Staphylococcus argenteus belongs to the Staphylococcus aureus complex and causes similar disease. Methicillin-resistant S. argenteus (MRSArg) is rare in the Netherlands. We describe the first hospital outbreak and its management. After a healthcare worker linked to a patient with MRSArg bacteremia tested positive, cohort screening of healthcare workers, patients, and family members was performed. Carriers received eradication therapy. Whole-genome multilocus sequence typing (wgMLST) and antimicrobial susceptibility testing were used to characterize isolates and mupirocin resistance. Fifteen (2.6

We investigated the genomic epidemiology of Ambler class C (AmpC-type) β-lactamases in Enterobacter cloacae complex and Klebsiella aerogenes in the national carbapenemase-producing Enterobacterales (CPE) surveillance of the Netherlands between 2012 and 2023. A total of 399 E. cloacae complex and K. aerogenes isolates from 399 patients were analyzed using whole-genome sequencing to assess genetic relatedness, resistance genes, porin, and AmpC-regulatory gene profiles, plasmid replicons, and the genomic location of AmpC-genes, respectively. Of the 399 patients, 217 were male (54

Since 2003, methicillin-resistant Staphylococcus aureus clonal complex 398 (MRSA- CC398) emerged in livestock. To assess possible transfer of resistant strains, animal-related MRSA- CC398 were characterized and compared to those from humans. For that purpose, MRSA-CC398 isolates (n = 2,569) from the national human MRSA surveillance (n = 1,758) and animal-related isolates (n = 811) were included for analysis. Next-generation sequencing data were used for MLST, whole-genome MLST (wgMLST) and identification of resistance/virulence genes. wgMLST showed that animal- and human-related MRSA-CC398 isolates grouped together in four groups termed A (n = 205), B (n = 308), C (n = 382), and D (n = 1,674) varying 103–139 wgMLST alleles between groups. Some animal-related isolates were closely related to human isolates or to animal isolates from other farms in all four groups. There were no groups containing animal isolates only. Differences were identified in the prevalence of virulence- and resistance genes between MRSA-CC398 originating from human- and animal-related isolates and between the four groups. Specifically, one branch within group C comprised only MRSA-CC398 from humans; these isolates were often ST1232, and carried lukS-PV/lukF-PV (PVL)-, sak, scn, ant(9)-Ia, and erm(A)-variant genes. Persons carrying this lineage rarely reported professional livestock contact, lived in areas with low pig density, and had more often a clinical infection compared to persons carrying non-ST1232. The MRSA-CC398 population in the Netherlands is diverse and comprised of four groups with distinct genomic signature. Although most MRSA-CC398 are still livestock-associated, a PVL-positive human-related lineage in CC398 has emerged in the Netherlands among the population in the absence of livestock contact.

BACKGROUND:Recent reports indicate a significant rise in carbapenem-resistant Providencia stuartii (CRPS) infections across Europe. OBJECTIVES:This study characterizes a CRPS strain (Ps5822) isolated from a Ukrainian refugee, in a Portuguese hospital, and examine its phylogenetic placement within the global P. stuartii population. METHODS:The Ps5822 isolate was subjected to antimicrobial susceptibility testing (AST) along with whole-genome sequencing to detect antimicrobial resistance gene detection and replicon types. Additionally, all available P. stuartii genomes from the ENA and NCBI databases (N = 585) were downloaded to assess the phylogenetic positioning of Ps5822 within the global P. stuartii population. RESULTS:AST showed only cefiderocol and aztreonam as viable therapeutic options. Phylogenetic positioning of global P. stuartii genomes revealed that (1) Ps5822, NDM-1-producing, is clustered with 28 European CRPS strains linked to soldiers and refugees medically evacuated from the Ukrainian war and (2) that winged insect and wastewater treatment plants are important reservoirs of CRPS. CONCLUSIONS:These findings support that this extensive drug-resistant P. stuartii clone originated in Ukraine and spread by subsequent population movements. This study also emphasizes the widespread dissemination of CRPS isolates among clinical, environmental, and Conflict-Linked Reservoirs.

