Unveiling 8 years of duodenoscope contamination: insights from a retrospective analysis in a large tertiary care hospital.

OBJECTIVE: Contaminated duodenoscopes caused several hospital outbreaks. Despite efforts to reduce contamination rates, 15% of patient-ready duodenoscopes are still contaminated with gastrointestinal microorganisms. This study aimed to provide an overview of duodenoscope contamination over time, identify risk factors and study the effects of implemented interventions. DESIGN: Duodenoscope culture sets between March 2015 and June 2022 at a Dutch tertiary care centre were analysed. Contamination was defined as (1) the presence of microorganisms of oral or gastrointestinal origin (MGO) or (2) any other microorganism with ≥20 colony-forming units/20 mL (AM20). A logistic mixed effects model was used to identify risk factors and assess the effect of interventions, such as using duodenoscopes with disposable caps, replacing automated endoscope reprocessors (AER) and conducting audits in the endoscopy department. RESULTS: A total of 404 culture sets were analysed. The yearly contamination rate with MGO showed great variation, ranging from 14.3% to 47.5%. Contamination with AM20 increased up to 94.7% by 2022. For both MGO and AM20, the biopsy and suction channels were the most frequently contaminated duodenoscope components. The studied interventions, including audits, AER replacement and implementation of duodenoscopes with disposable caps, did not show a clear association with contamination rates. CONCLUSION: Duodenoscope contamination remains a significant problem, with high contamination rates despite several interventions. Reprocessing the biopsy and suction channels is especially challenging. Changes in the design of reusable duodenoscopes, such as enabling sterilisation or easily replaceable channels, are necessary to facilitate effective duodenoscope reprocessing and to eliminate the risk of duodenoscope-associated infections.

Effect of a novel endoscope cleaning brush on duodenoscope contamination.

BACKGROUND: Current duodenoscope reprocessing protocols are insufficient to prevent contamination and require adaptations to prevent endoscopy-associated infections (EAIs). This study aimed to investigate the effect of a new endoscope cleaning brush on the contamination rate of ready-to-use duodenoscopes. METHODS: This retrospective before-and-after intervention study collected duodenoscope surveillance culture results from March 2018 to June 2022. Contamination was defined as ≥1 colony-forming unit of a microorganism of gut or oral origin (MGO). In December 2020, an endoscope cleaning brush with a sweeper design was introduced as an intervention in the manual cleaning of duodenoscopes. A logistic mixed-effects model was used to study the effects of this intervention. RESULTS: Data were collected from 176 culture sets before the new brush's introduction and 81 culture sets afterwards. Pre-introduction, culture sets positive with an MGO comprised 45.5% (95%CI 38.3%-52.8%; 80/176), decreasing to 17.3% (95%CI 10.6%-26.9%; 14/81) after implementation of the new brush. Compared with the former brush, duodenoscopes cleaned with the new brush had lower odds of contamination with MGOs (adjusted odds ratio 0.25, 95%CI 0.11-0.58; P=0.001) CONCLUSIONS: Use of the new brush in manual cleaning reduced contamination with MGOs and is expected to prevent EAIs. These findings should be confirmed in future prospective randomized studies.

Dynamics of Staphylococcus aureus in patients and the hospital environment in a tertiary care hospital in the Netherlands.

BACKGROUND: The dynamics of Staphylococcus aureus in patients and the hospital environment are relatively unknown. We studied these dynamics in a tertiary care hospital in the Netherlands. METHODS: Nasal samples were taken from adult patients at admission and discharge. Isolates cultured from clinical samples taken before and during hospitalization from these patients were included. Environmental samples of patient rooms were taken over a three-year period. Finally, isolates from clinical samples from patients with an epidemiological link to S. aureus positive rooms were included. Staphylococcal protein A (spa) typing was performed. RESULTS: Nasal samples were taken from 673 patients. One hundred eighteen (17.5%) were positive at admission and discharge, 15 (2.2%) patients acquired S. aureus during hospitalization. Nineteen patients had a positive clinical sample during hospitalization, 15.9% of the S. aureus were considered as from an exogenous source. One hundred and forty (2.8%) environmental samples were S. aureus positive. No persistent contamination of surfaces was observed. Isolates were highly diverse: spa typing was performed for 893 isolates, identifying 278 different spa types, 161 of these spa types were observed only once. CONCLUSION: Limited transmission could be identified between patients and the hospital environment, and from patient-to-patient. Exogenous acquisition was assumed to occur in 15% of clinical samples. Environmental contamination was infrequent, temporarily, and coincided with the strain from the patient admitted to the room at that time. MRSA was rare and not found in the environment.

