Threat of Cronobacter in infants? Boil water for formula.

My son is 7 weeks old and exclusively formula fed. At the hospital, we were cautioned to always boil water when making powdered formula. As in, we were directed to make the formula with very very hot water to kill germs. Based on this page from the CDC, it appears the purpose is to prevent Cronobacter.

Realistically, what is the prevalence of Cronobacter in formula? And how long am I going to have to boil water for formula?