ABSTRACT
Monofilament fibre pads may offer an effective, less invasive method for managing biofilms in pressure injuries, but their clinical effectiveness in reducing bacteria and biofilms has not been fully evaluated. Although biofilm removal is recommended for wound management, less invasive methods applicable to daily care remain limited. Therefore, this study aimed to assess the effectiveness of monofilament fibre pads compared to gauze in reducing bacterial counts and biofilm burden in pressure injuries. This retrospective cohort study was conducted at a Japanese university hospital. Bacterial counts were measured before and after cleansing using a rapid bacterial quantification system, and biofilm reduction rates were calculated using a wound blotting technique that enables non‐invasive and quantitative evaluation of biofilms across the entire wound bed. Linear mixed‐effects models were applied to evaluate the association between cleansing materials and outcomes, adjusting for baseline bacterial counts or biofilm brightness and the DESIGN‐R2020 total score. Thirty‐four pressure injuries in 30 patients were analysed, with 27 wound cleansing procedures performed using gauze and 73 using fibre pads. Fibre pad use significantly reduced bacterial counts (β = 0.389, p = 0.011) and biofilm burden (β = 0.642, p = 0.003) compared with gauze. Sensitivity analyses confirmed that these associations were robust, particularly after adjusting for baseline bacterial counts and biofilm brightness. These findings demonstrate that monofilament fibre pads are effective in reducing bacterial counts and biofilm burden in pressure injuries. Their routine use may provide a practical and less invasive adjunct for routine wound cleansing or maintenance biofilm control by facilitating bacterial and biofilm reduction.
Keywords: biofilm, debridement, fibre pad, subclinical infection, wound cleansing
Abbreviations
- CFUs
colony‐forming units
- CI
confidence interval
- IQR
interquartile range
- LSM
least‐square mean
- SEM
scanning electron microscopy
1. Introduction
Hard‐to‐heal wounds, which are prone to delayed wound healing despite standard treatment, are a serious health problem. The severity of pressure injuries prolongs hospital stays and follow‐up care, resulting in increased economic burdens [1, 2]. Bacterial biofilms are among the most important factors contributing to delayed wound healing, causing subclinical infection and chronic inflammation [3]. Biofilms, composed of extracellular polysaccharides, protect bacteria from antibiotics and host immunity and continuously release planktonic bacteria, leading to persistent infection [4]. Therefore, appropriate assessment and removal of biofilms are recommended in an international guideline for pressure injuries [5].
The development of a wound blotting technique has enabled non‐invasive visualisation and quantification of biofilms on wound surfaces in research and clinical settings [6, 7]. Although invasive debridement procedures such as sharp and ultrasonic debridement can effectively remove biofilms [8, 9], they cannot be performed frequently in routine clinical practise because of patient condition, pain, bleeding risk and staffing constraints. Moreover, wound biofilms can rapidly re‐establish after debridement and regain antibiotic resistance. Therefore, effective biofilm control during routine wound cleansing is essential. In contrast, routine wound cleansing using gauze and cleanser, which is commonly used in clinical practise, is often insufficient for biofilm removal. Wound care, including cleansing, is performed by nurses as well as other healthcare professionals and, in some settings, by patients or their caregivers. Furthermore, the frequency of wound cleansing is tailored to wound conditions such as exudate volume and wound status. Therefore, there is a clinical need for biofilm removal methods that are effective, less invasive and feasible for routine wound management.
Monofilament fibre pads have attracted attention as they can be used for daily wound cleansing in clinical settings. The European Wound Management Association recommends their use as part of debridement strategies [10]. Fibre pads effectively remove necrotic tissue, reducing pain and are less traumatic compared with conventional methods [11, 12, 13, 14]. However, no clinical studies have evaluated their efficacy in biofilm removal compared to standard gauze wound cleansing. Although some in vitro and ex vivo model studies have demonstrated biofilm removal by fibre pads [14, 15, 16, 17], their clinical effectiveness in pressure injuries remains unclear.
We hypothesized that wound cleansing using monofilament fibre pads would be more effective than gauze in removing bacteria and biofilms from pressure injuries. To address this hypothesis, we compared the bacteria and biofilm removal efficacy of monofilament fibre pads with gauze in a clinical setting.
2. Materials and Methods
2.1. Study Design
We conducted a retrospective cohort study as monofilament fibre pads are already routinely used in clinical practise for biofilm‐positive wounds. The study was conducted in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology checklist.
2.2. Setting and Participants
Hospitalised patients who routinely consulted the pressure injury team at a Japanese university hospital between November 2022 and July 2025 were screened for eligibility. The inclusion criterion was a pressure injury requiring wound cleansing using a fibre pad at least once. Pressure injuries without bacterial count measurements and biofilm assessment using the wound blotting method were excluded.
