Rationale and protocol of the StayFitLonger study: a multicentre trial to measure efficacy and adherence of a home-based computerised multidomain intervention in healthy older adults.

BACKGROUND: In older adults, multidomain training that includes physical and cognitive activities has been associated with improvement of physical and cognitive health. The goal of the multisite StayFitLonger study is to assess a home-based computerised training programme, which combines physical exercises, stimulating cognitive activities and virtual coaching. METHODS: One hundred twenty-eight cognitively healthy older adults will be recruited from the community in Switzerland, Canada and Belgium. The study will comprise (1) a 26-week double-blind randomized controlled efficacy trial and (2) a 22-week pragmatic adherence sub-study. In the efficacy trial, participants will be randomly assigned to an experimental or an active control intervention. In the experimental intervention, participants will use the StayFitLonger programme, which is computerised on a tablet and provides content that combines physical activities with a focus on strength and balance, as well as divided attention, problem solving and memory training. Outcomes will be measured before and after 26 weeks of training. The primary efficacy outcome will be performance on the "Timed-Up & Go" test. Secondary outcomes will include measures of frailty, cognition, mood, fear of falling, quality of life, and activities of daily living. Age, sex, education, baseline cognition, expectation, and adherence will be used as moderators of efficacy. Following the 26-week efficacy trial, all participants will use the experimental programme meaning that participants in the control group will 'cross over' to receive the StayFitLonger programme for 22 weeks. Adherence will be measured in both groups based on dose, volume and frequency of use. In addition, participants' perception of the programme and its functionalities will be characterised through usability, acceptability and user experience. DISCUSSION: This study will determine the efficacy, adherence and participants' perception of a home-based multidomain intervention programme and its functionalities. This will allow for further development and possible commercialization of a scientifically validated training programme. TRIAL REGISTRATION: ClinicalTrials.gov , NCT04237519 Registered on January 22, 2020 - Retrospectively registered.

Local adaptation (mostly) remains local: reassessing environmental associations of climate-related candidate SNPs in Arabidopsis halleri.

Numerous landscape genomic studies have identified single-nucleotide polymorphisms (SNPs) and genes potentially involved in local adaptation. Rarely, it has been explicitly evaluated whether these environmental associations also hold true beyond the populations studied. We tested whether putatively adaptive SNPs in Arabidopsis halleri (Brassicaceae), characterized in a previous study investigating local adaptation to a highly heterogeneous environment, show the same environmental associations in an independent, geographically enlarged set of 18 populations. We analysed new SNP data of 444 plants with the same methodology (partial Mantel tests, PMTs) as in the original study and additionally with a latent factor mixed model (LFMM) approach. Of the 74 candidate SNPs, 41% (PMTs) and 51% (LFMM) were associated with environmental factors in the independent data set. However, only 5% (PMTs) and 15% (LFMM) of the associations showed the same environment-allele relationships as in the original study. In total, we found 11 genes (31%) containing the same association in the original and independent data set. These can be considered prime candidate genes for environmental adaptation at a broader geographical scale. Our results suggest that selection pressures in highly heterogeneous alpine environments vary locally and signatures of selection are likely to be population-specific. Thus, genotype-by-environment interactions underlying adaptation are more heterogeneous and complex than is often assumed, which might represent a problem when testing for adaptation at specific loci.

Identifying new sex-linked genes through BAC sequencing in the dioecious plant Silene latifolia.