Universal screening or a universal risk assessment combined with risk-based screening for multidrug-resistant microorganisms upon admission: Comparing strategies.

OBJECTIVE: Timely identification of patients who carry multidrug-resistant microorganisms (MDRO) is needed to prevent nosocomial spread to other patients and to the hospital environment. We aimed to compare the yield of a universal screening strategy upon admission to the currently installed universal risk assessment combined with risk-based screening upon admission. METHODS: This observational study was conducted within a prospective cohort study. From January 1, 2018, until September 1, 2019, patients admitted to our hospital were asked to participate. Nasal and perianal samples were taken upon admission and checked for the presence of MDRO. The results of the universal risk assessment and risk-based screening were collected retrospectively from electronic health records. RESULTS: In total, 1017 patients with 1069 separate hospital admissions participated in the study. Universal screening identified 38 (3.6%) unknown MDRO carriers upon admission (37 individual patients), all carrying extended-spectrum beta-lactamase-producing Enterobacterales. For 946 of 1069 (88.5%) patients, both the universal risk assessment and universal screening were performed. For 19 (2.0%) admissions, ≥1 risk factor was identified. The universal risk assessment identified one (0.1%) unknown carrier, compared to 37 out of 946 carriers for the universal screening (P<0.001). Of the 37 carriers identified through the universal screening, 35 (94.6%) reported no risk factors. CONCLUSIONS: Our results show that in our low endemic setting, a universal screening strategy identified significantly more MDRO carriers than the currently implemented universal risk-assessment. When implementing a universal risk-assessment, risk factors should be carefully selected to be able to identify ESBL-E carriers. While the universal screening identified more MDRO carriers, further research is needed to determine the cost-effectiveness of this strategy.

Contact tracing for vancomycin-resistant Enterococcus faecium (VRE): evaluation of the Dutch policy of quintuple screening cultures.

Detection of vancomycin-resistant Enterococcus faecium (VRE) is hampered by low sensitivity of rectal swab cultures. This study aimed to define the number of screening cultures needed to increase sensitivity to detect VRE transmission, and to determine time from presumed exposure to detectable colonization. In a tertiary care setting, we retrospectively analyzed data from 9 VRE outbreaks. As a proxy or estimation for time to detectable colonization, the time between first positive culture of the presumed index patient and that of their contacts was determined. Only 64% of secondary cases were positive in the first out of five cultures. By using the first three out of five rectal swabs, 89% (95%CI: 78-95%) of all secondary cases would have been identified. The median number of days between the positive culture of the index patient and the first positive culture of secondary cases was 9 days. Eleven percent of secondary cases would have been missed if only three rectal samples would have been obtained. Furthermore, our results show that one or more rectal swabs taken around day 9 after presumed exposure should at least be included in the screening approach. In our setting, obtaining a fourth and a fifth rectal swab showed a relevant additional value compared to only one to three swabs. Our findings are useful for determining the most effective VRE contact tracing approach to prevent transmission.

Combining epidemiological data and whole genome sequencing to understand SARS-CoV-2 transmission dynamics in a large tertiary care hospital during the first COVID-19 wave in The Netherlands focusing on healthcare workers.