2.3. Wound Cleansing
Wound cleansing was performed by wound ostomy and continence nurses or a dermatologist using a cleanser with either sterile gauze (Hakujuji Co. Ltd., Tokyo, Japan) or a fibre pad (Wound Cloth, Gunze Medical Limited, Osaka, Japan). The fibre pad, consisting of densely packed monofilament fibres, has a soft, fleecy wound contact surface (Figure 1). Each pad was cut into quarters for use. The duration and frequency of wiping varied depending on the wound characteristics, for example, wound size and depth, and cleansing material (gauze or fibre pads). The choice of cleansing material was determined by care timing and supply availability.
FIGURE 1.
Structure of the monofilament fibre pad. The monofilament fibre pad measures 8.5 × 8.5 cm and contains a high density of monofilament fibres. The soft, fleecy side was used for wound cleansing.
2.4. Bacterial Count Measurement
Bacterial counts on wound surfaces were measured before and after cleansing using a rapid bacterial quantification system (Bacteria Counter, Panasonic Healthcare Co. Ltd., Tokyo, Japan). This system enables rapid bedside quantification of bacterial load and was routinely used in clinical practise at the study site, allowing retrospective analysis of real‐world data. The device quantifies bacterial load based on the dielectrophoretic impedance measurement method and has been shown to yield bacterial counts highly correlated with conventional swab culture results in oral cavity samples, supporting its validity [18]. In addition, inter‐rater and intra‐rater reliability have been demonstrated in pressure injury assessments [19, 20].
The longest axis of the pressure injuries was swabbed with a sterilised cotton‐tipped applicator, which was then immersed in a saline bottle and placed in the device. The measurable range was 1.0 × 105 to 1.0 × 108 colony‐forming units (CFUs)/mL. The log reduction in bacterial count was calculated as follows: log10(bacterial count before cleansing) − log10(bacterial counts after cleansing).
2.5. Wound Blotting for Biofilm Detection
Biofilm detection before and after cleansing was performed using the CC STEPS system (Saraya Co. Ltd., Osaka, Japan). This wound blotting method allows non‐invasive, semi‐quantitative assessment of biofilm presence across the wound surface and has been applied in previous clinical studies to evaluate biofilm burden and treatment response [7, 9]. Although it does not provide species‐level identification, it enables repeated, whole‐wound assessment without tissue injury, which is suitable for clinical cleansing studies. This method was selected because it allows bedside and repeated evaluation of biofilm burden, which is difficult to achieve with invasive tissue‐based analyses.
A 5 × 5 cm nitrocellulose membrane (Bio‐Rad Laboratories Inc., Hercules, CA) was applied to the wound bed for 10 s and then immersed in a pre‐treatment solution for 30 s, a staining solution for 30 s, and finally a destaining solution for 1 min. The stained membranes were scanned for image analysis (COMBO film scanner; Kenko Tokina Co. Ltd., Tokyo, Japan), and biofilm qualification was performed as described previously [9]. Colour correction was conducted using GIMP software (GNU Image Manipulation Program, version 2.10). Images were converted to grayscale, inverted and analysed using ImageJ software (National Institutes of Health, Bethesda, MD) to determine the average biofilm brightness, which ranged from 0 to 255, with higher values indicating greater biofilm accumulation.
The biofilm reduction rate was calculated using the following formula: (brightness before cleansing−brightness after cleansing)/brightness before cleansing×100 (%). Higher values indicate greater biofilm removal efficiency.
2.6. Study Variables and Measurements
Participant characteristics included age, sex and blood test results (albumin, haemoglobin and C‐reactive protein levels). Pressure injury characteristics included wound location, wound area and DESIGN‐R2020 total score, which assesses seven parameters (depth, exudate, size, inflammation/infection, granulation, necrotic tissue and pocket) [21, 22]. Higher DESIGN‐R2020 total scores indicate greater pressure injury severity. Wound area was measured using ImageJ software (National Institutes of Health) based on calibrated wound photographs.
2.7. Statistical Analyses
Continuous variables are summarised as median (inter‐quartile range [IQR]), whereas categorical variables as express as count (%). Group comparisons of continuous variables (e.g., DESIGN‐R2020 total score and wound area) were performed using the Wilcoxon rank‐sum test, whereas categorical variables (e.g., DESIGN‐R2020 categories) were compared using the Fisher exact test.
The biofilm reduction rate and bacterial log reduction were compared between gauze and fibre pad cleansing using the Wilcoxon rank‐sum test. A linear mixed‐effects model was used to account for wounds treated with both cleansing materials. Fixed effects included cleansing material (gauze or fibre pad), baseline bacterial count (for bacterial analysis) or baseline biofilm brightness (for biofilm analysis) and DESIGN‐R2020 total score, whereas pressure injury ID was treated as a random effect. To evaluate the robustness of the findings, sensitivity analyses were conducted using linear mixed‐effects models with different adjustment settings: (1) without adjustment, (2) adjusted for a single variable (baseline value or DESIGN‐R2020 score) and (3) adjusted for both variables (primary model). Least‐square mean (LSM) values were estimated for each group.
