Outbreak In Intensive Care Unit Research Articles

Serratia marcescens outbreak in a neonatal intensive care unit associated with contaminated handwashing sinks

This article describes the origin of a S. marcescens outbreak in a neonatal intensive care unit (NICU). A retrospective case-control study including 12 S. marcescens-positive and 22 S. marcescens-negative neonates in the NICU was performed to identify the source of the outbreak. S. marcescens isolates were collected during the outbreak and analyzed using whole-genome sequencing (WGS). IQ-Tree software, BEAST2 software package and SCOTTI software were used to construct a phylogenetic tree and a propagation path map. The index case occurred on February 21st and outbreak ended on March 9th, 2021, affecting a total of 12 neonates (2 with S. marcescens infection and 10 with S. marcescens colonization). Multivariate logistic regression identified that the distance of <0.8 m between the bed unit and the sink (odds ratio [OR], 20.50; 95% confidence interval [CI], 1.09-384.86), a large number of rotating nurses within a week (OR 2.58, 95% CI, 1.09-6.11) and use of humidification water in the incubator (OR 189.70, 95% CI, 2.76-13027.31) were significantly increased risk factors for S. marcescens infection or colonization in the outbreak. WGS sifted out a predominant clone between contaminated handwashing sinks and patients, suggesting that cross-transmission was involved in the dissemination of S. marcescens. Contaminated handwashing sinks can be a communication intermediary of S. marcescens infection of colonization of neonates in the NICU. A distance of <0.8 m between the bed unit and the sink, and a large number of rotating nurses might play important roles in this outbreak. Attention should be paid to sinks contamination and contact transmission to prevent outbreaks.

Outbreaks in the Neonatal Intensive Care Unit: Description and Management.

Healthcare settings, especially intensive care units, can provide an ideal environment for the transmission of pathogens and the onset of outbreaks. Many factors can contribute to the onset of an epidemic in a neonatal intensive care unit (NICU), including neonates' vulnerability to healthcare-associated infections, especially for those born preterm; facility design; frequent invasive procedures; and frequent contact with healthcare personnel. Outbreaks in NICUs are one of the most relevant problems because they are often caused by multidrug-resistant organisms associated with increased mortality and morbidity. The prompt identification of an outbreak, the subsequent investigation to identify the source of infection, the risk factors, the reinforcement of routine infection control measures, and the implementation of additional control measures are essential elements to contain an epidemic.

Complex Infection-Control Measures with Disinfectant Switch Help the Successful Early Control of Carbapenem-Resistant Acinetobacter baumannii Outbreak in Intensive Care Unit.

A carbapenem-resistant Acinetobacter baumannii (CRAB) outbreak in an intensive care unit (ICU) was contained by an improved infection-control measure that included a disinfectant policy. In our retrospective cohort study, we describe the epidemiological investigations and infection-control measures during this outbreak. Descriptive analysis was used to summarize patient demographics, neurological diseases, surgical treatment, underlying diseases, infection, and outcomes. In December 2023, two CARB-positive patients were observed in the ICU, and four more patients became CRAB-positive in January. During this outbreak, there was an overlap of hospitalization periods among the CRAB-positive patients, and CRAB was isolated from the environment; the isolated CRAB strain was identical. Infection-control measures, including hand hygiene, contact precautions and isolation, surveillance, decolonization, environmental cleaning, and disinfection, were reviewed and modified. The aim of this study was to examine the molecular background of the effectiveness of the disinfectant shift used during successful outbreak control. Experiments were carried out to study the phenotypic sensitivity and genetic background of different disinfectant agents. A thorough analysis of the detected CRAB strain included whole-genome sequencing (WGS), investigation of the qacE and qacEΔ1 genes' relative expression by qPCR after exposure to different disinfectant solutions, as well as an analysis of biofilm formation. WGS analysis of the CRAB strain identified that an ST2 high-risk clone was responsible for the outbreak, which produced OXA-83 and ADC-30 beta-lactamases; in addition, qacE and qacEΔ1 genes were also detected, which confer resistance to disinfectants containing quaternary ammonium compounds (QACs). A qPCR analysis demonstrated that after exposure to different disinfectants, the gene expression levels of qacE and qacEΔ1 increased and correlated with concentrations of QACs of disinfectants. During the outbreak, the standard-of-care QAC-based disinfectant was changed to a mainly alcohol-based agent in the ICU, which contributed to the successful control of this outbreak, and no additional patients were identified with CRAB. We conclude that continuous surveillance and hand hygiene training combined with fast identification and reaction to new cases, as well as an in-depth analysis of multidrug-resistant outbreak strains and investigation of their disinfectant tolerance/resistance during an outbreak, are essential to effectively control the spread of nosocomial pathogens. The smart policy of disinfectant agent selection played a crucial role in controlling the outbreak and ensuring patient safety in the ICU.

