthermore, 3% of the patients (n=14/471) even had quantifiable viral load at the EOT. Detectable and quantifiable results were more frequent if the ART was used for testing. However, SVR was achieved by 32/33 patients (97%) with detectable and even by all 14 patients (100%) with quantifiable HCV RNA results at the EOT. Detectable and even quantifiable HCV RNA results are quite frequent if highly sensitive HCV RNA assays are used. However, treatment prolongation is not indicated, as SVR rates remain high in these patients.

Secret intake of antiretroviral treatment and HIV-1 viremia in a public routine clinic in Burkina Faso: a surprising relationship

ABSTRACTIn sub-Saharan Africa, where people living with HIV are frequently stigmatized, the intake of antiretroviral treatment (ART) remains a critical issue for many patients. Although the secret intake of ART may hinder the adherence to treatment, data on its specific impact on therapeutic effectiveness are lacking. We therefore assessed the association between secret intake of ART (i.e., hidden from family) and HIV-1 viremia among patients treated in a public routine clinic in Burkina Faso. We performed a cross-sectional study from December 2012 to September 2013 among patients on ART at the Day Care Unit in Bobo Dioulasso. Patients were eligible for the study if they were 15 years old or over, infected with HIV-1 or HIV-1 + 2, and on ART for at least six months. HIV-1 viral load was measured using Biocentric or Abbott Real Time assay. Study-specific data were collected by social workers using face-to-face interviews, and medical data using the routine electronic database. The association between secret intake of ART and viral load >300 copies/mL was assessed using a multivariate logistic regression. Of 771 patients (women 81.4%; median age 41 years; median time on ART 51 months), 408 reported secret intake of ART and 363 declared open intake. Compared to the latter, patients who hid their intake were younger, more likely to be women and to be involved in a polygamist or in a non-cohabiting union. Viremia was observed in 4.4% of patients hiding ART intake and 9.4% of those taking it openly. By multivariate analysis, secret intake of ART was significantly associated with a lower risk of viremia (adjusted odds ratio 0.41, 95% confidence interval 0.22–0.76). The unexpected relation between secret intake of ART and viremia found in this study requires further investigations. Quantitative and qualitative studies need to be performed.

Ocular Chlamydia trachomatis Infection Under the Surgery, Antibiotics, Facial Cleanliness, and Environmental Improvement Strategy in Amhara, Ethiopia, 2011-2015.

BackgroundWorld Health Organization (WHO) recommendations for starting and stopping mass antibiotic distributions are based on a clinical sign of trachoma, which is indirectly related to actual infection with the causative agent, Chlamydia trachomatis.MethodsThis study aimed to understand the effect of SAFE (surgery, antibiotics, facial cleanliness, and environmental improvement) interventions on ocular chlamydia in Amhara, Ethiopia, by describing the infection prevalence in a population-based sample of children aged 1–5 years. Trachoma surveys were conducted in all districts of Amhara, from 2011 to 2015 following approximately 5 years of SAFE. Ocular swabs were collected from randomly selected children to estimate the zonal prevalence of chlamydial infection. The Abbott RealTime polymerase chain reaction assay was used to detect C. trachomatis DNA.ResultsA total of 15632 samples were collected across 10 zones of Amhara. The prevalence of chlamydial infection in children aged 1–5 years was 5.7% (95% confidence interval, 4.2%–7.3%; zonal range, 1.0%–18.5%). Chlamydial infection and trachomatous inflammation–intense (TI) among children aged 1–9 years were highly correlated at the zonal level (Spearman correlation [r] = 0.93; P < .001), while chlamydial infection and trachomatous inflammation–follicular were moderately correlated (r = 0.57; P = .084).ConclusionsAfter 5 years of SAFE, there is appreciable chlamydial infection in children aged 1–5 years, indicating that transmission has not been interrupted and that interventions should continue. The sign TI was highly correlated with chlamydial infection and can be used as a proxy indicator of infection.

Performance of the Abbott RealTime MTB RIF/INH resistance assay when used to test Mycobacterium tuberculosis specimens from Bangladesh.