As this was a retrospective cohort study with a fixed sample size, we performed a post hoc power analysis using Monte Carlo simulation (10,000 iterations) for the Wilcoxon rank‐sum test with the wmwpow R package [23] to evaluate whether the sample size was sufficient. Assuming normal distributions based on previously reported biofilm reduction rates from a similar study [9] (control: mean = 38.9, SD ≈40.81; treatment: mean = 65.2, SD ≈27.93), the empirical power with 27 control subjects and 73 treatment subjects was 87.1% (two‐sided test, α = 0.05), indicating that the study had adequate statistical power to detect the observed effect.
A p‐value of < 0.05 was considered statistically significant, and all analyses were performed using R (version 4.2.2; R Foundation for Statistical Computing, Vienna, Austria).
2.8. Ethical Considerations
This study was approved by the Ethics Committee of the Graduate School of Medicine, The University of Tokyo (3757‐(11)) and conducted in accordance with the principles of the Declaration of Helsinki. All the participants were provided with the opportunity to opt out of the study.
3. Results
3.1. Participant Characteristics
Figure 2 shows the study flowchart. A total of 34 pressure injuries in 30 patients were included in the analysis. Among them, 27 wound cleansings were performed using gauze and 73 using fibre pads. The patients' characteristics are summarised in Table 1. The median patient age was 68 years (IQR: 58–78.2), and 17 patients (56.7%) were men. Among the 34 pressure injuries, 16 were located on the sacrum.
FIGURE 2.
Study flowchart of wound cleansing.
TABLE 1.
Patient characteristics.
| Participant characteristic | Median or number | IQR or % |
|---|---|---|
| Patients (n = 30) | ||
| Age (year) | 68 | 58–78.2 |
| Sex (male) | 17 | 56.7 |
| Blood test result | ||
| Albumin (g/dL) | 2.2 | 1.8–3.0 |
| Haemoglobin (g/dL) | 9.2 | 8.9–10.8 |
| C‐reactive protein (mg/dL) | 6.0 | 2.6–10.6 |
| Pressure injury characteristic (n = 34) | ||
| Location | ||
| Sacrum | 16 | 47.1 |
| Coccyx | 8 | 23.5 |
| Greater trochanter | 1 | 2.9 |
| Ilium | 1 | 2.9 |
| Others | 8 | 23.5 |
Abbreviation: IQR, interquartile range.
3.2. Pressure Injury Characteristics
Table 2 presents the pressure injury characteristics. The median DESIGN‐R2020 total scores were 21 (IQR: 18–23) and 21 (IQR: 18–34) in the gauze and fibre pad groups, respectively. The median wound areas were 5.4 cm2 (1.4–16.5) and 5.8 cm2 (2.4–12.0) in the respective groups. No significant differences were found in the total DESIGN‐R2020 total scores or wound areas between the groups. However, the gauze group had a significantly higher proportion of pressure injuries with an i0–1 inflammation/infection score than an I3C–9 score (p = 0.005).
TABLE 2.
Pressure injury characteristics.
| Characteristic | Gauze group (n = 27) | Fibre pad group (n = 73) | p |
|---|---|---|---|
| DESIGN‐R2020 total score | 21 (18–23) | 21 (18–34) | 0.700 |
| Depth | 0.340 | ||
| d2 | 4 (14.8%) | 9 (12.3%) | |
| D3 | 7 (25.9%) | 29 (39.7%) | |
| D4 | 2 (7.4%) | 5 (6.8%) | |
| D5 | 3 (11.1%) | 14 (19.2%) | |
| DU | 11 (40.7%) | 16 (21.9%) | |
| Exudate (e0–e3) | 22 (81.5%) | 69 (94.5%) | 0.057 |
| Exudate (E6) | 5 (18.5%) | 4 (5.5%) | |
| Size (s0–s12) | 27 (100.0%) | 73 (100.0%) | — |
| Size (S15) | 0 (0.0%) | 0 (0.0%) | |
| Inflammation/Infection (i0–1) | 23 (85.2%) | 40 (54.8%) | 0.005 |
| Inflammation/Infection (I3C–9) | 4 (14.8%) | 33 (45.2%) | |
| Granulation (g0–3) | 16 (59.3%) | 53 (72.6%) | 0.228 |
| Granulation (G4–6) | 11 (40.7%) | 20 (27.4%) | |
| Necrotic tissue (n0) | 2 (7.4%) | 11 (15.1%) | 0.505 |
| Necrotic tissue (N3–6) | 25 (92.6%) | 62 (84.9%) | |
| Pocket (p0) | 18 (66.7%) | 45 (61.6%) | 0.816 |
| Pocket (P6–24) | 9 (33.3%) | 28 (38.4%) | |
| Wound area (cm2) | 5.4 (1.4–16.5) | 5.8 (2.4–12.0) | 0.750 |
Note: Data are presented as median (interquartile range) or n (%). Continuous variables were compared using the Wilcoxon rank‐sum test, whereas categorical variables were compared using the Fisher exact test.
