The Hospital Water Environment as a Reservoir for Carbapenem-Resistant Organisms Causing Hospital-Acquired Infections-A Systematic Review of the Literature

Molecular surveillance of carbapenem-resistant Enterobacterales in two nearby tertiary hospitals to identify regional spread of high-risk clones in Germany, 2019-2020

BACKGROUND

Understanding the transmission dynamics of carbapenem-resistant Enterobacterales (CRE) is critical to addressing the escalating global threat of antimicrobial resistance (AMR). Although hospital transmission of CRE has been extensively studied, information on community transmission is lacking.

AIM

To identify genomic clusters of CRE from two nearby institutions that may be indicative of community or inter-facility transmission.

METHODS

CRE isolates between January 1st, 2019 and December 31st, 2020 from two tertiary hospitals, detected in the respective routine microbiology laboratories, were collected and characterized by short-read whole-genome sequencing.

FINDINGS

A total of 272 CRE were collected, with Enterobacter cloacae complex (71/192, 37%) predominant in Heidelberg and Escherichia coli (19/80, 24%) in Mannheim. The most common carbapenem resistance gene, blaOXA-48, was detected in 38% of CRE from both centres. Several putative transmission clusters were found, including six clusters of E. cloacae complex, five clusters of Klebsiella pneumoniae, four clusters of Citrobacter freundii, and two clusters each of Escherichia coli and K. aerogenes. No clusters involved isolates from both study centres, except for an ST22 C. freundii cluster. Globally circulating clones were identified between the two centres for ST131 E. coli, ST66 E. hormaechei, and ST22 C. freundii.

CONCLUSION

This study found no widespread transmission clusters among isolates from both centres, suggesting a hospital-specific clonal structure. This suggests that CRE clusters involving both institutions may indicate emerging or circulating clones in the community, highlighting the need for intersectoral surveillance and data sharing.

Carbapenemase-producing Enterobacterales isolated from hospital sinks: molecular relationships with isolates from patients and the change in contamination status after daily disinfection with sodium hypochlorite

Objective

This study aimed to investigate the contamination status of hospital sinks with carbapenemase-producing Enterobacterales (CPE), the efficacy of daily cleaning with sodium hypochlorite, and the relationships between CPEs isolated from contaminated sinks and patients.

Design

Pre/postintervention surveys of the CPE-contaminated sinks.

Setting

Hospital wards including pediatric intensive care unit in a children's hospital.

Participants

Consenting CPE-colonized patients admitted between November 2018 and June 2021 in our hospital.

Methods

Environmental culture of 180 sinks from nine wards in our hospital was performed three times with an interval of 2 years (2019, 2021, 2023). Molecular typing of the isolated strains from the sinks and patients was performed. After the first surveillance culture, we initiated daily disinfection of the sinks using sodium hypochlorite.

Results

Before the intervention, we detected 30 CPE-positive sinks in 2019. After the intervention with sodium hypochlorite, we observed a substantial decline in the number of sinks contaminated with CPE; 13 in 2021 and 6 in 2023. However, the intervention did not significantly reduce the number of CPE-contaminated sinks used for the disposal of nutrition-rich substances. The CPE isolates from the patients and those from the sinks of the wards or floors where they were admitted tended to have similar pulse-field gel electrophoresis patterns.

Conclusion

Contaminated sinks could be reservoirs of disseminating CPE to the patients. Daily disinfection of sinks with sodium hypochlorite may be effective in eliminating CPE, although the effect could be weaker in sinks with a greater risk of contact with nutrition-rich substances.

Retrospective genome-oriented analysis reveals low transmission rate of multidrug-resistant Pseudomonas aeruginosa from contaminated toilets at a bone marrow transplant unit

BACKGROUND

Prevention of toilet-to-patient transmission of multidrug-resistant Pseudomonas aeruginosa (MDR PA) poses management-related challenges at many bone marrow transplant units (BMTU). Using whole-genome sequencing (WGS), we conducted a longitudinal retrospective analysis of the toilet-to-patient transmission rate for MDR PA under existing infection control (IC) measures at a BMTU with persistent MDR PA toilet colonization.

METHODS

The local IC bundle comprised 1.) patient education regarding IC, 2.) routine patient screening, 3.) toilet flushing volume of 9L, 4.) bromination of toilet water tanks, and 5.) toilet decontamination using hydrogen peroxide. Toilet water was sampled periodically between 2016-2021 (minimum every three months - 26 intervals). Upon MDR PA detection, disinfection and re-sampling were repeated until ≤ 3 cfu/100ml was reached. WGS was performed retrospectively on all available MDR PA isolates (90 of 117 positive environmental samples, 10 of 14 patients - including nine nosocomial).

RESULTS

WGS of patient isolates identified six sequence types (STs), with ST235/CT1352/FIM-1 and ST309/CT3049/no-carbapenemase being predominant (three isolates each). Environmental sampling consistently identified MDR PA ST235 (65.5% ST235/CT1352/FIM-1), showing low genetic diversity (difference of ≤29 alleles by cgMLST). This indicates that direct toilet-to-patient transmission was infrequent although MDR PA was widespread (detection on 79 occasions, detection in every toilet). Only three MDR PA patient isolates can be attributed to the ST235/CT1352/FIM-1 toilet MRD PA population over six years.

CONCLUSIONS

Genome-oriented environmental and patient surveillance suggests that the persistent presence of MDR PA poses a potential risk for acquisition, but with stringent targeted toilet disinfection, only three highly vulnerable patients experienced nosocomial transmission.

Nosocomial outbreak caused by disinfectant-resistant Serratia marcescens in an adult intensive care unit, Hungary, February to March 2022

In 2022, an outbreak with severe bloodstream infections caused by Serratia marcescens occurred in an adult intensive care unit (ICU) in Hungary. Eight cases, five of whom died, were detected. Initial control measures could not stop the outbreak. We conducted a matched case-control study. In univariable analysis, the cases were more likely to be located around one sink in the ICU and had more medical procedures and medications than the controls, however, the multivariable analysis was not conclusive. Isolates from blood cultures of the cases and the ICU environment were closely related by whole genome sequencing and resistant or tolerant against the quaternary ammonium compound surface disinfectant used in the ICU. Thus, S. marcescens was able to survive in the environment despite regular cleaning and disinfection. The hospital replaced the disinfectant with another one, tightened the cleaning protocol and strengthened hand hygiene compliance among the healthcare workers. Together, these control measures have proved effective to prevent new cases. Our results highlight the importance of multidisciplinary outbreak investigations, including environmental sampling, molecular typing and testing for disinfectant resistance.

A narrative review and update on drain related outbreaks

BACKGROUND

Outbreaks linked to hospital drainage systems are well reported and continue to present challenges to incident management teams. Such outbreaks can be protracted and complex, with multi-modal strategies being required for remediation.

AIM

The aim was to summarise recent drain related outbreaks, investigate whether multimodal control measures are being implemented and determine any antecedent factors.

METHODS

Databases were searched for drain related outbreaks over a five-year period. Search terms employed included healthcare drainage outbreaks; drain outbreaks;drainage system outbreaks; sink outbreaks; shower outbreaks . Information was collected on country of origin, pathogens involved, unit affected, drain types, patient numbers, drainage system interventions, type of drain disinfectant, infection control interventions, typing method, outcomes and any antecedent factors.

FINDINGS

Nineteen drain related outbreak papers were reviewed. The majority of incidents were due to Carbapenemase producing Enterobacterales (CPE) and were from critical care settings. Most (16/19) recognised the need for a multi-modal approach. Information on the success of interventions was not documented for all but 13/19 reported no further cases after control measures. Variation in the choice of agent and frequency of application exists with regards to drain disinfection. Seven studies discussed antecedent factors.

CONCLUSION

Despite drain related outbreaks being reported for the last 24 years and review articles on the subject, outbreaks continue to pose significant challenges. There is currently no UK guidance on the management of drain related outbreaks or the design of new buildings to mitigate the risk. Addressing the challenges from hospital drainage systems should be considered a priority by agencies and guidance developers.

Genomic investigation of multispecies and multivariant blaNDM outbreak reveals key role of horizontal plasmid transmission

OBJECTIVES

New Delhi metallo-β-lactamases (NDMs) are major contributors to the spread of carbapenem resistance globally. In Australia, NDMs were previously associated with international travel, but from 2019 we noted increasing incidence of NDM-positive clinical isolates. We investigated the clinical and genomic epidemiology of NDM carriage at a tertiary-care Australian hospital from 2016 to 2021.

