Introduction Despite the limited evidence for its effectiveness, thermal screening at points of entry has increasingly become a standard protocol in numerous parts of the globe in response to the COVID-19 pandemic. We sought to determine the effectiveness of thermal screening as a key step in diagnosing COVID-19 in a resource-limited setting. Materials and methods This was a retrospective cross-sectional study based on a review of body temperature and Xpert Xpress SARS CoV-2 test results records for truck drivers entering Uganda through Mutukula between 15th May and 30th July 2020. All records missing information for body temperature, age, gender, and Xpert Xpress SARS CoV-2 status were excluded from the data set. A data set of 7,181 entries was used to compare thermal screening and Xpert Xpress SARS CoV-2 assay test results using the diagnostic statistical test in STATAv15 software. The prevalence of COVID-19 amongst the truck drivers based on Xpert Xpress SARS CoV-2 assay results was determined. The sensitivity, specificity, positive predictive value, negative predictive value, positive and negative Likelihood ratios were obtained using Xpert Xpress SARS CoV-2 assay as the gold standard. Results Based on our gold standard test, the proportion of persons that tested positive for COVID-19 was 6.7% (95% CI: 6.1–7.3). Of the 7,181 persons that were thermally screened, 6,844 (95.3%) were male. The sample median age was 38 years (interquartile range, IQR: 31–45 years). The median body temperature was 36.5°C (IQR: 36.3–36.7) and only n (1.2%) had a body temperature above 37.5°C. The sensitivity and specificity of thermal screening were 9.9% (95% CI: 7.4–13.0) and 99.5% (95% CI: 99.3–99.6) respectively. The positive and negative predictive values were 57.8 (95% CI: 46.5–68.6) and 93.9 (95% CI: 93.3–94.4) respectively. The positive and negative Likelihood Ratios (LRs) were 19 (95% CI: 12.4–29.1) and 0.9 (95% CI: 0.88–0.93) respectively. Conclusion In this study population, the use of Thermal screening alone is ineffective in the detection of potential COVID-19 cases at point of entry. We recommend a combination of screening tests or additional testing using highly sensitive molecular diagnostics such as Polymerase Chain Reaction.
Background Second-line drug resistance (SLD) among tuberculosis (TB) patients is a serious emerging challenge towards global control of the disease. We characterized SLD-resistance conferring-mutations among TB patients with rifampicin and/or isoniazid (RIF and/or INH) drug-resistance tested at the Uganda National TB Reference Laboratory (NTRL) between June 2017 and December 2019. Methods This was a descriptive cross-sectional secondary data analysis of 20,508 M. tuberculosis isolates of new and previously treated patients’ resistant to RIF and/or INH. DNA strips with valid results to characterise the SLD resistance using the commercial Line Probe Assay Genotype MTBDRsl Version 2.0 Assay (Hain Life Science, Nehren, Germany) were reviewed. Data were analysed with STATAv15 using cross-tabulation for frequency and proportions of known resistance-conferring mutations to injectable agents (IA) and fluoroquinolones (FQ). Results Among the eligible participants, 12,993/20,508 (63.4%) were male and median (IQR) age 32 (24–43). A total of 576/20,508 (2.8%) of the M. tuberculosis isolates from participants had resistance to RIF and/or INH. These included; 102/576 (17.7%) single drug-resistant and 474/576 (82.3%) multidrug-resistant (MDR) strains. Only 102 patients had test results for FQ of whom 70/102 (68.6%) and 01/102 (0.98%) had resistance-conferring mutations in the gyrA locus and gyrB locus respectively. Among patients with FQ resistance, gyrAD94G 42.6% (30.0–55.9) and gyrA A90V 41.1% (28.6–54.3) mutations were most observed. Only one mutation, E540D was detected in the gyrB locus. A total of 26 patients had resistance-conferring mutations to IA in whom, 20/26 77.0% (56.4–91.0) had A1401G mutation in the rrs gene locus. Conclusions Our study reveals a high proportion of mutations known to confer high-level fluoroquinolone drug-resistance among patients with rifampicin and/or isoniazid drug resistance. Utilizing routinely generated laboratory data from existing molecular diagnostic methods may aid real-time surveillance of emerging tuberculosis drug-resistance in resource-limited settings.
