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| 2. |
- Hedberg, Sara Thulin, 1980-, et al.
(författare)
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Genetic characterisation of the emerging invasive Neisseria meningitidis serogroup Y in Sweden, 2000 to 2010
- 2011
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Ingår i: Eurosurveillance. - Saint-Maurice, France : European Centre for Disease Prevention and Control. - 1025-496X .- 1560-7917. ; 16:23
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Tidskriftsartikel (refereegranskat)abstract
- Neisseria meningitidis serogroups B and C have beenresponsible for the majority of invasive meningococcaldisease in Europe. Recently, an increase of N. meningitidisdisease due to serogroup Y has been notedin Sweden (in 2010, the proportion was 39%, with anincidence of 0.23 per 100,000 population), as well as inother northern European countries. We aimed to investigatethe clonal pattern of the emerging serogroup Yin Sweden during 2000 to 2010. The serogroup Y isolatesidentified during this time (n=85) were characterisedby multilocus sequence typing and sequencing ofthe fetA, fHbp, penA, porA and porB genes. The mostfrequent clone (comprising 28 isolates) with identicalallele combinations of the investigated genes, waspartly responsible for the observed increased numberof N. meningitidis serogroup Y isolates. It was sulfadiazineresistant, with genosubtype P1.5-2,10-1,36-2,sequence type 23, clonal complex 23, porB allele 3-36,fetA allele F4-1, fHbp allele 25 and penA allele 22. Thefirst case with disease due to this clone was identifiedin 2002: there was a further case in 2004, six during2006 to 2007, eight during 2008 to 2009, with a peakof 12 cases in 2010. An unusual increase of invasivedisease in young adults (aged 20–29 years) caused bythis clone was shown, but no increase in mortality ratewas observed.
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| 3. |
- Hong, Eva, et al.
(författare)
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Target Gene Sequencing To Define the Susceptibility of Neisseria meningitidis to Ciprofloxacin
- 2013
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 57:4, s. 1961-1964
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Tidskriftsartikel (refereegranskat)abstract
- Meningococcal gyrA gene sequence data, MICs, and mouse infection were used to define the ciprofloxacin breakpoint for Neisseria meningitidis. Residue T91 or D95 of GyrA was altered in all meningococcal isolates with MICs of >= 0.064 mu g/ml but not among isolates with MICs of <= 0.032 mu g/ml. Experimental infection of ciprofloxacin-treated mice showed slower bacterial clearance when GyrA was altered. These data suggest a MIC of >= 0.064 mu g/ml as the ciprofloxacin breakpoint for meningococci and argue for the molecular detection of ciprofloxacin resistance.
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| 4. |
- Titov, Leonid P., et al.
(författare)
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Evolutionary epidemiology of Neisseria meningitidis strains in Belarus compared to other European countries
- 2013
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Ingår i: Acta Microbiologica et Immunologica Hungarica. - 1217-8950. ; 60:4, s. 397-410
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Tidskriftsartikel (refereegranskat)abstract
- Introduction. Meningococcal infections are major causes of death in children globally. In Belarus, the incidence of cases and fatality rate of meningococcal infections are low and comparable to the levels in other European countries. Aim. In the present study, the molecular and epidemiological traits of Neisseria meningitidis strains circulating in Belarus were characterized and compared to isolates from other European countries. Materials and Methods. Twenty N. meningitidis strains isolated from patients (n = 13) and healthy contacts (n = 7) during 2006-2012 in Belarus were selected for multilocus sequence typing (MLST), genosubtyping and FetA typing. The STs of the Belarusian strains were phylogenetically compared to the STs of 110 selected strains from 22 other European countries. Results. Overall, eleven different genosubtypes were observed, there were seven variants of variable region of the fetA gene detected. The majority of the STs (95%) found in Belarus were novel and all those were submitted to the Neisseria MLST database for assignment. Several newly discovered alleles of fumC (allele 451) and gdh (allele 560 and 621) appeared to be descendants of alleles which are widespread in Europe, and single aroE alleles (602 and 603) occurred as a result of separate evolution. Conclusions. N. meningitidis strains circulating in Belarus are heterogeneous and include sequence types, possibly, locally evolved in Belarus as well as representatives of widespread European hyperinvasive clonal complexes.
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- Törös, Bianca, 1987-, et al.
