March 01, 2014
12 min read

Infection control in hospitals: The role of environmental disinfection

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According to the Agency for Healthcare Research and Quality, health care-associated infections are the most common complication among people receiving hospital care.

Overall, the rate of health care–associated infections (HAIs) in the United States is decreasing, according to the CDC’s HAI Progress Report, released in March. However, there were still approximately 722,000 HAIs reported in 2012, translating to one HAI for every 25 patients. Among those, about 75,000 died.

Hospitals are fraught with bacteria and other microbes just waiting to infect patients who are often more susceptible to infections due to their illnesses. This is especially concerning as the rate of multidrug-resistant organisms continues to rise and cause infections that are becoming increasingly more difficult to treat.

Tara Palmore, MD, deputy hospital epidemiologist at the NIH Clinical Center, said the hospital environment can be a source for infections.

Tara Palmore, MD, deputy
hospital epidemiologist at
the NIH Clinical Center, said
the hospital environment
can be a source for infections.

Photo courtesy of Palmore T

Infection control is an important part of the culture in all hospitals, and environmental cleaning and disinfection is a key component of a comprehensive plan. Rigorous cleaning methods are required to ensure that rooms and equipment are safe for patients. However, some experts have said it does not often take the forefront role it should.

“Many hospitals are focused on the financial aspect of health care and not the quality outcomes, trying to make health care more cost-efficient,” Trish M. Perl, MD, MSc, professor at Johns Hopkins University School of Medicine and in the department of epidemiology at the Bloomberg School of Hygiene at Johns Hopkins, told Infectious Disease News. “Not everything is preventable, but is it worth it to invest the time and money to make sure rooms are clear of these organisms? Absolutely.”

Infectious Disease News discussed hospital infection control with key experts to identify important aspects that contribute to the prevention of infections in hospitals. This story is the first in a two-part series. This month, the focus is on environmental disinfection and cleaning in hospitals. Next month will focus on the importance of hand hygiene.

Increasing evidence

Historically, the role of the environment in the transmission of infections in hospitals has not always been appreciated, especially in the United States, according to Perl. Recent studies and data are changing this.

First, important pathogens, including MDR organisms and epidemiologically significant organisms such as Clostridium difficile and norovirus, among others, have been isolated from the environment, Perl said. Second, environmental sources have been linked to multiple outbreaks of these pathogens.

“The environment can serve as a point source, which means that multiple patients can develop infections from contamination at one site,” Tara Palmore, MD, deputy hospital epidemiologist at the NIH Clinical Center, told Infectious Disease News. “An example of that is a contaminated sink or ice machine, both of which have been cited in the literature as point sources of outbreaks in hospitals.”

According to Curtis Donskey, MD, associate professor of medicine at Case Western Reserve University and an infectious disease physician at Louis Stokes Cleveland VA Medical Center, two other lines of evidence have arisen in the past several years that have led to the environment being increasingly appreciated as a source for transmission of pathogens.

“We know that the hands of health care workers are the primary route for transmission of pathogens and it’s now recognized that they acquire these pathogens from the environment,” Donskey told Infectious Disease News. “Second, it has also been demonstrated that patients admitted to rooms where a previous patient was a carrier of a pathogen, their risk of acquiring the same pathogen is increased. These two things suggest very strongly that patients are picking up those organisms in the environment.”

Abundance of opportunities

Almost everything that comes into contact with a patient eventually becomes contaminated with the bacteria on that patient, according to Daniel Morgan, MD, MS, assistant professor of epidemiology and public health at the University of Maryland, which makes it easy for the bacteria to transfer between surfaces and people.

“The missing piece that we don’t know is how often this contamination results in transmission and then how often this transmission results in infection,” Morgan told Infectious Disease News. “There are expert guesses suggesting that 15% to 20% of hospital-acquired infections are due to the environment, but this isn’t known for sure.”

Hospital rooms are full of equipment, which makes it even easier to acquire infections via the environment. Devices, screens, monitors and tubes, among others, can all harbor bacteria. Hospital cleaning staff are not permitted to touch patient equipment, Morgan said, and it may not be known exactly whose duty it is to clean it. In addition, Perl said, the equipment is becoming increasingly complex and difficult to clean. Some people do not want to clean the equipment because of the fear they will ruin a costly instrument.

