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Background In the last decade, veterinary antimicrobial usage (AMU) and antimicrobial resistance (AMR) among indicator bacteria in livestock have decreased substantially in the Netherlands. The extent to which this decrease has affected AMR levels among human infections remains unclear. Objectives To assess the association between AMU in livestock and AMR in Escherichia coli isolates from human urinary tract infections (UTIs). Methods Data on AMR and AMU between 2009 and 2020 from Dutch national surveillance programmes for humans and livestock were used. Associations between AMU in four major livestock sectors and AMR in humans were assessed for 10 antimicrobial classes and the ESBL resistance profile, using logistic regression analysis. Associations between AMU and AMR in livestock, between AMR in livestock and in humans, and between AMU and AMR in humans were also assessed. Results Statistical significance was reached for 16/31 of the tested associations between AMU in livestock and AMR in human E. coli UTIs. Of the significant associations, 11 were positive (OR 1.01–1.24), whereas 5 were negative (OR 0.96–0.99). All associations between human AMU and AMR in E. coli isolates from UTIs were positive and statistically significant. Weak but significant positive correlations were also observed between livestock AMR and human AMR. Conclusions Although several significant associations between AMU in livestock and AMR in human UTIs caused by E. coli were observed, the associations between AMU and AMR were generally stronger within the human and animal populations. This indicates that potential zoonotic spread of AMR in E. coli causing human UTIs from livestock sources is limited. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovar Heidelberg is among the most prevalent causes of human salmonellosis in the United States and Canada but has been reported infrequently in Europe (1-3). Although most nontyphoidal [...]

Background: Gastric acid-suppressive therapy has been suggested to increase the risk for intestinal carriage of MDR Enterobacterales, but there is scarce community-based evidence substantiating this risk.Objectives: To investigate if acid-suppressant use is associated with a risk of intestinal carriage of ESBL and carbapenemase-producing Enterobacterales (ESBL-E) in the open population, and to assess possible modifying factors.Methods: Within the framework of a nationwide seroprevalence study, we identified a population-based cross-sectional cohort comprising 2746 adults (≥18 years), who provided stool specimens between February 2016 and June 2017. Specimens were tested by phenotypic assays and confirmatory genotype analysis to detect carriage of ESBL-E. Covariate data were extracted from self-administered questionnaires. ORs and 95% CIs were estimated using multivariable multilevel logistic regression, controlling for confounders informed by directed acyclic graphs.Results: Among 2746 participants, 316 (11.5%) used acid suppressants; the prevalence of ESBL-E carriage was 7.4% (95% CI, 6.1%-8.6%). Current use of acid suppressants was not associated with ESBL-E carriage (adjusted OR [aOR], 1.05; 95% CI, 0.64-1.74); lifestyle and comorbidity did not modify this association. A higher BMI (≥25 kg/m2) (aOR, 1.42 [95% CI, 1.02-1.98]), non-Western ethnic origin (aOR, 1.96 [95% CI, 1.34-2.87]), travel to Eastern-Mediterranean, Western-Pacific or South-East Asia regions (aOR, 3.16 [95% CI, 1.71-5.83]) were associated with ESBL-E carriage. Sensitivity analyses confirmed these results; spline analysis supported a BMI-associated risk.Conclusions: In this open population study, current use of acid suppressants was not associated with ESBL-E carriage. Travel to high-endemic regions and non-Western ethnicity were confirmed as risk factors, while a higher BMI emerged as a potential new risk for ESBL-E carriage. [ABSTRACT FROM AUTHOR]

Background: ESBL and plasmid-mediated AmpC (pAmpC)-producing Enterobacteriaceae are frequently found on meat products in Dutch retail, especially on poultry.Objectives: We investigated whether vegetarians are at lower risk of carrying ESBL/pAmpC-producing Escherichia coli/Klebsiella pneumoniae (ESBL-E/K) compared with persons who consume meat.Methods: Vegetarians, pescatarians (vegetarians who eat fish) and non-vegetarians (persons who eat meat at least three times per week) were asked to send in a faecal sample and a questionnaire. ESBL-E/K were cultured and MLSTs were determined. ESBL/pAmpC genes were analysed using PCR and sequencing. The risk of ESBL-E/K carriage in the three study groups was analysed using multivariable logistic regression.Results: Prevalence of ESBL-E/K carriage was 8.0% in vegetarians (63/785; 95% CI 6.3-10.1), 6.9% in pescatarians (27/392; 95% CI 4.8-9.8) and 3.8% in non-vegetarians (14/365; 95% CI 2.3-6.3). Multivariable analysis showed an OR for ESBL-E/K carriage of 2.2 for vegetarians (95% CI 1.2-4.0) and 1.6 for pescatarians (95% CI 0.8-3.2) compared with non-vegetarians. The predominant MLST was E. coli ST131 and the most common ESBL genes were blaCTX-M-15, blaCTX-M-27, blaCTX-M-14 and blaCTX-M-1 in all diet groups. Independent risk factors for ESBL-E/K carriage were travel to Africa/Latin America/Asia (OR 4.6; 95% CI 2.8-7.7) in the past 6 months and rarely/never washing hands before food preparation (OR 2.5; 95% CI 1.2-5.0).Conclusions: Vegetarians and pescatarians did not have a lower risk of ESBL-E/K carriage compared with non-vegetarians, indicating that eating meat is not an important risk factor for ESBL-E/K carriage. [ABSTRACT FROM AUTHOR]

