Some cases of articificial nails have been linked to adverse outcomes:
16 babies died in a neonatal ICU in Oklahoma City from nosocomial infection (pseudomonas) that was traced to two nurses with articial nails.
An outbreak of postop infection (serratia) in cardiovascular patients was traced to an OR nurse with artificial nails.
A deep wound infection (candida) of a post-laminectomy patient was traced to an operating room technician with articifial nails.
So as you can see, several different organisms may be involved making it difficult to identify a common cause of infection.
Some reasons that artificial nails can cause and spread infection :
Most handborne microbes concentrate in the "subungual zone" (the space between the fingertip and the nail), and long nails of any material (artificial or real) make it harder to clean this area.
An artificial nail can separate from the natural nail base if bumped or snagged, leaving an opening that harbor dirt and germs (Gram-negative bacteria or fungi).
Long nails are more likely to tear or create microtears in latex gloves, bringing nurses into contact with skin or fluids.
Not just artificial nails but also jewelry can also harbor bacteria and infection. Several studies have shown that skin underneath rings is more heavily colonized with bacteria than skin on exposed fingers. Furthermore, it was found that nurses can carry these microorganisms for months underneath their rings!
Note: In the past the recommended standard for hand hygiene was vigorous handwashing with soap and water for 30-60 seconds. The CDC has revised the standard and now recommends using alcohol based handrub if the skin is not visibly soiled. For visibly soiled skin, handwashing with soap and water and friction is still recommended.
Hope this helps! We all can use a refresher couse some time!