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- Gullsby, Karolina
(author)
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Molecular detection and epidemiological studies of atypical bacteria causing respiratory tract infections
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Respiratory infections are common causes of morbidity and mortality. Chlamydia pneumoniae, Mycoplasma pneumoniae and Bordetella pertussis cause respiratory infection, often with similar symptoms. Molecular diagnostic methods are preferred since these bacteria are difficult to culture. The aim of this thesis was to evaluate and improve the diagnostics and knowledge of the epidemiology of these bacteria.A real-time polymerase chain reaction (PCR) method targeting the IS481 element present in the genome of B. pertussis was compared to culture and serology results, and a duplex real-time PCR method was constructed for detecting C. pneumoniae and M. pneumoniae, which was compared to two endpoint PCR methods. Both real-time PCR methods showed high sensitivity and specificity.Typing of 624 M. pneumoniae samples, collected from 1996 to 2017 from four counties, was performed by P1 typing and multiple-locus variable number tandem repeat analysis (MLVA). A polyclonal distribution of strains was seen over all epidemic periods, but strains of P1 type 2/variant 2 and MLVA types 3-5-6-2 and 4-5-7-2 predominated in 2010−2013. A shift from type 2 strains to different variant 2 strains was seen and a new variant, 2e, was detected in 2016−2017. An A2063G mutation associated with macrolide resistance was detected by a fluorescence resonance energy transfer (FRET) PCR method in one (0.16%) of 608 M. pneumoniae strains.Molecular characterisation using whole-genome sequencing of 93 B. pertussis isolates, collected between 1986 and 2016 from three counties showed that there were polyclonal strains in the county of Dalarna, Gävleborg and Uppsala in the years 2014−2016. Changes in virulence-related genes were detected: a shift from isolates harbouring the ptxP3 allele in favour of ptxP1 was seen, and almost all isolates had a disrupted prn gene. No detection of macrolide resistance in B. pertussis was detected.In conclusion, the validated real-time PCR methods for detection of B. pertussis, C. pneumoniae and M. pneumoniae have led to improved diagnostic methods for use in clinical laboratories. The molecular characterisation of M. pneumoniae and B. pertussis strains has contributed to the wider understanding of the genetic changes that has occurred over the epidemic periods, but further studies is needed.
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- Gullsby, Karolina, et al.
(author)
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Molecular typing of Mycoplasma pneumoniae strains in Sweden, 1996–2017, and the emergence of a new P1 cytadhesin gene, Variant 2e
- 2019
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In: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 57:6
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Journal article (peer-reviewed)abstract
- Mycoplasma pneumoniae causes respiratory infections, such as community-acquired pneumonia (CAP), with epidemics recurring every 3 to 7 years. In 2010 and 2011, many countries experienced an extraordinary epidemic peak. The cause of these recurring epidemics is not understood, but decreasing herd immunity and shifts in the strains' antigenic properties have been suggested as contributing factors. M. pneumoniae PCR-positive samples were collected between 1996 and 2017 from four neighboring counties inhabited by 12% of Sweden's population. A total of 578 isolates were characterized directly from 624 clinical samples using P1 typing by sequencing and multilocus variable number tandem repeat analysis (MLVA). A fluorescence resonance energy transfer (FRET)-PCR approach was also used to detect mutations associated with macrolide resistance in the 23S rRNA gene. Through P1 typing, the strains were classified into type 1 and type 2, as well as variants 2a, 2b, 2c, and a new variant found in nine of the strains, denoted variant 2e. Twelve MLVA types were distinguished, and 3-5-6-2 (42.4%), 4-5-7-2 (37.4%), and 3-6-6-2 (14.9%) predominated. Several P1 and MLVA types cocirculated each year, but type 2/variant 2 strains and MLVA types 3-5-6-2 and 4-5-7-2 predominated during the epidemic period comprising the peak of 2010 and 2011. In 2016 and 2017, type 1 became more common, and MLVA type 4-5-7-2 predominated. We also found that 0.2% (1/578) of the strains carried a macrolide resistance-associated mutation, indicating a very low prevalence of macrolide resistance in this region of Sweden.
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- Ianevski, Aleksandr, et al.
(author)
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Low Temperature and Low UV Indexes Correlated with Peaks of Influenza Virus Activity in Northern Europe during 2010-2018
- 2019
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In: Viruses. - : MDPI AG. - 1999-4915. ; 11:3
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Journal article (peer-reviewed)abstract
- With the increasing pace of global warming, it is important to understand the role of meteorological factors in influenza virus (IV) epidemics. In this study, we investigated the impact of temperature, UV index, humidity, wind speed, atmospheric pressure, and precipitation on IV activity in Norway, Sweden, Finland, Estonia, Latvia and Lithuania during 2010-2018. Both correlation and machine learning analyses revealed that low temperature and UV indexes were the most predictive meteorological factors for IV epidemics in Northern Europe. Our in vitro experiments confirmed that low temperature and UV radiation preserved IV infectivity. Associations between these meteorological factors and IV activity could improve surveillance and promote development of accurate predictive models for future influenza outbreaks in the region.
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- Ianevski, Aleksandr, et al.
(author)
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Novel activities of safe-in-human broad-spectrum antiviral agents
- 2018
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In: Antiviral Research. - : Elsevier. - 0166-3542 .- 1872-9096. ; 154, s. 174-182
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Journal article (peer-reviewed)abstract
- According to the WHO, there is an urgent need for better control of viral diseases. Re-positioning existing safe-inhuman antiviral agents from one viral disease to another could play a pivotal role in this process. Here, we reviewed all approved, investigational and experimental antiviral agents, which are safe in man, and identified 59 compounds that target at least three viral diseases. We tested 55 of these compounds against eight different RNA and DNA viruses. We found novel activities for dalbavancin against echovirus 1, ezetimibe against human immunodeficiency virus 1 and Zika virus, as well as azacitidine, cyclosporine, minocycline, oritavancin and ritonavir against Rift valley fever virus. Thus, the spectrum of antiviral activities of existing antiviral agents could be expanded towards other viral diseases.
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