BACKGROUND: Silene latifolia represents one of the best-studied plant sex chromosome systems. A new approach using RNA-seq data has recently identified hundreds of new sex-linked genes in this species. However, this approach is expected to miss genes that are either not expressed or are expressed at low levels in the tissue(s) used for RNA-seq. Therefore other independent approaches are needed to discover such sex-linked genes. RESULTS: Here we used 10 well-characterized S. latifolia sex-linked genes and their homologs in Silene vulgaris, a species without sex chromosomes, to screen BAC libraries of both species. We isolated and sequenced 4 Mb of BAC clones of S. latifolia X and Y and S. vulgaris genomic regions, which yielded 59 new sex-linked genes (with S. vulgaris homologs for some of them). We assembled sequences that we believe represent the tip of the Xq arm. These sequences are clearly not pseudoautosomal, so we infer that the S. latifolia X has a single pseudoautosomal region (PAR) on the Xp arm. The estimated mean gene density in X BACs is 2.2 times lower than that in S. vulgaris BACs, agreeing with the genome size difference between these species. Gene density was estimated to be extremely low in the Y BAC clones. We compared our BAC-located genes with the sex-linked genes identified in previous RNA-seq studies, and found that about half of them (those with low expression in flower buds) were not identified as sex-linked in previous RNA-seq studies. We compiled a set of ~70 validated X/Y genes and X-hemizygous genes (without Y copies) from the literature, and used these genes to show that X-hemizygous genes have a higher probability of being undetected by the RNA-seq approach, compared with X/Y genes; we used this to estimate that about 30% of our BAC-located genes must be X-hemizygous. The estimate is similar when we use BAC-located genes that have S. vulgaris homologs, which excludes genes that were gained by the X chromosome. CONCLUSIONS: Our BAC sequencing identified 59 new sex-linked genes, and our analysis of these BAC-located genes, in combination with RNA-seq data suggests that gene losses from the S. latifolia Y chromosome could be as high as 30 %, higher than previous estimates of 10-20%.

The roles of genetic drift and natural selection in quantitative trait divergence along an altitudinal gradient in Arabidopsis thaliana.

Understanding how natural selection and genetic drift shape biological variation is a central topic in biology, yet our understanding of the agents of natural selection and their target traits is limited. We investigated to what extent selection along an altitudinal gradient or genetic drift contributed to variation in ecologically relevant traits in Arabidopsis thaliana. We collected seeds from 8 to 14 individuals from each of 14 A. thaliana populations originating from sites between 800 and 2700 m above sea level in the Swiss Alps. Seed families were grown with and without vernalization, corresponding to winter-annual and summer-annual life histories, respectively. We analyzed putatively neutral genetic divergence between these populations using 24 simple sequence repeat markers. We measured seven traits related to growth, phenology and leaf morphology that are rarely reported in A. thaliana and performed analyses of altitudinal clines, as well as overall QST-FST comparisons and correlation analyses among pair-wise QST, FST and altitude of origin differences. Multivariate analyses suggested adaptive differentiation along altitude in the entire suite of traits, particularly when expressed in the summer-annual life history. Of the individual traits, a decrease in rosette leaf number in the vegetative state and an increase in leaf succulence with increasing altitude could be attributed to adaptive divergence. Interestingly, these patterns relate well to common within- and between-species trends of smaller plant size and thicker leaves at high altitude. Our results thus offer exciting possibilities to unravel the underlying mechanisms for these conspicuous trends using the model species A. thaliana.

Evaluation of treatment outcomes for Stenotrophomonas maltophilia bacteraemia.

OBJECTIVE: The goal of this study was to retrospectively collect data about treatment outcomes in patients diagnosed with Stenotrophomonas maltophilia bacteraemia over a period of 20 years and evaluate these data with respect to the efficacy of treatment options. METHODS: The setting was a 700-bed tertiary care hospital in a large urban area. Hospital databases and medical records provided information about episodes of S. maltophilia, patient characteristics and treatment outcomes. Patients with at least one positive blood culture for S. maltophilia were included in the study. Data were analysed with respect to clinical improvement and mortality ≤30 days after the onset of infection. We compared patient characteristics, laboratory values and treatments by using the Chi-square or Fisher's exact tests and the Mann-Whitney test. RESULTS: We investigated 27 patients with S. maltophilia bacteraemia. The focus of infection was a central venous catheter in 18 (67 %) cases. The 30-day mortality rate was 11 %. All patients who were treated with an antibiotic that was effective in vitro against the pathogen recovered clinically and survived ≥30 days after the onset of infection. The most frequently used antibiotic was trimethoprim-sulfamethoxazole administered alone or in combination with a fluoroquinolone. CONCLUSIONS: Despite the fact that S. maltophilia is resistant to multiple antibiotics, the prognosis for patients with S. maltophilia bacteraemia is good when they are treated with antibiotics that are effective against this pathogen in vitro.

Patterns of molecular evolution in dioecious and non-dioecious Silene.