METHODS

We identified 49 patients with 84 NDM-carrying isolates in an institutional database, and we collected clinical data from electronic medical record. Short- and long-read whole genome sequencing was performed on all isolates. Completed genome assemblies were used to assess the genetic setting of blaNDM genes and to compare NDM plasmids.

RESULTS

Of 49 patients, 38 (78%) were identified in 2019-2021 and only 11 (29%) of 38 reported prior travel, compared with 9 (82%) of 11 in 2016-2018 (P = .037). In patients with NDM infection, the crude 7-day mortality rate was 0% and the 30-day mortality rate was 14% (2 of 14 patients). NDMs were noted in 41 bacterial strains (ie, species and sequence type combinations). Across 13 plasmid groups, 4 NDM variants were detected: blaNDM-1, blaNDM-4, blaNDM-5, and blaNDM-7. We noted a change from a diverse NDM plasmid repertoire in 2016-2018 to the emergence of conserved blaNDM-1 IncN and blaNDM-7 IncX3 epidemic plasmids, with interstrain spread in 2019-2021. These plasmids were noted in 19 (50%) of 38 patients and 35 (51%) of 68 genomes in 2019-2021.

CONCLUSIONS

Increased NDM case numbers were due to local circulation of 2 epidemic plasmids with extensive interstrain transfer. Our findings underscore the challenges of outbreak detection when horizontal transmission of plasmids is the primary mode of spread.

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

BACKGROUND

Pseudomonas aeruginosa (PA) is a common cause of healthcare-associated infection (PA-HAI) in the intensive care unit (ICU).

AIM

To describe the epidemiology of PA-HAI in ICUs in Ontario, Canada, and to identify episodes of sink-to-patient PA transmission.

METHODS

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 ≥48 h 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.

FINDINGS

Over ten months, 72 PA-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.

CONCLUSION

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.

Controlling the hospital aquatic reservoir of multidrug-resistant organisms: a cross-sectional study followed by a nested randomized trial of sink decontamination

OBJECTIVES

The hospital water environment is an important reservoir of multidrug-resistant organisms (MDROs) and presents a risk for patient safety. We assessed the effectiveness of thermal and chemical interventions on sinks contaminated with MDRO in the hospital setting.

METHODS

We conducted a cross-sectional assessment of MDRO contamination of sinks and toilets in 26 clinical wards of a tertiary care hospital. MDRO-contaminated sink traps were then replaced and randomized (1:1:1) to receive chemical (sodium hypochlorite), thermal disinfection (steam), or no intervention. Interventions were repeated weekly for 4 weeks. Sinks were resampled 7 days after the last intervention. The primary outcome was the proportion of decontaminated sinks. MDROs of interest were extended spectrum beta-lactamase (ESBL) producing and carbapenemase-producing Enterobacterales, and non-fermentative Gram-negative bacilli.

RESULTS

In the cross-sectional assessment, at least one MDRO was identified in 258 (36%) of the 748 samples and in 91 (47%) of the 192 water sources. In total, 57 (42%) of the 137 sinks and 34 (62%) of the 55 toilets were contaminated with 137 different MDROs. The most common MDRO were ESBL Enterobacterales (69%, 95/137), followed by Verona Integron-Borne Metallo-β-Lactamase (VIM) carbapenemase producing Pseudomonas aeruginosa (9%, 12/137) and Citrobacter spp. (6%, 5/137). In the nested randomized trial, five of the 16 sinks (31%) in the chemical disinfection group were decontaminated, compared with 8 of 18 (44%) in the control group (OR 0.58; 95% CI, 0.14-2.32) and 9 of 17 (53%) in the thermal disinfection group (OR 1.40; 95% CI, 0.37-5.32).

DISCUSSION

Our study failed to demonstrate an added benefit of repeated chemical or thermal disinfection, beyond changing sink traps, in the MDRO decontamination of sinks. Routine chlorine-based disinfection of sinks may need to be reconsidered.

Hospital water environment and antibiotic use: Key factors in a nosocomial outbreak of carbapenemase-producing Serratia marcescens

BACKGROUND

The healthcare water environment is a potential reservoir of carbapenem-resistant organisms (CROs). Here, we report the role of the water environment as a reservoir and the infection control measures applied to suppress a prolonged outbreak of Klebsiella pneumoniae carbapenemase-producing Serratia marcescens (KPC-SM) in two intensive care units (ICUs).

METHODS

The outbreak occurred in the ICUs of a tertiary hospital from October 2020 to July 2021. Comprehensive patient contact tracing and environmental assessments were conducted, and a case-control study was performed to identify factors associated with the acquisition of KPC-SM. Associations among isolates were assessed via pulsed-field gel electrophoresis (PFGE). Antibiotic usage was analyzed. .

RESULTS

The outbreak consisted of two waves involving a total of 30 patients with KPC-SM. Multiple environmental cultures identified KPC-SM in a sink, a dirty utility room, and a communal bathroom shared by the ICUs, together with the waste bucket of a continuous renal replacement therapy (CRRT) system. The genetic similarity of the KPC-SM isolates from patients and the environment was confirmed by PFGE. A retrospective review of 30 cases identified that the use of CRRT and antibiotics were associated with acquisition of KPC-SM (p < 0.05). There was a continuous increase in the use of carbapenems; notably, the use of colistin has increased since 2019.

CONCLUSION

Our study demonstrates that CRRT systems, along with other hospital water environments, are significant potential sources of resistant microorganisms, underscoring the necessity of enhancing infection control practices in these areas.

The ICU environment contributes to the endemicity of the "Serratia marcescens complex" in the hospital setting

Serratia marcescens is an opportunistic pathogen historically associated with sudden outbreaks in intensive care units (ICUs) and the spread of carbapenem-resistant genes. However, the ecology of S. marcescens populations in the hospital ecosystem remains largely unknown. We combined epidemiological information of 1,432 Serratia spp. isolates collected from sinks of a large ICU that underwent demographic and operational changes (2019-2021) and 99 non-redundant outbreak/non-outbreak isolates from the same hospital (2003-2019) with 165 genomic data. These genomes were grouped into clades (1-4) and subclades (A and B) associated with distinct species: Serratia nematodiphila (1A), S. marcescens (1B), Serratia bockelmannii (2A), Serratia ureilytica (2B), S. marcescens/Serratia nevei (3), and S. nevei (4A and 4B). They may be classified into an S. marcescens complex (SMC) due to the similarity between/within subclades (average nucleotide identity >95%-98%), with clades 3 and 4 predominating in our study and publicly available databases. Chromosomal AmpC β-lactamase with unusual basal-like expression and prodigiosin-lacking species contrasted classical features of Serratia. We found persistent and coexisting clones in sinks of subclades 4A (ST92 and ST490) and 4B (ST424), clonally related to outbreak isolates carrying blaVIM-1 or blaOXA-48 on prevalent IncL/pB77-CPsm plasmids from our hospital since 2017. The distribution of SMC populations in ICU sinks and patients reflects how Serratia species acquire, maintain, and enable plasmid evolution in both "source" (permanent, sinks) and "sink" (transient, patients) hospital patches. The results contribute to understanding how water sinks serve as reservoirs of Enterobacterales clones and plasmids that enable the persistence of carbapenemase genes in healthcare settings, potentially leading to outbreaks and/or hospital-acquired infections.IMPORTANCEThe "hospital environment," including sinks and surfaces, is increasingly recognized as a reservoir for bacterial species, clones, and plasmids of high epidemiological concern. Available studies on Serratia epidemiology have focused mainly on outbreaks of multidrug-resistant species, overlooking local longitudinal analyses necessary for understanding the dynamics of opportunistic pathogens and antibiotic-resistant genes within the hospital setting. This long-term genomic comparative analysis of Serratia isolated from the ICU environment with isolates causing nosocomial infections and/or outbreaks within the same hospital revealed the coexistence and persistence of Serratia populations in water reservoirs. Moreover, predominant sink strains may acquire highly conserved and widely distributed plasmids carrying carbapenemase genes, such as the prevalent IncL-pB77-CPsm (pOXA48), persisting in ICU sinks for years. The work highlights the relevance of ICU environmental reservoirs in the endemicity of certain opportunistic pathogens and resistance mechanisms mainly confined to hospitals.

Carbapenem- and colistin-resistant Enterobacterales in intensive care unit patients in Mediterranean countries, 2019

Introduction

The colonization of patients by carbapenemase-producing Enterobacterales (CPE) has been associated with heightened mortality, especially in vulnerable individuals within intensive care units (ICUs). Our study aimed to comprehensively assess CPE prevalence among ICU patients across the Mediterranean region pre-COVID-19, conducting a multicenter prevalence study in the first quarter of 2019.

