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

We describe a community outbreak of Panton-Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus (MRSA) during November 2023-June 2024 in the Netherlands. We identified a massage center as the source. Case-patients experienced skin infections and abscesses. This study highlights the importance of genomic surveillance of MRSA in distinguishing Panton-Valentine leukocidin-positive MRSA.

Importance:Household contacts of patients with invasive group A streptococcus (iGAS) disease have an increased risk of iGAS. In the Netherlands, the iGAS public health policy was changed in January 2023, offering antibiotic prophylaxis to household contacts of all patients with iGAS rather than only those presenting with necrotizing fasciitis or streptococcal toxic shock syndrome. Objective:To estimate risk of iGAS in the general population and among household and other contacts of primary patients with iGAS, before and after the policy change. Design, Setting, and Participants:This nationwide, population-based, open cohort study, linked population registry data with iGAS laboratory data for the study period (April 2022 to December 2024). The study population consisted of all persons included in the Dutch population registry at any time during the study period. The case definition was an iGAS isolate submitted to the Netherlands Reference Laboratory for Bacterial Meningitis, with disease onset in the study period. Exposure:For contacts of primary patients with iGAS, exposure risk period was defined as the 30 days after culture date of the index patient. Exposure under the new policy was defined as all person-time after January 20, 2023. Main Outcomes and Measures:Incidence rate ratios (IRR) of iGAS during the 30-day risk period compared with unexposed person-time were estimated. Secondary attack rates among household contacts were estimated with an odds ratio (OR) to compare attack rates before and after the policy change. Estimates were adjusted for age group, sex, household socioeconomic status, and year quarter. Results:A total of 19 006 247 persons (9 467 251 male [49.8%]; 6 308 794 [33.2%] aged 20-45 years) contributed 51 067 977 person-years to the analysis. A total of 3644 iGAS isolates from 3630 unique persons were included, of which 14 were household secondary cases. The IRR for household contacts during the risk period was 235.25 (95% CI, 94.35-586.59) before and 74.00 (95% CI, 35.17-155.71) after the policy change, compared with unexposed person-time. The secondary attack rate among household contacts was 0.219% (7 individuals) before and 0.047% (7 individuals) after the policy change (adjusted OR, 0.17; 95% CI, 0.03-0.83). Conclusions and Relevance:In this nationwide cohort study, there was a reduction in secondary iGAS risk among household contacts after implementation of an expanded antibiotic prophylaxis policy, which suggests that antibiotic prophylaxis for household contacts of patients with iGAS prevents secondary iGAS infection.

Human granulocytic anaplasmosis (HGA) is caused by Anaplasma phagocytophilum. In the Netherlands, the bacterium is present in a few percent of Ixodes ricinus ticks, but only a specific subvariant is associated with human disease. Although the infection is often asymptomatic, the clinical course can be severe and unpredictable. Here, we describe three recent Dutch cases: two autochthonous cases with a severe course and one case acquired in the United States. All patients recovered rapidly after initiation of doxycycline following the final diagnosis. Awareness of tick-borne diseases other than Lyme disease is important for healthcare professionals in primary, secondary, and tertiary care, as well as for supporting (laboratory) specialties such as clinical chemistry and medical microbiology.

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.

OBJECTIVE:To provide insight into the point prevalence of bacteriuria in frail older adults residing in Dutch nursing homes (NHs), to describe identified bacteria, and to investigate possible associations between resident characteristics and asymptomatic bacteriuria (ASB). DESIGN:Cross-sectional study. SETTING AND PARTICIPANTS:NH residents residing in long-term care wards in 22 Dutch NHs between February 2024 and July 2024. METHODS:Urine samples were collected from NH residents (either through spontaneous voiding, extracted from urine-saturated incontinence material, or from an indwelling urinary catheter) and cultured. Resident characteristics and clinical data, including urinary tract infection (UTI)-related signs and symptoms, were collected via NH staff and from electronic health records. Primary outcome is bacteriuria (>105 colony-forming units per milliliter) point prevalence, and secondary outcomes are types of identified bacteria. Resident characteristics associated with ASB were explored using logistic mixed-model analysis. RESULTS:Urine samples from 570 residents were analyzed (56.8% spontaneously voided; 27.7% extracted from incontinence material; 15.4% from an indwelling urinary catheter). Bacteriuria was found in 54.2% of the samples (women: 58.8%; men: 45.0%); only one resident had UTI-related signs and symptoms. Bacteriuria prevalence was 40.4% in spontaneously voided urine samples, 67.7% in samples extracted from incontinence material, and 80.7% in samples collected from an indwelling urinary catheter. The most commonly identified bacteria were Escherichia coli (39.9%). Female gender was positively associated with ASB [odds ratio (OR) 2.50, 95% CI 1.41-4.44], whereas dementia was inversely associated (OR 0.55, 95% CI 0.34-0.89). CONCLUSION AND IMPLICATIONS:The ASB rates identified in our study are comparable to previous findings. More research is needed to provide insight into the identified association between dementia and ASB.

