I did not say "secondary infection".
I said "secondary complication".
By definition, an "iatrogenic induced sepsis" is a complication of whatever intervention (central line, Foley catheter, wound contamination, etc.) gave rise to the sepsis.
Sepsis is not a primary disease that you simply "catch" out of the clear blue sky.
For example, Stonewall Jackson was shot in the arm. The arm had to be amputated. He then developed pneumonia, possibly from aspiration during surgery. He then developed sepsis and died.
Stonewall Jackson did not die because he "caught" sepsis. He died because he "caught" a .577 caliber Enfield round to his arm.
Anything that can get bacteria into the bloodstream from a gunshot wound, to pneumonia, to childbirth, to a central venous line inserted during hospitalization to cutting your hand while gardening can cause sepsis.
The author refers to sepsis as "a common bloodstream infection" as if it were a unique infectious disease such as AIDS or TB.
The lay reader is left to wonder and fear if he might "catch" sepsis if he goes to visit Aunt Martha at the hospital.