Methods

We collected clinical data and rectal or fecal samples from 256 ICU patients for CPE testing. Additionally, we performed whole-genome sequencing on 40 representative CPE strains to document their molecular characteristics.

Results

Among the 256 patients, CPE was detected in 73 samples (28.5%), with prevalence varying from 3.3 to 69.0% across participating centers. We observed 13 colistin-resistant CPE strains, affecting three ICUs. Genetic analysis revealed highly diverse E. coli and K. pneumoniae strains, predominantly from international high-risk clones. Notably, blaOXA-48 and blaNDM-1 were the most prevalent carbapenemase genes. Molecular typing uncovered potential patient clusters in six centers. Significantly, longer hospital stays were associated with increased CPE carriage (p < 0.001). Nine centers across Morocco, Tunisia, Egypt, and Lebanon voluntarily participated.

Discussion

Our study provides CPE prevalence in Mediterranean ICUs and reaffirms established CPE presence in this setting but also provides updates on the molecular diversity of CPE strains. These findings highlight the imperative of reinforcing infection control measures in the participating ICUs to curtail escalated mortality rates, and of strictly applying isolation measures around patients originating from the Mediterranean region when transferred to other healthcare institutions.

Sanitation in urban areas may limit the spread of antimicrobial resistance via flies

Synanthropic filth flies are common where sanitation is poor and fecal wastes are accessible to them. These flies have been proposed as mechanical vectors for the localized transport of fecal microbes including antimicrobial resistant (AMR) organisms and associated antimicrobial resistance genes (ARGs), increasing exposure risks. We evaluated whether an onsite sanitation intervention in Maputo, Mozambique reduced the concentration of enteric bacteria and the frequency of detection of ARGs carried by flies collected in household compounds of low-income neighborhoods. Additionally, we assessed the phenotypic resistance profile of Enterobacteriaceae isolates recovered from flies during the pre-intervention phase. After fly enumeration at study compounds, quantitative polymerase chain reaction was used to quantify an enteric 16S rRNA gene (i.e., specific to a cluster of phylotypes corresponding to 5% of the human fecal microflora), 28 ARGs, and Kirby Bauer Disk Diffusion of Enterobacteriaceae isolates was utilized to assess resistance to eleven clinically relevant antibiotics. The intervention was associated with a 1.5 log10 reduction (95% confidence interval: -0.73, -2.3) in the concentration of the enteric 16S gene and a 31% reduction (adjusted prevalence ratio = 0.69, [0.52, 0.92]) in the mean number of ARGs per fly compared to a control group with poor sanitation. This protective effect was consistent across the six ARG classes that we detected. Enterobacteriaceae isolates-only from the pre-intervention phase-were resistant to a mean of 3.4 antibiotics out of the eleven assessed. Improving onsite sanitation infrastructure in low-income informal settlements may help reduce fly-mediated transmission of enteric bacteria and the ARGs carried by them.

WITHDRAWN: Evaluation of Fourier Transform Infrared spectroscopy (IR Biotyper) as a complement to Whole genome sequencing (WGS) to characterise Enterobacter cloacae , Citrobacter freundii and Klebsiella pneumoniae isolates recovered from hospital sinks

The authors have withdrawn their manuscript due to becoming aware of methodology issues related to the curation of the training set used to determine cut-off values for Biotyper cluster assignation and lack of replicate measurements on different days for the isolates analysed. It is therefore unclear whether the conclusions of the manuscript are founded and no further work is possible to correct these issues as the instrument is no longer available to the authors. If you have any questions, please contact the corresponding author.

Concurrent transmission of multiple carbapenemases in a long-term acute-care hospital

OBJECTIVE

We investigated concurrent outbreaks of Pseudomonas aeruginosa carrying blaVIM (VIM-CRPA) and Enterobacterales carrying blaKPC (KPC-CRE) at a long-term acute-care hospital (LTACH A).

METHODS

We defined an incident case as the first detection of blaKPC or blaVIM from a patient's clinical cultures or colonization screening test. We reviewed medical records and performed infection control assessments, colonization screening, environmental sampling, and molecular characterization of carbapenemase-producing organisms from clinical and environmental sources by pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing.

RESULTS

From July 2017 to December 2018, 76 incident cases were identified from 69 case patients: 51 had blaKPC, 11 had blaVIM, and 7 had blaVIM and blaKPC. Also, blaKPC were identified from 7 Enterobacterales, and all blaVIM were P. aeruginosa. We observed gaps in hand hygiene, and we recovered KPC-CRE and VIM-CRPA from drains and toilets. We identified 4 KPC alleles and 2 VIM alleles; 2 KPC alleles were located on plasmids that were identified across multiple Enterobacterales and in both clinical and environmental isolates.

CONCLUSIONS

Our response to a single patient colonized with VIM-CRPA and KPC-CRE identified concurrent CPO outbreaks at LTACH A. Epidemiologic and genomic investigations indicated that the observed diversity was due to a combination of multiple introductions of VIM-CRPA and KPC-CRE and to the transfer of carbapenemase genes across different bacteria species and strains. Improved infection control, including interventions that minimized potential spread from wastewater premise plumbing, stopped transmission.

Identification of carbapenem-resistant organism (CRO) contamination of in-room sinks in intensive care units in a new hospital bed tower

BACKGROUND

The origins and timing of inpatient room sink contamination with carbapenem-resistant organisms (CROs) are poorly understood.

METHODS

We performed a prospective observational study to describe the timing, rate, and frequency of CRO contamination of in-room handwashing sinks in 2 intensive care units (ICU) in a newly constructed hospital bed tower. Study units, A and B, were opened to patient care in succession. The patients in unit A were moved to a new unit in the same bed tower, unit B. Each unit was similarly designed with 26 rooms and in-room sinks. Microbiological samples were taken every 4 weeks from 3 locations from each study sink: the top of the bowl, the drain cover, and the p-trap. The primary outcome was sink conversion events (SCEs), defined as CRO contamination of a sink in which CRO had not previously been detected.

RESULTS

Sink samples were obtained 22 times from September 2020 to June 2022, giving 1,638 total environmental cultures. In total, 2,814 patients were admitted to study units while sink sampling occurred. We observed 35 SCEs (73%) overall; 9 sinks (41%) in unit A became contaminated with CRO by month 10, and all 26 sinks became contaminated in unit B by month 7. Overall, 299 CRO isolates were recovered; the most common species were Enterobacter cloacae and Pseudomonas aeruginosa.

CONCLUSION

CRO contamination of sinks in 2 newly constructed ICUs was rapid and cumulative. Our findings support in-room sinks as reservoirs of CRO and emphasize the need for prevention strategies to mitigate contamination of hands and surfaces from CRO-colonized sinks.

Infection prevention and control policy implementation for CPE: a cross-sectional national survey of healthcare workers reveals knowledge gaps and suboptimal practices

BACKGROUND

In 2017, Ireland pioneered a unique response to the worsening epidemiology of carbapenemase-producing Enterobacterales (CPE), declaring a national public health emergency. Subsequently, CPE mitigation guidelines and policies were implemented in acute hospitals, focused on patient screening and outbreak management, often by healthcare workers (HCWs) with limited background in infection prevention and control (IPC). CPE risks from sinks and drains remain inadequately controlled.

AIMS

To compare CPE awareness, perceptions of the role of the environment in CPE transmission, and disposal practices of liquid waste from clinical handwashing sinks between IPC HCWs and non-IPC HCWs in Ireland.

METHODS

Between December 2022 and March 2023, HCWs employed in acute hospitals in Ireland between 2017 and 2022 were invited to participate anonymously in a 30-question digital survey.

FINDINGS

Responses (N=283) were received across several clinical disciplines. In total, 21.6% of respondents were working or had previously worked in IPC roles, 84.1% of whom reported no IPC-related learning needs. In comparison with non-IPC HCWs, more IPC HCWs perceived a risk of pathogen transmission from clean water plumbing (68.9% vs 39.2%; P<0.001) and waste/drainage plumbing (81.2% vs 43.7%; P<0.001). Among nursing and medical staff, only 5.6% of IPC HCWs used clinical handwashing sinks for disposal of liquid waste, compared with 60% of non-IPC HCWs (P<0.001). In comparison with non-IPC HCWs, a greater proportion of IPC HCWs reported that they had witnessed colleagues routinely discarding liquid waste (including nutritional products, antimicrobials and patient body fluids) via clinical handwashing sinks (88.9% vs 77.9%) CONCLUSIONS: Although there is general awareness of the role of the built environment in pathogen transmission, including CPE, familiarity with sink/water-related transmission is greater among IPC HCWs. There may be opportunities to improve disposal practices for liquid waste through education targeting non-IPC HCWs.