Dioecy (i.e. having separate sexes) is a rather rare breeding system in flowering plants. Such rareness may result from a high probability of extinction in dioecious species because of less efficient dispersal and the costs of sexual selection, which are expected to harm dioecious species' survival on the long term. These handicaps should decrease the effective population size (Ne) of dioecious species, which in turn should reduce the efficacy of selection. Moreover, sexual selection in dioecious species is expected to specifically affect some genes, which will evolve under positive selection. The relative contribution of these effects is currently unknown and we tried to disentangle them by comparing sequence evolution between dioecious and non-dioecious species in the Silene genus (Caryophyllaceae), where dioecy has evolved at least twice. For the dioecious species in the section Melandrium, where dioecy is the oldest, we found a global reduction of purifying selection, while on some, male-biased genes, positive selection was found. For section Otites, where dioecy evolved more recently, we found no significant differences between dioecious and non-dioecious species. Our results are consistent with the view that dioecy is an evolutionary dead end in flowering plants, although other scenarios for explaining reduced Ne cannot be ruled out. Our results also show that contrasting forces act on the genomes of dioecious plants, and suggest that some time is required before the genome of such plants bears the footprints of dioecy.

Increasing prevalence of ciprofloxacin resistance in extended-spectrum-ß-lactamase-producing Escherichia coli urinary isolates.

PURPOSE: To describe the incidence and drug susceptibility profiles of uropathogenic extended-spectrum-ß-lactamase-producing Escherichia coli (ESBL-EC) during a 10-year period and to identify differences in resistance patterns between urological and non-urological ESBL-EC isolates. METHODS: Retrospective analysis of 191,564 urine samples obtained during 2001 to 2010 at the University Hospital Basel, Switzerland. The computerized database of the Clinical Microbiology Laboratory and the Division of Infectious Diseases and Hospital Epidemiology was used to identify ESBL-EC positive urine samples. ESBL-EC isolates were stratified according their origin into two groups: Urology and non-Urology isolates. RESULTS: The rate of ESBL-EC positive urine samples increased significantly during the study period (3 in 2001 compared to 55 in 2010, p < 0.05). The most active agents were imipenem, meropenem, and fosfomycin (100%), followed by amikacin (99.1%) and nitrofurantoin (84%). The least active substances were ampicillin-clavulanate (20%), sulfamethoxazole (28%), and ciprofloxacin (29.6%). ESBL-EC isolates from urological and non-urological patients showed similar susceptibility profiles. However, ESBL-EC isolates from urological patients were significantly less susceptible to ciprofloxacin compared to non-urological isolates (14.7 vs. 32.7%, p < 0.05). CONCLUSIONS: The rate of urinary ESBL-EC isolates is increasing. Their susceptibility to nitrofurantoin, fosfomycin, and carbapenems is excellent, whereas ampicillin-clavulanate, sulfamethoxazole, and ciprofloxacin demonstrate only low susceptibility. In particular, the use of ciprofloxacin should be strictly avoided in urologic patients with suspicion for an ESBL-EC urinary tract infection as well as routine antibiotic prophylaxis prior to urological interventions if not explicit indicated by current international guidelines or local resistance patterns.

Comparison of the roll-plate and sonication techniques in the diagnosis of microbial ureteral stent colonisation: results of the first prospective randomised study.

BACKGROUND: Microbial ureteral stent colonisation (MUSC) is one leading risk factor for complications associated with ureteral stent placement. As MUSC remains frequently undetected by standard urine cultures, its definitive diagnosis depends on microbiological investigation of the stent. However, a standard reference laboratory technique for studying MUSC is still lacking. MATERIALS AND METHODS: A total of 271 ureteral stents removed from 199 consecutive patients were investigated. Urine samples were obtained prior to device removal. Stents were divided into four parts. Each part was separately processed by the microbiology laboratory within 6 h. Ureteral stents were randomly allocated to roll-plate or sonication, respectively, and analysed using standard microbiological techniques. Demographic and clinical data were prospectively collected using a standard case-report form. RESULTS: Overall, roll-plate showed a higher detection rate of MUSC compared with sonication (35 vs. 28 %, p < 0.05) and urine culture (35 vs. 8 %, p < 0.05). No inferiority of Maki's technique was observed even when stents were stratified according to indwelling time below or above 30 days. Compared with roll-plate, sonication commonly failed to detect Enterococcus spp., coagulase-negative staphylococci (CoNS) and Enterobacteriaceae. In addition, sonication required more hands-on time, more equipment and higher training than roll-plate in the laboratory. CONCLUSIONS: This prospective randomised study demonstrates the superiority of Maki's roll-plate technique over sonication in the diagnosis of MUSC and that urine culture is less sensitive than both methods. The higher detection rate, simplicity and cost-effectiveness render roll-plate the methodology of choice for routine clinical investigation as well as basic laboratory research.

