Nosocomial Infections with IMP-19-Producing Pseudomonas aeruginosa Linked to Contaminated Sinks, France

Bactericidal effectors of the Stenotrophomonas maltophilia type IV secretion system: functional definition of the nuclease TfdA and structural determination of TfcB

Stenotrophomonas maltophilia expresses a type IV protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria and does so partly by secreting the effector TfcB. Here, we report the structure of TfcB, comprising an N-terminal domain similar to the catalytic domain of glycosyl hydrolase (GH-19) chitinases and a C-terminal domain for recognition and translocation by the T4SS. Utilizing a two-hybrid assay to measure effector interactions with the T4SS coupling protein VirD4, we documented the existence of five more T4SS substrates. One of these was protein 20845, an annotated nuclease. A S. maltophilia mutant lacking the gene for 20845 was impaired for killing Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Moreover, the cloned 20845 gene conferred robust toxicity, with the recombinant E. coli being rescued when 20845 was co-expressed with its cognate immunity protein. The 20845 effector was an 899 amino-acid protein, comprised of a GHH-nuclease domain in its N-terminus, a large central region of indeterminant function, and a C-terminus for secretion. Engineered variants of the 20845 gene that had mutations in the predicted catalytic site did not impede E. coli, indicating that the antibacterial effect of 20845 involves its nuclease activity. Using flow cytometry with DNA staining, we determined that 20845, but not its mutant variants, confers a loss in DNA content of target bacteria. Database searches revealed that uncharacterized homologs of 20845 occur within a range of bacteria. These data indicate that the S. maltophilia T4SS promotes interbacterial competition through the action of multiple toxic effectors, including a potent, novel DNase.IMPORTANCEStenotrophomonas maltophilia is a multi-drug-resistant, Gram-negative bacterium that is an emerging pathogen of humans. Patients with cystic fibrosis are particularly susceptible to S. maltophilia infection. In hospital water systems and various types of infections, S. maltophilia co-exists with other bacteria, including other pathogens such as Pseudomonas aeruginosa. We previously demonstrated that S. maltophilia has a functional VirB/D4 type VI protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria. Since most work on antibacterial systems involves the type VI secretion system, this observation remains noteworthy. Moreover, S. maltophilia currently stands alone as a model for a human pathogen expressing an antibacterial T4SS. Using biochemical, genetic, and cell biological approaches, we now report both the discovery of a novel antibacterial nuclease (TfdA) and the first structural determination of a bactericidal T4SS effector (TfcB).

Large-scale characterization of hospital wastewater system microbiomes and clinical isolates from infected patients: profiling of multi-drug-resistant microbial species

BACKGROUND

Hospital-acquired infections (HAIs) and infectious agents exhibiting antimicrobial resistance (AMR) are challenges globally. Environmental patient-facing wastewater apparatus including handwashing sinks, showers and toilets are increasingly identified as sources of infectious agents and AMR genes.

AIM

To provide large-scale metagenomics analysis of wastewater systems in a large teaching hospital in the Republic of Ireland experiencing multi-drug-resistant HAI outbreaks.

METHODS

Wastewater pipe sections (N=20) were removed immediately prior to refurbishment of a medical ward where HAIs had been endemic. These comprised toilet U-bends, and sink and shower drains. Following DNA extraction, each pipe section underwent metagenomic analysis.

FINDINGS

Diverse taxonomic and resistome profiles were observed, with members of phyla Proteobacteria and Actinobacteria dominating (38.23 ± 5.68% and 15.78 ± 3.53%, respectively). Genomes of five clinical isolates were analysed. These AMR bacterial isolates were from patients >48 h post-admission to the ward. Genomic analysis determined that the isolates bore a high number of antimicrobial resistance genes (ARGs).

CONCLUSION

Comparison of resistome profiles of isolates and wastewater metagenomes revealed high degrees of similarity, with many identical ARGs shared, suggesting probable acquisition post-admission. The highest numbers of ARGs observed were those encoding resistance to clinically significant and commonly used antibiotic classes. Average nucleotide identity analysis confirmed the presence of highly similar or identical genomes in clinical isolates and wastewater pipes. These unique large-scale analyses reinforce the need for regular cleaning and decontamination of patient-facing hospital wastewater pipes and effective infection control policies to prevent transmission of nosocomial infection and emergence of AMR within potential wastewater reservoirs.

