Emergence and dissemination of antimicrobial resistance in Escherichia coli causing bloodstream infections in Norway in 2002-17: a nationwide, longitudinal, microbial population genomic study.

BACKGROUND: The clonal diversity underpinning trends in multidrug resistant Escherichia coli causing bloodstream infections remains uncertain. We aimed to determine the contribution of individual clones to resistance over time, using large-scale genomics-based molecular epidemiology. METHODS: This was a longitudinal, E coli population, genomic, cohort study that sampled isolates from 22 512 E coli bloodstream infections included in the Norwegian surveillance programme on resistant microbes (NORM) from 2002 to 2017. 15 of 22 laboratories were able to share their isolates, and the first 22·5% of isolates from each year were requested. We used whole genome sequencing to infer the population structure (PopPUNK), and we investigated the clade composition of the dominant multidrug resistant clonal complex (CC)131 using genetic markers previously reported for sequence type (ST)131, effective population size (BEAST), and presence of determinants of antimicrobial resistance (ARIBA, PointFinder, and ResFinder databases) over time. We compared these features between the 2002-10 and 2011-17 time periods. We also compared our results with those of a longitudinal study from the UK done between 2001 and 2011. FINDINGS: Of the 3500 isolates requested from the participating laboratories, 3397 (97·1%) were received, of which 3254 (95·8%) were successfully sequenced and included in the analysis. A significant increase in the number of multidrug resistant CC131 isolates from 71 (5·6%) of 1277 in 2002-10 to 207 (10·5%) of 1977 in 2011-17 (p<0·0001), was the largest clonal expansion. CC131 was the most common clone in extended-spectrum β-lactamase (ESBL)-positive isolates (75 [58·6%] of 128) and fluoroquinolone non-susceptible isolates (148 [39·2%] of 378). Within CC131, clade A increased in prevalence from 2002, whereas the global multidrug resistant clade C2 was not observed until 2007. Multiple de-novo acquisitions of both blaCTX-M ESBL-encoding genes in clades A and C1 and gain of phenotypic fluoroquinolone non-susceptibility across the clade A phylogeny were observed. We estimated that exponential increases in the effective population sizes of clades A, C1, and C2 occurred in the mid-2000s, and in clade B a decade earlier. The rate of increase in the estimated effective population size of clade A (Ne=3147) was nearly ten-times that of C2 (Ne=345), with clade A over-represented in Norwegian CC131 isolates (75 [27·0%] of 278) compared with the UK study (8 [5·4%] of 147 isolates). INTERPRETATION: The early and sustained establishment of predominantly antimicrobial susceptible CC131 clade A isolates, relative to multidrug resistant clade C2 isolates, suggests that resistance is not necessary for clonal success. However, even in the low antibiotic use setting of Norway, resistance to important antimicrobial classes has rapidly been selected for in CC131 clade A isolates. This study shows the importance of genomic surveillance in uncovering the complex ecology underlying multidrug resistance dissemination and competition, which have implications for the design of strategies and interventions to control the spread of high-risk multidrug resistant clones. FUNDING: Trond Mohn Foundation, European Research Council, Marie Skłodowska-Curie Actions, and the Wellcome Trust

Tick-borne infections in Sogn og Fjordane, western Norway. Seroprevalence, risk factors and subjective health complaints in blood donors

Background: The tick Ixodes ricinus is involved in the transmission of a large variety of pathogens of medical and veterinary importance in Norway. The most prevalent human tickborne disease in the country is Lyme borreliosis, caused by the bacterium Borrelia burgdorferi sensu lato (s.l.). Granulocytic anaplasmosis, caused by the bacterium Anaplasma phagocytophilum, is prevalent in livestock, but only a few human cases have been published. The viral infection tick-borne encephalitis (TBE), caused by the TBE-virus (TBEV), is endemic in the southernmost parts of the country. Aims: The aims of the present thesis were to assess the frequency and risk factors of tick bites, and the seroprevalence of antibodies to B. burgdorferi s.l., A. phagocytophilum and TBEV in Sogn og Fjordane county on the western coast of Norway. In addition, we wanted to assess any association between tick bites or seropositivity for B. burgdorferi s.l. and common subjective health complaints. Finally, we wanted to compare different laboratory methods for detection of antibodies to B. burgdorferi s.l. Methods: During the first half of 2010, serum samples and questionnaires were collected from 1,213 blood donors at the four blood banks in the county. The questionnaire included questions about demographics, various life style factors, data on tick bites, and a set of questions designed to measure common and prevalent health complaints in the general population. Antibodies to B. burgdorferi s.l. were tested in Enzygnost Lyme link VlsE/IgG, Enzygnost Borreliosis IgM and Immunetics C6 Lyme ELISA kit. Sera showing positive or grey-zone reactivities in any of these tests were further tested in Euroimmun Borrelia-EUROLine-RN-AT IgG and Borrelia-EUROLine-RN-AT IgM. A random subgroup of 301 sera was examined for IgG-antibodies to A. phagocytophilum by an indirect immunofluorescence assay (IFA). All 1,213 sera were analysed for IgG-antibodies to TBEV in Serion ELISA classic TBE IgG. Results: Among the participants, 65.7% had experienced tick bites during their lifetime, and 30% had experienced tick bites during the last 12 months. Donors from the easternmost blood bank in Lærdal reported the lowest occurrence of ticks in their living area as well as the lowest number of tick bites. In the younger age-groups, males reported more bites than females. This was reversed in subjects older than 50 years of age, with females reporting more tick bites than males. Tick bites were more common among participants with the highest educational level, increased outdoor activity and among hunters and owners of domestic animals. Using the laboratory’s routine tests for detecting antibodies to B. burgdorferi s.l., Enzygnost IgG and IgM, 9.6% were positive for IgG and 8.2% for IgM. There was a positive association of IgG-seropositivity with age, and more males than females were positive for IgG (13.0% and 5.5%, respectively). IgG prevalence was higher in persons spending more time outdoors. There was a delayed age-related rise in seroprevalence in women compared to men. Subjects from the blood bank in Lærdal had the lowest prevalence of IgG. We found a substantial agreement between Enzygnost IgG and Immunetics C6 ELISA, most discrepancies were found in weakly reactive sera. IgM only was seen in 55 subjects (4.5%), of which more than half had a positive immunoblot for IgM. This pattern was seen more often in women and younger age-groups. Among the 301 blood donors tested for IgG-antibodies to A. phagocytophilum, 49 (16.2%) were positive with a titer ≥80 (range 80-1280). Among the 1,213 sera tested, six (0.5%) gave positive or grey-zone results in the ELISA test for TBEV IgG. Five of these were from persons having received vaccines that might give positive reactions in the TBE ELISA, and the last was further examined by neutralising antibodies to TBEV, with negative result. We found no association between the number of tick bites or antibodies to B. burgdorferi s.l. and subjective health complaints, reduced general function or reduced physical fitness. The number of tick bites was positively associated with good physical fitness. Conclusions: The results provide insight into the epidemiology of tick bites and tick-borne diseases in western Norway, and confirm the endemicity of Lyme borreliosis in the region. There were no indications that TBE is established as a human disease in the area, but there were serological indications that human granulocytic anaplasmosis should be considered in patients with compatible symptoms after a tick bite. The results also give insight into strengths and weaknesses of serological methods in diagnosing Lyme borreliosis, and may help to establish prudent test algorithms for this disease. There were no indications of adverse chronic health effects of tick bites or B. burgdorferi s.l. infection in this overall healthy population