[Fever and lymphadenopathy. Report of 4 cases of tularemia]. / Fieber und Lymphadenopathie. Bericht über 4 Tularämiefälle.

We report on 4 patients with different types of tularemia acquired in Switzerland or nearby countries. All patients presented with fever, moderate to highly elevated signs of inflammation, and local lymphadenopathy. Additionally, 3 patients did not respond to empirical antimicrobial therapy with aminopenicillins. A tick bite was identified as mode of transmission in 2 patients, while 1 patient showed a possible connection to a tick bite. The route of transmission for the fourth patient remained unknown. The diagnosis of tularemia was either based on positive serology, on a positive polymerase chain reaction (PCR) from the lymph node samples or on positive blood cultures. The treatment in adult patients was ciprofloxacin 500-750 mg twice daily orally for 3 weeks. The pediatric patient was treated with gentamicin 4 mg/kg i.v. once daily for 1 week and ciprofloxacin 15 mg/kg twice daily orally for another 2 weeks. All patients recovered completely. Due to the increasing incidence of tularemia in Switzerland, this infection should be considered in patients with fever and lymph node enlargement particularly after tick bite. We recommend treatment with ciprofloxacin orally for 14-12 days.

[Initial patient assessment of infectious diseases and diagnostic steps with fever]. / Infektiologische Erstbeurteilung und erste Abklärungsschritte bei Fieber.

The initial assessment of patients with infectious diseases is challenging because of the extremely broad differential diagnosis as well as different host pathogen interactions influenced by a different immune status. The formal initial assessment, including the present and past medical history, thorough physical examination, clinical first impressions as well as routine laboratory analyses, is the basis of every preliminary diagnosis. Specific chief complaints have to be recognized in order to narrow down the differential diagnosis. In cases of life-threatening illnesses, such as septicemia, endocarditis, bacterial meningitis and severe pneumonia, the first diagnostic and therapeutic steps should be performed in a rapid sequence: bacterial blood samples, sputum and/or liquor samples are required and the initial antibiotic therapy has to be chosen empirically as the relevant bacterial spectrum related to the suspected illness must be covered. In less urgent cases it is recommended that a multi-step diagnostic approach be carried out which takes the differential diagnosis into account and prioritizes the probabilities. In the latter situation antibiotic treatment should be delayed to diagnose the infection correctly. Importantly, atypical courses must necessitate careful and critical reassessment of the diagnosis.

Influence of environmental temperature and heatwaves on surgical site infection after hip and knee arthroplasty: a nationwide study.

BACKGROUND: Previous studies reported higher incidence of surgical site infection (SSI) after procedures performed in summer or with high temperatures. However, no study used detailed climate data to assess this risk after hip and knee arthroplasty, and no study specifically investigated the role of heatwaves. AIM: To assess the impact of higher environmental temperatures and heatwaves on SSI rates after hip and knee arthroplasty. METHODS: Data on hip and knee arthroplasty procedures performed between January 2013 and September 2019 in hospitals participating in the Swiss SSI surveillance were linked to climate data extracted from weather stations located in their vicinity. The association between temperature, heatwaves and SSI was studied using mixed effects logistic regression models fitted at the patient level. Poisson mixed models were fitted for both calendar year and month of the year to investigate the SSI incidence trajectory over time. RESULTS: We included 116,981 procedures performed in 122 hospitals. Significantly higher SSI rates were observed for procedures performed in the summertime (incidence rate ratio 1.39, 95% CI (1.20-1.60), P<0.001; reference: autumn) or in calendar months in which the mean temperature was above 20 °C (reference 5-10 °C; odds ratio 1.59, 95% CI (1.27, 1.98), P<0.001). We observed a slight but non-significant increase in the rate of SSI during heatwaves (1.44% versus 1.01%, P=0.2). CONCLUSION: SSI rates after hip and knee replacement appear to increase with higher environmental temperature. To establish whether, and to what extent, heatwaves increase the risk of SSI, studies involving geographical areas with larger variability in temperature are needed.

