Decontamination
cardiopulmonary bypass. The investigation showed that these devices can harbour pathogens in the water circuits and generate bio-aerosols in the operating room, leading to airborne transmission.7 “We took cultures and air samples. Legionella
bacteria (also transmitted via aerosols) was found, as well as Mycobacterium chimaera, and due to the different skills sets and understanding of the water and aerosol exposure route we were able to deal with the outbreak in the Netherlands in just one week,” he commented. Showers can also present issues and Joost highlighted a paper which discussed an investigation that took place after a case of severe and lethal hospital-acquired infection, associated with Carbapenemase-producing Pseudomonas aeruginosa. The incident involved a man in his early 60s, with a left-sided pneumonectomy, who had undergone adjuvant radiotherapy. “We cultured all the patients, and they were negative on the ward, so we cultured the environment. The shower drains proved to be positive, but we didn’t understand the mode of transmission,” he explained. Air samples were taken, which proved to be positive with the exact same strain as the drain. The investigation mapped the ward, identifying eight positive rooms, and these were all interconnected with one sewage system – the microorganisms ‘grew’ and travelled from one side of the unit to another, and also became
airborne, which resulted in the infections. Joost pointed out that cleaning and disinfection of drains is not easy – it is not sustainable and finding solutions can be difficult. However, one possible low-cost solution is the use of removable custom-made plastic shower ‘tubs’ to prevent direct contact with the wastewater system of the shower area and, hence, prevent backsplash. In a study by Nurjadi et al (2021), this was found to prevent new acquisitions of OXA-48-Producing Enterobacter cloacae, related to hospital shower drains, 12 months post-implementation.8 The proximity of sinks to clinical areas
where central lines are prepared also needs consideration in hospital settings – this has been found to be a significant problem across high resource countries, as well as LMICs. However, in low and medium resource countries water can be especially problematic; UNICEF has reported that 70% of water at the point of consumption is contaminated. Water is also scarce in some parts of the world. Hospitals in South Africa, for example, are experiencing significant problems during the summer months due to the increase in temperatures. Alcohol- based hand rub can provide an alternative, Joost suggested. But should we also avoid locating sinks in patient areas? Joost highlighted a study which evaluated the effects of the removal of sinks from Intensive Care Unit (ICU) patient rooms and the introduction of ‘water-free’ patient care on Gram-negative bacilli (GNB) colonisation
rates. The overall colonisation rate dropped from 26.3 to 21.6 GNB/1000 intensive care unit (ICU) admission days. The reduction in GNB colonisation rate became more pronounced in patients with a longer ICU-Length of Stay (LOS): from a 1.22-fold reduction (≥2 days), to a 1.6-fold (≥5 days; P = 0.002), 2.5-fold (for ≥10 days; P < 0.001) to a 3.6-fold (≥14 days; P < 0.001) reduction. The study concluded that the removal of sinks from patient rooms and introduction of a method of ‘water-free’ patient care is associated with a significant reduction of patient colonisation with GNB, especially in patients with a longer ICU length of stay.9 While the proximity of the sink to the patient is significant, often sinks are not simply used for handwashing, which increases the risk of infection transmission even further. A study of handwashing sink activities, by Grabowski et al, found that handwashing accounted for only 4% of the total behaviours observed. The sinks were mainly used for getting rid of waste and video analysis showed that a significant number of activities involved the disposal of waste materials (patient or otherwise) which would provide nutrients that would promote microbial growth.10
Joost commented that we need to move to alcohol-based hand rub where appropriate and rethink waste management, focusing on the discarding of: l detergents and disinfectants l biological waste l drugs and infusion fluids, including antibiotics.
Decontamination He went on to discuss evidence-based decontamination, pointing out that research shows that the most common nosocomial pathogens (Gram-positives and Enterobacteriaceae) may survive on surfaces for months and can therefore be a continuous source of transmission if no regular preventive surface disinfection is performed.11 Using vancomycin-resistant Enterococci (VRE) as a marker organism, a study highlighted by Joost investigated the effects of improved environmental cleaning with and without promotion of hand hygiene adherence on the spread of VRE in a medical intensive care unit. The study found that environmental cleaning had the most impact.12 “The emphasis has been on hand hygiene, but I believe that cleaning and disinfection is even more important,” commented Joost. This is especially important for high-touch surfaces. He explained that systems are required to
evaluate environmental cleanliness. Common approaches include:
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