BACKGROUND: Healthcare facilities have been challenged by the risk of SARS-CoV-2 transmission between healthcare workers (HCW) and patients. During the first wave of the COVID-19 pandemic, infections among HCW were observed, questioning infection prevention and control (IPC) measures implemented at that time. AIM: This study aimed to identify nosocomial transmission routes of SARS-CoV-2 between HCW and patients in a tertiary care hospital. METHODS: All SARS-CoV-2 PCR positive HCW and patients identified between 1 March and 19 May 2020, were included in the analysis. Epidemiological data were collected from patient files and HCW contact tracing interviews. Whole genome sequences of SARS-CoV-2 were generated using Nanopore sequencing (WGS). Epidemiological clusters were identified, whereafter WGS and epidemiological data were combined for re-evaluation of epidemiological clusters and identification of potential transmission clusters. HCW infections were further classified into categories based on the likelihood that the infection was acquired via nosocomial transmission. Secondary cases were defined as COVID-19 cases in our hospital, part of a transmission cluster, of which the index case was either a patient or HCW from our hospital. FINDINGS: The study population consisted of 293 HCW and 245 patients. Epidemiological data revealed 36 potential epidemiological clusters, with an estimated 222 (75.7%) HCW as secondary cases. WGS results were available for 195 HCW (88.2%) and 20 patients (12.8%) who belonged to an epidemiological cluster. Re-evaluation of the epidemiological clusters, with the available WGS data identified 31 transmission clusters with 65 (29.4%) HCW as secondary cases. Transmission clusters were all part of 18 (50.0%) previously determined epidemiological clusters, demonstrating that several larger outbreaks actually consisted, of several smaller transmission clusters. A total of 21 (7.2%) HCW infections were classified as from confirmed nosocomial, of which 18 were acquired from another HCW and 3 from a patient. CONCLUSION: The majority of SARS-CoV-2 infections among HCW could be attributed to community-acquired infection. Infections among HCW that could be classified as due to nosocomial transmission, were mainly caused by HCW-to-HCW transmission rather than patient-to-HCW transmission. It is important to recognize the uncertainties of cluster analyses based solely on epidemiological data.

Outbreak investigations after identifying carbapenem-resistant Pseudomonas aeruginosa: a systematic review.

BACKGROUND: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) are a serious cause of healthcare-associated infections. Part of the infection prevention and control measures are outbreak investigations (OI) of patients, healthcare workers (HCW), and the environment after identifying a CRPA in order to identify carriers and environmental reservoirs, so that targeted actions can be taken to prevent further transmission. However, little is known on when and how to perform such OI. Therefore, this systematic review aims to summarize OI performed after detection of CRPA in the endemic and epidemic hospital setting. MAIN TEXT: Articles related to our research question were identified through a literature research in multiple databases (Embase, Medline Ovid, Cochrane, Scopus, Cinahl, Web of Science, and Google Scholar) until January 12, 2022 (Prospero registration number CRD42020194165). Hundred-twenty-six studies were included. In both the endemic and the epidemic setting, a median number of two out of seven predefined components of OI were identified. In the endemic setting, the most frequent component of OI was screening of the environment (28 studies, 62.2%). In the epidemic setting, screening of the environment (72 studies, 88.9%), and screening of patients during hospitalization (30 studies, 37%) were most frequently performed. Only 19 out of 126 studies (15.1%) reported screening of contact patients, and 37 studies reported screening of healthcare workers (HCW, 29.4%). CONCLUSION: Due to probable underreporting of OI in the literature, the available evidence for the usefulness of the individual components of OI is scarce. This could lead to inhomogeneous performance of OI after detection of CRPA in the healthcare setting, and with this, potential under- or overscreening. While we could show evidence for the usefulness for environmental screening in order to identify the mode of transmission, evidence for HCW screening is scarce and might not lead to the identification of modes of transmission. Further studies are needed to better understand CI in different settings and, finally, develop guidance on when and how to best perform OI.

Limiting spread of VIM-positive Pseudomonas aeruginosa from colonized sink drains in a tertiary care hospital: A before-and-after study.