3.3. Bacterial Removal Effect of Wound Cleansing
Figure 3 shows the bacterial counts and their log reductions. Baseline bacterial counts were not significantly different between the gauze group (6.55, IQR: 6.08–6.95) and the fibre pad group (6.28, IQR: 5.73–6.88) (p = 0.323). The median log reductions for bacterial counts were 1.01 (IQR: 0.41–1.42) and 1.20 (IQR: 0.61–1.55) in the gauze and fibre pad groups, respectively, with no significant difference between the groups (p = 0.323).
FIGURE 3.
Bacterial counts and the log reduction of bacterial counts by wound cleansing. (A) Bacterial counts on the wound surface before and after cleansing. Red circles represent the gauze group, whereas blue circles represent the fibre pad group. (B) Log reduction of bacterial counts for the gauze and fibre pad groups. Circles represent individual pressure injuries, and horizontal bars indicate least‐squares means with 95% confidence interval estimated by a linear mixed‐effects model.
The linear mixed‐effects model (Table 3) showed that fibre pad use was significantly associated with a higher bacterial log reduction after adjusting for baseline bacterial counts and the DESIGN‐R2020 total score (β = 0.389, 95% confidence interval [CI]: 0.091–0.686, p = 0.011). Sensitivity analysis indicated that baseline bacterial counts were an important confounder; the β coefficients ranged from 0.284 to 0.389, and statistical significance was observed in the models adjusted for baseline bacterial counts (Supplementary Table S1). The LSM log reductions were 0.85 (95% CI: 0.67–1.04) and 1.14 (95% CI: 1.03–1.26) in the gauze and fibre pad groups, respectively.
TABLE 3.
Factors associated with the log reduction of bacterial counts.
| Standardised regression coefficient | Standard error | 95% confidence interval | p | |
|---|---|---|---|---|
| Use of fibre pads (ref: gauze) | 0.389 | 0.150 | 0.091–0.686 | 0.011 |
| Bacterial counts before wound cleansing (log10) | 0.785 | 0.067 | 0.651–0.918 | < 0.001 |
| DESIGN‐R2020 total score | −0.096 | 0.067 | −0.228–0.037 | 0.154 |
Note: A linear mixed‐effects model was used to evaluate the association of variables with a high log reduction of bacterial counts. The pressure injury ID was used as a random effect.
3.4. Biofilm and Bacteria Removal Effect by Wound Cleansing
Figure 4 shows the biofilm brightness and removal rates. Baseline biofilm brightness was significantly higher in the fibre pad group (16.3, IQR: 10.0–28.9) than in the gauze group (11.0, IQR: 7.1–19.0) (p = 0.037). The median biofilm removal rate was significantly higher in the fibre pad group than in the gauze group (40.9%, IQR: 25.2–56.2 versus 60.9%, IQR: 44.2–76.5; p = 0.001).
FIGURE 4.
Biofilm brightness and biofilm reduction rates by wound cleansing. (A) Biofilm brightness on the wound surface before and after cleansing, measured using wound blotting. Red circles represent the gauze group, whereas blue circles represent the fibre pad group. Brightness values range from 0 to 255, with higher values indicating greater biofilm accumulation based on grayscale image analysis. (B) Biofilm reduction rates for the gauze and fibre pad groups. Circles represent individual pressure injuries, and horizontal bars indicate least‐squares means with 95% confidence interval estimated by a linear mixed‐effects model.
The linear mixed‐effects model (Table 4) showed that fibre pad use was positively associated with a higher biofilm reduction rate after adjusting for baseline biofilm brightness and DESIGN‐R2020 total score (β = 0.642, 95% CI: 0.227–1.057, p = 0.003). Sensitivity analyses using models with different adjustment settings showed consistent results; the β coefficients ranged from 0.642 to 0.767 and remained statistically significant across all models (Supplementary Table 2). The LSM biofilm reduction rates were 40.7% (95% CI: 31.7–49.7) and 57.2% (95% CI: 51.7–62.6) in the gauze and fibre pad groups, respectively.
TABLE 4.
