Abstract
Background
Critically ill patients in intensive care units (ICUs) are at risk for colonization and infection by carbapenem-resistant Acinetobacter baumannii (CRAB), a multidrug-resistant pathogen with high mortality. Despite the use of infection control bundles, CRAB often persists on environmental surfaces, posing ongoing challenges for containment. The potential impact of managing soft environmental reservoirs—such as pillow covers—remains underexplored. This study evaluated whether daily pillow cover replacement can reduce CRAB acquisition in a medical ICU (MICU).
Methods
A prospective intervention study was conducted in a 23-bed MICU at a tertiary hospital in Korea between August 2023 and July, 2024. Standard infection prevention and control (IPC) practices, including hand hygiene, cohort isolation, chlorhexidine bathing, and routine cleaning, were consistent throughout the study. Starting February 1, 2024, pillow covers were replaced regularly as an additional intervention. CRAB acquisition was defined as positive clinical cultures obtained > 48 h after admission. Incidence rates were compared between the pre- and post-intervention periods using Poisson regression and interrupted time series analyses.
Results
A total of 152 patients met the inclusion criteria (108 pre- and 44 post-intervention). In this study, 224 CRAB-positive clinical specimens were identified from 152 patients, and only the first isolate per patient was included in the incidence analysis. The mean age was 76 years; 59.9% were male, and the average MICU stay was 26 days. Sputum accounted for 76.8% of CRAB-positive specimens. Compliance with daily pillow cover replacement was 100%. Poisson regression revealed a significant reduction in CRAB incidence following the intervention, with a 3.92% weekly decrease (95% CI 0.10–7.69%; p = 0.045).
Conclusions
When integrated into existing IPC bundles, daily pillow-cover replacement may reduce CRAB cross-transmission in the MICU. This simple, low-cost intervention with high compliance offers a promising strategy for improving environmental hygiene and infection control in high-risk settings.
Keywords: Carbapenem-resistant Acinetobacter baumannii, Pillow cover replacement, Infection prevention and control, Intensive care unit
Introduction
Critically ill patients in intensive care units (ICUs) are highly susceptible to opportunistic infections and colonization by carbapenem-resistant Acinetobacter baumannii (CRAB), a pathogen that poses a significant threat due to its extensive drug resistance and high mortality rates [1–3]. The global increase in CRAB prevalence, particularly in ICUs, has been driven by its considerable ability to survive on dry surfaces for extended periods and its capacity for rapid environmental dissemination [1, 3–5]. This persistence enables CRAB to contaminate a wide range of surfaces and equipment within the patient care environment, including bed units, medical devices, and soft items such as pillow covers [4, 6–8].
CRAB is designated as a notifiable multidrug-resistant organism by the national surveillance system throughout South Korea, reflecting its public health importance. Recent ICU-based cohort data from South Korea reported CRAB colonization upon admission in 5.2% of patients, suggesting a substantial baseline burden in critically ill patients [9]. Furthermore, between 2020 and 2022, our hospital data demonstrated persistently elevated annual CRAB detection rates, ranging from 9.62 to 13.96 cases per 1,000 patients. These data indicate a high baseline burden of CRAB in the Korean healthcare setting.
Despite the implementation of various infection control bundles, including hand hygiene, contact precautions, patient isolation, and enhanced environmental cleaning, CRAB outbreaks remain difficult to control. This is largely due to the organism’s environmental resilience and the challenges in maintaining strict adherence to protocols in high-acuity settings [1, 4, 6, 10]. Environmental contamination has been consistently identified as a major factor of CRAB transmission. Furthermore, the ICU environment has been recognized as a persistent reservoir, facilitating cross-transmission between patients and healthcare workers [4, 6, 8]. Genomic investigations have shown that CRAB clusters can persist in bed units and be acquired by new patients even after routine cleaning [4].
While interventions such as terminal cleaning, use of disinfectants, and innovative approaches such as bacteriophage aerosols have shown some success in reducing the incidence of CRAB, the specific role of soft surface management, including daily replacement of pillow covers, remains underexplored [2, 10]. Pillow covers are in direct and prolonged contact with patients and may harbour multidrug-resistant organisms. Their regular replacement could represent a simple yet effective strategy to reduce environmental contamination and interrupt CRAB transmission chains [7, 11].
This study aimed to evaluate whether daily pillow cover replacement can reduce the acquisition of CRAB in a medical ICU (MICU) setting, addressing a critical gap in current infection prevention and control practices, and potentially informing future guidelines for managing multidrug-resistant organisms in high-risk hospital environments.
