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Background: Isolating the causative microorganism in patients with a periprosthetic joint infection (PJI) before revision surgery is critical to determine the right surgical and antibiotic strategy. A wide variety in concordance between p-SFC and intraoperative cultures is reported in the literature.

The objective was to determine the incidence of discordance and analyze risk factors for discordance between a positive preoperative synovial culture and intraoperative cultures in revision arthroplasty for PJI.

Method: An international multicenter retrospective observational cohort study was conducted including patients with septic total revision arthroplasty, between January 2020 and January 2024. Discordance and risk factors were analyzed.

Results: Discordance was 36% (n = 647). Risk factors for discordance were center specific: OR 4.22 (95% confidence interval [CI] 2.97-5.99), the presence of a sinus tract: odds ratio (OR) 1.80 (95% CI 1.22-2.66), and the hip joint: OR 1.61 (95% CI 1.12-2.30).

Conclusion: Discordance between positive preoperative synovial fluid culture and intraoperative cultures in revision arthroplasty is relatively high, center-specific, and less reliable in patients with hip arthroplasty and/or a sinus tract.

Knowledge of zoonotic links between bovine and human isolates of Staphylococcus epidermidis remains limited. The primary aim of this study was to assess the genetic relatedness of S. epidermidis isolates from bovine subclinical mastitis (SCM), bovine milk filters, healthy dairy farmers or farm personnel, and human hospital patients in Sweden, and to detect and compare genes encoding antimicrobial resistance (AMR) and virulence factors. A secondary aim was to explore the epidemiology of bovine S. epidermidis intramammary infections (IMI) by examining associations between genotypes and geographic location, persistence of IMI, severity of inflammatory response, and the persistence of S. epidermidis strains over time. A total of 283 S. epidermidis isolates were analyzed using whole genome sequencing (WGS): 128 SCM milk isolates, 55 milk filter isolates, 13 farmer/personnel isolates, and 87 human patient isolates. Sixty unique sequence types (STs) of S. epidermidis were identified. ST99, ST100, and ST570 were the most common among bovine isolates, collectively accounting for 49% (63/128) of the milk isolates and detected on multiple farms, while ST2 and ST215 were the most prevalent among human isolates. Only four STs (ST59, ST73, ST184, and ST218), representing a total of 13 isolates, were found in both bovine and human samples. Genes conferring AMR were more frequently identified in human patient isolates compared to bovine isolates. However, penicillin resistance, identified by presence of the blaZ gene, was detected in 42% of bovine S. epidermidis isolates. The average number of potential virulence factors (pVF) per isolate was 23.8 with 23.1 in milk isolates, 23.4 in milk filter isolates, 23.0 in farmer/personnel isolates, and 25.2 in human patient isolates. There was some variation in the total number of pVFs and the presence of specific pVFs or functional groups of pVFs between sample types and STs. In conclusion, the results indicate that the overlap of STs and AMR genes between human and bovine samples was minimal. However, the persistence of certain STs across multiple dairy farms suggests inter-farm transmission. This study provides new insights into the epidemiology of bovine S. epidermidis IMI, with implications for the control of these infections.

Background and purpose — Sonication fluid cultures have been proposed as a complementary diagnostic method to intraoperative tissue culture sampling for the diagnosis of periprosthetic joint infection (PJI). We evaluated whether sonication provides additional clinically relevant information in the diagnosis of PJI in hip revision.

Methods — Episodes of hip revision performed between January 2007 and December 2016 were assigned retrospectively to the European Bone and Joint Infection Society (EBJIS) definition of periprosthetic joint infection: infection unlikely, infection likely, and infection confirmed. The inclusion criteria were a minimum of 2 perioperative tissue cultures collected at the index procedure and sonication performed on a removed implant. The results of the tissue cultures were compared with the results of the implant sonication fluid cultures (SFCs).