Sink-traps are a major source for carbapenemase-producing Enterobacteriaceae transmission

OBJECTIVE

We studied the extent of carbapenemase-producing Enterobacteriaceae (CPE) sink contamination and transmission to patients in a nonoutbreak setting.

METHODS

During 2017-2019, 592 patient-room sinks were sampled in 34 departments. Patient weekly rectal swab CPE surveillance was universally performed. Repeated sink sampling was conducted in 9 departments. Isolates from patients and sinks were characterized using pulsed-field gel electrophoresis (PFGE), and pairs of high resemblance were sequenced by Oxford Nanopore and Illumina. Hybrid assembly was used to fully assemble plasmids, which are shared between paired isolates.

RESULTS

In total, 144 (24%) of 592 CPE-contaminated sinks were detected in 25 of 34 departments. Repeated sampling (n = 7,123) revealed that 52%-100% were contaminated at least once during the sampling period. Persistent contamination for >1 year by a dominant strain was common. During the study period, 318 patients acquired CPE. The most common species were Klebsiella pneumoniae, Escherichia coli, and Enterobacter spp. In 127 (40%) patients, a contaminated sink was the suspected source of CPE acquisition. For 20 cases with an identical sink-patient strain, temporal relation suggested sink-to-patient transmission. Hybrid assembly of specific sink-patient isolates revealed that shared plasmids were structurally identical, and SNP differences between shared pairs, along with signatures for potential recombination events, suggests recent sharing of the plasmids.

CONCLUSIONS

CPE-contaminated sinks are an important source of transmission to patients. Although traditionally person-to-person transmission has been considered the main route of CPE transmission, these data suggest a change in paradigm that may influence strategies of preventing CPE dissemination.

Incidence and risk factors for subsequent infections among rectal carriers with carbapenem-resistant Klebsiella pneumoniae: a systematic review and meta-analysis

BACKGROUND

Carbapenem-resistant Klebsiella pneumoniae (CRKp) is a major pathogen causing nosocomial infections with a high mortality and poor prognosis. Gastrointestinal carriage has been acknowledged as the primary reservoir of CRKp infections.

AIM

To explore the incidence and risk factors associated with CRKp infection following colonization.

METHODS

The PubMed, Web of Science, and Cochrane Library databases were searched for relevant articles published between December 1998 and June 2023. Pooled estimates with a 95% confidence interval (CI) were calculated for the incidence rate, whereas pooled odds ratios (ORs) were calculated for the risk factors for which the OR was reported in three or more studies.

FINDINGS

Fourteen studies were included in the review with 5483 patients for the assessment of incidence, whereas seven of these studies with 2170 patients were included for the analysis of risk factors. In the meta-analysis, the incidence of CRKp infections after colonization was 23.2% (17.9-28.5). Additionally, three independent risk factors for subsequent CRKp infections were identified as admission to the intensive care unit (ICU) (2.59; 95% CI: 1.64-4.11), invasive procedures (2.53; 95% CI: 1.59-4.03), and multi-site colonization (6.24; 95% CI: 2.38-16.33).

CONCLUSION

This review reveals the incidence of CRKp infections in rectal carriers in different countries, emphasizing the role of rectal colonization with CRKp as an important source of nosocomial infections. Significantly, the risk factors indicated in this review can assist clinicians in identifying CRKp carriers with an elevated risk of subsequent infections, thereby enabling further measures to be taken to prevent nosocomial infections.

Whole-genome sequencing reveals two prolonged simultaneous outbreaks involving Pseudomonas aeruginosa high-risk strains ST111 and ST235 with resistance to quaternary ammonium compounds

OBJECTIVE

Water-bearing systems are known as frequent Pseudomonas aeruginosa (PA) outbreak sources. However, many older buildings continue to have sanitary facilities in high-risk departments such as the ICU. We present two simultaneous prolonged multi-drug-resistant (MDR) PA outbreaks detected at the ICU of a pulmonology hospital, which were resolved by whole-genome sequencing (WGS).

METHODS

Outbreak management and investigations were initiated in August 2019 after detecting two patients with nosocomial VIM-2-positive MDR PA. The investigations involved weekly patient screenings for four months and extensive environmental sampling for 15 months. All patient and environmental isolates were collected and analysed by WGS.

RESULTS

From April to September 2019, we identified 10 patients with nosocomial MDR PA, including five VIM-2-positive strains. VIM-2-positive strains were also detected in nine sink drains, two toilets, and a cleaning bucket. WGS revealed that of 16 VIM-2-positive isolates, 14 were ST111 that carried qacE, or qacEΔ1 genes, whereas 13 isolates clustered (difference of ≤11 alleles by cgMLST). OXA-2 (two toilets), and OXA-2, OXA-74, PER-1 (two patients, three toilets) qacEΔ1-positive ST235 isolates dominated among VIM-2-negative isolates. The remaining seven PA strains were ST17, ST233, ST273, ST309 and ST446. Outbreak containment was achieved by replacing U-bends, and cleaning buckets, and switching from quaternary ammonium compounds (QUATs) to oxygen-releasing disinfectant products.

CONCLUSION

Comprehension and management of two simultaneous MDR PA outbreaks involving the high-risk strains ST111 and ST235 were facilitated by precise control due to identification of different outbreak sources per strain, and by the in-silico detection of high-level QUATs resistance in all isolates.

Plasmid-encoded gene duplications of extended-spectrum β-lactamases in clinical bacterial isolates

Introduction

The emergence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is an urgent and alarming One Health problem. This study aimed to investigate duplications of plasmid-encoded ESBL genes and their impact on antimicrobial resistance (AMR) phenotypes in clinical and screening isolates.

Methods

Multi-drug-resistant bacteria from hospitalized patients were collected during routine clinical surveillance from January 2022 to June 2023, and their antimicrobial susceptibility patterns were determined. Genotypes were extracted from long-read whole-genome sequencing data. Furthermore, plasmids and other mobile genetic elements associated with ESBL genes were characterized, and the ESBL genes were correlated to ceftazidime minimal inhibitory concentration (MIC).

Results

In total, we identified four cases of plasmid-encoded ESBL gene duplications that match four genetically similar plasmids during the 18-month surveillance period: five Escherichia coli and three Klebsiella pneumoniae isolates. As the ESBL genes were part of transposable elements, the surrounding sequence regions were duplicated as well. In-depth analysis revealed insertion sequence (IS)-mediated transposition mechanisms. Isolates with duplicated ESBL genes exhibited a higher MIC for ceftazidime in comparison to isolates with a single gene copy (3-256 vs. 1.5-32 mg/L, respectively).

Conclusion

ESBL gene duplications led to an increased phenotypic resistance against ceftazidime. Our data suggest that ESBL gene duplications by an IS-mediated transposition are a relevant mechanism for how AMR develops in the clinical setting and is part of the microevolution of plasmids.

The impact of an intervention to reduce dispersal from wastewater drain sites on carbapenem-resistant Pseudomonas aeruginosa colonization and bloodstream infection on a hematopoietic cell transplant and hematologic malignancy unit

OBJECTIVE

To evaluate the impact of an intervention to limit dispersal from wastewater drain (WWD) sites on meropenem-nonsusceptible Pseudomonas aeruginosa patient and environmental colonization and bloodstream infection (BSI) on a hematopoietic cell transplant (HCT) and hematologic malignancy (HM) unit.

DESIGN

This quasi-experimental study included pre/postintervention point-prevalence surveys in July 2019 and June 2020, respectively. The retrospective cohort included HCT/HM patients with P. aeruginosa BSI between 2012 and 2022.

SETTING

Adult HCT/HM unit at an academic center.

PARTICIPANTS

This study included consenting HCT/HM patients on the unit at the time of the point-prevalence surveys. HCT/HM patients with P. aeruginosa BSI between 2012 and 2022.

METHODS

A quality improvement intervention targeting WWD sites was conceived and implemented on a HCT/HM unit. Pre and postintervention colonization samples were obtained from patients and environmental sites, cultivated on selective media, then characterized by susceptibility testing. Whole-genome sequencing and phylogenetic analysis were performed on select isolates. The impact of the intervention on colonization and BSI was evaluated, as was relatedness among isolates.