Infection Prevention and Control Strategies According to the Type of Multidrug-Resistant Bacteria and Candida auris in Intensive Care Units: A Pragmatic Resume including Pathogens R0 and a Cost-Effectiveness Analysis.

Multidrug-resistant organism (MDRO) outbreaks have been steadily increasing in intensive care units (ICUs). Still, healthcare institutions and workers (HCWs) have not reached unanimity on how and when to implement infection prevention and control (IPC) strategies. We aimed to provide a pragmatic physician practice-oriented resume of strategies towards different MDRO outbreaks in ICUs. We performed a narrative review on IPC in ICUs, investigating patient-to-staff ratios; education, isolation, decolonization, screening, and hygiene practices; outbreak reporting; cost-effectiveness; reproduction numbers (R0); and future perspectives. The most effective IPC strategy remains unknown. Most studies focus on a specific pathogen or disease, making the clinician lose sight of the big picture. IPC strategies have proven their cost-effectiveness regardless of typology, country, and pathogen. A standardized, universal, pragmatic protocol for HCW education should be elaborated. Likewise, the elaboration of a rapid outbreak recognition tool (i.e., an easy-to-use mathematical model) would improve early diagnosis and prevent spreading. Further studies are needed to express views in favor or against MDRO decolonization. New promising strategies are emerging and need to be tested in the field. The lack of IPC strategy application has made and still makes ICUs major MDRO reservoirs in the community. In a not-too-distant future, genetic engineering and phage therapies could represent a plot twist in MDRO IPC strategies.

Whole Genome Sequencing for the Identification of a Streptococcus agalactiae Outbreak in Neonatal Intensive Care Unit

Background: While Streptococcus agalactiae (Group B Streptococcus [GBS]) infections in infants usually result from maternal transmission, healthcare-associated cases, particularly in the neonatal intensive care unit (NICU), can occur. Whole genome sequencing (WGS) can aid in investigating GBS outbreaks among infants in hospital settings. The aim of the study is to describe the investigation of GBS infections in NICU using WGS. Methods: Infection prevention and control (IPAC) at our hospital monitors the occurrence of late-onset GBS disease (LOD) in our 57-bed NICU, which consists of all private rooms. The occurrence of 2 cases of LOD within 2 weeks triggered an investigation, including WGS of the two isolates and isolates causing invasive GBS during the last 6 months in the unit. GBS isolates underwent WGS using Illumina at Canada’s National Microbiology Laboratory. All affected patients underwent chart-review. Outbreak description and investigation: In August 2023, two NICU neonates (patients 2,3) experienced LOD two weeks apart, one with bacteremic meningitis and the other with two bacteremic episodes three weeks apart. While WGS was pending two additional cases of late-onset GBS bacteremia (patients 4,5) occurred. Isolates from Pts 2,3 and 5 were indistinguishable from each other and from an isolate from an infant admitted to the NICU with early onset bacteremia on July 27, 2023 (day 1 of life) (patient 1). Weekly point prevalence for throat and rectal colonization over 3 weeks identified five infants colonized with unrelated strains. An additional long-stay infant (patient 6) developed GBS conjunctivitis due to a strain indistinguishable from (patient 4) by pulse field gel electrophoresis, WGS for the second cluster is pending. IPAC interventions: Lapses in IPAC practices were observed, with no commonalities among cases other than similar geographic location within the unit. We hypothesized transmission was due to horizontal transmission between babies due to these lapses. Basic IPAC measures, including hand hygiene and environmental cleaning, were reinforced; Additional Precautions were not used due to private rooms’ unit structure. No environmental samples were taken due to lack of an obvious environmental point or common source. Point prevalence monitoring persisted until no new cases related to the outbreak strains were further identified in three consecutive weekly point prevalence. Conclusions: Increased awareness of healthcare-associated transmission is crucial in NICU as LOD GBS emerges. WGS plays a key role in identifying transmission. Detecting a multi-strain outbreak can appropriately redirect investigations. Legend: Figure 1: Timeline of stay at NICU and infection timing for patients 1-6