Methods
Study design and setting
This prospective before-and-after intervention study was conducted in a 23-bed MICU of a tertiary care hospital in Korea between August 2023 to July 2024. The study aimed to evaluate the effect of daily pillow cover replacement on the incidence of carbapenem-resistant Acinetobacter baumannii (CRAB) among critically ill adult patients. The pre-intervention period spanned August 2023 to January 2024 (27 weeks), and the intervention period extended from February 2024 to July 2024 (26 weeks). No major changes occurred in staffing, ICU structure, or patient population during both phases. This study was granted approval by the Institutional Review Board (IRB) (approval number: 2024AN0482) and continued until the conclusion of the study period.
Infection prevention and control measures
A comprehensive infection prevention and control (IPC) program was implemented during the study period. Hand hygiene was rigorously implemented in accordance with the WHO “Five Moments for Hand Hygiene,” requiring hand disinfection before and after patient contact, after exposure to bodily fluids or patient surroundings, and prior to aseptic procedures [12]. Contact precautions were maintained for patients colonized or infected with multidrug-resistant organisms, including CRAB, requiring strict hand hygiene and mandatory use of gloves and gowns, with immediate hand disinfection upon room exit.
The MICU includes four single isolation rooms; it is prioritized for patients requiring strict isolation, particularly those colonized or infected with carbapenem-resistant Enterobacterales (CRE), in accordance with institutional infection control policies. CRAB-positive patients were separated when isolation rooms were unavailable, otherwise, they were managed in open-bay areas with reinforced infection prevention measures and dedicated medical equipment, whenever possible. In addition, all patients received daily bathing with 2% chlorhexidine gluconate (CHG) as part of standard nursing care to reduce colonization by multidrug-resistant organisms [12]. These IPC practices remained unchanged during the pre-intervention and intervention periods.
The environmental service personnel followed a standardized cleaning sequence designed to prevent cross-contamination. Cleaning was performed in a top-to-bottom and clean-to-dirty manner, with high-touch surfaces cleaned prior to lower-touch areas and floors. When indicated, separate cleaning materials were used for individual patient zones to minimize cross-transmission. Disinfection primarily utilized wipes containing alkylbenzyl dimethyl ammonium chloride, ethanol, and dodecyl dimethyl ammonium compounds. In addition, diluted solutions of dodecyl dimethyl ammonium chloride, polyhexamethylene biguanide hydrochloride, and chlorhexidine gluconate were prepared and applied according to institutional environmental disinfection protocols. Terminal cleaning was performed upon patient discharge or transfer using the same disinfectants with enhanced attention given to high-touch areas. Although formal quantitative audits were not routinely conducted, compliance was monitored by the Infection Prevention and Control team through the ongoing surveillance of the incidence of multidrug-resistant organism infections and periodic environmental assessments. In addition, comprehensive unit-wide environmental disinfection was conducted from July 1 to 3, 2024, as part of the routine annual maintenance, including deep cleaning of floors, medical equipment, and common areas.
Nursing care practices and linen management in the ICU
Prior to the implementation of the intervention, structured education was provided to MICU nursing staff and support personnel to reinforce standardized linen handling and infection prevention practices [12]. Under routine nursing care protocols, complete bed linen, including bed sheets, pillowcases, and blankets, were replaced at ICU admission and when visibly soiled or clinically indicated. Routine daily linen changes were not standard practice.
The bed frame, mattress surfaces, and surrounding high-touch areas were cleaned and disinfected according to established environmental protocols independent of linen changes. No additional disinfection of the bed or pillow core was introduced as part of the intervention, and the pillow was not routinely disinfected unless it was visibly contaminated.
On February 1, 2024, daily pillowcase replacement was introduced as an additional nursing intervention. Each morning, the assigned day-duty nurse replaced the pillowcase as part of the routine bed care. The frequency of replacement of other bed linens remained unchanged from the pre-intervention period. Due to staffing and operational constraints, daily replacement of all bed linens was not feasible; therefore, the routine linen replacement schedule was continued. The intervention was integrated into the existing nursing workflow without additional staffing, shift restructuring, and measures introducing new infection control or quality improvement. Other components of patient care and infection prevention practices remained unchanged throughout the study period.
Intervention: daily pillow cover replacement
The MICU implemented a standardized protocol for daily pillow cover replacement, beginning on February 1, 2024. Trained nursing staff replaced each patient’s pillow cover every morning as a part of routine bed care. The pillow covers were processed using the hospital’s standardized linen reprocessing system. Used pillow covers were collected in designated laundry bags and transported to an external medical-grade laundry facility. Reprocessing followed institutional infection control standards, including high-temperature washing (≥ 70 °C) with detergent and thermal disinfection, followed by complete drying before redistribution [12]. No changes in laundering temperature, chemical agents, or processing standards occurred during the study period. In addition, no changes in microbiological testing policies, culture indications, specimen processing procedures, organism identification methods, or antimicrobial susceptibility testing protocols between the study periods were observed.