Prioritization of Critical Factors for Surveillance of the Dissemination of Antibiotic Resistance in Pseudomonas aeruginosa: A Systematic Review

Pseudomonas aeruginosa is the primary opportunistic human pathogen responsible for a range of acute and chronic infections; it poses a significant threat to immunocompromised patients and is the leading cause of morbidity and mortality for nosocomial infections. Its high resistance to a diverse array of antimicrobial agents presents an urgent health concern. Among the mechanisms contributing to resistance in P. aeruginosa, the horizontal acquisition of antibiotic resistance genes (ARGs) via mobile genetic elements (MGEs) has gained recognition as a substantial concern in clinical settings, thus indicating that a comprehensive understanding of ARG dissemination within the species is strongly required for surveillance. Here, two approaches, including a systematic literature analysis and a genome database survey, were employed to gain insights into ARG dissemination. The genome database enabled scrutinizing of all the available sequence information and various attributes of P. aeruginosa isolates, thus providing an extensive understanding of ARG dissemination within the species. By integrating both approaches, with a primary focus on the genome database survey, mobile ARGs that were linked or correlated with MGEs, important sequence types (STs) carrying diverse ARGs, and MGEs responsible for ARG dissemination were identified as critical factors requiring strict surveillance. Although human isolates play a primary role in dissemination, the importance of animal and environmental isolates has also been suggested. In this study, 25 critical mobile ARGs, 45 critical STs, and associated MGEs involved in ARG dissemination within the species, are suggested as critical factors. Surveillance and management of these prioritized factors across the One Health sectors are essential to mitigate the emergence of multidrug-resistant (MDR) and extensively resistant (XDR) P. aeruginosa in clinical settings.

Waterborne infections in haemato-oncology units - a narrative review

Bone marrow transplant and haemato-oncology patients are at risk of healthcare associated infections due to waterborne pathogens. We undertook a narrative review of waterborne outbreaks in haemato-oncology patients from 2000-2022. Databases searched included Pubmed, DARE and CDSR and were undertaken by two authors. We analysed the organisms implicated, sources identified and infection prevention and control strategies implemented. The most commonly implicated pathogens were Pseudomonas aeruginosa, non-tuberculous mycobacteria and Legionella pneumophila. Bloodstream infection was the most common clinical presentation. The majority of incidents employed multimodal strategies to achieve control, addressing both the water source and routes of transmission. This review highlights the risk to haemato-oncology patients from waterborne pathogens and discusses future preventative strategies and the requirement for new UK guidance for haemato-oncology units.

Containment of a Verona Integron-Encoded Metallo-Beta-Lactamase-Producing Pseudomonas aeruginosa Outbreak Associated With an Acute Care Hospital Sink-Tennessee, 2018-2020

Background

Contaminated healthcare facility wastewater plumbing is recognized as a source of carbapenemase-producing organism transmission. In August 2019, the Tennessee Department of Health (TDH) identified a patient colonized with Verona integron-encoded metallo-beta-lactamase-producing carbapenem-resistant Pseudomonas aeruginosa (VIM-CRPA). A record review revealed that 33% (4 of 12) of all reported patients in Tennessee with VIM had history of prior admission to acute care hospital (ACH) A intensive care unit (ICU) Room X, prompting further investigation.

Methods

A case was defined as polymerase chain reaction detection of bla_VIM in a patient with prior admission to ACH A from November 2017 to November 2020. The TDH performed point prevalence surveys, discharge screening, onsite observations, and environmental testing at ACH A. The VIM-CRPA isolates underwent whole-genome sequencing (WGS).

Results

In a screening of 44% (n = 11) of 25 patients admitted to Room X between January and June 2020, we identified 36% (n = 4) colonized with VIM-CRPA, resulting in 8 cases associated with Room X from March 2018 to June 2020. No additional cases were identified in 2 point-prevalence surveys of the ACH A ICU. Samples from the bathroom and handwashing sink drains in Room X grew VIM-CRPA; all available case and environmental isolates were found to be ST253 harboring bla_VIM-1 and to be closely related by WGS. Transmission ended after implementation of intensive water management and infection control interventions.

Conclusions

A single ICU room's contaminated drains were associated with 8 VIM-CRPA cases over a 2-year period. This outbreak highlights the need to include wastewater plumbing in hospital water management plans to mitigate the risk of transmission of antibiotic-resistant organisms to patients.

