percent confidence intervals ).”
If healthcare systems choose to proceed with a microbiological testing program for textiles , Sehulster ( 2015 ) indicates key considerations :
• The method must be scientifically rigorous and validated . If a method needs to be developed , it should undergo both intra-laboratory and inter-laboratory testing to define all aspects of the method , including aseptic technique , and ideally the validation results should be subject to scientific healthcare laundry and textiles scrutiny .
• The method should be statistically valid , providing a meaningful representative sampling of the HCT product output during the sampling period .
• The testing strategy should target the true end of the laundering process — when the textile goes to storage . As Sehulster ( 2015 ) explains , “ Given the nature of the problems leading to some of the outbreaks ( poor storage conditions supporting microbial proliferation ), spore-forming bacteria and fungi were identified , whereas S . aureus , P . aeruginosa , and E . coli were not . Microbiological testing will not detect contamination where we have seen it occur most often — in transit , in storage . Most importantly , there would need to be a plan of action for the infection preventionist at the hospital and the laundry managers when test results exceed the benchmark . Would a recall of HCTs be warranted under these circumstances , and if so , how far back from the current load ? If the HCT testing benchmark is not linked to patient outcomes and no infection prevention intervention is developed to address high heterotrophic plate counts , there may be no justification for testing .”
While laundry professionals may have a much better grasp of the concept of hygienically clean , clinical end users may be lacking awareness of the concept . Timo Hammer , CEO of Hohenstein Life Science and Care and managing director of the German Certification Association for Professional Textile Services , explains , “ When textiles are considered as hygienically clean it means that laundry processes have been proven to effectively prevent the transmission of pathogens to protect clinical users .”
“ For an HCT to be claimed as hygienically clean , the textiles , laundry and handling process should be thoroughly monitored ,” adds Andre Tomczyk , business development manager of microbiology at Hohenstein Germany . “ This normally means annual inspections of the laundry processes along with testing of surfaces that can re-contaminate properly laundered textiles . Of course , the most important metric would be the assurance that the textiles delivered to the clinical end user meet the science based limit values and this can be confirmed through objective selection and testing by independent third parties .”
It is essential for clinical end users of healthcare textiles to understand about the importance of testing to ensure that these linens perform as they are expected to . As Mead emphasizes , “ The testing of the textiles worn and used by the end user is the confirmation that all the process controls in the handling and laundry of the textiles are working . The process controls and policies are important in ensuring consistent application of the routines in the laundry facility , but the testing is the necessary confirmation that that those procedures are effective . In addition , the testing might reveal potential weak points in the individual process and thus lead to a continuous learning process within the respective organization . Hygiene is not ticking check-boxes on a list , but to live the hygiene process from A to Z .” Let us review the fundamental issues relating to healthcare textiles from an infection prevention and control perspective .
Contamination of healthcare textiles
As Sehulster ( 2015 ) pointed out , “ When textiles are heavily contaminated with potentially infective body substances ( blood , stool , urine ), they can contain 1 × 104 to 1 × 106 colony-forming units of bacteria per square centimeter of fabric . However , through a combination of soil removal , pathogen removal , and pathogen inactivation , contaminated laundry can be rendered hygienically clean . Hygienically clean laundry carries negligible risk to healthcare personnel and patients , provided that the clean textiles are not inadvertently contaminated before use .”
We know that healthcare textiles in close contact with patients for extended periods of time can become soiled with bodily fluids , blood , and skin scales , leading to contamination with potential pathogens . What ’ s more , HAI-causing pathogens have been shown to contaminate textiles in the clinical environment ; for example , Tarrant , et al . ( 2018 ) recovered 51 CFU / 25 cm2 of C . difficile spores from soiled hospital bed sheets of CDI patients , while Ohl et al . ( 2012 ) found that 92 percent of privacy curtains were contaminated with at least one bacterial species within one week , including S . aureus , MRSA and VRE .
Owen and Laird ( 2020 ) emphasize that many current studies into the contamination of healthcare textiles do not report the microbiological load or differentiate endogenous and environmental microorganisms which influences their risk as potential fomites ; around one-third of microorganisms isolated from textiles are from the participants ’ skin flora rather than healthcare-associated pathogens ( Wilson et al ., 2007 ). They note that , “ The majority of studies in the published literature do not attempt to correlate the observed microbiological contamination with the rate of HAIs and thus do not provide evidence for contaminated textiles acting as fomites .”
Microbial persistence on healthcare textiles also comes into play . Microorganisms generally exhibit lower survival on porous surfaces than on non-porous surfaces ( Bloomfield , et al ., 2015 ) yet they can survive on healthcare textiles for days to weeks . For example , S . aureus , E . coli and E . faecium survive on cotton for 21 days ( Riley , et al ., 2017 ; Fijan and Pahor , et al ., 2017 ) and S . aureus and E . faecium survive on polyester for up to seven days ( Riley , et al ., 2017 ). Fecal coliforms also survive for 120 days on cotton and blended textile at 25 degrees C (> 1.1 × 104 CFU / ml ), while few coliforms ( 1.1 × 102 CFU / ml ) survive on silk ( Colclasure , et al ., 2015 ). The greater survival of microorganisms on cotton compared to polyester and silk can be partly attributed to the moisture content of the different fibers ( Colclasure , et al ., 2015 ; Riley , et al ., 2017 ). Cotton absorbs moisture to a greater extent than synthetic materials such as polyester , which supports the enhanced survival of microorganisms on this fiber type ( Riley , et al ., 2017 ). Spore-forming bacteria exhibit even greater survival in the environment due to their resistance to desiccation , disinfection and high temperatures ( Dyer , et al ., 2019 ); C . difficile spores have been reported to persist on dry surfaces for five months ( Kramer , et al ., 2006 ).
One of the challenges of attempting to understand microbial persistence is that in vitro studies of microbiological survival on textiles may not adequately reflect real-world , in-use conditions . In particular , the loads of microorganisms employed are often high ( such as 105-109 CFU / ml ), which increases survival du-