Nasal and skin microbiomes are associated with disease severity in paediatric atopic dermatitis.

BACKGROUND: Alterations of the skin microbiome have been associated with atopic dermatitis (AD) and its severity. The nasal microbiome in relation to AD severity is less well studied. OBJECTIVES: We aimed to characterize the nasal and skin microbiomes in children with AD in relation to disease severity. In addition, we explored the differences and correlations between the nasal and skin communities. METHODS: We characterized the microbial composition of 90 nasal and 108 lesional skin samples cross-sectionally from patients with AD, using 16S-rRNA sequencing. In addition, a quantitative polymerase chain reaction was performed for Staphylococcus aureus and Staphylococcus epidermidis on the skin samples, and AD severity was estimated using the self-administered Eczema Area and Severity Index. RESULTS: We found an association between the microbial composition and AD severity in both the nose and skin samples (R2  = 2·6%; P = 0·017 and R2  = 7·0%; P = 0·004), strongly driven by staphylococci. However, other species also contributed, such as Moraxella in the nose. Skin lesions were positive for S. aureus in 50% of the children, and the presence and the load of S. aureus were not associated with AD severity. Although the nose and skin harbour distinct microbial communities (n = 48 paired samples; P < 0·001), we found that correlations exist between species in the nose and (other) species on the skin. CONCLUSIONS: Our results indicate that both the nasal and the skin microbiomes are associated with AD severity in children and that, next to staphylococci, other species contribute to this association.

Older ovarian cancer survivors report lower long-term health-related quality of life than younger survivors: A study from the population-based profiles registry.

OBJECTIVE: To assess long-term differences in health-related quality of life (HRQoL) of older ovarian cancer survivors compared to both an age-matched normative population and to younger survivors. In addition, the differential effect of chemotherapy on HRQoL between older and younger survivors was compared. METHODS: Ovarian cancer survivors (n = 348) diagnosed between 2000 and 2010, as registered by the Dutch population-based Eindhoven Cancer Registry, were invited to complete the EORTC QLQ-C30 HRQoL questionnaire in 2012. HRQoL outcomes of survivors were compared with an age-matched normative population and older survivors (≥70 years) were compared with younger survivors. RESULTS: The questionnaire was returned by 191 ovarian cancer survivors (55%), 31% were aged ≥70 years (n = 59). Compared to the normative population, survivors ≥70 years scored lower on global health status and all functioning subscales except emotional functioning, and they reported more symptoms. Survivors aged <70 years only reported worse physical and cognitive functioning in comparison with the normative population. Most differences were of medium to small clinical relevance. Age appeared to moderate the effect of chemotherapy on HRQoL. Older survivors who had received chemotherapy experienced better physical functioning and less pain and insomnia while the opposite was found in younger survivors. CONCLUSION: In comparison with an age-matched normative population, older ovarian cancer survivors report lower HRQoL scores than younger survivors. As this represents a selection of long-term survivors, future research should focus on the trajectory of HRQoL from diagnosis throughout treatment and follow-up to identify which factors are related to worse HRQoL in the entire older ovarian cancer population and whether timely interventions are able to improve HRQoL.

Presence of gastro-intestinal symptoms in ovarian cancer patients during survivorship: a cross-sectional study from the PROFILES registry.

