Sink Drain Research Articles

Evaluation of a peracetic-acid-based sink drain disinfectant on the intensive care unit of a tertiary care centre in Belgium

Sink drains in hospitals are notorious reservoirs of bacteria, hosting both planktonic microorganisms and biofilms within the siphon. Considering that disinfectants based on peracetic acid are both non-corrosive and effective in eliminating biofilm and planktonic microorganisms, they present a potential solution for decontaminating sink drains. In this study, we examined the effectiveness of Clinell Drain Disinfectant®, a peracetic acid-based disinfectant, in the intensive care unit (ICU) of UZ Brussel, a department that has been confronted with nosocomial infections linked to sinks for several years. All 10 sinks in one of the ICU subunits proven to be heavily contaminated were treated with Clinell Drain Disinfectant® for one month, as prescribed by the manufacturer. Throughout the treatment period, bacterial growth in the P-traps was systematically monitored both qualitatively (using eSwab®) and quantitatively (employing a sterile catheter and syringe) on various selective agar plates, processed and incubated in the WASPLab® system. MALDI-TOF MS was used to identify all morphologically distinct colonies. Additionally, the utilization of O.K.N.V-RESIST5® allowed the identification of some clinically relevant acquired resistance mechanisms. At baseline, most of the sink drains were colonized by high concentrations of multidrug-resistant microorganisms, primarily VIM-producing P. aeruginosa. Our study demonstrated the disinfectant's efficacy in decontaminating the P-trap liquid, as the cultures taken immediately after decontamination yielded negative results, with only a very few exceptions. Nonetheless, it was observed that the biofilm in the upper section of the drain system remained unaffected, and within two days, it was capable of recolonizing the liquid in the P-traps at a concentration exceeding 100 000 CFU/mL. After one month, this disinfecting protocol did not result in a lasting decontamination of the sink drains.

A far ultraviolet-C light technology is effective for decontamination of items in proximity to sinks and is enhanced by a far UV-C reflective surface.

Dispersal of gram-negative bacilli from sink drains has been implicated as a source of transmission in multiple outbreaks. In an acute care hospital, we assessed how often patient care supplies and other frequently touched items were within 1 meter of sink drains. We tested the efficacy of a ceiling-mounted far ultraviolet-C (UV-C) light technology for decontamination of sink bowls and surfaces near sinks with and without a wall-mounted film that reflects far UV-C light. Of 190 sinks assessed, 55 (29%) had patient care supplies or other frequently touched items within 1 meter of the drain. The far UV-C technology reduced Pseudomonas aeruginosa, Enterobacter cloacae and Candida auris on steel disk carriers by ≥1.5 log10 colony-forming units (CFU) in 45 minutes. On inoculated real-world items, ≥1.9 log10 CFU reductions in P. aeruginosa were achieved on sites in line with the light source versus 0.4-1.8 log10 CFU reductions on shaded surfaces. The addition of the reflective surface significantly enhanced efficacy in shaded sites (P < 0.01). In a hospital setting, patient care supplies and other frequently touched items were often in proximity to sinks. The far UV-C light technology could potentially be useful for sink decontamination in high-risk areas.

Containment of a KPC-CRE Outbreak Associated with Premise Plumbing in a Long-Term Care Facility— Minnesota, 2022-2023