Serratia marcescens Burden in a Neonatal Intensive Care Unit: Colonization Rate, Clinical Infections and Strain Relatedness

Background: Serratia marcescens (S. marcescens) is an environmentally associated organism known for causing healthcare associated infections and outbreaks in neonatal intensive care units (NICUs). The colonization or infection rates in NICU settings remain uncertain. This study aims to evaluate the rate of baseline colonization and clinical infection and relatedness of S. marcescens isolates. Methods: Prospective surveillance of rectal colonization and clinical infection of S. marcescens was conducted on patients admitted to the NICU at Mount Sinai Hospital in Toronto, Ontario, from March 1, 2023, to September 30, 2023. The NICU is a 57 bed unit with all private rooms. Monthly point prevalence assessments by rectal screening were performed, alongside active surveillance for clinical infections associated with S. marcesens. Isolates from screening or clinical samples underwent assessment for relatedness using pulse field gel electrophoresis (PFGE). Results: Over the 7 month study period, 12 different patients (5.4%) were colonized/infected with S. marcescens. Among these, 10 patients (4.5%) were identified through rectal screening (316 rectal swabs were collected from 224 patients) and two patients (0.9%) exhibited positive clinical specimens (urine and endotracheal aspirate) in association with pyelonephritis and ventilator-associated pneumonia, respectively. Of the two clinical cases, one case showed a negative preceding rectal swab and the other detected through a clinical sample before the point prevalence date. The age at which a positive S. marcescens swab or positive clinical specimen was identified ranged from 4 to 66 days (median=18 days, IQR 5-38.8) (Figure 1). Sixty seven infants had repeated screening. Three out of 67 (4.5%) were colonized with S. marcescens, the timing and sequence of positive and negative testing are presented in Figure 2. Females demonstrated a higher positivity rate compared to males [9.1% (9/99) vs 2.4% (3/125), p=0.04, respectively]. PFGE analysis of all 12 (100%) isolates revealed a polyclonal pattern. Most cases were detected from March to May in 9/12 cases (75%). Ten different strains were identified. Notably, two strains demonstrated clusters of two cases each, one during March and the other during May (Figure 3). No mortality was reported among the cases. Conclusions: The study highlights the polyclonal nature of S. marcesens and raises questions about the utility of point prevalence in anticipating clinical cases or patient-to-patient transmission, especially in patients with clinical infection where there were no preceding positive screening tests.

Enterococcal Bacteremia outbreaks during SARS-COV-2 in Intensive Care Unit (ICU): The role of Strain Identification

Background: An unprecedented burden of morbidity and mortality has been reported in patients admitted to healthcare facilities with SARS-COV-2 infection globally since March 2020. A higher incidence of ICU-acquired bloodstream infection has been described with the cumulative risk increased with the length of ICU stay, use of steroids, anti-inflammatory agents, and indwelling catheters. Additionally, SARS-COV-2 infection may increase the risk of bacteremia from gastrointestinal flora such as Enterococcus species by disrupting the gastrointestinal barrier and microbiome. Methods: We aimed to investigate the outbreaks of Enterococcus bacteremia in patients with SARS-COV-2 infection and included patients aged&gt;18 years admitted to the ICU at the Oklahoma City Veterans Affairs Medical Center who were infected with SARS-COV-2 and were identified as having positive blood cultures for Enterococcus faecalis, Enterococcus faecium including vancomycin-resistant species and other bacterial or candida species between March 1, 2020, to March 9, 2022. We collected the following data: duration of hospitalization including ICU stay, unit and room location during the hospital stay, blood culture collection date and results, duration, and site of central line placement, duration of ventilation, administration of antimicrobials and COVID-19 directed therapeutics using computerized patient record system (CPRS). We sent 10 E. faecalis and 12 E. Faecium isolates for genetic analysis. DNA was sequestered from each isolate and multi-locus sequence typing (MLST) was performed by amplifying 7 regions of the E. faecalis genome and 7 regions of the E. faecium genome by polymerase chain reaction (PCR). Resulting amplicons were sequenced and allele type for each gene region and overall sequence type was determined using MLST database (http://pubmlst.org). Results: There were 22 episodes of enterococcal bacteremia in a 3-month duration in the ICU in 20 patients of which 17 were associated with another episode with the same strain (Figure-1-2). Central line placement was noted in 18/22 episodes. Genetic analysis by multi-locus sequence typing of enterococcal bacterial strains was performed by the Public Health Reference Laboratory, Palo Alto. Similar strains were localized to patients in the same geographical region in the ICU (Figure 3). The isolates from 2 other patients who presented with the same strain of Enterococcus but were never hospitalized at the same time during the COVID-19 pandemic were localized to another hospital where both had received care at different times. Conclusion: Higher rates of enterococcal bacteremia were reported during the SARS-COV-2 pandemic. Geographical proximity with strained infection control measures accounted for ICU outbreaks seen in our tertiary care setup.