OBJECTIVE: To assess the association between gastro-intestinal (GI) symptoms and health-related quality of life (HRQoL) in ovarian cancer (OC) survivors. METHODS: Women diagnosed with OC between 2000 and 2010 as registered in the Netherlands cancer registry (n = 348), received a questionnaire on socio-demographic characteristics, HRQoL (EORTC-QLQ-C30), ovarian cancer-specific symptoms including GI (EORTC-QLQ OV28), and psychological distress (HADS). Data collection took place in 2012. RESULTS: Of 348 women diagnosed with ovarian cancer, 191 (55%) responded. Of all participants, 69% were eligible for analysis (n = 131). In 25% of all women, high level GI symptoms occurred (n = 33). In 23% of all women, recurrence of OC occurred (n = 30). Regression analysis showed that presence of high levels of GI symptoms during survivorship was associated with lower functioning on all HRQoL domains (except for emotional functioning), more symptoms, and higher levels of distress. QoL was negatively affected in those who had few and high levels of GI symptoms. QoL of those with recurrent disease was worse than those without recurrent disease. CONCLUSION: A substantial proportion of OC survivors experience GI symptoms, regardless of the recurrence of disease. Health care professionals should be aware of GI symptoms during survivorship in order to refer their patients for supportive care interventions to reduce symptoms or help survivors to cope. Further research should examine the cause of GI symptoms during OC survivorship among those with non-recurrent disease.

Association between information provision and supportive care needs among ovarian cancer survivors: A cross-sectional study from the PROFILES registry.

OBJECTIVE: To examine the association between satisfaction with perceived information provision during diagnosis and treatment and supportive care needs in ovarian cancer survivors. METHODS: In 2012, women (n = 348) diagnosed with ovarian cancer, as registered between 2000 and 2010 in the Netherlands Cancer Registry, received a questionnaire including questions on the perceived level of, and satisfaction with, information received (EORTC QLQ-INFO25) and supportive care needs (Cancer Survivors' Unmet Needs Measure). RESULTS: Of 348 women, 191 (55%) responded. Of all participants, 35% were not satisfied (n = 65) with the perceived amount of information received. Participants who were satisfied with the amount of information reported significantly higher levels of perceived information on disease, medical tests, treatment, and other services. Patients not satisfied with information provision had a higher total number of needs and a higher number of unmet needs than women satisfied with information provision. Multivariable linear regression analysis showed that satisfaction with information provision was negatively associated with the total number of unmet needs (ß = -0.20, P = .03) after adjustment for potential confounding clinical and sociodemographic factors. CONCLUSION: Ovarian cancer survivors satisfied with the information provision during treatment reported fewer unmet needs during survivorship. Optimization of information provision for ovarian cancer patients during initial diagnosis and treatment may contribute to a decrease in unmet needs during survivorship.

Incidence of surgical site infections cannot be derived reliably from point prevalence survey data in Dutch hospitals.

Thorough studies on whether point prevalence surveys of healthcare-associated infections (HAIs) can be used to reliably estimate incidence of surgical site infections (SSIs) are scarce. We examined this topic using surveillance data of 58 hospitals that participated in two Dutch national surveillances; HAI prevalence and SSI incidence surveillance, respectively. First, we simulated daily prevalences of SSIs from incidence data. Subsequently, Rhame & Sudderth's formula was used to estimate SSI incidence from prevalence. Finally, we developed random-effects models to predict SSI incidence from prevalence and other relevant variables. The prevalences simulated from incidence data indicated that daily prevalence varied greatly. Incidences calculated with Rhame & Sudderth's formula often had values below zero, due to the large number of SSIs occurring post-discharge. Excluding these SSIs, still resulted in poor correlation between calculated and observed incidence. The two models best predicting total incidence and incidence during initial hospital stay both performed poorly (proportion of explained variance of 0·25 and 0·10, respectively). In conclusion, incidence of SSIs cannot be reliably estimated from point prevalence data in Dutch hospitals by any of the applied methods. We therefore conclude that prevalence surveys are not a useful measure to give reliable insight into incidence of SSIs.

What Is the Origin of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Clonal Complex 398 Isolates from Humans without Livestock Contact? An Epidemiological and Genetic Analysis.

