Molecular characteristics of carbapenemase-producing Enterobacterales in the Netherlands; results of the 2014–2018 national laboratory surveillance

Objectives: Carbapenem resistance mediated by mobile genetic elements has emerged worldwide and has become a major public health threat. To gain insight into the molecular epidemiology of carbapenem resistance in The Netherlands, Dutch medical microbiology laboratories are requested to submit suspected carbapenemase-producing Enterobacterales (CPE) to the National Institute for Public Health and the Environment as part of a national surveillance system. Methods: Meropenem MICs and species identification were confirmed by E-test and MALDI-TOF and carbapenemase production was assessed by the Carbapenem Inactivation Method. Of all submitted CPE, one species/carbapenemase gene combination per person per year was subjected to next-generation sequencing (NGS). Results: In total, 1838 unique isolates were received between 2014 and 2018, of which 892 were unique CPE isolates with NGS data available. The predominant CPE species were Klebsiella pneumoniae (n = 388, 43%), Escherichia coli (n = 264, 30%) and Enterobacter cloacae complex (n = 116, 13%). Various carbapenemase alleles of the same carbapenemase gene resulted in different susceptibilities to meropenem and this effect varied between species. Analyses of NGS data showed variation of prevalence of carbapenemase alleles over time with blaOXA-48 being predominant (38%, 336/892), followed by blaNDM-1 (16%, 145/892). For the first time in the Netherlands, blaOXA-181, blaOXA-232 and blaVIM-4 were detected. The genetic background of K. pneumoniae and E. coli isolates was highly diverse. Conclusions: The CPE population in the Netherlands is diverse, suggesting multiple introductions. The predominant carbapenemase alleles are blaOXA-48 and blaNDM-1. There was a clear association between species, carbapenemase allele and susceptibility to meropenem

National laboratory-based surveillance system for antimicrobial resistance: a successful tool to support the control of antimicrobial resistance in the Netherlands

An important cornerstone in the control of antimicrobial resistance (AMR) is a well-designed quantitative system for the surveillance of spread and temporal trends in AMR. Since 2008, the Dutch national AMR surveillance system, based on routine data from medical microbiological laboratories (MMLs), has developed into a successful tool to support the control of AMR in the Netherlands. It provides background information for policy making in public health and healthcare services, supports development of empirical antibiotic therapy guidelines and facilitates in-depth research. In addition, participation of the MMLs in the national AMR surveillance network has contributed to sharing of knowledge and quality improvement. A future improvement will be the implementation of a new semantic standard together with standardised data transfer, which will reduce errors in data handling and enable a more real-time surveillance. Furthermore, the

Molecular characterization of MRSA collected during national surveillance between 2008 and 2019 in the Netherlands

Background.Although the Netherlands is a country with a low endemic level, methicillin-resistant Staphylococcus aureus (MRSA) poses a significant health care problem. Therefore, high coverage national MRSA surveillance has been in place since 1989. To monitor possible changes in the type-distribution and emergence of resistance and virulence, MRSA isolates are molecularly characterized.Methods.All 43,321 isolates from 36,520 persons, collected 2008-2019, were typed by multiple-locus variable number tandem repeats analysis (MLVA) with simultaneous PCR detection of the mecA, mecC and lukF-PV genes, indicative for PVL. Next-generation sequencing data of 4991 isolates from 4798 persons were used for whole genome multi-locus sequence typing (wgMLST) and identification of resistance and virulence genes.Results.We show temporal change in the molecular characteristics of the MRSA population with the proportion of PVL-positive isolates increasing from 15% in 2008-2010 to 25% in 2017-2019. In livestock-associated MRSA obtained from humans, PVL-positivity increases to 6% in 2017-2019 with isolates predominantly from regions with few pig farms. wgMLST reveals the presence of 35 genogroups with distinct resistance, virulence gene profiles and specimen origin. Typing shows prolonged persistent MRSA carriage with a mean carriage period of 407 days. There is a clear spatial and a weak temporal relationship between isolates that clustered in wgMLST, indicative for regional spread of MRSA strains.Conclusions.Using molecular characterization, this exceptionally large study shows genomic changes in the MRSA population at the national level. It reveals waxing and waning of types and genogroups and an increasing proportion of PVL-positive MRSA.A group of bacteria that cause difficult-to-treat infections in humans is methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to monitor changes in the spread of MRSA, their disease causing potential and resistance to antibiotics used to treat MRSA infections. MRSA from patients and their contacts in the Netherlands were collected over a period of 12 years and characterized. This revealed new types of MRSA emerged and others disappeared. An increasing number of MRSA produces a protein called PVL toxin, enabling MRSA to cause more severe infections. Also, some people appear to carry MRSA without any disease for more than a year. These findings suggest an increasing disease potential of MRSA and possible unnoticed sources of infection. Consequently, it is important to maintain monitoring of these infections to minimize MRSA spread.Schouls et al. characterize 43,321 methicillin-resistant Staphylococcus aureus (MRSA) isolates obtained between 2008 and 2019 in the Netherlands. Genomic changes occur in the MRSA population, with increases in the proportion of PVL-positive MRSA.Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc

