Evaluation of the modified colorimetric resazurin microtiter plate-based antibacterial assay for rapid and reliable tuberculosis drug susceptibility testing

Background: The resazurin microtiter assay (classic REMA), a colorimetric liquid culture-based drug susceptibility assay for Mycobacterium tuberculosis (MTB), has been endorsed by the World Health Organization. The assay requires 8-16 days to obtain results, delaying management of drug resistant tuberculosis patients. A modified REMA which allows results in as little as 24 hours for bacterial strains, has been developed and validated using Staphylococcus aureus, but has not yet been evaluated for MTB. Therefore we assessed the performance of the modified REMA for rifampicin (RIF) and isoniazid (INH) susceptibility, using the classic REMA as the reference standard. We also compared simplicity (from the technicians’ point of view), time taken to obtain results (rank-sum testing), specificity and Kappa statistics of the two methods. Results: The modified REMA, which is a one-step procedure, was found to be simpler to perform and results were obtained in a significantly shorter time (5 versus 9 days, p < 0.0001) compared to the classic REMA due to addition of indicator and strain at the same time. The specificity of the modified REMA was low {46.8% (35.5% - 58.4%) for RIF and 13.9% (7.2% - 23.5%) for INH}. Kappa statistics were 16.0% for RIF and 2.0% for INH. Low specificity and kappa statistics are due to indicator reduction by the strains before complete drug activity. Conclusion: Although modified REMA is faster and simpler compared to classic REMA, it is not reliable for MTB drug susceptibility testing

Evaluation of the SD BIOLINE HIV/syphilis Duo assay at a rural health center in Southwestern Uganda

Background: Point-of-care tests have the capacity to improve healthcare delivery by reducing costs and delay associated with care. A novel point-of-care immunochromatographic test for dual diagnosis of both HIV and syphilis by detecting IgG, IgM and IgA antibodies to HIV, and specific and recombinant Treponema pallidum antigens has recently been developed, but has not been evaluated in rural field settings. We evaluated the performance of the SD Bioline Syphilis/HIV Duo (Duo) assay at a healthcare center in rural Uganda. Methods: A convenience sample of pregnant women attending Kinoni Health Centre IV from March to May, 2013 was enrolled. Venous blood was collected and centrifuged for plasma isolation. Samples were tested with the Duo assay and compared with the Treponema pallidum hemaglutination assay and paired HIV rapid antibody tests as the reference standards. The ease of use and time required for the Duo assay were also assessed by laboratory technicians. Results: Two hundred twenty women were enrolled with a mean age of 25.00 years (SD 5.41). The sensitivity and specificity of the Duo assay were 100% (95% CI 79.0 – 100%) and 100% (95% CI 97.6 – 100.0) respectively, for syphilis, and, 100% (75.9 – 100%) and 99.5% (96.8 – 99.9%) respectively, for HIV. The duo kit was found to be faster and easier to use than the current HIV and syphilis testing techniques. Conclusion: The sensitivity and specificity of the SD Bioline HIV/Syphilis Duo test were excellent in a field setting in Uganda. The Duo assay should be further evaluated in alternate populations and with point-of-care specimens (e.g. whole blood from finger stick specimens), but shows promise as a tool for improved HIV and syphilis surveillance, diagnosis, and treatment in field settings

Establishing Ebola Virus Disease (EVD) diagnostics using GeneXpert technology at a mobile laboratory in Liberia: Impact on outbreak response, case management and laboratory systems strengthening.

The 2014-16 Ebola Virus Disease (EVD) outbreak in West Africa highlighted the necessity for readily available, accurate and rapid diagnostics. The magnitude of the outbreak and the re-emergence of clusters of EVD cases following the declaration of interrupted transmission in Liberia, reinforced the need for sustained diagnostics to support surveillance and emergency preparedness. We describe implementation of the Xpert Ebola Assay, a rapid molecular diagnostic test run on the GeneXpert platform, at a mobile laboratory in Liberia and the subsequent impact on EVD outbreak response, case management and laboratory system strengthening. During the period of operation, site coordination, management and operational capacity was supported through a successful collaboration between Ministry of Health (MoH), World Health Organization (WHO) and international partners. A team of Liberian laboratory technicians were trained to conduct EVD diagnostics and the laboratory had capacity to test 64-100 blood specimens per day. Establishment of the laboratory significantly increased the daily testing capacity for EVD in Liberia, from 180 to 250 specimens at a time when the effectiveness of the surveillance system was threatened by insufficient diagnostic capacity. During the 18 months of operation, the laboratory tested a total of 9,063 blood specimens, including 21 EVD positives from six confirmed cases during two outbreaks. Following clearance of the significant backlog of untested EVD specimens in November 2015, a new cluster of EVD cases was detected at the laboratory. Collaboration between surveillance and laboratory coordination teams during this and a later outbreak in March 2016, facilitated timely and targeted response interventions. Specimens taken from cases during both outbreaks were analysed at the laboratory with results informing clinical management of patients and discharge decisions. The GeneXpert platform is easy to use, has relatively low running costs and can be integrated into other national diagnostic algorithms. The technology has on average a 2-hour sample-to-result time and allows for single specimen testing to overcome potential delays of batching. This model of a mobile laboratory equipped with Xpert Ebola test, staffed by local laboratory technicians, could serve to strengthen outbreak preparedness and response for future outbreaks of EVD in Liberia and the region