Background: On March 23, 2022, the Minnesota Department of Health (MDH) was notified of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella oxytoca isolated from a resident’s urine in long-term care facility A (LTCF-A). Carbapenem-resistant Enterobacterales (CRE) are reportable statewide with required isolate submission to MDH Public Health Laboratory (MDH-PHL), where carbapenemase production and mechanism identification is confirmed. Methods: MDH partnered with LTCF-A on a containment response, including infection prevention and control (IPC) measures, KPC-CRE education, and colonization screening. Rectal swabs were screened for carbapenemase genes by real-time PCR (Cepheid Xpert Carba-R), with positive specimens undergoing culture, isolation, and whole genome sequencing (WGS). MDH-PHL conducted WGS including multilocus sequence typing (MLST) and single nucleotide polymorphism (SNP) analysis to describe genetic relationships among isolates. When screening indicated a potential environmental source, due to species diversity and ongoing resident transmission, an environmental screening plan was developed including collection of premise plumbing samples from room faucets, aerators, sinks, toilets, and shared shower drains. Results: KPC-CRE was detected in 23 residents (urine, n=2; rectal swab, n=21) during March 2022–November 2023. 21 isolates comprising 10 Enterobacterales species were cultured from KPC-positive screening specimens. SNP analysis performed on bacteria of the same species demonstrated 5 distinct clusters of relatedness comprising 2-3 residents per cluster (Cluster 1: Klebsiella oxytoca, n=3; Cluster 2: Klebsiella oxytoca, n=3; Cluster 3: Escherichia coli, n=2; Cluster 4: Klebsiella pneumoniae, n=2; Cluster 5: Raoultella planticola, n=2). 7 KPC-positive resident specimens did not yield a culturable organism. KPC-CRE was detected throughout the premise plumbing including 8 of 9 shared shower room drains and 6 of 75 resident room sink drains. WGS and SNP analysis suggest relatedness among resident and environmental KPC-CRE isolates. Gaps in IPC measures including hand hygiene, use of personal protective equipment (PPE), environmental cleaning and disinfection, and sink hygiene practices were observed during onsite assessments. Use of an EPA-registered biofilm disinfectant in facility drains and repeated environmental sampling has demonstrated a decrease in KPC-harboring bacteria within the premise plumbing, but not complete elimination. Conclusion: Containing the spread of KPC-CRE within LTCF-A has been challenging due to environmental reservoirs of KPC-CRE along with insufficient implementation of IPC practices. Continued colonization screening has been necessary to detect newly colonized residents and reinforce efforts to increase IPC compliance. Strict implementation and adherence to IPC measures, including those that minimize the spread of KPC-CRE from facility premise plumbing, are needed to fully halt KPC-CRE transmission within LTCF-A.

Disinfection of sink drains to reduce a source of three opportunistic pathogens, during Serratia marcescens clusters in a neonatal intensive care unit.

Evaluate the effects of five disinfection methods on bacterial concentrations in hospital sink drains, focusing on three opportunistic pathogens (OPs): Serratia marcescens, Pseudomonas aeruginosa and Stenotrophomonas maltophilia. Over two years, three sampling campaigns were conducted in a neonatal intensive care unit (NICU). Samples from 19 sink drains were taken at three time points: before, during, and after disinfection. Bacterial concentration was measured using culture-based and flow cytometry methods. High-throughput short sequence typing was performed to identify the three OPs and assess S. marcescens persistence after disinfection at the genotypic level. This study was conducted in a pediatric hospitals NICU in Montréal, Canada, which is divided in an intensive and intermediate care side, with individual rooms equipped with a sink. Five treatments were compared: self-disinfecting drains, chlorine disinfection, boiling water disinfection, hot tap water flushing, and steam disinfection. This study highlights significant differences in the effectiveness of disinfection methods. Chlorine treatment proved ineffective in reducing bacterial concentration, including the three OPs. In contrast, all other drain interventions resulted in an immediate reduction in culturable bacteria (4-8 log) and intact cells (2-3 log). Thermal methods, particularly boiling water and steam treatments, exhibited superior effectiveness in reducing bacterial loads, including OPs. However, in drains with well-established bacterial biofilms, clonal strains of S. marcescens recolonized the drains after heat treatments. Our study supports thermal disinfection (>80°C) for pathogen reduction in drains but highlights the need for additional trials and the implementation of specific measures to limit biofilm formation.

Identifying and Remediating Super-splasher Sinks to Reduce Dispersal of Pathogens From Sink Drains.

Testing for dispersal of fluorescent gel from sink drains was sensitive for detection of sinks that dispersed gram-negative bacilli outside the bowl. Reducing the flow rate of sinks with rapid water inflow and/or elimination of obstruction leading to slow outflow was effective in preventing dispersal of fluorescence and gram-negative bacilli.

What is the optimal frequency of sink drain decontamination with a foam disinfectant?

What is the optimal frequency of sink drain decontamination with a foam disinfectant?