RESULTS

Although colonization of WWD sites with meropenem-nonsusceptible P. aeruginosa was widespread before and after this intervention, we observed a substantial decline in patient colonization (prevalence rate ratio, 0.35; 95% confidence interval [CI], 0.04-3.12) and BSI (incidence rate ratio, 0.67; 95% CI, 0.31-1.42) after the intervention. Among 3 predominant sequence types (ST-111, ST-446, and ST-308), there was striking genetic conservation within groups and among environmental colonization, patient colonization, and BSI isolates.

CONCLUSIONS

An intervention targeting WWD sites on a HCT/HM unit had a meaningful impact on meropenem-nonsusceptible P. aeruginosa patient colonization and BSI.

[The structural and spatial design of German intensive care units from the point of view of infection control measures : Survey among ICU-KISS participants]

INTRODUCTION

Intensive care unit (ICU) structural and spatial design may play a role in infection prevention and control.

METHODS

Between 09/2021 and 11/2021 we performed an online survey among ICUs in Germany, Austria and Switzerland.

RESULTS

A total of 597 (40%) of the invited ICUs answered the survey; 20% of the ICUs were built before 1990. The median number of single rooms with interquartile range is 4 (IQR 2-6). The median total room number is 8 (IQR 6-12). The median room size is 19 (IQR 16-22) m2 for single rooms and 31 (26-37.5) m2 for multiple bed rooms. Furthermore, 80% of ICUs have sinks and 86.4% have heating, ventilation, air conditioning (HVAC) systems in patient rooms. 54.6% of ICUs must store materials outside of storage rooms due to lack of space and only 33.5% have a room dedicated to disinfection and cleaning of used medical devices. Comparing ICUs built before 1990 and after 2011 we could show a slightly increase of single rooms (3 [IQR 2-5] before 1990 vs. 5 [IQR 2-8] after 2011; p < 0.001).

DISCUSSION

A large proportion of German ICUs do not meet the requirements of German professional societies regarding the number of single rooms and size of the patient rooms. Many ICUs lack storage space and other functional rooms.

CONCLUSION

There is an urgent need to support the construction and renovation of intensive care units in Germany with adequate funding.

Cross-contamination of carbapenem-resistant Gram-negative bacteria between patients and the hospital environment in the first year of a newly built surgical ward

BACKGROUND

Transmission and outbreaks of carbapenem-resistant Gram-negative bacteria (CRGN) in hospitals are often associated with contamination of the wastewater environment. We performed a prospective observational study to investigate the colonization of the hospital wastewater environment during the first year of occupancy of the surgical intermediate and intensive care units of a newly constructed building at the University Hospital of Heidelberg, Germany.

METHODS

We performed monthly screening of the wastewater system (toilets and sinks) for 12 months, starting 1 month before opening (1st October 2020 to 30th October 2021). Admission and weekly rectal screening of patients for CRGN were also performed in parallel. Bacterial isolates were characterized by whole-genome sequencing.

RESULTS

Twenty-seven of 1978 (1.4%) admitted patients were colonized/infected with CRGN. A total of 29 CRGN isolates from 24 patients and 52 isolates were available for sequencing. Within the first month of occupancy, we identified seven patients colonized/infected with CRGN, while none were found in the environmental reservoirs. The first detection of CRGN isolates in the sewage system started five months after the first occupancy. Two previously non-colonized patients were colonized/infected with Pseudomonas aeruginosa strains colonizing the sewage system. The significant identity of plasmids carrying the carbapenemase gene suggests that long-term colonization of the sewage system facilitates the emergence of new carbapenem-resistant clones.

CONCLUSION

Cross-contamination between patients and the hospital environment is bidirectional. Our study demonstrated that contamination of the hospital wastewater environment may lead to persistent colonization and may serve as a reservoir for nosocomial acquisition of CRGN.

Multidrug-Resistant Bacteria Contaminating Plumbing Components and Sanitary Installations of Hospital Restrooms

Antimicrobial resistance (AMR) poses several issues concerning the management of hospital-acquired infections, leading to increasing morbidity and mortality rates and higher costs of care. Multidrug-resistant (MDR) bacteria can spread in the healthcare setting by different ways. The most important are direct contact transmission occurring when an individual comes into physical contact with an infected or colonized patient (which can involve healthcare workers, patients, or visitors) and indirect contact transmission occurring when a person touches contaminated objects or surfaces in the hospital environment. Furthermore, in recent years, toilets in hospital settings have been increasingly recognised as a hidden source of MDR bacteria. Different sites in restrooms, from toilets and hoppers to drains and siphons, can become contaminated with MDR bacteria that can persist there for long time periods. Therefore, shared toilets may play an important role in the transmission of nosocomial infections since they could represent a reservoir for MDR bacteria. Such pathogens can be further disseminated by bioaerosol and/or droplets potentially produced during toilet use or flushing and be transmitted by inhalation and contact with contaminated fomites. In this review, we summarize available evidence regarding the molecular features of MDR bacteria contaminating toilets of healthcare environments, with a particular focus on plumbing components and sanitary installation. The presence of bacteria with specific molecular traits in different toilet sites should be considered when adopting effective managing and containing interventions against nosocomial infections potentially due to environmental contamination. Finally, here we provide an overview of traditional and new approaches to reduce the spreading of such infections.

Activity of a foam in preventing rebound of vancomycin-resistant Enterococcus faecium-containing droplets generated from the toilet bowl

In hospital environments, droplets generated by urination within shared toilets may represent a route of dissemination for bacteria such as vancomycin-resistant Enterococcus faecium (VREfm), which contributes significantly to the burden of hospital-acquired infections. We investigated the potential activity of a foam in preventing the generation of droplets containing Enterococcus spp. during urination. A uniform layer of foam was deposited in the inner walls and at the bottom of an experimental toilet contaminated with suspensions of Enterococcus strains (including a VREfm strain). Human urination was simulated, and colonies of Enterococcus were recovered through a toilet lid where agar plates had been placed. Results showed that the foam was able to suppress production of droplets containing Enterococcus spp. generated by a liquid hitting inner toilet walls. Conversely, Enterococcus colonies were recovered in absence of foam. Moreover, the foam did not show antibacterial activity. We propose a new non-antimicrobial approach aimed at limiting transmission of multidrug-resistant bacteria, particularly in healthcare settings.

Sink interventions in the ICU to reduce risk of infection or colonization with Gram-negative pathogens: a systematic review of the literature

BACKGROUND

Healthcare-associated infections (HAIs) are a major problem in intensive care units (ICUs). The hospital water environment is a potential reservoir for Gram-negative bacteria (GNB), and it has been shown that contaminated sinks contribute to the spread of GNB in outbreak and non-outbreak settings. This study aimed to investigate which sink interventions may reduce GNB infection and colonization rates in the ICU.

METHODS

A database search (MEDLINE via PubMed, EMBASE via Ovid and ClinicalTrials.gov) was undertaken without restrictions on language or date of publication. Studies of any design were included if they described an intervention on the water fixtures in patient rooms, and presented data about HAI or colonization rates in non-outbreak settings. Acquisition (infection and/or colonization) rates of GNB and Pseudomonas aeruginosa were analysed as outcomes.

RESULTS

In total, 4404 records were identified. Eleven articles were included in the final analysis. No randomized controlled trials were included in the analysis, and all studies were reported to have moderate to serious risk of bias. Removing sinks and applying filters on taps had a significant impact on GNB acquisition, but there was high heterogeneity among reported outcomes and sample size among the studies.

CONCLUSION

Few studies have investigated the association of sinks in patient rooms with healthcare-associated acquisition of GNB in non-outbreak settings. Heterogeneity in study design made it impossible to generalize the results. Prospective trials are needed to further investigate whether removing sinks from patient rooms can reduce the endemic rate of HAIs in the ICU.

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

BACKGROUND

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).

AIM

To investigate this ICU long-term CPO outbreak involving multiple species and a persistent environmental reservoir.

METHODS

Active case finding, environmental sampling, whole-genome sequencing (WGS) analysis of patient and environmental strains, and implemented control strategies were described in this study.

FINDINGS

From 2018 to 2022, 37 patients became colonized 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 strain 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 pump 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 recolonization of the proximal sink drain by CPO.

CONCLUSION

The persistence in the hospital environment of antibiotic- and disinfectant-resistant bacteria with the ability to transfer mobile genetic elements poses a serious threat to ICU patients with a risk of shifting towards an endemicity scenario. Innovative strategies are needed to address persistent environmental reservoirs and prevent CPO transmission.