Trischa Perl

Trischa Perl

But perhaps more common and insidious is the contamination of normal, ordinary sources in hospitals, according to Palmore. Bacteria have been cultured from surfaces in the rooms several days after a patient with MDR bacteria leaves the room, Palmore said.

The infectious agents do not stay in the hospital room either. With nurses, doctors other health care workers entering patient rooms throughout the day, all it takes is for one person to touch a contaminated bedrail or telephone and transfer those bacteria to the nurse’s station, handrails or other public surfaces in the hospital.

Standard practices

Donskey said there is no gold standard for hospital disinfection. Procedures for disinfection vary by hospital and also by individual room circumstances.

For example, bleach is one of the most effective disinfectants in the market, but it is typically reserved for difficult pathogens such as C. difficile. But even then, it requires “elbow grease,” Palmore said, and it has to remain damp on surfaces for certain amount of time to kill the bacteria before it is removed with the required degree of vigor.

“Bleach is very effective and we routinely use it in units that have issues with C. difficile because it’s better at killing spores than any other surface disinfectant,” Palmore said. “But it is also caustic to surfaces and many people are very sensitive to bleach vapors, making its use a potential health concern for both patients and health care workers.”

Most hospitals use disinfectants with quaternary ammonium compounds, which are the “bread and butter” in hospital room cleaning, Palmore said, adding that some hospitals are switching to liquid hydrogen peroxide cleaners because they appear to be more effective in experimental studies.

There is some evidence that resistance to disinfectants is arising, particularly to the quaternary ammonium compounds that are most commonly used, but it is not clear whether this will be a clinically significant issue, Donskey said. There has been no resistance observed to bleach or alcohol-based disinfectants.

But there is no standard disinfectant, and it is important to determine the best and safest high-quality disinfectants to use, Perl said.

“This is an area where there are huge opportunities to improve,” Perl said. “We are increasingly identifying products that are better tolerated, which are less difficult on the environment in that they won’t destroy the ecologic balance. We have miles to go before we reach this point, though.”

Monitoring cleanliness

Currently, there is a disconnect between what needs to be done to clean and disinfect a hospital room and what is actually done, Donskey said.

“We have this disconnect in part because we don’t have ideal methods to monitor how well rooms are cleaned,” Donskey said. “For processing surgical instruments, bio-indicators are used to confirm that instruments have proper sterilization, but we don’t have as much confidence in the tools used to measure if a room has been properly cleaned.”

One common method is to apply fluorescent markers to high-touch surfaces before cleaning, then using UV lights after cleaning to determine the thoroughness of cleaning based on marker removal. This is a useful method to monitor cleaning, but it has limitations as a standalone process, Donskey said. There is also the possibility of culturing specific surfaces for particularly troubling bacteria, such C. difficile, perhaps in combination with fluorescent markers.

With sometimes only an hour between patients, there is no quick, effective method at measuring cleanliness in between each patient. Regardless, Perl said, it will be important to identify methods to effectively measure cleaning processes to determine whether the rooms are being cleaned adequately.

“When you look at a hospital room, nobody cleans it like you or your mother would clean your home bathroom,” Perl said. “It’s not part of the process or expectation to get on your knees and scrub a hospital room.”

Importance of cleaning staff

There is a significant variability in cleaning procedures between hospitals. Even within the hospitals, there is variability from person to person. Often under-recognized, hospital cleaning staffs are on the frontline of environmental disinfection, but they may not realize the importance of their role.

“Having dedicated people who are focused on cleaning and trained more than the average cleaning person is probably the key to a really clean environment,” Morgan said. “Cleaning staff are often low-paid individuals who are not trained well, and haven’t been considered an important part of how a hospital functions.”

Donskey said many hospitals are realizing the critical part that these workers play in the facility and are increasingly investing in education and other efforts to make these staff feel like they are part of the health care team.

