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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., Competing Interests: The authors declare no conflict of interest.

During 2015-2022, a genetic cluster of OXA-48-producing uropathogenic Escherichia coli sequence type 127 spread throughout the Netherlands. The 20 isolates we investigated originated mainly from urine, belonged to Clermont phylotype B2, and carried 18 genes encoding putative uropathogenicity factors. The isolates were susceptible to first-choice antimicrobial drugs for urinary tract infections.

Surveillance data shows a geographical overlap between the early coronavirus disease 2019 (COVID-19) pandemic and the past Q fever epidemic (2007-2010) in the Netherlands. We investigated the relationship between past Q fever and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 2020/2021, using a retrospective matched cohort study.In January 2021, former Q fever patients received a questionnaire on demographics, SARS-CoV-2 test results and related hospital/intensive care unit (ICU) admissions. SARS-CoV-2 incidence with 95% confidence intervals (CI) in former Q fever patients and standardised incidence ratios (SIR) to compare to the age-standardised SARS-CoV-2 incidence in the general regional population were calculated.Among 890 former Q fever patients (response rate: 68%), 66 had a PCR-confirmed SARS-CoV-2 infection. Of these, nine (14%) were hospitalised and two (3%) were admitted to ICU. From February to June 2020 the SARS-CoV-2 incidence was 1573/100 000 (95% CI 749-2397) in former Q fever patients and 695/100 000 in the general population (SIR 2.26; 95% CI 1.24-3.80). The incidence was not significantly higher from September 2020 to February 2021.We found no sufficient evidence for a difference in SARS-CoV-2 incidence or an increased severity in former Q fever patients vs. the general population during the period with widespread SARS-CoV-2 testing availability (September 2020-February 2021). This indicates that former Q fever patients do not have a higher risk of SARS-CoV-2 infection.

Background: Colistin is a last-resort treatment option for infections with multidrug-resistant Gram-negative bacteria. However, colistin resistance is increasing., Methods: A six-month prospective matched case-control study was performed in which 22 Dutch laboratories with 32 associated hospitals participated. Laboratories were invited to send a maximum of five colistin-resistant Escherichia coli or Klebsiella pneumoniae (COLR-EK) isolates and five colistin-susceptible isolates (COLS-EK) to the reference laboratory, matched for patient location, material of origin and bacterial species. Epidemiological/clinical data were collected and included in the analysis. Characteristics of COLR-EK/COLS-EK isolates were compared using logistic regression with correction for variables used for matching. Forty-six ColR-EK/ColS-EK pairs were analysed by next-generation sequencing (NGS) for whole-genome multi-locus sequence typing and identification of resistance genes, including mcr genes. To identify chromosomal mutations potentially leading to colistin resistance, NGS reads were mapped against gene sequences of pmrAB, phoPQ, mgrB and crrB ., Results: In total, 72 COLR-EK/COLS-EK pairs (75% E. coli and 25% K. pneumoniae ) were included. Twenty-one percent of COLR-EK patients had received colistin, in contrast to 3% of COLS-EK patients (OR > 2.9). Of COLR-EK isolates, five contained mcr-1 and two mcr-9 . One isolate lost mcr-9 after repeated sub-culturing, but retained colistin resistance. Among 46 sequenced COLR-EK isolates, genetic diversity was large and 19 (41.3%) isolates had chromosomal mutations potentially associated with colistin resistance., Conclusions: Colistin resistance is present but uncommon in the Netherlands and caused by the mcr gene in a minority of COLR-EK isolates. There is a need for surveillance of colistin resistance using appropriate susceptibility testing methods., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2022.)