Fifteen percent of all methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 398 (CC398) human carriers detected in The Netherlands had not been in direct contact with pigs or veal calves. To ensure low MRSA prevalence, it is important to investigate the likely origin of this MRSA of unknown origin (MUO). Recently, it was shown that CC398 strains originating from humans and animals differ in the presence of specific mobile genetic elements (MGEs). We hypothesized that determining these specific MGEs in MUO isolates and comparing them with a set of CC398 isolates of various known origin might provide clues to their origin. MUO CC398 isolates were compared to MRSA CC398 isolates obtained from humans with known risk factors, a MRSA CC398 outbreak isolate, livestock associated (LA) MRSA CC398 isolates from pigs, horses, chickens, and veal calves, and five methicillin-susceptible Staphylococcus aureus (MSSA) CC398 isolates of known human origin. All strains were spa typed, and the presence or absence of, scn, chp, φ3 int, φ6 int, φ7 int, rep7, rep27, and cadDX was determined by PCRs. The MRSA CC398 in humans, MUO, or MRSA of known origin (MKO) resembled MRSA CC398 as found in pigs and not MSSA CC398 as found in humans. The distinct human MSSA CC398 spa type, t571, was not present among our MRSA CC398 strains; MRSA CC398 was tetracycline resistant and carried no φ3 bacteriophage with scn and chp. We showed by simple PCR means that human MUO CC398 carriers carried MRSA from livestock origin, suggestive of indirect transmission. Although the exact transmission route remains unknown, direct human-to-human transmission remains a possibility as well.

Dutch guideline on the laboratory detection of methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) has rapidly emerged worldwide, affecting both healthcare and community settings, and intensive livestock industry. The efficient control of MRSA strongly depends on its adequate laboratory detection. This guideline provides recommendations on the appropriate use of currently available diagnostic laboratory methods for the timely and accurate detection of MRSA in patients and healthcare workers. Herewith, it aims to standardise and improve the diagnostic laboratory procedures that are used for the detection of MRSA in Dutch medical microbiology laboratories.

A search strategy for detecting duodenoscope-associated infections: a retrospective observational study.

BACKGROUND: Duodenoscope-associated infections (DAIs) are exogenous infections resulting from the use of contaminated duodenoscopes. Though numerous outbreaks of DAI have involved multidrug-resistant micro-organisms (MDROs), outbreaks involving non-MDROs are also likely to occur. Detection challenges arise as these infections often resolve before culture or because causative strains are not retained for comparison with duodenoscope strains. AIM: To identify and analyse DAIs spanning a seven-year period in a tertiary care medical centre. METHODS: This was a retrospective observational study. Duodenoscope cultures positive for gastrointestinal flora between March 2015 and September 2022 were paired with duodenoscope usage data to identify patients exposed to contaminated duodenoscopes. Analysis encompassed patients treated after a positive duodenoscope culture and those treated within the interval from a negative to a positive culture. Patient identification numbers were cross-referenced with a clinical culture database to identify patients developing infections with matching micro-organisms within one year of their procedure. A 'pair' was established upon a species-level match between duodenoscope and patient cultures. Pairs were further analysed via antibiogram comparison, and by whole-genome sequencing (WGS) to determine genetic relatedness. FINDINGS: Sixty-eight pairs were identified; of these, 21 exhibited matching antibiograms which underwent WGS, uncovering two genetically closely related pairs categorized as DAIs. Infection onset occurred up to two months post procedure. Both causative agents were non-MDROs. CONCLUSION: This study provides crucial insights into DAIs caused by non-MDROs and it highlights the challenge of DAI recognition in daily practice. Importantly, the delayed manifestation of the described DAIs suggests a current underestimation of DAI risk.

Good performance of the SpectraCellRA system for typing of methicillin-resistant Staphylococcus aureus isolates.