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.

Objectives:Recently, several MRSA community outbreaks occurred in the Netherlands, including one caused by an impetigo-causing MRSA strain resistant to fusidic acid. Since fusidic acid and flucloxacillin are the main treatment options for impetigo, increasing resistance limits treatment possibilities. We examined trends in fusidic acid resistance percentages among MRSA isolates in the Netherlands. Materials and methods:Data on routine bacteriological cultures between 2016 and 2023 from 30 laboratories were extracted from the national surveillance system on antimicrobial resistance (ISIS-AR). Fusidic acid resistance percentages per year were calculated both overall and per age group for all MRSA isolates, and more specific, for the subset of MRSA isolates from wound/pus/skin samples collected by general practitioners (WPS-GP). Trends were determined using logistic regression and compared with trends among MSSA isolates. Results:We found an increase in fusidic acid resistance among MRSA isolates from 15% (2016) to 29% (2023) (P < 0.001), which differed significantly (P < 0.001) from the trend among MSSA isolates (10%-12%). An increase was also found in MRSA WPS-GP isolates, both among young children and the population of 13-64 years old, but not among elderly. The trends remained significant after exclusion of isolates associated with known fusidic acid-resistant MRSA outbreaks, both among MRSA isolates overall (OR = 1.10, 95% CI: 1.07-1.14, P < 0.001) and among MRSA WPS-GP isolates (OR = 1.14, 1.07-1.21, P < 0.001). Conclusions:In conclusion, an increasing trend in fusidic acid resistance was found among MRSA isolates. Since impaired treatment for impetigo might ease the spread of (fusidic acid-resistant) MRSA, extra vigilance is warranted.

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.

OBJECTIVES:Cefiderocol is a novel last-resort cephalosporin antimicrobial increasingly used for difficult-to-treat infections by multidrug-resistant microorganisms, and is effective against carbapenem-resistant Enterobacterales and Pseudomonas species. Multiple chromosomally encoded genetic determinants have been implicated in cefiderocol resistance, including mutations, deletions and/or frameshifts. However, identification of these determinants remains labour-intensive and time-consuming. Therefore, we share CefiderocolFinder, a bioinformatics pipeline to detect 25 genetic adaptations implicated in cefiderocol resistance from short-read whole-genome sequencing (WGS) data. METHODS:CefiderocolFinder was built using Python, supports WGS data of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii, and contains alignment, variant calling, annotation and filtering steps. A short-read WGS dataset (n = 98) and a validation WGS dataset (n = 21) with cefiderocol antimicrobial susceptibility testing (AST) results were used to interpret and validate CefiderocolFinder. RESULTS:Using CefiderocolFinder, with WGS data from 98 multidrug-resistant microorganisms collected from Ukrainian patients in 2022, six unique genetic adaptations were detected. These adaptations were associated with higher MICs in AST with cefiderocol. Loss-of-function mutations were found in the siderophore receptor cirA, the general porins oprD, ompC, ompF, negative regulator of the acrAB-tolC efflux operon acrR and a conservative in-frame insertion YRIN in ftsI encoding for penicillin-binding protein 3. The adaptations were identified in 12 of 16 E. coli (75%), 1 of 60 K. pneumoniae (1%), 6 of 17 P. aeruginosa (35%) and 0 of 5 A. baumannii (0%) isolates. CefiderocolFinder was validated using publicly available datasets. CONCLUSIONS:CefiderocolFinder provides context to corroborate phenotypical AST from WGS data, especially when the result is in an area of technical uncertainty. For E. coli, CefiderocolFinder can be a valuable tool for informing the clinician of specific genetic adaptations associated with resistance to cefiderocol, where for K. pneumoniae and P. aeruginosa the prediction of phenotypical resistance can be improved. CefiderocolFinder is available open access at http://github.com/Bryan-vd-Brand/CefiderocolFinder.