We investigated the genomic epidemiology of carbapenem-resistant Acinetobacter baumannii (CRAb) during two surveillance periods: 2015-2017 (pilot 1) and 2022-2024 (pilot 2) in an international context to identify potential circulating high-risk lineages in the Netherlands. A total of 204 CRAb isolates were all analyzed by the carbapenem inactivation method, meropenem Etest, and whole-genome sequencing (combining Illumina and Nanopore). Comparative resistome, multilocus sequence typing (MLST), and whole-genome MLST (wgMLST) analyses were performed between pilots and compared to 577 international CRAb genomes. The Dutch CRAb population remained genetically diverse and stable between pilots and was dominated by international clone (IC)2 (61.8%), followed by IC9 (11.3%), IC1 (6.4%), and IC6 (5.9%). Also, epidemiological and clinical characteristics remained stable across both pilots. In contrast, CRAb in patients from Ukraine was genetically diverse and an epidemiologically distinct group. wgMLST indicated an increase in genetic clustering in 2022-2024, with unique CRAb clusters associated with Ukrainian patients. Of 26 identified clusters, 69% were linked to international sources. Differences in resistomes were observed between CRAb in patients from the Netherlands and Ukraine, and between pilots. Overall, 75% of isolates harbored blaOXA-23-like genes, and blaNDM genes increased from 16% to 21%. None of the CRAb isolates from Ukrainian patients carried blaNDM genes; instead, they harbored blaOXA-23-like and blaOXA-24-like genes. Hybrid assemblies showed that carbapenemase genes were predominantly chromosomal. In conclusion, CRAb in the Netherlands showed genetic stability over time, yet the presence of New Delhi metallo-β-lactamase-carbapenemases and import of strains from high-risk regions underline the necessity for ongoing national surveillance.IMPORTANCEIn 2015-2017 and 2022-2024, pilot surveillance of carbapenem-resistant Acinetobacter baumannii (CRAb) was performed in the Netherlands. Three distinct groups were compared based on epidemiological and genomic data: CRAb from 2015 to 2017 and for the 2022-2024 period, CRAb in patients from the Netherlands, and CRAb in patients from Ukraine in the Netherlands. The genomic epidemiology of CRAb has been mostly stable between 2015-2017 and 2022-2024 but seems to be strongly affected by the introduction of CRAb from foreign countries. A proportion of the 2022-2024 isolates were from Ukrainian patients. The resistance genes of CRAb from Ukrainian patients were different from those of the Netherlands. CRAb in the Netherlands are acquiring New Delhi metallo-β-lactamase-carbapenemase genes, aided by the introduction of CRAb from foreign countries. Healthcare professionals should remain aware of the risk of hospitalization in a high-risk country and the potential secondary transmission of CRAb to patients in countries with a low prevalence of this organism.

Hypervirulent Klebsiella pneumoniae species complex (hvKp) can cause invasive infections with spontaneous abscesses, also in previously healthy individuals. In contrast to Asia, hvKp is considered rare in Europe but has received more attention in the last few years, especially carbapenemase-producing strains. The aim of this prospective survey was to determine the occurrence and clinical, epidemiological, and genomic characteristics of K. pneumoniae species complex (KpSC) infections leading to spontaneous abscesses in Dutch patients. All Dutch medical microbiology laboratories (n = 51) were requested to submit KpSC isolates from 2022, that were suspected to be hypervirulent based on clinical criteria, with a spontaneous abscess as the most important criterium. Short-read sequencing (also combined with long-read sequencing for hybrid assemblies) was performed to analyze virulence factors and antimicrobial resistance genes and genetic relatedness by whole-genome multilocus sequence typing (wgMLST). In total, 33 KpSC isolates from 33 patients were submitted of whom 64% had a liver abscess and 64% had bacteremia. Among 31 patients with comorbidity information, 48% had no comorbidity. Isolates were susceptible to commonly used antibiotics. Six (18%) isolates did not have the salmochelin, yersiniabactin, aerobactin, colibactin, rmpADC, or rmpA2 gene (clusters). Thirty-six percent of isolates had a maximum Kleborate virulence score. Thirty percent were ST23. WgMLST of the isolates showed low genetic relatedness compared to each other and to 720 international hypervirulent and/or ST23 KpSC isolates from NCBI. In conclusion, this study suggests that hvKp strains do occur but are relatively uncommon in Dutch patients and differ from international strains. No carbapenemase-producers were found among study isolates. When existing microbiological/molecular definitions would be used, several spontaneous abscesses could not be explained. IMPORTANCE:Hypervirulent Klebsiella pneumoniae species complex (hvKp) can lead to severe infections with abscesses in previously healthy individuals. HvKp is considered rare in Europe but has received more attention recently. A complicating factor is the absence of a clear microbiological/molecular definition of hvKp. The aim of this survey was to determine occurrence and characteristics of K. pneumoniae species complex (KpSC) infections leading to spontaneous abscesses, suggestive of hvKp, in Dutch patients. Dutch medical microbiology laboratories were requested to submit KpSC isolates cultured in 2022 from patients with spontaneous abscesses. This study suggests that hvKp is relatively uncommon in Dutch patients with only 33 collected isolates. The isolates were susceptible to commonly used antibiotics. Genetic characteristics were very diverse. We found low genetic relatedness compared to each other and to international hvKp isolates. When existing microbiological/molecular definitions of hvKp would be used, several spontaneous abscesses from this study could not be explained.

