Epidemiological characterisation of the first 785 SARS-CoV-2 Omicron variant cases in Denmark, December 2021.

By 9 December 2021, 785 SARS-CoV-2 Omicron variant cases have been identified in Denmark. Most cases were fully (76%) or booster-vaccinated (7.1%); 34 (4.3%) had a previous SARS-CoV-2 infection. The majority of cases with available information reported symptoms (509/666; 76%) and most were infected in Denmark (588/644; 91%). One in five cases cannot be linked to previous cases, indicating widespread community transmission. Nine cases have been hospitalised, one required intensive care and no deaths have been registered.

Electronic reporting of diagnostic laboratory test results from all healthcare sectors is a cornerstone of national preparedness and control of COVID-19 in Denmark.

The COVID-19 pandemic has led to an unprecedented demand for real-time surveillance data in order to inform critical decision makers regarding the management of the pandemic. The aim of this review was to describe how the Danish national microbiology database, MiBa, served as a cornerstone for providing data to the real-time surveillance system by linkage to other nationwide health registries. The surveillance system was established on an existing IT health infrastructure and a close network between clinical microbiologists, information technology experts, and public health officials. In 2020, testing capacity for SARS-CoV-2 was ramped up from none to over 10,000 weekly PCR tests per 100,000 population. The crude incidence data mirrored this increase in testing. Real-time access to denominator data and patient registries enabled adjustments for fluctuations testing activity, providing robust data on crude SARS-CoV-2 incidence during the changing diagnostic and management strategies. The use of the same data for different purposes, for example, final laboratory reports, information to the public, contact tracing, public health, and science, has been a critical asset for the pandemic response. It has also raised issues concerning data protection and critical capacity of the underlying technical systems and key resources. However, even with these limitations, the setup has enabled decision makers to adopt timely interventions. The experiences from COVID-19 may motivate a transformation from traditional indicator-based public health surveillance to an all-encompassing information system based on access to a comprehensive set of data sources, including diagnostic and reference microbiology.

Reliable Condensation Curing Silicone Elastomers with Tailorable Properties.

The long-term stability of condensation curing silicone elastomers can be affected by many factors such as curing environment, cross-linker type and concentration, and catalyst concentration. Mechanically unstable silicone elastomers may lead to undesirable application failure or reduced lifetime. This study investigates the stability of different condensation curing silicone elastomer compositions. Elastomers are prepared via the reaction of telechelic silanol-terminated polydimethylsiloxane (HO-PDMS-OH) with trimethoxysilane-terminated polysiloxane ((MeO)3Si-PDMS-Si(OMe)3) and ethoxy-terminated octakis(dimethylsiloxy)-T8-silsesquioxane ((QMOEt)8), respectively. Two post-curing reactions are found to significantly affect both the stability of mechanical properties over time and final properties of the resulting elastomers: Namely, the condensation of dangling and/or unreacted polymer chains, and the reaction between cross-linker molecules. Findings from the stability study are then used to prepare reliable silicone elastomer coatings. Coating properties are tailored by varying the cross-linker molecular weight, type, and concentration. Finally, it is shown that, by proper choice of all three parameters, a coating with excellent scratch resistance and electrical breakdown strength can be produced even without an addition of fillers.

Potential widespread denitrosylation of brain proteins following prolonged restraint: proposed links between stress and central nervous system disease.

The biochemical pathways by which aberrant psychophysiological stress promotes neuronal damage and increases the risks for central nervous system diseases are not well understood. In light of previous findings that psychophysiological stress, modeled by animal restraint, can increase the activities and expression levels of nitric oxide synthase isoforms in multiple brain regions, we examined the effects of restraint, for up to 6 h, on levels of S-nitrosylated proteins and NOx (nitrite + nitrate), a marker for high-level nitric oxide generation, in the brains of rats. Results identify functionally-diverse protein targets of S-nitrosylation in the brain, in vivo, and demonstrate the potential for widespread loss of protein nitrosothiols following prolonged restraint despite a concomitant increase in NOx levels. Since physiological levels of protein S-nitrosylation can protect neurons by maintaining redox homeostasis, by limiting excitatory neurotransmission, and by inhibiting apoptotic and inflammatory pathways, we propose that over-activation of protein denitrosylation pathways following sustained or repeated stress may facilitate neural damage and early stages of stress-related central nervous system disease.

