Johan Ursing

Johan Ursing

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Johan Ursing has a total of 247 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Risk factors for further recurrences of Clostridioides difficile infection at the first and second recurrence: a retrospective cohort

    by Måns Stefansson, Oscar Bladh, Piotr Nowak, Lars Rombo, Magnus Hedenstierna, Johan Ursing

    Background: Recurrent Clostridioides difficile infection is most effectively treated with faecal microbiota transplantation. Swedish and European guidelines suggest faecal microbiota transplantation after a first or second recurrence, respectively. The aims of this study were to evaluate risk factors for further relapses at the first and second recurrence, related to treatment recommendations. Methods: Patients aged ≥ 18 years with two positive tests for C. difficile within eight weeks and treated at the study hospitals during 2014–2022 were eligible for inclusion. Retrospectively collected data included age, sex, treatment, and clinical characteristics for each episode. Risk factors for further recurrences at the first and second recurrence were identified using multivariable logistic regression analysis. Results: The median age in the total cohort (n = 231) was 76 (IQR 67–84) years, 52% were females and 15% were healthy without comorbidities. One recurrence only occurred in 110 patients (48%), however, no clinically significant risk factors predicting more than one recurrence were identified. Two or more recurrences occurred in 110 patients, of whom, 44 (40%) had further recurrences. Frailty (Clinical Frailty Scale ≥ 4) was significantly associated with more than two recurrences (p = 0.03). The respective median times between the first and the second recurrences were 12 and 17 days in patients with more than two recurrences compared to two recurrences only (p = 0.02). Conclusions: Patients experiencing a second recurrence of C. difficile infection who were frail and relapsed in a shorter time span after the first recurrence had a significantly increased risk of further recurrences.

  • Open Access

    Time to Staphylococcus aureus Blood Culture Positivity as a Risk Marker of Infective Endocarditis: A Retrospective Cohort Study

    by Martin Strömdahl, Karl Hagman, Karolina Hedman, Anna Westman, Magnus Hedenstierna, Johan Ursing

    Endocarditis occurs in approximately 10-15% of patients with Staphylococcus aureus bacteremia. Short time to positivity (TTP) in blood culture flasks has been linked to endocarditis in smaller studies. This study evaluated the association between TTP and endocarditis in S. aureus bacteremia in a large cohort. Adult patients with ≥1 S. aureus positive blood culture treated at a tertiary level, 500-bed hospital in Stockholm, Sweden between 2011-2021 were retrospectively identified. The primary outcome was the presence of infective endocarditis. A total of 1703 episodes of S. aureus bacteremia (23/1703 MRSA) in 1610 patients were included. Median age was 75 years (interquartile range [IQR] 63-84) and median Charlson comorbidity index was 2 (IQR 1-3). Echocardiography was performed in 1102/1703 (65%). Thirty-day mortality was 406/1703 (24%) and endocarditis was found in 154/1703 (9%). Median TTP was shorter in patients with endocarditis (9 [IQR 7-12] hours) compared to patients without endocarditis (13 [IQR 10-18] hours, p95% suggests that TTP>13 hours can be used to risk stratify patients with S. aureus bacteremia.


  • Open Access

    Safety and tolerability of frozen, capsulized autologous faecal microbiota transplantation. A randomized double blinded phase I clinical trial

    by Måns Stefansson, Oscar Bladh, Ola Flink, Otto Skolling, Hans-Peter Ekre, Lars Rombo, Lars Engstrand, Johan Ursing

    Background: Faecal microbiota transplantation (FMT) is recommended treatment for recurrent Clostridioides difficile infection and is studied as a potential modifier of other gastrointestinal and systemic disorders. Autologous FMT limits the potential risks of donor transplant material and enables prophylactic treatment. Capsulized FMT is convenient and accessible, but safety data are lacking. Aims: To describe safety and tolerability of capsules containing autologous FMT, compared to placebo, in healthy volunteers treated with antibiotics. Method: Healthy volunteers without antibiotic exposure during the past three months, that had a negative Clostridioides difficile stool sample, were recruited. Study persons donated faeces for production of capsules containing autologous microbiota. They were then given Clindamycin for seven days to disrupt the intestinal microbiota, which was followed by a two-day washout. Study persons were then randomized (1:1) to unsupervised treatment with autologous faecal matter or placebo, with two capsules twice daily for five days. A standardized questionnaire about side effects and tolerability, daily until day 28, and on days 60 and 180, was completed. Results: Twenty-four study persons were included, all completed the treatment. One person from the placebo and FMT groups each, were lost to follow up from days 21 and 60, respectively. No study person experienced serious side effects, but severe fatigue was reported during the antibiotic period (n = 2). Reported side effects were mild to moderate and there were no significant differences between the groups. Reported general and intestinal health improved significantly and similarly in both groups after the antibiotic treatment. Time to normalized intestinal habits were 17 and 19 days from study start in the placebo group and the FMT group, respectively (p = 0.8). Conclusion: Capsulized frozen autologous faecal microbiota transplantation was safe and well tolerated but did not affect time to normalized intestinal habits compared to placebo. Trial registration: EudraCT 2017-002418-30.