In seven EU/EEA countries, the emergence of NDM-5-producing Enterobacter hormaechei ST1344 among patients has been detected. In minimum spanning tree analysis of core genome-multilocus sequence-typing (cgMLST) profiles, isolates cluster with ≤ 4 allelic differences. The outbreak includes 57 cases (29 female/28 male; median age: 73 years), which occurred between March 2025 and April 2026. Many were hospitalised (n = 45), some with extensive prior medical treatment, and only three reported travel abroad. A cross-border investigation, including coordinated exposure questionnaires, has not yet identified a source.

We investigated the genomic epidemiology of Ambler class C (AmpC-type) β-lactamases in Enterobacter spp. and Klebsiella aerogenes in the national carbapenemase-producing Enterobacterales (CPE) surveillance of the Netherlands between 2012 and 2023. A total of 399 E. cloacae complex and K. aerogenes isolates from 399 patients were analyzed using whole-genome sequencing to assess genetic relatedness, resistance gene profiles, plasmid replicons, and the genomic location of AmpC-genes, respectively. Of the 399 patients, 217 were male (54%), and the median age was 67 years. Carbapenemase production was assessed using the carbapenem inactivation method (CIM) and CarbaNP-test. Considerable proportions of Enterobacter spp. (32%) and K. aerogenes (52%) isolates produced carbapenemase, without detectable major carbapenemase genes (IMP, KPC, NDM, OXA-48-like, VIM), a phenotype termed CIM+Carba-. These isolates were mostly (82%) susceptible (EUCAST ≤2mg/L) to meropenem. The majority of CIM+Carba+ isolates with major carbapenemase genes were gained from pre-emptive screening, while CIM+Carba-isolates were mainly taken for diagnostic purposes. Genomic analysis identified 18 genogroups, with E. kobei , E. roggenkampii , E. ludwigii, and K. aerogenes showing the CIM+Carba-phenotype, correlating with chromosome-encoded AmpC-type β-lactamases like bla ACT-28, bla ACT-52, bla MIR-3, bla MIR-11 or ampC of which the majority (63%) yielded a positive CarbaNP. These CIM+Carba-isolates carried only few plasmids, and there was limited nosocomial spread. CIM+Carba- E. kobei carrying bla ACT-28 overproduced ACT-28 protein in the CIM. Overall, the Enterobacter and K. aerogenes population in the Netherlands is genetically diverse, with most isolates carrying species-specific AmpC-type β-lactamases with putative carbapenemase activity and represent a low-risk for public health. Importance CPE represents an important healthcare problem worldwide. This study highlights the diverse genetic Enterobacter spp. population in the Dutch CPE surveillance with E. hormaechei subsp. steigerwaltii as the most common carbapenemase-producing (CIM+Carba+) species. However, a significant proportion of E. kobei , E. roggenkampii , E. ludwigii, and K. aerogenes obtained in the Netherlands carry chromosomal AmpC-type β-lactamases with putative carbapenemase activity in the absence of major carbapenemases (CIM+Carba-), were mostly susceptible for meropenem, and showed limited nosocomial spread. We recommend whole-genome sequencing for accurate Enterobacter / K. aerogenes species classification, and AmpC-type β-lactamase gene identification. Despite limited carbapenem resistance and dissemination, proper infection control measures are necessary. The work outlined here underscores the importance of distinguishing E. kobei , E. roggenkampii , E. ludwigii, and K. aerogenes isolates and its AmpC-type β-lactamases from true CPE by whole-genome sequencing to avoid misclassification and unnecessary infection prevention and public health interventions. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The bacterial samples were obtained during regular patient care and did not require patient informed consent. The bacterial isolates are de-identified and can not be tracked to the patient and were used for national surveillance purposes only. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Both raw NGS and Nanopore long-read sequence data are available at the sequence read archive (SRA; PRJEB35685, PRJNAB903550, PRJNA1076808 and PRJNA1122997).

