Centre for Sustainable Disinfection and Sustainability, Bioscience Research Institute
https://research.thea.ie/handle/20.500.12065/3477
2024-03-28T21:34:49ZA proposed cleaning classification system for reusable medical devices to complement the Spaulding classification
https://research.thea.ie/handle/20.500.12065/4697
A proposed cleaning classification system for reusable medical devices to complement the Spaulding classification
Kremer, Terra; Rowan, Neil J.
A central tenet in infection prevention is the application of the Spaulding classification system for the safe use of medical devices. Initially defined in the 1950’s, this system defines types of devices and surfaces as being critical, semi-critical, and non-critical depending on how it will be used on a patient. Different levels of antimicrobial treatment, defined as various levels of disinfection or sterilization, are deemed appropriate to reduce patient risks of infection. However, a focus on microbial inactivation is insufficient to address this concern that has been particularly highlighted in routine healthcare facility practices emphasizing the underappreciated importance of cleaning and achieving acceptable cleanliness levels. A deeper understanding of microbiology has evolved since the 1950s that has led to a re-evaluation of the Spaulding classification along with a commensurate emphasis on achieving appropriate cleaning. Albeit underappreciated, cleaning has always been important as the presence of residual materials on surfaces can interfere with the efficacy of the antimicrobial process to inactivate microorganisms, as well as other risks to patients including device damage, malfunction, and biocompatibility concerns. Unfortunately, this continues to be relevant as attested by reports in the literature on the occurrence of device-related infections and outbreaks due to failures in processing expectations. This reflects in part increasing sophistication in device features and reuse, along with commensurate manufacturer’s instructions for use (IFU). Consequently, this constitutes the first description and recommendation of a new cleaning classification system to complement use of the traditional Spaulding definitions to help address these modern-day technical and patient-risk challenges. This quantitative risk-based classification system highlights the challenge of efficient cleaning based on the complexity of device features present as an isolated variable impacting cleaning. This cleaning classification can be used in combination with the Spaulding Classification to improve communication of cleaning risk of a reusable medical device between manufacturers and health care facilities and improve established cleaning practices. This new cleaning classification system will also inform future creation, design-thinking and commensurate innovations for the sustainable safe reuse of important medical devices.
2023-12-14T00:00:00ZPulsed ultraviolet (PUV) disinfection of artifcially contaminated seawater seeded with high levels of pathogen disease indicators as an alternative for the shellfish industry depuration systems
https://research.thea.ie/handle/20.500.12065/4516
Pulsed ultraviolet (PUV) disinfection of artifcially contaminated seawater seeded with high levels of pathogen disease indicators as an alternative for the shellfish industry depuration systems
Fehrenbach, Gustavo Waltzer; Murphy, Emma; Pogue, Robert; Carter, Frank; Clifford, Eoghan; Major, Ian; Rowan, Neil J.
The increase in pathogen levels in seawater threatens the safety of entire aquatic ecosystems. Foodborne pathogens can potentially accumulate in shellfish, especially in filter feeders such as bivalves, requiring an efficient depuration process before consumption. Alternative approaches to promote a cost-efficient purge at depuration plants are urgently needed. A small prototype pulsed ultraviolet (PUV) light recirculation system was designed, and its depuration potential was tested in a seawater matrix artificially contaminated with high levels of microbial pathogens Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Bacillus cereus and Candida albicans. The analysis of treatment parameters including voltage, number of pulses and duration of treatment was performed to ensure the highest reduction in contaminant levels. Optimal PUV disinfection was attained at 60 pulses/min at 1 kV for 10 min (a UV output of 12.9 J/cm2). All reductions were statistically significant, and the greatest was observed for S. aureus (5.63 log10), followed by C. albicans (5.15 log10), S. typhimurium (5 log10), B. cereus (4.59 log10) and E. coli (4.55 log10). PUV treatment disrupted the pathogen DNA with the result that S. aureus, C. albicans and S. typhimurium were not detectable by PCR. Regulations were reviewed to address the applicability of PUV treatment as a promising alternative to assist in the reduction of microbial pathogens at depuration plants due to its high efficiency, short treatment period, high UV dose and recirculation system as currently employed in shellfish depuration plants.