Factors associated with the biofilm removal rate.
| Standardised regression coefficient | Standard error | 95% confidence interval | p | |
|---|---|---|---|---|
| Use of fibre pads (ref: gauze) | 0.642 | 0.209 | 0.227–1.057 | 0.003 |
| Biofilm brightness before wound cleansing (%) | 0.364 | 0.104 | 0.156–0.571 | < 0.001 |
| DESIGN‐R2020 total score | −0.12 | 0.103 | −0.325–0.085 | 0.247 |
Note: A linear mixed‐effects model was used to evaluate the association between variables and a high biofilm reduction rate. The pressure injury ID was used as a random effect.
Representative wound blotting images before and after cleansing are shown in Supplementary Figure S1. Biofilm signals were markedly reduced in the fibre pad group compared to the gauze group, consistent with the quantitative findings.
4. Discussion
To our knowledge, this study is the first to demonstrate in the clinical setting that monofilament fibre pads are more effective than gauze in reducing bacterial counts and biofilm burden in pressure injuries. While previous studies have focused on the removal of necrotic tissue and slough [11, 12, 13, 14], few have quantitatively evaluated bacterial and biofilm removal during routine wound cleansing in hospitalised patients. Using a non‐invasive wound blotting method, we were able to assess biofilm reduction across the entire wound bed, providing new evidence for the clinical utility of fibre pads in wound biofilm and bacterial management.
Wound cleansing with fibre pads resulted in a significantly higher reduction in bacterial counts than that with gauze. This finding suggests that fibre pads have superior mechanical debridement properties, which is consistent with findings of in vitro studies reporting that fibre pads disrupt bacterial colonies more effectively than gauze after repeated wiping [15]. Because bacterial colonisation delays wound healing and increases infection risk [4], the higher bacterial reduction achieved with fibre pads highlights their clinical relevance in infection control. Moreover, the rapid bacterial quantification system used in the present study has a detection limit of 105 CFU/mL, which may underestimate reductions in wounds with low baseline counts. Therefore, adjusting for baseline bacterial counts was essential to accurately evaluate the independent effect of fibre pad use. Sensitivity analyses confirmed that baseline bacterial counts were an important confounder; the association between fibre pad use and bacterial reduction was significant only in models adjusted for baseline counts, indicating that the primary adjusted model sufficiently controlled for this confounding factor.
In addition to reducing bacteria, fibre pads were significantly more effective than gauze in removing wound biofilms. Biofilms were present in all wounds before cleansing, and the fibre pad group achieved a markedly higher biofilm removal rate than the gauze group, supporting our hypothesis. Although invasive methods such as scanning electron microscopy (SEM) are often used for biofilm assessment, they are unsuitable for clinical use due to their invasiveness and localised sampling. In contrast, the wound blotting method allowed for non‐invasive, quantitative assessment of biofilm reduction across the wound bed [24].
The biofilm removal rate observed in this study (median 60.9%) was slightly lower than that reported for ultrasonic debridement (65.2%) [9]. Wound cleansing using fibre pads may be a useful method for biofilm removal. The superior biofilm removal efficacy of fibre pads compared with gauze may be explained by their high‐density monofilament structure, which facilitates mechanical disruption and entrapment of slough and biofilms within the fibres, as shown in SEM observations [12, 15]. Although fibre pads tended to be selected for wounds with higher inflammation/infection scores, the linear mixed‐effects model confirmed that fibre pad use was independently associated with a higher biofilm removal rate after adjusting for baseline biofilm brightness and wound severity, indicating that the observed effect is robust. Sensitivity analyses further supported the robustness of this finding, as the β coefficients for fibre pad use remained statistically significant across all models with different adjustment settings.
The combined reduction of bacteria and biofilms is clinically relevant because biofilms serve as reservoirs that protect bacteria from antimicrobial agents and impede wound healing [4]. Thus, routine fibre pad use may contribute to improved wound healing by simultaneously reducing bacterial burden and disrupting biofilms. The degree of biofilm formation detected by wound blotting predicts the subsequent 30‐day and 90‐day wound healing outcomes [25, 26]. Although the present study did not evaluate long‐term outcomes, repeated wound cleansing with fibre pads may accelerate healing by reducing biofilm burden. Because biofilms on the wound bed can reform within a few days [27], frequent debridement is essential. Frequent debridement once a week or more promotes wound healing [28], but daily surgical or ultrasonic debridement is often impractical due to cost and staffing constraints. In this context, fibre pads, which are easy to use and less invasive, may serve as a useful adjunct for daily wound cleansing and/or maintenance debridement, rather than a replacement for formal debridement procedures.