BACKGROUND: In healthcare environments, sinks are being increasingly recognized as reservoirs for multidrug-resistant Gram-negative bacteria. In our hospital, carbapenemase-producing, Verona Integron-encoded Metallo-beta-lactamase (VIM)-positive Pseudomonas aeruginosa (VIM-PA) was detected at low endemicity in patients, and environmental culturing revealed that sink drains were primary reservoirs. Therefore, an intervention was initiated in several wards to install sink drain plugs as physical barriers against splashing to prevent transmission of VIM-PA from drain reservoirs to the surrounding sink environment. AIM: To assess the efficacy of the intervention on limiting spread of VIM-PA. METHODS: Swabs were taken from inner sink environments (i.e. drains), and outer sink environments (i.e. wash basins, faucet aerators, and countertops) twice before and three times after the intervention. Siphon water and drain wells were also sampled before and at the moment of the intervention, respectively. All samples were screened for VIM-PA, and isolates were typed with multiple-locus variable-number tandem repeat analysis (MLVA). RESULTS: There was a significant reduction in VIM-PA positivity in both inner (P-value <0.001) and outer (P-value 0.001) sink environments after the intervention. However, VIM-PA recolonization was observed in the inner sink environments of patient rooms, and also in rooms exclusive to healthcare personnel, over time. Surfaces in the outer sink environment were rarely positive for VIM-PA after the intervention. MLVA revealed three genetic clusters, with one found in all wards and room types during the study period. CONCLUSIONS: Drain plugs are a simple and effective infection prevention and control measure to contain spread of VIM-PA from drain reservoirs.

Infection prevention and control in Indonesian hospitals: identification of strengths, gaps, and challenges.

BACKGROUND: Infection prevention and control (IPC) in hospitals is key to safe patient care. There is currently no data regarding the implementation of IPC in hospitals in Indonesia. The aim of this study was to assess the existing IPC level in a nationwide survey, using the World Health Organization (WHO) IPC assessment framework tool (IPCAF), and to identify strengths, gaps, and challenges. METHODS: A cross-sectional study was conducted from July to November 2021. Of all general hospitals in Indonesia, 20% (N = 475) were selected using stratified random sampling based on class (A, B, C and D; class D with a maximum of 50 beds and class A with ≥ 250 beds) and region. The IPCAF was translated into Indonesian and tested in four hospitals. Questions were added regarding challenges in the implementation of IPC. Quantitative IPCAF scores are reported as median (minimum-maximum). IPC levels were calculated according to WHO tools. RESULTS: In total, 355 hospitals (74.7%) participated in this study. The overall median IPCAF score was 620.0 (535.0-687.5). The level of IPC was mostly assessed as advanced (56.9% of hospitals), followed by intermediate (35.8%), basic (7.0%) and inadequate (0.3%). In the eastern region of the country, the majority of hospitals scored intermediate level. Of the eight core components, the one with the highest score was IPC guidelines. Almost all hospitals had guidelines on the most important topics, including hand hygiene. Core components with the lowest score were surveillance of healthcare-associated infections (HAIs), education and training, and multimodal strategies. Although > 90% of hospitals indicated that surveillance of HAIs was performed, 57.2% reported no availability of adequate microbiology laboratory capacity to support HAIs surveillance. The most frequently reported challenges in the implementation of IPC were communication with the management of the hospitals, followed by the unavailability of antimicrobial susceptibility testing results and insufficient staffing of full-time IPC nurses. CONCLUSION: The IPC level in the majority of Indonesian hospitals was assessed as advanced, but there was no even distribution over the country. The IPCAF in combination with interviews identified several priority areas for interventions to improve IPC in Indonesian hospitals.

Environmental contamination with highly resistant microorganisms after relocating to a new hospital building with 100% single-occupancy rooms: A prospective observational before-and-after study with a three-year follow-up.

