Bacteria from a train door handle, coloured scanning electron micrograph (SEM). In studies, seats and handles on most trains harbour infectious bacteria that can survive at least one antibiotic. Some bacteria, such as certain strains of E.coli and MRSA, can cause life-threatening illnesses, although most of the bacteria detected were harmless. DNA (deoxyribonucleic acid) analysis identified that 32 per cent of bacteria were associated with the gastrointestinal tract and 29 per cent with the skin. Another 20 per cent was associated with the genital area, largely as a result of poor hygiene. Magnification: X 6000 when printed at 10 centimetres wide.