AbstractWe investigated the genomic epidemiology of Ambler class C (AmpC-type) β-lactamases inEnterobacterspp. andKlebsiella aerogenesin the national carbapenemase-producing Enterobacterales (CPE) surveillance of the Netherlands between 2012 and 2023. A total of 399E. cloacaecomplex andK. aerogenesisolates from 399 patients were analyzed using whole-genome sequencing to assess genetic relatedness, resistance gene profiles, plasmid replicons, and the genomic location of AmpC-genes, respectively. Of the 399 patients, 217 were male (54%), and the median age was 67 years. Carbapenemase production was assessed using the carbapenem inactivation method (CIM) and CarbaNP-test. Considerable proportions ofEnterobacterspp. (32%) andK. aerogenes(52%) isolates produced carbapenemase, without detectable major carbapenemase genes (IMP, KPC, NDM, OXA-48-like, VIM), a phenotype termed CIM+Carba-. These isolates were mostly (82%) susceptible (EUCAST ≤2mg/L) to meropenem. The majority of CIM+Carba+ isolates with major carbapenemase genes were gained from pre-emptive screening, while CIM+Carba-isolates were mainly taken for diagnostic purposes. Genomic analysis identified 18 genogroups, withE. kobei,E. roggenkampii,E. ludwigii,andK. aerogenesshowing the CIM+Carba-phenotype, correlating with chromosome-encoded AmpC-type β-lactamases likeblaACT-28,blaACT-52,blaMIR-3,blaMIR-11orampCof which the majority (63%) yielded a positive CarbaNP. These CIM+Carba-isolates carried only few plasmids, and there was limited nosocomial spread. CIM+Carba-E. kobeicarryingblaACT-28overproduced ACT-28 protein in the CIM. Overall, theEnterobacterandK. aerogenespopulation in the Netherlands is genetically diverse, with most isolates carrying species-specific AmpC-type β-lactamases with putative carbapenemase activity and represent a low-risk for public health.ImportanceCPE represents an important healthcare problem worldwide. This study highlights the diverse geneticEnterobacterspp. population in the Dutch CPE surveillance withE. hormaecheisubsp.steigerwaltiias the most common carbapenemase-producing (CIM+Carba+) species. However, a significant proportion ofE. kobei,E. roggenkampii,E. ludwigii,andK. aerogenesobtained in the Netherlands carry chromosomal AmpC-type β-lactamases with putative carbapenemase activity in the absence of major carbapenemases (CIM+Carba-), were mostly susceptible for meropenem, and showed limited nosocomial spread. We recommend whole-genome sequencing for accurateEnterobacter/K. aerogenesspecies classification, and AmpC-type β-lactamase gene identification. Despite limited carbapenem resistance and dissemination, proper infection control measures are necessary. The work outlined here underscores the importance of distinguishingE. kobei,E. roggenkampii,E. ludwigii,andK. aerogenesisolates and its AmpC-type β-lactamases from true CPE by whole-genome sequencing to avoid misclassification and unnecessary infection prevention and public health interventions.

The Russia-Ukraine war lead to evacuation of patients across Europe. We present an unprecedented case of a severely injured Ukrainian soldier carrying 11 carbapenemase-producing Enterobacterales, two carbapenemase-producing Pseudomonas aeruginosa and one carbapenem-resistant Acinetobacter baumannii, together harboring six different carbapenemase genes and with evidence for in-patient transfer of resistance plasmids.