Hypertensive organ damage in patients with vascular disease

Hypertension is one of the most common vascular risk factors, and is an important cause of development of different vascular diseases. The main aim of this thesis was to determine the burden of hypertension-associated vascular diseases and end-organ damage in patients with manifest vascular disease. Patients with manifest vascular diseases are at high risk for recurrent vascular diseases. We studied the effect of the metabolic syndrome and type 2 diabetes mellitus on the occurrence of cardiovascular events in patients with hypertension and manifest vascular disease, as well as in patients with peripheral arterial occlusive disease. The prevalence of the metabolic syndrome among these patients was higher compared to patients without vascular diseases. Hypertensive patients with the metabolic syndrome but without type 2 diabetes mellitus had a 41% higher risk of vascular death and a 40% higher risk of myocardial infarction and sudden death. Among patients with peripheral arterial occlusive disease, patients with the metabolic syndrome had a 51% higher risk of vascular events compared to patients without the metabolic syndrome. A decreasing body mass index during follow-up highly influenced the development and resolution of the metabolic syndrome. In the general population, renal mass and renal function are declining during life, and elevated blood pressure is generally associated with renal function decline. A considerable decline in renal function was present among patients with vascular disease, and blood pressure was a strong risk factor for renal function deterioration in patients with albuminuria and atherosclerotic vascular disease. When separate and combined effects of decreased renal function and albuminuria on the occurrence of vascular diseases and mortality were investigated in patients with manifest vascular disease, the combination of decreased renal function and albuminuria accounted for a 2.27-fold increased risk of vascular events. When albuminuria or decreased renal function were present, this risk was only moderately increased. Vascular risk factors including elevated blood pressure have been identified as risk factors for cerebral white matter lesions (WML) and cerebral atrophy. Among patients with manifest vascular disease, blood pressure was not associated with the presence of WML, irrespective of the presence of diabetes or the localization of vascular disease. Also no association was present between blood pressure and the progression of cerebral atrophy. However, the magnitude of changes in brain tissue volume and ventricular volume in patients with vascular disease was comparable to the physiological changes described in healthy populations at a much higher age. In the last part of this thesis, we examined time trends in vascular risk factors and medication use in patients referred to a vascular specialist with manifest vascular disease or type 2 diabetes mellitus in the period of 1996 to 2007. From 1996 to 2007, the prevalence of obesity increased from 14% to 24%, and no change in smoking behaviour was observed. The prevalence of elevated cholesterol levels and elevated blood pressure declined during the observation period while the use of lipid-lowering, blood pressure-lowering and antithrombotic medication at referral increased

Trends in vascular risk factors and medication use in patients with various manifestations of vascular diseases or type 2 diabetes mellitus from 1996 to 2007: the Second Manifestations of Arterial Disease (SMART) Study

Aims: To investigate time trends in vascular risk factors and medication use for patients referred to a vascular specialist with manifest vascular disease or type 2 diabetes mellitus (DM2). Methods and results: Change in risk factor profile and medication use at referral over a 12-year period was evaluated and compared between patients with coronary heart disease, cerebrovascular disease, peripheral arterial disease, abdominal aortic aneurysm, and DM2, who participated in the Second Manifestations of ARTerial disease study in the period of 1996-2007. A total of 4731 patients were included (mean age 59+/-11 years, 75% male) in the period 1996-2007. Obesity (body mass index >=30 kg/m2) prevalence increased from 14 to 24%, and no change in smoking behavior was observed. The prevalence of hyperlipidemia (total cholesterol >=4.5 mmol/l or low-density lipoprotein cholesterol >=2.5 mmol/l) at referral declined from 92% in 1996-1997 to 45% in 2006-2007. The proportion of patients with blood pressure above 140/90 mmHg decreased from 66 to 51%. The use of lipid-lowering, blood pressure-lowering, and antithrombotic medication at referral increased over the observation period. Conclusion: An improvement in risk factor profile was seen in patients referred with manifest vascular disease or DM2 over a 12-year period. Nevertheless, the prevalence of modifiable risk factors is still high leaving patients at elevated vascular ris

Third-generation cephalosporin and carbapenem resistance in Streptococcus mitis/oralis. Results from a nationwide registry in the Netherlands

Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc