The following four types of infections account for more than 80% of all health care-associated infections:

• urinary tract infections usually associated with catheters:

     - catheter-associated urinary tract infections are the most frequent, accounting for about 35% health care-associated infections;

• surgical infections:

     - these are second in frequency, about 20%;

• bloodstream infections associated with the use of an intravascular device:

     - about 15%;

• pneumonia associated with ventilators:

     - about 15%.