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Genome sequence and phenotypic analysis of a first German Francisella sp. isolate (W12-1067) not belonging to the species Francisella tularensis.

Rydzewski K, Schulz T, Brzuszkiewicz E, Holland G, Lück C, Fleischer J, Grunow R, Heuner K - BMC Microbiol. (2014)

Bottom Line: Isolate W12-1067 is closely related to the recently described F. guangzhouensis species and it replicates within eukaryotic host cells.Since W12-1067 exhibits a putative new type-VI secretion system and F. tularensis subsp. holarctica was found not to be the sole species in Germany, the new isolate is an interesting species to be analyzed in more detail.Further research is needed to investigate the epidemiology, ecology and pathogenicity of Francisella species present in Germany.

View Article: PubMed Central - HTML - PubMed

Affiliation: Cellular Interactions of Bacterial Pathogens, Centre for Biological Threats and Special Pathogens, Division 2 (ZBS 2), Robert Koch Institute, Nordufer 20, Berlin 13353, Germany. heunerk@rki.de.

ABSTRACT

Background: Francisella isolates from patients suffering from tularemia in Germany are generally strains of the species F. tularensis subsp. holarctica. To our knowledge, no other Francisella species are known for Germany. Recently, a new Francisella species could be isolated from a water reservoir of a cooling tower in Germany.

Results: We identified a Francisella sp. (isolate W12-1067) whose 16S rDNA is 99% identical to the respective nucleotide sequence of the recently published strain F. guangzhouensis. The overall sequence identity of the fopA, gyrA, rpoA, groEL, sdhA and dnaK genes is only 89%, indicating that strain W12-1067 is not identical to F. guangzhouensis. W12-1067 was isolated from a water reservoir of a cooling tower of a hospital in Germany. The growth optimum of the isolate is approximately 30°C, it can grow in the presence of 4-5% NaCl (halotolerant) and is able to grow without additional cysteine within the medium. The strain was able to replicate within a mouse-derived macrophage-like cell line. The whole genome of the strain was sequenced (~1.7 mbp, 32.2% G + C content) and the draft genome was annotated. Various virulence genes common to the genus Francisella are present, but the Francisella pathogenicity island (FPI) is missing. However, another putative type-VI secretion system is present within the genome of strain W12-1067.

Conclusions: Isolate W12-1067 is closely related to the recently described F. guangzhouensis species and it replicates within eukaryotic host cells. Since W12-1067 exhibits a putative new type-VI secretion system and F. tularensis subsp. holarctica was found not to be the sole species in Germany, the new isolate is an interesting species to be analyzed in more detail. Further research is needed to investigate the epidemiology, ecology and pathogenicity of Francisella species present in Germany.

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Growth of different Francisella strains at 25, 30 and 37°C in medium T. (A) Comparison of growth of Francisella isolate W12-1067 at different growth temperatures. (B–D) Comparison of growth of Francisella isolate W12-1067 with the growth of strains Ft. novicida U112 (Ft. novicida) and F. philomiragia 25015 (F. philomiragia ATCC 25015) at 25°C (B), 30°C (C) and 37°C (D). Results are mean standard deviations of three independent experiments of duplicate samples.
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Figure 2: Growth of different Francisella strains at 25, 30 and 37°C in medium T. (A) Comparison of growth of Francisella isolate W12-1067 at different growth temperatures. (B–D) Comparison of growth of Francisella isolate W12-1067 with the growth of strains Ft. novicida U112 (Ft. novicida) and F. philomiragia 25015 (F. philomiragia ATCC 25015) at 25°C (B), 30°C (C) and 37°C (D). Results are mean standard deviations of three independent experiments of duplicate samples.

Mentions: We investigated the growth of strain W12-1067 on different agar plates and within different liquid media. Francisella sp. strain W12-1067 grew well on BCYE, GVPC and CHA plates. The isolate grew faster in medium T than in AYE medium, and it did not grow in the cell culture medium RPMI (data not shown). Whereas L-cysteine within BCYE agar plates is necessary for the growth of L. pneumophila Paris, it stimulates the growth of F. philomiragia, and the growth of strain W12-1067 was nearly similar with or without additional cysteine (see Additional file 1: Figure S1A). Growth in medium T revealed that the growth optimum of strain W12-1067 is about 30°C (Figure 2A), but growth of strains F. philomiragia and Ft. novicida in general was faster and reached a higher cell density compared to that of the growth of strain W12-1067 (Figure 2B–D). Growth of strain W12-1067 in media with NaCl was reduced from a concentration of 4–5% NaCl, which was comparable to growth of strains F. philomiragia and Ft. novicida (up to 6–7% NaCl), but more resistant than the non-halotolerant strain Ft. holarctica LVS (see Additional file 1: Figure S1B). Using the API ZYM assay kit (bioMérieux), W12-1067 showed a profile similar to F. guangzhouensis (data not shown). In contrast to F. guangzhouensis, isolate W12-1067 was negative for alkaline phosphatase activity and showed only very low activity of the acid phosphatase, which is in good agreement with only one putative phosphatase encoding gene (peg_768) present within the genome sequence (see below).


