Exploring toilet plume bioaerosol exposure dynamics in public toilets using a Design of Experiments approach.

Bioaerosols generated during toilet flushing can contribute to the spread of airborne pathogens and cross-contamination in indoor environments. This presents an increased risk of fomite-mediated or aerosol disease transmission. This study systematically investigated the factors contributing to increased bioaerosol exposure following toilet flushing and developed an empirical model for predicting the exposure-relevant bioaerosol concentration. Air in a toilet cubicle was sampled by impaction after seeding with Clostridium difficile spores. Design of Experiments (DoE) main effects screening and full factorial design approaches were then employed to investigate the significant factors that heighten the risk of exposure to bioaerosols post-flush. Our findings reveal that the inoculated bacterial concentration (C), time elapsed after flushing (t), lateral distance (d), and mechanical ventilation (v) are significant predictors of bioaerosol concentration, with p-values < 0.05. The interaction term, C × d showed a marked increase in bioaerosol concentration up to 232 CFU/m3 at the closest proximity and highest pathogen load. The interplay of C and t (C × t) demonstrated a time-dependent attenuation of bioaerosol viability, with concentrations peaking at 241 CFU/m3 immediately post-flush and notably diminishing over time. The lateral distance and time post-flush (d × t) interaction also revealed a gradual decrease in bioaerosol concentration, highlighting the effectiveness of spatial and temporal dilution in mitigating bioaerosol exposure risks. Furthermore, there is an immediate rise in relative humidity levels post-flush, impacting the air quality in the toilet environment. This study not only advances our understanding of exposure pathways in determining bioaerosol exposure, but also offers pivotal insights for designing targeted interventions to reduce bioaerosol exposure. Recommendations include designing public toilets with antimicrobial surfaces, optimizing ventilation, and initiating timely disinfection protocols to prioritise surfaces closest to the toilet bowl during peak exposure periods, thereby promoting healthier indoor environments and safeguarding public health in high-traffic toilet settings.

A biogeographic 16S rRNA survey of bacterial communities of ureolytic biomineralization from California public restrooms.

In this study, we examined the total bacterial community associated with ureolytic biomineralization from urine drainage systems. Biomineral samples were obtained from 11 California Department of Transportation public restrooms fitted with waterless, low-flow, or conventional urinals in 2019. Following high throughput 16S rRNA Illumina sequences processed using the DADA2 pipeline, the microbial diversity assessment of 169 biomineral and urine samples resulted in 3,869 reference sequences aggregated as 598 operational taxonomic units (OTUs). Using PERMANOVA testing, we found strong, significant differences between biomineral samples grouped by intrasystem sampling location and urinal type. Biomineral microbial community profiles and alpha diversities differed significantly when controlling for sampling season. Observational statistics revealed that biomineral samples obtained from waterless urinals contained the largest ureC/16S gene copy ratios and were the least diverse urinal type in terms of Shannon indices. Waterless urinal biomineral samples were largely dominated by the Bacilli class (86.1%) compared to low-flow (41.3%) and conventional samples (20.5%), and had the fewest genera that account for less than 2.5% relative abundance per OTU. Our findings are useful for future microbial ecology studies of urine source-separation technologies, as we have established a comparative basis using a large sample size and study area.

Droplets generated from toilets during urination as a possible vehicle of carbapenem-resistant Klebsiella pneumoniae.

BACKGROUND: In the health care setting, infection control actions are fundamental for containing the dissemination of multidrug-resistant bacteria (MDR). Carbapenemase-producing Enterobacterales (CPE), especially Klebsiella pneumoniae (CR-KP), can spread among patients, although the dynamics of transmission are not fully known. Since CR-KP is present in wastewater and microorganisms are not completely removed from the toilet bowl by flushing, the risk of transmission in settings where toilets are shared should be addressed. We investigated whether urinating generates droplets that can be a vehicle for bacteria and explored the use of an innovative foam to control and eliminate this phenomenon. METHODS: To study droplet formation during urination, we set up an experiment in which different geometrical configurations of toilets could be reproduced and customized. To demonstrate that droplets can mobilize bacteria from the toilet bowl, a standard ceramic toilet was contaminated with a KPC-producing Klebsiella pneumoniae ST101 isolate. Then, we reproduced urination and attached culture dishes to the bottom of the toilet lid for bacterial colony recovery with and without foam. RESULTS: Rebound droplets invariably formed, irrespective of the geometrical configuration of the toilet. In microbiological experiments, we demonstrated that bacteria are always mobilized from the toilet bowl (mean value: 0.11 ± 0.05 CFU/cm2) and showed that a specific foam layer can completely suppress mobilization. CONCLUSIONS: Our study demonstrated that droplets generated from toilets during urination can be a hidden source of CR-KP transmission in settings where toilets are shared among colonized and noncolonized patients.