IntroductionThe Abbott RealTime MTB RIF/INH Resistance Assay (RT MTB RIF/INH) is an assay for the detection of rifampicin (RIF)- and/or isoniazid (INH)-resistant Mycobacterium tuberculosis (MTB). The assay can be used to test sputum, bronchial alveolar lavage, and N-Acetyl-L-Cysteine (NALC)/NaOH pellets prepared from these samples. The assay can be used in direct testing mode, or in reflex mode following a MTB positive result produced by its companion assay, Abbott RT MTB.MethodsIn this study, the direct testing mode was used to test paired sputum and NALC/NaOH pellets prepared from sputum collected from Bangladesh TB patients. One hundred and thirty two paired samples were tested.ResultsThe RT MTB RIF/INH inhibition rate was 0%. One hundred and twenty-two paired samples had results above the assay limit of detection and were analyzed by comparing with results from phenotypic drug sensitivity testing, GeneXpert MTB/RIF (Xpert), and MTBDR plus (Hain). RT MTB RIF/INH results were in good agreement with those of GeneXpert and Hain.ConclusionThe ability of this assay to detect RIF and INH resistance may contribute to the global control of multidrug resistant tuberculosis.

Indeterminate genotypes of hepatitis C virus by the Abbott RealTime HCV Genotype II assay in Morocco. About eight cases resolved by a sequencing method.

The early detection and genotyping of the hepatitis C virus (HCV) are important in the management of this infection. The genotype is the major factor influencing treatment decisions. That's why it is necessary to use fast and accurate methods in its determination. This study reports, over a period of 3 years (from May 2012 to July 2015), the percentage of indeterminate genotypes by the Abbott RealTime HCV Genotype II test and their results using a sequencing technique. Of 309 samples of 309 patients tested, 11 were indeterminate (4.4%). There were three cases of cross-reactivity (1b/4 in one case, 2/5 in two cases) and a possible co-infection 1 + 4. Among those indeterminate genotypes, cross-reactivities and co-infections, ten samples were tested by sequencing. The results were for four of them a 1d subtype, five were a 2i subtype and one was a 2l subtype. These results support the thesis of complementarity between the two methods: genotyping for the detection of mixed reactions and sequencing for resolving indeterminate cases by genotyping.

Significance of detectable HCV RNA below the limit of quantification in patients treated with DAAs using standard and ultrasensitive protocols

Predictive factors of HCV relapse after treatment with DAAs are poorly understood. In this study, we aimed to assess whether the residual viral load positivity observed during or at the end of treatment (EOT) has an impact on viral outcome. Blood samples were collected from 337 patients with genotypes (GT) 1a, 1b, 2, 3, and 4 HCV chronic infection, treated with DAAs to determine HCV RNA load by the Abbott RealTime HCV (ART) assay at treatment week (W) 4, at EOT, and 4, 12, 24 weeks after discontinuation. EOT and other samples with "detected <12/mL" (DNQ) were retested by an ultrasensitive protocol (USP) to confirm the result. Frequency of DNQ was analyzed in subgroups of patients and clinical conditions to assess potential correlations. At W4, 22% and 30.9% of the samples were undetectable and DNQ by ART assay, respectively, but no correlation for achieving SVR was found. In contrast, an HCV RNA cut-off of ≥50/mL at W4 was a significant predictor of therapy failure (P = 0.036, univariate analysis). At EOT, DNQ was associated to 12W treatment duration (P < 0.001) and GT1a infection (P = 0.036). Overall, 20/41 (48.8%) of DNQ samples at EOT or post-treatment W4, were confirmed by USP but only in a single case the patient experienced viral relapse. HCV RNA at W4 can predict SVR, irrespective to genotype or DAA regimen. HCV RNA DNQ at EOT is associated to shorter treatment duration and to GT1a, but is not a predictor of therapy failure.

Development and clinical validation of the Genedrive point-of-care test for qualitative detection of hepatitis C virus

ObjectiveRecently approved direct acting antivirals provide transformative therapies for chronic hepatitis C virus (HCV) infection. The major clinical challenge remains to identify the undiagnosed patients worldwide, many of whom live...