Results — 288 hip revision episodes in 250 patients fulfilled the inclusion criteria and were analyzed. The “infection unlikely” group included 203 episodes (178 patients), the “infection likely” group included 5 episodes (5 patients), and the “infection confirmed” group included 80 episodes (67 patients). SFC delivered additional clinical information in 15/288: 6 of 203 episodes in the “infection unlikely” group, 2 of 5 episodes in the “infection likely” group, and 7 of 80 in the “infection confirmed” group. Coagulase-negative staphylococci and Staphylococcus aureus were the dominant bacterial species in both the SFC and tissue cultures.

Conclusion — In addition to tissue cultures, sonication fluid cultures optimized the microbiological yield in 15 out of 288 hip revision episodes.

Objectives: Previous research has suggested antiviral properties for lithium, including potential effectiveness against COVID-19 in vitro. This study aimed to investigate the impact of lithium and other psychotropic drugs on the risks of mortality, hospitalization, and ICU admission due to COVID-19 among individuals with bipolar disorder. The primary objective was to assess whether lithium was beneficial in COVID-19-infection in a real-world population.

Methods: Retrospective register study using data from multiple Swedish patient registers, including 39,063 individuals in Sweden with bipolar disorder and prescribed mood stabilizers. Outcomes included COVID-19-associated death, hospitalization, and ICU admission between 11 March 2020 and 10 March 2021. Multivariate logistic regression adjusted for age, sex, and somatic comorbidities was conducted.

Results: Lithium were prescribed to 44.2 % of patients, either as mono- or combination therapy; other mood stabilizers were prescribed to 55.8 %. There were no significant associations between lithium and COVID-19-associated death, hospitalization, or ICU admission. Atypical antipsychotics were associated with increased odds ratios for COVID-19-associated death (OR 1.58 [95 % CI 1.01–2.47]), hospitalization (OR 1.80 [95 % CI 1.49–2.18]), and ICU admission (OR 2.25 [95 % CI 1.33–3.80]). Benzodiazepines were associated with a significant increase in COVID-19-associated death (OR 1.54 [95 % CI 1.01–2.35]) and hospitalization OR 1.26 [95 % CI 1.03–1.53]). In an ad hoc analysis, lithium monotherapy was, however, associated with reduced hospitalizations and ICU admissions.

Conclusions: Our findings weaken the hypothesis that lithium reduces the risk of severe events associated with COVID-19 infection in bipolar disorder.

In 2010, a Cryptosporidium hominis outbreak resulted in 27,000 clinical cryptosporidiosis cases (45% of the population) in Östersund, Sweden. Long-term abdominal and joint symptoms are common following cryptosporidiosis in adults, and it can affect the development of children in low-income countries. We investigated the potential consequences for children in a high-income setting. In 2011, we prospectively surveyed 600 randomly selected children aged 0-5 years from Östersund. Cases were defined as respondents reporting new episodes of diarrhoea during the outbreak. After 10 years, respondents received a follow-up questionnaire about long-term symptoms (n = 423). We used X2 and Mann-Whitney U tests to assess between-group differences in demographics and the mean number of symptoms. Logistic regressions adjusted for sex, age, and prior issues with loose stools were used to examine associations between case status and symptoms reported at follow-up. We retrieved data on healthcare visits from patient records. In total, 121 cases and 174 non-cases responded to the follow-up questionnaire (69.7%). Cases reported 1.74 (median 1.00, range 0-14) symptoms and non-cases 1.37 (median 0.00, range 0-11) symptoms (p = 0.029). Cases were more likely to report joint symptoms (aOR 4.0, CI 1.3-12.0) and fatigue (aOR 1.9, CI 1.1-3.4), but numbers were generally low. We found no between-group differences in abdominal symptoms, healthcare utilization, or disease diagnoses. Children aged 0-5 years from high-income countries may experience long-term symptoms after cryptosporidiosis, but may not be affected to the same extent as adults or their peers living in low-income countries.

