Draft Genome Sequences of Five Legionella pneumophila Strains Isolated from Environmental Water Samples.

Legionella pneumophila is the causative agent of legionellosis. Here, we report the draft genome sequences of five L. pneumophila strains, Bnt314, Ofk308, Twr292, Ymg289, and Ymt294, isolated from environmental water samples. Comparative analyses of these genomes may reveal the survival mechanisms and virulence of L. pneumophila in the natural environment.

GENOME ANNOUNCEMENT

Legionella pneumophila is the most frequent cause of legionellosis in humans. L. pneumophila can withstand temperatures of 0 to 68°C and a pH range of 5.0 to 8.5 and can survive in most environments for long periods (1). Furthermore, L. pneumophila is a facultative intracellular bacterium and can survive within free-living protozoa, such as amoebae and ciliates, in environmental waters (2–4). These environmental habitats of L. pneumophila have been suggested as important evolutionary sites to develop their virulence traits in humans, although the detailed mechanisms remain largely unclear.

Previously, we isolated five L. pneumophila strains from environmental water samples (5). L. pneumophila strains Ofk308, Twr292, and Ymt294 were isolated from an Ashiyu foot spa strain Ymg289 was isolated from a water fountain, and strain Bnt314 was isolated from a pond. These strains were classified as L. pneumophila serotype I or IV. Here, we report the draft genome sequences of the five L. pneumophila strains (Table 1).

TABLE 1 

Information for draft genome sequences of five L. pneumophila strains isolated from environmental water samples

Strain	Source	Serotype	Accession no.	No. of contigs (>200 bp)	G+C content (%)	Genome size (bp)	No. of protein-coding genes
Bnt314	Pond	IV	BBUG00000000	80	38.2	3,471,799	3,105
Ofk308	Ashiyu foot spa	IV	BBUH00000000	86	38.2	3,473,188	3,104
Twr292	Ashiyu foot spa	I	BBUI00000000	66	38.2	3,394,434	3,007
Ymg289	Water fountain	I	BBUJ00000000	54	38.3	3,689,833	3,291
Ymt294	Ashiyu foot spa	I	BBUK00000000	141	38.4	3,401,814	3,076

Chromosomal DNA was extracted from an overnight culture of the five L. pneumophila strains using the DNeasy blood and tissue kit (Qiagen). Whole-genome sequencing of the five environmental strains was performed using paired-end sequencing on the Illumina MiSeq kit version 3. The sequencer produced 300-bp paired-end reads that were obtained from 550-bp inserts. The quality of the reads was checked using FastQC (http://www.bioinformatics.babraham.ac.uk/projects/fastqc/), and the raw sequences were trimmed to 250 bp using FASTX-Toolkit (http://hannonlab.cshl.edu/fastx_toolkit/). De novo genome assembly was performed using SPAdes version 3.5.0 (6). After the removal of low-coverage contigs, the resulting contigs were ordered against the complete genome of L. pneumophila subsp. pneumophila strain Philadelphia 1 chromosome (7) using the Mauve aligner (8). Genome annotation was performed using Prokka version 1.11 (9). The genome sizes and G+C contents were estimated for all contigs of each strain using G-language Genome Analysis Environment version 1.9.0 (http://www.g-language.org) (10). Among the five strains, the genome size and G+C content varied from 3.39 to 3.69 Mb and 38.2 to 38.4%, respectively (Table 1) and were close to those of the reference genome of strain Philadelphia 1. The genome statistics for the five environmental strains are summarized in Table 1.

Nucleotide sequence accession numbers.

The sequences have been deposited as whole-genome shotgun projects at DDBJ/EMBL/GenBank under the accession numbers listed in Table 1. The versions described in this paper are the first versions.