A structured checklist was used to monitor compliance with the daily pillow-cover replacement protocol. Each morning, charge nurses supervised the replacement process and, with designated nursing staff, verified that the pillow covers were replaced in all occupied beds. The completion of replacement for each bed was recorded using a standardized daily checklist. The completed checklists were subsequently reviewed by the infection control and prevention team to verify adherence and calculate compliance rates. Weekly CRAB incidence was calculated as the number of hospital-onset cases per 1,000 patient-days.
Participants and outcome definition
The study included patients aged ≥ 19 years who were admitted to the MICU during the study period and who had at least one microbiological culture obtained > 48 h after admission. Hospital-onset CRAB was defined as the first clinical culture yielding CRAB more than 48 h after ICU admission [1, 2]. A previously documented negative CRAB culture on admission was not required for case classification.
Universal active surveillance cultures, specifically targeting CRAB, were not performed upon MICU admission. Instead, the baseline CRAB status at admission was determined based on clinical cultures obtained within 48 h before or after MICU admission. These cultures were performed according to clinical indications, and most critically ill patients underwent microbiological testing around the time of MICU admission. Patients with documented CRAB colonization or infection within 48 h of MICU admission were considered to have community- or previously-acquired CRAB and were excluded from all analytical comparisons. Importantly, the daily pillow cover replacement protocol was implemented universally for all MICU patients during the intervention period, regardless of the baseline CRAB status. Clinical specimens included sputum, blood, urine, abscess fluid, cerebrospinal fluid, ascitic fluid, skin/soft tissue samples, and other clinically indicated specimens.
Data collection
Demographic data, length of stay in the MICU, culture results, and mortality outcomes were prospectively collected. Weekly MICU census data were also obtained to calculate patient days for incidence rate estimation. All data were cross-validated using the hospital’s electronic medical records system.
Statistical analysis
Weekly CRAB incidence was calculated as the number of newly identified hospital-onset cases per 1,000 patient-days. To evaluate the effect of the intervention, an interrupted time-series analysis was conducted using segmented Poisson regression. Weekly CRAB cases were modeled with the log of patient days included as an offset term to account for variations in the population at risk. The model adjusted for baseline incidence level and pre-intervention temporal trend and estimated both the immediate level change and the change in slope following implementation of the intervention. The results are reported as incidence rate ratios (IRRs) with 95% confidence intervals. Statistical significance was defined as a two-sided p-value < 0.05.
Results
Patient characteristics
A total of 152 patients met the inclusion criteria during the study period, with 108 and 44 admitted during the pre- and post-intervention periods, respectively (Table 1). The median age of the cohort was 76 years (interquartile range, 67–83 years), and 59.9% of the patients were male. The baseline demographic characteristics, including age and sex, were similar between the groups. However, the median MICU length of stay was significantly longer in the post-intervention than that in the pre-intervention period (33 vs. 24 days, p = 0.032). The median hospital length of stay, which included both MICU and general ward stays, was numerically longer in the post-intervention period (52 vs. 36 days); however, this difference was not statistically significant (p = 0.056). Similarly, mortality was lower in the post-intervention period (50.0% vs. 63.9%) but did not reach statistical significance (p = 0.113).
Table 1.
Baseline demographics and clinical specimens for CRAB isolation in patients in the MICU during the study period
| Patients, n | Total | Pre-intervention (27 weeks) | Post-intervention (26 weeks) | p-Value |
|---|---|---|---|---|
| 152 | 108 | 44 | ||
| Age, years, median (IQR) | 76 (67–83) | 75 (67–83) | 77 (64–84) | 0.526 |
| Male, n (%) | 91 (59.9) | 64 (70.3) | 27 (61.4) | 0.810 |
|
ICU stay, days median (IQR) |
26 (14–44) | 24 (13–37) | 33 (19–54) | 0.032 |
|
Hospital stay, days median (IQR) |
39 (24–69) | 36 (24–62) | 52 (21–88) | 0.056 |
| Mortality, n (%) | 91 (59.9) | 69 (63.9) | 22 (50.0) | 0.113 |
CRAB-positive clinical specimens
In total, 224 CRAB-positive clinical specimens were identified throughout the study: 159 in the pre-intervention period and 65 in the post-intervention period (Table 2). Sputum was the predominant specimen type, accounting for 76.8% of all CRAB isolates, followed by blood (12.9%), urine (5.4%), abscess fluid (2.7%), and other sources including cerebrospinal fluid, skin, and ascitic fluid (2.2%). The distribution of the specimen types was comparable between the two periods. Since multiple clinical specimens could be obtained from a single patient during hospitalization, the number of specimens exceeded the number of individual patients. Only the first CRAB isolate identified > 48 h after MICU admission was included per patient for incidence estimation and interrupted time-series analysis.
