New technologies join forces with proven methods of hospital infection control
By Diana Swift
So far, the first two decades of the 21st century have been banner ones for lethal drug-resistant superbugs – Clostridium difficile (C. diff.) vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA). Add to that the spectre of viruses from Avian to Zika, with Ebola, MERS, and SARS in-between, outbreaks of which could someday tax Canadian hospitals.
The statistics are troubling: an estimated one in 10 adult inpatients will have some type of hospital-acquired infection, to the tune of 220,000 cases a year, and one in 12 will get a superbug infection, These cases can entail as much as $20,000 worth of extra treatment and extended stays at an overall annual cost of $1 billion. According to the Patient Safety Institute at least 8,000 infected patients die annually.
As the war on pathogens heats up, hospitals are using updated versions of tried-and-true methods: elbow grease enhanced by dedicated monitoring and feedback to cleaning staff. But newer technology is joining forces with traditional ways in the battle against bugs. According to the Ontario Agency for Health Protection and Promotion and the Healthcare Infection Control Practices Advisory Committee, newer techniques such as ultraviolet (UV) light cleaning and disinfectant fogging techniques should supplement, not replace, standard cleaning techniques. Still there are some intriguing new options either in use or on the horizon. (See sidebar: “New weaponry in the war on infections.”)
In agreement is Winnipeg-based Molly Blake, BN, president of Infection Prevention and Control Canada. “We need to make sure our basics are sound and to focus on strategies that we know work,” she says. “It’s always good to add new approaches. But resources, whether financial or human or structural, differ at different sites so new techniques can’t be applied evenly. Resources and therefore techniques are very site-specific.”
One low-tech method is stepped up adherence to traditional housekeeping to reduce the reservoir of microbes. For several years, Winnipeg’s St. Boniface Hospital has been auditing cleaning compliance using an invisible gel that fluoresces under UV light to audit surfaces wiped with disinfectant by cleaning staff. “At first staff was shocked to see that compliance was only about 50 per cent,” says Michelle Alfa, PhD, a consulting clinical microbiologist in Winnipeg. “We tracked this for many months and found that as long as we gave the cleaning staff continuous feedback and had them to come back and reclean missed surfaces, they were able to maintain compliance at more than 80 per cent. It made a big difference in the effort they made.”
In another study Alfa reported that replacing a cleaner with a daily hydrogen peroxide disinfectant with 80 per cent compliance significantly reduced the rates of inpatient MRSA, VRE, and C. diff. infections.
The audit approach has also been successful at the McGill University Health Centre in Montreal. “We do a lot of auditing using the gel and have had a hand hygiene and antibiotic stewardship program over the past five years,” says Dr Charles Frenette, medical director of Infection Control at the McGill University Health Centre (MUHC).
In other measures, MUHC’s newest addition, the Glen Site, features single rooms only to reduce patient-to-patient transmission and all rooms are HEPA-filtered. The site has a special medical device reprocessing centre and separate elevators for patients and equipment. “We’ve reduced infection with VRE and MRSA by more than 50 per cent and of C. diff. by 35 per cent,” Frenette says.
At Vancouver Coastal Health UV-C sterilization has helped reduce the microbial bioburden with a mobile RD unit that cleans bathrooms and patient rooms as well as operating rooms and endoscopy units. “We also have UVC lights embedded in the bathrooms of some single-patient rooms and some shared bathrooms, and that’s worked out very well,” says Dr Elizabeth Bryce, regional medical director for Infection Control at Vancouver Coastal Health. “Our C. diff. rates have gone down remarkably.”
In a 2016 study of shared hospital bathrooms, for example, Bryce and colleagues reported a 95 per cent reduction in surface bacteria and a 35–48 per cent reduction in airborne bacteria in a bathroom sterilized with UV-C light versus a control bathroom cleaned with standard measures.
Other stakeholders are looking at refitting hospitals with microbe-resistant surfaces made of copper, salt, and sharkskin-like plastic (see “New Weapons in the War on Bugs”). These are promising but will their price be worth it? “Ultimately, you need to assess where you might need to install new surfaces versus where you might reasonably apply them,” says Bryce. “We still lack a lot of information on how they hold up, how durable they are, how they interact with our standard disinfectants – and ultimately how cost-effective they are.”
Despite redoubled efforts, hospital-acquired infections will continue to occur, especially if new antibiotic development continues to lag behind drug resistance by emergent strains. According to Blake, what’s desperately needed in infection control is an integrated national surveillance system with cross-country monitoring of infections. “Currently we have no national database that addresses trends across the country and allows us to make connections. Surveillance is very fractured and piecemeal, leaving healthcare professionals at a disadvantage in protecting the public,” she says. Pointing to gaps in inter-provincial in data sharing during the SARS outbreak of 2003, Blake added, “A national database working with consistent definitions across regions is the next step we need to take.”