But there are still issues, despite those efforts. There is high turnover in environmental service employees and there still is a need for more effective ways to monitor cleaning and disinfection. This is still an issue even if the cleaning staff are on board and well-trained.

New technologies

Room disinfection with hydrogen peroxide vapor, a “no-touch technology,” reduced the risk for MDR organisms, according to study results published last year in Clinical Infectious Diseases.

Patients who were admitted to a room that was decontaminated with hydrogen peroxide vapor were 64% less likely to acquire a MDR organism (incidence rate ratio [IRR]=0.36; 95% CI, 0.19-0.7). They were 80% less likely to acquire vancomycin-resistant enterococci (VRE; IRR=0.2; 95% CI, 0.08-0.52). Although the risk for acquiring C. difficile, MRSA and MDR gram-negative rods was reduced, this was not significant.

At ID Week 2012, new data demonstrated the promise of ultraviolet light as a disinfection method. Researchers from Duke University found that there was more than a 90% reduction in all three pathogens after using the UV light. This occurred in all locations sampled, both in direct light and indirect light. For Acinetobacter, there was a 98.1% decrease in colony-forming units; for VRE, there was a 97.9% decrease; for C. difficile, there was a 92.9% decrease.

Both have limitations. They are expensive, and hydrogen peroxide vapor increases the time necessary for cleaning, Morgan said. UV light may take less time, but it does not hit all the surfaces in the room.

“The data so far are good, but it’s hard to extrapolate from experiments whether one is more effective than the other for killing different types of bacteria or spores in patient rooms,” Palmore said. “I wouldn’t say that either is 100% effective.”

Adjuncts to standard cleaning

Perl said these new cleaning technologies are the wave of the future. They will not be the only cleaning method used, but they will be used as an adjunct to current cleaning methods.

“Cleaning staff are human and aren’t often rewarded for the work they’re doing,” Perl said. “If they have one of these new technological solutions to help them, this will go a long way to improving our cleaning. The novel technologies are far more effective at cleaning. The challenge is to figure out how to use them, when to use them and how to make them cost-effective.”

This is especially important because research done in vivo has shown that normal cleaning processes do not always get rid of all organisms. C. difficile and norovirus are two pathogens that are especially difficult to eradicate without draconian cleaning methods, Perl said, and because of this, it is difficult to avoid outbreaks.

The consensus is that the new technologies can be effective at eliminating even the most difficult bacteria, Donskey said.

“Hydrogen peroxide vapor is considered the gold standard for achieving excellent environment disinfection in hospital rooms,” Donskey said. “But because of the time it takes and the cost, it’s not something that can be used all the time. I view these automated technologies as an adjunctive measure that can be helpful as part of a multifaceted cleaning approach. The standard, though, is still manual cleaning and disinfection.” — by Emily Shafer


Agency for Healthcare Research and Quality. Ending Health Care-Associated Infections. Available at:
Anderson D. #36438. Presented at: ID Week 2012; Oct. 16-19, 2012; San Diego.

Passaretti C. Clin Infect Dis. 2013;56:27-35.

For more information:

Curtis Donskey, MD, can be reached at:
Daniel Morgan, MD, MS,
can be reached at:

Tara Palmore, MD, can be reached at:

Trish Perl, MD, MS,
can be reached at:

Disclosure: Donskey, Morgan, Palmore and Perl report no relevant financial disclosures.

There is evidence that antimicrobial copper surfaces help reduce environmental contamination. Do copper-coated surfaces have a promising future in hospitals?


Copper is a “no touch” mechanism that could be an attractive option.

Mounting evidence suggests that environmental contamination plays an important role in the acquisition of organisms and the development of HAIs. There is still a lot to know about that, especially what infections are more influenced by environmental contamination and the mechanisms of transfer. In our recent study, we were able to show that with copper surfaces, the rate of HAIs was significantly lower. Additionally, we were able to understand which objects in the room had a heavier microbial burden, namely bed rails, which may have posed the greatest risk for patients. Copper surfaces were able to reduce the burden on these objects and we postulated that this may have resulted in less transfer of organisms to patients and ultimately less infections. One question, which is left unanswered, is what we should consider a safe burden for patients, and future studies should try to focus on that.

