Proteomic Characterization of Lytic Bacteriophages of Staphylococcus aureus Isolated from Sewage Affluent of India

Abstract

Staphylococcus aureus is a Gram-positive bacterium that causes a variety of diseases, including bovine mastitis, which has severe economic consequences. Standard antibiotic treatment results in selection of resistant strains, leading to need for an alternative treatment such as bacteriophage therapy. Present study describes isolation and characterization of a staphylococcal phage from sewage samples. S. aureus isolates obtained from microbial type culture collection (MTCC), Chandigarh, India, were used to screen staphylococcal phages. A phage designated as ΦMSP was isolated from sewage samples by soft agar overlay method. It produced clear plaques on tryptone soya agar overlaid with S. aureus. Transmission electron microscopy revealed that the phage had an icosahedral symmetry. It had 5 major proteins and possessed a peptidoglycan hydrolase corresponding to 70 kDa. ΦMSP infection induced 26 proteins to be uniquely expressed in S. aureus. This phage can be proposed as a candidate phage to treat staphylococcal infections.

Figure 1

Secondary streaking from the plaques of ΦMSP on a lawn of S. aureus showing lines of clearance.

Figure 2

TEM images of bacteriophage ΦMSP. Bar, 100 nm.

Figure 3

SDS-PAGE analysis of phage proteins (M: protein ladder; 1, 2: ΦMSP proteins).

Figure 4

2DE gels showing proteomes of Staphylococcus aureus (s) and phage infected Staphylococcus aureus (s + p).

Figure 5

Zymogram gels of ΦMSP phages (M: prestained protein ladder (PureGene, USA); 1, 2: peptidoglycan hydrolase).