Introduction: Strategies for tuberculosis (TB) elimination in low-incidence countries involve screening recent migrants from TB-endemic regions for TB infection (TBI) and providing TB preventive treatment (TPT) to individuals with an increased risk of reactivation. This study aimed to determine TB incidence and identify reactivation risk markers in a cohort of asylum seekers in Sweden after screening.

Method: We conducted a registry-based retrospective cohort study with a three-year follow-up of asylum seekers receiving post-arrival Interferon Gamma Release Assay (IGRA) screening in three Swedish regions 2015–2019. Medical records, health-examination records, and the national TB disease registry were linked using identification numbers or probabilistic methods. The primary outcome was TB disease more than 90 days post-screening. Explanatory variables included age, sex, IGRA-result (positive/negative), TPT-initiation, and TB incidence in the country of origin. Poisson and Cox regression addressed incidence rates (IR), incidence rate ratios (IRR), and hazard ratios over a three-year follow-up.

Results: The cohort included 21 739 individuals and 70 467 person-years. Incident TB disease was recorded in 41 cases (IR 58.2/100 000 person-years). The IR for those with a positive IGRA was 321.7/100 000 person-years (n = 34). The highest risk was in persons aged under 20 with no TPT (1 279.0/100 000 person-years). Positive IGRA result, age under 20 years, and origin from TB-endemic country predicted incident TB.

Discussion: Risk markers for incident TB were similar to findings previously reported. However, the observed 0.3% annual reactivation risk found among all IGRA-positive individuals in this study was considerably lower compared to earlier findings.

Background: A multidrug-resistant lineage of Staphylococcus epidermidis named ST215 is a common cause of prosthetic joint infections and other deep surgical site infections in Northern Europe, but is not present elsewhere. The increasing resistance among S. epidermidis strains is a global concern. We used whole-genome sequencing to characterize ST215 from healthcare settings.

Results: We completed the genome of a ST215 isolate from a Swedish hospital using short and long reads, resulting in a circular 2,676,787 bp chromosome and a 2,326 bp plasmid. The new ST215 genome was placed in phylogenetic context using 1,361 finished public S. epidermidis reference genomes. We generated 10 additional short-read ST215 genomes and 11 short-read genomes of ST2, which is another common multidrug-resistant lineage at the same hospital. We studied recombination’s role in the evolution of ST2 and ST215, and found multiple recombination events averaging 30–50 kb. By comparing the results of antimicrobial susceptibility testing for 31 antimicrobial drugs with the genome content encoding antimicrobial resistance in the ST215 and ST2 isolates, we found highly similar resistance traits between the isolates, with 22 resistance genes being shared between all the ST215 and ST2 genomes. The ST215 genome contained 29 genes that were historically identified as virulence genes of S. epidermidis ST2. We established that in the nucleotide sequence stretches identified as recombination events, virulence genes were overrepresented in ST215, while antibiotic resistance genes were overrepresented in ST2.

Conclusions: This study features the extensive antibiotic resistance and virulence gene content in ST215 genomes. ST215 and ST2 lineages have similarly evolved, acquiring resistance and virulence through genomic recombination. The results highlight the threat of new multidrug-resistant S. epidermidis lineages emerging in healthcare settings.

Background: Reports at the beginning of the COVID-19 pandemic suggested differences in COVID-19-associated mortality between individuals with serious mental disorders (SMD) and the population at large.

Aim: To compare the pattern of COVID-19-associated mortality in individuals with and without SMD in Sweden over the two main pandemic years.

Methods: We compared the pattern of COVID-19-associated mortality in individuals with and without SMD in Sweden during 2020 and 2021. For SMD, we included psychotic disorder, bipolar disorder, and severe depression. The analysis was based on summary data from the Swedish Board of Health and Welfare covering the entire adult Swedish population.