Table 2.
Distribution of CRAB-positive specimens
| Specimen type | Total specimens (n = 224) | Pre-intervention (n = 159) | Post-intervention (n = 65) | p-Value |
|---|---|---|---|---|
| Abscess, n (%) | 6 (2.7) | 4 (2.5) | 2 (3.1) | 0.813 |
| Blood, n (%) | 29 (12.9) | 22 (13.8) | 7 (10.8) | 0.535 |
| Sputum, n (%) | 172 (76.8) | 123 (77.4) | 49 (75.4) | 0.751 |
| Urine, n (%) | 12 (5.4) | 7 (4.4) | 5 (7.7) | 0.321 |
| Others1, n (%) | 5 (2.2) | 3 (1.9) | 2 (3.1) | 0.584 |
1Other: CSF, sore site, skin, and ascites
The percentages in Table 2are calculated based on the total number of CRAB-positive specimens. Multiple specimens may have been obtained from a single patient. Incidence analyses were conducted at the patient level, using only the first CRAB isolate per patient.
Compliance with infection prevention measures
Compliance with daily pillow cover replacement during the intervention period was 100%. Other infection prevention measures, including adherence to hand hygiene, use of contact isolation precautions, daily chlorhexidine bathing, and routine environmental cleaning, remained consistently high throughout the study period (Table 3). Hand hygiene compliance was assessed through routine direct observation audits conducted by the infection control team, in accordance with institutional monitoring protocols. Adherence to daily chlorhexidine gluconate (CHG) bathing was monitored by nursing documentation review. Contact precautions and personal protective equipment (PPE) use were implemented following institutional policy; however, quantitative compliance data for PPE use were not recorded separately during the study period. The average CHG bathing compliance rate was 85% before February 2024, increased to 96% from February 20 to May 19, and remained at 93% between May 20 and July 31.
Table 3.
Infection prevention measures and compliance rates during the study period
| Infection prevention measure | Pre-intervention | Post-intervention | |
|---|---|---|---|
| Hand hygiene compliance1, % (mean) | 76% | 76.5% | |
| Contact precautions adherence2 |
Implemented by institutional policy |
Implemented by institutional policy |
|
| Daily CHG bathing compliance1, % (mean) | 85% | 94% | |
| Pillow cover replacement compliance, % | Not applicable | 100% | |
| Routine environmental cleaning | Standardized protocol | Standardized protocol |
1Compliance rates were based on routine infection control monitoring
2The use of personal protective equipment was implemented in accordance with institutional contact precaution protocols; however, quantitative compliance data were not systematically recorded during the study period. CHG Chlorhexidine gluconate
Effect of daily pillow cover replacement on CRAB acquisition
During the pre-intervention period, 4,055 patient-days were recorded compared to 3,657 patient-days during the intervention period. Incidence rates were calculated per 1,000 patient-days to account for differences in exposure times between periods. The mean observed incidence was 5.89 cases per 1,000 patient-days during the pre-intervention period and 2.5 cases per 1,000 patient-days during the intervention period.
Poisson regression analysis assessing the impact of the intervention on CRAB acquisition demonstrated a statistically significant reduction in incidence rates during the intervention period (Table 4). After adjusting for weekly patient-days, the intervention was associated with a 3.92% weekly decrease in CRAB incidence (IRR, 0.961; 95% CI, 0.923–0.999; p = 0.045). The immediate level change following implementation showed a non-significant decrease (IRR, 0.642; p = 0.105), whereas the pre-intervention trend showed no significant change over time (IRR, 1.005; p = 0.592) (Fig. 1). These findings indicate a gradual but significant decline in CRAB acquisition associated with daily pillow cover replacement protocols.
Table 4.
Incidence Rate Ratio and associated percent changes for an interrupted time series analysis model of CRAB incidence in the MICU during the study periods
| Regression coefficient (95% CI) | p-value1 | IRR (95% CI) | Percent change2 (95% CI) | ||
|---|---|---|---|---|---|
| CRAB prevalence in clinical cultures | |||||
| Intercept (β0) | -3.317 (-3.654 to -3.000) | < 0.005 | 0.036 (0.026–0.050) | -96.38 (-97.41 to -95.02) | |
| Pre-intervention slope (β1) | 0.005 (-0.014 to 0.025) | 0.592 | 1.005 (0.986–1.025) | 0.50 (-1.39 to 2.53) | |
| Intervention level change (β2) | -0.443 (-0.990 to 0.082) | 0.105 | 0.642 (0.372–1.086) | -35.80 (-62.85 to 8.55) | |
| Intervention slope change (β3) | -0.040 (-0.080 to -0.001) | 0.045 | 0.961 (0.923–0.999) | -3.92 (-7.69 to -0.10) | |
1Interrupted time series with a segmented Poisson regression model
2(IRR-1)×100
Fig. 1.
