Utility of Xpert Ultra on Different Respiratory Specimens in Children.
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ABSTRACT:
SUBMITTER: Jain S
PROVIDER: S-EPMC7258649 | biostudies-literature | 2020 Jun
REPOSITORIES: biostudies-literature
Publications
Utility of Xpert Ultra on Different Respiratory Specimens in Children.
Jain Saurav S Kumar Prawin P Goyal Jagdish Prasad JP
American journal of respiratory and critical care medicine 20200601 11
Similar Datasets
Project description: Not available
| S-EPMC7258642 | biostudies-literature
Project description:BackgroundThe Xpert MTB/RIF assay (Xpert) is an automated molecular test for the detection of tuberculosis and rifampin resistance (RIF-R), but it lacks sensitivity in smear-negative samples and some limitations in determination of RIF-R have also been reported. The new Xpert MTB/RIF Ultra (Ultra) was developed to overcome these limitations. We aimed to compare Ultra and Xpert diagnostic accuracy setting culture and drug susceptibility testing as reference standards.MethodsA retrospective analysis was performed on 359 consecutive, respiratory (269) and extrapulmonary (90) specimens collected from 340 patients investigated for TB along a two-year period. Patients presenting at primary health-care centres and hospitals were recruited on the basis of symptoms and abnormal X-ray imaging. One-hundred seventy-four subjects were identified to have active tuberculosis by culture and 2 were MDR.FindingsSensitivities of Ultra and Xpert were 87% and 75% for the 48 individuals with smear-negative and culture-positive respiratory TB (difference of 12%, 95% CI 3 to 21); 95% and 72% for the 40 individuals with smear-negative and culture-positive extrapulmonary disease (22%, 95% CI 10 to 34); and 95% and 86%, respectively, across all 174 individuals with culture-positive samples (8.5%, 95% CI 4.5 to 12.5). Specificities of Ultra and Xpert for tuberculosis case detection were 98% and 100% (-2.0%, 95% CI -4.3 to +0.3). Ultra and Xpert performed equal in detecting RIF-R.InterpretationSensitivity of Ultra was superior to that of Xpert in all categories of clinical samples. However, improved sensitivity was associated with a modest reduction in specificity.
| S-EPMC6830143 | biostudies-literature
Project description:BackgroundThe World Health Organization recommends the Xpert MTB/RIF Ultra assay for diagnosing pulmonary tuberculosis (PTB) in children. Though stool is a potential alternative to respiratory specimens among children, the diagnostic performance of Xpert Ultra on stool is unknown. Thus, we assessed the diagnostic performance of Xpert Ultra on stool to diagnose PTB in children.MethodsWe conducted a cross-sectional study among consecutively recruited children (< 15 years of age) with presumptive PTB admitted in 4 tertiary care hospitals in Dhaka, Bangladesh, between January 2018 and April 2019. Single induced sputum and stool specimens were subjected to culture, Xpert, and Xpert Ultra. We considered children as bacteriologically confirmed on induced sputum if any test performed on induced sputum was positive for Mycobacterium tuberculosis and bacteriologically confirmed if M. tuberculosis was detected on either induced sputum or stool.ResultsOf 447 children, 29 (6.5%) were bacteriologically confirmed on induced sputum and 72 (16.1%) were bacteriologically confirmed. With "bacteriologically confirmed on induced sputum" as a reference, the sensitivity and specificity of Xpert Ultra on stool were 58.6% and 88.1%, respectively. Xpert on stool had sensitivity and specificity of 37.9% and 100.0%, respectively. Among bacteriologically confirmed children, Xpert Ultra on stool was positive in 60 (83.3%), of whom 48 (80.0%) had "trace call."ConclusionsIn children, Xpert Ultra on stool has better sensitivity but lesser specificity than Xpert. A high proportion of Xpert Ultra assays positive on stool had trace call. Future longitudinal studies on clinical evolution are required to provide insight on the management of children with trace call.
| S-EPMC8521743 | biostudies-literature
Project description:OBJECTIVE: To assess Xpert® MTB/RIF (Xpert) and Xpert® MTB/RIF Ultra (Ultra) performance in diagnosing pediatric tuberculous meningitis (TBM).METHODS: We conducted a study among children with suspected meningoencephalitis in Pune, India. Clinical, radiological, laboratory, and treatment data were analyzed to classify disease as definite, probable, possible or no TBM, using microbiologic or composite reference standards. We tested cerebrospinal fluid (CSF) either using Xpert or Ultra and estimated test performance characteristics.RESULTS: Of 341 participants, 149 (43.7%) were tested using Ultra and 192 (56.3%) with Xpert. Ultra had higher sensitivity (50% vs. 18%), lower specificity (91% vs. 99%), poor positive predictive value (PPV) (13% vs. 75%), and higher negative predictive value (NPV) (99% vs. 93%) than Xpert using the composite reference standard, with similar results by the microbiologic reference standard. Of 10 participants with trace positivity on Ultra, none met clinical TBM definitions.CONCLUSION: This is the first study to report on diagnostic performance of Ultra in pediatric TBM, which showed higher sensitivity and NPV than Xpert. For children presenting with nonspecific clinical features, Ultra is a promising diagnostic test. Further studies are required to define its optimal clinical use, including interpretation of trace positive results.
| S-EPMC9592112 | biostudies-literature
Project description:Merkel cell polyomavirus (MCPyV) DNA was detected in 7 (1.3%) of 526 respiratory tract samples from patients in Australia with upper or lower respiratory tract symptoms. Partial T antigen and major capsid protein sequences of MCPyV identified in respiratory secretions showed high homology (99%-100%) to those found in Merkel cell carcinoma.