Splash generation and droplet dispersal in a well-designed, centralized high-level disinfection unit

BACKGROUND

Sterile processing personnel routinely decontaminate medical devices that are heavily soiled with blood, tissue, and secretions. Contamination may spread throughout processing areas, potentially exposing personnel and patient-ready devices, especially when there is insufficient separation between the dirty and clean areas.

OBJECTIVE

This study aimed to identify activities that generate splash, determine how far droplets travel during manual cleaning, characterize the impact of practices on splash generation, and assess effectiveness of personal protective equipment (PPE) at preventing splash exposure to technicians and visitors in the decontamination unit.

METHODS

Moisture-detection paper was affixed to PPE and environmental surfaces in a new processing department designed to optimize workflow and prevent cross-contamination. Droplet generation and dispersal were assessed during manual cleaning of a colonoscope and a transvaginal ultrasound probe.

RESULTS

Splash was generated by most activities and droplets were detected up to 7.25 feet away. Transporting wet endoscopes dispersed droplets on a 15-foot path from the sink to the automated endoscope reprocessor. Extensive droplets were detected on PPE worn by technicians at the sink and observers 3-4 feet away.

CONCLUSIONS

Manual cleaning of devices generated substantial splash, drenching technicians and the environment with droplets that traveled more than 7 feet. Engineering controls and better PPE are needed to reduce personnel exposure and risks associated with the potential dispersal of contaminated fluids throughout the facility.

Droplet dispersal in decontamination areas of instrument reprocessing suites

BACKGROUND

Personnel working in sterile processing or endoscope reprocessing departments are at high risk of exposure to tissue, blood, and patient fluids when decontaminating reusable medical instruments and equipment. The effectiveness of protective measures for reprocessing personnel has not yet been systematically evaluated in real-world settings.

OBJECTIVE

This pilot project aimed to identify reprocessing activities that generate splashes, determine how far droplets can travel in decontamination areas, and assess personal protective equipment exposure during routine activities.

METHODS

Moisture-detection paper was affixed to environmental surfaces and personal protective equipment in a sterile processing department. Droplet dispersal was assessed after personnel simulated performance of routine reprocessing tasks.

RESULTS

Visible droplets were generated during every reprocessing activity except running the sonication sink. Droplets traveled at least 3 feet when filling a sink, brushing a ureteroscope, and using a power sprayer to rinse a basin. Some activities dispersed droplets up to 5 feet from the sink. Personal protective equipment was splashed during most activities and did not prevent skin exposure even when properly donned and doffed.

CONCLUSION

This hypothesis-generating pilot project found that routine reprocessing activities generated substantial splashing, and currently recommended personal protective equipment did not adequately protect sterile processing personnel from exposure.

Effectors of the Stenotrophomonas maltophilia Type IV Secretion System Mediate Killing of Clinical Isolates of Pseudomonas aeruginosa

Previously, we documented that Stenotrophomonas maltophilia encodes a type IV secretion system (T4SS) that allows the organism to kill, in contact-dependent fashion, heterologous bacteria, including wild-type Pseudomonas aeruginosa. Bioinformatic screens based largely on the presence of both a C-terminal consensus sequence and an adjacent gene encoding a cognate immunity protein identified 13 potential antibacterial effectors, most of which were highly conserved among sequenced strains of S. maltophilia. The immunity proteins of two of these proved especially capable of protecting P. aeruginosa and Escherichia coli against attack from the Stenotrophomonas T4SS. In turn, S. maltophilia mutants lacking the putative effectors RS14245 and RS14255 were impaired for killing not only laboratory E. coli but clinical isolates of P. aeruginosa, including ones isolated from the lungs of cystic fibrosis patients. That complemented mutants behaved as wild type did confirmed that RS14245 and RS14255 are required for the bactericidal activity of the S. maltophilia T4SS. Moreover, a mutant lacking both of these proteins was as impaired as a mutant lacking the T4SS apparatus, indicating that RS14245 and RS14255 account for (nearly) all of the bactericidal effects seen. Utilizing an interbacterial protein translocation assay, we determined that RS14245 and RS14255 are bona fide substrates of the T4SS, a result confirmed by examination of mutants lacking both the T4SS and the individual effectors. Delivery of the cloned 14245 protein (alone) into the periplasm resulted in the killing of target bacteria, indicating that this effector, a putative lipase, is both necessary and sufficient for bactericidal activity.