  • Open Access

    Effects of remdesivir on SARS-CoV-2 viral dynamics and mortality in viraemic patients hospitalized for COVID-19

    by Karl Hagman, Magnus Hedenstierna, Jacob Widaeus, Emelie Arvidsson, Berit Hammas, Lena Grillner, Jan Jakobsson, Patrik Gille-Johnson, Johan Ursing

    Studies on the antiviral effects of remdesivir have shown conflicting results. SARS-CoV-2 viraemia could identify patients in whom antiviral treatment may be particularly beneficial. To investigate antiviral effects and clinical outcomes of remdesivir treatment in viraemic patients. Viraemic patients hospitalized for COVID-19 with ratio of arterial oxygen partial pressure to fractional inspired oxygen of ≤300, symptom duration ≤10 days, and estimated glomerular filtration rate ≥30 mL/min were included in a cohort. The rate of serum viral clearance and serum viral load decline, 60 day mortality and in-hospital outcomes were estimated. A subgroup analysis including patients with symptom duration ≤7 days was performed. A total of 318 viraemic patients were included. Thirty-three percent (105/318) received remdesivir. The rate of serum viral clearance [subhazard risk ratio (SHR) 1.4 (95% CI 0.9–2.0), P = 0.11] and serum viral load decline (P = 0.11) were not significantly different between remdesivir-treated patients and controls. However, the rate of serum viral clearance was non-significantly higher [SHR 1.6 (95% CI 1.0–2.7), P = 0.051] and the viral load decline was faster (P = 0.03) in remdesivir-treated patients with symptom duration ≤7 days at admission. The 60 day mortality [HR 1.0 (95% CI 0.6–1.8), P = 0.97] and adverse in-hospital outcomes [OR 1.4 (95% CI 0.8–2.4), P = 0.31] were not significantly different between remdesivir-treated patients and controls. Remdesivir treatment did not significantly change the duration of SARS-CoV-2 viraemia, decline of serum viral load, 60 day mortality or in-hospital adverse outcomes in patients with ≤10 days of symptoms at admission. Remdesivir appeared to reduce the duration of viraemia in a subgroup of patients with ≤7 days of symptoms at admission.


  • Open Access

    Correlation of SARS-CoV-2 Nasopharyngeal CT Values With Viremia and Mortality in Adults Hospitalized With COVID-19

    by Karl Hagman, Magnus Hedenstierna, Jacob Widaeus, Emelie Arvidsson, Berit Hammas, Lena Grillner, Jan Jakobsson, Patrik Gille-Johnson, Johan Ursing

    Background: Both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viremia and nasopharyngeal viral load have been suggested to be predictors of unfavorable outcome in coronavirus disease 2019 (COVID-19). This study aimed to investigate whether nasopharyngeal viral load is correlated with viremia and unfavorable outcome.Methods: The presence of SARS-CoV-2 RNA was determined in paired nasopharyngeal and serum samples collected at admission from patients hospitalized for COVID-19. Standardized cycle threshold values (CT values) were used as an indicator of viral load. An adjusted logistic regression was used to estimate the risk of viremia at different nasopharyngeal CT values. A Cox regression was used to estimate the risk of 60-day mortality.Results: A total of 688 patients were included. Viremia at admission was detected in 63% (146/230), 46% (105/226), and 31% (73/232) of patients with low, intermediate, and high nasopharyngeal CT values. The adjusted odds ratios of being viremic were 4.4 (95% CI, 2.9–6.8) and 2.0 (95% CI, 1.4–3.0) for patients with low and intermediate CT values, compared with high CT values. The 60-day mortality rate was 37% (84/230), 15% (36/226), and 10% (23/232) for patients with low, intermediate, and high nasopharyngeal CT values at admission, respectively. Adjusted hazard ratios were 2.6 (95% CI, 1.6–4.2) and 1.4 (95% CI, 0.8–2.4) for patients with low and intermediate CT values compared with high CT values.Conclusions: There was a dose-dependent correlation between nasopharyngeal CT values and viremia at admission for COVID-19. Moreover, there was an increased risk of 60-day mortality for patients with low, compared with high, nasopharyngeal CT values.


