Are floors an underappreciated risk of pathogen dissemination?

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Floors in healthcare facilities are currently considered non-critical surfaces with low to no risk in contributing to a healthcare-associated infection. While non-critical surfaces that are frequently touched by the hands of a patient or staff are acknowledged to be a potential secondary source of transmission of pathogens that can cause an infection, floors are rarely touched by hands and have not been directly implicated in an outbreak in healthcare facilities. However, according to several recent studies, floors cannot and should not be considered risk free of dangerous pathogens.

 

Floors must be addressed in a robust infection prevention program so that they are properly cleaned, sanitized and maintained to prevent the transition of dangerous germs.

Floor Cleaning Guidelines

The CDC's standard healthcare cleaning guidelines[1] use seven criteria to determine if a non-critical surface should be disinfected. They conclude that floors meet five of the seven points, making floors worthy of disinfection not just when they are visibly contaminated with blood or body fluids or when spills occur. Unless there is visible contamination, the CDC recommends cleaning and/or disinfecting floors on a regular basis, including at patient discharge, but with no defined cleaning frequency.

The CDC "Guidelines for Environmental Infection Control in Health-Care Facilities"2 also discuss floors. In this document, floors are referred to as housekeeping surfaces and are grouped with other surfaces with minimal hand contact. Cleaning is recommended for floors on a regular basis, when soiling and spills occur, and on patient discharge, but daily disinfection is not recommended and the guidelines include a statement that "extraordinary cleaning and decontamination of floors in healthcare settings is unwarranted" (p 75). While use of a disinfectant on floors is optional for a facility, it is clear from the guidelines that the evidence at the time did not support recommending daily disinfection.

The SHEA/IDSA "Strategies to prevent Clostridium difficile infections in acute care hospitals: 2014 update" lists floors as part of the environment ("Furnishings in the room, such as over bed tables, bedrails, furniture, sinks, floors, commodes, and toilets.") This guideline recommends cleaning and disinfection of the environment, but only with a sporicidal agent during an outbreak or hyperendemic situation.

Respiratory Droplet Dissemination

Breathing, talking, sneezing and coughing can easily expel respiratory droplets into an environment each with their own data related to air flow, quantity of droplets, droplet size expelled from the body, and distance droplets can travel. Air motion moves respiratory droplets between people. These droplets can be inhaled or swallowed, settle on people, surfaces or floors and quickly spread infection. The quantity, size and distance that the droplets travel can affect the time it takes to them for them to evaporate or settle onto surfaces or floors.

Due to the airflow created by walking — which is affected by body size, body shape and even arm swing — it's difficult to determine how droplets will move. Respiratory droplets, skin cells and other organic material that settles onto floors can be disturbed by walking and pulled along in the body wake for some distance. When the person stops walking, those droplets and skin cells suspended in the air below the waist can settle onto the floor or be lifted up into the breathing zone and inhaled by the body's thermal plume. If these droplets contain infectious bacteria or viruses, even if they have already settled onto the floor, they pose a risk to healthcare workers, patients and visitors.

Pathogens Spreading from Floors

A recent study published in the American Journal of Infection Control[2] determined that hospital room floors harbor dangerous bacteria. The study swabbed floors in rooms with and without patients who have a C. diff infection. The floors were frequently contaminated with MRSA, VRE, and C. diff. In rooms with a C. diff patient, floors were more likely to be contaminated with any of the three pathogens, but C. diff was the most commonly detected of the three in approximately 50 percent of the rooms.

The study also found that 41 percent of rooms had one or more objects, like personal items, medical devices and bed linens or towels, in contact with the floor and patient or healthcare workers' hands. After healthcare workers handled a high-touch object in contact with the floor, hand swabs detected MRSA at 18 percent, VRE at 6 percent, and C. diff at 3 percent. This indicates a possible route of dissemination of pathogens from the floor to high-touch surfaces in the near-patient zone.