Assessment of three medical and research laboratories using WHO AFRO_SLIPTA Quality Standards in Southwestern Uganda: a long way to go

Introduction: While the laboratory represents more than 70% of clinical diagnosis and patient management, access to reliable and quality laboratory diagnostics in sub-Saharan Africa remains a challenge. To gain knowledge and suggest evidence based interventions towards laboratory improvement in Southwestern Uganda, we assessed the baseline laboratory quality standards in three medical and research laboratories in Southwestern Uganda. Methods: We conducted a cross sectional survey from October, 2013 to April, 2014. Selected laboratories, including one private research, one private for profit and one public laboratory, were assessed using the WHO AFRO_SLIPTA checklist and baseline scores were determined. Results: The three laboratories assessed met basic facility requirements, had trained personnel, and safety measures in place. Sample reception was properly designed and executed with a well designated chain of custody. All laboratories had sufficient equipment for the nature of work they were involved in. However, we found that standard operating procedures were incomplete in all three laboratories, lack of quality audit schemes by two laboratories and only one laboratory enrolled into external quality assurance schemes. The SLIPTA scores were one star for the research laboratory and no star for both the public and private-for-profit laboratories. Conclusion: While most of the laboratory systems were in place, the low scores obtained by the assessed laboratories reflect the need for improvement to reach standards of quality assured diagnostics in the region. Therefore, routine mentorship and regional supportive supervision are necessary to increase the quality of laboratory services

Predictive modeling targets thymidylate synthase ThyX in Mycobacterium tuberculosis

International audienceThere is an urgent need to identify new treatments for tuberculosis (TB), a major infectious disease caused by Mycobacterium tuberculosis (Mtb), which results in 1.5 million deaths each year. We have targeted two essential enzymes in this organism that are promising for antibacterial therapy and reported to be inhibited by naphthoquinones. ThyX is an essential thymidylate synthase that is mechanistically and structurally unrelated to the human enzyme. DNA gyrase is a DNA topoisomerase present in bacteria and plants but not animals. The current study set out to understand the structure-activity relationships of these targets in Mtb using a combination of cheminformatics and in vitro screening. Here, we report the identification of new Mtb ThyX inhibitors, 2-chloro-3-(4-methanesulfonylpiperazin-1-yl)-1,4-dihydronaphthalene-1,4-dione) and idebenone, which show modest whole-cell activity and appear to act, at least in part, by targeting ThyX in Mtb

Timeline of key events in establishing and running the ELWA-III mobile EVD testing laboratory—September 2015 to March 2017.

<p>Timeline of key events in establishing and running the ELWA-III mobile EVD testing laboratory—September 2015 to March 2017.</p

Representation of the layout of the ELWA-III mobile Ebola testing laboratory, at the ELWA Ebola treatment unit, Monrovia.

<p>Representation of the layout of the ELWA-III mobile Ebola testing laboratory, at the ELWA Ebola treatment unit, Monrovia.</p

Antibiotic use among hospitalised patients in Sierra Leone: a national point prevalence survey using the WHO survey methodology

Objective Inappropriate use of antibiotics is a major driver of antibiotic resistance. A few studies conducted in Africa have documented that about half of hospitalised patients who receive antibiotics should not have received them. A few hospital-based studies that have been conducted in Sierra Leone have documented a high usage of antibiotics in hospitals. Therefore, we conducted a nationwide point prevalence survey on antibiotic use among hospitalised patients in Sierra Leone.Design We conducted a hospital-based, cross-sectional survey on the use of antibiotics using the WHO point prevalence survey methodology.Setting The study was conducted in 26 public and private hospitals that are providing inpatient healthcare services.Participants All patients admitted to paediatric and adult inpatient wards before or at 08:00 on the survey date were enrolled.Outcome measures Prevalence of antibiotic use, antibiotics Access, Watch and Reserve (AWaRe) categorisation, indication for antibiotic use prevalence and proportion of bacteria culture done.Results Of the 1198 patient records reviewed, 883 (73.7%, 95% CI 71.1% to 76.2%) were on antibiotics. Antibiotic use was highest in the paediatric wards (306, 85.7%), followed by medical wards (158, 71.2%), surgical wards (146, 69.5%), mixed wards (97, 68.8%) and lowest in the obstetrics and gynaecology wards (176, 65.7%). The most widely prescribed antibiotics were metronidazole (404, 22.2%), ceftriaxone (373, 20.5%), ampicillin (337, 18.5%), gentamicin (221, 12.1%) and amoxicillin (90, 5.0%). Blood culture was only done for one patient and antibiotic treatments were given empirically. The most common indication for antibiotic use was community-acquired infection (484, 51.9%) followed by surgical prophylaxis (222, 23.8%).Conclusion There was high usage of antibiotics in hospitals in Sierra Leone as the majority of patients admitted received an antibiotic. This has the potential to increase the burden of antibiotic resistance in the country. We, therefore, recommend the establishment of hospital antimicrobial stewardship programmes according to the WHO core components

Case definition of suspect case of viral haemorrhagic fever as defined in the Integrated Disease Surveillance and Response (IDSR) Guidelines for Liberia.

<p>Case definition of suspect case of viral haemorrhagic fever as defined in the Integrated Disease Surveillance and Response (IDSR) Guidelines for Liberia.</p