Bathroom contamination by antibiotic-resistant Enterobacterales (ESBLPE and CPE): an experimental study.

BACKGROUND: Extended-spectrum ß-lactamase-producing Enterobacterales (ESBLPE) and carbapenemase-producing Enterobacterales (CPE) cause serious infections. Their presence in urine may lead to environmental contamination potentially responsible for cross-transmission. AIM: To evaluate the level of spraying and contamination after emptying urine in the toilet and rinsing in the sink, a common practice in the healthcare setting. METHODS: For each test, the procedure was similar: seat raised, emptying urinal bottle into the toilet at the height of the bowl, rinsing in the sink and flushing. To study splash-drops, water and fluorescein were mixed in the urinal bottle. In each area, the splash-drops frequency and level were assessed with UV. To study contamination, three ESBLPE and one CPE were diluted in saline, 106/mL. Contamination was assessed by sampling before, immediately after and 3 h after the test. The swabs were cultured and the colonies counted and identified. FINDINGS: The areas at the highest risk of spraying were the toilet bowl contour (N = 36/36), the underside of the toilet seat (N = 34) and the inside of the sink (N = 34). Except for gloves (N = 14), there was low clothing contamination. The most frequently contaminated areas were inside the sink (40/48), where the highest levels of contamination were found (14/48). CONCLUSION: Emptying the urinal bottles in the toilet followed by sink rinsing is associated with a significant risk of projection and contamination, depending on the area (highest risk at the sink), but the bacteria did not survive beyond 3 h. This practice, which carries a risk of cross-transmission, should be reviewed.

Toilet drain water as a potential source of hospital room-to-room transmission of carbapenemase-producing Klebsiella pneumoniae.

BACKGROUND: Carbapenemase-producing Enterobacterales (CPE) have rapidly emerged in Europe, being responsible for nosocomial outbreaks. AIM: Following an outbreak in the burn unit of Ghent University Hospital, we investigated whether CPE can spread between toilets through drain water and therefrom be transmitted to patients. METHODS: In 2017, the burn centre of our hospital experienced an outbreak of OXA-48-producing Klebsiella pneumoniae that affected five patients staying in three different rooms. Environmental samples were collected from the sink, shower, shower stretcher, hand rail of the bed, nursing carts, toilets, and drain water to explore a common source. Whole-genome sequencing and phylogenetic analysis was performed on K. pneumoniae outbreak isolates and two random K. pneumoniae isolates. FINDINGS: OXA-48-producing K. pneumoniae was detected in toilet water in four out of six rooms and drain water between two rooms. The strain persisted in two out of six rooms after two months of daily disinfection with bleach. All outbreak isolates belonged to sequence type (ST) 15 and showed isogenicity (<15 allele differences). This suggests that the strain may have spread between rooms by drain water. Unexpectedly, one random isolate obtained from a patient who became colonized while residing at the geriatric ward clustered with the outbreak isolates, suggesting the outbreak to be larger than expected. Daily application of bleach tended to be superior to acetic acid to disinfect toilet water; however, disinfection did not completely prevent the presence of carbapenemase-producing K. pneumoniae in toilet water. CONCLUSION: Toilet drain water may be a potential source of hospital room-to-room transmission of carbapenemase-producing K. pneumoniae.

Bioaerosols generated from toilet flushing in rooms of patients with Clostridioides difficile infection.

BACKGROUND: Clostridioides difficile infection (CDI) is the most frequently reported hospital-acquired infection in the United States. Bioaerosols generated during toilet flushing are a possible mechanism for the spread of this pathogen in clinical settings. OBJECTIVE: To measure the bioaerosol concentration from toilets of patients with CDI before and after flushing. DESIGN: In this pilot study, bioaerosols were collected 0.15 m, 0.5 m, and 1.0 m from the rims of the toilets in the bathrooms of hospitalized patients with CDI. Inhibitory, selective media were used to detect C. difficile and other facultative anaerobes. Room air was collected continuously for 20 minutes with a bioaerosol sampler before and after toilet flushing. Wilcoxon rank-sum tests were used to assess the difference in bioaerosol production before and after flushing. SETTING: Rooms of patients with CDI at University of Iowa Hospitals and Clinics. RESULTS: Bacteria were positively cultured from 8 of 24 rooms (33%). In total, 72 preflush and 72 postflush samples were collected; 9 of the preflush samples (13%) and 19 of the postflush samples (26%) were culture positive for healthcare-associated bacteria. The predominant species cultured were Enterococcus faecalis, E. faecium, and C. difficile. Compared to the preflush samples, the postflush samples showed significant increases in the concentrations of the 2 large particle-size categories: 5.0 µm (P = .0095) and 10.0 µm (P = .0082). CONCLUSIONS: Bioaerosols produced by toilet flushing potentially contribute to hospital environmental contamination. Prevention measures (eg, toilet lids) should be evaluated as interventions to prevent toilet-associated environmental contamination in clinical settings.

