The chemical characterization of the substance responsible for the phenomenon of “transformation” of pneumococci was presented in the now famous 1944 paper by Avery, MacLeod, and McCarty. Reception of this work was mixed. Although interpreting their results as evidence that deoxyribonucleic acid (DNA) is the molecule responsible for genetic changes was, at the time, controversial, this paper has been retrospectively celebrated as providing such evidence. The mixed and changing assessment of the evidence presented in the paper was due to (...) the work’s interpretive flexibility – the evidence was interpreted in various ways, and such interpretations were justified given the neophytic state of molecular biology and methodological limitations of Avery’s transformation studies. I argue that the changing context in which the evidence presented by Avery’s group was interpreted partly explains the vicissitudes of the assessments of the evidence. Two less compelling explanations of the reception are a myth-making account and an appeal to the wartime historical context of its publication. (shrink)

ArgumentThis article examines how antimicrobial resistance (AMR) came to be constituted as a matter of public concern in Sweden in conjunction with the development of an inter-professional organization called Strama, founded to promote rational prescription of antibiotics. An outbreak of penicillin-resistant pneumococci in the mid-1990s was crucial for this development, because it brought attention to AMR as an urgent public threat. This outbreak fuelled the constitution of AMR as caused by consumption of antibiotics and as a matter of disease (...) control. As a consequence, Strama was able to mobilize the Swedish health officers responsible for disease control. The outbreak is conceptualized as a “transformative event” – an event that makes an issue and its associated risks concrete and urgent. Transformative events play the crucial role of expediting the transformation of issues into matters of public concern. (shrink)

Transport of DNA across bacterial membranes involves complex DNA uptake systems. In Gram‐positive bacteria, the DNA uptake machinery shares fundamental similarities with type IV pili and type II secretion systems. Although dedicated pilus structures, such as type IV pili in Gram‐negative bacteria, are necessary for efficient DNA uptake, the role of similar structures in Gram‐positive bacteria is just beginning to emerge. Recently two essentially very different pilus structures composed of the same major pilin protein ComGC were proposed to be involved (...) in transformation of the Gram‐positive bacterium Streptococcus pneumoniae – one is a long, thin, type IV pilus‐like fiber with DNA binding capacity and the other one is a pilus structure that was thicker, much shorter and not able to bind DNA. Here we discuss how competence induced pili, either by pilus retraction or by a transient pilus‐related opening in the cell wall, may mediate DNA uptake in S. pneumoniae. (shrink)