Hidden dangers in hospitals: The risk of pathogen transmission via keyboards
Surfaces in healthcare environments can be contaminated with microorganisms that cause healthcare-associated infections. Special attention is paid to areas near patients, but less so to surfaces outside the patient zone, and the example we will refer to further concerns the keyboards of laptops, computers, and hospital equipment. Disinfecting keyboards and other common devices is essential to prevent the spread of microorganisms.
Keyboards from nursing stations in three hospitals and a dental office were analyzed for bacterial contamination. The surfaces were pre-treated to remove planktonic bacteria, so it was assumed that any remaining microorganisms were associated with biofilm. Bacterial transfer from the keyboards was studied following wiping with sterile water or sodium hypochlorite. The presence of multi-drug resistant organisms was verified through selective culture.
The results of these analyses can provide important insight into the effectiveness of cleaning and disinfection protocols used in healthcare facilities and can guide efforts to improve hygiene and safety within them. It is essential that methods for cleaning and disinfecting keyboards and common devices are adapted to ensure the effective elimination of pathogenic microorganisms and to minimize the risk of infection transmission in the medical environment.
Contaminated surfaces in the healthcare environment represent a significant risk factor for healthcare-acquired infections. This environment harbors a variety of pathogens, including multi-drug resistant organisms, which can survive on surfaces for extended periods of time. For example, bacteria such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci can persist on dry surfaces for over a year.
It is essential to take appropriate measures for the regular cleaning and disinfection of these surfaces to reduce the risk of infection transmission. The use of disinfectants specifically formulated for the medical environment, such as GLUTACIDE® – Concentrated disinfectant, can contribute to the elimination and inactivation of pathogenic microorganisms, including drug-resistant ones, ensuring a safe environment for patients and medical staff.
It is important to pay special attention to cleaning and disinfection protocols and procedures, and their implementation should be closely monitored to ensure effectiveness and compliance with hygiene and safety standards. By adopting these measures, healthcare facilities can contribute to reducing the incidence of healthcare-associated infections and protecting the health and safety of both patients and medical staff.
Surfaces and devices in the patient's immediate environment are not the only potential source of infection. Frequently touched objects can facilitate the transfer of pathogens even when they are not in the immediate vicinity of patients. Personnel in healthcare facilities can transmit pathogens from surfaces, a fact aggravated by poor adherence to hand hygiene. Frequently touched surfaces outside the patient area include objects such as phones or computer keyboards.
Although evidence of computer keyboard contamination is well-established, there are no studies on the transmission of clinically significant microorganisms from keyboards to hospital staff and patients. Furthermore, no one has yet investigated the possibility of bacterial transfer from the keyboard directly after treatment with a chlorine-releasing agent. In a comprehensive study[1], researchers investigated the presence of pathogens on 52 routinely cleaned hospital keyboards from four UK healthcare facilities, then analyzing the potential for bacterial transfer after wiping with sterile water or sodium hypochlorite.
Research methods
Sample collection and selection
The used keyboards were collected from a 1,000-bed Welsh university hospital, a 500-bed Scottish district general hospital, a 1,700-bed British university hospital, and a Scottish dental office. The origin of the keyboards included adult intensive care units, oncology, malignant hematology, trauma, and orthopedics wards. From each keyboard, keys of the same size with a similar frequency of English letters (A, E, T, and O) were randomly selected for the swab test and two transfer tests. In total, 52 keys from 13 keyboards were investigated for the presence of microorganisms.
Sample pre-treatment
To remove visible dirt and planktonic microbes, all key samples were treated three times for 1 minute with 30 ml of sterile water.
Swab test
A sterile cotton swab was applied to the keyboard keys 3 times vertically and 3 times horizontally. The swab was then applied to a tryptone soy agar plate, following the same movement pattern and swab pressure. The sample was considered bacteria-free when no bacterial growth was observed on the TSA plate after overnight incubation at 37°C.
Wiping with sterile water and 1,000 ppm NaOCl.
The 1,000 ppm NaOCl solution was prepared by mixing sodium hypochlorite, a 10-15% active chlorine solution, in distilled water to the final concentration of 1,000 ppm. Sterile distilled water or the 1,000 ppm NaOCl solution was combined with a disposable microfiber cloth. The treated keys were left for 2 min at room temperature (contact time) before the transfer test.
Transfer test
After wiping with sterile water or 1,000 ppm NaOCl, the key samples were pressed onto neutralizing agar with a pressure of 150 g to mimic a typist's finger touch. In total, 25 consecutive presses were performed for each sample. The agar plate was then incubated at 37°C overnight. The sample was positive for bacterial transfer when at least one depression resulted in bacterial growth.
Results and discussion regarding keyboard disinfection
The sampled keyboards had been used for a prolonged period of time – from 6 months up to several years – depending on the healthcare facility. After collection, all keyboard samples were visibly dirty. Keyboards are difficult to clean due to irregular surfaces and low material compatibility with disinfectant products.
No bacteria were obtained from any keyboard sample through swabbing. However, the fact that it was not possible to isolate planktonic or loosely attached bacteria does not necessarily equate to surface safety.