This study has some limitations. First, the allocation of cleansing materials was not randomised and was influenced by clinical judgement, timing and material availability, resulting in potential selection bias and confounding by indication. In particular, fibre pads tended to be selected for wounds with higher levels of inflammation or suspected infection. To moderate this bias, we restricted the analysis to pressure injuries that had experienced both gauze and fibre pad cleansing and adjusted for wound severity using DESIGN‐R2020 scores and baseline bacterial and biofilm levels in a linear mixed‐effects model. However, detailed wound surface characteristics such as the extent of necrotic tissue or slough were not directly quantified and could not be included in the models. Because wound blotting reflects materials present on the wound surface, these unmeasured factors may have influenced the biofilm reduction results. Nevertheless, residual confounding cannot be completely excluded in this observational design. Importantly, despite these limitations, fibre pad use was associated with significantly greater reductions in bacterial load and biofilm burden, suggesting that the observed differences are unlikely to be solely explained by confounding. In addition, detailed parameters related to cleansing dose, such as cleansing duration, number of wipes and applied pressure, were not systematically recorded and therefore could not be adjusted for in the analysis. Variability in these factors may have influenced cleansing efficacy. Future studies using controlled ex vivo or in vivo models, in which cleansing dose parameters can be standardised and systematically manipulated, would be valuable to better isolate the mechanical effects of fibre pads on bacterial and biofilm removal.
Second, we did not investigate the relationship between fibre pad use and wound healing. Because patients at the university hospital had short hospital stays, long‐term follow‐up was not feasible. Moreover, daily wound cleansing practises by ward nurses were not standardised, making it difficult to assess the effect of continuous fibre pad use on wound healing. Prospective interventional studies controlling for cleansing time and frequency are required. Finally, pain associated with wound cleansing was not evaluated. Pain during wound care can lead to inadequate wound care because patients and healthcare providers may avoid thorough cleansing to reduce discomfort [29, 30, 31]. Pain associated with wound treatment also reduces patients' quality of life [32]. Although fibre pads reduce pain, this study did not assess this aspect; thus, their effectiveness in reducing pain and tissue damage remains unclear.
In conclusion, this study demonstrated that monofilament fibre pads are more effective than gauze in reducing bacterial counts and biofilm burden in pressure injuries. Fibre pads may be a practical and less invasive option to support routine wound cleansing and maintenance biofilm control.
Author Contributions
Chihiro Takizawa and Gojiro Nakagami contributed to the conception and study design. Chihiro Takizawa, Mari Abe, Sanae Sasaki, Akiko Kawasaki, Tomomi Miyake, Aya Kitamura and Gojiro Nakagami were involved in the data collection. Chihiro Takizawa, Qi Qin, Daijiro Haba and Gojiro Nakagami were involved in data analysis and data interpretation. Chihiro Takizawa, Qi Qin and Daijiro Haba drafted the original manuscript, and all authors critically revised the manuscript and approved the final manuscript. Hiromi Sanada and Gojiro Nakagami supervised the project.
Funding
This work was supported by Japan Society for the Promotion of Science (20H04010, 23H00547).
Ethics Statement
This study was approved by the Ethics Committee of the Graduate School of Medicine, University of Tokyo (3757‐(11)) and conducted in accordance with the principles of the Declaration of Helsinki. All the participants were provided with the opportunity to opt out of the study.
Conflicts of Interest
The authors have declare no conflicts of interest. However, the monofilament fibrefiber pads were developed in collaboration with Gunze Medical Limited.
Supporting information
Figure S1: Representative clinical images, wound blotting membranes and corresponding quantitative changes before and after wound cleansing. (A) Representative clinical wound images and corresponding wound blotting membranes before and after cleansing. Each row shows a representative case. The left column presents the clinical wound image, and the middle and right columns show the corresponding wound blotting membranes before and after cleansing for the same wound. (B) Changes in bacterial counts (log10) before and after cleansing for the representative cases shown in (A). The highlighted data points and connecting lines correspond to the representative wounds displayed above. (C) Biofilm reduction rates (%) before and after cleansing for the same representative cases. The highlighted data points correspond to the wound blotting images shown in (A), enabling direct comparison between qualitative images and quantitative measurements.
Table S1: Sensitivity analyses results for the association between fibre pad use and bacterial reduction.