Typing of methicillin-resistant Staphylococcus aureus (MRSA) remains necessary in order to assess whether transmission of MRSA occurred and to what extent infection prevention measures need to be taken. Raman spectroscopy (SpectraCellRA [SCRA]; RiverD International, Rotterdam, The Netherlands) is a recently developed tool for bacterial typing. In this study, the performance (typeability, discriminatory power, reproducibility, workflow, and costs) of the SCRA system was evaluated for typing of MRSA strains isolated from patients and patients' household members who were infected with or colonized by MRSA. We analyzed a well-documented collection of 113 MRSA strains collected from 54 households. The epidemiological relationship between the MRSA strains within one household was used as the gold standard. Pulsed-field gel electrophoresis (PFGE) was used for discrepancy analysis. The results of SCRA analysis on the strain level corresponded with epidemiological data for 108 of 113 strains, a concordance of 95.6%. When analyzed at the household level, the results of SCRA were correct for 49 out of 54 households, a concordance of 90.7%. Concordance on the strain level with epidemiological data for PFGE was 93.6% (103/110 isolates typed). Concordance on the household level with epidemiological data for PFGE was 93.5% (49/53 households analyzed). With PFGE regarded as the reference standard, the conclusions reached with Raman spectroscopy were identical to those reached with PFGE in 100 of 105 cases (95.2%). The reproducibility of SCRA was found to be 100%. We conclude that the SpectraCellRA system is a fast, easy-to-use, and highly reproducible typing platform for outbreak analysis that can compete with the currently used typing techniques.

Use of surgical-site infection rates to rank hospital performance across several types of surgery.

BACKGROUND: Comparing and ranking hospitals based on health outcomes is becoming increasingly popular, although case-mix differences between hospitals and random variation are known to distort interpretation. The aim of this study was to explore whether surgical-site infection (SSI) rates are suitable for comparing hospitals, taking into account case-mix differences and random variation. METHODS: Data from the national surveillance network in the Netherlands, on the eight most frequently registered types of surgery for the year 2009, were used to calculate SSI rates. The variation in SSI rate between hospitals was estimated with multivariable fixed- and random-effects logistic regression models to account for random variation and case mix. 'Rankability' (as the reliability of ranking) of the SSI rates was calculated by relating within-hospital variation to between-hospital variation. RESULTS: Thirty-four hospitals reported on 13 629 patients, with overall SSI rates per surgical procedure varying between 0 and 15·1 per cent. Statistically significant differences in SSI rate between hospitals were found for colonic resection, caesarean section and for all operations combined. Rankability was 80 per cent for colonic resection but 0 per cent for caesarean section. Rankability was 8 per cent in all operations combined, as the differences in SSI rates were explained mainly by case mix. CONCLUSION: When comparing SSI rates in all operations, differences between hospitals were explained by case mix. For individual types of surgery, case mix varied less between hospitals, and differences were explained largely by random variation. Although SSI rates may be used for monitoring quality improvement within hospitals, they should not be used for ranking hospitals.

Higher yield in duodenoscope cultures collected with addition of neutralizing agent.

AIM: Microbiological cultures are the gold standard in the monitoring of duodenoscope reprocessing. However, many different sampling and culturing techniques are used, making it difficult to compare results. The latest Centers for Disease Control and Prevention protocol advises the use of a neutralizer to deactivate any remaining disinfectants in the samples. This study compared culturing results of duodenoscope samples collected with and without addition of a neutralizer. METHODS: Six duodenoscopes were soiled with gut bacteria in a non-clinical experimental setting and reprocessed afterwards. Samples of the tip and working channel were collected immediately after decontamination or after drying. Dey-Engley (DE) broth was added as a neutralizer to the samples of four duodenoscopes; samples for the other two duodenoscopes were collected without the addition of DE broth. RESULTS: Post-decontamination cultures were significantly more likely to be positive for growth of the applied micro-organisms in the group of samples with DE broth (88.1% vs 20.2%; P<0.0001). Post-drying samples were significantly more likely to be positive in the group of samples without DE broth (75.7% vs 33.4%; P<0.001). CONCLUSION: The addition of DE broth to samples collected from wet duodenoscopes increases the yield of those cultures. Remaining disinfectants in wet duodenoscopes can lead to false-negative results. This can be overcome by adding a neutralizer, such as DE broth, to the samples. The higher yield after drying in the group without neutralizer could be due to biofilm formation in these two duodenoscopes, but this was not investigated. Standardization of the sampling method can help to compare both clinical and study results regarding duodenoscope contamination.