Pre-frail older adults show improved cognition with StayFitLonger computerized home-based training: a randomized controlled trial.

Multidomain interventions have shown tremendous potential for improving cognition in older adults. It is unclear if multidomain interventions can be delivered remotely and whether remote intervention is beneficial for older adults who are vulnerable or at risk of cognitive decline. In a 26-week multi-site, home-based, double-blind, randomized controlled trial, 120 cognitively healthy older adults (75 robust, 45 pre-frail; age range = 60-94) recruited from Switzerland, Canada, and Belgium were randomized to receive either the StayFitLonger (SFL) computerized multidomain training program or an active control intervention. Delivered on tablets, the SFL intervention combined adapted physical exercises (strength, balance, and mobility), cognitive training (divided attention, problem solving, and memory), opportunities for social and contributive interactions, and psychoeducation. The active control intervention provided basic mobilization exercises and access to video games. Cognitive outcomes were global cognition (Z-scores of attention, verbal fluency, and episodic memory for nondemented older adults; ZAVEN), memory, executive function, and processing speed. Linear mixed model analyses indicated improved performance on the ZAVEN global cognition score in the SFL group but not in the active control group. Stratified analyses by frailty status revealed improved ZAVEN global cognition and processing speed scores following SFL in the pre-frail group but not in the robust group. Overall, the study indicates that a computerized program providing a multidomain intervention at home can improve cognition in older adults. Importantly, pre-frail individuals, who are at higher risk of cognitive decline, seem to benefit more from the intervention. Trial registration: ClinicalTrials.gov, NCT037519 Registered on January 22, 2020-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04237519 .

Is floral divergence sufficient to maintain species boundaries upon secondary contact in Mediterranean food-deceptive orchids?

Analyzing the processes that determine whether species boundaries are maintained on secondary contact may shed light on the early phase of speciation. In Anacamptis morio and Anacamptis longicornu, two Mediterranean orchid sister-species, we used molecular and morphological analyses, together with estimates of pollination success and experimental crosses, to assess whether floral isolation can shelter the species' genomes from genetic admixture on secondary contact. We found substantial genetic and morphological homogenization in sympatric populations in combination with an apparent lack of postmating isolation. We further detected asymmetric introgression in the sympatric populations and an imbalance in cytotype representation, which may be due either to a difference in flowering phenology or else be a consequence of cytonuclear incompatibilities. Estimates of genetic clines for markers across sympatric zones revealed markers that significantly deviated from neutral expectations. We observed a significant correlation between spur length and reproductive success in sympatric populations, which may suggest that directional selection is the main cause of morphological differentiation in this species pair. Our results suggest that allopatric divergence has not led to the evolution of sufficient reproductive isolation to prevent genomic admixture on secondary contact in this orchid species pair.

Human metapneumovirus infection after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: The clinical characteristics of human metapneumovirus (hMPV)-associated lower respiratory tract infection (LRTI) after allogeneic hematopoietic stem cell transplantation (HSCT) is not well described. We describe the clinical course in eight HSCT recipients suffering from hMPV infection. METHODS: We prospectively included all patients with hMPV-associated LRTI after allogeneic HSCT during a period of 1 year. hMPV was diagnosed by multiplex polymerase chain reaction (PCR) from bronchoalveolar lavage (BAL). RESULTS: Eight patients with hMPV-associated LRTI were identified from 93 BAL samples. Three of the eight patients had co-infections with other pathogens. The median age of the patients was 45 years [interquartile range (IQR) 36.8-53.5], the median time posttransplant was 473 days (IQR 251-1,165), 5/8 patients had chronic graft-versus-host disease (cGvHD), and 6/8 patients received immunosuppression. Chest computed tomography (CT) scanning showed a ground-glass pattern in 7/8 patients. Seven of eight patients required hospitalization due to severe symptoms and hypoxemia. All were treated with intravenous immunoglobulin (IVIG), which was combined with oral ribavirin in six patients. The mortality rate was 12.5 % (1/8). CONCLUSIONS: hMPV-associated LRTI in allogeneic HSCT recipients are not uncommon and present with unspecific respiratory symptoms, ground-glass pattern in CT scanning, and co-infection.

