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The ability of biofilm formation in methicillin-resistant Staphylococcus aureus (MRSA) causes significant mortality and morbidity in wound infections. Nanoparticles because of the drug concentration increment at the point of contact of nanoparticles and bacteria, and slower release of the drug at the desired location are considered as proper tools to overcome the therapeutic problem of antimicrobial-resistant infections. This study was aimed to evaluate the anti-biofilm activity of cefazolin-loaded nanoparticles against MRSA isolates. The 27 clinical isolates of MRSA were collected from patients with pressure sores and diabetic ulcers referred to Loghman Hospital in Tehran—Iran. MRSA isolates were detected by polymerase chain reaction (PCR) and biochemical tests. Cefazolin-loaded niosome was synthesized using the thin-film hydration method and were characterized by zeta potential measurement and transmission electron microscopy (TEM). The round-shaped cefazolin-loaded niosomes had a diameter of 100 nm and a −63 mV zeta potential. The cefazolin-containing niosomes removed 1, 3, and 5 d old biofilms at the concentration of 128 µg ml−1, 128 µg ml−1, and 256 µg ml−1, respectively. Histological results indicated that BALB/c mice receiving cefazolin-loaded niosomes were treated effectively faster than those treated by cefazolin or untreated group. In conclusion, the cefazolin-loaded niosome could be considered as a promising candidate for the treatment of biofilm-mediated infections of MRSA.

Introduction: We assessed whether 16S rDNA and gyrB gene sequences, alone or combined, were suitable for determining the phylogenetic relationship among Salmonella enterica strains isolated from Tehran, Iran.  Patients over five years of age enrolled in an acute diarrheal surveillance project in Tehran province between May 2004 and October 2006 were selected as our study group.  Methodology: 16S ribosomal DNA (rDNA) and gyrB genes from 40 Salmonella isolates obtained from patients with acute diarrhea were sequenced and the data was used to generate phylogenetic trees that facilitated isolate comparison. Results: Salmonella strains clustered into five to seven phylogenetic groups, dependent on analysis of 16S rDNA (1546 bp), gyrB (1256 bp) or a combination of the two genes.  By 16S rDNA sequence analysis, only strains of Salmonella enterica  serovar Typhi ( S. Typhi)  clustered exclusively together.  gyrB sequences permitted clustering of all the S. Typhi and S. Paratyphi A isolates, and clustering of S. Enteritidis into two separate but exclusive groups.  Concatenation of the two data sets did not significantly improve the resolution of the strains compared to the gyrB gene.  None of the analyses completely resolved S. enterica Paratyphi B and C into mutually exclusive groups.   Conclusion: Sequencing of gyrB represents a potentially useful tool for determining the phylogenetic relationship of S. enterica strains in Tehran, Iran. Genetic analysis of the 16S rRNA gene alone or in combination with gyrB did not increase the resolution between serotypes of S. enterica.  We speculate that inclusion of additional genetic markers would improve the sensitivity of the analysis.

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