Draft Genome Sequence of Multidrug-Resistant Cellulosimicrobium sp. Strain KWT-B, Isolated from Feces of Hirundo rustica

ABSTRACT Migratory birds have been postulated as potential spreaders of antibiotic resistance. Multidrug-resistant Cellulosimicrobium sp. strain KWT-B was isolated from the feces of Hirundo rustica. A draft genome sequence indicated that the strain harbors multidrug-resistant transporters, multidrug efflux pumps, a vancomycin-resistant protein, and metallo-beta-lactamases.

M any avian species have been found to carry antibiotic-resistant bacteria and resistance genes (1). Because of their ability to migrate to long distances in short periods, migratory birds are a possible source of antibiotic-resistant bacteria that colonize and/or infect human beings (2). Hirundo rustica (barn swallow) is the most widespread species of swallows in the world. Their global population is estimated to be approximately Ͼ190,000,000 individuals (3). In Japan, H. rustica populations migrate from Southeast Asia to the whole region during the spring and breed in and migrate back to Southeast Asia during autumn (4). This migratory population is estimated to be some hundreds of thousands of individuals. However, the incidence and type of antibiotic-resistant bacteria that are associated with migratory birds in East Asia remain unclear.
The draft genome was sequenced by 300-bp paired-end sequencing on an Illumina Miseq sequencing system (Fasmac Co. Ltd., Atsugi, Kanagawa, Japan). High-quality sequence reads (3,394,741 pairs) were assembled de novo using SPAdes version 3.6.0 (13). The final assembly of the genome produced 4,412,091 bp in 16 contigs, with an N 50 of 821,157 bp and a GϩC content of 74.6%. The assembled contigs were functionally annotated using the RAST server (14). The genomes contained 3,784 putative coding sequences (CDSs). One copy each of 23S rRNA and 16S rRNA and four copies of 5S rRNA in the draft genome were revealed. The strain KWT-B lacked detectable plasmids, but it had multidrug resistance. MIC values were Ͼ256 mg liter -1 for amikacin, 12 mg liter -1 for ciprofloxacin, 12 mg liter -1 for imipenem, 24 mg liter -1 for colistin, and 0.19 mg liter -1 for vancomycin.
The genome of strain KWT-B encodes some multidrug-resistant proteins, resistancenodulation-division (RND) family efflux transporters, Na ϩ -driven multidrug efflux pump proteins, the drug resistance transporter EmrB/QacA subfamily, two drug resistance transporter Bcr/CflA subfamilies, the multidrug efflux pump subunit AcrB, the arabinose efflux permease major facilitator superfamily (MFS), vancomycin-resistant protein W, and four metallo-hydrolase-like-metallo-␤-lactamase (MBL)-fold superfamilies. They are conserved in previously sequenced Cellulosimicrobium species (15). These results suggest that H. rustica can spread multidrug-resistant Cellulosimicrobium spp. through migration between Japan and Southeast Asia and that the bacteria can be transmitted from birds to humans and vice versa. The genome of Cellulosimicrobium sp. KWT-B will facilitate understanding of the ecology and global distribution of Cellulosimicrobium spp. via migratory birds. Studies on Cellulosimicrobium associated with swallows may help improve the understanding of the dissemination of antibiotic resistance in the environment.
Accession number(s). The draft genome sequence of Cellulosimicrobium sp. KWT-B has been deposited in the DDBJ/EMBL/GenBank with the accession number NEDO00000000.

ACKNOWLEDGMENTS
This work was supported by the JSPS grant-in-aid for scientific research (C) (15K00571).
We thank Takashi Fujimitsu and Kenji Kataoka for technical assistance during this work.