Genomic epidemiology of carbapenemase-producing Gram-negative bacteria at the human-animal-environment interface in Djibouti city, Djibouti

The emergence of carbapenem resistance is a major public health threat in sub-Saharan Africa but remains poorly understood, particularly at the human-animal-environment interface. This study provides the first One Health-based study on the epidemiology of Carbapenemase-Producing Gram-Negative Bacteria (CP-GNB) in Djibouti City, Djibouti, East Africa. In total, 800 community urine samples and 500 hospital specimens from humans, 270 livestock fecal samples, 60 fish samples, and 20 water samples were collected and tested for carbapenem resistance. The overall estimated CP-GNB prevalence was 1.9 % (32/1650 samples) and specifically concerned 0.3 % of community urine samples, 2.8 % of clinical specimens, 2.6 % of livestock fecal samples, 11.7 % of fish samples, and 10 % of water samples. The 32 CP-GNB included 19 Escherichia coli, seven Acinetobacter baumannii, five Klebsiella pneumoniae, and one Proteus mirabilis isolate. Short-read (Illumina) and long-read (Nanopore) genome sequencing revealed that carbapenem resistance was mainly associated with chromosomal carriage of blaNDM-1, blaOXA-23, blaOXA-48, blaOXA-66, and blaOXA-69 in A. baumannii, and with plasmid carriage in Enterobacterales (blaNDM-1 and blaOXA-181 in E. coli, blaNDM-1, blaNDM-5 and blaOXA-48 in K. pneumoniae, and blaNDM-1 in P. mirabilis). Moreover, 17/32 CP-GNB isolates belonged to three epidemic clones: (1) A. baumannii sequence type (ST) 1697,2535 that showed a distribution pattern consistent with intra- and inter-hospital dissemination; (2) E. coli ST10 that circulated at the human-animal-environment interface; and (3) K. pneumoniae ST147 that circulated at the human-environment interface. Horizontal exchanges probably contributed to carbapenem resistance dissemination in the city, especially the blaOXA-181-carrying ColKP3-IncX3 hybrid plasmid that was found in E. coli isolates belonging to different STs. Our study highlights that despite a relatively low CP-GNB prevalence in Djibouti City, plasmids harboring carbapenem resistance circulate in humans, animals and environment. Our findings stress the need to implement preventive and control measures for reducing the circulation of this potentially emerging public health threat.

Unveiling the hidden threat of carbapenemase-producing Enterobacteriaceae in hospital water environments: A single-center study

This retrospective study examined the presence of carbapenemase-producing Enterobacteriaceae in hospital water environments. Results showed that carbapenemase-producing Enterobacteriaceae was detected in 41.5% of the samples within 1 m of a water source (showers or sinks), with 20.6% of the positive samples associated with shower water sources.

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.

Molecular characterization of a suspected IMP-type carbapenemase-producing Pseudomonas aeruginosa outbreak reveals two simultaneous outbreaks in a tertiary-care hospital

OBJECTIVE

To describe IMP-type carbapenemase-producing Pseudomonas aeruginosa outbreaks at Galdakao University Hospital between March 2021 to December 2021.

DESIGN

Outbreak report.

SETTING

Galdakao University Hospital is a tertiary-care hospital in the Basque Country (northern Spain).

PATIENTS

All patients with a positive IMP-type carbapenemase producing Pseudomonas aeruginosa (IMP-PA) culture were included in this study, both colonization and infection cases.

METHODS

An outbreak investigation was conducted, in which molecular epidemiology analysis [pulsed-field gel electrophoresis and whole-genome sequencing (WGS)] and environmental screenings were performed.

RESULTS

Between March and December 2021, 21 cases of IMP-PA were detected in Galdakao University Hospital: 18 infection cases and 3 colonization cases. In total, 4 different pulsotypes were detected belonging to 4 clones according to WGS: ST175 (n = 14), ST633 (n = 3), ST179 (n = 3), and ST348 (n = 1). IMP-13 was detected in most isolates belonging to the ST175 clone and in all ST179 and ST348 clones, whereas IMP-29 was detected in isolates belonging to the ST633 clone. Clinical isolates belonging to the ST175 clone were isolated mainly from patients admitted to the respiratory ward, and isolates belonging to the ST633 clone from patients admitted to the ICU. Two environmental isolates belonging to the ST175 clone were detected in the respiratory ward.

CONCLUSIONS

Molecular and genomic epidemiology revealed that there had been 2 independent IMP-PA outbreaks, one of long duration in the respiratory ward and the other more limited in the ICU.

The contribution of human conflict to the development of antimicrobial resistance

Pallet et al. discuss the impact of human conflict on development of antimicrobial resistance. They overview approaches to limit the spread of antimicrobial resistance, using the ongoing conflict in Ukraine as an example of the challenges and opportunities.

Investigation of a Salmonella Montevideo Outbreak Related to the Environmental Contamination of a Restaurant Kitchen Drainage System, Québec, Canada, 2020-2021

In May 2020, the Direction de santé publique du CIUSSS de la Capitale-Nationale (DSPu) received a report from the Laboratoire de santé publique du Québec of a cluster of three cases of Salmonella enterica enterica, serogroup C1, serotype Montevideo. The epidemiological investigation identified a total of 67 cases between January 1, 2020, and August 13, 2021, 66% of which were directly linked to a restaurant in the area. The Salmonella strains from most of these cases were found to be identical by whole-genome sequencing (cluster code 2005MontWGS-1QC). The initial inspection of the restaurant by the competent authorities (Ministère de l'agriculture, des pêcheries et de l'alimentation du Québec) - including the evaluation of hygiene and food safety, the search for cases of illness among workers and food sampling - was unable to establish the source of the outbreak. Environmental samples showed that the restaurant's kitchen drains were contaminated with the same strain of Salmonella Montevideo as the cases in the outbreak. Several cleaning and disinfection methods were used repeatedly. When environmental sampling at the restaurant sites was repeatedly and consecutively negative, cases in the community stopped. The prior occurrence of a fire in the kitchen may have played a role in the contamination of the restaurant drains. In conclusion, public health professionals should consider drainage systems (plumbing) and possible aerosolization of bacteria as a potential source of a restaurant-related salmonellosis outbreak.

Detection and Characterization of Carbapenemase-Producing Escherichia coli and Klebsiella pneumoniae from Hospital Effluents of Ouagadougou, Burkina Faso

Hospital wastewater is a recognized reservoir for resistant Gram-negative bacteria. This study aimed to screen for carbapenemase-producing Escherichia coli and Klebsiella pneumoniae and their resistance determinants in two hospital effluents of Ouagadougou. Carbapenem-resistant E. coli and K. pneumoniae were selectively isolated from wastewater collected from two public hospitals in Ouagadougou, Burkina Faso. Bacterial species were identified via MALDI-TOF mass spectrometry. Carbapenemase production was studied phenotypically using antibiotic susceptibility testing via the disk diffusion method. The presence of carbapenemases was further characterized by PCR. A total of 14 E. coli (13.59%) and 19 K. pneumoniae (17.92%) carbapenemase-producing isolates were identified with different distributions. They were, respectively, blaNDM (71.43%), blaVIM (42.86%), blaIMP (28.57%), blaKPC (14.29%), blaOXA-48 (14.29%); and blaKPC (68.42%), blaNDM (68.42%), blaIMP (10.53%), blaVIM (10.53%), and blaOXA-48 (5.26%). In addition, eight (57.14%) E. coli and eleven (57.89%) K. pneumoniae isolates exhibited more than one carbapenemase, KPC and NDM being the most prevalent combination. Our results highlight the presence of clinically relevant carbapenemase-producing isolates in hospital effluents, suggesting their presence also in hospitals. Their spread into the environment via hospital effluents calls for intensive antimicrobial resistance (AMR) surveillance.

Nutritional drinks and enteral feeds promote the growth of carbapenemase-producing Enterobacterales in conditions that simulate disposal in hospital sinks

BACKGROUND

Studies have shown that nutritional products are discarded via handwash sinks by healthcare workers, and this practice may promote bacterial growth, including growth of pathogens such as carbapenemase-producing Enterobacterales (CPE). Outbreaks and acquisition of CPE in nosocomial settings are associated with negative outcomes for patients and hospitals.

OBJECTIVES

To investigate the potential growth-promoting effect of nutritional support drinks (NSDs) and enteral tube-feed products (ETFPs) on CPE.

METHODS

Six different CPE strains were grown in five different diluted NSDs, five different diluted ETFPs, Mueller-Hinton broth (MHB) and M9 minimal salts media to simulate discarding a small volume of nutritional product in a u-bend, already containing liquid. CPE were enumerated at 0 h, 6 h and 24 h, and compared using two-way analysis of variance and Dunett test, with confidence levels at 95%. Spearman's r was used to measure the strength of correlation between component concentrations in nutritional products and CPE growth.

