Changes in prevalence of Mycoplasma genitalium macrolide and fluoroquinolone resistance: notes from a 13-year retrospective survey in Dalarna County, Sweden.

OBJECTIVE: Macrolide and fluoroquinolone resistance in Mycoplasma genitalium (MG) is of emerging global concern. Compared with neighbouring countries such as Denmark, Sweden has had lower rates of macrolide resistance while fluoroquinolone resistance rates are less well documented. This study retrospectively examined macrolide, fluoroquinolone and multidrug resistance rates from Dalarna County, Sweden over a 13-year period. METHODS: MG-positive samples from 2006 to 2018 from patients examined at the Department of Venereology, Central Hospital, Falun, Sweden were tested by sequencing for macrolide resistance mutations (MRM) and fluoroquinolone resistance-associated mutations (QRAM) in the parC and gyrA subunit regions. A subset of these samples from 2006 to 2011 have been reported on previously, although only for MRM. RESULTS: Of 874 samples, 98 (11.2%, 95% CI 9.1% to 13.6%) had mutations associated with resistance to macrolides and 19 of 828 (2.3%, 95% CI 8.9% to 23.1%) to quinolones. Mutations associated with resistance to both drugs were detected in 5 of 828 (0.6%, 95% CI 0.1% to 1.4%) samples overall. A significant positive linear trend (p=0.004) for an increase in the rate of macrolide resistance was observed (from 0% in 2006 to 31% in 2018) while the increase in QRAM from 0% in 2006 to 12.3% in 2018 was not statistically significant. CONCLUSIONS: Despite a decrease in macrolide and fluoroquinolone consumption in Sweden, there was an overall increase in MG macrolide, fluoroquinolone and dual resistance from 2006 to 2018, although the difference in fluoroquinolone resistance rates was not statistically significant. In order to maintain comparably low resistance rates, resistance-guided therapy for MG infections will be crucial.

Changes in testing and incidence of Chlamydia trachomatis and Neisseria gonorrhoeae - the possible impact of the COVID-19 pandemic in the three Scandinavian countries.

BACKGROUND: This study aimed to investigate what impact the COVID-19 pandemic and its associated restrictions had on Chlamydia trachomatis and Neisseria gonorrhoeae infections in Sweden, Denmark and Norway, countries with very different governmental strategies for handling this pandemic. METHODS: Retrospective analysis of data collected via requests to Swedish regions and to health authorities in Denmark and Norway. The data were collected for the years 2018-2020 and the data from Sweden were more detailed. RESULTS: When the pandemic restrictions were installed in 2020, the number of reported chlamydia cases decreased. The decline was most pronounced in Norway 10.8% (2019: n = 28,446; 2020: n = 25,444) while it was only 3.1% in Denmark (2019: n = 35,688; 2020: n = 34,689) and 4.3% in Sweden (2019: n = 34,726; 2020: n = 33,339). Nucleic acid amplifications tests for chlamydia decreased in Sweden (10%) and Norway (18%) in 2020 compared to 2019, while in Denmark a 21% decrease was noted in April 2020 but thereafter increased to a higher level than 2019. The number of reported gonorrhoea cases decreased in Sweden (17%) and in Norway (39%) in 2020 compared to 2019, while a 21% increase was noted in Denmark. CONCLUSIONS: Pandemic restrictions had an impact on the number of reported chlamydia infections in all three countries, but only temporarily and did not seem to be correlated to the restriction levels. The number of reported gonorrhoea infections in Sweden and Norway significantly decreased but not in Denmark. Pandemic restrictions appear to have had a limited effect on the spread of chlamydia and gonorrhoea.

Ten years transmission of the new variant of Chlamydia trachomatis in Sweden: prevalence of infections and associated complications.

OBJECTIVES: In 2006, a new variant of Chlamydia trachomatis (nvCT) was discovered in Sweden. It has a deletion in the plasmid resulting in failed detection by the single target systems from Abbott and Roche used at that time, whereas the third system used, from Becton Dickinson (BD), detects nvCT. The proportion of nvCT was initially up to 65% in counties using Abbott/Roche systems. This study analysed the proportion of nvCT from 2007 to 2015 in four selected counties and its impact on chlamydia-associated complications. METHODS: C. trachomatis-positive specimens collected from 2007 to 2015 were analysed by a specific PCR to identify nvCT cases. Genotyping was performed by multilocus sequence typing (MLST) and ompA sequencing. Ectopic pregnancy and pelvic inflammatory disease records were extracted from the national registers. RESULTS: In total, 5101 C. trachomatis-positive samples were analysed. The nvCT proportion significantly decreased in the two counties using Roche systems, from 56% in 2007 to 6.5% in 2015 (p<0.001). In the two counties using BD systems, a decrease was also seen, from 19% in 2007 to 5.2% in 2015 (p<0.001). Fifteen nvCT cases from 2015 and 102 cases from 2006 to 2009 had identical MLST profiles. Counties using Roche/Abbott systems showed higher mean rates of ectopic pregnancy and pelvic inflammatory disease compared with counties using BD systems. CONCLUSIONS: The nvCT proportion has decreased in all counties and converged to a low prevalence irrespective of previous rates. Genotyping showed that nvCT is clonal and genetically stable. Failing detection only marginally affected complication rates.

Serologic and Molecular Prevalence of Rickettsia helvetica and Anaplasma phagocytophilum in Wild Cervids and Domestic Mammals in the Central Parts of Sweden.