We describe the genetic characteristics of a fusidic acid- and meticillin-resistant Staphylococcus aureus (MRSA) clone widespread in Europe, based on whole genome sequences from 317 isolates. The clone is causing impetigo and other skin and soft tissue infections, primarily in young children. Comparison with publicly available S. aureus ST121 sequences showed that the clone is clearly distinct from previously described ST121 clones. European and other international readers should be aware of the emergence of this community-acquired MRSA clone.

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.

Introduction. Genes encoding OXA-48-like carbapenem-hydrolyzing enzymes are often located on plasmids and are abundant among carbapenemase-producing Enterobacterales (CPE) worldwide. After a large bla OXA-48 plasmid-mediated outbreak in 2011, routine screening of patients at risk of CPE carriage on admission and every 7 days during hospitalization was implemented in a large hospital in the Netherlands. The objective of this study was to investigate the dynamics of the hospitals’ 2011 outbreak-associated bla OXA-48 plasmid among CPE collected from 2011 to 2021. Methods. A selection of 86 bla OXA-48-carrying CPE isolates was made from 374 isolates collected over an 11-year study period. Species included Escherichia coli (Eco), Klebsiella pneumoniae (Kpn), Enterobacter cloacae complex (Ecl), Citrobacter freundii (Cfr), Citrobacter koseri (Cko) and Morganella morgani (Mmo). Short-read sequencing was combined with long-read sequencing for all isolates to reconstruct bla OXA-48-like plasmids and chromosomes of CPE. MASH, MOBsuite, ResFinder, PlasmidFinder and SNP analyses were performed to study diversity. pOXA-48 plasmids were compared to plasmid sequences that were sequenced for the Dutch CPE surveillance in the same time period. Results. In total for the 86 CPE, 2 failed genomic assemblies and 78 bla OXA-48-encoding plasmids were reconstructed, and six bla OXA-48 genes were located chromosomally. The 2011 outbreak-associated bla OXA-48 plasmid of 63.6 kb with IncL replicon was found in Cfr, Ecl, Eco, Kpn and Mmo and primarily between 2011 and 2014 and indicated as LR025105 as MASH nearest neighbour. From 2014 onwards, 11 other types of bla OXA-48-carrying plasmids with different antibiotic-resistant genes and replicons were discovered, representing the earlier defined distinct pOXA-48 plasmid groups found in the Netherlands. Furthermore, on a national level, the LR025105 plasmid was found after 2015 in many different bacterial backgrounds, highlighting the promiscuous nature of this pOXA-48 plasmid. Conclusion. After a large bla OXA-48 outbreak in a large hospital in the Netherlands, the composition of the bla OXA-48 plasmid population in this hospital diversified over time and is in line with national surveillance data. Plasmid sequencing provided valuable insight into the transmission dynamics of bla OXA-48-encoding plasmids and showed no indication of the persistence of the 2011 bla OXA-48 plasmid in the hospital environment.

End 2023, the UK Health Security Agency sent an alert about a new hypervirulent Clostridioides difficile PCR ribotype, ribotype 955 (RT955), causing slowly progressing infection clusters in hospitals in the Midlands. Between March 2018 and February 2022, surveillance of Clostridioides difficile infections (CDI) was performed in southern Serbia with centres providing medical services for approximately 750,000 inhabitants. Using the ECDC recommended protocol, clinical, epidemiological and microbiological data were collected. C. difficile RT955 was identified in 27 (7%) of 383 surveyed patients with CDI. Of 27 patients, 16 (59%) was older than 60 years and 19 (70%) were male. CDI was always associated with previous antibiotic therapy and had a hospital onset in 23 (85%) patients. The clinical presentation was milder than reported in UK. All sequenced strains belonged to multilocus sequence type (ST) 1 and were highly similar, with 0-1 alleles differences in a core genome multilocus sequence typing analysis. The strains differed clearly from the UK RT955 outbreak strain by whole genome sequencing and phenotypic susceptibility to metronidazole, lincosamides and rifampicin. Interestingly, a high-level erythromycin resistance was observed associated with the presence of the mrmA gene. Both the UK and Serbian RT955 strains contained gyrA_p.T82I associated with resistance to fluoroquinolone antimicrobials and carried the PnimBG promoter mutation, suggestive for haem-dependent metronidazole resistance. We conclude that C. difficile RT955 is present in southern Serbia since 2018. The Serbian RT955 strains differed clearly from a representative UK cluster strain.

