Abstract
A novel lytic bacteriophage, SA11, infecting Staphylococcus aureus was isolated, and the whole genome was sequenced. It belongs to the siphoviridae based on electron microscopic observation. It has a linear double-stranded DNA genome of 136,326 bp. Genomic analysis showed that it is distantly related to Staphylococcus phages A5W, K, ISP, Sb-1, and G1.
GENOME ANNOUNCEMENT
Staphylococcus aureus is a Gram-positive bacterium acting as an opportunistic pathogen. It causes skin and soft tissue infections, often in otherwise healthy individuals (9). Methicillin-resistant Staphylococcus aureus (MRSA) was first observed in hospitals. But in the beginning of 2000, community-acquired MRSA also started to be reported (2). MRSA-related osteomyelitis (1), nasopharyngeal colonization (3), skin infections (4), food-chain animal infections (7), and infections in immunocompromised patients (8), among others, were reported. Resistance mechanisms were reviewed previously (5, 9, 10). Novel treatment options, including bacteriophages, were reviewed previously (6, 11).
We isolated bacteriophage SA11 from a wastewater treatment facility in Gwa-Chon, South Korea. The host strain used for isolation and propagation of the phage was Staphylococcus aureus ATCC 13301. The infection was strictly lytic.
The phage DNA was isolated using a phage DNA isolation kit (Norgen Biotech, Canada). Whole-genome DNA was sequenced in a Roche 454 genome sequencer, and data processing was done using the Roche GS FLX software program (v2.6) (Macrogen, South Korea).
Phage SA11 contains a linear, double-stranded DNA genome of 136,326 bp in length. The G+C content is 30.04%. There are 186 predicted open reading frames (ORFs), of which 167 encode hypothetical proteins. Based on homology search, putative functions of 19 ORFs were identified. Structural proteins include capsid protein, tail protein, major tail sheath protein, and portal protein. Nonstructural proteins include DNA helicase, DNA methylase family protein, homing endonuclease, putative endonuclease, pentapeptide repeat protein, adenine-specific methyltransferase, ribonucleoside-diphosphate reductase, transposase, phage antirepressor protein, LysM domain-containing protein, N-acetylmuramoyl-l-alanine amidase, and CHAP domain-containing protein. Many nonstructural proteins are thought to be involved in DNA replication and modification. LysM domain-containing protein, N-acetylmuramoyl-l-alanine amidase, and CHAP domain-containing proteins are thought to be involved in peptidoglycan binding and host lysis.
The analysis of the complete genomic sequence revealed that less than 21% of the genome shows any significant homology to those of previously reported Staphylococcus phages, including A5W, K, ISP, Sb-1, and G1.
Nucleotide sequence accession number.
The complete genome sequence of Staphylococcus aureus bacteriophage SA11 is available in GenBank under accession number JX194239.
ACKNOWLEDGMENTS
This study was supported by 2011 GRRC and Korea National Research Foundation grant 20120000040.
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