Holy sheet! Laundering hospital linen fails to remove all C. diff

Only around 35% of the spores are removed in the process

It may be worth advising patients who are heading to hospital to bring their own sheets, based on new, stomach-churning research.

Current laundering practices are not enough to remove all traces of Clostridium difficile, which means patients may be contracting infectious diarrhoea from hospital linens, according to UK researchers.

Washing, drying and finishing naturally contaminated sheets to National Health Service standards in a commercial laundry only removes about 35% of C. difficile spores, they report in Infection Control and Hospital Epidemiology.

“This study provides the first estimate of the level of C. difficile spore contamination on a naturally contaminated sheet, which was surprisingly low considering the published estimate of spore shedding in [C. difficile infection] patients.

“The level of C. difficile spores present on the sheets before washing (51cfu/25cm2) was comparable to that found after washing (33cfu/25cm2)," the researchers write.

A second test — involving inoculated cotton sheets laundered in a simulated washer extractor, with and without detergent — also failed the microbiological standard of removing all pathogenic bacteria.

Even after being pummelled with industrial bleach detergent, sodium hypochlorite and peracetic acid, two strains of C. difficile remained.

Worse still, sterile fabric swatches placed in with the bacteria-laden sheets were contaminated with C. difficile spores during the laundering process.

This suggested that processing infected linen in commercial washer extractors could disseminate low levels of C. difficile spores and contribute to sporadic outbreaks of infection, the researchers said.

All the test washes used in the study reached 75°C and were held at more than 71°C for more than three minutes.

The same detergent was used in the commercial laundry and simulated washes.

The presence of C .difficile spores after laundering was confirmed by scanning electron microscopy.

Despite failing to completely eradicate the bacteria, adding detergent to the wash was found to be an important factor in significantly reducing the number of spores in the simulated washer extractor test.

Cross-contamination of sterile sheets laundered in the simulated washer extractor was much higher when detergent was not used.

However, in the commercial laundry test, adding detergent failed to make a significant difference to spore numbers, a surprising finding given the sheets were exposed to more high-temperature cycles than those in the simulated washes, the researchers wrote.

“The low levels of C. difficile spores surviving on laundered bed sheets may pose a transmission risk via hands touching the linen,” they said.

"The findings of this study may explain some sporadic outbreaks of C. difficile infections in hospitals from unknown sources; however, further research is required in order to establish the true burden of hospital bedsheets in such outbreaks," adds lead author Dr Katie Laird Head (PhD) of the Infectious Disease Research Group at De Montfort University’s School of Pharmacy in Leicester.

"Future research will assess the parameters required to remove C. difficile spores from textiles during the laundry process."

More information: Infection Control and Hospital Epidemiology 2018