Validity of self-reported compliance and behavioural determinants of observed compliance: an application of the COM-B hand hygiene questionnaire in nine Dutch hospitals.

BACKGROUND: Hand hygiene compliance (HHC) can be influenced by behavioural determinants, but knowledge on this remains scarce. The Capability, Opportunity, Motivation-Behaviour (COM-B) hand hygiene questionnaire was developed by Lydon et al. to gain insight into self-reported behavioural determinants and self-reported HHC. AIMS: To determine the validity of self-reported HHC using the COM-B questionnaire; and investigate the influence of self-reported behavioural determinants on observed HHC, taking environmental determinants into account. METHODS: This was a cross-sectional study, from September to November 2019, in nine hospitals in the Netherlands. Healthcare workers (HCWs) completed the COM-B questionnaire, and direct hand hygiene observations were performed. In addition, information on environmental determinants (workload, ward category, hospital type and ward infrastructure) was collected. Validity of self-reported HHC was determined using the intraclass correlation coefficient (ICC). Univariable and multi-variable regression analyses were performed to investigate the relationship between behavioural and environmental determinants and observed HHC. FINDINGS: The ICC showed no association between self-reported HHC and observed HHC [0.04, 95% CI -0.14 to 0.21]. In univariable regression analyses, ward category and the opportunity and motivation subscales were significantly associated with observed HHC. In multi-variable regression analysis, only ward category and the motivation subscale remained significant. CONCLUSION: Self-reported HHC is not a valid substitute for direct hand hygiene observations. Motivation (behavioural determinant) was significantly associated with HCC, while almost none of the environmental determinants had an effect on observed HHC. In further development of hand hygiene interventions, increasing the intrinsic motivation of HCWs should receive extra attention.

Vermamoeba vermiformis resides in water-based heater-cooler units and can enhance Mycobacterium chimaera survival after chlorine exposure.

BACKGROUND: Mycobacterium chimaera colonizes water-based heater-cooler units (HCUs), from which it can spread to patients during surgery. Vermamoeba vermiformis is a free-living waterborne amoeba, which was consistently present within HCUs. AIM: To determine whether these amoebae can be involved in the persistent presence of M. chimaera. METHODS: An in-vitro disinfection model. FINDINGS: Increased survival of M. chimaera was observed after chlorine exposure in the presence of V. vermiformis. Confocal microscopy demonstrated the intracellular presence of M. chimaera in V. vermiformis. CONCLUSION: In this way, V. vermiformis can contribute to the persistent presence of M. chimaera in HCUs. Cleaning and disinfection protocols should take this phenomenon into account.

Compliance with a novel hand hygiene protocol tailored to non-sterile healthcare workers in the operating theatre.

BACKGROUND: Observing hand hygiene compliance (HHC) among non-sterile healthcare workers (HCWs) in the operating theatre (OT) is challenging as there are no tailored protocols or observation tools. AIM: To develop and test a hand hygiene protocol tailored to non-sterile HCWs in the OT. METHODS: In this prospective observational study, nine hospitals in the Rotterdam-Rijnmond region provided input on a draft protocol on hand hygiene in the OT, resulting in a new consensus protocol for the region. An observation tool based on the protocol was developed and tested. HHC rates with 95% confidence intervals (CI) were calculated by type of hospital and type of HCW. FINDINGS: The protocol has three sections: (1) written general hand hygiene rules; (2) written hand hygiene rules specific for anaesthesia and surgery; and (3) visual representation of the OT, divided into four hand hygiene areas. Hand hygiene should be applied when changing area. Average HHC of 48.0% (95% CI 45.2-61.2%) was observed in OTs across all hospitals. HHC was highest in the two specialized hospitals (64.0%, 95% CI 30.6-89.8%; 76.7%, 95% CI 62.8-84.5%) and lowest in the academic teaching hospital (23.1%, 95% CI 0.0-45.8%). In terms of type of HCW, HHC was lowest among anaesthesiologists (31.6%, 95% CI 19.2-62.4%) and highest among OT assistants (57.4%, 95% CI 50.1-78.2%). CONCLUSION: This uniform way of observing HHC in the OT enables evaluation of the effectiveness of interventions in the OT and facilitates friendly competition. In the Rotterdam-Rijnmond region, HHC in the OT was below 50%; this needs to be addressed, particularly in teaching hospitals and among physicians.

