What causes Urinary Tract Infections in Children ?
Most UTIs are caused by bacteria that live in the bowel. The bacterium Escherichia coli (E. coli) causes the vast majority of UTIs. The urinary tract has several systems to prevent infection. The points where the ureters attach to the bladder act like one-way valves to prevent urine from backing up, or refluxing, toward the kidneys, and urination washes microbes out of the body. Immune defenses also prevent infection. But despite these safeguards, infections still occur. Certain bacteria have a strong ability to attach themselves to the lining of the urinary tract.
                
Children who often delay urination are more likely to develop UTIs. Regular urination helps keep the urinary tract sterile by flushing away bacteria. Holding in urine allows bacteria to grow. Producing too little urine because of inadequate fluid intake can also increase the risk of developing a UTI. Chronic constipationa condition in which a child has fewer than two bowel movements a weekcan add to the risk of developing a UTI. When the bowel is full of hard stool, it presses against the bladder and bladder neck, blocking the flow of urine and allowing bacteria to grow.
                
Some children develop UTIs because they are prone to such infections, just as other children are prone to getting coughs, colds, or ear infections.