scholarly journals The N-Acylneuraminate Cytidyltransferase Gene, neuA, Is Heterogenous in Legionella pneumophila Strains but Can Be Used as a Marker for Epidemiological Typing in the Consensus Sequence-Based Typing Scheme

2011 ◽  
Vol 49 (12) ◽  
pp. 4052-4058 ◽  
Author(s):  
C. Farhat ◽  
M. Mentasti ◽  
E. Jacobs ◽  
N. K. Fry ◽  
C. Luck
Keyword(s):  
Legionella Pneumophila ◽  
Consensus Sequence ◽  
Epidemiological Typing ◽  
Typing Scheme

Epidemiological Typing of Legionella pneumophila Serogroup 5 Strains

Legionella ◽  
2014 ◽  
pp. 364-368 ◽  
Author(s):  
Björn P. Zietz ◽  
Jutta Wiese ◽  
Hartmut Dunkelberg ◽  
P. Christian Lück ◽  
Jürgen Helbig
Keyword(s):  
Legionella Pneumophila ◽  
Epidemiological Typing

scholarly journals Evaluation of an Optimal Epidemiological Typing Scheme for Legionella pneumophila with Whole-Genome Sequence Data Using Validation Guidelines

2016 ◽  
Vol 54 (8) ◽  
pp. 2135-2148 ◽  
Author(s):  
Sophia David ◽  
Massimo Mentasti ◽  
Rediat Tewolde ◽  
Martin Aslett ◽  
Simon R. Harris ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Gold Standard ◽  
Sequence Data ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Typing Method ◽  
Content Type ◽  
Typing Scheme ◽  
Full Profile

Sequence-based typing (SBT), analogous to multilocus sequence typing (MLST), is the current “gold standard” typing method for investigation of legionellosis outbreaks caused byLegionella pneumophila. However, as common sequence types (STs) cause many infections, some investigations remain unresolved. In this study, various whole-genome sequencing (WGS)-based methods were evaluated according to published guidelines, including (i) a single nucleotide polymorphism (SNP)-based method, (ii) extended MLST using different numbers of genes, (iii) determination of gene presence or absence, and (iv) a kmer-based method.L. pneumophilaserogroup 1 isolates (n= 106) from the standard “typing panel,” previously used by the European Society for Clinical Microbiology Study Group on Legionella Infections (ESGLI), were tested together with another 229 isolates. Over 98% of isolates were considered typeable using the SNP- and kmer-based methods. Percentages of isolates with complete extended MLST profiles ranged from 99.1% (50 genes) to 86.8% (1,455 genes), while only 41.5% produced a full profile with the gene presence/absence scheme. Replicates demonstrated that all methods offer 100% reproducibility. Indices of discrimination range from 0.972 (ribosomal MLST) to 0.999 (SNP based), and all values were higher than that achieved with SBT (0.940). Epidemiological concordance is generally inversely related to discriminatory power. We propose that an extended MLST scheme with ∼50 genes provides optimal epidemiological concordance while substantially improving the discrimination offered by SBT and can be used as part of a hierarchical typing scheme that should maintain backwards compatibility and increase discrimination where necessary. This analysis will be useful for the ESGLI to design a scheme that has the potential to become the new gold standard typing method forL. pneumophila.

scholarly journals Comparison of Different PCR Approaches for Typing of Francisella tularensis Strains

2000 ◽  
Vol 38 (3) ◽  
pp. 1016-1022 ◽  
Author(s):  
V. A. de la Puente-Redondo ◽  
N. García del Blanco ◽  
C. B. Gutiérrez-Martín ◽  
F. J. García-Peña ◽  
E. F. Rodríguez Ferri
Keyword(s):  
Francisella Tularensis ◽  
Random Amplified Polymorphic Dna ◽  
Consensus Sequence ◽  
Small Variation ◽  
Enterobacterial Repetitive Intergenic Consensus ◽  
Epidemiological Typing ◽  
Francisella Novicida ◽  
Genetic Groups ◽  
Rapd Fingerprints ◽  
Special Concern