Interrupted time-series analysis of CRAB incidence in MICU patients after pillow cover replacement. Weekly observed incidence of hospital-onset CRAB per 1,000 patient-days before and after implementation of daily pillow cover replacement. Data points represent the raw observed incidence, and the solid line represents the fitted value from the interrupted time-series regression model
Overall impact
Despite longer MICU stays among patients during the intervention period, the introduction of daily pillow cover replacement was associated with a significant reduction in CRAB acquisition rates. These results suggest that daily pillow cover replacement may be associated with a reduced in hospital-onset CRAB acquisition in the MICU.
Discussion
This study demonstrated that daily pillow cover replacement implemented within an existing IPC bundle was associated with a significant reduction in CRAB acquisition in the MICU. We identified a gradual weekly decline in CRAB incidence following the intervention (IRR, 0.961) using interrupted time-series (ITS) analysis, thereby, supporting the hypothesis that targeted management of soft environmental reservoirs may contribute to the reduction in endemic CRAB transmission [13, 14]. Given that sputum accounted for most of the CRAB-positive specimens in our cohort, the intervention was biologically plausible as pillow surfaces frequently contact respiratory secretions and skin flora.
CRAB contamination in ICUs has been shown to be driven by the organism’s persistence on both wet and dry surfaces and its capacity to form environmental reservoirs that facilitate continuous cross-transmission [15–20]. Although environmental hygiene efforts have traditionally focused on high-touch hard surfaces, soft surfaces such as linens, patient gowns, and pillow covers are increasingly recognized as underappreciated vectors [20–22]. A recent scoping review on hospital textile management further highlighted that healthcare textiles may serve as reservoirs for microbial contamination. In addition, structured textile replacement and decontamination strategies have the potential to reduce bacterial burden, although robust patient-level outcome data remain limited [23]. Whole-genome sequencing studies have traced CRAB transmission directly to environmental reservoirs surrounding the patient bed unit, including fabrics and soft equipment [18, 24]. These findings are consistent with our results and underscore the importance of expanding the scope of environmental hygiene to include textiles.
Pillow covers represent a unique environmental niche due to their near-continuous contact with patients and healthcare workers, and frequent exposure to respiratory droplets, perspiration, and skin debris. Previous studies have shown that Acinetobacter species can survive for prolonged periods on hospital fabric, including cotton and polyester, facilitating repeated contamination and transmission [20, 25]. Although enhanced environmental cleaning protocols have been shown to reduce the CRAB burden [10, 22], few studies have evaluated daily textile replacement as a focused intervention. This study addresses this gap by providing empirical evidence that consistent high-compliance pillow cover replacement may significantly reduce the risk of CRAB acquisition.
The effectiveness of the intervention likely reflects the high adherence rate (100%) and its integration into a broader multimodal IPC framework. Multimodal bundles, incorporating environmental cleaning, hand hygiene, contact precautions, staff education, and chlorhexidine bathing, have been shown to achieve superior CRAB control compared with single interventions [13, 15, 17, 26, 27]. Notably, daily chlorhexidine bathing compliance in our unit ranged from 85% to 96%, reinforcing the established understanding that bundle effectiveness depends heavily on consistent implementation [14, 28, 29]. Therefore, our findings support the recommendation that pillow cover replacement should be considered as an additional modular component within existing bundles rather than as a standalone solution.
The ITS analysis strengthened the methodological rigor of the study. This quasi-experimental approach distinguishes true intervention effects from underlying temporal trends and secular changes, thereby, offering advantages over simple pre- and post-comparisons [10, 14, 15, 30]. The lack of an immediate level change coupled with a significant negative slope change suggests an accumulating effect consistent with the progressive reduction in environmental contamination rather than the abrupt interruption of transmission pathways. Similar temporal patterns have been documented in previous ITS-based CRAB intervention studies [26, 30], thereby validating the analytical strategy employed.
A comprehensive unit-wide environmental disinfection was conducted from July 1 to 3, 2024, as part of routine annual maintenance and was not triggered by an outbreak investigation, documented cross-transmission event, or epidemiological surge. No comparable unit-wide disinfection was performed immediately prior to the pre-intervention period. Although this deep cleaning occurred during the intervention phase and could theoretically have reduced the environmental reservoirs of CRAB, the interrupted time-series analysis did not demonstrate a statistically significant immediate level change; instead, it showed a gradual decline in incidence over time. This temporal pattern suggests that the observed reduction is unlikely to be solely attributable to a single environmental cleaning event. Nevertheless, the independent contribution of deep cleaning cannot be completely separated from that of the pillow cover replacement intervention.