| S-EPMC2681122 | biostudies-literature
Project description:BackgroundTuberculosis (TB) diagnosis in the UK is impacted by delay and suboptimal culture-based microbiological confirmation rates due to the high prevalence of paucibacillary disease. We examine the real-world clinical utility of Xpert MTB/RIF Ultra (Xpert-Ultra) as a diagnostic test and biomarker of transmissible infection in a UK TB service.MethodsClinical specimens from suspected TB cases triple tested (smear microscopy, mycobacterial culture and Xpert-Ultra) at University Hospitals of Leicester NHS Trust (1 March 2018-28 February 2019) were retrospectively analysed. Diagnostic sensitivity and specificity were calculated using positive MTB culture and clinical TB diagnosis as reference standards. The QuantiFERON (QFT) positive proportion of pulmonary TB (PTB) contacts was used as a metric of transmitted infection to evaluate Xpert-Ultra and smear grade as markers of infectiousness.Results251 samples (188 respiratory) from 231 patients (86 TB) were analysed. Compared with microscopy, Xpert-Ultra had higher diagnostic sensitivity (24.7% vs 78.7%, p<0.001) and comparable specificity (97.5% vs 99.4%). Xpert-Ultra and culture had comparable sensitivity (78.7% vs 71.9%) and specificity (99.4% vs 100.0%). Incorporating Xpert-Ultra with culture increased microbiologically verified diagnosis to 91.7% for PTB and 75.9% for extrapulmonary TB, compared with 85.0% and 44.8%, using culture alone. In PTB, both smear and Xpert-Ultra grade were positively associated with the proportion of contacts testing QFT positive. However, Xpert-Ultra had a higher negative predictive value than smear (QFT-positive contacts 6.7% vs 17.7%).ConclusionIn low-TB-burden settings, systematic adoption of Xpert-Ultra for clinical assessment of suspected TB can improve the proportion of microbiologically verified diagnoses and improve the stratification of transmission risk.
| S-EPMC11751901 | biostudies-literature
Project description: Not available
| S-EPMC6555588 | biostudies-literature
Project description:The availability of syndrome-based panels for various ailments has widened the scope of diagnostics in many clinical settings. These panels can detect a multitude of pathogens responsible for a particular condition, which can lead to a timely diagnosis and better treatment outcomes. In contrast to traditional identification methods based on pathogen growth on culture, syndrome-based panels offer a quicker diagnosis, which can be especially beneficial in situations requiring urgent care, such as intensive care units. One such panel is the Biofire Filmarray Pneumonia plus Panel (BFP), which we have compared against microbiological culture and identification. The lower respiratory samples from patients were tested with BFP, culture, and identification with culture considered the gold standard. The phenotypic antibiotic susceptibility results (Vitek 2) were compared with the antimicrobial resistance (AMR) genes detected in BFP. Statistical analysis was carried out using GraphPad 7.0 and MS Excel (Microsoft Inc.). The results showed a positive percent agreement of 100% and a negative percent agreement of 47.8% with an overall agreement of 76.72% compared to culture. BFP was better at identifying fastidious bacteria, and the agreement with culture was higher for high bacterial identification numbers (107 and 106). There was also a correlation between the number of pathogens detected and growth in culture. Carbapenemase genes were detected in around 80% of phenotypically resistant samples and correlated with in-house PCR 60% of the time. Hence, BFP results need to be interpreted with caution especially when multiple pathogens are detected. Similarly, the presence or absence of AMR genes should be used to guide the therapy while being watchful of unusual resistance or susceptibility. The cost constraints and low throughput call for patient selection criteria and prioritization in emergency or resource-limited conditions.IMPORTANCEApplication of syndrome-based panels in clinical microbiology is of huge support in infectious conditions requiring urgent interventions, such as pneumonia. Interpreting the results requires caution; hence, we have compared the results obtained from Biofire Filmarray Pneumonia plus Panel with standard microbiological methods.
| S-EPMC11237763 | biostudies-literature
Project description: Not available
| S-EPMC8078545 | biostudies-literature
Project description:The determinants of Xpert MTB/RIF sensitivity, a widely used PCR test for the diagnosis of tuberculosis (TB) are poorly understood. We compared culture time-to-positivity (TTP; a surrogate of bacterial load), MTB/RIF TB-specific and internal positive control (IPC)-specific C(T) values, and clinical characteristics in patients with suspected TB who provided expectorated (n = 438) or induced sputum (n = 128), tracheal aspirates (n = 71), bronchoalveolar lavage fluid (n = 152), pleural fluid (n = 76), cerebral spinal fluid (CSF; n = 152), pericardial fluid (n = 131), or urine (n = 173) specimens. Median bacterial load (TTP in days) was the strongest associate of MTB/RIF positivity in each fluid. TTP correlated with C(T) values in pulmonary specimens but not extrapulmonary specimens (Spearman's coefficient 0.5043 versus 0.1437; p = 0.030). Inhibition affected a greater proportion of pulmonary specimens than extrapulmonary specimens (IPC C(T) > 34: 6% (47/731) versus 1% (4/381; p < 0.0001). Pulmonary specimens had greater load than extrapulmonary specimens [TTPs (interquartile range) of 11 (7-16) versus 22 (18-33.5) days; p < 0.0001]. HIV-infection was associated with a decreased likelihood of MTB/RIF-positivity in pulmonary specimens but an increased likelihood in extrapulmonary specimens. Mycobacterial load, which displays significant variation across different body compartments, is the main determinant of MTB/RIF-positivity rather than PCR inhibition. MTB/RIF C(T) is a poor surrogate of load in extrapulmonary specimens.
| S-EPMC5375978 | biostudies-literature