ABSTRACT
We present draft whole-genome sequences of seven Streptococcus agalactiae strains isolated from Camelus dromedarius in Kenya and Somalia. These data are an extension to the group B Streptococcus (GBS) pangenome and might provide more insight into the underlying mechanisms of pathogenicity and antibiotic resistance of camel GBS.
GENOME ANNOUNCEMENT
The natural colonizer of human gastrointestinal and genitourinary tracts Streptococcus agalactiae, also known as Lancefield’s group B Streptococcus (GBS), is an emerging pathogen of serious clinical concern (1). As a main causative agent of meningitis, sepsis, and respiratory diseases in neonates, GBS is strongly linked to child mortality and morbidity (2). S. agalactiae has also been isolated from both healthy and diseased camels in countries from the Horn of Africa (3–7). Given the fundamental role of camels for human nutrition and financial safety in these regions, GBS-associated diseases, such as mastitis or udder abscesses resulting in significant losses in milk production, can have a devastating impact (5). Here, we report the whole-genome sequences of seven GBS strains, isolated from Kenyan and Somalian camels (Camelus dromedarius). Previous genomic analysis of these isolates by multilocus sequence typing (MLST) indicated a detached phylogenetic relationship compared to GBS strains of human or bovine origin (5). The three isolates ILRI025, ILRI030, and ILRI067 were isolated from healthy camels, while ILRI037 (causing gingivitis), ILRI054 (causing wound infection), ILRI120 (causing chronic cough), and ILRI127 (causing periarthricular abscess) were associated with disease.
Genomic DNA was extracted from a single bacterial colony cultivated on Columbia sheep blood agar using the QIAamp DSP DNA minikit (Qiagen, Hilden, Germany). DNA was fragmented by ultrasonication using the Covaris S2 instrument (Covaris, Inc., Woburn, MA, USA). Barcoded libraries were generated with the Ion fragment library kit and Ion Xpress DNA barcode adaptors (Life Technologies, Inc., Carlsbad, CA, USA). Sequencing was performed on an Ion Torrent Personal Genome Machine (PGM) system, with the Ion PGM sequencing 400 kit and the Ion 318 Chip version 2 (Life Technologies, Inc.). After sequencing, single processing and base calling were performed using Torrent Suite 3.6 (Life Technologies, Inc.), and barcode-separated FASTQ files were generated. For de novo assemblies, we used MIRA version 4.0 (8). Contigs were sorted along the already published (9) GBS genomes of ILRI112 (accession no. HF952106) and ILRI005 (accession no. HF952105) (only for isolate ILRI067) using the Move Contigs function in Mauve version 2.3.1 (10). SeqMan Pro from the Lasergene genomics package version 12.1.0 (DNAStar, Madison, WI) was used to check and manually close gaps between contigs. Genome annotation was added using the NCBI Prokaryotic Genome Annotation Pipeline (PGAP). The seven genomes displayed an overall size between 1,973,342 and 2,049,911 bp, with 1,812 to 1,954 proteins detected (Table 1).
TABLE 1 .
List of Streptococcus agalactiae draft whole genomes released to GenBank
| Strain | GenBank accession no. | Multilocus STa | Serotype | Genome size (bp) | No. of proteins |
|---|---|---|---|---|---|
| ILRI025 | NDGG00000000 | 610 | VI | 2,013,384 | 1,876 |
| ILRI030 | NDGF00000000 | 617 | VI | 1,999,626 | 1,883 |
| ILRI037 | NDGE00000000 | 612 | Ia | 2,020,002 | 1,895 |
| ILRI054 | NDGD00000000 | 615 | II | 2,021,031 | 1,867 |
| ILRI067 | NDGC00000000 | 614 | V | 1,980,469 | 1,812 |
| ILRI120 | NDGB00000000 | 618 | Ia | 2,049,911 | 1,954 |
| ILRI127 | NDGA00000000 | 613 | Ia | 1,973,342 | 1,875 |
ST, sequence type.
The draft genome sequences of cameloid GBS isolates presented here are a valuable addition to the pangenome of S. agalactiae (11). These genomic data provide a basis for the investigation of adaptive factors in GBS host colonization as well as underlying mechanisms of antibiotic resistance development and pathogenicity of camel S. agalactiae.
Accession number(s).
The annotated draft whole-genome sequences of the seven S. agalactiae isolates were deposited in GenBank under BioProject no. PRJNA382326. The accession numbers for each isolate are shown in Table 1.
ACKNOWLEDGMENTS
This work was supported by funding from the Swiss Tropical and Public Health Institute and Mabritec AG.
Footnotes
Citation Rothen J, Schindler T, Pothier JF, Younan M, Certa U, Daubenberger C, Pflüger V, Jores J. 2017. Draft genome sequences of seven Streptococcus agalactiae strains isolated from Camelus dromedarius at the Horn of Africa. Genome Announc 5:e00525-17. https://doi.org/10.1128/genomeA.00525-17.
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