Microbial silver resistance mechanisms: recent developments.

In this mini-review, after a brief introduction into the widespread antimicrobial use of silver ions and nanoparticles against bacteria, fungi and viruses, the toxicity of silver compounds and the molecular mechanisms of microbial silver resistance are discussed, including recent studies on bacteria and fungi. The similarities and differences between silver ions and silver nanoparticles as antimicrobial agents are also mentioned. Regarding bacterial ionic silver resistance, the roles of the sil operon, silver cation efflux proteins, and copper-silver efflux systems are explained. The importance of bacterially produced exopolysaccharides as a physiological (biofilm) defense mechanism against silver nanoparticles is also emphasized. Regarding fungal silver resistance, the roles of metallothioneins, copper-transporting P-type ATPases and cell wall are discussed. Recent evolutionary engineering (adaptive laboratory evolution) studies are also discussed which revealed that silver resistance can evolve rapidly in bacteria and fungi. The cross-resistance observed between silver resistance and resistance to other heavy metals and antibiotics in bacteria and fungi is also explained as a clinically and environmentally important issue. The use of silver against bacterial and fungal biofilm formation is also discussed. Finally, the antiviral effects of silver and the use of silver nanoparticles against SARS-CoV-2 and other viruses are mentioned. To conclude, silver compounds are becoming increasingly important as antimicrobial agents, and their widespread use necessitates detailed understanding of microbial silver response and resistance mechanisms, as well as the ecological effects of silver compounds. Figure created with BioRender.com.

Analysis of university student responses to the pandemic in a formal microbiology assessment.

During the coronavirus pandemic, second-year students on the B.Sc. molecular biology and genetics degree at Istanbul Technical University sat an open-ended online exam for a microbiology course in which one of the compulsory questions asked how the course had helped them during the first phase of the pandemic (April-July 2020). Fifty of 69 students gave consent for their (anonymous) responses to be analysed in order to discern any key ways in which their knowledge had been applied. The aim of the study was to investigate whether taking an advanced microbiology course increases understanding of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic and has a positive impact on student behaviours with respect to public health practices. Findings were divided into four major themes: course content (information), application of course content to behavioural change (practice), professionalism and their 'audience' whilst at home in lockdown (family and friends). Social distancing, wearing face masks, and hand and surface hygiene were described as important behaviours, with this practice informed by their basic microbiology knowledge. This paper describes a scenario where rote assessment can be used to assess wider scientific literacy with respect to application in society, providing students with an opportunity to incorporate and apply their learning into real-life situations, whilst tutors can assess constructivist learning, conceptual understanding and impact on student behaviour.