Salt-Induced Control of the Grafting Density in Poly(ethylene glycol) Brush Layers by a Grafting-to Approach.

In this work, a method to obtain control of the grafting density during the formation of polymer brush layers by the grafting-to method of thiolated poly(ethylene glycol) onto gold is presented. The grafting density of the polymer chains was adjusted by adding Na2SO4 in concentrations between 0.2 and 0.9 M to the aqueous polymer solution during the grafting process. The obtained grafting densities ranged from 0.26 to 1.60 chains nm-2, as determined by surface plasmon resonance. The kinetics of the grafting process were studied in situ by a quartz crystal microbalance with dissipation, and a mushroom to brush conformational transition was observed when the polymer was grafted in the presence of Na2SO4. The transition from mushroom to brush was only observed for long periods of grafting, highlighting the importance of time to obtain high grafting densities. Finally, the prepared brush layer with the highest grafting density showed high resistance to the adsorption of bovine serum albumin, while layers with a lower grafting density showed only limited resistance.

Multiple hospital outbreaks of vanA Enterococcus faecium in Denmark, 2012-13, investigated by WGS, MLST and PFGE.

OBJECTIVES: In Denmark, the incidence of vancomycin-resistant Enterococcus faecium (VREfm) has increased since 2012. The aim of this study was to investigate the epidemiology and clonal relatedness of VREfm isolates in Danish hospitals in 2012-13 using WGS. The second aim was to evaluate if WGS-based typing could replace PFGE for typing of VREfm. METHODS: A population-based study was conducted including all VREfm isolates submitted for national surveillance from January 2012 to April 2013. All isolates were investigated by WGS, MLST and PFGE. RESULTS: One-hundred and thirty-two isolates were included. The majority of the isolates were from clinical samples (77%). Gastroenterology/abdominal surgery (29%) and ICUs (29%) were the predominant departments with VREfm. Genomics revealed a polyclonal structure of the VREfm outbreak. Seven subgroups of 3-44 genetically closely related isolates (separated by <17 SNPs) were identified using WGS. Direct or indirect transmission of VREfm between patients and intra- and inter-regional spreading clones was observed. We identified 10 STs. PFGE identified four major clusters (13-43 isolates) and seven minor clusters (two to three isolates). The results from the typing methods were highly concordant. However, WGS-based typing had the highest discriminatory power. CONCLUSIONS: This study emphasizes the importance of infection control measures to limit transmission of VREfm between patients. However, the diversity of the VREfm isolates points to the fact that other important factors may also affect the VREfm increase in Denmark. Finally, WGS is suitable for typing of VREfm and has replaced PFGE for typing of VREfm in Denmark.

Limited similarity between plasmids encoding CTX-M-1 ß-lactamase in Escherichia coli from humans, pigs, cattle, organic poultry layers and horses in Denmark.