Background: The Netherlands is currently considered a low endemic country for carbapenem-resistant Enterobacterales (CRE) and carbapenemase-producing Enterobacterales (CPE), experiencing only sporadic hospital outbreaks. This study aims to describe susceptibility to carbapenems and the epidemiology of carbapenemase production in Enterobacterales in the Netherlands in 2017-2019., Methods: Three complementary nationwide surveillance systems are in place to monitor carbapenem susceptibility in the Netherlands. Routine antimicrobial susceptibility test results from medical microbiology laboratories were used to study phenotypic susceptibility of Escherichia coli and Klebsiella pneumoniae. Pathogen surveillance (of all Enterobacterales species) and mandatory notifications were used to describe the characteristics of CPE positive isolates and affected persons., Results: The prevalence of isolates with gradient strip test-confirmed elevated meropenem (> 0.25 mg/L) or imipenem (> 1 mg/L) minimum inhibitory concentration (MIC) in the Netherlands was very low in 2017-2019, with percentages of 0.06% in E. coli and 0.49% in K. pneumoniae, and carbapenem resistances of 0.02% and 0.18%, respectively. A total of 895 unique species/carbapenemase-encoding allele combinations of CPE from 764 persons were submitted between 2017 and 2019, with the annual number of submissions increasing slightly each year. Epidemiological data was available for 660 persons. Screening because of presumed colonisation risk was the reason for sampling in 70.0% (462/660) of persons. Hospitalization abroad was the most common risk factor, being identified in 45.9% of persons., Conclusions: Carbapenem resistance of E. coli and K. pneumoniae remains low in the Netherlands. The annual number of CPE isolates slightly increased during the period 2017-2019. Recent hospitalization abroad is the main risk factor for acquisition of CPE., (© 2022. The Author(s).)

Background: This study aimed to determine short- and long-term physical and psychosocial impact of Coxiella burnetii infection in three distinct entities: Q-fever fatigue syndrome (QFS), chronic Q-fever, and patients with past acute Q-fever without QFS or chronic Q-fever., Methods: Integrative data analysis was performed, combining original data from eight studies measuring quality of life (QoL), fatigue, physical and social functioning with identical validated questionnaires, from three months to eight years after onset infection. Linear trends in each outcome were compared between Q-fever groups using multilevel linear regression analyses to account for repeated measures within patients., Results: Data included 3947 observations of 2313 individual patients (228 QFS, 135 chronic Q-fever and 1950 patients with past acute Q-fever). In the first years following infection, physical and psychosocial impact was highest among QFS patients, and remained high without significant improvements over time. In chronic Q-fever patients, QoL and physical functioning worsened significantly over time. Levels of fatigue and social participation in patients with past acute Q-fever improved significantly over time., Conclusion: The impact differs greatly between the three Q-fever groups. It is important that physicians are aware of these differences, in order to provide relevant care for each patient group., Competing Interests: The authors have declared that no competing interests exist.

Prior regional studies found a high risk of pneumonia for people living close to poultry and goat farms. This epidemiological study in the Netherlands used nationwide antibiotic prescription data as a proxy for pneumonia incidence to investigate whether residents of areas with poultry and goat farms use relatively more antibiotics compared to areas without such farms. We used prescription data on antibiotics most commonly prescribed to treat pneumonia in adults and livestock farming data, both with nationwide coverage. Antibiotic use was expressed as defined daily doses per (4-digit Postal Code (PC4) area)-(age group)-(gender)-(month) combination for the year 2015. We assessed the associations between antibiotic use and farm exposure using negative binomial regression. The amoxicillin, doxycycline, and co-amoxiclav use was significantly higher (5-10% difference in use) in PC4 areas with poultry farms present compared to areas without, even after adjusting for age, gender, smoking, socio-economic status, and goat farm presence. The adjusted models showed no associations between antibiotic use and goat farm presence. The variables included in this study could only partly explain the observed regional differences in antibiotic use. This was an ecological study that precludes inference about causal relations. Further research using individual-level data is recommended.

