The antibacterial activity of ZZ1 was highest against the strain AB09V, followed by AB0902 and then AB0901, based on the minimum

phage concentration required to form clear spots at 37°C. The natural resistance mechanisms of AB0901 and AB0902 against ZZ1 are worth further investigation in future studies. With respect to its life cycle in the sensitive strain AB09V, ZZ1 proliferates efficiently, with a short latent period (9 min), a large burst size (200 PFU/ml), and a high adsorption rate. Remarkably, only less than 50 CFU/ml of the AB09V cells remained viable 30 min after PARP assay AB09V cells were mixed with ZZ1 particles at a multiplicity of infection (MOI) of 10 at 37 °C. Moreover, ZZ1 exhibited the most powerful antibacterial activity at temperatures ranging from 35°C to 39°C, suggesting that the phage would be highly effective when placed inside the body at normal or near normal body temperature. In addition, ZZ1 was stable over a wide pH range (4-9) and was strongly resistant to heat. All of these features have implications for the use of this phage as a stable therapeutic agent for the treatment of A. baumannii infections, especially Q VD Oph those caused by the strain most sensitive to the phage, AB09V. The differences in the antibacterial activity of ZZ1

against the DMXAA research buy strains tested will be the focus of our future research both in vitro and in vivo. Conclusions This study provides information about a novel virulent A. baumannii phage. Our future research will examine

the application of this characterized phage in treating infections by A. baumannii clinical isolates both in vivo and in vitro. Methods Bacterial strains and Identification Twenty-three clinical strains of A. baumannii were used in this study for phage isolation and phage host investigation. All of these strains were isolated from the sputum of hospitalized patients at the Henan Province People’s Hospital in Zhengzhou, China. After obtaining the approval of the Life Science Ethics Committee of Zhengzhou University and written informed consent, sputum samples were collected for the purposes of why this study. The automated system BD Phoenix (Becton Dickinson Diagnostic Systems, Sparks, MD, USA) was used on clinical samples for the identification of bacteria and for antibiotic susceptibility tests. Only 3 of the 23 strains could be lysed by ZZ1; these were lysed to varying degrees. Therefore, the 3 strains were designated AB09V, AB0901, and AB0902 in our nomenclature. The 3 strains selected for use in this study were further confirmed as A. baumannii using sequence information derived from their 16 S rRNA gene. Briefly, bacterial DNA was isolated as previously described [24]. The extracted DNA was used as the PCR template to amplify the 16 S ribosomal RNA coding regions. The ClustalX 2.0 program and Oligo 4.0 primer analysis software were used for universal primer design based on homology profiles among the 16 S rRNA genes of A.