Core genome multilocus sequence typing (cgMLST) applicable to the monophyletic Klebsiella oxytoca species complex.

The environmental bacterium Klebsiella oxytoca displays an alarming increase of antibiotic-resistant strains that frequently cause outbreaks in intensive care units. Due to its prevalence in the environment and opportunistic presence in humans, molecular surveillance (including resistance marker screening) and high-resolution cluster analysis are of high relevance. Furthermore, K. oxytoca previously described in studies is rather a species complex (KoSC) than a single species comprising at least six closely related species that are not easily differentiated by standard typing methods. To reach a discriminatory power high enough to identify and resolve clusters within these species, whole genome sequencing is necessary. The resolution is achievable with core genome multilocus sequence typing (cgMLST) extending typing of a few housekeeping genes to thousands of core genome genes. CgMLST is highly standardized and provides a nomenclature enabling cross laboratory reproducibility and data exchange for routine diagnostics. Here, we established a cgMLST scheme not only capable of resolving the KoSC species but also producing reliable and consistent results for published outbreaks. Our cgMLST scheme consists of 2,536 core genome and 2,693 accessory genome targets, with a percentage of good cgMLST targets of 98.31% in 880 KoSC genomes downloaded from the National Center for Biotechnology Information (NCBI). We also validated resistance markers against known resistance gene patterns and successfully linked genetic results to phenotypically confirmed toxic strains carrying the til gene cluster. In conclusion, our novel cgMLST enables highly reproducible typing of four different clinically relevant species of the KoSC and thus facilitates molecular surveillance and cluster investigations.

Implications of ad-hoc molecular typing for infection control measures in a multi-cluster, multi-phenotypic Serratia marcescens outbreak in a neonatal intensive care unit

Serratia marcescens is known to cause outbreaks in Neonatal Intensive Care Units (NICU). Traditionally epidemiological data, antimicrobial resistance patterns and epidemiological typing are being used to guide infection prevention methods. Whole genome sequencing (WGS) applications such as core-genome multi-locus sequence typing (cgMLST) applied during an outbreak would potentially give more detailed information on the source and spread of bacteria enabling more efficient control measures. CgMLST was used during an S. marcescens outbreak at a NICU. Neonates admitted to the NICU of the Leiden University Medical Center (LUMC) during an outbreak between September 2023-January 2024, with S. marcescens being cultured were included. Environmental samples were taken to search for a common source, antibiotic susceptibility testing was performed, and antimicrobial resistances genes were analysed. S. marcescens strains from 17 of the 20 positive patients were available for molecular typing. The cgMLST scheme revealed five different complex types consisting of four separate clusters. Multiple clusters made an unidentified persistent environmental source as cause of the outbreak less likely, leading to a quick downscaling of infection prevention measures. Differences were shown in aminoglycoside resistance patterns of isolates within the same complex types and patients. The use of ad-hoc cgMLST provided timely data for rational decision making during an S. marcescens outbreak at the NICU. Antibiotic phenotyping alone was found not to be suitable for studying clonal spread during this outbreak with S. marcescens.

Evolution, control and success of combination therapy with Ampicilin-sulbactam/Ceftazidime-Avibactam during a Carbapenem-Resistant Acinetobacter baumannii outbreak in burn Intensive Care Unit.

