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Background: Brucella is a gram-negative intracellular bacterium. Since Brucella brings about health and socio-economic problems, its control is of primary importance. The common method of vaccination includes using live attenuated strains of this bacterium. This study was done to evaluate the immunogenicity of Brucella aburtus P39 gene in Balb/c mice. Materials and Methods: In this experimental study, P39 gene was amplified by polymerase chain reaction (PCR) method and after extraction, it was sub-cloned to eukaryotic expression vector pcDNA3. The intramuscular injection of the obtained plasmid to the Balb/c mice was done in three stages. After the last vaccination, immunologic tests, such as proliferative response in lymphocytes, IFN- assessment, IL-5, and determination of IgG2a and IgG1, were run. Results: The level of activation in splenic lymphocytes response was 3.6 and the measured IFN- was 3 ng/ml, whereas IL-5 was insignificant. IgG2a and IgG1 titers were 1.640 and 1.40, respectively. Conclusion: The findings of the immunological analysis show the appropriate immune response in Balb/c mice model after the injection of P39 gene containing plasmid. The immune system response was in Th1 form which decreased the number of bacteria in spleen. Therefore, P39 gene is of appropriate immunogenicity and DNA vaccination is efficient in the activation of cell immune response against this bacterium.

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Background: Staphylococcus aureus is one of the important pathogens can cause infections in hospitals specially in intensive care units (ICU). It seems that nasal carriage is important risk factor for developing l infection at ICU units. This study was designed to investigate the frequency of S. aureus nasal carriage and its virulence in patients admitted to ICU units in Vali-Asr hospital at Arak university of medical sciences.

Materials and Methods: In this cross-sectional study, nasal swab samples were obtained from all the patients hospitalized in ICU unit of Vali-Asr hospital from July-December 2014 at admission. After identification, methicillin resistance and the frequency of pvl and acme genes determined by PCR. Demographic data were collected using questionnaire and were analysed using SPSS 20 software.

Results: Out of 390 patients, 81(20.8%) and 31(12.9) patients had been colonized with MSSA and MRSA, respectively. The result of culture was negative for 278 patients (71.3%). 77.4% of MRSA and 54.3% of MSSA isolates were positive for acme gene. Also, 11.11% of and 6.45% of MSSA MRSA isolates were positive for pvl gene.

Conclusion: The application of medical supportive devices like cv line, ventilator, history of surgery operation and antibiotic use significantly was associated with S. aureus nasal carriage. High prevalence of S.aureus shows that these bacteria settled in the hospital. Hence, infection control measures must be performed to reduce the risk of hospital infection.