Objectives: To determine the molecular characteristics of ESBL-producing Escherichia coli (ESBL-E) collected during a longitudinal study on an organic broiler farm in order to investigate clonal expansion and horizontal gene transfer.Methods: Isolates were obtained from a longitudinal study performed previously on an organic broiler fattening farm. Samples from individually followed-up broilers, the broiler house, the transport van and persons that took the samples, taken at several timepoints (days 1, 3, 4, 7, 10, 42 and 70) within a production round and during the consecutive one (days 1, 2, 3 and 70), had been investigated for the occurrence of ESBL-E. In the current study, ESBL genes and MLST STs of these ESBL-E were determined. Plasmids were characterized and subtyped.Results: On arrival in round_1, ESBL-E of ST88 predominated, while on days 3, 4, 7 and 10 ST10 was most often found and at slaughter age ST155 and ST1551 prevailed. A shift in STs was also observed in round_2. None of the 35 individually selected broilers followed up in round_1 was positive for the same ESBL-E ST at all sampling times. All isolates carried CTX-M-1 group genes, confirmed as blaCTX-M-1 in 158 isolates. Further analysis of 36 isolates of different STs showed blaCTX-M-1 on IncI1/ST3 plasmids.Conclusions: The rapid dissemination of ESBL-E on this broiler farm was not due to the spread of one specific E. coli clone, but most likely the result of horizontal transfer of an IncI1/ST3 plasmid carrying blaCTX-M-1 resulting in a shift in the predominant ESBL-E population in broilers. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: In recent years, ESBL/AmpC-producing Escherichia coli (ESBL/AmpC-EC) have been isolated with increasing frequency from animals, food, environmental sources and humans. With incomplete and scattered evidence, the contribution to the human carriage burden from these reservoirs remains unclear.Objectives: To quantify molecular similarities between different reservoirs as a first step towards risk attribution.Methods: Pooled data on ESBL/AmpC-EC isolates were recovered from 35 studies in the Netherlands comprising >27 000 samples, mostly obtained between 2005 and 2015. Frequency distributions of ESBL/AmpC genes from 5808 isolates and replicons of ESBL/AmpC-carrying plasmids from 812 isolates were compared across 22 reservoirs through proportional similarity indices (PSIs) and principal component analyses (PCAs).Results: Predominant ESBL/AmpC genes were identified in each reservoir. PCAs and PSIs revealed close human-animal ESBL/AmpC gene similarity between human farming communities and their animals (broilers and pigs) (PSIs from 0.8 to 0.9). Isolates from people in the general population had higher similarities to those from human clinical settings, surface and sewage water and wild birds (0.7-0.8), while similarities to livestock or food reservoirs were lower (0.3-0.6). Based on rarefaction curves, people in the general population had more diversity in ESBL/AmpC genes and plasmid replicon types than those in other reservoirs.Conclusions: Our 'One Health' approach provides an integrated evaluation of the molecular relatedness of ESBL/AmpC-EC from numerous sources. The analysis showed distinguishable ESBL/AmpC-EC transmission cycles in different hosts and failed to demonstrate a close epidemiological linkage of ESBL/AmpC genes and plasmid replicon types between livestock farms and people in the general population. [ABSTRACT FROM AUTHOR]

Background: Commensal bacteria are a reservoir for antimicrobial-resistance genes. In the Netherlands, bacteria producing Extended Spectrum Beta-Lactamases (ESBL) are found on chicken-meat and in the gut of broilers at a high prevalence and the predominant ESBL-gene is the bla CTX-M-1 located on IncI1 plasmids. We aim to determine the fitness costs of this plasmid for the bacterium. We investigated the conjugation dynamics of IncI1 plasmids carrying the bla CTX-M-1 gene in a batch culture and its impact on the population dynamics of three E. coli populations: donors, recipients and transconjugants. The intrinsic growth rate (ψ), maximum density (K) and lag-phase (λ) of the populations were estimated as well as the conjugation coefficient. Loss of the plasmid by transconjugants was either assumed constant or depended on the effective growth rate of the transconjugants. Parameters were estimated from experiments with pure culture of donors, recipients and transconjugants and with mixed culture of donors and recipients with a duration of 24 or 48 hours. Extrapolation of the results was compared to a 3-months experiment in which a mixed culture of recipient and transconjugant was regularly diluted in new medium. Results: No differences in estimated growth parameters (ψ, K or λ) were found between donor, recipient and transconjugant, and plasmid loss was not observed. The conjugation coefficient of transconjugants was 104 times larger than that of the donor. In the 3-months experiment, the proportion of transconjugants did not decrease, indicating no or very small fitness costs. Conclusions: In vitro the IncI1 plasmid carrying the bla CTX-M-1 gene imposes no or negligible fitness costs on its E. coli host, and persists without antimicrobial usage. [ABSTRACT FROM AUTHOR]