We present our findings on interpatient transmission, epidemic control measures, and the outcomes of a series of ten critically ill burn patients who were either colonized or infected with carbapenem-resistant Acinetobacter baumannii (CRAB). None of the five infected patients achieved clinical cure, and all experienced relapses. Microbiological failure was observed in 40% of the infected patients. The isolated CRAB strains were found to carry blaOXA-23 and armA resistance genes. Despite the lack of clinical cure, all five infected patients survived and were discharged from the Burn Intensive Care Unit.

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.

COVID-19 Outbreak in a Neonatal Intensive Care Unit During Third Pandemic Wave: A Case Series

The case series aims to provide insights into the clinical presentation, diagnosis, management, and outcomes of neonates infected with COVID-19 during the third wave. We highlight the unusual clinical features, especially incessant cough even in extremely premature neonates, and the mode of horizontal transmission that led to this outbreak. A high index of suspicion and timely diagnosis of COVID-19 in neonates can help avoid the overdiagnosis of clinical sepsis and limit the inadvertent use of antibiotics. The report adds valuable information to the literature for clinicians caring for neonates during the ongoing COVID-19 pandemic.

Investigating environmental transmission to resolve a Bacillus cereus group outbreak in a neonatal intensive care unit using core genome multilocus sequence typing

BackgroundWe analyzed an outbreak of Bacillus cereus group (Bcg) at a single-center neonatal intensive care unit level IV by conducting comprehensive sampling of both patients and the environment.MethodsBetween 06/2020 and 10/2021, all Bcg isolates identified by both regular colonization screening and additional sampling of the environment were subjected to whole-genome sequencing, followed by in vitro extraction of MLST ST, resistance genes and virulence factors. Using publicly available genome sequences, we defined an ad hoc core genome multilocus sequence typing (cgMLST) scheme comprising 2759 target genes for Bcg typing, which we applied to the detected isolates. We have compared the results with a stable cgMLST that was published in the meantime and completed the investigation with a SNP analysis.ResultsWe analyzed 28 Bcg isolates from patient and environmental samples using MLST and cgMLST. This revealed multiple sequence types, with ST127 being the most common (n = 13). Both cgMLST schemes grouped ten of the 13 ST127 isolates into a cluster, including two invasive isolates from two different patients and several environmental samples. SNP analysis postulated a screen from a ventilation machine as a possible reservoir.ConclusionIn sensitive settings such as neonatal intensive care units, considering the environment in outbreak analyses is crucial, especially when investigating potential transmission routes through shared devices. When dealing with widespread bacteria such as Bcg, high-resolution typing techniques are necessary. In this study, we successfully resolved an outbreak of Bcg infections using a custom cgMLST scheme combined with a SNP analysis.

Staphylococcal aureus outbreaks in neonatal intensive care units: strategies, nuances, and lessons learned from the frontline.

Methicillin-resistant Staphylococcus aureus (MRSA) infections in neonates can result in significant morbidity and mortality. However, comparatively to adults, neonatal MRSA data remains relatively scarce. Additionally, while evidence-driven practices for adults have seen considerable progress, neonatal infection prevention strategies remain poorly described. The Leeds Newborn Service adopted a series of infection prevention and control (IPC) measures following a rise in MRSA cases in 2008-2009. This narrative review presents IPC measures for neonatal MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) infections and reflects upon local challenges and successes of these interventions. Our experience underscores the importance of an adaptive, evidence-based strategy, tailored to the neonatal population. Effectively addressing MRSA/MSSA requires continuous monitoring with sustained targeted interventions. Our key learning points highlight the intertwined difficulties of specific neonatal requirements and lack of definitive IPC guidance, suggesting a holistic approach is key for successful IPC outcomes in the neonatal intensive care unit setting.

WGS Analysis of Staphylococcus warneri Outbreak in a Neonatal Intensive Care Unit.