There has been debate on whether it’s practical to put copper in hospital rooms, because of the significant cost. Generally speaking, it was less than $10,000 per room (or approximately 10% of material costs of the room) to surface the bedrails, call buttons, IV poles, overbed tables, data input devices and visitor chair armrests. However, it’s not known how much this would cost if the objects were mass produced. Statistics suggests that 5% of patients admitted to hospitals in the United States acquire an HAI and probably a higher proportion in ICUs. In a 20-bed ICU, with average hospital stays of 4 days, you might expect to take care of about 150 patients a month and those patients would acquire about seven to eight HAIs. If you outfit the ICU with copper surfaces, and if our data are correct, you could expect to reduce the rate of HAIs by a little more than 50%. The savings of three to four HAIs per month should result in significant cost savings over the course of the first year after installation.

Copper really is a “no touch” mechanism that could be an attractive option along with our other infection control measures to reduce HAIs. It holds great promise for the future, largely because we know that it reduces burden, and we have preliminary data that it reduces the risk of HAIs when used thoughtfully on objects near the patient. It doesn’t require any special care, it’s continuously active, and it doesn’t require changing behaviors of health care workers. There are unanswered questions, including how many copper surfaces need to be in the room and which patient populations copper surfaces may benefit the most. Our study needs to be replicated to further prove our results, as well as to see potential benefits outside the ICU. Additionally, sophisticated cost-analysis is needed and all of this will require cooperation between the industry and the scientists in the field.

Cassandra Salgado, MD, MS, is a professor at Medical University of South Carolina. Disclosure: Salgado’s study of the effect of copper surfaces in the ICU was supported by the United States Department of Defense, US Army Materiel Command Contract W81XWH-07-C-0053.


The evidence for copper is not there yet.

The first and most important message about copper surfaces is that it is clearly premature to judge their potential value because we don’t have appropriately detailed and controlled studies. We know that copper has good ability to kill vegetative bacteria in the laboratory, but we also know it doesn’t kill the bacteria as fast as disinfectants. Also, the ability of copper to kill C. difficile spores has not been adequately studied, but preliminary data are not encouraging.

Other issues, including surface maintenance issues, have yet to be clarified. Copper oxidizes and there are some observations suggesting it doesn’t work as well after a period of time. Copper surfaces have to be maintained properly and there have been no studies to clarify how to do so. Of prime importance is the issue of transmission of hospital-associated pathogens in the hospital. We know that MRSA, C. difficile, VRE and Acinetobacter, among others, exist on many different surfaces. Although there are lots of different surfaces that you can put copper on, there are also a lot of surfaces that you can’t, such as monitor touch screens and other plastic surfaces surrounding patients. It’s impossible to pinpoint exactly where the bacteria are.

Independent studies are very much needed to look at the true clinical efficacy of copper surfaces. The major limitation of the studies that have been done so far is that they have been preliminary studies that have not been able to control for critical confounders. For example, if you put copper in an ICU, it’s going to change the way people do routine cleaning. Since copper surfaces will never replace routine disinfection cleaning, its potential value can only begin to be assessed in this context. What needs to be evaluated is pathogen acquisition using prospective assessment (patient and environmental surveillance cultures) with and without copper surface enhancement in the setting of ongoing covert objective monitoring of routine disinfection cleaning as recommended by the CDC.

Such an approach is critical to objectively assessing many unproven technologies, including copper and other technologies like hydrogen peroxide vapor and UV machines, as well as the new disinfectants and cleaning materials being marketed. There needs to be carefully-done, independent studies first, and if there is some benefit, we have to look at the cost of the intervention. It is important to remember that it has only been about 8 years since the first two US studies were published that began to question the effectiveness of environmental hygiene in hospitals. Everyone wants quick and simple solutions, but we are still at an early stage of trying to make appropriate and useful decisions about these things. We just don’t have the evidence, one way or the other, to make good decisions regarding copper surfaces at this point.

Philip C. Carling, MD, is a professor of Clinical Medicine, Boston University School of Medicine. Disclosure: Carling reports no relevant disclosures.