Water as a Source of Antimicrobial Resistance and Healthcare-Associated Infections

Healthcare-associated infections (HAIs) are one of the most common patient complications, affecting 7% of patients in developed countries each year. The rise of antimicrobial resistant (AMR) bacteria has been identified as one of the biggest global health challenges, resulting in an estimated 23,000 deaths in the US annually. Environmental reservoirs for AMR bacteria such as bed rails, light switches and doorknobs have been identified in the past and addressed with infection prevention guidelines. However, water and water-related devices are often overlooked as potential sources of HAI outbreaks. This systematic review examines the role of water and water-related devices in the transmission of AMR bacteria responsible for HAIs, discussing common waterborne devices, pathogens, and surveillance strategies. AMR strains of previously described waterborne pathogens including Pseudomonas aeruginosa, Mycobacterium spp., and Legionella spp. were commonly isolated. However, methicillin-resistant Staphylococcus aureus and carbapenem-resistant Enterobacteriaceae that are not typically associated with water were also isolated. Biofilms were identified as a hot spot for the dissemination of genes responsible for survival functions. A limitation identified was a lack of consistency between environmental screening scope, isolation methodology, and antimicrobial resistance characterization. Broad universal environmental surveillance guidelines must be developed and adopted to monitor AMR pathogens, allowing prediction of future threats before waterborne infection outbreaks occur.

Nutrients influence the dynamics of Klebsiella pneumoniae carbapenemase producing enterobacterales in transplanted hospital sinks

Antimicrobial resistance has been recognized as a threat to human health. The role of hospital sinks acting as a reservoir for some of the most concerning antibiotic resistant organisms, carbapenemase producing Enterobacterales (CPE) is evident but not well understood. Strategies to prevent establishment, interventions to eliminate these reservoirs and factors which drive persistence of CPE are not well established. We use a uniquely designed sink lab to transplant CPE colonized hospital sink plumbing with an aim to understand CPE dynamics in a controlled setting, notably exploiting both molecular and culture techniques. After ex situ installation the CPE population in the sink plumbing drop from previously detectable to undetectable levels. The addition of nutrients is followed by a quick rebound in CPE detection in the sinks after as many as 37 days. We did not however detect a significant shift in microbial community structure or the overall resistance gene carriage in longitudinal samples from a subset of these transplanted sinks using whole shotgun metagenomic sequencing. Comparing nutrient types in a benchtop culture study model, protein rich nutrients appear to be the most supportive for CPE growth and biofilm formation ability. The role of nutrients exposure is determining factor for maintaining a high bioburden of CPE in the sink drains and P-traps. Therefore, limiting nutrient disposal into sinks has reasonable potential with regard to decreasing the CPE wastewater burden, especially in hospitals seeking to control an environmental reservoir.

Complete-Genome Sequencing and Comparative Genomic Characterization of an IMP-4 Producing Citrobacter freundii Isolate from Patient with Diarrhea

Background

Citrobacter freundii is the most common class of pathogens in the genus Citrobacter and is an important pathogen associated with certain underlying diseases or immune dysfunction. The aim of this study was to elucidate the resistance mechanism of clinically derived carbapenem-resistant C. freundii isolate and to characterize the genetic environment and delivery pattern of the IncN1 plasmid carrying the bla_IMP-4 gene from C. freundii isolate.

Materials and Methods

We identified a clinical isolate of C. freundii L91 carrying bla_IMP-4 and performed phylogenetic analysis by whole-genome sequencing. The complete genomic sequence of L91 was obtained using the Illumina HiSeq 4000-PE150 and PacBio RS II platforms. Antimicrobial susceptibility testing was determined by the VITEK 2 system. Plasmid characteristics were presented by S1-pulsed-field gel electrophoresis (PFGE), Southern blotting and conjugation experiments.

Results

S1-PFGE, Southern blot and conjugation assay confirmed the presence of bla_IMP-4 genes on a conjugative plasmid in this isolate. C. freundii L91 and transconjugant L91-E. coli 600 strains both showed resistance to carbapenems. In silico analysis further showed that pIMP-4-L91 is an IncN1 plasmid with a length of 51,042 bp. Furthermore, bla_IMP-4 gene was found encoded in the bla_IMP-4-qacG2-aacA4-catB3 cassette array within a class 1 integron. A conserved structure sequence (ΔISKpn27-bla_IMP-4-ΔISSen2-hp-hp-IS6100) was found in the upstream and downstream of the bla_IMP-4.