Colonisation of hospital surfaces from low- and middle-income countries by extended spectrum β-lactamase- and carbapenemase-producing bacteria

Hospital surfaces can harbour bacterial pathogens, which may disseminate and cause nosocomial infections, contributing towards mortality in low- and middle-income countries (LMICs). During the BARNARDS study, hospital surfaces from neonatal wards were sampled to assess the degree of environmental surface and patient care equipment colonisation by Gram-negative bacteria (GNB) carrying antibiotic resistance genes (ARGs). Here, we perform PCR screening for extended-spectrum β-lactamases (blaCTX-M-15) and carbapenemases (blaNDM, blaOXA-48-like and blaKPC), MALDI-TOF MS identification of GNB carrying ARGs, and further analysis by whole genome sequencing of bacterial isolates. We determine presence of consistently dominant clones and their relatedness to strains causing neonatal sepsis. Higher prevalence of carbapenemases is observed in Pakistan, Bangladesh, and Ethiopia, compared to other countries, and are mostly found in surfaces near the sink drain. Klebsiella pneumoniae, Enterobacter hormaechei, Acinetobacter baumannii, Serratia marcescens and Leclercia adecarboxylata are dominant; ST15 K. pneumoniae is identified from the same ward on multiple occasions suggesting clonal persistence within the same environment, and is found to be identical to isolates causing neonatal sepsis in Pakistan over similar time periods. Our data suggests persistence of dominant clones across multiple time points, highlighting the need for assessment of Infection Prevention and Control guidelines.

Epidemiology of healthcare-associated Pseudomonas aeruginosa in intensive care units: are sink drains to blame?

Pseudomonas aeruginosa (PA) is a common cause of healthcare-associated infection (PA-HAI) in the intensive care unit (ICU). To describe the epidemiology of PA-HAI in ICUs in Ontario, Canada, and to identify episodes of sink-to-patient PA transmission. This was a prospective cohort study of patients in six ICUs from 2018 to 2019, with retrieval of PA clinical isolates, and PA-screening of antimicrobial-resistant organism surveillance rectal swabs, and of sink drain, air, and faucet samples. All PA isolates underwent whole-genome sequencing. PA-HAI was defined using US National Healthcare Safety Network criteria. ICU-acquired PA was defined as PA isolated from specimens obtained ≥48h after ICU admission in those with prior negative rectal swabs. Sink-to-patient PA transmission was defined as ICU-acquired PA with close genomic relationship to isolate(s) previously recovered from sinks in a room/bedspace occupied 3-14 days prior to collection date of the relevant patient specimen. Over ten months, 72PA-HAIs occurred among 60/4263 admissions. The rate of PA-HAI was 2.40 per 1000 patient-ICU-days; higher in patients who were PA-colonized on admission. PA-HAI was associated with longer stay (median: 26 vs 3 days uninfected; P < 0.001) and contributed to death in 22/60 cases (36.7%). Fifty-eight admissions with ICU-acquired PA were identified, contributing 35/72 (48.6%) PA-HAIs. Four patients with five PA-HAIs (6.9%) had closely related isolates previously recovered from their room/bedspace sinks. Nearly half of PA causing HAI appeared to be acquired in ICUs, and 7% of PA-HAIs were associated with sink-to-patient transmission. Sinks may be an under-recognized reservoir for HAIs.

Protozoan predation enhances stress resistance and antibiotic tolerance in Burkholderia cenocepacia by triggering the SOS response.

Bacterivorous protists are thought to serve as training grounds for bacterial pathogens by subjecting them to the same hostile conditions that they will encounter in the human host. Bacteria that survive intracellular digestion exhibit enhanced virulence and stress resistance after successful passage through protozoa but the underlying mechanisms are unknown. Here we show that the opportunistic pathogen Burkholderia cenocepacia survives phagocytosis by ciliates found in domestic and hospital sink drains, and viable bacteria are expelled packaged in respirable membrane vesicles with enhanced resistance to oxidative stress, desiccation, and antibiotics, thereby contributing to pathogen dissemination in the environment. Reactive oxygen species generated within the protozoan phagosome promote the formation of persisters tolerant to ciprofloxacin by activating the bacterial SOS response. In addition, we show that genes encoding antioxidant enzymes are upregulated during passage through ciliates increasing bacterial resistance to oxidative radicals. We prove that suppression of the SOS response impairs bacterial intracellular survival and persister formation within protists. This study highlights the significance of protozoan food vacuoles as niches that foster bacterial adaptation in natural and built environments and suggests that persister switch within phagosomes may be a widespread phenomenon in bacteria surviving intracellular digestion.

