Bacterial infection of bladder (cystitis). Colour Scanning Electron Micrograph (SEM) of cells of the human bladder infected with bacteria. Rod-shaped Escherichia coli bacteria (yellow) are seen on bladder epithelial cells (blue). This is a chronic infection causing some cells (purple) to swell and reduce in diameter, develop a rough surface and become detached. Secreted mucus filaments appear orange. Bladder infection or cystitis is commonly due to E.coli bacteria, causing pain in passing urine and bladder inflammation. It affects more women because the urethra is shorter and easily infected. Magnification: x290 at 6x7cm size. x415 at 4x5"~LANDSCAPE"