Results: The overall relative risk (RR) for experiencing a COVID-19-associated death was 1.66 (CI 1.50–1.83; p < 0.001) for individuals with SMD versus individuals without SMD. The corresponding RRs were 3.25 (CI 2.84–3.71; p < 0.001) for individuals with psychotic disorder, 1.06 (CI 0.88–1.26; p = 0.54) for individuals with bipolar disorder, and 1.03 (CI 0.80–1.32; p = 0.80) for individuals with severe depression. Compared to their respective counterparts in the non-SMD group, in the psychotic disorder and severe depression group, the RR were higher in women than in men. In the bipolar disorder group, the RR was higher in men than in women. The RR of COVID-19-associated death was generally higher in younger individuals with SMD. Individuals with psychosis between 18 and 59 years had the highest RR of COVID-19-associated death with 7.25 (CI 4.54–11.59; p<0.001).

Conclusions: Individuals with SMD, and particularly those with psychotic disorders, had a higher risk of COVID-19-associated death than the general population. As this is a pattern also seen with other infections, people with SMD may be similarly vulnerable in future pandemics.

In September 2022, the Public Health Agency of Sweden observed an increase in domestic Salmonella Typhimurium cases through the Swedish electronic notification system, and an outbreak strain was identified with whole genome sequencing. Overall, 109 cases with symptom onset between 17 September and 24 November 2022 were reported from 20 of 21 Swedish regions. The median age of cases was 52 years (range 4-87 years) and 62% were female. A case-control study found cases to be associated with consumption of rocket salad (adjusted odds ratio (aOR) = 4.9; 95% confidence interval (CI): 2.4-10, p value < 0.001) and bagged mixed salad (aOR = 4.0; 95% CI: 1.9-8.1, p value < 0.001). Traceback, supported by Finnish authorities who identified the Swedish outbreak strain in a Finnish cluster during the same time period, identified rocket salad, cultivated, pre-washed and pre-packed in Sweden as the likely source of the outbreak. No microbiological analyses of rocket salad were performed. Our investigation indicates that bagged leafy greens such as rocket salad, regardless of pre-washing procedures in the production chain, may contain Salmonella and cause outbreaks, posing a health risk to consumers. We emphasise the need for primary producers of leafy greens to identify possible contamination points to prevent outbreaks.

Background: Fluoroquinolones lack approval for treatment of tularemia but have been used extensively for milder illness. Here, we evaluated fluoroquinolones for severe illness.

Methods: In an observational study, we identified case-patients with respiratory tularemia from July to November 2010 in Jämtland County, Sweden. We defined severe tularemia by hospitalization for >24 hours and severe bacteremic tularemia by Francisella tularensis subsp. holarctica growth in blood or pleural fluid. Clinical data and drug dosing were retrieved from electronic medical records. Chest images were reexamined. We used Kaplan-Meier curves to evaluate time to defervescence and hospital discharge.

Results: Among 67 case-patients (median age, 66 years; 81% males) 30-day mortality was 1.5% (1 of 67). Among 33 hospitalized persons (median age, 71 years; 82% males), 23 had nonbacteremic and 10 had bacteremic severe tularemia. Subpleural round consolidations, mediastinal lymphadenopathy, and unilateral pleural fluid were common on chest computed tomography. Among 29 hospitalized persons with complete outcome data, ciprofloxacin/levofloxacin (n = 12), ciprofloxacin/levofloxacin combinations with doxycycline and/or gentamicin (n = 11), or doxycycline as the single drug (n = 6) was used for treatment. One disease relapse occurred with doxycycline treatment. Treatment responses were rapid, with median fever duration 41.0 hours in nonbacteremic and 115.0 hours in bacteremic tularemia. Increased age-adjusted Charlson comorbidity index predicted severe bacteremic tularemia (odds ratio, 2.7 per score-point; 95% confidence interval, 1.35-5.41). A 78-year-old male with comorbidities and delayed ciprofloxacin/gentamicin treatment died.

Conclusions: Fluoroquinolone treatment is effective for severe tularemia. Subpleural round consolidations and mediastinal lymphadenopathy were typical findings on computed tomography among case-patients in this study.