Best practices for flexible endoscope high-level disinfection-an integrative review

Background: Flexible endoscopes have a complicated design which includes several small lumen channels intended to facilitate the flow of fluids, tissue, and tools through the length of the device. This complex design leads to reprocessing challenges for high-level disinfection (HLD) to ensure endoscopes are free from contaminants that could lead to hospital-acquired infections. The aim of this project was to identify optimal strategies and obstacles for each stage of flexible endoscope HLD through an integrative review with the goal of achieving reprocessing excellence. Methods: A literature search was conducted using PubMed/Medline and CINAHL databases. A total of 32 articles and six guidelines were included in the review. Results: Ten elements with best-practice recommendations of flexible endoscope HLD have been identified. The HLD elements that received the most literature support include quality assurance/process monitoring and manual cleaning/decontamination. Several barriers to the adequate performance of HLD elements were also identified. Conclusion: This integrative review applied varying levels of rigour to identify and synthesize best practices for the following HLD elements: point-of-use treatment, transport, leak testing, manual cleaning/decontamination, visual inspection, manual or automated HLD, rinsing/drying, storage/hang time, record keeping, and quality assurance/process monitoring.

A workflow for the detection of antibiotic residues, measurement of water chemistry and preservation of hospital sink drain samples for metagenomic sequencing

Hospital sinks are environmental reservoirs that harbour healthcare-associated (HCA) pathogens. Selective pressures in sink environments, such as antibiotic residues, nutrient waste and hardness ions, may promote antibiotic resistance gene (ARG) exchange between bacteria. However, cheap and accurate sampling methods to characterize these factors are lacking. To validate a workflow to detect antibiotic residues and evaluate water chemistry using dipsticks. Secondarily, to validate boric acid to preserve the taxonomic and ARG ('resistome') composition of sink trap samples for metagenomic sequencing. Antibiotic residue dipsticks were validated against serial dilutions of ampicillin, doxycycline, sulfamethoxazole and ciprofloxacin, and water chemistry dipsticks against serial dilutions of chemical calibration standards. Sink trap aspirates were used for a 'real-world' pilot evaluation of dipsticks. To assess boric acid as a preservative of microbial diversity, the impact of incubation with and without boric acid at ∼22°C on metagenomic sequencing outputs was evaluated at Day 2 and Day 5 compared with baseline (Day 0). The limits of detection for each antibiotic were: 3μg/L (ampicillin), 10μg/L (doxycycline), 20μg/L (sulfamethoxazole) and 8μg/L (ciprofloxacin). The best performing water chemistry dipstick correctly characterized 34/40 (85%) standards in a concentration-dependent manner. One trap sample tested positive for the presence of tetracyclines and sulphonamides. Taxonomic and resistome composition were largely maintained after storage with boric acid at ∼22°C for up to five days. Dipsticks can be used to detect antibiotic residues and characterize water chemistry in sink trap samples. Boric acid was an effective preservative of trap sample composition, representing a low-cost alternative to cold-chain transport.

