Dragos Zaharia

MicroDSC study of Staphylococcus epidermidis growth

BackgroundA microcalorimetric study was carried out using a Staphylococcus epidermidis population to determine the reproducibility of bacterial growth and the variability of the results within certain experimental parameters (temperature, bacterial concentration, sample thermal history). Reproducibility tests were performed as series of experiments within the same conditions using either freshly prepared populations or samples kept in cold storage. In both cases, the samples were obtained by serial dilution from a concentrated TSB bacterial inoculum incubated overnight.ResultsThe results show that experiments are fairly reproducible and that specimens can be preserved at low temperatures (1 - 2°C) at least 4 days. The thermal signal variations at different temperatures and initial bacterial concentrations obey a set of rules that we identified.ConclusionOur study adds to the accumulating data and confirms available results of isothermal microcalorimetry applications in microbiology and can be used to standardize this method for either research or clinical setting.

The TB Portals: an Open-Access, Web-Based Platform for Global Drug-Resistant-Tuberculosis Data Sharing and Analysis

ABSTRACT The TB Portals program is an international consortium of physicians, radiologists, and microbiologists from countries with a heavy burden of drug-resistant tuberculosis working with data scientists and information technology professionals. Together, we have built the TB Portals, a repository of socioeconomic/geographic, clinical, laboratory, radiological, and genomic data from patient cases of drug-resistant tuberculosis backed by shareable, physical samples. Currently, there are 1,299 total cases from five country sites (Azerbaijan, Belarus, Moldova, Georgia, and Romania), 976 (75.1%) of which are multidrug or extensively drug resistant and 38.2%, 51.9%, and 36.3% of which contain X-ray, computed tomography (CT) scan, and genomic data, respectively. The top Mycobacterium tuberculosis lineages represented among collected samples are Beijing, T1, and H3, and single nucleotide polymorphisms (SNPs) that confer resistance to isoniazid, rifampin, ofloxacin, and moxifloxacin occur the most frequently. These data and samples have promoted drug discovery efforts and research into genomics and quantitative image analysis to improve diagnostics while also serving as a valuable resource for researchers and clinical providers. The TB Portals database and associated projects are continually growing, and we invite new partners and collaborations to our initiative. The TB Portals data and their associated analytical and statistical tools are freely available at https://tbportals.niaid.nih.gov/ .