| 1. |
- Baiao, Guilherme Costa, 1984-, et al.
(författare)
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Comparative Genomics Reveals Factors Associated with Phenotypic Expression of Wolbachia
- 2021
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Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653 .- 1759-6653. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- Wolbachia is a widespread, vertically transmitted bacterial endosymbiont known for manipulating arthropod reproduction. Its most common form of reproductive manipulation is cytoplasmic incompatibility (CI), observed when a modification in the male sperm leads to embryonic lethality unless a compatible rescue factor is present in the female egg. CI attracts scientific attention due to its implications for host speciation and in the use of Wolbachia for controlling vector-borne diseases. However, our understanding of CI is complicated by the complexity of the phenotype, whose expression depends on both symbiont and host factors. In the present study, we perform a comparative analysis of nine complete Wolbachia genomes with known CI properties in the same genetic host background, Drosophila simulans STC. We describe genetic differences between closely related strains and uncover evidence that phages and other mobile elements contribute to the rapid evolution of both genomes and phenotypes of Wolbachia. Additionally, we identify both known and novel genes associated with the modification and rescue functions of CI. We combine our observations with published phenotypic information and discuss how variability in cif genes, novel CI-associated genes, and Wolbachia titer might contribute to poorly understood aspects of CI such as strength and bidirectional incompatibility. We speculate that high titer CI strains could be better at invading new hosts already infected with a CI Wolbachia, due to a higher rescue potential, and suggest that titer might thus be a relevant parameter to consider for future strategies using CI Wolbachia in biological control.
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| 2. |
- Janice, Jessin, et al.
(författare)
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Comparative genomics of closely related Wolbachia strains infecting Drosophila
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Cytoplasmic incompatibility (CI) is the most common form of reproductive manipulation induced by the vertically inherited endosymbiont Wolbachia. The phenotype causes partial or complete sterility in crosses between infected males and non-infected females, thus benefiting infected females in the population and the spread of the bacteria. Because of these properties, CI-inducing Wolbachia has been implicated as a mean for biological pest control. Although CI has been known for several decades, the first CI-associated genes, cifA and cifB, were only recently discovered. In this study, we sequenced five complete Wolbachia genomes (wSan, wYak, wTei, wAu, wMa,) and performed comparative genomic analyses between these and four previously published complete Wolbachia genomes (wRi, wNo, wHa, wMel), that have all had their CI properties tested in the same genetic host background, Drosophila simulans STC. Using these genomes, we investigate what types of genes differ between closely related Wolbachia strains and compare the sequences from some of the strains in their natural host vs. after transfer to D. simulans STC. We find that phage-associated and hypothetical genes are likely to vary more between genomes and that very few mutations have occurred when strains were transferred to D. simulans. Furthermore, we investigate the evolution of the known CI genes and take advantage of the highly similar genomes of some strains as well as their complex CI properties to identify further genes associated with both mod and resc functions of CI.
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| 3. |
- Ljungquist, Oskar, et al.
(författare)
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Nationwide, population-based observational study of the molecular epidemiology and temporal trend of carbapenemase-producing Enterobacterales in Norway, 2015 to 2021
- 2023
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Ingår i: Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin. - 1560-7917. ; 28:27, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionNational and regional carbapenemase-producing Enterobacterales (CPE) surveillance is essential to understand the burden of antimicrobial resistance, elucidate outbreaks, and develop infection-control or antimicrobial-treatment recommendations.AimThis study aimed to describe CPE and their epidemiology in Norway from 2015 to 2021.MethodsA nationwide, population-based observational study of all verified clinical and carriage CPE isolates submitted to the national reference laboratory was conducted. Isolates were characterised by antimicrobial susceptibility testing, whole genome sequencing (WGS) and basic metadata. Annual CPE incidences were also estimated.ResultsA total of 389 CPE isolates were identified from 332 patients of 63 years median age (range: 0-98). These corresponded to 341 cases, 184 (54%) being male. Between 2015 and 2021, the annual incidence of CPE cases increased from 0.6 to 1.1 per 100,000 person-years. For CPE-isolates with available data on colonisation/infection, 58% (226/389) were associated with colonisation and 38% (149/389) with clinical infections. WGS revealed a predominance of OXA-48-like (51%; 198/389) and NDM (34%; 134/389) carbapenemases in a diversified population of Escherichia coli and Klebsiella pneumoniae, including high-risk clones also detected globally. Most CPE isolates were travel-related (63%; 245/389). Although local outbreaks and healthcare-associated transmission occurred, no interregional spread was detected. Nevertheless, 18% (70/389) of isolates not directly related to import points towards potentially unidentified transmission routes. A decline in travel-associated cases was observed during the COVID-19 pandemic.ConclusionsThe close-to-doubling of CPE case incidence between 2015 and 2021 was associated with foreign travel and genomic diversity. To limit further transmission and outbreaks, continued screening and monitoring is essential.
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