INTRODUCTION: Inanimate surfaces within hospitals can be a source of transmission for highly resistant microorganisms (HRMO). While many hospitals are transitioning to single-occupancy rooms, the effect of single-occupancy rooms on environmental contamination is still unknown. We aimed to determine differences in environmental contamination with HRMO between an old hospital building with mainly multiple-occupancy rooms and a new hospital building with 100% single-occupancy rooms, and the environmental contamination in the new hospital building during three years after relocating. METHODS: Environmental samples were taken twice in the old hospital, and fifteen times over a three-year period in the new hospital. Replicate Organism Direct Agar Contact-plates (RODACs) were used to determine colony forming units (CFU). Cotton swabs premoistened with PBS were used to determine presence of methicillin-resistant Staphylococcus aureus, carbapenemase-producing Pseudomonas aeruginosa, highly resistant Enterobacterales, carbapenem-resistant Acinetobacter baumannii, and vancomycin-resistant Enterococcus faecium. All identified isolates were subjected to whole genome sequencing (WGS) using Illumina technology. RESULTS: In total, 4993 hospital sites were sampled, 724 in the old and 4269 in the new hospital. CFU counts fluctuated during the follow-up period in the new hospital building, with lower CFU counts observed two- and three years after relocating, which was during the COVID-19 pandemic. The CFU counts in the new building were equal to or surpassed the CFU counts in the old hospital building. In the old hospital building, 24 (3.3%) sample sites were positive for 49 HRMO isolates, compared to five (0.1%) sample sites for seven HRMO isolates in the new building (P < 0.001). In the old hospital, 89.8% of HRMO were identified from the sink plug. In the new hospital, 71.4% of HRMO were identified from the shower drain, and no HRMO were found in sinks. DISCUSSION: Our results indicate that relocating to a new hospital building with 100% single-occupancy rooms significantly decreases HRMO in the environment. Given that environmental contamination is an important source for healthcare associated infections, this finding should be taken into account when considering hospital designs for renovations or the construction of hospitals.

Impact of an external ventricular shunt (EVD) handling protocol on secondary meningitis rates: a historical cohort study with propensity score matching.

BACKGROUND: External ventricular drainage (EVD) is frequently used in neurosurgical procedures for cerebrospinal fluid (CSF) drainage. It is, however, associated with high infection rates, namely secondary meningitis and ventriculitis. Based on a previous high prevalence of these infections among patients with EVDs, we have proposed and implemented a protocol in an effort to decrease the infection rate. The aim of this study was to measure the effect of hospital-wide implementation of the EVD handling protocol on secondary EVD infections. PATIENTS AND METHODS: We included 409 consecutive patients who received a new EVD for other indications than infectious pathologies from January 2000 until June 2012. Patients above 18 years of age were divided into pre- (n = 228) and post-protocol (n = 181) groups. Patient and disease demographics, as well as EVD data together with confounders for secondary meningitis were recorded in a database. Propensity score matching was then performed to create groups matched for sex, age, reason for drainage, type of shunt, time in situ and duration of surgery to place the EVD. Binomial logistic regression for confounder adjustment and regression discontinuity analyses were then performed on the matched cohort. RESULTS: Infections occurred more frequently in the pre-protocol group (23% vs 9%, p <  0.001). The incidence of infection was 33/1000 drain-days pre-protocol and 9/1000 drain-days post-protocol. Regression analysis in a propensity score-matched cohort (n = 103 in the pre- and n = 178 in the post-protocol groups) showed that the pre-protocol period was independently associated with more infections (OR 2.69; 95%-CI 1.22-5.95, p = 0.01). CONCLUSIONS: The incidence of secondary EVD infections can be reduced significantly by the implementation of a strict hospital-wide EVD handling protocol.

Infection prevention and control policies in hospitals and prevalence of highly resistant microorganisms: an international comparative study.