Verona Integron-encoded Metallo-beta-lactamase (VIM) is the most frequently-encountered carbapenemase in the healthcare-related pathogen Pseudomonas aeruginosa. In the Netherlands, a low-endemic country for antibiotic-resistant bacteria, no national surveillance data on the prevalence of carbapenemase-producing P. aeruginosa (CPPA) was available. Therefore, in 2016, a national surveillance pilot study was initiated to investigate the occurrence, molecular epidemiology, genetic characterization, and resistomes of CPPA among P. aeruginosa isolates submitted by medical microbiology laboratories (MMLs) throughout the country. From 1221 isolates included in the study, 124 (10%) produced carbapenemase (CIM-positive); of these, the majority (95, 77%) were positive for the bla VIM gene using PCR. Sequencing was performed on 112 CIM-positive and 56 CIM-negative isolates (n = 168), and genetic clustering revealed that 75/168 (45%) isolates were highly similar. This genetic cluster, designated Group 1, comprised isolates that belonged to high-risk sequence type ST111/serotype O12, had similar resistomes, and all but two carried the bla VIM-2 allele on an identical class 1 integron. Additionally, Group 1 isolates originated from around the country (i.e. seven provinces) and from multiple MMLs. In conclusion, the Netherlands had experienced a nationwide, inter-institutional, clonal outbreak of VIM-2-producing P. aeruginosa for at least three years, which this pilot study was crucial in identifying. A structured, national surveillance program is strongly advised to monitor the spread of Group 1 CPPA, to identify emerging clones/carbapenemase genes, and to detect transmission in and especially between hospitals in order to control current and future outbreaks., (© 2021. The Author(s).)

Objectives: Evaluation of the extent and appropriateness of antimicrobial use is a cornerstone of antibiotic stewardship programs, but it is time-consuming. Documentation of the indication at the moment of prescription might be more time-efficient. We investigated the real-life feasibility of mandatory documentation of the indication for all hospital antibiotic prescriptions for quality evaluation purposes., Methods: A mandatory prescription-indication format was implemented in the Electronic Medical Record (EMR) of three hospitals using EPIC or ChipSoft HIX software. We evaluated the retrieved data of all antibiotics (J01) prescribed as empiric therapy in adult patients with respiratory tract infections (RTI) or urinary tract infections (UTI), from January through December 2017 in Hospital A, June through October 2019 in Hospital B and May 2019 through June 2020 in Hospital C. Endpoints were the accuracy of the data, defined as agreement between selected indication for the prescription and the documented indication in the EMR, as assessed by manually screening a representative sample of eligible patient records in the EMR of the three hospitals, and appropriateness of the prescriptions, defined as the prescriptions being in accordance with the national guidelines., Results: The datasets of hospitals A, B and C contained 9588, 338 and 5816 empiric antibiotic prescriptions indicated for RTI or UTI, respectively. The selected indication was in accordance with the documented indication in 96.7% (error rate: 10/300), 78.2% (error rate: 53/243), and 86.9% (error rate: 39/298), respectively. A considerable variation in guideline adherence was seen between the hospitals for severe community acquired pneumonia (adherence rate ranged from 35.4 to 53.0%), complicated UTI (40.0-67.1%) and cystitis (5.6-45.3%)., Conclusions: After local validation of the datasets to verify and optimize accuracy of the data, mandatory documentation of the indication for antibiotics enables a reliable and time-efficient method for systematic registration of the extent and appropriateness of empiric antimicrobial use, which might enable benchmarking both in-hospital and between hospitals.

During the first wave of the severe acute respiratory syndrome-coronavirus-2 epidemic in the Netherlands, notifications consisted mostly of patients with relatively severe disease. To enable real-time monitoring of the incidence of mild coronavirus disease 2019 (COVID-19) - for which medical consultation might not be required - the Infectieradar web-based syndromic surveillance system was launched in mid-March 2020. Our aim was to quantify associations between Infectieradar participant characteristics and the incidence of self-reported COVID-19-like illness. Recruitment for this cohort study was via a web announcement. After registering, participants completed weekly questionnaires, reporting the occurrence of a set of symptoms. The incidence rate of COVID-19-like illness was estimated and multivariable Poisson regression used to estimate the relative risks associated with sociodemographic variables, lifestyle factors and pre-existing medical conditions. Between 17 March and 24 May 2020, 25 663 active participants were identified, who reported 7060 episodes of COVID-19-like illness over 131 404 person-weeks of follow-up. The incidence rate declined over the analysis period, consistent with the decline in notified cases. Male sex, age 65+ years and higher education were associated with a significantly lower COVID-19-like illness incidence rate (adjusted rate ratios (RRs) of 0.80 (95% CI 0.76-0.84), 0.77 (0.70-0.85), 0.84 (0.80-0.88), respectively) and the baseline characteristics ever-smoker, asthma, allergies, diabetes, chronic lung disease, cardiovascular disease and children in the household were associated with a higher incidence (RRs of 1.11 (1.04-1.19) to 1.69 (1.50-1.90)). Web-based syndromic surveillance has proven useful for monitoring the temporal trends in, and risk factors associated with, the incidence of mild disease. Increased relative risks observed for several patient factors could reflect a combination of exposure risk, susceptibility to infection and propensity to report symptoms.