Both Rickettsia helvetica and Anaplasma phagocytophilum are common in Ixodes ricinus ticks in Sweden. Knowledge is limited regarding different animal species' competence to act as reservoirs for these organism. For this reason, blood samples were collected from wild cervids (roe deer, moose) and domestic mammals (horse, cat, dog) in central Sweden, and sera were tested using immunofluorescence assay to detect antibodies against spotted fever rickettsiae using Rickettsia helvetica as antigen. Sera with a titer ≥1:64 were considered as positive, and 23.1% (104/450) of the animals scored positive. The prevalence of seropositivity was 21.5% (23/107) in roe deer, 23.3% (21/90) in moose, 36.5% (23/63) in horses, 22.1% (19/90) in cats, and 17.0% (17/100) in dogs. PCR analysis of 113 spleen samples from moose and sheep from the corresponding areas were all negative for rickettsial DNA. In roe deer, 85% (91/107) also tested seropositive for A. phagocytophilum with a titer cutoff of 1:128. The findings indicate that the surveyed animal species are commonly exposed to rickettsiae and roe deer also to A. phagocytophilum.

Life cycle, growth characteristics and host cell response of Rickettsia helvetica in a Vero cell line.

Rickettsia helvetica, a spotted fever rickettsia and emerging pathogen with Ixodes ricinus ticks as the main vector, is an agent of human disease and may cause febrile illness as well as meningitis. In three parallel series the isolated standard type of R. helvetica, obtained from a PCR-positive I. ricinus tick, was high-passaged and propagated in a Vero cell line. By using quantitative real-time PCR, the generation time from inoculation to stationary phase of growth was calculated to 20-22 h. In the static cultivation system the stationary phase was observed from the seventh day after inoculation, and there was no observed degradation of R. helvetica DNA during the 14 days studied. Microscopy showed that the organisms invaded the host cells rapidly and were primarily found free in the cytoplasm and only occasionally located in the nucleus. Four days after inoculation some of the host cells were broken and many indifferent stages of cytoplasmic organic decomposition were seen. However the R. helvetica organism did not show any morphologic alterations and the number of organisms was stable after the replication peak which may indicate that R. helvetica is adapted to growth in a Vero cell line and/or that the phase of degradation occurs later than the 14 days studied. The findings differ from what has been reported for other rickettsiae of the spotted fever group and may be of importance for invasiveness and virulence of R. helvetica.

Rickettsia helvetica in patient with meningitis, Sweden, 2006.

Pathogenicity of Rickettsia helvetica is relatively unknown. We isolated a spotted fever group rickettsial organism from a patient with subacute meningitis. Nucleotide sequences of the 16S rRNA, ompB, and 17kDa genes identified the isolate as R. helvetica. This organism may be associated with serious infections such as central nervous system disorders.

Dissemination of spotted fever rickettsia agents in Europe by migrating birds.

Migratory birds are known to play a role as long-distance vectors for many microorganisms. To investigate whether this is true of rickettsial agents as well, we characterized tick infestation and gathered ticks from 13,260 migratory passerine birds in Sweden. A total of 1127 Ixodes spp. ticks were removed from these birds and the extracted DNA from 957 of them was available for analyses. The DNA was assayed for detection of Rickettsia spp. using real-time PCR, followed by DNA sequencing for species identification. Rickettsia spp. organisms were detected in 108 (11.3%) of the ticks. Rickettsia helvetica, a spotted fever rickettsia associated with human infections, was predominant among the PCR-positive samples. In 9 (0.8%) of the ticks, the partial sequences of 17kDa and ompB genes showed the greatest similarity to Rickettsia monacensis, an etiologic agent of Mediterranean spotted fever-like illness, previously described in southern Europe as well as to the Rickettsia sp.IrITA3 strain. For 15 (1.4%) of the ticks, the 17kDa, ompB, gltA and ompA genes showed the greatest similarity to Rickettsia sp. strain Davousti, Rickettsia japonica and Rickettsia heilongjiangensis, all closely phylogenetically related, the former previously found in Amblyomma tholloni ticks in Africa and previously not detected in Ixodes spp. ticks. The infestation prevalence of ticks infected with rickettsial organisms was four times higher among ground foraging birds than among other bird species, but the two groups were equally competent in transmitting Rickettsia species. The birds did not seem to serve as reservoir hosts for Rickettsia spp., but in one case it seems likely that the bird was rickettsiemic and that the ticks had acquired the bacteria from the blood of the bird. In conclusion, migratory passerine birds host epidemiologically important vector ticks and Rickettsia species and contribute to the geographic distribution of spotted fever rickettsial agents and their diseases.

Seroprevalence of Rickettsia spp. infection among tick-bitten patients and blood donors in Sweden.

Serum samples from 236 Swedish patients with symptoms of infectious disease appearing after a tick bite were analysed for the presence of antibodies to Rickettsia helvetica, the only rickettsial species so far isolated from ticks in Sweden. Of these subjects, 137 had tested seropositive for Borrelia burgdorferi. For control purposes, sera from 161 healthy blood donors were examined. A total of 10/397 samples (2.6%) showed IgG-antibodies to R. helvetica at or above a titre of 1/80 as cut-off. 6/137 (4.4%) belonged to the Borrelia positive group, 3/99 (3.0%) to the tick-bitten but Borrelia negative group and 1/161 (0.6%) to the control group. The difference between the tick-exposed groups and the control group was significant in Pearson's 2-sided chi(2) test. In 1 serum sample the presence of antibodies to R. helvetica was further confirmed by Western immunoblot. The study shows that infection with Rickettsia spp. as well as coinfection with Lyme borreliosis needs to be considered in the diagnosis of tick-transmitted infections in Sweden. Owing to a known occurrence of immunological cross-reactivites, however, the results must be cautiously interpreted with regard to species of Rickettsia involved.