  • Open Access

    Chloroquine-susceptible and -resistantPlasmodium falciparumstrains survive high chloroquine concentrations by becoming dormant but are eliminated by prolonged exposure

    by Johan Ursing, Rasmus Johns, Berit Aydin-Schmidt, Carla Calçada, Poul-Erik Kofoed, Najia Karim Ghanchi, Maria Isabel Veiga, Lars Rombo

    Plasmodium falciparum strains that are resistant to standard-dose chloroquine can be treated by higher chloroquine concentrations maintained for a longer time in vivo. To determine the relative importance of chloroquine concentrations versus exposure time for elimination of chloroquine-susceptible and -resistant P. falciparum in vitro. Chloroquine-susceptible (3D7) and -resistant (FCR3) strains were exposed in vitro to 1, 2, 4, 8, 16 or 32 times their respective 90% inhibitory chloroquine concentrations for 3, 5, 7 or 14 days and then followed until recrudescence, or not, by 42 days after the end of exposure. Exposure to chloroquine appeared to eliminate susceptible and resistant parasites, leaving small pyknotic apparently dead parasites. Chloroquine-susceptible and -resistant parasites recrudesced after 3 and 5 days of chloroquine exposure. Recrudescence occurred in one out of four 7 day exposure series but not after 14 days exposure. The median time to recrudescence was 13 to 28 days with a range of 8 to 41 days after the end of exposure. Time to recrudescence after the end of exposure increased with duration of exposure for susceptible and resistant strains (P < 0.001). Time to recrudescence did not correlate with concentrations greater than 1× IC90. Chloroquine-susceptible and -resistant P. falciparum probably become dormant. Elimination of dormant parasites is primarily dependent upon the duration of chloroquine exposure. Exposure to effective drug concentrations for 7 days eliminates most parasites in vitro. The results support in vivo data indicating that elimination of chloroquine-resistant P. falciparum correlates with Day 7 chloroquine concentrations.


  • Open Access

    Prevalence of diarrhoeal pathogens among children under five years of age with and without diarrhoea in Guinea-Bissau

    by Sointu Mero, Suvi Timonen, Tinja Lääveri, Sandra Løfberg, Juha Kirveskari, Johan Ursing, Lars Rombo, Poul-Erik Kofoed, Anu Kantele

    Background: Childhood diarrhoea, a major cause of morbidity and mortality in low-income regions, remains scarcely studied in many countries, such as Guinea-Bissau. Stool sample drying enables later qPCR analyses of pathogens without concern about electricity shortages. Methods: Dried stool samples of children under five years treated at the Bandim Health Centre in Bissau, Guinea-Bissau were screened by qPCR for nine enteric bacteria, five viruses, and four parasites. The findings of children having and not having diarrhoea were compared in age groups 0–11 and 12–59 months. Results: Of the 429 children– 228 with and 201 without diarrhoea– 96.9% and 93.5% had bacterial, 62.7% and 44.3% viral, and 52.6% and 48.3% parasitic pathogen findings, respectively. Enteroaggregarive Escherichia coli (EAEC; 60.5% versus 66.7%), enteropathogenic E. coli (EPEC; 61.4% versus 62.7%), Campylobacter (53.2% versus 51.8%), and enterotoxigenic E. coli (ETEC; 54.4% versus 44.3%) were the most common bacterial pathogens. Diarrhoea was associated with enteroinvasive E. coli (EIEC)/Shigella (63.3%), ETEC (54.4%), astrovirus (75.0%), norovirus GII (72.6%) and Cryptosporidium (71.2%). The only pathogen associated with severe diarrhoea was EIEC/Shigella (pShigella, Giardia duodenalis and Dientamoeba fragilis among the older children. Conclusions: Stool pathogens proved common among all the children regardless of them having diarrhoea or not.


