Decontamination of the healthcare environment

At the recent ASP National HCAI Symposium, Dr Tim Boswell, consultant medical microbiologist and infection control doctor, Nottingham University Hospitals NHS Trust, considered the question: “How important is the healthcare environment in HCAI pathogen transmission?” He pointed out that the emphasis has historically been on hand hygiene and, until recently, the environment was not considered as important as other sources of transmission. However, in recent years, evidence has started to emerge that the environment has an important role – even though it is not the most important source of transmission.1,2 Furthermore, the organisms that are covered by infection control targets survive well in the environment – including MRSA and C. difficile. “Healthcare workers’ hands (including gloved hands) can become contaminated with MRSA even without directly touching the patient. The fifth moment, in the World Health Organization’s Five Moments, (which requires hand cleansing after contact with the patient’s surroundings), is very important but tends to be the one that is forgotten,” commented Dr Boswell. “If you touch the patient’s notes or move their bedside table, this is sufficient to contaminate your hands. We also know that prior room occupancy with an infected patient is a risk factor for MRSA,” he continued, adding that there is also convincing evidence for C. difficile that the environment is important and that room decontamination reduces the risk of transmission.

The environment and MRSA

Dr Boswell provided an insight into how root cause analysis at the Trust revealed just how important the environment can be in terms of pathogen transmission: “In 2004, we had nine MRSA bacteraemias in one quarter, in our clinical haematology unit alone. I cannot begin to imagine what would happen if we reported this today – we now have a zero tolerance approach and our target last year, for the entire hospital, was just four. “We assumed that there was a problem on the haematology ward, associated with hickman lines, and screening was performed on admission and discharge. We found that patients that were coming in MRSA negative, went through the ward, and were still MRSA negative when they left. However, they would later return for their next cycle of chemotherapy, and would be screened on admission to find they were MRSA positive. This happened with several patients. There was no evidence of transmission on the ward, but somehow they were going home negative and coming back positive. All of these patients had been through the day case unit, however.” Dr Boswell presented a schematic of the day case unit, showing the clinical areas where patients attended for chemotherapy and blood products, along with the patient waiting areas. Environmental sampling was conducted using swabs, which indicated that the waiting area was contaminated. Settle plates were also used which proved positive for MRSA, including in the treatment area. “In just a couple of hours, MRSA was landing on horizontal surfaces where patients were having their hickman line care delivered. This is where they were encountering the colonisation of their hickman lines. What we subsequently discovered was that, on the day that we conducted this sampling, an MRSA positive patient was receiving day case treatment. There was no isolation facility and it was an open plan area, so we were forgetting the basic rules of segregation of the MRSA patient. “A significant factor was airborne dispersal of MRSA from the patient, who had a skin condition and heavy colonisation. The outbreak stopped when we took this patient, and some others who were colonised, and moved them away from this area, so they had their day case treatment separately. This goes to show just how important the environment can be,” Dr Boswell explained. “When the MRSA positive patient came in for their blood transfusion, into a side room, we took air samples. As soon as the patient came in we were able to detect MRSA in the air… There is a significant challenge in cleaning the environment after the patient has left – clearly, it is not just direct contact with the patient that needs to be addressed.”