Staphylococcus warneri is an opportunistic pathogen responsible for hospital-acquired infections (HAIs). The aim of this study was to describe an outbreak caused by S. warneri infection in a neonatal intensive care unit (NICU) and provide investigation, prevention and control strategies for this outbreak. We conducted an epidemiological investigation of the NICU S. warneri outbreak, involving seven neonates, staff, and environmental screening, to identify the source of infection. WGS analyses were performed on S. warneri isolates, including species identification, core genome single-nucleotide polymorphism (cgSNP) analysis, pan-genome analysis, and genetic characterization assessment of the prevalence of specific antibiotic resistance and virulence genes. Eight S. warneri strains were isolated from this outbreak, with seven from neonates and one from environment. Six clinical cases within three days in 2021 were linked to one strain isolated from environmental samples; isolates varied by 0-69 SNPs and were confirmed to be from an outbreak through WGS. Multiple infection prevention measures were implemented, including comprehensive environmental disinfection and stringent protocols, and all affected neonates were transferred to the isolation wards. Following these interventions, no further cases of S. warneri infections were observed. Furthermore, pan-genome analysis results suggested that in human S. warneri may exhibit host specificity. The investigation has revealed that the outbreak was linked to the milk preparation workbench by the WGS. It is recommended that there be a stronger focus on environmental disinfection management in order to raise awareness, improve identification, and prevention of healthcare-associated infections that are associated with the hospital environment.

Myroides odoratimimus: a New Threat with Persistent Infections, Multidrug Resistance, and the Potential for Hospital Outbreaks.

Myroides species have recently been reported more frequently in outbreaks in clinics and intensive care units (ICUs). In this study, we aimed to investigate the epidemic potential, antibiotic resistance profile, and risk factors of M. odoratimimus isolates that are increasingly being isolated from the ICUs of our hospital. Data from patients whose Myroides spp. were isolated from their clinical specimens over a 5-year period (September 2016 to January 2022) were retrospectively analyzed. Bacterial identification was performed using a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of antibiotic resistance genes was analyzed using polymerase chain reaction (PCR). Possible clonal associations between isolates were investigated using enterobacterial repetitive intergenic consensus (ERIC)-PCR. As a result, 66 isolates were identified as M. odoratimimus and one isolate was identified as M. odoratus. The blaMUS resistance gene was detected in all M. odoratimimus isolates, whereas sul2 was detected in ten isolates and tetX was detected in 11 isolates. No other resistance genes, such as blaTUS, were detected. Additionally, two different clonal association patterns were discovered in the 24 selected isolates through the ERIC-PCR method. The increase in the immunosuppressive patient population indicate the possibility of encountering this agent and other opportunistic pathogens more frequently in the future.

1679. Successful Control of MSSA Bacteremia Outbreak in Neonatal Intensive Care Unit

Abstract Background Staphylococcus aureus outbreaks in the neonatal intensive care units (NICU) have been reported with the great majority due to methicillin-resistant Staphylococcus aureus. We describe successful control of an outbreak caused by methicillin-susceptible S. aureus (MSSA) in the NICU. Methods We report a MSSA bacteremia outbreak which occurred in the NICU at a tertiary level hospital from November 29, 2020 to January 6, 2021. Molecular typing of MSSA isolates were performed including multi-locus sequence typing (ST) and spa typing. Results A total of 5 MSSA bacteremia cases occurred in 39 days. Outbreak investigation was initiated after the 5th case. Infection control measures, including isolation of cases, contact precaution and universal 0.5% chlorhexidine bathing of all NICU patients, were implemented. Surveillance cultures of patients (n=36) and health care workers (HCW) (n=60) were performed. Excluding bacteremia patients, 13% (4/31) of neonates and 32% (19/60) of HCW were identified as MSSA nasal carriers and targeted decolonization with intranasal mupirocin was performed. After implementation of control measures and decolonization, there were no new cases. Molecular analysis identified two strains [ST15 spa type t593 (n=3) and ST101 spa type t4171 (n=2)] as the cause of this bacteremia outbreak. Among MSSA nasal carriers, all 4 neonates colonized the ST15 spa t593 strain. ST15 spa t593 strain was also colonized in one HCW, however antibiotic susceptibility pattern differed. The rest of HCWs colonized many different types of MSSA. All MSSA isolates were negative for Panton-Valentine Leucocidin toxin gene. Conclusion Molecular analysis identified two different MSSA strains in this outbreak. MSSA colonization was prevalent among HCWs, however molecular analysis showed variance in distribution. Although outbreak strains were not found in HCWs, one strain was colonized among other neonates, suggesting horizontal transmission and potential of further cases. The outbreak was successfully controlled with reinforcement of precautions, universal chlorhexidine bathing and surveillance cultures with targeted decolonization. Early recognition and prompt implementation of control measures are important for outbreak control in NICU. Disclosures All Authors: No reported disclosures

Investigation of air dispersal during a rhinovirus outbreak in a pediatric intensive care unit