But effective surveillance will require resources, human and financial, and not all healthcare facilities are equally blessed with these. In its 2017 call for a pan-Canadian framework for preventing infection, Health Canada acknowledged that “Limited resources and infrastructure, particularly in some small hospitals and rural and remote regions, may also affect their ability to participate in surveillance programs.”
New weaponry in the war on infections
Microbial infighting defeats C. diff
Rival strains of Clostridium difficile use micro weapons to kill each other off and gain supremacy, and now British and U.S. scientists are engineering similar tools into a novel antibiotic agent with the potential to prevent or cure C. diff infection. Though still at the laboratory stage, the Avidocin-CD nanomachine binds to the S-layer on the bacterial cell surface and then, like warring C. diff bacteria, lethally drives a harpoon-like nanotube through the cell envelope (see image).
Canines contra Clostridium
At Vancouver Coastal Health Angus the Springer spaniel is sniffing out C. diff. in spots missed by cleaners or where recent transmission has occurred. Whether he detects a single spot or pervasive room contamination, he quickly goes into alert mode.
Let there be light!
- UV light has been used for years to disinfect rooms and equipment. A relative newcomer to Canada is the LightStrike PX-UV system (Xenex Disinfection Services, San Antonio, Tex.,), a portable robotic unit that pulses UV-C light via an environmentally friendly xenon gas bulb rather than a standard mercury bulb. Studies of LightStrike have shown it can reduce infections, but its cost is relatively high, with per-unit prices, including a year’s servicing, ranging from USD $137,250 to $147,750.
- Blue-violet light can also sterilize. A new two-mode LED ceiling fixture called Indigo-Clean by Kenall in Kinosha, Wis., uses “white disinfection” while a room is occupied and provides ambient light, while an “indigo disinfection” mode provides more power without ambient light. Staff and patients can safely occupy the room during both modes, but decontamination with blue-violet light can take several hours versus minutes with UVC light. Unlike UV-C, blue-violet light does not damage rubber or plastic.
- In another photic application, UVC light is taking aim at germ-dense mobile devices. Already in use at several Canadian hospitals, the CleanSlate UV Sanitizer is a compact countertop machine that UVC irradiates cellphones, remote controls, and tablets for 30 seconds, and simultaneously reminds users to sanitize their hands. Its no-touch lid is made of antibacterial copper. The Toronto-based manufacturer’s prototype device killed 99 per cent of MRSA bacteria and C. diff. spores left on precleaned surfaces, and the next step is to see if this product can actually reduce hospital-acquired infections. The cost ranges from about $4,900 to $9,500, potentially allowing for several devices per institution.
Infertile breeding grounds
For millennia, humans have used salt to preserve food from bacterial contamination. Now Edmonton-based Outbreaker Solutions Inc. has harnessed the antimicrobial force of compressed salt, producing coverings for high-touch surfaces such as doorknobs, taps, bed railings, and toilet handles. Currently under review by the U.S. Environmental Protection Agency, it’s also being tested in a phase 2 trial at the University of Alberta, and may be on the Canadian market by 2019.
The red metal
Since ancient times copper containers have been used to preserve the quality of water, and now the red metal and its alloys are being turned to infection reduction in healthcare settings. Replacing standard work surfaces with copper has been shown to reduce microbial burden in hospitals around the world but so far not in Canada. One study reported that a copper surface also significantly reduced the microbial burden of a nearby non-copper surface in a phenomenon known as the halo effect). A 2015 study at the Medical University of South Carolina in Charleston reported that patients in ICUs with copper alloy surfaces had a significantly lower rate of incident hospital-acquired infections or colonization with MRSA or VRE than those in standard rooms.
Similar results emerged from a Vancouver Coastal Health pilot study, which found rooms in a transplant centre reengineered with copper surfacing had a highly significant reduction in microbial load versus regular rooms.
A plastic sheet whose ridged texture mimics the denticles on sharkskin is being investigated as a chemical-free inhibitor of bacterial growth. Sharklet Technologies, Inc., headquartered in Aurora, Colo., is testing an anti-adhesion surface whose diamond pattern interferes with the ability of microorganisms to take hold – just as sharkskin repels algae and barnacles. Developed to ward off adhesions on naval ships, the material is being evaluated to see if it can actually reduce infections in hospitals. In one study Sharklet harboured 94 per cent fewer MRSA bacteria than a smooth surface, and even outperformed copper
Surgical drapes impregnated with the iodine-based disinfectant iodphor have been tested to prevent surgical infections. One study, however, found no difference in C-section infection rates between sterilizing with an alcohol scrub plus iodophor drapes and with the scrub alone.
As for microbiocidal wall and other paints for preventing infections in healthcare settings, a 2017 review by the Ottawa-based Canadian Agency for Drugs and technologies in Health turned up no relevant data on that method.