981. Sink drain environmental hygiene intervention successfully reduces burden of AROs

Abstract Background Healthcare associated infections (HAIs) and outbreaks due to hospital sinks have been noted for many years, however, there remains no standardized environmental hygiene protocol to combat these HAIs. The goal of this study was to evaluate the impact of a sink environmental hygiene intervention on gram negative microbial load. Methods We implemented our intervention across 18 rooms in two ICUs at Barnes Jewish Hospital in St. Louis, USA (Figure 1). At low frequency (1x/week) and high frequency (5x/week) intervals, we wiped sink surfaces with 10% bleach wipes and pumped (Foam-It Pump, FOAMit, Grand Rapids, MI) hydrogen-peroxide based foam (Virasept, Ecolab, St. Paul, MN) into sink drains, allowing a contact time of 3 minutes before rinsing. Control rooms received no intervention. We used E-swabs (Copan, Murrieta, CA) to swab sink drains and surrounding surfaces during a pre-intervention, two intervention, and two post-intervention periods. Swabs and water samples were selectively cultured for AROs, and isolates were identified using MALDI-TOF MS. We also obtained information on HAIs that occurred in the ICUs during the study period. Study design overview. We tested 2 frequencies of a disinfectant foam pump and bleach wipe intervention in 18 rooms across a SCTO ICU and SICU at Barnes Jewish Hospital. We sampled multiple surfaces including sink drains across a baseline phase (Phase 1), intervention phase (Phase 2), post-intervention phase (Phase 3), a second intervention phase (Phase 4), and another post intervention phase (Phase 5). Results Sink drains yielded the most unique AROs compared to other surfaces. The most identified AROs were P. aeruginosa and S. maltophilia (Figure 2). The intervention reduced total microbial and gram-negative burden at both frequencies, with the high frequency reducing the fraction of sink drains yielding gram-negatives by &amp;gt;80% (p&amp;lt; 0.05, Figure 3). The low and high frequencies reduced the fraction of sink drains yielding P. aeruginosa (62-82% and 81-100%, respectively) or S. maltophilia (44-68% and 72-94%, respectively); for many weeks neither was recovered (Figure 4). The number of HAIs (n=69) recorded was insufficient to comment on impacts on HAIs. In-room sink drains yielded the most AROs. a) Average weekly fraction of rooms with growth on BAP from each site. Average weekly b) unique ARO isolates c) fraction of rooms yielding P. aeruginosa and d) fraction of rooms yielding S. maltophilia. Permutation test, BH corrected. Both interventions reduced the fraction of rooms with culturable growth. Average weekly fraction of rooms in each intervention group that yielded culturable growth on a) BAP and b) MAC plates. Dunn’s test with BH correction was used to evaluate differences between groups in Phase 1 (baseline). Changes within groups versus Phase 1 were tested using permutation tests and BH corrected. Significant changes are denoted above the phase that has changed versus Phase 1 as follows: *: p ≤ 0.05, **: p ≤ 0.01. Interventions reduced the fraction of in-room sink drains yielding ARO isolates. a) Weekly counts per sink drain of unique AROs. Fraction of rooms yielding b) P. aeruginosa and c) S. maltophilia from in-room sink drain. Both interventions significantly reduced culturable ARO isolates, and frequently resulted in no P. aeruginosa or S. maltophilia collected for multiple weeks. Significant changes are denoted above the phase that has changed versus Phase 1 as follows: *: p ≤ 0.05, **: p ≤ 0.01. Conclusion As antibiotic resistance continues to rise, preventing HAIs caused by AROs becomes increasingly important. There are no standardized sink drain environmental hygiene protocols, even as outbreaks tied to sink drain colonization are regularly reported. This protocol effectively reduced ARO colonization of sinks drains. While larger studies are needed to observe effects of this intervention on HAIs, this study provides a promising tool for combatting sink drain-associated HAIs. Disclosures Carey-Ann Burnham, PhD, Pattern Bioscience: Stocks/Bonds

Long-term intensive care unit outbreak of carbapenemase-producing organisms associated with contaminated sink drains

Between 2018 and 2022, a Belgian tertiary care hospital faced a growing issue with acquiring carbapenemase-producing organisms (CPO), mainly VIM-producing P. aeruginosa (PA-VIM) and NDM-producing Enterobacterales (CPE-NDM) among hospitalized patients in the adult intensive care unit (ICU). We report the investigation of this ICU long-term CPO outbreak involving multiple species and a persistent environmental reservoir. Active case finding, environmental sampling, whole genome sequencing (WGS) analysis of patient and environmental strains and implemented control strategies were described in this study. From 2018 to 2022, 37 patients became colonised or infected with PA-VIM and/ or CPE-NDM during their ICU stay. WGS confirmed the epidemiological link between clinical and environmental strains collected from the sink drains with clonal strains dissemination and horizontal gene transfer mediated by plasmid conjugation and/or transposon jumps. Environmental disinfection by quaternary ammonium-based disinfectant and replacement of contaminated equipment failed to eradicate environmental sources. Interestingly, efflux pumps genes conferring resistance to quaternary ammonium compounds were widespread in the isolates. As removing sinks was not feasible, a combination of a foaming product degrading the biofilm and foaming disinfectant based on peracetic acid and hydrogen peroxide has been evaluated and has so far prevented re-colonisation of the proximal sink drain by CPO. The persistence in the hospital environment of antibiotic-and-disinfectant resistant bacteria with the ability to transfer mobile genetic elements poses a serious threat on ICU patients with a risk of shifting towards an endemicity scenario. Innovative strategies are needed to address persistent environmental reservoirs and prevent CPO transmission.