Contamination of Common Area and Rehabilitation Gym Environment with Multidrug-Resistant Organisms.

OBJECTIVES: To quantify the multidrug-resistant organism (MDRO) burden of high-touch common area and rehabilitation gym surfaces, and to assess microorganism transfer potential during rehabilitation sessions. DESIGN: Prospective study of environmental contamination. SETTING: Nursing home (NH). PARTICIPANTS: Six Michigan NHs. MEASUREMENTS: Monthly samples from common area surfaces (eg, living room), rehabilitation equipment, and rehabilitation personnel hands were screened for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and resistant gram-negative bacilli (R-GNB). To assess microorganism transfer potential, we conducted an in-depth assessment of microorganism transfer during 10 rehabilitation sessions. Microorganism transfer was defined as the identification of a microorganism on a destination surface that was uncontaminated before the rehabilitation session. Patient frequency of common area usage was also assessed qualitatively. RESULTS: We obtained 1338 common area specimens from 180 monthly facility visits, of which 13.4% (179/1338) were MDRO positive: MRSA, 3.8%; VRE, 5.8%; and R-GNB, 5.1%. A total of 64% (116/180) of sampling visits had at least one MDRO-positive common area specimen. Within rehabilitation gyms, we obtained 521 equipment and 190 personnel hand specimens during 60 monthly visits. Of the equipment specimens collected, 7.7% (40/521) were MDRO positive: MRSA, 2.5%; VRE, 4.0%; and R-GNB, 1.9%. Of the 190 rehabilitation personnel hand specimens collected, 3.7% (7/190) were MDRO positive. Overall, 55% (33/60) of rehabilitation gym visits had at least one MDRO-positive specimen. Microorganism transfer assessment during 10 rehabilitation sessions revealed 35 opportunities for transfer during which microorganism transfer occurred in 17.1% (6/35) of opportunities. CONCLUSION: NH common areas and rehabilitation gyms are MDRO reservoirs that may contribute to the transmission of healthcare-associated pathogens. Because NHs accommodate the increasing short-stay patient population, developing effective interventions that reduce MDRO transmission in the common area and rehabilitation gym environment should be considered an infection prevention priority. J Am Geriatr Soc 68:478-485, 2020.

Molecular characterization and antimicrobial susceptibility of bacterial isolates present in tap water of public toilets.

BACKGROUND: The present study was carried out to investigate the tap water quality of public toilets in Amritsar, Punjab, India. METHODS: Water samples from the taps of the public toilets were collected in sterile containers and physicochemical and bacteriological analysis was performed using standard methods. Also, genotypic and phenotypic characterization of the bacterial isolates was performed using different biochemical tests and 16S ribosomal RNA analysis. An antibiotic susceptibility test was performed using antibiotics based on their mode of action. A biofilm assay was performed to assess the adhesion potential of the isolates. RESULTS: A total of 25 bacterial isolates were identified from the water samples, including Acinetobacter junii, Acinetobacter pittii, Acinetobacter haemolyticus, Bacillus pumilus, Bacillus megaterium, Bacillus marisflavi, Bacillus flexus, Bacillus oceanisediminis, Pseudomonas otitidis, Pseudomonas sp. RR013, Pseudomonas sp. RR021, Pseudomonas sp. RR022, Escherichia coli and Enterobacter cloacae. The results of the antimicrobial susceptibility test revealed that the antibiotics cefodroxil, aztreonam, nitrofurantoin, cefepime, ceftazidime and amoxyclav were found to be mostly ineffective against various isolates. The biofilm assay revealed the weak, moderate and strong biofilm producers among them. CONCLUSIONS: The tap water in the public toilets was microbially contaminated and needs to be monitored carefully. The antibiotic susceptibility profile showed that of 25 bacterial isolates, 5 were multidrug resistant. Bacterial isolates exhibited strong to weak adhesion potential in the biofilm assay.