BACKGROUND: There are differences in infection prevention and control (IPC) policies to prevent transmission of highly resistant microorganisms (HRMO). The aim of this study is to give an overview of the IPC policy of six European hospitals and their HRMO prevalence, to compare the IPC policies of these hospitals with international guidelines, and to investigate the hospitals' adherence to their own IPC policy. METHODS: The participating hospitals were located in Salzburg (Austria), Vienna (Austria), Kayseri (Turkey), Piraeus (Greece), Rome (Italy) and Rotterdam (The Netherlands). Data were collected via an online survey. Questions were aimed at prevalence rates in the years 2014, 2015, 2016 of carbapenemase-producing Klebsiella pneumoniae (CPK), carbapenemase-producing Pseudomonas aeruginosa (CPPA), vancomycin-resistant Enterococcus faecium (VRE) and hospitals' IPC policies of 2017. Implemented IPC measures (i.e. with a self-reported adherence of > 90%) were counted (26 points maximal). RESULTS: The self-reported prevalence of CPK per year was low in the Austrian and Dutch hospitals and high in the Turkish and Greek hospitals. CPPA was highly prevalent in the Turkish hospital only, while the prevalence of VRE in four hospitals, except the Austrian hospitals which reported lower prevalence numbers, was more evenly distributed. The Dutch hospital had implemented the most IPC measures (n = 21), the Turkish and Greek hospitals the least (n = 14 and 7, respectively). CONCLUSION: Hospitals with the highest self-reported prevalence of CPK and CPPA reported the least implemented IPC measures. Also, hospitals with a higher prevalence often reported a lower adherence to own IPC policy.

Admissions to a large tertiary care hospital and Omicron BA.1 and BA.2 SARS-CoV-2 polymerase chain reaction positivity: primary, contributing, or incidental COVID-19.

OBJECTIVES: SARS-CoV-2 Omicron variants BA.1 and BA.2 seem to show reduced clinical severity compared with earlier variants. Therefore, we aimed to assess and classify the cause of hospitalization for patients with COVID-19 identified with these Omicron variants in our hospital. METHODS: A retrospective analysis was performed on all patients identified with the SARS-CoV-2 Omicron variant between December 23, 2021, and February 27, 2022. Patients with a positive SARS-CoV-2 polymerase chain reaction (PCR) upon clinical admission or during clinical admission were classified into four categories: (1) primary COVID-19, (2) admission-contributing COVID-19, (3) incidental COVID-19, and (4) undetermined COVID-19. RESULTS: We classified 172 COVID-19 Omicron patient admissions, including 151 adult and 21 pediatric patients. Of the adult patients, 45% were primary COVID-19 cases, 21% were admission-contributing, 31% were incidental, and 3% were undetermined. Of the pediatric patients, 19% were primary COVID-19 cases, 29% were admission-contributing, 38% were incidental, and 14% were undetermined. CONCLUSION: In the evolving landscape of COVID-19, the number of hospitalized patients with COVID-19 should be interpreted with caution. The different patient categories should be considered in public health policy decision-making and when informing the general public.

Pre-COVID-19 international travel and admission to hospital when back home: travel behavior, carriage of highly resistant microorganisms, and risk perception of patients admitted to a large tertiary care hospital.

BACKGROUND: When people who recently travelled abroad are admitted to a hospital back home, there is a risk of introducing highly resistant microorganisms (HRMO) into the hospital. To minimize this risk, a feasible infection prevention strategy should be developed. In this study, we investigated patients' travel history and behavior during travel and analyzed whether this was correlated to HRMO carriage at admission. METHODS: From May 2018 until August 2019, adult patients admitted to a large tertiary care center in the Netherlands were asked upon hospital admission to participate in the study. Included patients received a questionnaire about risk perception, travel history in the last year, and behavior during travel, and were screened for HRMO carriage at admission using a perianal swab. RESULTS: Six hundred and eight questionnaires were handed out, of which 247 were returned (40.6%). One hundred and thirty (52.6%) patients did not travel abroad in the last year, of whom eight (6.2%) were HRMO carrier at admission. One hundred seventeen (47.4%) patients travelled in the preceding year, of whom seven patients (6.0%) were HRMO carrier at admission. Thirty patients (12%) travelled outside of Europe; in this group HRMO prevalence was 13.3% (4 out of 30). The majority of patients (71.3%) were aware that international travel could lead to carriage of HRMO, and an even larger majority (89.5%) would support a screening strategy upon hospital admission in case of a travel history, to minimize the risk of introducing HRMO. CONCLUSIONS: We identified that half of admitted patients to a large tertiary care hospital travelled abroad in the last year, with only a small percentage outside Europe. We discuss several screening strategies and propose a strategy of screening and preemptive isolation of patients who travelled to Asia or Africa in the 2 months before their hospital admission; a strategy that patients would support.