Wastewater-based surveillance is gaining interest worldwide as a complementary tool informing human surveillance of pathogens, among which are antibiotic-resistant bacteria. The current study investigated whether CPE detected within the Dutch human CPE surveillance could be identified among isolates that were independently retrieved from Dutch wastewater. Whole genomes of 203 wastewater- and 1278 human-retrieved isolates were compared using whole-genome multilocus sequence typing (wgMLST), resistome, and plasmid analyses. Overall, 25 clusters (16 E. coli, 9 K. pneumoniae) with genetically highly related variants from both niches were detected. The maximum allelic difference between human- and wastewater-derived isolates in clusters was on average 0.51% (23/4503 alleles, E. coli) and 0.22% (11/4978 alleles K. pneumoniae). For seven clusters, in-depth plasmid analysis was performed, showing highly homologous (87-100%) carbapenemase-containing plasmids from human- and wastewater-retrieved isolates. Six clusters contained wastewater and human isolates that were spatiotemporally related. The sequence identity at chromosomal and plasmid level confirms the presence of human-associated CPE variants in wastewater. Ongoing comparisons between isolates from the national human CPE surveillance and wastewater surveillance will shed more light on the added value of wastewater-based surveillance for monitoring of CPE and other (emerging) antibiotic resistances.

An investigation of the European Antimicrobial Resistance Genes Surveillance Network (EURGen-Net) detected the same mosaic IncHI1B(pNDM-MAR) resistance (OXA-48) and virulence (aerobactin) plasmid in 492 Klebsiella pneumoniae isolates from eight European Union countries during 2019–2024. Involvement of various K. pneumoniae sequence types (STs), multiple introductions, followed by large clonal outbreaks of three STs (ST147, ST392, ST45) carrying the plasmid in two countries indicate a high risk for further spread of this plasmid and a potential for difficult-to-treat K. pneumoniae infections to rise.

OBJECTIVES:The objective of this collaborative surveillance project was to investigate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among livestock farms, persons working/living on these farms, and on meat. METHODS:Samples from Dutch broiler, pig, veal calf, dairy cattle, and sheep farms, persons living/working on these farms and retail meat collected between 2018 and 2023 were cultured using (pre-) enrichment and selective plates. Next-generation sequencing of a subset of MRSA was performed to detect mecA/mecC, Panton-Valentine leucocidin (PVL) and to assign genogroups (GGs). RESULTS:On 113 of 149 (75.8%) pig farms, MRSA was present. The prevalence was lower among veal calf (44/173; 25.4%), and dairy (11/181; 6.1%), sheep (7/156; 4.5%), and broiler farms (0/195; 0%). Among 375 persons working/living on the farms, we identified 17 (4.5%) nasal MRSA carriers and all were farmers. All but two isolates from the farms belonged to GG0398 (= CC398). In total, 4529 Dutch retail meat samples were analysed and 412 (9.1%) were MRSA-positive. Poultry meat was most often contaminated. Most meat isolates (97/148; 65.5%) belonged to GG0398. All but one isolate carried mecA, and all were PVL-negative. CONCLUSIONS:Despite the reduction of antimicrobial use by > 70% in veterinary medicine since 2009, most pig farms are still MRSA positive. Farmers have a higher risk of being a nasal MRSA carrier than persons in the general population. Meat is regularly contaminated with MRSA, but this is considered a limited risk for consumers. Almost all the MRSA belonged to GG0398 confirming the continuous predominance of this type of MRSA in livestock and on meat.

ABSTRACT Since March 2022, an increase was observed in multidrug-resistant microorganisms (MDRO), associated with the hospital transfer of Ukrainian patients. The goal was to collect phenotypic susceptibility data and assess clinical implications. Carbapenemase-producing Enterobacterales (CPE, n = 96), Pseudomonas aeruginosa (CPPA, n = 20), and carbapenem-resistant Acinetobacter baumannii–calcoaceticus (CRAB, n = 6) from Ukrainian patients were obtained from March to December 2022 from the Dutch MDRO surveillance. Antimicrobial susceptibility testing was performed using broth microdilution (BMD) when available, fosfomycin agar dilution, disk diffusion (DD) for cefiderocol, and diverse gradient strips. All isolates were sequenced with Illumina next-generation sequencing. For meropenem, aminoglycosides, ceftazidime–avibactam, ceftolozane–tazobactam, and imipenem–relebactam, susceptibility rates were low (0%–30%), due to the high number of bla NDM -positive isolates (79/122; 65%). For cefiderocol, results depended on reading with or without microcolonies, applying EUCAST or CLSI breakpoints, and whether DD or BMD was used; e.g., for Klebsiella pneumoniae , 30%–97% were susceptible. For colistin, 103/111 (93%) non-intrinsically resistant CPE/CPPA/CRAB isolates were susceptible. For most CPE, a low minimal inhibitory concentration (MIC) of <0.5 mg/L was measured for tigecycline and ceftazidime–avibactam–aztreonam. For CPPA, cefiderocol tested susceptible in 65%–100% of isolates. For CRAB, ampicillin–sulbactam MICs were ≥128 mg/L; for sulbactam–durlobactam, 1–2 mg/L. Admission in a Ukrainian hospital in the last year was a risk factor for MDRO, and majority were screening isolates (79%). There is extensive phenotypic resistance to last-resort antibiotics in MDRO from Ukrainian patients. Interpretation of cefiderocol susceptibility results depends on several variables. When treating patients recently admitted in Ukraine, suspected for Gram-negative bacterial infection, this should be taken into consideration. IMPORTANCE Since March 2022, multidrug-resistant microorganisms associated with Ukrainian patients have been detected in national surveillance systems of several European countries. We studied the phenotypic antimicrobial susceptibility to last-resort antibiotics of multidrug-resistant microorganisms from Ukrainian patients in the Netherlands and assessed clinical implications. Our research revealed that there was extensive phenotypic resistance to last-resort antibiotics. Healthcare professionals should be aware of multidrug-resistant microorganisms when treating patients recently admitted in Ukraine, suspected for Gram-negative bacterial infection.

