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Published on: November 5, 2016
Sampling of Patient Radiation Therapy Thermoplastic Immobilization Forms Reveals Several Types of Attached Bacteria
Terrence J Ravine1, Patricia S Brewer2, Sarah E Bru3
1Department of Biomedical Sciences, University of South Alabama, Mobile, Alabama, USA.
Background:
Thermoplastic medical devices used during patient therapy have been shown to harbor microbes, including those causing healthcare-associated infections (HAI). This issue has not been previously evaluated for immobilization forms used during radiation therapy. The present study addresses this matter by sampling immobilization forms used during patient treatment to see if any microbes could be similarly recovered.
Methods:
Twelve head-only in-use patient forms were sampled at 3 radiation therapy facilities. Sampled form areas included cheeks, forehead, and nose. A site survey was also conducted to determine individual form characteristics and form handling procedures.
Results:
All twelve forms demonstrated at least one type of bacteria being recovered from sampled areas, several forms with multiple types. Bacterium was not recovered from the nose area of a single form, even though bacteria were recovered from the same form's cheeks and forehead areas. Recovered bacteria included Bacillus species spp. (21), coagulase-negative staphylococci or CoNS (19), Staphylococcus aureus (2), Enterococcus species (1), alpha-hemolytic (viridians) streptococci (1), and Gram-negative rods (1). Bacillus species spp. and CoNS were recovered from 10 of 12 (∼84%) forms in at least one sampled area. In addition, a single Bacillus spp. was also recovered from a water bath used to heat forms at one treatment facility.
Discussion:
The detected presence of several bacterial types on patient forms indicates that they can attach to and surviving, for a time, on form surfaces. Two of the bacteria recovered, namely S. aureus and Enterococcus spp. are confirmed HAI pathogens. The remainder are considered as opportunistic bacterial pathogens that can cause HAIs in debilitated patients. Of special concern is the recovery of several different species of the environmental bacterium Bacillus spp. at a higher level than CoNS, a normal skin bacterium. The ability of Bacillus spp. to form spores further enhances its survival capability on form surfaces. The source of the recovered bacteria, including Bacillus spp. was not determined.
Conclusion:
The presence of bacteria on stored patient form surfaces indicates that there is a real potential to transfer them to the patient during its reapplication. The actual potential for microbe transfer such as Bacillus spp. or its spores has yet to be determined. Consequently, care should be taken by radiation therapy personnel in handling forms during patient reapplication. Precautions such as donning a fresh pair of gloves and cleaning a form with an approved disinfectant can help to reduce and/or eliminate unintended microbe transfer to the patient wearing it. This procedure should also be considered for patients without apparent open or leaking wounds.
Insights
Bacteria were found on all tested radiation therapy immobilization forms, including potential healthcare-associated infection (HAI) pathogens like Staphylococcus aureus. This highlights the need for strict handling protocols to prevent microbe transfer to patients.
Area of Science:
- Microbiology
- Medical Device Sterilization
- Radiation Oncology
Background:
- Thermoplastic medical devices can harbor microbes, posing a risk for healthcare-associated infections (HAIs).
- Previous research has not evaluated microbial contamination on immobilization forms used in radiation therapy.
- This study investigates microbial presence on patient-used radiation therapy immobilization forms.
Purpose of the Study:
- To determine if microbes, including bacteria, are present on thermoplastic immobilization forms used during patient radiation therapy.
- To identify the types of bacteria recovered from these forms.
- To assess the potential risk of microbial transfer to patients.
Main Methods:
- Twelve in-use, head-only patient immobilization forms were sampled from three radiation therapy facilities.
- Sampling targeted areas included the cheeks, forehead, and nose.
- A site survey assessed form characteristics and handling procedures.
Main Results:
- All twelve forms yielded bacterial recovery from at least one sampled area; several had multiple bacterial types.
- Commonly recovered bacteria included Bacillus species (21 instances) and coagulase-negative staphylococci (CoNS) (19 instances).
- Pathogenic bacteria, Staphylococcus aureus and Enterococcus species, were also recovered.
Conclusions:
- The presence of bacteria, including potential HAI pathogens, on immobilization forms indicates a risk of transfer to patients.
- Bacillus species, capable of forming spores, were recovered at a higher rate than expected for a normal skin bacterium.
- Implementing strict handling procedures, such as glove use and disinfection, is crucial to minimize microbial transfer during patient reapplication.
