A recent study of patients at 10 academic hospitals in the United States found that just over half care about what their doctors wear, most of them preferring the traditional white coat.

Some doctors prefer the white coat, too, viewing it as a defining symbol of the profession.

What many might not realize, though, is that health care workers’ attire — including that seemingly “clean” white coat that many prefer — can harbor dangerous bacteria and pathogens.

A systematic review of studies found that white coats are frequently contaminated with strains of harmful and sometimes drug-resistant bacteria associated with hospital-acquired infections. As many as 16 percent of white coats tested positive for MRSA, and up to 42 percent for the bacterial class Gram-negative rods.

Both types of bacteria can cause serious problems, including skin and bloodstream infections, sepsis and pneumonia.