E. coli causes: September 2011

Ans. D: All of the above Four main types of clinical syndromes are caused by E. coli: Urinary tract infection, diarrhea, pyogenic infections and septicemia Escherichia coli E. coli and related bacteria constitute about 0.1% of gut flora and fecal-oral transmission is the major route through which pathogenic strains of the bacterium cause disease. Cells are able to survive outside the body for a limited amount of time, which makes them ideal indicator organisms to test environmental samples for fecal contamination. E. coli is Gram-negative, facultative anaerobic and non-sporulating. Cells are typically rod-shaped, and are about 2.0 micrometers (pm) long and 0.5 pm in diameter, with a cell volume of 0.6 - 0.7 (pm)3. E. coli uses mixed-acid fermentation in anaerobic conditions, producing lactate, succinate, ethanol, acetate and carbon dioxide. Optimal growth of E. coli occurs at 37degC (98.6degF) Strains that possess flagella can swim and are motile. The flagella have a peritrichous arrangement. E. coli and related bacteria possess the ability to transfer DNA bacterial conjugation, transduction or transformation, which allows genetic material to spread horizontally through an existing population. This process led to the spread of the gene encoding shiga toxin from Shigella to E. coli 0157:H7, carried by a bacteriophage Virulent strains of E. coli can cause gastroenteritis, urinary tract infections, and neonatal meningitis. In rarer cases, virulent strains are also responsible for haemolytic-uremic syndrome, peritonitis, mastitis, septicaemia and Gram-negative pneumonia.