MICROBIOLOGY
Shiga toxin-producing Escherichia coli (STEC): a diagnostic conundrum
Following on from his recent article on Escherichia coli, Dr Neil Bentley looks at Shiga toxin-producing E. coli (STEC), considering the multiple challenges posed by this pathogen and recent diagnostic advances.
Shiga toxin-producing Escherichia coli (STEC) represents one of the most critical foodborne pathogens worldwide. Responsible for a clinical spectrum ranging from self-limited diarrhoea to life- threatening systemic complications such as haemolytic uraemic syndrome (HUS). STEC infections arise from a complex interaction between bacterial virulence, host susceptibility, and environmental factors. Notably, STEC has an extremely low infectious dose, with less than 100 bacteria capable of eliciting severe disease.1
In an era of globalisation that
interconnects food supply chains, coupled with climate change which reshapes pathogen ecology; our understanding and mitigation of STEC risks must be both multifaceted and dynamic. Here, we review the historical evolution and scientific advances in STEC research, including transmission dynamics, molecular pathogenicity, diagnostic challenges, and the broader socio- economic and public health implications of STEC outbreaks.
Historical overview of STEC
n Discovery of Escherichia coli and early observations
In 1885, Theodor Escherich isolated E. coli from neonatal intestinal tracts, establishing its status as a commensal inhabitant of the gastrointestinal system.2 Over time, scientists identified that while
most E. coli strains are commensals, a subset could cause disease. An example is the identification of enteropathogenic E. coli (EPEC) in the 1940s, which identified that certain strains were able to cause diarrhoea and dysentery,3
the underlying pathogenic potential of some E. coli pathotypes.
n Discovery of Shiga toxin The groundbreaking work of Kiyoshi Shiga between 1897 and 1898 led to the identification of Shigella dysenteriae and its potent toxin responsible for causing severe dysentery.4
the discovery that certain E. coli strains produced toxins immunologically and functionally analogous to Shiga toxin gave rise to the classification of STEC.5
n STEC emerges as a major foodborne pathogen
indicating
By the early 1980s, scientists began to systematically screen E. coli strains for toxin production, leading to the identification of STEC strains that produced Shiga toxins. This distinction
Subsequently,
A three-dimensional illustration of Escherichia coli bacteria.
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