Objectives: Long-term care facilities (LTCFs) may act as a reservoir of ESBL-producing Enterobacterales (ESBL-E) and carbapenemase-producing Enterobacterales (CPE) for hospitals and the general population. In this study, we estimated the prevalence and molecular epidemiology of rectal carriage with ESBL-E and CPE in residents of Dutch LTCFs between March 2018 and December 2018., Methods: LTCFs were geographically selected across the country. For each LTCF, a random sample of residents were tested for ESBL-E and CPE in 2018. To identify risk factors for high carriage prevalence and/or individual carriage, characteristics of LTCFs and of a subset of the tested residents were collected. WGS was conducted on isolates from LTCFs with an ESBL-E prevalence of >10% and all CPE isolates to identify institutional clonal transmission., Results: A total of 4420 residents of 159 LTCFs were included. The weighted mean ESBL-E prevalence was 8.3% (95% CI: 6.8-10.0) and no CPE were found. In 53 LTCFs (33%), where ESBL-E prevalence was >10%, MLST using WGS (wgMLST) was performed. This included 264 isolates, the majority being Escherichia coli (n = 224) followed by Klebsiella pneumoniae (n = 30). Genetic clusters were identified in more than half (30/53; 57%) of high ESBL-positive LTCFs. Among the E. coli isolates, blaCTX-M-15 (92/224; 41%) and blaCTX-M-27 (40/224; 18%) were the most prevalent ESBL-encoding genes. For K. pneumoniae isolates, the most common was blaCTX-M-15 (23/30; 80%)., Conclusions: The estimated prevalence of ESBL-E rectal carriage in Dutch LTCFs is 8.3% and resistance is observed mainly in E. coli with predominance of blaCTX-M-15 and blaCTX-M-27. ESBL-E prevalence in LTCFs seems comparable to previously reported prevalence in hospitals and the general population., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Carbapenemases produced by Enterobacterales are often encoded by genes on transferable plasmids and represent a major healthcare problem, especially if the plasmids contain additional antibiotic resistance genes. As part of Dutch national surveillance, 50 medical microbiological laboratories submit their Enterobacterales isolates suspected of carbapenemase production to the National Institute for Public Health and the Environment for characterization. All isolates for which carbapenemase production is confirmed are subjected to next-generation sequencing., Objectives: To study the molecular characteristics of a genetic cluster of Enterobacter cloacae complex isolates collected in Dutch national surveillance in the period 2015-20 in the Netherlands., Methods: Short- and long-read genome sequencing was used in combination with MLST and pan-genome MLST (pgMLST) analyses. Automated antimicrobial susceptibility testing (AST), the Etest for meropenem and the broth microdilution test for colistin were performed. The carbapenem inactivation method was used to assess carbapenemase production., Results: pgMLST revealed that nine E. cloacae complex isolates from three different hospitals in the Netherlands differed by <20 alleles and grouped in a genetic cluster termed EclCluster-013. Seven isolates were submitted by one hospital in 2016-20. EclCluster-013 isolates produced carbapenemase and were from ST78, a globally disseminated lineage. EclCluster-013 isolates harboured a 316 078 bp IncH12 plasmid carrying the bla VIM-1 carbapenemase and the novel mcr-9 colistin resistance gene along with genes encoding resistance to different antibiotic classes. AST showed that EclCluster-013 isolates were MDR, but susceptible to meropenem (<2 mg/L) and colistin (<2 mg/L)., Conclusions: The EclCluster-013 reported here represents an MDR E. cloacae complex ST78 strain containing an IncH12 plasmid carrying both the bla VIM-1 carbapenemase and the mcr-9 colistin resistance gene., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.)