In this study, we evaluated three PCR methods for epidemiological typing of Francisella tularensis: repetitive extragenic palindromic element PCR (REP-PCR), enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR), and random amplified polymorphic DNA (RAPD) assay with both M13 and T3-T7 primers. The analysis was performed with 40 strains of F. tularensisisolated from hares, humans, ticks, and a vole. On the basis of the combination of REP, ERIC, and RAPD fingerprints, F. tularensis strains were divided into 17 genetic groups (designated A to Q), and one Francisella novicida strain was classified in group R. The F. novicida strain is of special concern, since previous genetic methods have been unable to clearly distinguish between F. tularensis and F. novicida. The F. tularensis isolates recovered from hares were included in groups A to J, M, and P; those recovered from humans were included in groups A, D, G, J, L, O, and N; those isolated from ticks were included in groups B and Q; and that recovered from a vole was in group K. The diversities calculated for the 40 F. tularensis isolates, according to Simpson's index, were 0.14 for REP-PCR, 0.52 for ERIC-PCR, 0.39 for RAPD assay with the M13 primer (RAPD/M13-PCR), and 0.65 for RAPD/T3-T7-PCR, and the diversity increased up to 0.90 when ERIC-PCR, RAPD/M13-PCR, and RAPD/T3-T7-PCR were combined. Our results suggest that although limited genetic heterogeneity among F. tularensis strains was observed, this small variation is enough to validate the PCR methods used in this study and their combinations, because they can provide safe, useful, and rapid tools for the typing of F. tularensis.

Epidemiological Typing of Legionella pneumophila in the Absence of Isolates

Legionella ◽  
2014 ◽  
pp. 152-155
Author(s):  
Norman K. Fry ◽  
Baharak Afshar ◽  
Günther Wewalka ◽  
Timothy G. Harrison
Keyword(s):  
Legionella Pneumophila ◽  
Epidemiological Typing

scholarly journals Extension of the Legionella pneumophila sequence-based typing scheme to include strains carrying a variant of the N-acylneuraminate cytidylyltransferase gene

2014 ◽  
Vol 20 (7) ◽  
pp. O435-O441 ◽  
Author(s):  
M. Mentasti ◽  
A. Underwood ◽  
C. Lück ◽  
N.A. Kozak-Muiznieks ◽  
T.G. Harrison ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Typing Scheme

scholarly journals Characterization of the Alternative Sigma Factor σ54 and the Transcriptional Regulator FleQ of Legionella pneumophila, Which Are Both Involved in the Regulation Cascade of Flagellar Gene Expression

2004 ◽  
Vol 186 (9) ◽  
pp. 2540-2547 ◽  
Author(s):  
Sebastian Jacobi ◽  
Rüdiger Schade ◽  
Klaus Heuner
Keyword(s):  
Gene Regulation ◽  
Mutant Strain ◽  
Legionella Pneumophila ◽  
Consensus Sequence ◽  
Transcriptional Regulator ◽  
Alternative Sigma Factor ◽  
Flagellar Gene ◽  
Wild Type ◽  
Interaction Domain

ABSTRACT We cloned and analyzed Legionella pneumophila Corby homologs of rpoN (encoding σ54) and fleQ (encoding σ54 activator protein). Two other genes (fleR and pilR) whose products have a σ54 interaction domain were identified in the genome sequence of L. pneumophila. An rpoN mutant strain was nonflagellated and expressed very small amounts of the FlaA (flagellin) protein. Like the rpoN mutant, the fleQ mutant strain of L. pneumophila was also nonflagellated and expressed only small amounts of FlaA protein compared to the amounts expressed by the wild type. In this paper we show that the σ54 factor and the FleQ protein are involved in regulation of flagellar gene operons in L. pneumophila. RpoN and FleQ positively regulate the transcription of FliM and FleN, both of which have a σ54-dependent promoter consensus sequence. However, they seemed to be dispensable for transcription of flaA, fliA, or icmR. Our results confirmed a recently described model of the flagellar gene regulation cascade in L. pneumophila (K. Heuner and M. Steinert, Int. J. Med. Microbiol. 293:133-145, 2003). Flagellar gene regulation was found to be different from that of Enterobacteriaceae but seems to be comparable to that described for Pseudomonas or Vibrio spp.

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