Update on potential interventions to reduce the risk for transmission of health care-associated pathogens from floors and sinks

Health care facility floors and sink drains and other wastewater drainage sites are universally contaminated with potential pathogens and there are plausible mechanisms by which organisms can be disseminated from these sites. However, floors and sink drains are not addressed as potential sources of pathogen transmission in most health care facilities. One factor that has hindered progress in addressing floors and sinks has been the lack of practical and effective measures to reduce the risk for dissemination of organisms from these sites. This article provides an update on some of the potential interventions being used to reduce the risk for transmission of health care-associated pathogens from floors and sinks. Practical approaches to address these sites of contamination are emphasized.

Evaluation of antibiotic-resistant bacteria in home kitchens and bathrooms: Is there a link between home disinfectant use and antibiotic resistance?

To determine the relationship between home disinfectant use and the prevalence of antibiotic resistance among environmental isolates of human pathogens. Bacteria were cultured from 5 kitchen and 5 bathroom sites using quantitative methods. Antibiotic susceptibility was determined by standard methods. Home disinfectant use was assessed via a questionnaire. The overall total mean log10 counts (total CFU) for the kitchen and bathroom were 4.31 and 4.88, respectively. Gram-positive bacteria were more common in the bathroom (4.05) than in the kitchen (3.60), while Gram-negative bacilli were more common in the kitchen (4.23) than in the bathroom (3.86). The sink and bath drains were the most contaminated sites with 6.16-log10 of total CFU and 6.6-log10 in the kitchen and bathroom, respectively. Households reported cleaning frequency with a variety of commercial products. Most respondents used antibacterial products (eg, soaps, surface disinfectants) in the home. Antibiotic-resistant pathogens were infrequently isolated in the homes evaluated. Compared to pathogens causing community-acquired clinical infections in the ICARE study, pathogens isolated from households are less likely to demonstrate antibiotic resistance. In addition, no relationship between antibacterial use or frequency of cleaning or disinfection and antibiotic resistance was revealed.

RECYCLING OF OIL USED FOR THE PRODUCTION OF HANDMADE LIQUID SOAP AS AN EXPERIMENTAL ACTIVITY IN CHEMISTRY

This article aims to carry out a reflective analysis on the production process of homemade liquid soap from the waste of cooking oil generated. Every day, it becomes more evident to the population how much the commitment we must have with the care of the environment is necessary, as there are a number of problems that oppose the existence of a healthy environment, among these are those arising from the practices of everyday life such as the poor disposal of cooking oil after use, whose final destination, in most cases, are sink drains, causing their clogging, the gullets of large urban centers, damaging the bodies of water and causing in environmental problems such as pollution of the aquatic environment and economic losses such as the increase in the cost of processes in effluent treatment plants. Through this practical-experimental activity, it is understood that teaching Chemistry through experimentation develops logical reasoning, stimulates thinking, creativity and the ability to resolve situations related to the content, which will be linked to the reality of everyday life there. students, from a formative and citizen perspective. In addition, making use of an approach that involves current issues and content of general interest, it helps the student to understand Chemistry in its daily applications, awakening him to value the sciences and motivating him to search for new knowledge.

Sink Drains in a Neonatal Intensive Care Unit: A Retrospective Risk Assessment and Evaluation.

Water systems in health care facilities can form reservoirs for Gram-negative bacteria. While planning a new neonatal intensive care unit (NICU), we performed a retrospective evaluation of potential risks from water-diverting systems on the existing NICU of our tertiary care University Hospital. During 2017 to 2023, we recorded nine nosocomial cluster events with bacterial pathogens in our NICU. Of these, three clusters of Gram-negative bacteria were potentially related to sink drains: A Klebsiella oxytoca, a Pseudomonas aeruginosa, and an Enterobacter hormaechei cluster were uncovered by clinical routine screening of patients and breastmilk samples. They were confirmed using whole-genome sequencing and a subsequent core genome multilocus sequence typing (cgMLST) algorithm. Our observations highlight that the implementation of sink drains in a NICU may have negative effects on patients' safety. Construction planning should concentrate on the avoidance of washbasins in patient rooms when redesigning sensitive areas such as NICUs.