CTX-M-1 is a common extended-spectrum ß-lactamase (ESBL) in Escherichia coli from animals and is often detected among human clinical isolates. The objective of this study was to investigate the epidemiological relationship between CTX-M-1-producing E. coli isolated from patients and animals in Denmark between 2006 and 2010. In total, 65 CTX-M-1-producing isolates from patients (n=22), pigs (n=21), cattle (n=4), organic poultry layers (n=3) and horses (n=15) were typed by pulsed-field gel electrophoresis (PFGE). Plasmids harbouring blaCTX-M-1 were characterised by S1 PFGE, PCR-based replicon typing, plasmid multilocus sequence typing, restriction fragment length polymorphism, and sequencing. Human and animal strains were unrelated based on PFGE. IncI1 was more common in human isolates (13/22) than in animal isolates (7/43), whereas the opposite trend was observed for IncN (5/22 human isolates and 24/43 animal isolates). Full characterisation of the plasmids harbouring blaCTX-M-1 revealed host-specific patterns in the distribution of plasmid types, with specific IncI1, IncN and IncH1 plasmid subtypes being predominant in humans, livestock and horses, respectively. Three indistinguishable human, bovine and porcine IncI1/ST49 plasmids had high nucleotide sequence homology and differed by the presence of IS66 elements in the bovine plasmid and the absence of one gene within the microcin-encoding operon in the human plasmid. In conclusion, this work suggests a minor contribution by animals to the occurrence of CTX-M-1 in human E. coli infections in Denmark during the study period.

Characterization of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli obtained from Danish pigs, pig farmers and their families from farms with high or no consumption of third- or fourth-generation cephalosporins.

OBJECTIVES: To compare and characterize extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli from pigsties, pig farmers and their families on farms with previous high or no use of third- or fourth-generation cephalosporins. METHODS: Twenty farms with no third- or fourth-generation cephalosporin use and 19 herds with previous frequent use were included. The ESBL-producing isolates detected in humans and pigs were characterized by ESBL genotype, PFGE, susceptibility to non-ß-lactam antibiotics and phylotype, and selected isolates were characterized by multilocus sequence typing (MLST). Furthermore, transferability of bla(CTX-M-)1 from both human and pig isolates was studied and plasmid incompatibility groups were defined. The volunteers answered a questionnaire including epidemiological risk factors for carriage of ESBL-producing E. coli. RESULTS: ESBL-producing E. coli was detected in pigs on 79% of the farms with high consumption of cephalosporins compared with 20% of the pigs on farms with no consumption. ESBL-producing E. coli was detected in 19 of the 195 human participants and all but one had contact with pigs. The genes found in both humans and pigs at the same farms were blaCTX-M-1 (eight farms), bla(CTX-M-14) (one farm) and bla(SHV-12) (one farm). At four farms ESBL-producing E. coli isolates with the same CTX-M enzyme, phylotype, PFGE type and MLST type were detected in both pigs and farmers. The majority of the plasmids with bla(CTX-M-1) were transferable by conjugation and belonged to incompatibility group IncI1, IncF, or IncN. CONCLUSIONS: The present study shows an increased frequency of ESBL-producing E. coli on farms with high consumption of third- or fourth-generation cephalosporins and indicates transfer of either ESBL-producing E. coli or plasmids between pigs and farmers.

Characterization of third-generation cephalosporin-resistant Escherichia coli from bloodstream infections in Denmark.

The aim of the study was to investigate the molecular epidemiology of 87 third-generation cephalosporin-resistant Escherichia coli (3GC-R Ec) from bloodstream infections in Denmark from 2009. Sixty-eight of the 87 isolates were extended-spectrum beta-lactamase (ESBL) producers, whereas 17 isolates featured AmpC mutations only (without a coexpressed ESBL enzyme) and 2 isolates were producing CMY-22. The majority (82%) of the ESBL-producing isolates in our study were CTX-M-15 producers and primarily belonged to phylogroup B2 (54.4%) or D (23.5%). Further, one of the two CMY-22-producing isolates belonged to B2, whereas only few of the other AmpCs isolates belonged to B2 and D. Pulsed-field gel electrophoresis revealed that both clonal and nonclonal spread of 3GC-R Ec occurred. ST131 was detected in 50% of ESBL-producing isolates. The remaining ESBL-producing isolates belonged to 17 other sequence types (STs), including several other internationally spreading STs (e.g., ST10, ST69, and ST405). The majority (93%) of the ESBL-producing isolates and one of the CMY-22-producing isolates were multiresistant. In conclusion, 3GC-R in bacteriaemic E. coli in Denmark was mostly due to ESBL production, overexpression of AmpC, and to a lesser extent to plasmid-mediated AmpC. The worldwide disseminated CTX-M-15-ST131 was strongly represented in this collection of Danish, bacteriaemic E. coli isolates.

