Escherichia coli O157:H7 str. Sakai

Escherichia coli O157:H7 str. Sakai is a gram-negative, rod-shaped bacterium that falls within the mesophilic temperature preference category, thriving optimally between 20–45°C. This strain is classified as a heterotroph, meaning it derives its energy from organic compounds, and it is considered a facultative anaerobe, capable of surviving in both aerobic and anaerobic conditions. As a member of the normal gut flora in many animals, E. coli can inhabit various body sites, including the intestines of humans and other warm-blooded organisms, where it plays a significant role in digestion. The gram-negative nature of E. coli O157:H7 str. Sakai indicates that it has a thin peptidoglycan layer surrounded by an outer membrane containing lipopolysaccharides, contributing to its pathogenicity. The rod-shaped (bacillus) morphology facilitates its motility and colonization in the gastrointestinal tract. As a mesophilic organism, it maintains robust metabolic activities within the temperature range found in the human body, making it well-adapted for survival. E. coli O157:H7 str. Sakai is known for its association with severe foodborne illness, including hemolytic uremic syndrome (HUS). It produces Shiga toxin, which can cause serious complications, primarily affecting the kidneys. This strain of E. coli is often linked to contaminated food (especially undercooked beef) and water sources. The presence of E. coli O157:H7 in food safety testing is a critical concern given its potential for outbreaks. Furthermore, genetic studies have revealed insights into its virulence factors and mechanisms of antibiotic resistance, highlighting its significance in public health and microbiological research.