Background: The Netherlands is currently considered a low endemic country for carbapenem-resistant Enterobacterales (CRE) and carbapenemase-producing Enterobacterales (CPE), experiencing only... Show moreBackground: 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. Show less
Recent mathematical results for the noisy Kuramoto model on a 2-community network may explain some phenomena observed in the functioning of the suprachiasmatic nucleus (SCN). Specifically, these... Show moreRecent mathematical results for the noisy Kuramoto model on a 2-community network may explain some phenomena observed in the functioning of the suprachiasmatic nucleus (SCN). Specifically, these findings might explain the types of transitions to a state of the SCN in which 2 components are dissociated in phase, for example, in phase splitting. In contrast to previous studies, which required additional time-delayed coupling or large variation in the coupling strengths and other variations in the 2-community model to exhibit the phase-split state, this model requires only the 2-community structure of the SCN to be present. Our model shows that a change in the communication strengths within and between the communities due to external conditions, which changes the excitation-inhibition (E/I) balance of the SCN, may result in the SCN entering an unstable state. With this altered E/I balance, the SCN would try to find a new stable state, which might in some circumstances be the split state. This shows that the 2-community noisy Kuramoto model can help understand the mechanisms of the SCN and explain differences in behavior based on actual E/I balance. Show less