Conclusion

We performed a comprehensive phylogenetic analysis of carbapenemase-resistant C. freundii and elucidated the resistance mechanism of clinically derived C. freundii L91. Not only that, we also found that the bla_IMP-4 gene is located on the IncN1 plasmid and has a horizontal transfer function and a certain ability to spread. To lower the risk of the dissemination of such C. freundii isolates in clinical settings, more surveillance is needed in the future.

High prevalence of contamination of sink drains with carbapenemase-producing Enterobacteriaceae in 4 intensive care units apart from any epidemic context

We report a high prevalence (28%) of sink drains contaminated with carbapenemase-producing Enterobacteriaceae (CPE) in 4 intensive care units with a history of CPE carriage in hospitalized patients within the previous 5 years, but apart from any current epidemic context. Carbapenemase genes, particularly bla_VIM and bla_NDM, were identified by polymerase chain reaction in sink drains in which no CPE was detected, but very few data are available in the literature concerning their presence in sink drains.

New Delhi Metallo-β-lactamase and other mechanisms of carbapenemases among Enterobacteriaceae in rural South India

OBJECTIVES

The emergence and dissemination of carbapenem-resistant Enterobacteriaceae (CRE) is an important public health problem. This study aimed to understand the prevalence and mechanisms of carbapenem resistance in clinically important members of Enterobacteriaceae in rural South India.

METHODS

Routine clinical isolates of Escherichia coli and Klebsiella spp. were tested for Ertapenem (ETP) non-susceptibility by the disk diffusion method over a 3-year period (2012-2014). The ETP non-susceptible isolates were preserved, and tested for the MIC of carbapenems and the carriage of major carbapenemase-encoding genes. Representative genes were sequenced and selective isolates were tested for the production of carbapenemase by carbapenem inactivation method.

RESULTS

A total of 444 ETP non-susceptible isolates were identified in increasing incidence over the study period. Among them, MIC₅₀ and MIC₉₀ of carbapenems (excluding ETP) were 0.25-0.5μg/mL and 8-16μg/mL, respectively, and the prevalence of non-ETP carbapenem resistance was estimated as 3%. Among the 177 tested isolates, 65 (37%) had one or more carbapenemase-encoding genes with a predominance of New Delhi Metallo-β-lactamase (NDM; 32 of 65; 49.2%).

CONCLUSIONS

This study documented the MIC range for carbapenems, prevalence and mechanisms of carbapenem resistance among Enterobacteriaceae in rural South India. It substantiated NDM as a leading mechanism of carbapenem resistance and highlighted the importance of MIC testing in patient management.

Special problems associated with reprocessing instruments in outpatient care facilities: Physical spaces, education, infection preventionists, industry, reflections

The infection preventionists' (IPs') presence and intervention in outpatient facilities continues to lag behind the inpatient hospital IPs' presence. Additionally, in an outpatient world that is heavy on instrument reprocessing, IPs must be prepared to assess instrument reprocessing practices, including high-level disinfection and sterilization to keep our patients and staffs safe. This paper presents 3 problems associated with instrument reprocessing practices in health care facilities, with a special emphasis on outpatient facilities: physical space problems, training and education problems, and lack of IPs' presence. We offer solutions and mitigation strategies for these 3 problems. We also give some reflections on the current state of IP presence and responsibilities, and industry responsibilities, and we call for robust partnerships between IPs and the instrument reprocessing industry.

Identification of Diverse Integron and Plasmid Structures Carrying a Novel Carbapenemase Among Pseudomonas Species

A novel carbapenem-hydrolyzing beta-lactamase, called IMP-63, was identified in three clonally distinct strains of Pseudomonas aeruginosa and two strains of Pseudomonas putida isolated within a 4 year timeframe in three French hospitals. The bla_IMP–63 gene that encodes this carbapenemase turned out to be located in the variable region of four integrons (In1297, In1574, In1573, and In1572) and to coexist with novel or rare gene cassettes (fosM, gcu170, gcuF1) and insertion elements (ISPsp7v, ISPa16v). All these integrons except one (In1574) were flanked by a copy of insertion sequence ISPa17 next to the orf6 putative gene, and were carried by non-conjugative plasmids (pNECK1, pROUSS1, pROUSS2, pROUE1). These plasmids exhibit unique modular structures and partial sequence homologies with plasmids previously identified in various non-fermenting environmental Gram-negative species. Lines of evidence suggest that ISPa17 promoted en bloc the transposition of IMP-63-encoding integrons on these different plasmids. As demonstrated by genotyping experiments, isolates of P. aeruginosa harboring the 28.9-kb plasmid pNECK1 and belonging to international “high-risk” clone ST308 were responsible for an outbreak in one hospital. Collectively, these data provide an insight into the complex and unpredictable routes of diffusion of some resistance determinants, here bla_IMP–63, among Pseudomonas species.