It is also debatable whether swabbing, one of the most commonly used techniques to determine surface contamination, is actually the best method for detecting surfaces. It has been shown that the recovery of bacteria from traditional cotton swabs is unsatisfactory. Bacteria, including pathogens, reside on surfaces within the biofilm, which is a complex community of microorganisms.
According to the National Patient Safety Agency recommendations, it is suggested to perform a weekly cleaning of keyboards using detergent wipes instead of agents containing chlorine. Consequently, in hospitals, it is likely that keyboards are cleaned regularly only with detergent, and the disinfection process is implemented only in case of crisis situations or during an infection outbreak. However, in many hospitals, protocols are adjusted to include the use of disinfectants, often in the form of solutions containing chlorine, especially when different types of microorganisms are managed, including COVID-19. In this context, specialized products such as KLINWIPES® – Disinfectant wet wipes for surfaces, become essential for ensuring a sterile and safe environment in medical institutions. The use of these disinfectant wet wipes can contribute significantly to reducing the risk of infection transmission and protecting both patients and medical staff.
But even if keyboards were treated with chlorine-releasing disinfectants, the findings indicate that this would still not be adequate for complete decontamination. After wiping with 1,000 ppm chlorine, 54% of the keys were still contaminated and, therefore, potentially capable of transferring bacteria.
Verifying that a surface has been properly cleaned/disinfected is a challenge, as no standardized monitoring method has been established. Swabbing is the usual method, but there is concern regarding its effectiveness, as bacterial recovery from cotton swabs could be less than 25%; mainly due to the low rate of bacterial release from swabs into the solid nutritive medium/intermediate diluent.
Some hospitals use ultraviolet C (UV-C) disinfection technology as part of the final cleaning. UV-C has been shown to be effective against major hospital environmental pathogens, which include the bacteria that can be found on keyboards. However, data suggest the contrary, and the impact of UV-C in preventing pathogen transmission has not yet been reported.
The microorganisms found on surfaces are not always pathogenic, and to assess their presence, keyboards were subjected to analyses with selective plates. In one study, it was found that the Welsh unit showed the highest percentage of antibiotic-resistant microorganisms, recording 25%, 63%, and 88% of positive samples. Contamination levels were also identified in samples taken from a Scottish hospital. In contrast, the Scottish dental office was the only unit that showed samples with no bacterial growth on the selective plates tested in this study. This finding can be attributed to the different environment in an outpatient clinic, where the risk of contamination is potentially lower compared to hospital wards such as those for kidney disease, intensive care, and hematology, where patients are more susceptible to infections. In the context of managing hygiene and preventing infection transmission, special disinfectants, such as KLINCIDE AF – Surface disinfectant, play a crucial role in ensuring a sterile and safe environment in the medical setting. The use of these disinfectants can contribute to reducing the risk of healthcare-associated infections and protecting the health of patients and medical staff.
Coliforms and non-lactose fermenting Gram-negative bacteria species were the most prevalent on samples from the English hospital and the Scottish dental office, with 75% and 100%, respectively, of MacConkey agar positive for bacterial growth. From samples from the Welsh and Scottish hospitals, 25% and 20%, respectively, were contaminated.
As demonstrated, clinically relevant pathogens on keyboards are still transferable after decontamination with 1,000 ppm NaOCl, which suggests that current cleaning/disinfection protocols might not be effective for combating infections. The study highlights the need for improving keyboard disinfection products: it is important that the products demonstrate effectiveness against dry surface biofilms.
In the context of the medical environment, prioritizing easy-to-clean devices is essential for maintaining a high standard of hygiene. In particular, keyboards used in hospitals should be constructed from materials that allow the use of stronger cleaning solutions, ensuring effective removal of pathogens. Also, their design should be conceived in such a way as to minimize cracks or spaces where dirt and bacteria can accumulate, such as under the keys. The choice of professional hospital disinfectants is crucial for ensuring a sterile and safe environment. These disinfectants are specifically formulated to eliminate a wide range of pathogens and are adapted for use in medical spaces, respecting the strict hygiene and safety standards imposed in such sensitive environments. By adopting these measures and carefully choosing cleaning equipment and solutions, hospitals can reduce the risk of contamination and contribute to protecting the health of medical staff and patients.
Conclusions
In conclusion, disinfecting keyboards and shared devices in healthcare settings is an essential measure for preventing the spread of pathogenic microorganisms and reducing the risk of healthcare-associated infections. Studies demonstrate that these surfaces can be significant sources of contamination, and their cleaning and disinfection are crucial for maintaining a sterile and safe environment in hospitals and clinics.
Although there are protocols and recommendations for the cleaning and disinfection of these devices, research indicates that current methods may not always be sufficiently effective. It is important to pay special attention to the materials and design of keyboards to ensure they are easy to clean and disinfect, thereby minimizing the risk of bacterial accumulation.
The use of disinfectants specifically formulated for medical environments and disinfectant wipes can contribute to ensuring optimal cleanliness and hygiene in healthcare settings. Furthermore, the adoption of technologies such as UV-C disinfection can provide an additional method for combating contamination and ensuring a sterile environment.
By implementing these measures and carefully choosing equipment and cleaning solutions, hospitals and clinics can reduce the risk of healthcare-associated infections and contribute to protecting the health of medical staff and patients.