Table S2: Sensitivity analyses results for the association between fibre pad use and biofilm reduction.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
References
- 1. Nakagami G., Morita K., Matsui H., Yasunaga H., Fushimi K., and Sanada H., “Association Between Pressure Injury Status and Hospital Discharge to Home: A Retrospective Observational Cohort Study Using a National Inpatient Database,” Ann Clin Epidemiol 2, no. 2 (2020): 38–50. [Google Scholar]
- 2. Demarré L., Van Lancker A., Van Hecke A., et al., “The Cost of Prevention and Treatment of Pressure Ulcers: A Systematic Review,” International Journal of Nursing Studies 52, no. 11 (2015): 1754–1774. [DOI] [PubMed] [Google Scholar]
- 3. James G. A., Swogger E., Wolcott R., et al., “Biofilms in Chronic Wounds,” Wound Repair and Regeneration 16, no. 1 (2008): 37–44. [DOI] [PubMed] [Google Scholar]
- 4. Edwards R. and Harding K. G., “Bacteria and Wound Healing,” Current Opinion in Infectious Diseases 17, no. 2 (2004): 91–96. [DOI] [PubMed] [Google Scholar]
- 5. European Pressure Ulcer Advisory Panel NPIAP and PPPIA , Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline. The International Guideline, ed. Haesler E. (EPUAP/NPIAP/PPPIA, 2019). [Google Scholar]
- 6. Minematsu T., Nakagami G., Yamamoto Y., et al., “Wound Blotting: A Convenient Biochemical Assessment Tool for Protein Components in Exudate of Chronic Wounds,” Wound Repair and Regeneration 21, no. 2 (2013): 329–334. [DOI] [PubMed] [Google Scholar]
- 7. Nakagami G., Schultz G., Gibson D. J., et al., “Biofilm Detection by Wound Blotting Can Predict Slough Development in Pressure Ulcers: A Prospective Observational Study,” Wound Repair and Regeneration 25, no. 1 (2017): 131–138. [DOI] [PubMed] [Google Scholar]
- 8. Nakagami G., Schultz G., Kitamura A., et al., “Rapid Detection of Biofilm by Wound Blotting Following Sharp Debridement of Chronic Pressure Ulcers Predicts Wound Healing: A Preliminary Study,” International Wound Journal 17, no. 1 (2020): 191–196. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Mori Y., Nakagami G., Kitamura A., et al., “Effectiveness of Biofilm‐Based Wound Care System on Wound Healing in Chronic Wounds,” Wound Repair and Regeneration 27, no. 5 (2019): 540–547. [DOI] [PubMed] [Google Scholar]
- 10. Strohal R., Dissemond J., Jordan O'Brien J., et al., “EWMA Document: Debridement. An Updated Overview and Clarification of the Principle Role of Debridement,” Journal of Wound Care 22, no. Supplementary1 (2013): S1–S52. [DOI] [PubMed] [Google Scholar]
- 11. Bahr S., Mustafi N., Hättig P., et al., “Clinical Efficacy of a New Monofilament Fibre‐Containing Wound Debridement Product,” Journal of Wound Care 20, no. 5 (2011): 242–248. [DOI] [PubMed] [Google Scholar]
- 12. Haemmerle G., Duelli H., Abel M., and Strohal R., “The Wound Debrider: A New Monofilament Fibre Technology,” British Journal of Nursing 20, no. 6 (2011): S35–S42. [DOI] [PubMed] [Google Scholar]
- 13. Gray D., Russell F., Cooper P., and Stringfellow S., “Assessing the Clinical Performance of a New Selective Mechanical Wound Debridement Product,” Wounds UK 7, no. 3 (2011): 42–46. [Google Scholar]
- 14. Schultz G. S., Woo K., Weir D., and Yang Q., “Effectiveness of a Monofilament Wound Debridement Pad at Removing Biofilm and Slough: Ex Vivo and Clinical Performance,” Journal of Wound Care 27, no. 2 (2018): 80–90. [DOI] [PubMed] [Google Scholar]
- 15. Wiegand C., Reddersen K., Abel M., et al., “Determination of the reduction of biofilm in vitro during wound cleansing using a monofilament debrider, a cleansing system with poloxamer, and conventional cotton gauze,” in Wounds UK Annual Conference in Harrogate, November, 2014.
- 16. Wiegand C., Reddersen K., Hipler U. C., Abel M., Ruth P., and Andriessen A., “In Vitro Evaluation of the Cleansing Effect of a Monofilament Fiber Debridement Pad Compared to Gauze Swabs,” Skin Pharmacology and Physiology 29, no. 6 (2016): 318–323. [DOI] [PubMed] [Google Scholar]
- 17. Wilkinson H. N., McBain A. J., Stephenson C., and Hardman M. J., “Comparing the Effectiveness of Polymer Debriding Devices Using a Porcine Wound Biofilm Model,” Advanced Wound Care 5, no. 11 (2016): 475–485. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18. Hamada R., Suehiro J., Nakano M., Kikutani T., and Konishi K., “Development of Rapid Oral Bacteria Detection Apparatus Based on Dielectrophoretic Impedance Measurement Method,” IET Nanobiotechnology 5, no. 2 (2011): 25–31. [DOI] [PubMed] [Google Scholar]
- 19. Nakagami G., Yoshida S., Matsumoto M., et al., “A New Objective Evaluation Method for PU Cleansing Using a Rapid Bacteria Counting System,” Journal of Wound Care 22, no. 5 (2013): 278–281. [DOI] [PubMed] [Google Scholar]
- 20. Nakagami G., Mori M., Yoshida M., et al., “Inter‐Rater and Intra‐Rater Reliability Outcomes of a Rapid Bacteria Counting System With Pressure Ulcer Samples,” Journal of Wound Care 26, no. Sup2 (2017): S27–S31. [DOI] [PubMed] [Google Scholar]
- 21. Matsui Y., Furue M., Sanada H., et al., “Development of the DESIGN‐R With an Observational Study: An Absolute Evaluation Tool for Monitoring Pressure Ulcer Wound Healing,” Wound Repair and Regeneration 19, no. 3 (2011): 309–315. [DOI] [PubMed] [Google Scholar]
- 22. Japanese Society of Pressure Ulcers , “Revised DESIGN‐R2020 Consensus Document,” 2020.
