Mycobacterium tuberculosis strains of the Beijing lineage are globally distributed and are associated with the massive spread of multidrug-resistant (MDR) tuberculosis in Eurasia. Here we reconstructed the biogeographical structure and evolutionary history of this lineage by genetic analysis of 4,987 isolates from 99 countries and whole-genome sequencing of 110 representative isolates. We show that this lineage initially originated in the Far East, from where it radiated worldwide in several waves. We detected successive increases in population size for this pathogen over the last 200 years, practically coinciding with the Industrial Revolution, the First World War and HIV epidemics. Two MDR clones of this lineage started to spread throughout central Asia and Russia concomitantly with the collapse of the public health system in the former Soviet Union. Mutations identified in genes putatively under positive selection and associated with virulence might have favored the expansion of the most successful branches of the lineage.

q Mycobacterium tuberculosis Beijing strains represent targets of special importance for molecular surveillance of tuberculosis (TB), especially because they are associated with spread of multidrug resistance in some world regions. Standard 24-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing lacks resolution power for accurately discriminating closely related clones that often compose Beijing strain populations. Therefore, we evaluated a set of 7 additional, hypervariable MIRU-VNTR loci for better resolution and tracing of such strains, using a collection of 535 Beijing isolates from six world regions where these strains are known to be prevalent. The typeability and interlaboratory reproducibility of these hypervariable loci were lower than those of the 24 standard loci. Three loci (2163a, 3155, and 3336) were excluded because of their redundant variability and/or more frequent noninterpretable results compared to the 4 other markers. The use of the remaining 4-locus set (1982, 3232, 3820, and 4120) increased the number of types by 52% (from 223 to 340) and reduced the clustering rate from 58.3 to 36.6%, when combined with the use of the standard 24-locus set. Known major clonal complexes/ 24-locus-based clusters were all subdivided, although the degree of subdivision varied depending on the complex. Only five single-locus variations were detected among the hypervariable loci of an additional panel of 92 isolates, representing 15 years of clonal spread of a single Beijing strain in a geographically restricted setting. On this calibrated basis, we propose this 4-locus set as a consensus for subtyping Beijing clonal complexes and clusters, after standard typing.

The incidence of carbapenemase genes did not vary significantly between the two study periods. There is a wide diversity of OXA genes in A. baumannii in Singapore. The most common carbapenemase gene found in our study was bla(OXA-23).

Introduction The COVID-19 pandemic resulted in the suspension of clinical training for undergraduate radiography students in Singapore. Coordinated preparation plans and strategies between the university and hospitals were needed to safely resume clinical placements within national and hospitals’ risk control measures against COVID-19 transmission. Methods Singapore Institute of Technology (SIT) and the Radiology Department of Singapore General Hospital (SGH) had collaborated to meet requirements for safe resumption of clinical placements. SIT prepared students by emphasising compliance to all risk measures, addressing concerns of risk transmission, meeting learning objectives, and reassessing infection control competencies. In tandem, SGH prepared an orientation programme and used technology for open communication among faculty, clinical educators and students which included monitoring of well-being and rapid dissemination of updates. Of note, SGH reorganised operating procedures and physical spaces to meet national standards of safe physical distancing, restricted movement between treatment areas and teams, and rosters to remain committed to the supervision and education of students. Results Clinical placements resumed 3 months following suspension. Clinical educators faced the challenge of the need for balance between increasing clinical load and student supervision. A solution was frequent engagement and support by faculty, with educators and students via video conferencing platforms. Students’ well-being was frequently checked. There was less variation in cases which simulation training made up for some of the learning objectives. Conclusion Adaptation and commitment to continue active and quality clinical education while ensuring students' safety were vital during a pandemic. Clinical training within stringent precautionary measures may shape the era of the new norm.