Previous reports of mortality rates among critically ill patients with CRAB infection in the ICU frequently exceed 50%, reflecting the severe baseline clinical condition of this population [31, 32]. In our study, mortality exceeded 50% during both pre-intervention and intervention periods, suggesting that both cohorts represented a similar high-risk critically ill population. Although formal severity indices were not incorporated into the analysis, the consistently high mortality rate observed in both periods implies that the study population comprised patients with substantial baseline clinical severity. However, the extent to which the observed mortality patterns influenced CRAB incidence could not be explicitly determined in the present analysis. Therefore, further studies incorporating standardized severity adjustments and patient-level analyses are warranted to better elucidate the relationship between mortality patterns and CRAB acquisition.
Despite these strengths, this study had several limitations. First, as a single-center, quasi-experimental before-and-after study, the generalizability of our findings may be limited, particularly for ICUs with different baseline CRAB burdens, patient case mix, or environmental cleaning practices. Furthermore, the absence of randomization and potential residual confounding factors inherent to interrupted time-series designs may limit causal inferences. Additionally, the intervention was implemented within a primarily nursing-led framework without formal interdisciplinary coordination, possibly limiting the generalizability to institutions with different organizational or case delivery structures. Second, although national and institutional surveillance data were presented to provide an epidemiological context, ICU-specific long-term incidence trends were not formally modeled within the interrupted time-series framework, possibly limiting full adjustment for underlying secular trends. Third, detailed severity indices, such as the simplified acute physiology score II or acute physiology and chronic health evaluation II scores, were not systematically analyzed. Although previous studies have reported a high ICU CRAB mortality, differences in baseline illness severity between the study periods may have contributed to the observed variation in mortality rates. Future studies incorporating standardized severity adjustments are warranted to better elucidate this relationship. Fourth, our study focused specifically on CRAB and did not systematically assess the intervention’s effects on other multidrug-resistant organisms, which may limit the evaluation of its broader applicability. Asymptomatic colonization may have remained under-detected because CRAB-specific active surveillance was not performed at ICU admission, and microbiological testing was based on clinical indications rather than universal screening. Fifth, although formal microbiological testing policies remained unchanged, unmeasured differences in clinical sampling intensity between periods could not be entirely excluded. Differences in MICU length of stay, hospital length of stay, and mortality between study periods may reflect variations in patient case-mix or illness severity. Although the interrupted time-series analysis accounts for temporal trends at the population level, it does not adjust for individual-level clinical variables. Therefore, residual confounding factors related to differences in baseline severity or hospitalization patterns could not be excluded. Future studies incorporating standardized severity indices and multivariate modelling are warranted to further elucidate these associations.
Nevertheless, this study has substantial clinical and operational implications. Daily pillow cover replacement is a low-cost, scalable, and sustainable practice that can be integrated smoothly into routine nursing workflows without disrupting ICU operations or requiring specialized disinfectants or equipment. This intervention is far more feasible for long-term applications than intensive environmental strategies, such as terminal disinfection with chlorine, disinfectant switching, or wall decontamination [24]. Importantly, as CRAB continues to genetically diversify and demonstrate high levels of drug resistance worldwide [4], expanding environmental prevention measures is becoming increasingly essential.
Future research should include multicentre evaluations, cost-effectiveness analyses, and environmental sampling studies to directly quantify the reduction in textile contamination. Whole-genome sequencing could further clarify whether pillow cover replacement alters CRAB transmission networks. Studies comparing replacement frequencies (daily vs. every other day) and assessing the effects on other multidrug-resistant organisms are also warranted.
Conclusion
This study provides real-world evidence that daily pillow cover replacement is a practical, low-cost, feasible, and potentially impactful addition to multimodal IPC strategies for controlling CRAB in MICUs. By addressing soft textiles, a traditionally overlooked environmental reservoir, this approach supports a more comprehensive, systems-based model of CRAB transmission prevention and may contribute to sustainable reductions in ICU-acquired CRAB infections.
Acknowledgements
Not applicable.
Abbreviations
- CRAB
Carbapenem resistant Acinetobacter baumannii
- MICU
Medical intensive care unit
- ICU
Intensive care unit
- IPC
Infection prevention and control
- CHG
Chlorhexidine gluconate
- IRR
Incidence rate ratios
- ITS
interrupted time series
Author contributions
J.W.S performed the data analysis, writing, and drafting of the manuscript. J.W.S performed the conceptualization, methodology, validation, and scientific oversight. K.S.Y conducted the statistical analyses. J.Y.K performed the data management and drafting of the manuscript. Y.K.Y performed the data management and scientific oversight.
