Efficacy of Lytic Bacteriophage Preparation in Reducing Salmonella In Vitro, on Turkey Breast Cutlets, and on Ground Turkey.

The efficacy of the recently approved Salmonella lytic bacteriophage preparation (SalmoFresh) in reducing Salmonella enterica serotype Heidelberg on turkey breast cutlets and ground turkey was evaluated. In a broth model assay, the phage preparation completely inhibited the growth of four S. enterica serotypes (Salmonella Enteritidis, Salmonella Heidelberg, Salmonella Kentucky, and Salmonella Typhimurium) at 37°C at a multiplicity of infection of 10,000 PFU/CFU. At 4°C in 0.1% peptone water (PW), phage treatment at a multiplicity of infection of 10,000 resulted in ca. 4.0-log CFU/ml reductions of Salmonella Enteritidis, Salmonella Heidelberg, and Salmonella Typhimurium. When raw turkey breast cutlets inoculated with Salmonella Heidelberg (∼10(3) CFU/g) were treated with phage preparation (10(7) PFU/g) and stored at 4°C, the phage treatment caused reductions of 0.8, 0.6, and 1.3 log CFU/g (P ≤ 0.05) of Salmonella Heidelberg on day 0, 1, and 7, respectively, compared with the counts in the control. However, no significant reduction of Salmonella Heidelberg (P > 0.05) was observed in ground turkey when turkey meat pieces inoculated with Salmonella Heidelberg were surface treated with phage preparation (10(7) PFU/g) before grinding. These findings indicate that the bacteriophage preparation was effective in reducing Salmonella on turkey breast cutlets as a surface treatment but did not cause any reduction of Salmonella Heidelberg in ground turkey.

Over-expression of gene encoding heat shock protein 70 from Mycobacterium tuberculosis and its evaluation as vaccine adjuvant.

BACKGROUND: Heat shock proteins (Hsps) are evolutionary ancient and highly conserved molecular chaperons found in prokaryotes as well as eukaryotes. Hsp70 is a predominant member of Hsp family. Microbial Hsp70s (mHsp70s) have acquired special significance in immunity since they have been shown to be potent activators of the innate immune system and generate specific immune responses against tumours and infectious agents. OBJECTIVES: The present study was aimed to clone express and purify recombinant Hsp70 from the Mycobacterium tuberculosis and characterise it immunologically. The study also aimed at determining the potential of recombinant M. tuberculosis heat shock protein (rMTB-Hsp70) as adjuvant or antigen carrier. MATERIALS AND METHODS: Cloning of M. tuberculosis heat shock protein (MTB-Hsp70) amplicon was carried out using the pGEMT-Easy vector although for expression, pProExHTb prokaryotic expression vector was used. Purification of recombinant Hsp70 was carried out by nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. For immunological characterization and determining the adjuvant effect of MTB-Hsp70, BALB/c mice were used. The data obtained was statistically analysed. RESULTS: Hsp70 gene was cloned, sequenced and the sequence data were submitted to National Center for Biotechnology Information (NCBI). Recombinant MTB-Hsp70 was successfully over-expressed using the prokaryotic expression system and purified to homogeneity. The protein was found to be immunodominant. Significant adjuvant effect was produced by the rMTB-Hsp70 when inoculated with recombinant outer membrane protein 31; however, effect was less than the conventionally used the Freund's adjuvant. CONCLUSION: Protocol standardised can be followed for bulk production of rHsp70 in a cost-effective manner. Significant adjuvant effect was produced by rMTB-Hsp70; however, the effect was than Freund's adjuvant. Further, studies need to be carried out to explore its applicability as carrier of antigen.