Cluster of Carbapenemase-Producing Carbapenem-Resistant Pseudomonas aeruginosa Among Patients in an Adult Intensive Care Unit - Idaho, 2021-2022.

Treatment of carbapenemase-producing carbapenem-resistant Pseudomonas aeruginosa (CP-CRPA) infections is challenging because of antibiotic resistance. CP-CRPA infections are highly transmissible in health care settings because they can spread from person to person and from environmental sources such as sink drains and toilets. During September 2021-January 2022, an Idaho hospital (hospital A) isolated CP-CRPA from sputum of two patients who stayed in the same intensive care unit (ICU) room (room X), 4 months apart. Both isolates had active-on-imipenem metallo-beta-lactamase (IMP) carbapenemase gene type 84 (blaIMP-84) and were characterized as multilocus sequence type 235 (ST235). A health care-associated infections team from the Idaho Division of Public Health visited hospital A during March 21-22, 2022, to discuss the cluster investigation with hospital A staff members and to collect environmental samples. CP-CRPA ST235 with blaIMP-84 was isolated from swab samples of one sink in room X, suggesting it was the likely environmental source of transmission. Recommended prevention and control measures included application of drain biofilm disinfectant, screening of future patients who stay in room X (e.g., the next 10 occupants) upon reopening, and continuing submission of carbapenem-resistant P. aeruginosa (CRPA) isolates to public health laboratories. Repeat environmental sampling did not detect any CRPA. As of December 2022, no additional CP-CRPA isolates had been reported by hospital A. Collaboration between health care facilities and public health agencies, including testing of CRPA isolates for carbapenemase genes and implementation of sink hygiene interventions, was critical in the identification of and response to this CP-CRPA cluster in a health care setting.

Sink Drain Survey of Carbapenemase-Producing Organisms at a Kentucky Academic Medical Center

Sink Drain Survey of Carbapenemase-Producing Organisms at a Kentucky Academic Medical Center

Sanitary installations and wastewater plumbing as reservoir for the long-term circulation and transmission of carbapenemase producing Citrobacter freundii clones in a hospital setting

BackgroundAccumulating evidence shows a role of the hospital wastewater system in the spread of multidrug-resistant organisms, such as carbapenemase producing Enterobacterales (CPE). Several sequential outbreaks of CPE on the geriatric ward of the Ghent University hospital have led to an outbreak investigation. Focusing on OXA-48 producing Citrobacter freundii, the most prevalent species, we aimed to track clonal relatedness using whole genome sequencing (WGS). By exploring transmission routes we wanted to improve understanding and (re)introduce targeted preventive measures.MethodsEnvironmental screening (toilet water, sink and shower drains) was performed between 2017 and 2021. A retrospective selection was made of 53 Citrobacter freundii screening isolates (30 patients and 23 environmental samples). DNA from frozen bacterial isolates was extracted and prepped for shotgun WGS. Core genome multilocus sequence typing was performed with an in-house developed scheme using 3,004 loci.ResultsThe CPE positivity rate of environmental screening samples was 19.0% (73/385). Highest percentages were found in the shower drain samples (38.2%) and the toilet water samples (25.0%). Sink drain samples showed least CPE positivity (3.3%). The WGS data revealed long-term co-existence of three patient sample derived C. freundii clusters. The biggest cluster (ST22) connects 12 patients and 8 environmental isolates taken between 2018 and 2021 spread across the ward. In an overlapping period, another cluster (ST170) links eight patients and four toilet water isolates connected to the same room. The third C. freundii cluster (ST421) connects two patients hospitalised in the same room but over a period of one and a half year. Additional sampling in 2022 revealed clonal isolates linked to the two largest clusters (ST22, ST170) in the wastewater collection pipes connecting the rooms.ConclusionsOur findings suggest long-term circulation and transmission of carbapenemase producing C. freundii clones in hospital sanitary installations despite surveillance, daily cleaning and intermittent disinfection protocols. We propose a role for the wastewater drainage system in the spread within and between rooms and for the sanitary installations in the indirect transmission via bioaerosol plumes. To tackle this problem, a multidisciplinary approach is necessary including careful design and maintenance of the plumbing system.