Specification of Bacteriophage Isolated Against Clinical Methicillin-Resistant Staphylococcus Aureus

OBJECTIVES: The emergence of resistant bacteria is being increasingly reported around the world, potentially threatening millions of lives. Amongst resistant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) is the most challenging to treat. This is due to emergent MRSA strains and less effective traditional antibiotic therapies to Staphylococcal infections. The use of bacteriophages (phages) against MRSA is a new, potential alternate therapy. In this study, morphology, genetic and protein structure of lytic phages against MRSA have been analysed. METHODS: Isolation of livestock and sewage bacteriophages were performed using 0.4 μm membrane filters. Plaque assays were used to determine phage quantification by double layer agar method. Pure plaques were then amplified for further characterization. Sulfate-polyacrylamide gel electrophoresis and random amplification of polymorphic DNA were run for protein evaluation, and genotyping respectively. Transmission electron microscope was also used to detect the structure and taxonomic classification of phage visually. RESULTS: Head and tail morphology of bacteriophages against MRSA were identified by transmission electron microscopy and assigned to the Siphoviridae family and the Caudovirales order. CONCLUSION: Bacteriophages are the most abundant microorganism on Earth and coexist with the bacterial population. They can destroy bacterial cells successfully and effectively. They cannot enter mammalian cells which saves the eukaryotic cells from lytic phage activity. In conclusion, phage therapy may have many potential applications in microbiology and human medicine with no side effect on eukaryotic cells.

Utility of high throughput sequencing technology in analyzing the terminal sequence of caudovirales bacteriophage genome / 病毒学报

To confirm the hypothesis that the high frequency sequences of high throughput sequencing are the terminal sequences of the bacteriophage genome. An adaptor of specific sequence was linked to the end of the bacteriophage T3 genomic DNA, which was then subject to high throughput sequencing; as a control, the same T3 genomic DNA without adaptor was also analyzed by high throughput sequencing. The sequencing results were examined with bioinformatics software. Similar high throughput sequencing technique was applied to analyze the genomic sequence of N4-like bacteriophage IME11. Bioinformatics study showed that the sequences tagged with adaptors were consistent with the high frequency sequences without adaptor labeling. Our analysis also indicated that the end of the T4-like phage genome had specific sequences instead of random sequences, disagreeing with the previous assertion. Evidences were provided that N4-like bacteriophage had a particular terminal sequence: the left end of the genome was unique while the right end was permuted. The high throughput sequencing technique was convenient and practical to be used to simultaneously detect the terminal sequence and the complete sequence of bacteriophage genome.