BackgroundThe war in Ukraine led to migration of Ukrainian people. Early 2022, several European national surveillance systems detected multidrug-resistant (MDR) bacteria related to Ukrainian patients.AimTo investigate the genomic epidemiology of New Delhi metallo-β-lactamase (NDM)-producing Providencia stuartii from Ukrainian patients among European countries.MethodsWhole-genome sequencing of 66 isolates sampled in 2022-2023 in 10 European countries enabled whole-genome multilocus sequence typing (wgMLST), identification of resistance genes, replicons, and plasmid reconstructions. Five bla NDM-1-carrying-P. stuartii isolates underwent antimicrobial susceptibility testing (AST). Transferability to Escherichia coli of a bla NDM-1-carrying plasmid from a patient strain was assessed. Epidemiological characteristics of patients with NDM-producing P. stuartii were gathered by questionnaire.ResultswgMLST of the 66 isolates revealed two genetic clusters unrelated to Ukraine and three linked to Ukrainian patients. Of these three, two comprised bla NDM-1-carrying-P. stuartii and the third bla NDM-5-carrying-P. stuartii. The bla NDM-1 clusters (PstCluster-001, n = 22 isolates; PstCluster-002, n = 8 isolates) comprised strains from seven and four countries, respectively. The bla NDM-5 cluster (PstCluster-003) included 13 isolates from six countries. PstCluster-001 and PstCluster-002 isolates carried an MDR plasmid harbouring bla NDM-1, bla OXA-10, bla CMY-16, rmtC and armA, which was transferrable in vitro and, for some Ukrainian patients, shared by other Enterobacterales. AST revealed PstCluster-001 isolates to be extensively drug-resistant (XDR), but susceptible to cefiderocol and aztreonam-avibactam. Patients with data on age (n = 41) were 19-74 years old; of 49 with information on sex, 38 were male.ConclusionXDR P. stuartii were introduced into European countries, requiring increased awareness and precautions when treating patients from conflict-affected areas.

Abstract Background Since March 2022, there has been an emergence of MDR microorganisms (MDRO) in Europe because of an increasing number of Ukrainian patients with MDRO. The goal was to collect large-scale phenotypic susceptibility data to assess implications for clinical practice. Methods For 122 MDRO (carbapenemase-producing Enterobacterales (CPE, n=96), Pseudomonas aeruginosa CPPA (n=20), carbapenem-resistant Acinetobacter baumannii-calcoaceticus (CRAB, n=6), collected from March to December 2022, broth microdilution (BMD), fosfomycin agar dilution, gradient strip ampicillin/sulbactam, sulbactam/durlobactam, ceftazidime-avibactam-aztreonam and disc diffusion (DD) cefiderocol was performed. Epidemiological data was obtained as part of mandatory reporting by Municipal Health Services (CPE), and surveillance questionnaires (CPPA/CRAB). Results Admission at a Ukrainian hospital in the last year was a risk factor for acquiring MDRO. Of all isolates, 65% (79/122) were blaNDM-positive. For meropenem, aminoglycosides, ceftazidime-avibactam, ceftolozane-tazobactam and imipenem-relebactam susceptibility rates were low (0-30%). For cefiderocol, results depended on reading with or without microcolonies, applying EUCAST or CLSI breakpoints, and whether DD or BMD was used: e.g. for Klebsiella pneumoniae, 30%–97% were susceptible, depending on these variables. For colistin, 103/111 (93%) non-intrinsically resistant CPE/CPPA/CRAB isolates were susceptible. For the majority of CPE, a low MIC of <0.5 mg/L was measured for tigecycline and ceftazidime-avibactam-aztreonam. For CPPA, cefiderocol tested susceptible in 65%–100% of isolates. For CRAB, ampicillin/sulbactam MICs were ≥128 mg/L, for sulbactam/durlobactam 1–2 mg/L. Conclusions There is extensive phenotypic resistance to last-resort antibiotics in carbapenemase-producing bacteria from Ukrainian patients. For cefiderocol, interpretation of susceptibility results depends on a number of variables. In case of infection, treatment options are colistin, cefiderocol (CPE/CPPA/CRAB), tigecycline (CPE/CRAB), ceftazidime-avibactam-aztreonam (CPE), sulbactam/durlobactam (CRAB).

