GENOMICS, TRANSCRIPTOMICS, PROTEOMICS Characterization of lytic Pseudomonas aeruginosa bacteriophages via biological properties and genomic sequences Natia Karumidze & Julie. A. Thomas & Nino Kvatadze & Marina Goderdzishvili & Kevin W. Hakala & Susan T. Weintraub & Zemphira Alavidze & Stephen C. Hardies Received: 28 February 2012 / Revised: 16 April 2012 / Accepted: 17 April 2012 / Published online: 6 May 2012 # Springer-Verlag 2012 Abstract Pseudomonas aeruginosa is an important cause of infections, especially in patients with immunodeficiency or diabetes. Antibiotics are effective in preventing morbidity and mortality from Pseudomonas infection, but because of spreading multidrug-resistant bacterial strains, bacterioph- ages are being explored as an alternative therapy. Two newly purified broad host range Pseudomonas phages, named vB_Pae-Kakheti25 and vB_Pae-TbilisiM32, were characterized as candidates for use in phage therapy. Morphology, host range, growth properties, thermal stabili- ty, serology, genomic sequence, and virion composition are reported. When phages are used as bactericides, they are used in mixtures to overcome the development of resistance in the targeted bacterial population. These two phages are representative of diverse siphoviral and podoviral phage families, respectively, and hence have unrelated mechanisms of infection and no cross-antigenicity. Composing bactericidal phage mixtures with members of different phage families may decrease the incidence of developing resistance through a common mechanism. Keywords Pseudomonas aeruginosa . Bacteriophage . Phage therapy . Host range . Phage resistance Introduction P. aeruginosa causes a variety of nosocomial infections, including pneumonia, urinary tract infections, infected burn wounds, and bacteremia. Infections with this pathogen are frequent in patients with immune deficiency or diabetes. It is the primary pathogen in approximately a quarter of all patients who die of sepsis (Young 1984). P. aeruginosa is the most common hospital-acquired infection and has mor- tality rates ranging from 18% to 61% (Traugott et al. 2011). It is particularly notorious for introduction into patients in intensive care units through contamination of catheters and ventilators. P. aeruginosa is the most common respiratory infection in the genetic disorder cystic fibrosis (Bendiak and Ratjen 2009). Infections tend to become chronic as the infecting strain converts to a mode of colonization including production of a biofilm. Once infections reach this chronic status, they are nearly impossible to clear with antibiotic treatment. Eighty percent of cystic fibrosis patients are infected by P. aeruginosa by adulthood, and mortality is essentially tripled in chronically infected patients. P. aeruginosa produces a variety of virulence factors, in- cluding enzymes that promote tissue invasion and extracellular polymers that form the biofilm (Pollack 1984). The latter impedes attack by antibodies and host phagocytes, and impedes access by some antibiotics. Biofilm formation appears to be N. Karumidze : N. Kvatadze : M. Goderdzishvili : Z. Alavidze Eliava Institute of Bacteriophages, Microbiology and Virology, Tbilisi, Georgia N. Karumidze Ilia State University, Tbilisi, Georgia J. A. Thomas School of Medicine, University of Maryland Baltimore, Baltimore, MD 21201, USA K. W. Hakala : S. T. Weintraub : S. C. Hardies (*) Department of Biochemistry, MSC 7760, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX, USA e-mail: hardies@uthscsa.edu Appl Microbiol Biotechnol (2012) 94:1609–1617 DOI 10.1007/s00253-012-4119-8