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  Background and Objective: Staphylococcus aureus is known as an important pathogen causing a variety of bacterial infections. Treatment of this bacterium with antibiotics has led to antibiotic-resistancey, especially against methicillin (MRSA) and more recently rare resistance against vancomycin. The aims of this study were to determine nasal carriage rates of S. aureus in Meshgin Shahar Valiasr hospital’s personnel and to determine antibiotic-resistance patterns in the mentioned isolates.

  Methods: Staphylococcus aureus isolates were collected from the nose of 200 hospital personnel in Meshgin Shahar Valiasr hospital in a 2 month period in 2006. Antibiotic sensitivity of the collected strains were tested against antibiotics used in routine treatment of S. aureus infections. Oxacillin agar was also used to screen for MRSA according to NCCLS recommendation.

  Results: Our results showed there were 45% and 16% nasal carrier rate for S. aureus and MRSA (methicillin resistant staphylococcus aureus) strains, respectively in hospital personnel. Thirty two isolates were able to grow in oxacillin agar media, indicating 35% MRSA strains. Antibiotic resistant pattern of strains in disks method were recorded as follows: 35% to oxacillin, 97.8% to penicillin, 34% to erythromycin, 2.1% to chloramphenicol, 39.36% to tetracycline, 11.7% to gentamicin, 30.85% to trimetohoprim sulfamethoxazol and 19% to clindamycin. All of the isolates were sensitive to vancomycin and ciprofloxacin.

Conclusion: In this study, nasal carriage rate of Staphylococcus aureus among hospital Personnel was more than community expected rate (%40) and lower than hospital expeeted rate (%50-80). All of the test strains were sensitive to Vancomycin.

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 Background and objectives: Long term exposure to high levels of cement dust is one of the most important environmental risk factors in cement industries that adversely affect employee's respiratory system. Provided that achieving sustainable development mainly relies on healthy workers, this study aimed at assessing cement dust concentration and its free SiO₂ content in an Iranian Portland Cement Industry.

 Methods: In a cross - sectional study, airborne dust levels was investigated by collecting 64 personal and 35 environmental samples at both inhalable and respirable dust sizes. Dust concentrations were determined by deploying personal samplers in the breathing zone of workers. SiO₂ fractions were also measured in 4 samples collected from different part of the factory.

 Results: Arithmetic average concentrations of inhalable and respirable dust in personal sampling campaign were 58 and 13 mg m^-3, respectively. Respective values for inhalable and respirable dust in environmental sampling campaign were 154 and 27 mg m^-3. Dust concentrations in 90% of environmental samples and 80% of personal samples exceeded those occupational exposure limit values set for inert dusts i.e. Portland Cement. The average free SiO₂ fraction in analyzed samples was 2.86% varying from 2.33% in "packing and loading" area to 3.67 % in "raw mill" section.

  Conclusion: Free SiO₂ fraction as well as the concentrations of cement dust in this study is much higher than those of occupational exposure limit proposed by Iranian Technical Committee of Occupational Health.