Funding
This research was supported by grants from the Government-wide R&D Fund for Infectious Disease Research, funded by the Ministry of the Interior and Safety of the Republic of Korea (grant number 20015024) and the Ministry of Science and ICT, Korea, under the ICT Creative Consilience Program (IITP-2023-2020-0-01819) supervised by the Institute for Information and Communications Technology Planning and Evaluation. The funding had no role in the study design, data collection, data analysis, decision to publish, or manuscript preparation.
Data availability
No datasets were generated or analysed during the current study.
Declarations
Ethics approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Ben-Chetrit E, Wiener-Well Y, Lesho E, et al. An intervention to control an ICU outbreak of carbapenem-resistant Acinetobacter baumannii: Long-term impact for the ICU and hospital. Crit Care. 2018;22(1):1–10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Ho Y-H, Tseng C-C, Wang L-S, et al. Application of bacteriophage-containing aerosol against nosocomial transmission of carbapenem-resistant Acinetobacter baumannii in an intensive care unit. PLoS ONE. 2016;11(12):e0168380. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Ababneh Q, Aldaken N, Jaradat Z, et al. Predominance of extensively-drug resistant Acinetobacter baumannii carrying bla OXA-23 in Jordanian patients admitted to the intensive care units. PLoS ONE. 2025;20(2):e0317798. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Doughty EL, Liu H, Moran RA, et al. Endemicity and diversification of carbapenem-resistant Acinetobacter baumannii in an intensive care unit. Lancet Reg Health West Pac. 2023;37(100780):100780. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Jawad A, Seifert H, Snelling AM, et al. Survival of Acinetobacter baumannii on dry surfaces: Comparison of outbreak and sporadic isolates. J Clin Microbiol. 1998;36(7):1938–41. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Perez S, Innes GK, Maroya, et al. Increase in Hospital-Acquired Carbapenem-Resistant Acinetobacter baumannii Infection and Colonization in an Acute Care Hospital During a Surge in COVID-19 Admissions -New Jersey, February-July 2020. MMWR Morb Mortal Wkly Rep. 2020;69(48):1827–31. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Weernink A, Severin WP, Tjernberg I, et al. Pillows, an unexpected source of Acinetobacter. J Hosp Infect. 1995;29(3):189–99. [DOI] [PubMed] [Google Scholar]
- 8.Baleivanualala SC, Matanitobua S, Samisoni Y, et al. Environmental contamination with carbapenem resistant Acinetobacter baumannii in healthcare settings in Fiji: a potential source of infection. Front Cell Infect Microbiol. 2024;14:1429443. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Kim YA, Park YS, Lee SS, et al. Colonization prevalence and risk factor analysis of carbapenem-resistantAcinetobacter baumanniiin an intensive care unit without outbreaks. Korean J Healthc-Assoc Infect Control Prev. 2019;24(2):81. [Google Scholar]
- 10.Tomczyk S, Zanichelli V, Grayson ML, et al. Control of carbapenem-resistant enterobacteriaceae, acinetobacter baumannii, and pseudomonas aeruginosa in healthcare facilities: A systematic review and reanalysis of quasi-experimental studies. Clin Infect Dis. 2019;68(5):873–84. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Lee ALH, Leung ECM, Wong BWH, et al. Clean clothes or dirty clothes? Outbreak investigation of carbapenem-resistant Acinetobacter baumannii related to laundry contamination through multilocus sequence typing (MLST). Infect Control Hosp Epidemiol. 2023;44(8):1274–80. [DOI] [PubMed] [Google Scholar]
- 12.World Health Organization. Guidelines on core components of infection prevention and control programmes at the national and acute health care facility level. Geneva: World Health Organization. 2016 [cited 2025 Nov 30]. Available from: https://www.who.int/publications/i/item/9789241549929 [PubMed]
- 13.Meschiari M, Lòpez-Lozano J-M, Di Pilato V, et al. A five-component infection control bundle to permanently eliminate a carbapenem-resistant Acinetobacter baumannii spreading in an intensive care unit. Antimicrob Resist Infect Control. 2021;10(1):123. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Zhao B, Wang Q, Lu J, et al. Enhanced infection prevention and control interventions decreased carbapenem-resistant Acinetobacter baumannii colonization and infection in an intensive care unit: a 4-year retrospective study. J Hosp Infect. 2025;167:9–15. [DOI] [PubMed] [Google Scholar]
- 15.Kawamura H, Arimura S, Murata N et al. 1450. Managing a Multidrug-resistant Acinetobacter baumannii outbreak in the ICU: A successful KAIZEN program using process indicators for antimicrobial stewardship, hand hygiene, and standardization. Open Forum Infect Dis. 2023;10(Supplement_2):ofad500.1287.
