Whole genome sequencing reveals two genetically distinct MRSA outbreaks among people who inject drugs and homeless people in Copenhagen.

Whole genome sequencing (WGS) has greatly improved the detection of methicillin-resistant Staphylococcus aureus (MRSA) transmission between people. We describe the transmission of two unique MRSA clones among homeless people in Copenhagen using WGS and core genome MLST (cgMLST). In 2014, an accumulation of MRSA bacteremia cases among homeless people admitted to our hospital was recognized, all having the rare MRSA spa t5147/ST88. The European Typology of Homelessness and Housing Exclusion (ETHOS) categories revealed that people who inject drugs (PWID) frequently visiting the milieu but living in private accommodation accounted for most cases. Hoping to terminate the transmission, 161 homeless people were MRSA screened in 2015, but no additional cases were found. From 2009 to 2018, 60 patients with genomically related t5147/ST88 isolates were found, of these 70% were confirmed to come from the homeless setting and 17% had bacteremia. From 2017 to 2020, cgMLST revealed a smaller MRSA outbreak including 13 PWID with a completely different clone, t1476/ST8, of which 15% had bacteremia. Our study confirms that WGS and cgMLST is excellent to reveal MRSA outbreaks. The ETHOS categorization can be useful to find the primary source of spread in the homeless community.

Synbiotic Intervention with Lactobacilli, Bifidobacteria, and Inulin in Healthy Volunteers Increases the Abundance of Bifidobacteria but Does Not Alter Microbial Diversity.

Synbiotics combine probiotics and prebiotics and are being investigated for potential health benefits. In this single-group-design trial, we analyzed changes in the gut microbiome, stool quality, and gastrointestinal well-being in 15 healthy volunteers after a synbiotic intervention comprising Lacticaseibacillus rhamnosus (LGG), Lactobacillus acidophilus (LA-5), Lacticaseibacillus paracasei subsp. paracasei (L. CASEI 431), and Bifidobacterium animalis subsp. lactis BB-12 and 20 g of chicory-derived inulin powder consumed daily for 4 weeks. Fecal samples were collected at baseline and at completion of the intervention, and all participants completed a fecal diary based on the Bristol Stool Scale and recorded their gastrointestinal well-being. No adverse effects were observed after consumption of the synbiotic product, and stool consistency and frequency remained almost unchanged during the trial. Microbiome analysis of the fecal samples was achieved using shotgun sequencing followed by taxonomic profiling. No changes in alpha and beta diversity were seen after the intervention. Greater relative abundances of Bifidobacteriaceae were observed in 12 subjects, with indigenous bifidobacteria species constituting the main increase. All four probiotic organisms increased in abundance, and L. rhamnosus, B. animalis, and L. acidophilus were differentially abundant, compared to baseline. Comparison of the fecal strains to the B. animalis subsp. lactis BB-12 reference genome and the sequenced symbiotic product revealed only a few single-nucleotide polymorphisms differentiating the probiotic B. animalis subsp. lactis BB-12 from the fecal strains identified, indicating that this probiotic strain was detectable after the intervention. IMPORTANCE The effects of probiotics/synbiotics are seldom investigated in healthy volunteers; therefore, this study is important, especially considering the safety aspects of multiple probiotics together with prebiotic fiber in consumption by humans. The study explores at the potential of a synbiotic intervention with lactobacilli, bifidobacteria, and inulin in healthy volunteers and tracks the ingested probiotic strain B. animalis subsp. lactis.

Estimated Roles of the Carrier and the Bacterial Strain When Methicillin-Resistant Staphylococcus aureus Decolonization Fails: a Case-Control Study.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common bacterial pathogen that frequently colonizes healthy individuals, with potential to cause invasive infection. In Denmark, to keep the prevalence low, MRSA carriers are recommended to undergo decolonization treatments, but achieving decolonization is challenging. Knowledge about the factors contributing to decolonization is scarce. We aimed to identify bacterial genome and clinical factors influencing MRSA decolonization. We identified all new MRSA patients above 2 years of age within the Hvidovre catchment area, Copenhagen, Denmark, in 2017 and 2018. Carriers were defined as chronic carriers (cases) if they were MRSA positive after two or more treatments and as nonchronic carriers (controls) if they were MRSA free after the first or second treatment. Using whole-genome sequencing (WGS), we constructed a pangenome of bacterial strains. With the incorporation of bacterial genome and clinical patient data, machine learning and multivariate analyses were performed to determine the factors associated with decolonization. A total of 477 MRSA carriers were included. An age of ≥13 years was significantly associated with nonchronic carriage. We identified 278 bacterial genetic features that were statistically significantly associated with chronic carriage (P < 0.05 by Fisher's exact test). Chronic MRSA carriage was predicted with 68% accuracy using a combination of bacterial genome data and patient clinical data. Decolonization success is multifactorial. Apart from the 68% predicted accuracy found in this study, we estimate that the remaining 32% is a result of host factors and microbiome composition. IMPORTANCE Carriage of methicillin-resistant Staphylococcus aureus (MRSA) and other multiresistant bacteria is a prerequisite for infection and transmission. Successful decolonization treatment removes these risks. We aimed to identify bacterial genome and host clinical factors that influence MRSA decolonization to estimate the roles of the carrier and the bacterial strain, respectively, when decolonization fails. The long-term goal, beyond this study, is to optimize decolonization success, minimize MRSA transmission, and, ultimately, improve the quality of life of MRSA carriers.