Broilers and broiler meat products are highly contaminated with extended spectrum beta-lactamase (ESBL) or plasmid-mediated AmpC beta-lactamase producing Escherichia coli and are considered to be a source for human infections. Both horizontal and vertical transmission might play a role in the presence of these strains in broilers. As not much is known about the presence of these strains in the whole production pyramid, the epidemiology of ESBL/AmpC-producing E. coli in the Dutch broiler production pyramid was examined. Cloacal swabs of Grandparent stock (GPS) birds (one−/two-days (breed A and B), 18 and 31 weeks old (breed A)), one-day old Parent stock birds (breed A and B) and broiler chickens of increasing age (breed A) were selectively cultured to detect ESBL/AmpC-producing isolates. ESBL/AmpC-producing isolates were found at all levels in the broiler production pyramid in both broiler breeds examined. Prevalence was already relatively high at the top of the broiler production pyramid. At broiler farms ESBL/AmpC producing E. coli were still present in the environment of the poultry house after cleaning and disinfection. Feed samples taken in the poultry house also became contaminated with ESBL/AmpC producing E. coli after one or more production weeks. The prevalence of ESBL/AmpC-positive birds at broiler farms increased within the first week from 0–24% to 96–100% independent of the use of antibiotics and stayed 100% until slaughter. In GPS breed A, prevalence at 2 days, 18 weeks and 31 weeks stayed below 50% except when beta-lactam antibiotics were administered. In that case prevalence increased to 100%. Interventions minimizing ESBL/AmpC contamination in broilers should focus on preventing horizontal and vertical spread, especially in relation to broiler production farms. [ABSTRACT FROM AUTHOR]

The important human gastric pathogen Helicobacter pylori is the subject of many studies, and as a consequence it is frequently being transported between national and international laboratories. Unfortunately, common bacterial growth and transport media contain serum- and animal tissue-derived materials, which carry the risk of spreading infectious diseases. We have therefore developed a growth and transport medium for H. pylori, designated ‘Serum- and Animal Tissue-Free Medium’ (SATFM), which does not contain serum- or animal tissue-derived components. SATFM supported growth of H. pylori isolates to similar levels as obtained with serum-supplemented Brucella medium, and SATFM with 0.5% agar supported transport and storage of H. pylori strains, as 4/4 reference strains and 11/11 clinical isolates survived for at least 3 days at room temperature in SATFM, with some strains (2/15) even surviving for up to 7 days. In conclusion, SATFM can be used both as transport and growth medium for H. pylori. The formulation of SATFM may allow its use in international transport of H. pylori, and may also allow certified use in immunization studies requiring growth of H. pylori and other bacterial pathogens. [ABSTRACT FROM AUTHOR]

Reducing antimicrobial use (AMU) in livestock may be one of the keys to limit the emergence of antimicrobial resistance (AMR) in bacterial populations, including zoonotic pathogens. This study assessed the temporal association between AMU in livestock and AMR among Campylobacter isolates from human infections in the Netherlands between 2004 - 2020. Moreover, the associations between AMU and AMR in livestock and between AMR in livestock and AMR in human isolates were assessed. AMU and AMR data per antimicrobial class (tetracyclines, macrolides and fluoroquinolones) for Campylobacter jejuni and Campylobacter coli from poultry, cattle, and human patients were retrieved from national surveillance programs. Associations were assessed using logistic regression and the Spearman correlation test. Overall, there was an increasing trend in AMR among human C. jejuni / coli isolates during the study period, which contrasted with a decreasing trend in livestock AMU. In addition, stable trends in AMR in broilers were observed. No significant associations were observed between AMU and AMR in domestically produced broilers. Moderate to strong positive correlations were found between the yearly prevalence of AMR in broiler and human isolates. Reducing AMU in Dutch livestock alone may therefore not be sufficient to tackle the growing problem of AMR in Campylobacter among human cases in the Netherlands. More insight is needed regarding the population genetics and the evolutionary processes involved in resistance and fitness among Campylobacter.

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.