• The efficacy of laundering and processing is particularly important relating to the persistence of Clostridioides difficile spores , which exhibit thermotolerance and resistance to disinfection and have been demonstrated in studies to survive industrial laundering .
hospitalized patients being immunocompromised or possessing underlying co-morbidities . Large epidemiological or intervention studies are required to provide more robust evidence of any direct link between contaminated textiles and HAIs to conclude the scale of any potential transmission through this route ( Bloomfield et al ., 2015 ). The outbreak case studies indicate that minimizing the contamination of textiles with microorganisms could reduce the risk of infections associated with healthcare textiles . This demonstrates that laundering is a critical process in ensuring the safety of healthcare textiles and that adequate decontamination should be ensured . Controls may include ensuring adequate decontamination of linen during laundering , monitoring for contamination of washing machines and rinse water and appropriate handling and storage of processed linen to prevent contamination .”
Efficacy of healthcare laundry processes
As we have seen , microbial reductions are associated with the proper washing and drying of healthcare textiles – specifically the combination of mechanical , thermal , and chemical factors all in action over the correct duration .
As Sehulster ( 2015 ) summarizes , “ Studies demonstrate that cool water wash cycles at temperatures of 71 degrees F to 77 degrees F can reduce microbial contamination when the wash cycle duration , the wash detergent , and the amount of laundry additive are all carefully monitored and controlled . Wash cycles with detergent and 71.6 degree F water removed easily dislodged soils and achieved a 3 log10 / cm2 reduction in microorganisms with the help of the washer ’ s agitation , rinsing , and drainage . Surfactants and detergents function to suspend more tightly bound soils . Use of low-temperature wash cycles has demonstrated effectiveness in either inactivation or removal of healthcare-associated pathogens such as Klebsiella pneumoniae , total coliforms , Staphylococcus aureus , enterococci , poliovirus , adenovirus , and pollen allergens . Use of hot water provides a sanitizing effect capable of producing microbial reduction of at least 5 log10 per square centimeter . A temperature of at least 160 degrees F for a minimum of 25 minutes is recommended frequently for traditional hot-water washing . Regardless of whether hot or cold water is used for washing , the temperatures reached in drying and especially during ironing provide additional microbicidal action , resulting in a reduction in the range of 0.5 to 2.0 log10 per square centimeter .”
Despite U . S ., UK and German programs to validate laundering processes for the decontamination of healthcare textiles and monitor the bioburden of processed linens , Owen and Laird ( 2020 ) assert that there is “ no standardized test methodology
to ensure that the sensitivity and reliability of methods being employed are consistent across the sector .” They explain that the variability in testing methods is problematic : “… the use of surface testing of processed linen ( RODAC plating ) such as in the TRSA and RKI guidelines may recover fewer microorganisms than elution methods , where samples are agitated in recovery media , due to limited contact with microorganisms trapped in the weave of textiles . This was concluded by Rabuza , et al . ( 2012 ), where the recovery of S . aureus and K . pneumoniae from textile samples was approximately 2 log10 lower from RODAC plating than from shaking in recovery media for 10 minutes at 300 rpm . There are also clear deviations in the threshold ( action ) levels of microorganisms to demonstrate that decontamination has been achieved between countries , indicating that different standards of decontamination are required between laundry operators . Standardization of microbiological methods and action levels employed in healthcare laundries would further strengthen the current validation of wash processes and bioburden of processed textiles is consistent across the sector and meets the required standard of decontamination to ensure the infection risk from processed laundry is low .”
The efficacy of laundering and processing is particularly important relating to the persistence of Clostridioides difficile spores , which exhibit thermotolerance and resistance to disinfection and have been demonstrated in studies to survive industrial laundering . As we have seen in the controversial study by Tarrant , et al . ( 2018 ), cotton bed sheets artificially contaminated with 7 log10 CFU / 25 cm2 C . difficile spores retained 4.95 – 5.27 log10 CFU / 25 cm 2 during a simulated industrial washer extractor cycle using thermal disinfection parameters ( ≥71 ° C for > 3 min ). A further 2.72 – 2.89 log10 CFU / 25 cm2 cross contaminated sterile textiles in the same wash indicating that the spores were not killed , but rather removed from the inoculated swatches and deposited on to other textiles .
Researchers say that given that C . difficile spores can be isolated from a CDI patient ’ s skin and that the diarrheal stool from CDI patients will give rise to high numbers of spores , it can be assumed that the attire and bed linens of patients will become contaminated with this pathogen . Potential C . difficile spore contamination of healthcare textiles via laundering was addressed by McLaren , et al . ( 2019 ), who evaluated the sporicidal properties of five laundry chemicals and then determined the ability of a peracetic acid ( PAA ) laundry cycle to inactivate and / or remove spores from cotton swatches during a simulated tunnel washer ( TW ) process .
In phase I , spore-inoculated swatches were immersed in alkaline detergent , sodium hypochlorite , hydrogen peroxide , or PAA for 8 minutes . In phase II , inoculated swatches were passed through a simulated 24-minute TW process employing five wash liquids . Spore survivors on swatches and in test chemical fluids in both studies were enumerated using standard microbiologic assay methods . In phase I , hypochlorite solutions achieved > 5 log10 spore reductions on swatches and > 3 log10 reductions for wash solutions . PAA achieved minimal spore reduction in the wash solution ( 0.26 log10 ). In phase II , the PAA equilibrium-containing process achieved a > 5 log10 spore reduction on swatches . In wash solution tests , the cumulative spore reduction peaked at > 3.08 log10 in the final module . The researchers concluded that the cumulative effects of a TW process , coupled with a PAA bleach agent at neutral pH , may render textiles essentially free of C .