Infections due to extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are often preceded by asymptomatic carriage. Higher incidences in enteric infectious diseases during summer have been reported. Here, we assessed whether the presence of seasonality in intestinal ESBL-Escherichia coli/Klebsiella pneumoniae (ESBL-E/K) carriage in the general Dutch population exists. From 2014 to 2017, the faecal carriage of ESBL-E/K in healthy individuals was determined in three cross-sectional studies in the Netherlands, including 5985 subjects. Results were pooled to identify seasonal trends in prevalence (by month of sampling). Multivariate logistic regression analysis was used to calculate pooled odds ratios and 95% confidence intervals. Results were adjusted for age, sex, antibiotic use and travel. Overall prevalence of ESBL-E/K carriage was 4.3% (n = 260 ESBL-E/K-positive), with differences between months ranging from 2.6% to 7.4%. Compared to January, the monthly prevalence of ESBL-E carriage was highest in August (OR 1.88, 95% CI 1.02-3.49) and September (OR 2.25, 95% CI 1.30-3.89). The observed monthly differences in ESBL-E/K carriage rates suggest that there is seasonal variation in exposure to ESBL-E/K other than due to travelling and antibiotic use. This should be taken into account in designing future ESBL-E prevalence studies in temperate regions.

Background: Studies on various Gram-negative bacteria suggest that resistance to carbapenem antibiotics is responsible for increased mortality in patients; however, results are not conclusive. We first assessed the 28-day in-hospital all-cause mortality in patients with Verona Integron-encoded Metallo-β-lactamase-positive Pseudomonas aeruginosa (VIM-PA) bacteremia compared to patients with VIM-negative, carbapenem-susceptible P. aeruginosa (CS-PA) bacteremia. Second, we identified determinants for mortality and survival., Methods: All patients with a positive blood culture with VIM-PA or CS-PA between January 2004 and January 2016 were included. Kaplan-Meier survival curves were constructed, and survivors and non-survivors were compared on relevant clinical parameters using univariate analyses, and multivariable analyses using a Cox-proportional hazard model., Results: In total, 249 patients were included, of which 58 (23.3%) died. Seventeen out of 40 (42.5%) patients with VIM-PA died, compared to 41 out of 209 (19.6%) patients with CS-PA (difference = 22.9%, P-value = 0.001). Assumed acquisition of the bacterium at the intensive care unit was significantly associated with mortality (HR = 3.32, 95%CI = 1.60-6.87), and having had adequate antibiotic therapy in days 1-14 after the positive blood culture was identified as a determinant for survival (HR = 0.03, 95%CI = 0.01-0.06). VIM-PA vs CS-PA was not identified as an independent risk factor for mortality., Conclusions: The crude mortality rate was significantly higher in patients with a VIM-PA bacteremia compared to patients with a CS-PA bacteremia; however, when analyzing the data in a multivariable model this difference was non-significant. Awareness of the presence of P. aeruginosa in the hospital environment that may be transmitted to patients and rapid microbiological diagnostics are essential for timely administration of appropriate antibiotics. Acquisition of P. aeruginosa should be prevented, independent of resistance profile.

In the aftermath of a large Q fever (QF) epidemic in the Netherlands during 2007-2010, new chronic QF (CQF) patients continue to be detected. We developed a health-economic decision model to evaluate the cost-effectiveness of a 1-time screening program for CQF 7 years after the epidemic. The model was parameterized with spatial data on QF notifications for the Netherlands, prevalence data from targeted screening studies, and clinical data from the national QF database. The cost-effectiveness of screening varied substantially among subpopulations and geographic areas. Screening that focused on cardiovascular risk patients in areas with high QF incidence during the epidemic ranged from cost-saving to €31,373 per quality-adjusted life year gained, depending on the method to estimate the prevalence of CQF. The cost per quality-adjusted life year of mass screening of all older adults was €70,000 in the most optimistic scenario.