Background The incidence of leptospirosis, a zoonotic infection transmitted mainly by rodents, has increased in humans over the past decade in the Netherlands. Previous studies, mostly from countries with tropical climates, suggest that temperature and rainfall influence leptospirosis incidence. Aim We aimed to identify factors that could explain the increasing leptospirosis incidence in the Netherlands, including temperature and precipitation. Methods Epidemiological data of leptospirosis cases notified from 2005 to 2023 to the national surveillance system were analysed to identify changes over the years. Negative binomial regression models were used to assess associations between weather variables and leptospirosis incidence. Results From 2005 to 2023, 1,164 cases were notified. The annual number of cases increased 2.7-fold in the period of 2019–2023 compared with 2005–2009, and the number of autochthonous cases 4.1-fold. Data from 1,158 cases were included in the analyses, and 596 (51.5%) of these cases were autochthonous. Most cases were male (n = 927; 80.1%), needed hospital treatment (n = 861; 74.4%) and acquired the infection through contact with surface water and/or soil (n = 611, 72.6%). Higher mean winter (incidence rate ratio (IRR) = 1.27; 95% confidence interval (CI): 1.18–1.36) and summer (IRR = 1.38; 95% CI: 1.18–1.61) temperatures were significantly associated with increased leptospirosis incidence. Conclusion Leptospirosis incidence has increased over the past decades and may continue to increase due to climate change. Prevention should aim at advising the appropriate preventive measures to avoid exposure to Leptospira and increasing awareness about leptospirosis among clinicians to allow for timely diagnosis and treatment.

BACKGROUND:Vancomycin-resistant Enterococcus faecium (VREfm) is an opportunistic pathogen, which can cause outbreaks in hospitals. In the Netherlands, several national guidelines and guidance documents on different aspects of VREfm management are available. Most available guidelines are written towards the hospital setting and only few on long-term care facilities (LTCFs). Moreover, not all aspects of VREfm management are covered, recommendations differ and the level of compliance to these guidelines is unknown. The aim of this study was to get insight into the routine VREfm policies in Dutch healthcare facilities with regard to screening, diagnostics and infection control measures. METHODS:Online questionnaires were sent to representatives of Dutch hospitals and LTCFs. The questionnaire included questions regarding the definition of VRE, screening, diagnostics, patient isolation, cleaning procedures, VREfm clearance and VREfm outbreaks. FINDINGS:The questionnaire was completed by 61 hospitals with a response rate of 84.1% and 57 LTCFs, mostly nursing homes. Most hospitals reported VREfm outbreaks in the previous decade, whereas only one LTCF reported an outbreak. Of the hospitals, 87% perform VREfm screening versus 50% of the LTCFs. VREfm-positive patients are isolated in 98% of hospitals and 83% of LTCFs. Protocols regarding how to unlabel VREfm-positive patients are in place in 84% of the hospitals and in 51% of LTCFs. The details of these measures differ substantially between healthcare facilities. CONCLUSION:This study has shown that most hospitals and some LTCFs in the Netherlands have standard procedures for VREfm management to some level, although the comprehensiveness and details of the measures differ per hospital. More uniform policies would improve comparability of VREfm data on a regional/national level.

Meticillineresistente Staphylococcus aureus (MRSA) zou vooral een zieken­huisbacterie zijn, maar wordt ook geregeld buiten het ziekenhuis opgelopen (community-acquired (CA-)MRSA). In de afgelopen jaren vonden er meerdere aanzienlijke MRSA-uitbraken plaats in de samenleving. Een infectie met CA-MRSA kan ernstig verlopen, met onder andere abcesvorming of necrotiserende pneumonie. S. aureus blijkt geregeld resistent tegen fusidinezuur, de eerstekeusbehandeling bij impetigo, en inadequate behandeling leidt tot verdere verspreiding van MRSA. Huisartsen kunnen helpen om MRSA-uitbraken te signaleren en af te remmen.