Microbial ureteral stent colonization in renal transplant recipients: frequency and influence on the short-time functional outcome.

Ureteral stent insertion at the time of renal transplantation significantly decreases complications of urine leakage and obstruction, but bears an intrinsic risk of microbial colonization. Associated urinary tract infection (UTI) may pose a significant risk for graft infection and subsequent graft failure, in particular, during high-level immunosuppression in the early phase after transplantation. The aims of this prospective study were (i) to assess the frequency of microbial ureteral stent colonization (MUSC) in renal transplant recipients by sonication, (ii) to compare the diagnostic value of sonication with that of conventional urine culture (CUC), (iii) to determine biofilm forming organisms, and (iv) to investigate the influence of MUSC on the short-time functional outcome. A total of 80 ureteral stents from 78 renal transplant recipients (deceased donors n = 50, living donors n = 28) were prospectively included in the study. CUC was obtained prior to renal transplantation and at ureteral stent removal. In addition, a new stent sonication technique was performed to dislodge adherent microorganisms. CUCs were positive in 4% of patients. Sonicate-fluid culture significantly increased the yield of microbial growth to 27% (P < 0.001). Most commonly isolated microorganisms by sonication were Enterococcus species (31%), coagulase-negative staphylococci (19%), and Lactobacillus species (19%), microorganisms not commonly observed in UTIs after renal transplantation. The median glomerular filtraton rate (GFR) of the study population increases from 39 mL/min immediately after transplantation (time point A) to 50 mL/min 6 month post transplantation (time point B). In patients without MUSC, the GFR improves from 39 mL/min (A) to 48 mL/min (B) and in patients with MUSC from 39 mL/min (A) to 50 mL/min (B), respectively. In summary, MUSC in renal transplant recipients is common and remains frequently undetected by routine CUC, but colonization had no measurable effect on renal function.

[Prevention of catheter-related infections]. / Vermeidung katheterassoziierter infektionen.

Bloodstream infections due to intravascular catheterization, peritoneal catheters for dialysis, suprapubic or transurethral catheters, are one of the major sources of nosocomial infections. Therefore, the prevention of catheter-associated infections is an important issue for physicians and nursing staff working in hospitals or in outpatient settings. The risk can be minimized by diligent checking of the indications, hygienic measures, using the right materials, thorough follow-up and education of the medical and nursing staff. Thus it is possible to avoid individual suffering of patients and to reduce costs in the healthcare system.

[Prevention of catheter-related infections]. / Vermeidung katheterassoziierter Infektionen.

Bloodstream infections due to intravascular catheterization, peritoneal catheters for dialysis, suprapubic or transurethral catheters, are one of the major sources of nosocomial infections. Therefore, the prevention of catheter-associated infections is an important issue for physicians and nursing staff working in hospitals or in outpatient settings. The risk can be minimized by diligent checking of the indications, hygienic measures, using the right materials, thorough follow-up and education of the medical and nursing staff. Thus it is possible to avoid individual suffering of patients and to reduce costs in the healthcare system.

Prevalence of enterococcal groin colonization in patients undergoing cardiac interventions: challenging antimicrobial prophylaxis with cephalosporins in patients undergoing transcatheter aortic valve replacement.