RESULTS

All NSDs and ETFPs promoted CPE growth that exceeded both M9 (negative growth control) and MHB (positive growth control). In several cases, growth in NSDs/ETFPs was significantly greater compared with growth in MHB.

CONCLUSION

Nutritional products support CPE growth under in-vitro conditions. The propensity of CPE to survive in drain pipework suggests that inappropriate product disposal may further nourish established CPE in these environmental reservoirs. The growth observed in diluted NSDs and ETFPs shows that modifiable practices should be optimized to mitigate the potential risk of CPE transmission from these reservoirs.

Sinks in patient rooms in ICUs are associated with higher rates of hospital-acquired infection: a retrospective analysis of 552 ICUs

BACKGROUND

Sinks in hospitals are a possible reservoir for healthcare-related pathogens. They have been identified as a source of nosocomial outbreaks in intensive care units (ICU); however, their role in non-outbreak settings remains unclear.

AIM

To investigate whether sinks in ICU patient rooms are associated with a higher incidence of hospital-acquired infection (HAI).

METHODS

This analysis used surveillance data from the ICU component of the German nosocomial infection surveillance system (KISS) from 2017 to 2020. Between September and October 2021, all participating ICUs were surveyed about the presence of sinks in their patient rooms. The ICUs were then divided into two groups: the no-sink group (NSG) and the sink group (SG). Primary and secondary outcomes were total HAIs and HAIs associated with Pseudomonas aeruginosa (HAI-PA).

FINDINGS

In total, 552 ICUs (NSG N=80, SG N=472) provided data about sinks, total HAIs and HAI-PA. The incidence density per 1000 patient-days of total HAIs was higher in ICUs in the SG (3.97 vs 3.2). The incidence density of HAI-PA was also higher in the SG (0.43 vs 0.34). The risk of HAIs associated with all pathogens [incidence rate ratio (IRR)=1.24, 95% confidence interval (CI) 1.03-1.50] and the risk of lower respiratory tract infections associated with P. aeruginosa (IRR=1.44, 95% CI 1.10-1.90) were higher in ICUs with sinks in patient rooms. After adjusting for confounders, sinks were found to be an independent risk factor for HAI (adjusted IRR 1.21, 95% CI 1.01-1.45).

CONCLUSIONS

Sinks in patient rooms are associated with a higher number of HAIs per patient-day in the ICU. This should be considered when planning new ICUs or renovating existing ones.

Intensive care unit sinks are persistently colonized with multidrug resistant bacteria and mobilizable, resistance-conferring plasmids

Contamination of hospital sinks with microbial pathogens presents a serious potential threat to patients, but our understanding of sink colonization dynamics is largely based on infection outbreaks. Here, we investigate the colonization patterns of multidrug-resistant organisms (MDROs) in intensive care unit sinks and water from two hospitals in the USA and Pakistan collected over 27 months of prospective sampling. Using culture-based methods, we recovered 822 bacterial isolates representing 104 unique species and genomospecies. Genomic analyses revealed long-term colonization by Pseudomonas spp. and Serratia marcescens strains across multiple rooms. Nanopore sequencing uncovered examples of long-term persistence of resistance-conferring plasmids in unrelated hosts. These data indicate that antibiotic resistance (AR) in Pseudomonas spp. is maintained both by strain colonization and horizontal gene transfer (HGT), while HGT maintains AR within Acinetobacter spp. and Enterobacterales, independent of colonization. These results emphasize the importance of proactive, genomic-focused surveillance of built environments to mitigate MDRO spread. IMPORTANCE Hospital sinks are frequently linked to outbreaks of antibiotic-resistant bacteria. Here, we used whole-genome sequencing to track the long-term colonization patterns in intensive care unit (ICU) sinks and water from two hospitals in the USA and Pakistan collected over 27 months of prospective sampling. We analyzed 822 bacterial genomes, representing over 100 different species. We identified long-term contamination by opportunistic pathogens, as well as transient appearance of other common pathogens. We found that bacteria recovered from the ICU had more antibiotic resistance genes (ARGs) in their genomes compared to matched community spaces. We also found that many of these ARGs are harbored on mobilizable plasmids, which were found shared in the genomes of unrelated bacteria. Overall, this study provides an in-depth view of contamination patterns for common nosocomial pathogens and identifies specific targets for surveillance.

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

BACKGROUND

Accumulating 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.

METHODS

Environmental 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.

RESULTS

The 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.

CONCLUSIONS

Our 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.

Environmental Contamination and Persistence of Clostridioides difficile in Hospital Wastewater Systems

Clostridioides difficile produces an environmentally resistant dormant spore morphotype that infected patients shed to the hospital environment. C. difficile spores persist in clinical reservoirs that are not targeted by hospital routine cleaning protocols. Transmissions and infections from these reservoirs present a hazard to patient safety. This study aimed to assess the impact of patients acutely suffering from C. difficile-associated diarrhea (CDAD) on C. difficile environmental contamination to identify potential reservoirs. Twenty-three hospital rooms accommodating CDAD inpatients with corresponding soiled workrooms of 14 different wards were studied in a German maximum-care hospital. Additionally, four rooms that never accommodated CDAD patients were examined as negative controls. Stagnant water and biofilms from sinks, toilets, and washer disinfector (WD) traps as well as swabs from cleaned bedpans and high-touch surfaces (HTSs) were sampled. For detection, a culture method was used with selective medium. A latex agglutination assay and a Tox A/B enzyme-linked immunosorbent assay were performed with suspect colonies. Stagnant water and biofilms in hospital traps (29%), WDs (34%), and HTSs (37%) were found to be reservoirs for large amounts of C. difficile during the stay of CDAD inpatients that decreased but could persist 13 ± 6 days after their discharge (13%, 14%, and 9.5%, respectively). Control rooms showed none or only slight contamination restricted to WDs. A short-term cleaning strategy was implemented that reduced C. difficile in stagnant water almost entirely. IMPORTANCE Wastewater pipes are microbial ecosystems. The potential risk of infection emanating from the wastewater for individuals is often neglected, since it is perceived to remain in the pipes. However, sewage systems start with siphons and are thus naturally connected to the outside world. Wastewater pathogens do not only flow unidirectionally to wastewater treatment plants but also retrogradely, e.g., through splashing water from siphons to the hospital environment. This study focused on the pathogen C. difficile, which can cause severe and sometimes fatal diarrheas. This study shows how patients suffering from such diarrheas contaminate the hospital environment with C. difficile and that contamination persists in siphon habitats after patient discharge. This might pose a health risk for hospitalized patients afterward. Since this pathogen's spore morphotype is very environmentally resistant and difficult to disinfect, we show a cleaning measure that can almost entirely eliminate C. difficile from siphons.

The role of plasmids in carbapenem resistant E. coli in Alameda County, California

BACKGROUND

Antimicrobial resistant infections continue to be a leading global public health crisis. Mobile genetic elements, such as plasmids, have been shown to play a major role in the dissemination of antimicrobial resistance (AMR) genes. Despite its ongoing threat to human health, surveillance of AMR in the United States is often limited to phenotypic resistance. Genomic analyses are important to better understand the underlying resistance mechanisms, assess risk, and implement appropriate prevention strategies. This study aimed to investigate the extent of plasmid mediated antimicrobial resistance that can be inferred from short read sequences of carbapenem resistant E. coli (CR-Ec) in Alameda County, California. E. coli isolates from healthcare locations in Alameda County were sequenced using an Illumina MiSeq and assembled with Unicycler. Genomes were categorized according to predefined multilocus sequence typing (MLST) and core genome multilocus sequence typing (cgMLST) schemes. Resistance genes were identified and corresponding contigs were predicted to be plasmid-borne or chromosome-borne using two bioinformatic tools (MOB-suite and mlplasmids).

RESULTS

Among 82 of CR-Ec identified between 2017 and 2019, twenty-five sequence types (STs) were detected. ST131 was the most prominent (n = 17) followed closely by ST405 (n = 12). bla_CTX-M were the most common ESBL genes and just over half (18/30) of these genes were predicted to be plasmid-borne by both MOB-suite and mlplasmids. Three genetically related groups of E. coli isolates were identified with cgMLST. One of the groups contained an isolate with a chromosome-borne bla_CTX-M-15 gene and an isolate with a plasmid-borne bla_CTX-M-15 gene.