- 23. Mollan K. R., Trumble I. M., Reifeis S. A., et al., “Precise and Accurate Power of the Rank‐Sum Test for a Continuous Outcome,” Journal of Biopharmaceutical Statistics 30, no. 4 (2020): 639–648. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24. Wu Y. K., Cheng N. C., and Cheng C. M., “Biofilms in Chronic Wounds: Pathogenesis and Diagnosis,” Trends in Biotechnology 37, no. 5 (2019): 505–517. [DOI] [PubMed] [Google Scholar]
- 25. Wu Y. F., Lee T. Y., Liao W. T., Chuan H. H., Cheng N. C., and Cheng C. M., “Rapid Detection of Biofilm With Modified Alcian Blue Staining: In‐Vitro Protocol Improvement and Validation With Clinical Cases,” Wound Repair and Regeneration 28, no. 6 (2020): 834–843. [DOI] [PubMed] [Google Scholar]
- 26. Wu Y. F., Lin Y. C., Yang H. W., Cheng N. C., and Cheng C. M., “Point‐Of‐Care Wound Blotting With Alcian Blue Grading Versus Fluorescence Imaging for Biofilm Detection and Predicting 90‐Day Healing Outcomes,” Biomedicine 10, no. 5 (2022): 1200. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27. Wolcott R. D., Rumbaugh K. P., James G., et al., “Biofilm Maturity Studies Indicate Sharp Debridement Opens a Time‐ Dependent Therapeutic Window,” Journal of Wound Care 19, no. 8 (2010): 320–328. [DOI] [PubMed] [Google Scholar]
- 28. Wilcox J. R., Carter M. J., and Covington S., “Frequency of Debridements and Time to Heal: A Retrospective Cohort Study of 312 744 Wounds,” JAMA Dermatology 149, no. 9 (2013): 1050–1058. [DOI] [PubMed] [Google Scholar]
- 29. Stotts N. A., Puntillo K., Bonham Morris A., et al., “Wound Care Pain in Hospitalized Adult Patients,” Heart & Lung 33, no. 5 (2004): 321–332. [DOI] [PubMed] [Google Scholar]
- 30. Obilor H. N., Adejumo P. O., and Ilesanmi R. E., “Assessment of Patients' Wound‐Related Pain Experiences in University College Hospital, Ibadan, Nigeria,” International Wound Journal 13, no. 5 (2016): 697–704. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31. Gardner S. E., Blodgett N. P., Hillis S. L., et al., “HI‐TENS Reduces Moderate‐To‐Severe Pain Associated With Most Wound Care Procedures: A Pilot Study,” Biological Research for Nursing 16, no. 3 (2014): 310–319. [DOI] [PubMed] [Google Scholar]
- 32. Spilsbury K., Nelson A., Cullum N., Iglesias C., Nixon J., and Mason S., “Pressure Ulcers and Their Treatment and Effects on Quality of Life: Hospital Inpatient Perspectives,” Journal of Advanced Nursing 57, no. 5 (2007): 494–504. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Figure S1: Representative clinical images, wound blotting membranes and corresponding quantitative changes before and after wound cleansing. (A) Representative clinical wound images and corresponding wound blotting membranes before and after cleansing. Each row shows a representative case. The left column presents the clinical wound image, and the middle and right columns show the corresponding wound blotting membranes before and after cleansing for the same wound. (B) Changes in bacterial counts (log10) before and after cleansing for the representative cases shown in (A). The highlighted data points and connecting lines correspond to the representative wounds displayed above. (C) Biofilm reduction rates (%) before and after cleansing for the same representative cases. The highlighted data points correspond to the wound blotting images shown in (A), enabling direct comparison between qualitative images and quantitative measurements.
Table S1: Sensitivity analyses results for the association between fibre pad use and bacterial reduction.
Table S2: Sensitivity analyses results for the association between fibre pad use and biofilm reduction.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.