isolates [14, 15]. Using an animal model, Soothill examined phage efficacy against infections caused by A. baumannii. Specifically, tested mice survived the otherwise lethal challenge of 5 LD50 (1 × 108) cells of a virulent A. baumannii strain, when protected by as few as 102 PFU of one lytic Acinetobacter phage [16, 17]. However, to our best knowledge, no detailed characterizations on any lytic A. baumannii phages

have been reported [18, selleck inhibitor 19]. In this paper, clinical isolates of A. baumannii were collected and used as indicator hosts for screening phages in marine sediment sample. Virulent phage AB1 was isolated and characterized. The results showed phage AB1 as a double-stranded DNA bacterial virus capable of efficiently lysing A. baumannii KD311. Results Identification of A. baumannii clinical strains Before starting phage screening, clinically isolated Acinetobacter spp. strains were first confirmed the identity of the A. baumannii by using sequence information derived from their 16S rRNA gene. As described in Material and Methods, DNA fragment containing 16S rRNA gene from each clinical isolate was PCR-amplified and sequenced. The resulted sequences were deposited to GenBank and aligned to search for the most similar sequences. Five collected clinical strains (KD311, KD312, KD331, KD332,

and KD334) were PF-6463922 validated to be A. baumannii and KD335 was Stenotrophomonas maltophilia, one pathogen often isolated accompanying selleck with A. baumannii infections. Bacteriophage isolation Five A. baumannii clinical isolates were used as indicator strains for virulent bacteriophages screening from marine sediment samples. After enrichment, phage-containing samples were plated onto semi-solid agar plates with the indicator strain forming a bacterial lawn, and plaques were allowed to form by incubating at 35°C for 4 hours. Clear plaques were obtained from these samples only when strain KD311 served as the indicator, with plaques forming at size of about 1-2 mm in diameter. The

phage isolate (named AB1) Avelestat (AZD9668) was selected for further study. Restriction fragment analysis of genomic DNA Phage AB1 was amplified and its genomic DNA extracted as described. Purified genomic DNA was digested with several restriction endonucleases or their combiantions, including ApaI, BamHI, BglII, EcoRI, EcoRV, HindIII, KpnI, NcoI, PstI, PvuII, SalI, SphI, XbaI, BglII/XbaI, EcoRI/BglII, and EcoRI/XbaI, and subsequently subjected to electrophoretic analyses. As shown in Fig. 1, out of the tested enzymes, the enzyme combinations generated clear DNA patterns. Based on the digestion profiles of BglII/XbaI, EcoRI/BglII, and EcoRI/XbaI, the genome size was determined to be approximately at the range of 45.2 kb to 46.9 kb. The restriction analyses also indicated that phage AB1 was a dsDNA virus. Determination of the phage genome sequence is also underway. Figure 1 Restriction fragments analysis of phage genomic DNA.