Your dirty laundry

Photo:  Mary Ann's Cupboards

There's a new paper in Infection Control and Hospital Epidemiology that includes a series of experiments designed to evaluate the effectiveness of laundering scrubs in your home washing machine. This is important since most healthcare workers who do not work in the operating room launder their own scrubs at home, and some hospitals even have OR staff wash their scrubs at home as a cost-savings measure. The major difference between home and hospital laundering is water temperature--hospital laundries typically use water temperatures of 160°F, whereas home washing machines are generally set to deliver water temperatures at 60-80°F (cold), 90-110°F (warm), or >130°F (hot).

Key findings were:

• Hot water (140°F) with or without detergent was highly effective in killing MRSA and Acinetobacter.
• Warm water (104°) with detergent was highly effective in killing MRSA and Acinetobacter. Without detergent, warm water was still highly effective against MRSA, but only moderately so against Acinetobacter.
• When clothes are washed with warm water but no detergent, they become contaminated with gram-negative organisms (Klebsiella, Enterobacter, Serratia) from the washing machine's biofilm, though washed clothes are largely free of gram-positive skin flora.
• When fabric swatches that were inoculated with Acinetobacter were ironed (on the iron's highest setting) with a contact time of at least 7 seconds, the organisms were killed.

So warm or hot water with detergent is your best bet (though I have to wonder who washes their clothes without detergent?). I do iron my scrubs, though many people don't, but I'm sure that my ironing contact time is less than 7 seconds, and some scrub fabrics can't tolerate the iron's highest setting.