Subjective health complaints are not associated with tick bites or antibodies to Borrelia burgdorferi sensu lato in blood donors in western Norway: a cross-sectional study

Background: There is controversy about chronic health consequences of tick-borne infections, especially Lyme borreliosis. This study aims to assess whether general function, physical fitness and subjective health complaints are associated with tick bites or antibodies to Borrelia burgdorferi sensu lato in blood donors. Methods: Sera from 1,213 blood donors at four different blood banks in Sogn and Fjordane county in western Norway were obtained during January to June 2010, and analysed for specific IgG and IgM antibodies. A questionnaire including questions on tick bites, subjective health complaints, general function and physical fitness was completed. Results: Tick bites had been experienced by 65.7 % of the study population. 78 (6.4 %) were positive for IgG (9.7 % in men, 2.4 % in women), and 69 (5.7 %) for IgM (6.1 % in men, 5.1 % in women), verified by immunoblot. No association between number of experienced tick bites or seropositivity for Borrelia antibodies and subjective health complaints, reduced general function or reduced physical fitness was found. Conclusion: The results do not support any association between tick bites or Borrelia antibodies and subjective health complaints in blood donors in an endemic area for Lyme borreliosis

Symptom load and general function among patients with erythema migrans: a prospective study with a 1-year follow-up after antibiotic treatment in Norwegian general practice

Objective: Promptly treated erythema migrans (EM) has good prognosis. However, some patients report persistent symptoms. Do patients with EM have more symptoms than the general population? We describe individual symptoms and general function in EM-patients at time of diagnosis and one year after treatment. Design: Prospective study with 1-year follow up after treatment. Questionnaires included a modified version of the Subjective Health Complaints Inventory, comprising three additional Lyme borreliosis (LB) related symptoms. General function was assessed using a five-point scale modified from the COOP/WONCA charts. Setting: Norwegian general practice. Subjects: A total of 188 patients were included in a randomized controlled trial comparing three antibiotic regimens for EM, of whom 139 had complete data for this study. Main outcome measures: Individual symptoms, symptom load and general function. Results: Mild symptoms were common, reported by 84.9% at baseline and by 85.6% at follow-up. At baseline, patients reported a mean of 5.4 symptoms, compared with 6.2 after one year. Severely bothersome symptoms and severely impaired general function were rare. Tiredness was the most reported symptom both at baseline and at follow-up. Palsy (other than facial) was the least reported symptom, but the only one with a significant increase. However, this was not associated to the EM. Conclusion: The symptom load was comparable to that reported in the general population. We found an increase in symptom load at follow-up that did not significantly affect general function. Implication: Monitoring patients’ symptom loads prior to treatment reduce the probability of attributing follow-up symptoms to LB.Key points Erythema migrans has a good prognosis.Patients treated for erythema migrans have a slight increase in symptom load one year after treatment. This increase does not affect general function. The levels of subjective health complaints in patients treated for erythema migrans are comparable to the background population

Seroprevalence of antibodies to tick-borne encephalitis virus and Anaplasma phagocytophilum in healthy adults from western Norway

The aim of this study was to assess the seroprevalence of antibodies to tick-borne encephalitis virus (TBEV) and Anaplasma phagocytophilum in a healthy adult population from Sogn and Fjordane county in western Norway. Sera from 1, 213 blood donors were analysed for IgG-antibodies to TBEV, and a random subgroup of 301 donors for IgG to A. phagocytophilum. In the TBEV ELISA, five (0.4%) sera were positive. These were all interpreted as “false” positives, as four had received vaccines against flaviviruses, and the remaining was negative for neutralizing antibodies to TBEV. Antibodies to A. phagocytophilum were detected by indirect immunofluorescence in 49 (16.2%) subjects (titer range 80-1280). The results indicate that TBE currently is not endemic in this part of western Norway. However, there is serological evidence of the existence of human granulocytic anaplasmosis in the population