A randomized, placebo-controlled, double-blinded trial of MRSA throat carriage treatment, with either standard decolonization alone or in combination with oral clindamycin.

BACKGROUND: Staphylococcus aureus is a frequent colonizer of the human skin and mucous membranes but can also cause a variety of serious infections. Antimicrobial resistance is an increasing worldwide challenge and is mainly driven by an overuse of antimicrobials. To avoid the spread of methicillin-resistant Staphylococcus aureus (MRSA) in Denmark, the Danish Health Authority recommends decolonization treatment of MRSA carriers and their household contacts. Standard decolonization treatment includes chlorhexidine body wash and mupirocin nasal ointment, especially throat carriage is difficult to treat. The broad-spectrum antibiotic, clindamycin, is often added to the decolonization treatment, but there is currently low scientific evidence for this treatment. AIM: To investigate whether the addition of clindamycin to the standard decolonization treatment increases decolonization success in MRSA throat carriers. METHODS: A randomized, placebo-controlled, double-blinded trial, including patients ≥ 18 years, who tested MRSA positive in the throat after completing one standard decolonization treatment. All carriers included in the trial receive standard decolonization treatment and are randomized to treatment with either placebo or clindamycin capsules for 10 days. We plan to include 40 participants in each of the two treatment arms. DISCUSSION: Due to the lack of consistent scientific evidence of clindamycin's effect in MRSA decolonization and the worldwide urgent need to reduce the use of antibiotics, we judged that a 30% increase in the decolonization success rate in carriers treated with clindamycin is appropriate to justify prescribing clindamycin as part of the decolonization treatment of asymptomatic MRSA carriers. TRIAL REGISTRATION: EudraCT number 2019-002631-29.

No Effect of Lactobacillus rhamnosus GG on Eradication of Colonization by Vancomycin-Resistant Enterococcus faecium or Microbiome Diversity in Hospitalized Adult Patients.

The purpose of this trial was to evaluate the efficacy of a 4-week supplementation of Lactobacillus rhamnosus GG (LGG) in eliminating the gastrointestinal carrier state of vancomycin-resistant Enterococcus faecium (VREfm) in hospitalized adults. The primary outcome of the study was the number of patients with cleared VREfm colonization after the 4-week intervention. Secondary outcomes were clearance of VREfm colonization at weeks 8, 16, and 24, number of VREfm infections (isolated from nonintestinal foci), and changes in fecal microbiome diversity after the intervention. The trial was a multicenter, randomized, double-blind, placebo-controlled trial in hospitalized adult VREfm carriers. Patients were enrolled and randomized to receive 60 billion CFU of LGG daily or placebo for 4 weeks. For a subgroup of patients, rectal swabs for VREfm were collected also at 8, 16, and 24 weeks and analyzed using shotgun metagenomics. Patients ingesting a minimum of 50% of the probiotic during the 4-week intervention were included in subsequent outcome analyses (48 of 81 patients). Twelve of 21 patients in the LGG group (57%) compared to 15 of 27 patients in the placebo group (56%) cleared their VREfm carriage. Eighteen patients completed the entire 24-week intervention with the same minimum compliancy. Of these, almost 90% in both groups cleared their VREfm carriage. We found a statistically significant difference between VREfm clearers and nonclearers regarding metronidazole and vancomycin usage as well as length of hospitalization after inclusion. The microbiome analyses revealed no significant difference in alpha diversity between the LGG and the placebo group. Beta diversity differed between the groups and the different time points. This study did not show an effect of LGG in eradication of VREfm after a 4-week intervention. IMPORTANCE Whereas other studies exploring the effect of L. rhamnosus in clearing VREfm from the intestine included children and adults, with a wider age range, our study consisted of a geriatric patient cohort. The natural clearance of VREfm in this study was almost 60% after 4 weeks, thus much higher than described previously. Also, this study characterizes the microbiome of VREfm patients in detail. This article showed no effect of the probiotic L. rhamnosus in clearing VREfm from the intestine of patients.