(författare)
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Evaluation of molecular typing methods for identification of outbreak-associated Neisseria meningitidis isolates
- 2013
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 121:6, s. 503-510
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Tidskriftsartikel (refereegranskat)abstract
- It is essential in an outbreak investigation that strain characterization of Neisseria meningitidis is performed in a rapid and accurate manner. This study evaluated two new molecular typing methods, multiple- locus variable number tandem repeat analysis (MLVA) and repetitive sequence-based PCR (rep-PCR) (DiversiLab; bioMe´rieux) and compared them with current recommended methodologies. This retrospective study included 36 invasive N. meningitidis serogroup C isolates collected in Sweden 2001 through 2009 and previously subjected to outbreak investigation. All strains were typed with highly variable- MLVA (HV-MLVA) and rep-PCR. The isolates were further characterized by multilocus sequence typing (MLST) and sequencing of the fetA, fHbp, penA, porA and porB genes. The results showed that HVMLVA had the highest index of diversity (0.99) and rep-PCR had the highest congruence (40%) with the currently recommended typing methods. The HV MLVA correlated best to the spatiotemporal connections and had the overall highest Adjusted Wallace coefficients, suggesting that HV-MLVA can predict the results of the other typing methods in the study. We therefore suggest that after initial confirmation of species, serogroup and genosubtype, HV-MLVA should be used asthe most discriminatorymethod for first hand investigation of N. meningitidis serogroup C isolates.
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| 6. |
- Törös, Bianca, 1987-
(författare)
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Genome-based characterization of Neisseria meningitidis with focus on the emergent serogroup Y disease
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neisseria meningitidis, also referred to as meningococcus, is one of the leading causes of epidemic meningitis and septicaemia worldwide. Despite modern treatment, meningococcal disease remains associated with a high mortality (about 10%). Meningococcal disease is mainly restricted to specific hypervirulent lineages and specific capsular groups (serogroups), which have a changing global distribution over time. At the end of the 2000s, the previously unusual serogroup Y emerged, corresponding to half of all of the invasive meningococcal disease (IMD) cases in Sweden by the beginning of the 2010s. The aim of this thesis is to describe the emergence of serogroup Y meningococci genetically in an effort to understand some of the factors involved in the successful spread of this group throughout Sweden. In addition, genetic typing schemes were evaluated for surveillance and outbreak investigation.Our results indicate that the currently recommended typing for surveillance of meningococci could be altered to include the factor H-binding protein (fHbp). A highly variable multilocus variable number tandem repeat analysis (HV-MLVA) was able to confirm connected cases in a suspected small outbreak. In addition, a strain type sharing the same porA, fetA, porB, fHbp, penA and multilocus sequence type was found to be the principal cause of the increase in serogroup Y disease. However, a deeper resolution obtained from the core genomes revealed a subtype of this strain, which was mainly responsible for the increase. Finally, when the Swedish serogroup Y genomes were compared internationally, different strains seemed to dominate in different regions. This indicates that the increase was probably not due to one or more point introductions of a strain previously known internationally but more probably multifactorial.
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| 7. |
- Törös, B., et al.
(författare)
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Surveillance of invasive Neisseria meningitidis with a serogroup Y update, Sweden 2010 to 2012
- 2014
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Ingår i: Eurosurveillance. - : European Centre for Disease Prevention and Control (ECDC). - 1025-496X .- 1560-7917. ; 19:42, s. 25-33
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Tidskriftsartikel (refereegranskat)abstract
- An increase of invasive meningococcal disease caused by Neisseria meningitidis serogroup Y has been noted in Sweden since 2005, and to a lower extent throughout Europe. The present study describes the epidemiology of invasive N. meningitidis isolates in Sweden in the period between 2010 and 2012, with a focus on serogroup Y. We also aimed to find an optimal molecular typing scheme for both surveillance and outbreak investigations. All invasive N. meningitidis isolates in Sweden during the study period (n=208) were genetically characterised. Serogroup Y predominated with 22/57, 31/61 and 44/90 of all invasive isolates (incidence 0.23, 0.33 and 0.46 per 100,000 population) in 2010, 2011 and 2012 respectively. In each of these years, 15/22, 22/31 and 19/44 of serogroup Y isolates were genetically clonal (Y: P1.5-2,10-1,36-2: F4-1: ST-23(cc23), 'porB allele 3-36, fHbp allele 25 and penA allele 22). Our findings further support those of others that currently recommended FetA typing could be replaced by FHbp. Moreover, in line with a previous study that we conducted, the current results indicate that highly variable multilocus variable-number tandem repeat analysis (HV-MLVA) can be used as a first-hand rapid method for small outbreak investigations.
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