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.

Qnr prevalence in extended spectrum beta-lactamases [ESBLs] and none-ESBLs producing escherichia coli isolated from urinary tract infections in central of Iran

Extensive use of quinolones has been associated with raising level of resistance, in the current, we focused on assessing the prevalence of Escherichia coli resistance to quinolones and frequency of qnrA, qnrB and qnrS in non ESBLs [extended spectrum beta-lactamases] and ESBLs producing E. coli with blaSHV and blaTEM. One hundred and fifty E. coli isolates were identified during Mar. 2007 to Apr. 2008 in Milad [Tehran] hospital. They were tested for ESBLs production as well as quinolone resistance. PCR was performed for detection of blaSHV and blaTEM as well as qnrA, B and S. Of 150 isolates, forty-two [28%] ESBLs producing and one hundred and eight [72%] non-ESBLs producing E. coli were identified. 64.2% [n= 24] of E. coli producing ESBLs and 4.62% [n= 5] of non-ESBLs E. coli were resistance to ciprofloxacin. 95.2% [n= 40] and 26.1% [n= 11] of the isolates harbored blaTEM and blaSHV, respectively. 23.8% [n= 10] had both genes. 37.5% [n= 9] and 20.8% [n= 4] of ESBLs producing E. coli were positive for qnrA and qnrB respectively. qnrS was not identified in any isolate. Our study showed high frequency of ESBLs producing E. coli as well as quinolone resistance genes [qnrA, qnrB] in Milad hospital