Introduction: The novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that causes COVID-19 disease is a global challenge. Several countries have adopted testing, isolation, and tracing strategy towards the control of the COVID-19 pandemic, but access to rapid and accurate testing is still a global challenge. The conventional PCR – based assay is the most commonly used test yet it has huge costs, infrastructural, and procurement logistical challenges. The Xpert® Xpress SARS-CoV-2 test is an automated in – vitro diagnostic test for the qualitative detection of nucleic acid from SARS-CoV-2 within a turnaround time of 60 minutes on the widely used GeneXpert Dx Instrument Systems. Here we document the best practices and challenges encountered with the operationalization of Xpert® Xpress SARS-CoV-2 testing in a resource-limited setting.Materials and Methods: The Xpert® Xpress SARS-CoV-2 implementation followed an operational work plan that included; Laboratory COVID-19 policy and planning, situational analysis of the Laboratory network, country Xpert® Xpress SARS-CoV-2 assay verification, and rollout at Mutukula Port Health Laboratory. The Laboratory strategy was based on a set of six objectives; conducting infrastructural modifications, building a strong COVID-19 testing capacity, developing robust Laboratory Quality and Information Management Systems, establishing a Bio-risk management and Bio-banking capacity.Results: The Xpert® Xpress SARS-CoV-2 testing implementation team that was appointed by the Ministry of Health (Uganda) successfully established the Xpert® Xpress SARS-CoV-2 testing Laboratory at Mutukula border in Uganda. As of 9th July 2020, this Laboratory had tested a total of 10,990 samples with a median turnaround time of 75 (IQR: 60 – 75) minutes for samples of persons entering through Mutukula Land Point of Entry as compared to the median TAT 1980 minutes before it was established. The laboratory had only one discordant result out of 20 panels in the inter-laboratory comparison retesting program.Conclusions: Implementation of Xpert® Xpress SARS-CoV-2 testing for rapid diagnosis of COVID-19 is feasible and significantly reduces the long TAT observed with conventional RT-PCR based testing. The operationalization of the Xpert® Xpress SARS-CoV-2 testing is largely dependent on the initial planning, adequacy of resources, and preparedness within the laboratory network. Challenges include; the difference in approaches to COVID-19 response, the attitude of truck-drivers/persons on Infection Prevention and Control measures, language barrier, and waste management issues.
Background Smear microscopy has remained the initial diagnostic test for presumptive tuberculosis (TB) patients in health facilities without the World Health Organization (WHO) recommended rapid diagnostic tools. In the Uganda TB laboratory network, the technique remains the only tool to monitor response to treatment among drug susceptible TB patients, with the country currently having over 1,600 microscopy TB testing units. It has been evidenced that acid-fast bacilli (AFB) microscopy’s yield highly depends on the staining technique and reading ability of the laboratory personnel. For the quality of TB testing in the country, the TB control program set up a Randomized Blinded Rechecking (RBRC) program in 2008 to monitor the testing performance of laboratories to continuously improve the reliability and efficiency of results. This is the first study to determine the effectiveness and impact of the RBRC program on the performance of the participating laboratories in Uganda. Methods This was a retrospective cross-sectional study based on a record review of the RBRC’s annual results compilations between January 2008 and December 2017. Results Between January 2008 and December 2017, a total of 265,523 smears were re-checked during the RBRC program. The number of enrolled laboratories in the RBRC program rose from 660 to 2008 to 1,406 in 2017. The RBRC program resulted in a statistically significant reduction in microscopy errors, with false positives decreasing from 12.8% to 2008 to 7.6% in 2017, false positive errors decreasing from 10 to 6.3%, false negative errors decreasing from 2.9 to 0.7%, quantification errors decreasing from 6.0 to 1.8%, and the overall sensitivity of smear microscopy compared to the controllers increased with statistical significance from 93 to 97%. Conclusion The study reveals an overall significant error reduction and an improved sensitivity of smear microscopy upon continuous implementation of the RBRC program in an AFB microscopy TB laboratory network. Implementation of a RBRC program is crucial and essential to maintaining a reliable TB laboratory service that can facilitate accurate diagnosis and offset the disadvantages of using smear microscopy.