The effect of 100% single-occupancy rooms on acquisition of extended-spectrum beta-lactamase-producing Enterobacterales and intra-hospital patient transfers: a prospective before-and-after study.

BACKGROUND: Extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) are a well-known cause of healthcare-associated infections. The implementation of single-occupancy rooms is believed to decrease the spread of ESBL-E. Additionally, implementation of single-occupancy rooms is expected to reduce the need for intra-hospital patient transfers. We studied the impact of a new hospital with 100% single-occupancy rooms on the acquisition of ESBL-E and on intra-hospital patient transfers. METHODS: In 2018, the Erasmus MC University Medical Center moved from an old, 1200-bed hospital with mainly multiple-occupancy rooms, to a newly constructed 522-bed hospital with 100% single-occupancy rooms. Adult patients admitted between January 2018 and September 2019 with an expected hospitalization of ≥ 48 h were asked to participate in this study. Perianal samples were taken at admission and discharge. Patient characteristics and clinical information, including number of intra-hospital patient transfers, were collected from the patients' electronic health records. RESULTS: Five hundred and ninety-seven patients were included, 225 in the old and 372 in the new hospital building. Fifty-one (8.5%) ESBL-E carriers were identified. Thirty-four (66.7%) patients were already positive at admission, of which 23 without recent hospitalization. Twenty patients acquired an ESBL-E, seven (3.1%) in the old and 13 (3.5%) in the new hospital building (P = 0.801). Forty-one (80.4%) carriers were only detected by the active screening performed during this study. Only 10 (19.6%) patients, six before and four during hospitalization, showed ESBL-E in a clinical sample taken on medical indication. Fifty-six (24.9%) patients were transferred to other rooms in the old hospital, compared to 53 (14.2%) in the new hospital building (P = 0.001). Intra-hospital patient transfers were associated with ESBL-E acquisition (OR 3.18, 95%CI 1.27-7.98), with increasing odds when transferred twice or more. CONCLUSION: Transitioning to 100% single-occupancy rooms did not decrease ESBL-E acquisition, but did significantly decrease the number of intra-hospital patient transfers. The latter was associated with lower odds on ESBL-E acquisition. ESBL-E carriers remained largely unidentified through clinical samples. TRIAL REGISTRATION: This study was retrospectively registered in the Dutch National Trial Register on 24-02-2020, with registration number NL8406.

Routes of transmission of VIM-positive Pseudomonas aeruginosa in the adult intensive care unit-analysis of 9 years of surveillance at a university hospital using a mathematical model.

BACKGROUND: Hospital outbreaks of multidrug resistant Pseudomonas aeruginosa are often caused by Pseudomonas aeruginosa clones which produce metallo-ß-lactamases, such as Verona Integron-encoded Metallo-ß-lactamase (VIM). Although different sources have been identified, the exact transmission routes often remain unknown. However, quantifying the role of different transmission routes of VIM-PA is important for tailoring infection prevention and control measures. The aim of this study is to quantify the relative importance of different transmission routes by applying a mathematical transmission model using admission and discharge dates as well as surveillance culture data of patients. METHODS: We analyzed VIM-PA surveillance data collected between 2010 and 2018 of two intensive-care unit (ICU) wards for adult patients of the Erasmus University Medical Center Rotterdam using a mathematical transmission model. We distinguished two transmission routes: direct cross-transmission and a persistent environmental route. Based on admission, discharge dates, and surveillance cultures, we estimated the proportion of transmissions assigned to each of the routes. RESULTS: Our study shows that only 13.7% (95% CI 1.4%, 29%) of the transmissions that occurred in these two ICU wards were likely caused by cross-transmission, leaving the vast majority of transmissions (86.3%, 95% CI 71%, 98.6%) due to persistent environmental contamination. CONCLUSIONS: Our results emphasize that persistent contamination of the environment may be an important driver of nosocomial transmissions of VIM-PA in ICUs. To minimize the transmission risk from the environment, potential reservoirs should be regularly and thoroughly cleaned and disinfected, or redesigned.