Antibiotic resistant bacteria and resistance genes in biofilms in clinical wastewater networks.

Increasing isolation rates of resistant bacteria in the last years require identification of potential infection reservoirs in healthcare facilities. Especially the clinical wastewater network represents a potential source of antibiotic resistant bacteria. In this work, the siphons of the sanitary installations from 18 hospital rooms of two German hospitals were examined for antibiotic resistant bacteria and antibiotic residues including siphons of showers and washbasins and toilets in sanitary units of psychosomatic, haemato-oncological, and rehabilitation wards. In addition, in seven rooms of the haemato-oncological ward, the effect of 24 h of stagnation on the antibiotic concentrations and MDR (multi-drug-resistant) bacteria in biofilms was evaluated. Whereas no antibiotic residues were found in the psychosomatic ward, potential selective concentrations of piperacillin, meropenem and ciprofloxacin were detected at a rehabilitation ward and ciprofloxacin and trimethoprim were present at a haemato-oncology ward. Antibiotic resistant bacteria were isolated from the siphons of all wards, however in the psychosomatic ward, only one MDR strain with resistance to piperacillin, third generation cephalosporins and quinolones (3MRGN) was detected. In contrast, the other two wards yielded 11 carbapenemase producing MDR isolates and 15 3MRGN strains. The isolates from the haemato-oncological ward belonged mostly to two specific rare sequence types (ST) (P. aeruginosa ST823 and Enterobacter cloacae complex ST167). In conclusion, clinical wastewater systems represent a reservoir for multi-drug-resistant bacteria. Consequently, preventive and intervention measures should not start at the wastewater treatment in the treatment plant, but already in the immediate surroundings of the patient, in order to minimize the infection potential.

Toilet plume aerosol generation rate and environmental contamination following bowl water inoculation with Clostridium difficile spores.

INTRODUCTION: Clostridium difficile is the leading cause of health care-associated gastric illness. Environmental contamination with C difficile spores is a risk factor for contact transmission, and toilet flushing causes such contamination. This work explores toilet contamination persistence and environmental contamination produced over a series of flushes after contamination. METHODS: A flushometer toilet was seeded with C difficile spores in a sealed chamber. The toilet was flushed 24times, with postflush bowl water samples and settle plates periodically collected for culturing and counting. Air samples were collected after each of 12 flushes using rotating plate impactors. RESULTS: Spores were present in bowl water even after 24 flushes. Large droplet spore deposition accumulated over the 24-flush period. Droplet nuclei spore bioaerosol was produced over at least 12 flushes. CONCLUSIONS: Toilets contaminated with C difficile spores are a persistent source of environmental contamination over an extended number of flushes.

Environmental Panels as a Proxy for Nursing Facility Patients With Methicillin-Resistant Staphylococcus aureus and Vancomycin-Resistant Enterococcus Colonization.

Background: Most nursing facilities (NFs) lack methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) surveillance programs due to limited resources and high costs. We investigated the utility of environmental screening of high-touch surfaces in patient rooms as a way to circumvent these challenges. Methods: We compared MRSA and VRE culture data from high-touch surfaces in patients' rooms (14450 samples from 6 NFs) and ranked each site's performance in predicting patient colonization (7413 samples). The best-performing sites were included in a MRSA- and a VRE-specific panel that functioned as a proxy for patient colonization. Molecular typing was performed to confirm available concordant patient-environment pairs. Results: We identified and validated a MRSA panel that consisted of the bed controls, nurse call button, bed rail, and TV remote control. The VRE panel included the toilet seat, bed controls, bed rail, TV remote control, and top of the side table. Panel colonization data tracked patient colonization. Negative predictive values were 89%-92% for MRSA and 82%-84% for VRE. Molecular typing confirmed a strong clonal type relationship in available concordant patient-environment pairs (98% for MRSA, 91% for VRE), pointing to common epidemiological patterns for environmental and patient isolates. Conclusions: Environmental panels used as a proxy for patient colonization and incorporated into facility surveillance protocols can guide decolonization strategies, improve awareness of MRSA and VRE burden, and inform efforts to reduce transmission. Targeted environmental screening may be a viable surveillance strategy for MRSA and VRE detection in NFs.

Intensive Care Unit Wastewater Interventions to Prevent Transmission of Multispecies Klebsiella pneumoniae Carbapenemase-Producing Organisms.