Background Increased tuberculosis disease burden arises as a result of low treatment success rates stemming from the emergence of second-line drug resistance. We aimed at determining the usefulness of second-line drug (SLD) resistance markers as proxy indicators of time to sputum culture conversion; a renowned predictor of Tuberculosis treatment outcome, among SLD-resistant tuberculosis (TB) patients tested at the Uganda National TB Reference Laboratory (NTRL). Methods A cross-sectional study was conducted on 72 bacteriologically confirmed SLD resistant TB patients with datasets including culture conversion time and second line probe assay mutation profiles between 01/06/2017 and 31/12/2019. The data were then imported into STATA v15 for descriptive statistical analysis, Univariate cox proportional hazard model analysis and Kaplan-Meier survival curves at a 5% level of significance; p-value ≤0.05. Results Results indicate the median time was achieved at 3 (0–12) months across the studied patients. The rrs G1484T mutation associated with conferring drug resistance to injectable agents was observed to have the shortest median conversion time of 1.5 months, longest by the gryB E540D at 5 months. A single mutation in the gryA gene locus showed higher converted proportions 70.8% (58.9–81.0) than those that had two 8.3% (3.1–17.3) or three 2.7% (0.3–10.0) mutations. Conclusions The studied second-line drug resistance markers had no statistically significant association with the time to sputum culture conversion, although increased drug resistance levels reduced the converted proportions and stressed the need to utilize molecular diagnostics data and other crucial variables to better comprehend proxy indicators of SLD resistant tuberculosis management.
Background Proficiency testing (PT) has been hard to set up due to cost limitations and technical capacity. Conventional Xpert MTB/RIF PT programs use liquid and culture spots which require stringent storage and transportation conditions with cross-contamination chances prevalent. These setbacks prompted the use of dried tube specimens (DTS) for Ultra assay PT. For continuity of PT provision, stability of DTS and compatibility with testing protocols when kept for a long period needs to be established. Methods DTS were prepared from known isolates inactivated using a hot air oven at 85°C. 100μl of bacterial suspensions were aliquoted and dried inside a Biosafety cabinet. Panel validation was done to establish the baseline Deoxyribonucleic acid (DNA) concentration in terms of cycle threshold (Ct) value. DTS aliquots were shipped to participants to test and report within six weeks. The remaining DTS were kept at 2–8°C and room temperature for one year with testing at six months. Twenty (20) DTS samples per set remaining at one year were heated at 55°C for two weeks before testing. The means of the different samples were compared to validation data using paired t-tests. Boxplots were designed to visualize the differences in the medians of the DTS. Results Overall mean Ct value increased by 4.4 from the validation to testing after one year at the different storage conditions. Samples heated at 55°C showed a 6.4 Ct difference from validation data. Testing done at six months on 2–8°C stored items showed no statistical difference. At all the remaining testing times and conditions, P-values were less than 0.008 although the absolute mean Ct when compared showed slight increments and accommodated differences for the detection of MTB and rifampicin resistance. Median values for samples stored at 2–8°C were lower compared to those at room temperature. Conclusion DTS stored at 2–8°C remain more stable for one year compared to higher temperatures and can be consistently used as PT materials in more than one PT round for biannual PT providers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.