Frequency of microbiologically correct antibiotic therapy increased by infectious disease consultations and microbiological results.

In a prospective observational study of bacteremic patients we ascertained the influence of different parts of culture results on the correctness of empirical antibiotic therapy. Ninety-three bacteremic patients requiring antibiotic treatment were included. Patients who had consultations with an infectious disease consultation service before they became bacteremic received microbiologically correct empirical antibiotic therapy more often than those who did not have such consultations (75% versus 53%; P = 0.03). As a direct result of Gram staining, 92% of all patients received microbiologically correct antibiotic therapy.

Environmental sampling of innate hospital surfaces: a survey of current practices and the need for guidelines.

BACKGROUND: Surfaces in healthcare facilities can act as reservoirs of infection. Currently, no standardized protocol on when and how to sample hospital surfaces exists. AIM: A web-based questionnaire was devised to gain insight into current sampling practices and was distributed by email to a targeted infection prevention and control (IPC) audience. METHODS: The survey consisted of 26 questions on sample collection and processing for a number of healthcare relevant bacterial species. FINDINGS: The majority of respondents were clinical microbiologists or IPC practitioners, and 57.3% were from either the Netherlands, the United Kingdom, or Ireland. Respondents had high self-reported knowledge, but this was not consistent with response to certain questions. There was no consensus on sample sites, either within or between countries. Indirect sampling methods were preferred for all target microorganisms, and cotton and flocked swabs were the most popular methods. CONCLUSION: The results of our survey highlight the inconsistencies in environmental sampling between and within countries, and the need for guidance and consensus.

Impact of sink design on bacterial transmission from hospital sink drains to the surrounding sink environment tested using a fluorescent marker.

In hospitals, sinks act as reservoirs for bacterial pathogens. To assess the extent of splashing, fluorescein dye was added to four hospital sinks previously involved in pathogen dispersal to the environment and/or transmission to patients, and one sink that was not. Applying dye to the p-trap or tailpiece did not result in any fluorescent droplets outside of the drain. When applied to the drain, droplets were found in all but one wash basin, and this was more common in the absence of a drain plug. Sink design considerations to install drain plugs, reduce dripping and offset the tap may help to prevent transmission from drains.

Incomplete surgical staging in clinical early-stage ovarian cancer: guidelines versus daily practice.

BACKGROUND: Incomplete surgical staging of patients with early-stage epithelial ovarian cancer (EOC) has been reported in up to 98% of cases, when based on the International Federation of Obstetrics and Gynecology (FIGO) staging procedure. The aim of the present retrospective study was to clarify the reasons for incomplete staging. METHODS: The PRISMA (Prevention Recovery Information System for Monitoring and Analysis) technique was used to evaluate cases with FIGO I-IIa EOC based on incomplete staging from five gynecologic oncologic center hospitals in the Netherlands in the period 2010-2014. RESULTS: Fifty cases with an incomplete surgical staging of EOC according to national guidelines were included. The most common reasons for incomplete staging were insufficient random biopsies of the peritoneum (n = 34, 68%), and less than ten lymph nodes being resected and/or found at pathology (n = 16, 32%). The most mentioned reason for not performing biopsies was, besides forgetting to do so, believing that after careful inspection and palpation, taking biopsies is irrelevant and/or already are being taken while performing a hysterectomy (peritoneum of cul-de-sac, bladder). The value of contralateral pelvic lymph node dissection in case of a unilateral ovarian malignancy was also doubted, influencing the number of lymph nodes resected. CONCLUSIONS: The most important reasons for incomplete staging in EOC are, besides omitting elements by accident, questioning the importance of obligatory elements of the staging procedure. A structured list of staging steps during surgery and more evidence-based consensus concerning these obligatory elements might increase the number of complete staging procedures in EOC.