Decrease in All-Cause 30-Day Mortality after Bacteraemia over a 15-Year Period: A Population-Based Cohort Study in Denmark in 2000-2014.

INTRODUCTION: Bacteraemia is a frequent infectious condition that strongly affects morbidity and mortality. The incidence is increasing worldwide. This study explores all-cause 30-day mortality after bacteraemia in two out of Denmark's five healthcare regions with approximately 2.4 million inhabitants. METHODS: Clinically significant bacteraemia episodes (n = 55,257) were identified from a geographically well-defined background population between 2000 and 2014, drawing on population-based data regarding bacterial species and vital status. All-cause 30-day mortality was assessed in relation to bacteraemia episodes, number of patients with analysed blood cultures and the background population. RESULTS: We observed a decreasing trend of all-cause 30-day mortality between 2000 and 2014, both in relation to the number of bacteraemia episodes and the background population. Mortality decreased from 22.7% of the bacteraemia episodes in 2000 to 17.4% in 2014 (annual IRR [95% CI]: 0.983 [0.979-0.987]). In relation to the background population, there were 41 deaths per 100,000 inhabitants in 2000, decreasing to 39 in 2014 (annual IRR [95% CI]: 0.988 [0.982-0.993]). Numbers of inhabitants, bacteraemia episodes, and analysed persons having BCs increased during the period. CONCLUSIONS: All-cause 30-day mortality in patients with bacteraemia decreased significantly over a 15-year period.

Prevalence of MRSA nasal carriage among pregnant women in Copenhagen.

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) frequently causes outbreaks in neonatal intensive care units (NICUs). It is believed that MRSA predominantly enters the NICU with MRSA colonized parents. In Denmark, 27 MRSA NICU outbreaks have been registered between 2008 and 2019. AIM: The aim of this study was to determine the prevalence of MRSA nasal carriage in pregnant women in Copenhagen and to clarify if MRSA screening during pregnancy could add to the prevention of NICU outbreaks. METHODS: All pregnant women 18 years or older were offered MRSA nasal screening at their first midwife visit between 13 and 20 weeks of gestation. RESULTS: 1778 pregnant women were included, two (0.11%) carried MRSA in the nose. CONCLUSION: Infants of the two MRSA positive women were not admitted to a NICU and therefore the screening had no impact on NICU outbreaks. The low prevalence of MRSA found in this study does not justify MRSA screening of all pregnant women in Denmark.

All-cause Mortality Due to Bacteremia during a 60-Day Non-Physician Healthcare Worker Strike.

This study explored all-cause mortality of bacteremia diagnosed during a 60-day non-physician healthcare worker strike in 2008. A significant change, with 5.0% (95% confidence interval [CI] 1.2-8.7%, P < .01) absolute risk increase, was seen in 90-day mortality during the strike (n = 598) compared with the rest of the study period 2000-2015 (n = 75 647).

Point-of-care tests for influenza A and B viruses and RSV in emergency departments - indications, impact on patient management and possible gains by syndromic respiratory testing, Capital Region, Denmark, 2018.

BackgroundPoint-of-care tests (POCT) for influenza A and B viruses and respiratory syncytial virus (RSV) were implemented in emergency departments of all hospitals in the Capital Region of Denmark in 2018.AimTo establish whether POC testing for influenza viruses or RSV is based on a valid respiratory symptom indication, whether changes in patient management based on a positive result are safe and whether syndromic POC testing may benefit patients with influenza or RSV.MethodsSamples from 180 children (< 18 years) and 375 adults tested using POCT between February and July 2018 were retested for 26 respiratory pathogens. Diagnosis, indication for POC testing, hospitalisation time, antimicrobial therapy and readmission or death within one month of testing were obtained from patient records.ResultsA valid indication for POC testing was established in 168 (93.3%) of children and 334 (89.1%) of adults. A positive POCT result significantly reduced antibiotic prescription and median hospitalisation time by 44.3 hours for adults and 14.2 hours for children, and significantly increased antiviral treatment in adults. Risk of readmission or death was not significantly altered by a positive result. Testing for 26 respiratory pathogens established that risk of coinfection is lower with increasing age and that POCT for adults should be restricted to the influenza and RSV season.ConclusionPositive POCT resulted in changed patient management for both children and adults, and was deemed safe. POCT for additional pathogens may be beneficial in children below 5 years of age and outside the influenza and RSV season.