From 2007 to 2010, the largest reported Q-fever epidemic occurred in the Netherlands with 4026 notified laboratory-confirmed cases. During the course of the epidemic, health-seeking behaviour changed and awareness among health professionals increased. Changes in laboratory workflows were implemented. The aim of this study was to analyse how these changes instigated adjustments of notification criteria and how these adjustments affected the monitoring and interpretation of the epidemic. We used the articles on laboratory procedures related to the epidemic and a description of the changes that were made to the notification criteria. We compared the output of a regional laboratory with notifications to the regional Public Health Service and the national register of infectious diseases. We compared the international notification criteria for acute Q-fever. Screening with ELISA IgM phase II and PCR was added to the diagnostic workflow. In the course of the epidemic, serology often revealed a positive IgG/IgM result although cases were not infected recently. With increasing background seroprevalence, the presence of IgM antibodies can only be suggestive for acute Q-fever and has to be confirmed either by seroconversion of IgG or a positive PCR result. Differences in sero-epidemiology make it unlikely that full harmonisation of notification criteria between countries is feasible.

Background: Echocardiographic screening of acute Q-fever patients and antibiotic prophylaxis for patients with cardiac valvulopathy is considered an important approach to prevent chronic Q-fever-related endocarditis. During a large Q-fever epidemic in the Netherlands, routine screening echocardiography was discontinued, raising controversy in the international literature. We followed a cohort of acute Q-fever patients to estimate the risk for developing chronic Q-fever, and we evaluated the impact of screening in patients who were not yet known to have a valvulopathy., Methods: The study population consisted of patients diagnosed with acute Q-fever in 2007 and 2008. We retrospectively reviewed all screening echocardiographs and checked for development of chronic Q-fever 8 years after the acute episode. Risks of developing chronic Q-fever in relation to the presence or absence of valvulopathy were analyzed with logistic regression., Results: The cohort included 509 patients, of whom 306 received echocardiographic screening. There was no significant difference (P-value = .22) in occurrence of chronic Q-fever between patients with a newly detected valvulopathy (2/84, 2.4%) and those with no valvulopathy (12/202, 5.9%). Two patients with a newly detected valvulopathy, who did not receive antibiotic prophylaxis, developed chronic Q-fever at a later stage., Conclusions: We found no difference in outcome between patients with and without a valvulopathy newly detected by echocardiographic screening. In retrospect, the 2 above-mentioned patients could have benefitted from antibiotic prophylaxis, but its omission must be weighed against the unnecessary large-scale and long-term use of antibiotics that would have resulted from universal echocardiographic screening.

[This corrects the article DOI: 10.1371/journal.pone.0193834.].

Background: This longitudinal study aimed to investigate (risk factors for) persistence of carriage and molecular characteristics of extended-spectrum and plasmid-encoded AmpC β-lactamase-producing (ESBL/pAmpC) Escherichia coli and Klebsiella pneumoniae (ESBL-E/K) in adults in the Dutch community., Methods: Following a cross-sectional study (ESBL-E/K prevalence, 4.5%), a subset of ESBL-E/K-positive (n = 76) and -negative (n = 249) individuals volunteered to provide 5 monthly fecal samples and questionnaires. ESBL-E/K was cultured using selective enrichment/culture, and multilocus sequence types (MLSTs) were determined. ESBL/pAmpC-genes were analyzed using polymerase chain reaction (PCR) and sequencing. Plasmids were characterized and subtyped by plasmid MLST. Risk factors for persistent carriage were analyzed using logistic regression., Results: Of the initially ESBL-E/K-positive participants, 25 of 76 (32.9%) remained positive in all subsequent samples; 51 of 76 persons (67.1%) tested ESBL-E/K negative at some time point during follow-up, of which 31 (40.8%) stayed negative throughout the longitudinal study. Carriers often carried the same ESBL gene and plasmid, but sometimes in different ESBL-E/K strains, indicative for horizontal transfer of plasmids. Of the 249 initially ESBL-E/K-negative participants, the majority (n = 218 [87.6%]) tested negative during 8 months of follow-up, whereas 31 of 249 (12.4%) participants acquired an ESBL-E/K. Escherichia coli phylogenetic group B2 and D and travel to ESBL high-prevalence countries were associated with prolonged carriage., Conclusions: ESBL-E/K carriage persisted for >8 months in 32.9% of the initially ESBL-positive individuals, while 12.4% of initially negative individuals acquired ESBL-E/K during the study. A single positive test result provides no accurate prediction for prolonged carriage. Acquisition/loss of ESBL-E/K does not seem to be a random process, but differs between bacterial genotypes.