Genome sequence and phenotypic analysis of a first German Francisella sp. isolate (W12-1067) not belonging to the species Francisella tularensis.

Rydzewski K, Schulz T, Brzuszkiewicz E, Holland G, Lück C, Fleischer J, Grunow R, Heuner K - BMC Microbiol. (2014)

Growth of different Francisella strains at 25, 30 and 37°C in medium T. (A) Comparison of growth of Francisella isolate W12-1067 at different growth temperatures. (B–D) Comparison of growth of Francisella isolate W12-1067 with the growth of strains Ft. novicida U112 (Ft. novicida) and F. philomiragia 25015 (F. philomiragia ATCC 25015) at 25°C (B), 30°C (C) and 37°C (D). Results are mean standard deviations of three independent experiments of duplicate samples.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4230796&req=5

Figure 2: Growth of different Francisella strains at 25, 30 and 37°C in medium T. (A) Comparison of growth of Francisella isolate W12-1067 at different growth temperatures. (B–D) Comparison of growth of Francisella isolate W12-1067 with the growth of strains Ft. novicida U112 (Ft. novicida) and F. philomiragia 25015 (F. philomiragia ATCC 25015) at 25°C (B), 30°C (C) and 37°C (D). Results are mean standard deviations of three independent experiments of duplicate samples.
Mentions: We investigated the growth of strain W12-1067 on different agar plates and within different liquid media. Francisella sp. strain W12-1067 grew well on BCYE, GVPC and CHA plates. The isolate grew faster in medium T than in AYE medium, and it did not grow in the cell culture medium RPMI (data not shown). Whereas L-cysteine within BCYE agar plates is necessary for the growth of L. pneumophila Paris, it stimulates the growth of F. philomiragia, and the growth of strain W12-1067 was nearly similar with or without additional cysteine (see Additional file 1: Figure S1A). Growth in medium T revealed that the growth optimum of strain W12-1067 is about 30°C (Figure 2A), but growth of strains F. philomiragia and Ft. novicida in general was faster and reached a higher cell density compared to that of the growth of strain W12-1067 (Figure 2B–D). Growth of strain W12-1067 in media with NaCl was reduced from a concentration of 4–5% NaCl, which was comparable to growth of strains F. philomiragia and Ft. novicida (up to 6–7% NaCl), but more resistant than the non-halotolerant strain Ft. holarctica LVS (see Additional file 1: Figure S1B). Using the API ZYM assay kit (bioMérieux), W12-1067 showed a profile similar to F. guangzhouensis (data not shown). In contrast to F. guangzhouensis, isolate W12-1067 was negative for alkaline phosphatase activity and showed only very low activity of the acid phosphatase, which is in good agreement with only one putative phosphatase encoding gene (peg_768) present within the genome sequence (see below).

Bottom Line: Isolate W12-1067 is closely related to the recently described F. guangzhouensis species and it replicates within eukaryotic host cells.Since W12-1067 exhibits a putative new type-VI secretion system and F. tularensis subsp. holarctica was found not to be the sole species in Germany, the new isolate is an interesting species to be analyzed in more detail.Further research is needed to investigate the epidemiology, ecology and pathogenicity of Francisella species present in Germany.

View Article: PubMed Central - HTML - PubMed

Affiliation: Cellular Interactions of Bacterial Pathogens, Centre for Biological Threats and Special Pathogens, Division 2 (ZBS 2), Robert Koch Institute, Nordufer 20, Berlin 13353, Germany. heunerk@rki.de.

ABSTRACT

Background: Francisella isolates from patients suffering from tularemia in Germany are generally strains of the species F. tularensis subsp. holarctica. To our knowledge, no other Francisella species are known for Germany. Recently, a new Francisella species could be isolated from a water reservoir of a cooling tower in Germany.

Results: We identified a Francisella sp. (isolate W12-1067) whose 16S rDNA is 99% identical to the respective nucleotide sequence of the recently published strain F. guangzhouensis. The overall sequence identity of the fopA, gyrA, rpoA, groEL, sdhA and dnaK genes is only 89%, indicating that strain W12-1067 is not identical to F. guangzhouensis. W12-1067 was isolated from a water reservoir of a cooling tower of a hospital in Germany. The growth optimum of the isolate is approximately 30°C, it can grow in the presence of 4-5% NaCl (halotolerant) and is able to grow without additional cysteine within the medium. The strain was able to replicate within a mouse-derived macrophage-like cell line. The whole genome of the strain was sequenced (~1.7 mbp, 32.2% G + C content) and the draft genome was annotated. Various virulence genes common to the genus Francisella are present, but the Francisella pathogenicity island (FPI) is missing. However, another putative type-VI secretion system is present within the genome of strain W12-1067.

Conclusions: Isolate W12-1067 is closely related to the recently described F. guangzhouensis species and it replicates within eukaryotic host cells. Since W12-1067 exhibits a putative new type-VI secretion system and F. tularensis subsp. holarctica was found not to be the sole species in Germany, the new isolate is an interesting species to be analyzed in more detail. Further research is needed to investigate the epidemiology, ecology and pathogenicity of Francisella species present in Germany.

Show MeSH
Related in: MedlinePlus