Pseudoalteromonas spp. serve as initial bacterial attractants in mesocosms of coastal waters but have subsequent antifouling capacity in mesocosms and when embedded in paint.

The purpose of the present study was to determine if the monoculture antifouling effect of several pigmented pseudoalteromonads was retained in in vitro mesocosm systems using natural coastal seawater and when the bacteria were embedded in paint used on surfaces submerged in coastal waters. Pseudoalteromonas piscicida survived on a steel surface and retained antifouling activity for at least 53 days in sterile seawater, whereas P. tunicata survived and had antifouling activity for only 1 week. However, during the first week, all Pseudoalteromonas strains facilitated rather than prevented bacterial attachment when used to coat stainless steel surfaces and submerged in mesocosms with natural seawater. The bacterial density on surfaces coated with sterile growth medium was 10(5) cells/cm(2) after 7 days, whereas counts on surfaces precoated with Pseudoalteromonas were significantly higher, at 10(6) to 10(8) cells/cm(2). However, after 53 days, seven of eight Pseudoalteromonas strains had reduced total bacterial adhesion compared to the control. P. piscicida, P. antarctica, and P. ulvae remained on the surface, at levels similar to those in the initial coating, whereas P. tunicata could not be detected. Larger fouling organisms were observed on all plates precoated with Pseudoalteromonas; however, plates coated only with sterile growth medium were dominated by a bacterial biofilm. Suspensions of a P. piscicida strain and a P. tunicata strain were incorporated into ship paints (Hempasil x3 87500 and Hempasil 77500) used on plates that were placed at the Hempel A/S test site in Jyllinge Harbor. For the first 4 months, no differences were observed between control plates and treated plates, but after 5 to 6 months, the control plates were more fouled than the plates with pseudoalteromonad-based paint. Our study demonstrates that no single laboratory assay can predict antifouling effects and that a combination of laboratory and real-life methods must be used to determine the potential antifouling capability of new agents or organisms.

Concurrent emergence of multidrug resistance and heat resistance by CTX-M-15-encoding conjugative plasmids in Klebsiella pneumoniae.

A plasmid-encoded ClpK protein was recently identified as a predictor of a heat-resistant phenotype in the opportunistic pathogen Klebsiella pneumoniae. This study was undertaken to evaluate the presence of the clpK gene in extended-spectrum ß-lactamase (ESBL)-producing K. pneumoniae and to assess the probable co-transfer of multi-resistance with the heat resistance phenotype. A Danish collection of 80 ESBL-producing K. pneumoniae bloodstream infection isolates was screened for clpK by colony hybridization. Nineteen isolates (24%) were positive for clpK; some of them representing major clones identified in Denmark. Among these, nine isolates belonged to a single K. pneumoniae CTX-M-15 clone with sequence type (ST)16 exhibiting a heat-resistant phenotype. This clone has a multi-hospital occurrence and has also been detected outside Denmark. Horizontal co-transfer of multiple antibiotic resistances, including the CTX-M-15 resistance determinant, and the heat resistance phenotype was observed. Thus, the clpK gene is harbored by different ESBL-producing K. pneumoniae isolates including a clone of ST16 internationally spread. The co-localization of clpK on transferable ESBL-encoding plasmids allowing co-dissemination of multiple drug resistance with bacterial heat resistance is a highly interesting phenomenon that may further complicate the prevention of spreading of certain successful clones of multi-resistant K. pneumoniae.

Porcine-origin gentamicin-resistant Enterococcus faecalis in humans, Denmark.

During 2001-2002, high-level gentamicin-resistant (HLGR) Enterococcus faecalis isolates were detected in 2 patients in Denmark who had infective endocarditis and in pigs and pork. Our results demonstrate that these isolates belong to the same clonal group, which suggests that pigs are a source of HLGR E. faecalis infection in humans.