INF ECT ION PR EVENT ION & CONT ROL
when dry. As most other disinfectants are only active when in their wet state, the standard tests reflect efficacy during or immediately after the wet phase. In addition, the tests are for short periods of time as efficacy over time is not expected with most other disinfectants.
The first two of these problems were solved by 2016, with the final problem solved by the middle of 2019. The data results in papers written since 2016 clearly show there are significant advantages in longevity and efficacy between the previous generations and the 5th generation SiQuats. Data to be published in the near future will show that dry surface testing over extended time periods is a far more accurate and reliable test for surface disinfection results than the current standard wet tests. In 2016, Dr. Phil Walker produced a test for persistence of Quats and SiQuats on surfaces. The test uses a dilute version of the copper/indicator complex, so that the small amount of the cation removed from the surface is not overwhelmed by the unreacted excess of the copper/indicator complex. Also, in 2016, the release of a biological
warfare test known as the Bacteria Specific Rapid Metabolic Assay (BSRMA), allowed us to see accurate numbers of live bacteria on surfaces, pre and post disinfection.14 In 2019, an MSc student at the University of Lincoln, competed testing using a newly developed procedure for dry surface testing. This methodology has been adapted and is used for testing of disinfectants against the COVID-19 virus.
Used in conjunction with standard culture techniques and PCR, these new tests and test methods are beginning to shine a light on the true levels of bio burdens on our hands, in our operating rooms and in our homes.
Results using 5th generation SiQuats We do not yet fully understand the impact of persistent disinfectant technologies on healthcare-associated infections (HCAIs). In the case of surgical site infections (SSI), the type of organism, as opposed to the species of organism, infecting a wound, is rarely seen to be an issue in most studies. It must be questioned as to why not? Surely the type of organism, will give an indication of where it came from, whether from the air, surfaces, or the skin of the operating staff. Species alone does in some respects give an indication, but genetic sequencing would give us a much better idea of the source of the organism.9
In early 2018 over a three-month period, a problem appeared in a specialist orthopaedic surgery unit, where 252 primary joint replacements were completed. 115 were hip replacements with 137 knee
replacements. The SSI rates for each were hips 6.1% and knees 5.8%. Prior to this, the SSI rates had been below 0.5% for both types of surgery.
The spike in infection rates was of great concern to all working in the unit. It was felt that the environmental microbial contamination must be to blame, although swabbing and standard culture produced no conclusive results. Using standard culture techniques, no relationship could be found between bacteria in the air or on surfaces and those colonising the surgical wounds. After swab testing using the BSRMA one of the operating rooms
technique,9
was treated with a 5th generation SiQuat, and one was not. The standard daily cleaning regime continued, and after the first week the 2nd room was then treated. As the BSRMA tests had revealed a similar number of bacteria left alive after cleaning with hypochlorite, a species study showed a streptococcus that was resistant to hypochlorite (this result was not available until Friday of the first week). BSRMA surface testing continued at various times of the day, most notably, prior to operating lists commencing each morning. The Veri Quat tests (Aqua tests) were also used to verify the presence of the SiQuats, and this testing continued for 6 months after treatment. Over the next 6 months 593 primary joint replacements were undertaken (294 hips, 299 knees); SSI rates were reduced to zero. While there can be no doubt that the Hawthorn effect used in Goodhearts law2
had some part to play in the reduction,
most notably, a further 6 months later, the Veri Quat tests started to show that the SiQuat was beginning to wear away, and infection rates began to rise again. Over that 6 months period (6-12 months
after surface treatment) 489 primary joint replacements were undertaken with four infections, equating to a 0.8% SSI rate. The
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same 5th generation SiQuat was then used to re-treat the areas where the Veri Quat tests had identified that the SiQuat was no longer present. The SSI rates returned to zero. Figure 1 shows the results of the BSRMA tests over the first week.
These results are of interest when we consider the most important time to surface test, which has to be just prior to the operating lists starting each morning. At this critical time, this evidence shows that the standard cleaning had shown no benefit to surface counts in the untreated room. This combined with the identification of a previously unseen resistant streptococcus, begs the question: ‘how many other operating theatres do not know what their surface contamination levels are prior to the commencement of surgical lists?’
Results
The following are a selection of test results of 5th generation SiQuats, as compared to more widely used disinfecting chemistries using the BSRMA surface tests.
Hands sanitisers Figure 2 shows the results of CFU counts on hands when comparing, washing with soap and water, alcohol 70% gel, alcohol 70% in water, Clinisept and a 5th generation SiQuat. Each group had 100 participants (200 hands), and the counts were averaged for each participant, and then in each group. There are now, numerous papers describing the poor results of bioburden on hands after using alcohol on its own, yet it is still the number one choice of hand sanitiser in most healthcare facilities around the world.2, 15-17
It is clear from the results,
and from numerous papers, that the effect of alcohol is limited to both time and species kill (Enterococcus, Norovirus etc). The fact that it also causes a dominant species change from Staphylococcus epidermidis
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