Isolation and characterization of novel giant Stenotrophomonas maltophilia phage phiSMA5.
Stenotrophomonas maltophilia is one of the most prevalent opportunistic bacteria causing nosocomial infections. It has become problematic because most of the isolates are resistant to multiple antibiotics, and therefore, development of phage therapy has attracted strong attention. In this study, eight S. maltophilia phages were isolated from clinical samples including patient specimens, catheter-related devices, and wastewater. These phages can be divided into four distinct groups based on host range and digestibility of the phage DNAs with different restriction endonucleases. One of them, designated phiSMA5, was further characterized. Electron microscopy showed it resembled Myoviridae, with an isometric head (90 nm in diameter), a tail (90 nm long), a baseplate (25 nm wide), and short tail fibers. The phiSMA5 double-stranded DNA, refractory to digestion by most restriction enzymes, was tested and estimated to be 250 kb by pulsed-field gel electrophoresis. This genome size is second to that of the largest phage, phiKZ of Pseudomonas aeruginosa. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, 25 virion proteins were visualized. N-terminal sequencing of four of them suggested that each of them might have had its N terminus cleaved off. Among the 87 S. maltophilia strains collected in this study, only 61 were susceptible to phiSMA5, indicating that more phages are needed toward a phage therapy strategy. Since literature search yielded no information about S. maltophilia phages, phiSMA5 appears to be the first reported.
Chang
Hsiao-Chuan
HC
Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan.
Chen
Chiy-Rong
CR
Lin
Juey-Wen
JW
Shen
Gwan-Han
GH
Chang
Kai-Ming
KM
Tseng
Yi-Hsiung
YH
Weng
Shu-Fen
SF
D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D016679:Genome, Viral; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006801:Humans; D008854:Microscopy, Electron; D020615:Stenotrophomonas maltophilia / Q000302:isolation & purification / Q000472:pathogenicity / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000302:isolation & purification
D004279:DNA, Viral; D014764:Viral Proteins