Droplet- Rather than Aerosol-Mediated Dispersion Is the Primary Mechanism of Bacterial Transmission from Contaminated Hand-Washing Sink Traps

An alarming rise in hospital outbreaks implicating hand-washing sinks has led to widespread acknowledgment that sinks are a major reservoir of antibiotic-resistant pathogens in patient care areas. An earlier study using green fluorescent protein (GFP)-expressing Escherichia coli (GFP-E. coli) as a model organism demonstrated dispersal from drain biofilms in contaminated sinks. The present study further characterizes the dispersal of microorganisms from contaminated sinks. Replicate hand-washing sinks were inoculated with GFP-E. coli, and dispersion was measured using qualitative (settle plates) and quantitative (air sampling) methods. Dispersal caused by faucet water was captured with settle plates and air sampling methods when bacteria were present on the drain. In contrast, no dispersal was captured without or in between faucet events, amending an earlier theory that bacteria aerosolize from the P-trap and disperse. Numbers of dispersed GFP-E. coli cells diminished substantially within 30 minutes after faucet usage, suggesting that the organisms were associated with larger droplet-sized particles that are not suspended in the air for long periods.IMPORTANCE Among the possible environmental reservoirs in a patient care environment, sink drains are increasingly recognized as a potential reservoir to hospitalized patients of multidrug-resistant health care-associated pathogens. With increasing antimicrobial resistance limiting therapeutic options for patients, a better understanding of how pathogens disseminate from sink drains is urgently needed. Once this knowledge gap has decreased, interventions can be engineered to decrease or eliminate transmission from hospital sink drains to patients. The current study further defines the mechanisms of transmission for bacteria that colonize sink drains.

A Bundle of Measures to Control an Outbreak of Pseudomonas aeruginosa Associated With P-Trap Contamination

OBJECTIVE To describe an outbreak of multidrug-resistant Pseudomonas aeruginosa in which the hospital waste-pipe system was the likely source of contamination and to report the bundle of measures that facilitated the long-term control of the outbreak. DESIGN Outbreak investigation. SETTING The hematology unit of a tertiary-care referral center. PATIENTS Patients who were colonized or infected with P. aeruginosa belonging to the clonal outbreak. METHODS Patients admitted to our 15-bed stem-cell transplantation hematology unit were screened for P. aeruginosa carriage. Pseudomonas aeruginosa isolates were also obtained from diagnostic samples. We assessed the microbiological contamination of P-traps, water and toilets for 42 months. Extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) were screened and identified by polymerase chain reaction (PCR) and sequencing. Molecular typing of ESBL- or MBL-producing isolates was carried out using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). RESULTS From 2009 to 2013, a biclonal outbreak of IMP-19-producing ST235 (11 cases) and IMP-29-producing ST111 (10 cases) of P. aeruginosa occurred. The environmental investigation strongly suggested that P-traps were the reservoirs for the outbreak strains. A bundle of infection control measures, including engineering interventions on water outlets and disinfection of P-traps, controlled the outbreak. CONCLUSIONS We report a prolonged outbreak of IMP-producing high-risk clones of P. aeruginosa, for which P-traps seems to play a major role in cross-transmission. It appears essential to implement proactive measures to limit the bacterial load in water fittings of high-risk units. Infect Control Hosp Epidemiol 2018;39:164-169.

Wastewater drains: epidemiology and interventions in 23 carbapenem-resistant organism outbreaks

For many years, patient-area wastewater drains (ie, sink and shower drains) have been considered a potential source of bacterial pathogens that can be transmitted to patients. Recently, evolving genomic epidemiology tools combined with new insights into the ecology of wastewater drain (WWD) biofilm have provided new perspectives on the clinical relevance and hospital-associated infection (HAI) transmission risks related to these fixtures. To further clarify the clinical relevance of WWD-associated pathogen transmission, reports of outbreaks attributed to WWDs were selected for review that (1) investigated the outbreak epidemiology of WWD-associated transmission of bacterial pathogens, (2) utilized advanced microbiologic methods to establish clonality of outbreak pathogens and/or resistance genes, or (3) described interventions implemented to mitigate transmission of the outbreak pathogens from WWDs. These reports were collated, compared, and analyzed, and the results are presented here.