BACKGROUND: Cephalosporins are recommended for prophylaxis before transcatheter aortic valve replacement (TAVR). Infective endocarditis (IE) after TAVR is caused by enterococci in up to 30% of cases, particularly early after TAVR. Enterococcal colonization in the groin has been postulated as a source of infection, not only because prophylaxis does not cover enterococci but also because most TAVR procedures are performed by transfemoral access. There are few data analysing the groin microbiome to demonstrate the presence of enterococci. AIM: To assess the prevalence of enterococci in the groins of cardiological patients receiving transfemoral interventions. METHODS: This prospective cohort study was undertaken at University Hospital Basel, Switzerland between February and August 2020. Two skin swabs were taken from the groins of consecutive patients undergoing transfemoral cardiac interventions before the administration of antibiotic prophylaxis; for each patient, swabs were taken before and after groin disinfection. Swabs were analysed in the local microbiological laboratory following validated culture methods. FINDINGS: Of 290 included patients, 245 (84.5%) underwent coronary angiography, 31 (10.7%) underwent TAVR, eight (2.8%) underwent right heart catheterization, five (1.7%) underwent closure of patent foramen ovale, and one (0.3%) underwent a MitraClip procedure. Enterococci were detected before disinfection in 48 patients, enterococci were still cultured after disinfection in three patients, and enterococci were detected after disinfection alone (i.e. not detected before disinfection) in one patient. The prevalence of enterococci was 16.6% before disinfection and 1.4% after disinfection. Patients colonized with enterococci had a significantly higher body mass index and were more likely to be diabetic than uncolonized patients. CONCLUSION: Common enterococcal colonization of the groin, coupled with frequent isolation of enterococci from patients with TAVR-associated IE, provides strong evidence that the current recommendation of antimicrobial prophylaxis with cephalosporins before TAVR should be changed to antimicrobial prophylaxis with a compound that is active against enterococci.

Matching Clostridioides difficile strains obtained from shoe soles of healthcare workers epidemiologically linked to patients and confirmed by whole-genome sequencing.

BACKGROUND: The source of transmission of Clostridioides difficile in healthcare institutions is frequently unknown. The aim of this prospective cohort study was to assess the association between strains cultured from patients and shoe soles of healthcare workers (HCWs), as already shown in the operating theatre, but not on general hospital wards in an acute-care institution. METHODS: We conducted a study at a university tertiary care centre in Switzerland. From October 2019 to July 2020, shoe soles of HCWs were cultured for C. difficile twice per shift while taking care of a patient infected with toxigenic C. difficile. Additional risk factors were assessed by interviewing involved HCWs. Patients' faecal samples were processed by routine microbiological methods. Similarity of the HCWs' and patients' strains was determined by whole-genome sequencing (WGS). RESULTS: A total of 103 HCWs exposed to 42 hospitalized patients participated in the study, providing 206 samples. Contamination of shoe soles with C. difficile was detected in 37 samples (17.8%) of HCWs taking care of patients infected with C. difficile. Overall, transmission was suspected by epidemiological link and matching strains demonstrated by WGS in 74%. CONCLUSIONS: HCWs' shoe soles were positive in 17.8% with C. difficile strains linked epidemiologically and confirmed by WGS to infected patients suggesting potential transmission by HCWs' shoe soles. This pilot study provides sufficient evidence to further evaluate this potential mode of healthcare-associated transmission of C. difficile by a larger clinical trial.

Comparison of the DiversiLab repetitive element PCR system with spa typing and pulsed-field gel electrophoresis for clonal characterization of methicillin-resistant Staphylococcus aureus.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become an increasing problem worldwide in recent decades. Molecular typing methods have been developed to identify clonality of strains and monitor spread of MRSA. We compared a new commercially available DiversiLab (DL) repetitive element PCR system with spa typing, spa clonal cluster analysis, and pulsed-field gel electrophoresis (PFGE) in terms of discriminatory power and concordance. A collection of 106 well-defined MRSA strains from our hospital was analyzed, isolated between 1994 and 2006. In addition, we analyzed 6 USA300 strains collected in our institution. DL typing separated the 106 MRSA isolates in 10 distinct clusters and 8 singleton patterns. Clustering analysis into spa clonal complexes resulted in 3 clusters: spa-CC 067/548, spa-CC 008, and spa-CC 012. The discriminatory powers (Simpson's index of diversity) were 0.982, 0.950, 0.846, and 0.757 for PFGE, spa typing, DL typing, and spa clonal clustering, respectively. DL typing and spa clonal clustering showed the highest concordance, calculated by adjusted Rand's coefficients. The 6 USA300 isolates grouped homogeneously into distinct PFGE and DL clusters, and all belonged to spa type t008 and spa-CC 008. Among the three methods, DL proved to be rapid and easy to perform. DL typing qualifies for initial screening during outbreak investigation. However, compared to PFGE and spa typing, DL typing has limited discriminatory power and therefore should be complemented by more discriminative methods in isolates that share identical DL patterns.