Last data update: May 28, 2024. (Total: 46864 publications since 2009)
Records 1-4 (of 4 Records) |
Query Trace: Skaggs BA[original query] |
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First round of external quality assessment scheme for SARS-CoV-2 laboratories during the COVID-19 pandemic in Thailand
Saeng-Aroon S , Changsom D , Boonmuang R , Waicharoen S , Buayai K , Okada P , Uppapong B , Chittaganpitch M , Soisangwan P , Praphasiri P , Skaggs BA . Health Secur 2023 21 (3) 183-192 The emergence of SARS-CoV-2 necessitated the rapid deployment of tests to diagnose COVID-19. To monitor the accuracy of testing across the COVID-19 laboratory network in Thailand, the Department of Medical Sciences under the Ministry of Public Health launched a national external quality assessment (EQA) scheme using samples containing inactivated SARS-CoV-2 culture supernatant from a predominant strain in the early phase of the Thailand outbreak. All 197 laboratories in the network participated; 93% (n=183) of which reported correct results for all 6 EQA samples. Ten laboratories reported false-negative results, mostly for samples with low viral concentrations, and 5 laboratories reported false-positive results (1 laboratory reported false positives and false negatives). An intralaboratory investigation of 14 laboratories reporting incorrect results revealed 2 main causes of error: (1) RNA contamination of the rRT-PCR reaction and (2) poor-quality RNA extraction. Specific reagent combinations were significantly associated with false-negative reports. Thailand's approach to national EQA for SARS-CoV-2 can serve as a roadmap for other countries interested in implementing a national EQA program to ensure laboratories provide accurate testing results, which is crucial in diagnosis, prevention, and control strategies. A national EQA program can be less costly and thus more sustainable than commercial EQA programs. National EQA is recommended to detect and correct testing errors and provide postmarket surveillance for diagnostic test performance. |
Are post-Ebola reconstruction efforts neglecting public health laboratory systems?
Nkengasong JN , Skaggs BA . Lancet Glob Health 2015 3 (11) e678 David Evans and colleagues (August, 2015)1 modelled how the loss of health-care workers to Ebola virus disease (EVD) might have affected infant, under 5, and maternal mortality in Guinea, Liberia, and Sierra Leone. Unfortunately, laboratory workers were not included in the health-care worker definition used in their model. Laboratory workers are a central part of an effective health system. In the same issue, Ranu Dhillon and Robert Yates2 propose five priorities for Ebola-affected countries. These also did not include the need for an effective public health laboratory system. | The Ebola epidemic repeatedly showed that delays in laboratory confirmation impeded control and prevention efforts. Without effective public health laboratory systems, public health responses will be delayed and global health security will be threatened. Strengthening public health laboratory systems should be a priority in the reconstruction and recovery efforts. |
Biofilm production and evaluation of antifungal susceptibility amongst clinical Candida spp. isolates, including strains of the Candida parapsilosis complex
Melo AS , Bizerra FC , Freymuller E , Arthington-Skaggs BA , Colombo AL . Med Mycol 2011 49 (3) 253-62 Candida cells can form biofilms that frequently are sources of infections and are less susceptible to antifungal drugs. Some authors have reported that Candida orthopsilosis and Candida metapsilosis isolates are not able to produce biofilms in vitro and there are no studies available on biofilm susceptibility for these species to antifungals. The aims of this study were to (i) quantify Candida spp. biofilms in vitro, and (ii) test the in vitro susceptibilities of Candida spp. biofilms to fluconazole (FLC) and amphotericin B (AMB). Isolates studied included four Candida albicans, six C. tropicalis, seven C. parapsilosis, eight C. orthopsilosis, and five C. metapsilosis. We compared two different methods to evaluate biofilm production, i.e., crystal violet (CV) staining and XTT-reduction assays (XTT). Scanning electron microscopy (SEM) was used to observe high, medium and low biofilm producing isolates screened by these two methods. To determine the minimum biofilm eradication concentration (MBEC) for FLC and AMB, XTT-reduction assay was used to measure cell metabolic activity. Biofilm quantification by CV and XTT showed that C. tropicalis isolates were the highest biofilm producer, followed by C. albicans, C. parapsilosis, C. orthopsilosis and C. metapsilosis. Examination of SEM images revealed that the extent of biofilms formed by high, medium, and low producers was highly correlated to the results generated by CV assay. Biofilm of all the isolates evaluated were resistant to FLC (MBEC(80) ≥ 256 ug/ml) but, in general, susceptible to AMB, except for six C. parapsilosis strains (MBEC(80) ≥ 8 ug/ml). |
Effect of serum and surface characteristics on Candida albicans biofilm formation
Frade JP , Arthington-Skaggs BA . Mycoses 2010 54 (4) e154-62 Candida spp. biofilms can be established on a wide range of materials, including implanted medical devices, and can display a resistant phenotype to antifungal drugs. Several factors, including host and surface properties, may influence the establishment and the development of Candida albicans biofilms on biotic and abiotic surfaces. We therefore selected a collection of C. albicans clinical isolates to evaluate the effect of surface and serum on biofilm attachment and development. Disc coupons from the CDC biofilm reactor were used in a well plate assay to study biofilm production on six different surfaces with or without the addition of serum: polycarbonate, polystyrene, stainless steel, Teflon, polyvinyl chloride or hydroxyapatite. Our results showed that serum increases in vitro C. albicans biofilm formation on a wide range of distinct surfaces including metallic and non-metallic materials, and that roughness and hydrophobicity can modulate C. albicans biofilm formation. These findings were also confirmed by scanning electron microscopy and it revealed the deposition of extracellular material on hyphae attached to a solid surface. Interestingly, adhesion can be significantly increased in the early stages of colonisation when serum is provided as a conditioning film in a surface-dependent manner. |
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