Draft genome sequence data of T-5 like Salmonella bacteriophage ФSP3 with demonstrated therapeutic potential.

This data article describes the complete draft genome sequence of Salmonella specific bacteriophage ΦSP3 isolated from chicken intestinal contents. The ΦSP3 genome was sequenced by paired end runs using Illumina HiSeq 2500 with 100X coverage. Phylogenetic analysis using major capsid gene and genome wide comparison were performed to understand bacteriophage evolutionary relationship. Genome sequence of bacteriophage ΦSP3 was deposited in GenBank under the accession number MG387042.

Biocontrol of Salmonella Enteritidis in spiked chicken cuts by lytic bacteriophages ΦSP-1 and ΦSP-3.

The ability of host specific bacteriophages ΦSP-1 and ΦSP-3 to lyse Salmonella in artificially contaminated cuts of pressure cooked chicken meat was evaluated at different temperatures -4 °C, room temperature (28 ± 0.5 °C) and 37 °C applying low and high multiplicity of infection (MOI). Bacteriophages were able to significantly reduce the bacterial counts at all the temperatures studied. At 4 °C, individual application of Φ SP-1 and Φ SP-3 resulted in significant drop in bacterial counts (log10 2.46 and 2.1 CFU/ml, respectively) at high MOI and (log10 0.98 and 0.52 CFU/ml, respectively) at low MOI, when compared to the untreated control on day 3. Similarly at room temperature the drop was log10 3.99 and 3.46 CFU/ml at high MOI and log10 2.51 and 2.3 CFU/ml at low MOI. At 37 °C the drop was log10 1.98 and 2.38 at high MOI and at low MOI it was log10 1.52 and 1.98 CFU/ml. Increased efficiency was observed when phages where applied as cocktail at high MOI as the bacterial counts at the end of day 3 dropped by log10 3.52 CFU/ml at 37 °C and to beyond detectable level at 4 °C and room temperature. The average reduction of bacterial load in the same group was -4 °C (79%), room temperature (92%) and 37 °C (78%).

Application of ΦSP-1 and ΦSP-3 as a therapeutic strategy against Salmonella Enteritidis infection using Caenorhabditis elegans as model organism.

The potential of Salmonella-specific phages ΦSP-1 and ΦSP-3 as biocontrol agents was studied in vitro, employing host cell lysis test and in vivo, using Caenorhabditis elegans as a model organism. For in vivo testing, stage 4 C. elegans larvae were experimentally infected with the pathogen Salmonella. Worm mortality was scored for 10 days. TD50 (the time required for 50% of the nematodes to die) of infected worms in the presence of bacteriophages was comparable to uninfected worms, and the two phages provided an increased protection than each one. This study in addition demonstrated the simplicity, elegance, and the cost effectiveness of the C. elegans model for in vivo validation.

Isolation and partial characterization of ΦSP-1, a Salmonella specific lytic phage from intestinal content of broiler chicken.

Salmonella enterica subsp. enterica serovar Enteritidis is a major causative agent of gastroenteritis with contaminated eggs and chicken meat being the major source of infection. Phages are seriously being considered as a safe and cheaper alternative to antibiotics. The intestinal content of chicken was used as source for isolating phages. Phage designated as ΦSP-1 was selected for the study. Transmission electron microscopy (TEM) of phage ΦSP-1 revealed that it belonged to family Podoviridae. The optimal multiplicity of infection (MOI) was 5 phages/cell. Latent and rise period were calculated to be 30 and 55 minutes respectively, while burst size was 44 phages/bacterial cell. The genome size of ΦSP-1 was estimated to be 86 kb from pulsed-field gel electrophoresis analysis (PFGE). The effect of different physical and chemical parameters like temperature, pH, salinity and CaCl2 were analyzed to optimize the conditions for large scale production of phages and to check the viability of ΦSP-1 under different physiochemical conditions. A temperature of 40 °C, pH 8 and 0.25 M NaCl were found to be optimum for phage adsorption and it was able to survive up to a temperature of 50 °C for 3 min. Capability to survive under hostile environmental conditions, absence of virulence genes in genome and genus specificity suggest suitability of ΦSP-1 to be used as a biocontrol agent.