Two critically ill infants who died earlier this month in the Neonatal Intensive Care Unit of Miami Children's Hospital succumbed to infections from an extremely common bacteria found on many humans, health administrators said. The two infants were infected with strains of the Pseudomonas bacteria, which is widespread throughout nature, found in water, soil, plants, and animals. The three children were infected by three different strains of the bacteria, said a senior physician with the Miami-Dade Health Department.