Isolation and Characterization of Novel Giant Stenotrophomonas maltophilia Phage φSMA5

Abstract

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 SMA5, 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 SMA5 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, KZ 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 SMA5, indicating that more phages are needed toward a phage therapy strategy. Since literature search yielded no information about S. maltophilia phages, SMA5 appears to be the first reported.Stenotrophomonas maltophilia, previously known as Xanthomonas maltophilia (37) and Pseudomonas maltophilia (22), is an aerobic, gram-negative bacillus widespread in a variety of environments. It has been found in the environment as a growth-promoting agent in the rhizospheres of plants, as well as in soil, water, sediment, sewage, frozen foods, and some other habitats (3,8,14,20,23,25). More importantly, S. maltophilia is increasingly prevalent in hospitals as an opportunistic human pathogen causing nosocomial infections in immunocompromised individuals and involved in postoperative infections, the infections of urinary tracts and respiratory tracts, and other disease syndromes (15,20,34,40). This organism was reported to be the second most frequently isolated nosocomial bacterium after Pseudomonas aeruginosa, and its infections have a growing clinical importance (43). The prevalence of S. maltophilia in Taiwan has also been increasing. For example, among the 6,092 bacterial strains isolated from the nosocomial infections of respiratory tracts in Taichung Veterans Hospital of Taiwan in the year 2003, 451 strains (7.4%) were identified as S. maltophilia. This bacterium ranked fifth among 86 causative bacterial species, after P. aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Staphylococcus aureus (Clinical Microbiology Report, Taichung Veterans Hospital, Taichung, Taiwan, 2004). Furthermore, most of these isolates were resistant to multiple antibiotics, including imipenem (H.-C. Chang ...

Complete Genome Sequence of IME13, a Stenotrophomonas maltophilia Bacteriophage with Large Burst Size and Unique Plaque Polymorphism

“…The one-step growth curve showed it had a very big burst size which exceeded 3,000 (data not shown). A Stenotrophomonas maltophilia phage of such a big burst size had not yet been reported (3)(4)(5)7). Meantime, the phage appeared as at least three obviously different sizes of plaques on a double-layer Luria broth agar plate, a phenomenon that we had never observed on other phages.…”

LysGH15, a Novel Bacteriophage Lysin, Protects a Murine Bacteremia Model Efficiently against Lethal Methicillin-Resistant Staphylococcus aureus Infection

“…The culture was centrifuged at 4°C (10,000 ϫ g; 15 min), and the supernatant was filtered through Millipore filters (0.22-m pore size). To detect the presence of phage, spot tests were carried out as described previously (4). Phage were purified using the double-layer agar plate method (8).…”

Bacteriophages of Ralstonia solanacearum: Their Diversity and Utilization as Biocontrol Agents in Agriculture

“…These include Pseudomonas aeruginosa phage KZ (280 kbp, Mesyanzhinov et al, 2002), EL (211 kbp, Herveldt et al, 2005), and PA3 (309 kbp, Monson et al, 2011), Vibrio parahaemolyticus phage KVP40 (245 kbp, Miller et al, 2003), Stenotrophomonas maltophila phage SMA5 (250 kbp, Chang et al, 2005), and Yersinia enterocolitica phage R1-37 (270 kbp, Kiljunen et al, 2005). Jumbo phages were also reported for Sinorhizobium meliloti (phage N3, 207 kbp, Martin and Long, 1984) and Bacillus megaterium (phage G, 670 kbp, Sun and Serwer, 1997).…”