Background: The increasing prevalence of nosocomial carbapenemase-producing Enterobacteriaceae is a concern. However, the role of the environment in multispecies outbreaks remains poorly understood. There is increasing recognition that hospital wastewater plumbing may play a role. Methods: Covers were installed on all hoppers (a "toilet-like" waste disposal system) in adult intensive care units (ICUs) of a university hospital; additionally in the surgical ICU, sink trap heating and vibration devices were also installed. Patient acquisitions of Klebsiella pneumoniae carbapenemase-producing organisms (KPCOs) for patients who were admitted to an intervention unit were compared for 18-month preintervention and intervention periods. Results: Sixty hopper covers and 23 sink trap devices were installed. Fifty-six new multispecies KPCO acquisitions occurred preintervention compared to 30 during the intervention. Decreases for all KPCO acquisitions (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.31-0.81; P = .003) and KPCO-positive clinical cultures (OR, 0.29; 95% CI, 0.17-0.48; P < .001) per admission in patients exposed to an intervention unit were observed. The incidence rate ratio was 0.51-fold (95% CI, 0.43-0.61) lower for all KPCO acquisitions during the intervention. The effect of the sink trap devices alone could not be determined, although the proportion of sink drain cultures positive for KPCO decreased (12/15 [80%] sites sampled preintervention vs 40/840 [5%] sampled during the intervention; P = .001). Conclusions: An intervention targeting wastewater plumbing fixtures, by installation of hopper covers, demonstrated a decrease in patient KPCO acquisitions. Considering wastewater reservoirs in nosocomial transmission of multispecies carbapenemase-producing Enterobacteriaceae may be critical.

Occurrence of Legionella in UK household showers.

Household water systems have been proposed as a source of sporadic, community acquired Legionnaires' disease. Showers represent a frequently used aerosol generating device in the domestic setting yet little is known about the occurrence of Legionella spp. in these systems. This study has investigated the prevalence of Legionella spp. by culture and qPCR in UK household showers. Ninety nine showers from 82 separate properties in the South of England were sampled. Clinically relevant Legionella spp. were isolated by culture in 8% of shower water samples representing 6% of households. Legionella pneumophila sg1 ST59 was isolated from two showers in one property and air sampling demonstrated its presence in the aerosol state. A further 31% of showers were positive by Legionella spp. qPCR. By multi-variable binomial regression modelling Legionella spp. qPCR positivity was associated with the age of the property (p=0.02), the age of the shower (p=0.01) and the frequency of use (p=0.09). The concentration of Legionella spp. detected by qPCR was shown to decrease with increased frequency of use (p=0.04) and more frequent showerhead cleaning (p=0.05). There was no association between Legionella spp. qPCR positivity and the cold water supply or the showerhead material (p=0.65 and p=0.71, respectively). Household showers may be important reservoirs of clinically significant Legionella and should be considered in source investigations. Simple public health advice may help to mitigate the risk of Legionella exposure in the domestic shower environment.

Reproducible elimination of Clostridium difficile spores using a clinical area washer disinfector in 3 different health care sites.

BACKGROUND: Following a Clostridium difficile infection outbreak, the Infection Prevention and Control team at our institution queried the risk of transmission via bedpans reprocessed in washer disinfectors (WDs). This study's objective was to determine the effectiveness of the mechanical action, detergent, and temperature on the eradication of C difficile spores in 1 type of WD model. MATERIALS AND METHODS: Three types of reusable bedpans/pots were inoculated with sterile human feces that contained 1 × 10(7) CFU/mL C difficile spores. The 0.3 mL fecal-spore suspension was inoculated in sealed cryovials. These items were reprocessed using the longest wash cycle of WDs in 9 clinical units, and then tested for residual C difficile spores. The number of colonies on each replicate organism detection and counting plate was recorded after anaerobic incubation at 35°C for 48 hours, and the log reduction was calculated. RESULTS: All 9 WDs met the manufacturer's operational specifications. Forty-three (96%) of 45 bedpans had no viable spores (>5.9 log10C difficile spore reduction). Two bedpans had 1 to 2 spores remaining. Viable C difficile spores were isolated from all 9 cryovials. DISCUSSION AND CONCLUSIONS: Results demonstrated that when operating the WD as stipulated, C difficile spores were satisfactorily eliminated from bedpan surfaces. Temperature alone was insufficient to kill C difficile spores. It also suggested the importance of staff training, machine maintenance, and WD purchase specifications.