BackgroundNew Delhi metallo-beta-lactamase (NDM)-producing Providencia stuartii has been reported from European Union/European Economic Area (EU/EEA) countries with increasing frequency. During 2018 to 2022, 355 cases of NDM-producing P. stuartii were detected in seven hospitals reporting on NDM-production in Enterobacterales in Romania.AimOur aim was to determine the extent of spread of NDM-producing P. stuartii in hospitals in Romania.MethodsWe analysed whole genome sequences and epidemiological data of 74 P. stuartii isolates collected in six hospitals from December 2021 to September 2023.ResultsWe identified four multi-hospital clusters including isolates detected over more than a year, indicating sustained spread of bla NDM-1-carrying P. stuartii within the healthcare system. These clusters consisted of isolates from up to four hospitals and three regions. Three multi-hospital clusters were caused by a specific multidrug-resistant P. stuartii sequence type 46 lineage carrying bla NDM-1 and a large set of additional resistance markers. Investigation in an international context showed that this lineage had already been detected in nine countries (Bulgaria, France, Germany, Ireland, the Netherlands, Romania, Switzerland, United Kingdom, United States) since 2015.ConclusionOur results alert about the risk of carbapenem-resistant P. stuartii transmission in healthcare settings. Enhanced infection prevention and control measures should be instituted as soon as cases are detected in healthcare facilities. National surveillance systems in EU/EEA countries should, in addition to carbapenem-resistant and/or carbapenemase-producing Klebsiella pneumoniae and Escherichia coli, consider reporting carbapenem-resistant and/or carbapenemase-producing P. stuartii and other Enterobacterales where relevant.

Multidrug-resistant organisms (MDRO) pose a significant threat to public health worldwide. The ability to identify antimicrobial resistance determinants, to assess changes in molecular types, and to detect transmission are essential for surveillance and infection prevention of MDRO. Molecular characterization based on long-read sequencing has emerged as a promising alternative to short-read sequencing. The aim of this study was to characterize MDRO for surveillance and transmission studies based on long-read sequencing only. Genomic DNA of 356 MDRO was automatically extracted using the Maxwell-RSC48. The MDRO included 106 Klebsiella pneumoniae isolates, 85 Escherichia coli, 15 Enterobacter cloacae complex, 10 Citrobacter freundii, 34 Pseudomonas aeruginosa, 16 Acinetobacter baumannii, and 69 methicillin-resistant Staphylococcus aureus (MRSA), of which 24 were from an outbreak. MDRO were sequenced using both short-read (Illumina NextSeq 550) and long-read (Nanopore Rapid Barcoding Kit-24-V14, R10.4.1) whole-genome sequencing (WGS). Basecalling was performed for two distinct models using Dorado-0.3.2 duplex mode. Long-read data was assembled using Flye, Canu, Miniasm, Unicycler, Necat, Raven, and Redbean assemblers. Long-read WGS data with > 40 × coverage was used for multi-locus sequence typing (MLST), whole-genome MLST (wgMLST), whole-genome single-nucleotide polymorphisms (wgSNP), in silico multiple locus variable-number of tandem repeat analysis (iMLVA) for MRSA, and identification of resistance genes (ABRicate). Comparison of wgMLST profiles based on long-read and short-read WGS data revealed > 95