2023-05-08T00:00:00ZA review of Spaulding's classification system for effective cleaning, disinfection and sterilization of reusable medical devices: viewed through a modern-day lens that will inform and enable future sustainability
https://research.thea.ie/handle/20.500.12065/4463
A review of Spaulding's classification system for effective cleaning, disinfection and sterilization of reusable medical devices: viewed through a modern-day lens that will inform and enable future sustainability
Rowan, Neil J.; Kremer, Terra; McDonnell, Gerald
Despite advances in medicine and innovations in many underpinning fields including disease prevention and control,
the Spaulding classification system, originally proposed in 1957, remains widely used for defining the disinfection and
sterilization of contaminated re-usable medical devices and surgical instruments. Screening PubMed and Scopus databases
using a PRISMA guiding framework generated 272 relevant publications that were used in this review. Findings
revealed that there is a need to evolve how medical devices are designed, and processed by cleaning, disinfection (and/
or sterilization) to mitigate patient risks, including acquiring an infection. This Spaulding Classification remains in use
as it is logical, easily applied and understood by users (microbiologists, epidemiologists, manufacturers, industry) and
by regulators. However, substantial changes have occurred over the past 65 years that challenge interpretation and application
of this systemthat includes inter alia emergence of newpathogens (viruses, mycobacteria, protozoa, fungi), a
greater understanding of innate and adaptive microbial tolerance to disinfection, toxicity risks, increased number of
vulnerable patients and associated patient procedures, and greater complexity in design and use of medical devices.
Common cited examples include endoscopes that enable non- or minimal invasive procedures but are highly sophisticated
with various types of materials (polymers, electronic components etc), long narrow channels, right angle and heat-sensitive components and various accessories (e.g., values) that can be contaminated with high levels of microbial
bioburden and patient tissues after use. Contaminated flexible duodenoscopes have been a source of several significant
infection outbreaks, where at least 9 reported cases were caused by multidrug resistant organisms [MDROs] with no
obvious breach in processing detected. Despite this, there is evidence of the lack of attention to cleaning and maintenance
of these devices and associated equipment. Over the last few decades there is increasing genomic evidence of
innate and adaptive resistance to chemical disinfectant methods along with adaptive tolerance to environmental
stresses. To reduce these risks, it has been proposed to elevate classification of higher-risk flexible endoscopes (such
as duodenoscopes) from semi-critical [contact with mucous membrane and intact skin] to critical use [contact with
sterile tissue and blood] that entails a transition to using low-temperature sterilization modalities instead of routinely
using high-level disinfection; thus, increasing the margin of safety for endoscope processing. This timely review addresses
important issues surrounding use of the Spaulding classification system to meet modern-day needs. It specifically
addresses the need for automated, robust cleaning and drying methods combined with using real-time
monitoring of device processing. There is a need to understand entire end-to-end processing of devices instead of
adopting silo approaches that in the futurewill be informed by artificial intelligence and deep-learning/machine learning.
For example, combinational solutions that address the formation of complex biofilms that harbour pathogenic and
opportunistic microorganisms on the surfaces of processed devices. Emerging trends are addressed including future
sustainability for the medical devices sector that can be enabled via a new Quintuple Helix Hub approach that combines
academia, industry, healthcare, regulators, and society to unlock real world solutions.
2023-03-22T00:00:00ZCurrent decontamination challenges and potentially complementary solutions to safeguard the vulnerable seafood industry from recalcitrant human norovirus in live shellfish: Quo Vadis?
https://research.thea.ie/handle/20.500.12065/4405
Current decontamination challenges and potentially complementary solutions to safeguard the vulnerable seafood industry from recalcitrant human norovirus in live shellfish: Quo Vadis?
Rowan, Neil J.
Safeguarding the seafood industry is important given its contribution to supporting our growing global population.
However, shellfish are filter feeders that bioaccumulate microbial contaminants in their tissue from wastewater
discharged into the same coastal growing environments leading to significant human disease outbreaks unless appro priately mitigated. Removal or inactivation of enteric viruses is very challenging particularly as human norovirus
(hNoV) binds to specific histo-blood ligands in live oyster tissue that are consumed raw or lightly cooked. The regula tory framework that sets out use of clean seawater and UV disinfection is appropriate for bacterial decontamination at
the post-harvest land-based depuration (cleaning) stage. However, additional non-thermal technologies are required
to eliminate hNoV in live shellfish (particularly oysters) where published genomic studies report that low-pressure
UV has limited effectiveness in inactivating hNoV. The use of the standard genomic detection method (ISO 15,
216–1:2017) is not appropriate for assessing the loss of infectious hNoV in treated live shellfish. The use of surrogate
viral infectivity methods appear to offer some insight into the loss of hNoV infectiousness in live shellfish during de contamination. This paper reviews the use of existing and potentially other combinational treatment approaches to en hance the removal or inactivation of enteric viruses in live shellfish. The use of alternative and complementary novel
diagnostic approaches to discern viable hNoV are discussed. The effectiveness and virological safety of new affordable
hNoV intervention(s) require testing and validating at commercial shellfish production in conjunction with laboratory-based research. Appropriate risk management planning should encompass key stakeholders including local govern ment and the wastewater industry. Gaining a mechanistic understanding of the relationship between hNoV response
at molecular and structural levels in individually treated oysters as a unit will inform predictive modeling and appropriate treatment technologies. Global warming of coastal growing environments may introduce a contaminant challenges (such as invasive species); thus, underscoring need to develop real-time ecosystem monitoring
of growing environments to alert shellfish producers to appropriately mitigate these threats.
2023-02-24T00:00:00Z