Sampling of Patient Radiation Therapy Thermoplastic Immobilization Forms Reveals Several Types of Attached Bacteria

Microorganisms isolated from thermoplastic masks and storage racks in head and neck cancer patients with radiation dermatitis

Healthcare-associated infections (HAIs) remain a critical public health issue, as they contribute to prolonged treatment duration, increased healthcare costs, and heightened risks of morbidity and mortality. In head and neck cancer patients undergoing radiotherapy, thermoplastic masks (TMs), which come into direct contact with the skin, represent a potential vector for infection. Additionally, the storage racks where these masks are kept may also facilitate microorganism transmission. Our study aimed to isolate and identify microorganisms from infective skin lesions secondary to radiation dermatitis in head and neck cancer patients, as well as from the TMs and storage racks, and to evaluate the antibiotic resistance profiles of the isolated microorganisms. The study included 71 locally advanced head and neck cancer patients who underwent radiotherapy between August 2022 and November 2023. Patients were monitored daily, and their skin evaluations were made according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Grade 2 and 3 radiodermatitis was observed in 29 of these 71 patients. Samples were collected using sterile swabs from the skin lesions on the head and neck area, the inner surfaces of the TM, and the storage rack from 29 patients. Samples were inoculated into enrichment and selective media. After the growing microorganisms were identified, antimicrobial susceptibility was evaluated using conventional methods and automated systems according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. At least one type of microorganism was isolated from the skin samples of infected patients, and double growth was detected in two patients. Among the samples, 2 were methicillin-resistant coagulase-negative Staphylococcus (MRCNS), 1 was methicillin-resistant Staphylococcus aureus (MRSA), 1 was Candida albicans (C. albicans), 15 were methicillin-sensitive coagulase-negative Staphylococcus (MSCNS), 1 was methicillin-sensitive Staphylococcus aureus (MSSA), 1 was Bacillus subspecies (Bacillus spp.) and 3 were Corynebacterium diphtheriae (C. diphtheriae). Coagulase-negative Staphylococcus strains were isolated from the skin of 14 of 19 patients with grade 2 radiation dermatitis, whereas CNS strains were isolated from only 2 of 10 patients with grade 3 radiation dermatitis. Among the gram-negative bacteria, 3 Pseudomonas aeruginosa (P. aeruginosa), 2 Enterobacter cloacae (E. cloacae), 1 Klebsiella pneumoniae (K. pneumoniae) and 1 Moraxella catarrhalis (M. catarrhalis) strain were isolated. Sixteen (55.1%) of the TMs used in 29 patients and 20 (68.9%) of the storage racks harbored microorganisms, including HAI agents and flora bacteria. Bacteria colonize TMs and storage racks where they are risk factors for secondary skin infections in radiation dermatitis lesions that develop on the skin of head and neck cancer patients. Decontamination procedures should be meticulously applied to surfaces such as TMs and their storage racks during the course of radiotherapy.

Examining properties influencing infectious microbe associations with surfaces of four different thermoplastic radiation therapy masks

BACKGROUND

Previous testing revealed that four different microbes applied to face-only masks from Civco, Klarity Medical, Orfit, and Qfix demonstrated variation in the number recovered from each mask type after a 1-hour contact time. In all cases, the Orfit mask demonstrated the largest number of recovered microbes suggesting a preference by tested microbes to create associations with this mask type.

METHODS

The current study evaluated three physiochemical features of these thermoplastic masks to determine why the Orfit mask encouraged greater microbial associations. Measurements including water contact angle (WCA), surface topography, and available contact area were determined for each mask type, where feasible.

RESULTS

The Orfit mask exhibited the greatest difference in each of the 3 evaluated characteristics. Overall, it showed decreased hydrophobicity, increased surface roughness, and increased surface contact area. The WCA of both Orfit (50.8°) and Klarity (95.6°) masks showed decreased hydrophobicity when compared to native PCL (129.97°).

CONCLUSION

The Orfit mask's decreased hydrophobicity, increased roughness, and larger surface contact area appears to have contributed to its ability to support a larger number of microbe associations. The decreased hydrophobicity and altered topography of both Klarity and Orfit masks may have been due to their additional antimicrobial coatings.