While airborne transmission of rhinovirus is recognized in indoor settings, its role in hospital transmission remains unclear. We investigated an outbreak of rhinovirus in a pediatric intensive care unit (PICU) to assess air dispersal. We collected clinical, environmental, and air samples, and staff's surgical masks for viral load and phylogenetic analysis. Hand hygiene compliance and the number of air changes per hour in the PICU were measured. A case-control analysis was performed to identify nosocomial rhinovirus risk factors. Between March 31, 2023, and April 2, 2023, three patients acquired rhinovirus in a cubicle (airchangesper hour: 14) of 12-bed PICU. A portable air-cleaning unit was placed promptly. Air samples (72,000L in 6hours) from the cohort area, and outer surfaces of staff's masks (n=8), were rhinovirus RNA-negative. Hand hygiene compliance showed no significant differences (31/34, 91.2% vs 33/37, 89.2%, P=1) before and during outbreak. Only 1 environmental sample (3.8%) was positive (1.86×103 copies/mL). Case-control and next-generation sequencing analysis implicated an infected staff member as the source. Our findings suggest that air dispersal of rhinovirus was not documented in the well-ventilated PICU during the outbreak. Further research is needed to better understand the dynamics of rhinovirus transmission in health care settings.

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

Between 2018 and 2022, a Belgian tertiary care hospital faced a growing issue with acquiring carbapenemase-producing organisms (CPO), mainly VIM-producing P.aeruginosa (PA-VIM) and NDM-producing Enterobacterales (CPE-NDM) among hospitalized patients in the adult intensive care unit (ICU). To investigate this ICU long-term CPO outbreak involving multiple species and a persistent environmental reservoir. Active case finding, environmental sampling, whole-genome sequencing (WGS) analysis of patient and environmental strains, and implemented control strategies were described in this study. From 2018 to 2022, 37 patients became 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. 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.

Application of Next-Generation Sequencing to Enterobacter Hormaechei Subspecies Analysis during a Neonatal Intensive Care Unit Outbreak.

The Enterobacter cloacae complex (ECC) species are potential neonatal pathogens, and ECC strains are among the most commonly encountered Enterobacter spp. associated with nosocomial bloodstream infections. Outbreaks caused by ECC can lead to significant morbidity and mortality in susceptible neonates. At the molecular level, ECC exhibits genomic heterogeneity, with six closely related species and subspecies. Genetic variability poses a challenge in accurately identifying outbreaks by determining the clonality of ECC isolates. This difficulty is further compounded by the limitations of the commonly used molecular typing methods, such as pulsed field gel electrophoresis, which do not provide reliable accuracy in distinguishing between ECC strains and can lead to incorrect conclusions. Next-generation sequencing (NGS) offers superior resolution in determining strain relatedness. Therefore, we investigated the clinical pertinence of incorporating NGS into existing bundle measures to enhance patient management during an outbreak of ECC in a level-3 neonatal intensive care unit (NICU) in Germany. As the standard of care, all neonates on the NICU received weekly microbiological swabs (nasopharyngeal and rectal) and analysis of endotracheal secretion, where feasible. During the 2.5-month outbreak, colonisation with ECC was detected in n = 10 neonates. The phylogenetic relationship and potential antimicrobial resistance genes as well as mobile genetic elements were identified via bacterial whole-genome sequencing (WGS) using Illumina MiSeq followed by in silico data analysis. Although all ECC isolates exhibited almost identical antimicrobial susceptibility patterns, the WGS data revealed the involvement of four different ECC clones. The isolates could be characterised as Enterobacter hormaechei subspecies steigerwaltii (n = 6, clonal), subsp. hoffmannii (n = 3, two clones) and subsp. oharae (n = 1). Despite the collection of environmental samples, no source of this diffuse outbreak could be identified. A new standardised operating procedure was implemented to enhance the management of neonates colonised with MRGN. This collaborative approach involved both parents and medical professionals and successfully prevented further transmission of ECC. Initially, it was believed that the NICU outbreak was caused by a single ECC clone due to the similarity in antibiotic resistance. However, our findings show that antibiotic susceptibility patterns can be misleading in investigating outbreaks of multi-drug-resistant ECC. In contrast, bacterial WGS accurately identified ECC at the clonal level, which significantly helped to delineate the nature of the observed outbreak.