  • Open Access

    Stable high frequencies of sulfadoxine–pyrimethamine resistance associated mutations and absence of K13 mutations in Plasmodium falciparum 3 and 4 years after the introduction of artesunate plus sulfadoxine–pyrimethamine in Ujjain, Madhya Pradesh, India

    by Ashish Pathak, Andreas Mårtensson, Sudhir Gawariker, Ashish Sharma, Vishal Diwan, Manju Purohit, Johan Ursing

    Background: Artesunate plus sulfadoxine–pyrimethamine (ASP) is first-line treatment for uncomplicated Plasmodium falciparum malaria in most of India, except for six North-eastern provinces where treatment failure rates were high. In Ujjain, central India, the frequency of mutations associated with increased drug tolerance, but not overt resistance to sulfadoxine and pyrimethamine were 9% and > 80%, respectively, in 2009 and 2010, just prior to the introduction of ASP. The frequency of drug resistance associated mutations in Ujjain in 2015–2016 after 3–4 years of ASP use, are reported. Methods: Blood samples from patients with P. falciparum mono-infection verified by microscopy were collected on filter-paper at all nine major pathology laboratories in Ujjain city. Codons pfdhfr 16–185, pfdhps 436–632 and K13 407–689 were identified by sequencing. Pfcrt K76T and pfmdr1 N86Y were identified by restriction fragment length polymorphism. Results: Sulfadoxine–pyrimethamine resistance-associated pfdhfr 108 N and 59R alleles were found in 100/104 (96%) and 87/91 (96%) samples, respectively. Pfdhps 437G was found in 10/105 (10%) samples. Double mutant pfdhfr 59R + 108 N were found in 75/81 (93%) samples. Triple mutant pfdhfr 59R + 108 N and pfdhps 437G were found in 6/78 (8%) samples. Chloroquine-resistance-associated pfcrt 76T was found in 102/102 (100%). Pfmdr1 N86 and 86Y were identified in 83/115 (72%) and 32/115 (28%) samples, respectively. Conclusion: The frequency of P. falciparum with reduced susceptibility to sulfadoxine–pyrimethamine remained high, but did not appear to have increased significantly since the introduction of ASP. No polymorphisms in K13 associated with decreased artemisinin susceptibility were found. ASP probably remained effective, supporting continued ASP use.


  • Open Access

    Stable high frequencies of sulfadoxine-pyrimethamine resistance associated mutations and absence of K13 mutations in Plasmodium falciparum 3 and 4 years after the introduction of artesunate plus sulfadoxine-pyrimethamine in Ujjain, Madhya Pradesh, India

    by Ashish Pathak, Andreas Mårtensson, Sudhir Gawariker, Ashish Sharma, Vishal Diwan, Manju Purohit, Johan Ursing

    Background Artesunate plus sulfadoxine-pyrimethamine (ASP) is first-line treatment for uncomplicated Plasmodium falciparum malaria in most of India, except for six North-eastern provinces where treatment failure rates were high. In Ujjain, central India, the frequency of mutations associated with increased drug tolerance, but not overt resistance to sulfadoxine and pyrimethamine were 9% and >80%, respectively, in 2009 and 2010, just prior to the introduction of ASP. The frequency of drug resistance associated mutations in Ujjain in 2015-2016 after 3-4 years of ASP use, are reported.Methods Blood samples from patients with P. falciparum mono-infection verified by microscopy were collected on filter-paper at all nine major pathology laboratories in Ujjain city. Codons pfdhfr 16-185, pfdhps 436-632 and K13 407-689 were identified by sequencing. Pfcrt K76T and pfmdr1 N86Y were identified by restriction fragment length polymorphism. Results Sulfadoxine-pyrimethamine resistance-associated pfdhfr 108N and 59R alleles were found in 100/104 (96%) and 87/91 (96%) samples, respectively. Pfdhps 437G was found in 10/105 (10%) samples. Double mutant pfdhfr 59R+108N were found in 75/81 (93%) samples. Triple mutant pfdhfr 59R + 108N and pfdhps 437G were found in 6/78 (8%) samples. Chloroquine-resistance-associated pfcrt 76T was found in 102/102 (100%). Pfmdr1 N86 and 86Y were identified in 83/115 (72%) and 32/115 (28%) samples, respectively. Conclusion The frequency of P. falciparum with reduced susceptibility to sulfadoxine-pyrimethamine remained high, but did not appear to have increased significantly since the introduction of ASP. No polymorphisms in K13 associated with decreased artemisinin susceptibility were found. ASP probably remained effective, supporting continued ASP use.