A subset of the study population from a cross-sectional study of carriership of ESBL/pAmpC-producing E. coli (ESBL-E) in the general population was followed up by five successive samples over an approximate half year period, leading to six samples in 333 persons. Fecal samples were cultured and analyzed for the presence of E. coli types as characterized by MLST, and ESBL/pAmpC genes were analysed by PCR and sequencing. The study included 255 persons who had a negative first sample, to allow observations of acquiring carriership of ESBL-E. Any individual record thus consisted of a series of snapshots of episodes of presence and absence of ESBL-E carriage. A survival model was built to estimate times to acquire or lose carriership, allowing for any combination of ESBL/pAmpC gene and E. coli MLST type. In carriers, the mean time to lose carriership was 1.1 (95% range 0.8-1.6) years. The estimated mean time to acquire carriership was 3.0 (95% range 1.6-6.3) years. Analysis of these times by ESBL/pAmpC gene found substantial variation among resistance genes both in persistence of carriership and in rates of acquiring carriership: blaCTX-M-1, blaCTX-M-14, blaCTX-M-15, blaCTX-M-27 and blaSHV-12 were easily acquired, but blaCTX-M-1 and blaSHV-12 were also easily lost, while blaCTX-M-15, blaCTX-M-27 and blaCMY-2 were more likely to persist. When in addition bacterial host types were included, some combinations appeared more persistent than others (blaCTX-M-1 in ST10 and ST58; blaCTX-M-14, blaCMY-2, and blaSHV-12 in ST69), or were acquired with higher frequency (blaCTX-M-14 in ST38, ST69, and ST131; blaCTX-M-15 and blaCTX-M-27 in ST131; blaSHV-12 in ST69). The relatively short duration of carriership means that when an intervention drastically reduces the exposure of humans to ESBL-E, the prevalence will be halved in 0.66 years. The observed differences between carriage rates of ESBL/pAmpC genes and E. coli strains need further investigation.

A cross-sectional study was performed among 2494 adults not living or working on a farm to assess prevalence of Clostridium difficile (CD) colonization and risk factors in a livestock dense area. CD prevalence was 1·2%. Twenty-one persons were colonized with a toxigenic strain and nine with a non-toxigenic strain. CD-positive persons did not live closer to livestock farms than individuals negative for CD. Antibiotic exposure in the preceding 3 months was a risk factor for CD colonization (odds ratio 3·70; 95% confidence interval 1·25-10·95).

Objectives: In the Netherlands there is an ongoing debate regarding environmental health risks of livestock farming for neighbouring residents. This explorative study aims to determine the prevalence of carriage of extended-spectrum β-lactamase and/or plasmid-mediated AmpC-producing Enterobacteriaceae (ESBL/pAmpC-E) in the general population living in a livestock-dense area, and to study associations between determinants, including exposure through contact with animals and the environment, and human carriage of ESBL/pAmpC-E., Methods: A cross-sectional study was performed among 2432 adults (aged 20-72 years) in 12 temporary research centres in the south of the Netherlands, consisting of a questionnaire and analysis of a faecal sample to assess carriage of ESBL/pAmpC-E. Risk factors were analysed using logistic regression., Results: The prevalence for carriage of ESBL/pAmpC-E was 4.5% (109/2432; 95% CI 3.7-5.4) ranging from 1.4% to 10.9% among the research centres. ESBL/pAmpC resistance genes were detected in Escherichia coli and Klebsiella pneumoniae isolates obtained from these 109 persons and the most common ESBL-resistance genes were bla CTX-M-15 , bla CTX-M-14/17 and bla CTX-M-1 , originating from 76 participants. Travel in the previous 12 months to Africa, Asia or Latin America (OR 2.82; 95% CI 1.71-4.63), having kept cows for a hobby in the previous 5 years (OR 3.77; 95% CI 1.22-11.64), usage of proton-pump inhibitors (OR 1.84; 95% CI 1.05-3.23), and living within 1000 m of a mink farm (OR 2.26; 95% CI 1.28-3.98) were identified as risk factors. Exposure to poultry was not identified as a risk factor., Conclusions: Overall, living in close proximity to livestock animals and farms does not seem to be a risk factor for carriage of ESBL/pAmpC-E., (Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)