CONCLUSIONS

This study provides insights into the dominant clonal groups driving carbapenem resistant E. coli infections in Alameda County, CA, USA clinical sites and highlights the relevance of whole-genome sequencing in routine local genomic surveillance. The finding of multi-drug resistant plasmids harboring high-risk resistance genes is of concern as it indicates a risk of dissemination to previously susceptible clonal groups, potentially complicating clinical and public health intervention.

Characterisation of pellicle-forming ability in clinical carbapenem-resistant Acinetobacter baumannii

Background

Acinetobacter baumannii was reported to have resistance towards carbapenems and the ability to form an air-liquid biofilm (pellicle) which contributes to their virulence. The GacSA two-component system has been previously shown to play a role in pellicle formation. Therefore, this study aims to detect the presence of gacA and gacS genes in carbapenem-resistant Acinetobacter baumannii (CRAB) isolates recovered from patients in intensive care units and to investigate their pellicle forming ability.

Methods

The gacS and gacA genes were screened in 96 clinical CRAB isolates using PCR assay. Pellicle formation assay was performed in Mueller Hinton medium and Luria Bertani medium using borosilicate glass tubes and polypropylene plastic tubes. The biomass of the pellicle was quantitated using the crystal violet staining assay. The selected isolates were further assessed for their motility using semi-solid agar and monitored in real-time using real-time cell analyser (RTCA).

Results

All 96 clinical CRAB isolates carried the gacS and gacA genes, however, only four isolates (AB21, AB34, AB69 and AB97) displayed the ability of pellicle-formation phenotypically. These four pellicle-forming isolates produced robust pellicles in Mueller Hinton medium with better performance in borosilicate glass tubes in which biomass with OD₅₇₀ ranging from 1.984 ± 0.383 to 2.272 ± 0.376 was recorded. The decrease in cell index starting from 13 hours obtained from the impedance-based RTCA showed that pellicle-forming isolates had entered the growth stage of pellicle development.

Conclusion

These four pellicle-forming clinical CRAB isolates could be potentially more virulent, therefore further investigation is warranted to provide insights into their pathogenic mechanisms.

Predominance of Multidrug-Resistant Gram-Negative Bacteria on Contaminated Surfaces at a Tertiary Hospital in Tanzania: A Call to Strengthening Environmental Infection Prevention and Control Measures

The spreading of multidrug resistance (MDR) strains in the hospital settings via contaminated surfaces have been increasingly reported where Gram-negative bacteria have been implicated in causing most nosocomial infections. This study aimed to determine the rate of contamination with multi-resistant gram-negative bacteria in the hospital environment. A cross-sectional study was conducted at Muhimbili National Hospital paediatric department, between July and August 2020. Non-repetitive surface swab samples were collected from predefined surfaces and medical device surfaces, and cultured on MacConkey agar with and without antibiotics. Isolates were identified using biochemical test and tested for antibiotic susceptibility using the Kirby-Bauer disk diffusion method. The rate of hospital contamination with Gram-negative bacteria across the Pediatrics units was 30%, with a high rate observed in oncology units (34.8%) and the malnutrition/diarrhoea ward (32.1%). Sink/washing basin had the highest frequency of bacterial contamination (74.2%). We observed a high rate of ESBL (32.5%), with Acinetobacter baumannii, Klebsiella pneumoniae, and E. coli being the predominant ESBL-producing Gram-negative bacteria, while carbapenemase-producing Gram-negative bacteria was detected at 22.8%. Highest resistance rates (63-100%) were observed against ceftriaxone and trimethoprim-sulfamethoxazole. Up to 51% of the Gram-negative bacteria showed resistant to meropenem. MDR strains were detected in 61.4% of Gram-negative bacteria isolated. In conclusion, we observed a high rate of MDR bacteria contaminating hospital surfaces. The higher rate of MDR calls for a need to strengthen infectious prevention control measures, including cleaning practices in the hospital environment, to reduce the risk of transmission of resistant strains to patients and healthcare workers.

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.

Emergence of Small Colony Variants Is an Adaptive Strategy Used by Pseudomonas aeruginosa to Mitigate the Effects of Redox Imbalance

The ability to generate a subpopulation of small colony variants (SCVs) is a conserved feature of Pseudomonas aeruginosa and could represent a key adaptive strategy to colonize and persist in multiple niches. However, very little is known about the role of the SCV phenotype, the conditions that promote its emergence, and its possible involvement in an adaptive strategy. In the present work, we investigated the in vitro selective conditions promoting the emergence of SCVs from the prototypical strain PA14, which readily forms SCVs in nonagitated standing cultures. We found that O₂ limitation, which causes a redox imbalance, is the main factor selecting for the SCV phenotype, which promotes survival of the population via formation of a biofilm at the air-liquid interface to access the electron acceptor. When this selective pressure is relieved by aeration or supplementation of an alternative electron acceptor, SCVs are barely detectable. We also observed that SCV emergence contributes to redox rebalancing, suggesting that it is involved in an adaptive strategy. We conclude that selection for the SCV phenotype is an adaptive solution adopted by P. aeruginosa to access poorly available O₂. IMPORTANCE The bacterium Pseudomonas aeruginosa is an opportunistic pathogen that thrives in many environments. It poses a significant health concern, notably because it is a causative agent of nosocomial infections and the most prevalent pathogen found in the lungs of people with cystic fibrosis. In infected hosts, its persistence is often related to the emergence of an alternative phenotype known as small colony variant (SCV). Identification of conditions selecting for the SCV phenotype contributes to knowledge regarding adaptive mechanisms exploited by P. aeruginosa to survive in multiple niches and persist during infections. Hindering this adaptation strategy could help control persistent P. aeruginosa infections.

Genome-based typing reveals rare events of patient contamination with Pseudomonas aeruginosa from other patients and sink traps in a medical intensive care unit

AIM

We used genome-based typing data with the aim of identifying the routes of acquisition of Pseudomonas aeruginosa by patients hospitalized in a medical intensive care unit (MICU) over a long period in a non-epidemic context.

METHODS

This monocentric prospective study took place over 10 months in 2019 in a 15-bed MICU that applies standard precautions of hygiene. Lockable sink traps installed at all water points of use were bleach disinfected twice a week. We sampled all sink traps weekly to collect 404 P. aeruginosa environmental isolates and collected all P. aeruginosa isolates (N = 115) colonizing or infecting patients (N = 65). All isolates had their phenotypic resistance profile determined and their genome sequenced, from which we identified resistance determinants and assessed the population structure of the collection at the nucleotide level to identify events of P. aeruginosa transmission.

FINDINGS

All sink traps were positive for P. aeruginosa, each sink trap being colonized for several months by one or more clones. The combination of genomic and spatiotemporal data identified one potential event of P. aeruginosa transmission from a sink trap to a patient (1/65, 1.5%) and six events of patient cross-transmission, leading to the contamination of five patients (5/65, 7.7%). All transmitted isolates were fully susceptible to β-lactams and aminoglycosides.

CONCLUSIONS

Genome-based typing revealed the contamination of patients by P. aeruginosa originating from sink traps to be infrequent (1.5%) in an MICU with sink trap-bleaching measures, and that only 7.7% of the patients acquired P. aeruginosa originating from another patient.

A protracted outbreak of difficult-to-treat resistant Pseudomonas aeruginosa in a haematology unit: a matched case-control study demonstrating increased risk with use of fluoroquinolone

BACKGROUND

Between September 2016 and November 2020, 17 cases of difficult-to-treat resistant Pseudomonas aeruginosa (DTR-PA) were reported in haematology patients at a tertiary referral hospital in the North of England.

AIM

A retrospective case-control study was conducted to investigate the association between DTR-PA infection and clinical interventions, patient movement, antimicrobial use and comorbidities.

METHODS

Cases were patients colonized or infected with the outbreak strain of DTR-PA who had been admitted to hospital prior to their positive specimen. Exposures were extracted from medical records, and cases were compared with controls using conditional logistic regression. Environmental and microbiological investigations were also conducted.

FINDINGS

Seventeen cases and 51 controls were included. The final model included age [>65 years, adjusted OR (aOR) 6.85, P=0.232], sex (aOR 0.60, P=0.688), admission under the transplant team (aOR 14.27, P=0.43) and use of ciprofloxacin (aOR 102.13, P=0.030). Investigations did not indicate case-to-case transmission or a point source, although a common environmental source was highly likely.

CONCLUSION

This study found that the use of fluoroquinolones is an independent risk factor for DTR-PA in haematology patients. Antimicrobial stewardship and review of fluoroquinolone prophylaxis should be considered as part of PA outbreak investigations in addition to standard infection control interventions.