- 16.Kelemen J, Sztermen M, Dakos EK, et al. Complex infection-control measures with disinfectant switch help the successful early control of carbapenem-resistant Acinetobacter baumannii outbreak in intensive care unit. Antibiot (Basel). 2024;13(9):869. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Valencia-Martín R, Gonzalez-Galan V, Alvarez-Marín R, et al. A multimodal intervention program to control a long-term Acinetobacter baumannii endemic in a tertiary care hospital. Antimicrob Resist Infect Control. 2019;8(1):199. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Zingg S, Kuster S, von Rotz M, et al. Outbreak with OXA-23-producing Acinetobacter baumannii in a COVID-19 ICU cohort: unraveling routes of transmission. Antimicrob Resist Infect Control. 2024;13(1):127. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Lerner AO, Abu-Hanna J, Carmeli Y, et al. Environmental contamination by carbapenem-resistant Acinetobacter baumannii: The effects of room type and cleaning methods. Infect Control Hosp Epidemiol. 2019;41(2):166–71. [DOI] [PubMed] [Google Scholar]
- 20.Nygren E, Gonzales Strömberg L, Logenius J, et al. Potential sources of contamination on textiles and hard surfaces identified as high-touch sites near the patient environment. PLoS ONE. 2023;18(7):e0287855. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Thatrimontrichai A, Pannaraj PS, Janjindamai W, et al. Intervention to reduce carbapenem-resistant Acinetobacter baumannii in a neonatal intensive care unit. Infect Control Hosp Epidemiol. 2020;41(6):710–5. [DOI] [PubMed] [Google Scholar]
- 22.Casini B, Righi A, De Feo N, et al. Improving cleaning and disinfection of high-touch surfaces in intensive care during carbapenem-resistant Acinetobacter baumannii endemo-epidemic situations. Int J Environ Res Public Health. 2018;15(10):2305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Caliaro A, Pontirolli A, Canzan F, et al. The effect of textiles and their management on healthcare-associated infections: A scoping review. Am J Infect Control. 2026;54(2):210–21. [DOI] [PubMed] [Google Scholar]
- 24.Dickstein Y, Eluk O, Warman S, et al. Wall painting following terminal cleaning with a chlorine solution as part of an intervention to control an outbreak of carbapenem-resistant Acinetobacter baumannii in a neurosurgical intensive care unit in Israel. J Infect Chemother. 2021;27(10):1423–8. [DOI] [PubMed] [Google Scholar]
- 25.Ma LL, Wei Y-Y, Li J, et al. Clinical study of antibacterial medical textiles containing polyhydroxyalkanoate oligomers for reduction of hospital-acquired infections. J Hosp Infect. 2024;149:144–54. [DOI] [PubMed] [Google Scholar]
- 26.Hong J, Jang OJ, Bak MH, et al. Management of carbapenem-resistant Acinetobacter baumannii epidemic in an intensive care unit using multifaceted intervention strategy. Korean J Intern Med. 2018;33(5):1000–7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Suhaimi NA, Hamzah HC, Ishak M, et al. Reducing the incidence of Hospital-Acquired Multidrug- Resistant Acinetobacter Baumannii (HA-MDRAB) in the intensive care unit (ICU) of a teaching hospital through multimodal environmental cleaning strategies. Antimicrob Steward Healthc Epidemiol. 2025;5(S1):s13–13. [Google Scholar]
- 28.Climo MW, Yokoe DS, Warren DK, et al. Effect of Daily Chlorhexidine Bathing on Hospital-Acquired Infection. N Engl J Med. 2013;368(6):533–42. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29.Huang W, Qiao F, Cai L, et al. Effect of daily chlorhexidine bathing on reducing infections caused by multidrug-resistant organisms in intensive care unit patients: A semiexperimental study with parallel controls. J Evid Based Med. 2023;16(1):32–8. [DOI] [PubMed] [Google Scholar]
- 30.Schechner V, Cohen A, Carmeli Y. Tailoring interventions for control of endemic carbapenem-resistant Acinetobacter baumannii: An interrupted time series analysis. Open Forum Infect Dis. 2024;11(6):ofae301. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Boutzoukas A, Doi Y. The global epidemiology of carbapenem-resistant Acinetobacter baumannii. JAC Antimicrob Resist. 2025;7(4):dlaf134. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Karakonstantis S, Kritsotakis EI, Tziolos R-N, et al. Mortality due to carbapenem-resistant Acinetobacter baumannii bacteraemia: a 5-year cohort study in intensive care patients. Clin Microbiol Infect. 2025;31(6):1033–9. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
No datasets were generated or analysed during the current study.