A separate experiment (Koganti et. al., 2016)[3] seeded a patient room floor with a non-pathogenic virus and sampled high-touch surfaces daily for three days to determine the level of floor transfer contamination. The virus was detected on multiple surfaces in all patient rooms on the day after the virus application. Virus contamination was heavier closer to the patient and was also detected in other patient rooms and at the nursing station, which were not intentionally seeded with the virus.

This experiment demonstrates that healthcare workers and visitors would have contaminated their feet by standing at the patient bedside, risking exposure while taking their shoes off. They may have also contaminated their hands through touching or removing their footwear or they may have become contaminated if body movements disturbed the virus from the floor and moved it into the air. Additionally, the patient may have contaminated their sheets with their feet by walking through the virus and then climbing back into bed. The virus was then possibly further spread through hand contact by the patient or healthcare workers.

Footwear Contaminating Bedsheets

Two separate studies examined the role of contaminated footwear in transferring bacteria from the floor onto the bed sheets. In one study (Galvin, 2016)[4], patients received shoe covers prior to surgery and found contamination within five minutes of putting them on. The results also found that the shoe covers were contaminated at much higher levels after walking into the bathroom. Testing of the bed sheets showed that a significant number of bacteria, including pathogenic bacteria, were transferred to the bed sheets at the same time.

The other study (Mahida, 2016)[5] tested non-slip socks provided to patients in the UK and found that the socks were heavily contaminated with bacteria including MRSA and VRE.

Additional Contaminating Events

Other events that can spread contaminates include when small children visiting a patient crawl on the floor and then are placed in the patient's bed, when objects like presents, bags, and purses rest on the floor and are then passed to a patient, and when healthcare workers drop an object on the floor and then retrieve it without disinfecting the object. If the object is then used in providing care, it can contaminate the bed area.

Encouraging Health with Every Step

The above studies demonstrate that healthcare facilities need to take floor cleanliness seriously. To keep visitors, as well as healthcare workers and patients in safe, healthy conditions, every area of a facility must be cleaned – even low to no-risk surfaces like floors.

Peter Teska is a global infection prevention application expert with Sealed Air's Diversey Care division and can be reached at peter.teska@sealediar.com. Jim Gauthier is a senior clinical advisor with Diversey Care and can be reached at james.gauthier@sealedair.com.

 

The views, opinions and positions expressed within these guest posts are those of the author alone and do not represent those of Becker's Hospital Review/Becker's Healthcare. The accuracy, completeness and validity of any statements made within this article are not guaranteed. We accept no liability for any errors, omissions or representations. The copyright of this content belongs to the author and any liability with regards to infringement of intellectual property rights remains with them.


[1] Rutala WA, Weber DJ, "Guideline for disinfection and sterilization in healthcare facilities, 2008", Centers for Disease Control and Prevention, 2008. Retrieved from: https://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf

2 Sehulster LM, Chinn RYW, Arduino MJ, Carpenter J, Donlan R, Ashford D, Besser R, Fields B, McNeil MM, Whitney C, Wong S, Juranek D, Cleveland J. Guidelines for environmental infection control in health-care facilities. Recommendations from CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC). Chicago IL; American Society for Healthcare Engineering/American Hospital Association; 2004.

[2] Deshpande A, Cadnum JL, Fertelli D, Sitzlar B, Thota P, Mana TS, Jencson A, Alhmidi H, Koganti S, Donskey CJ. Are hospital floors an underappreciated reservoir for transmission of health care-associated pathogens. Am J of Infect Cont, 2017; 45: 336-338.  

[3] Koganti, et. al. Evaluation of hospital floors as a potential source of pathogen dissemination using a nonpathogenic virus as a surrogate marker. Infect Cont & Hosp Epidemiol, 2016: 37 (11): 1374-1377.

[4] Galvin, et al. Patient shoe covers: Transferring bacteria from the floor onto surgical bedsheets. Am J of Infect Control, 2016; 44: 1417-1419.

[5] Mahida and Boswell. "Non-slip socks: A potential reservoir for transmitting multidrug resistant organisms in hospitals", J of Hosp Infect, 2016; 94: 273-295.

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