The daily direct costs of isolating patients identified with highly resistant micro-organisms in a non-outbreak setting.

BACKGROUND: Isolation precautions are recommended when caring for patients identified with highly resistant micro-organisms (HRMOs). However, the direct costs of patients in isolation are largely unknown. AIM: To obtain detailed information on the daily direct costs associated with isolating patients identified with HRMOs. METHODS: This study was performed from November until December 2017 on a 12-bed surgical ward. This ward contained solely isolation rooms with anterooms. The daily direct costs of isolation were based on three cost items: (1) additional personal protective equipment (PPE), measured by counting the consumption of empty packaging materials; (2) cleaning and disinfection of the isolation room, based on the costs of an outsourced cleaning company; and (3) additional workload for healthcare workers, based on literature and multiplied by the average gross hourly salary of nurses. A distinction was made between the costs for strict isolation, contact-plus isolation, and contact isolation. FINDINGS: During the study period, 26 patients were nursed in isolation because of HRMO carriage. Time for donning and doffing of PPE was 31 min per day. The average daily direct costs of isolation were the least expensive for contact isolation (gown, gloves), €28/$31, and the most expensive for strict isolation (surgical mask, gloves, gown, cap), €41/$47. CONCLUSION: Using a novel, easy method to estimate consumption of PPE, we conclude that the daily direct costs of isolating a patient differ per type of isolation. Insight into the direct costs of isolation is of utmost importance when developing or updating infection prevention policies.

The effect of a hand hygiene intervention on infections in residents of nursing homes: a cluster randomized controlled trial.

BACKGROUND: The primary goal of hand hygiene is to reduce infectious disease rates. We examined if a nursing home's participation in a hand hygiene intervention resulted in residents having fewer healthcare associated infections (HAIs) when compared to nursing homes without the hand hygiene intervention. METHODS: This study is a part of a cluster randomized controlled trial (RCT) in 33 nursing homes to improve hand hygiene (HANDSOME). The incidence of five illnesses was followed over 13 months: gastroenteritis, influenza-like illness, pneumonia, urinary tract infections and infections from methicillin-resistant Staphylococcus aureus (MRSA). Incidence rates per study arm were reported for baseline (October-December 2016) and two follow-up periods (January-April 2017, May-October 2017). HAI rates were compared in a Poisson multilevel analysis, correcting for baseline differences (the baseline infection incidence and the size of the nursing home), clustering of observations within nursing homes, and period in the study. RESULTS: There was statistically significantly more gastroenteritis (p < 0.001) and statistically significantly less influenza-like illness (p < 0.01) in the intervention arm when compared to the control arm. There were no statistically significant differences or pneumonia, urinary tract infections, and MRSA infections in the intervention arm when compared to the control arm. In a sensitivity analysis, gastroenteritis was no longer statistically significantly higher in the intervention arm (p = 0.92). CONCLUSIONS: As in comparable studies, we could not conclusively demonstrate the effectiveness of an HH intervention in reducing HAIs among residents of nursing homes, despite the use of clearly defined outcome measures, a standardized reporting instrument, and directly observed HH in a multicenter cluster RCT. Trial registration Netherlands Trial Register, trial NL6049 (NTR6188). Registered October 25, 2016, https://www.trialregister.nl/trial/6049 .