Legionella pneumophila is an important etiological agent in both hospital and community acquired pneumonia. The sensitivity of culture for isolation of L. pneumophila from clinical specimens is low and time consuming. Similar problem also exists when the method of direct immunofluorescence is used. To detect this organism quantitatively from respiratory specimens, a Taq Man based real-time PCR targeting the mip sequence was developed. Both real-time PCR and culture methods were applied on 262 respiratory specimens from 262 ICU patients with pneumonia admitted to 5 different hospitals in Tehran. The results of real-time PCR were compared with those obtained by culture. Real-time PCR and culture found 12 and 4 specimens, respectively, as positive for L. pneumophila. Its technical specificity (100%) was checked against a panel of microorganisms consisting of both Gram-positive and Gram-negative bacteria. Our real-time PCR assay showed high sensitivity (100%) and specificity (96.9%) and could detect 200 organisms per ml from respiratory specimens. Using real-time PCR as a screening method, the frequency of nosocomial pneumonia with L. pneumophila at Tehran hospitals was estimated as 4.58%.
Background: Staphylococcus aureusis a serious agent that often colonize dairy products all over the world. Staphylococcal enterotoxins are the essential causes of food poisoningin human societies. Enterotoxin type A is an importantstaphylococcal exotoxin. Objectives: The aim of present study was to detect the enterotoxin producing Staphylococcus.aureus within different dairy products collected from Tehran, Iran. Materials and Methods: Two hundreds twenty dairy products samples were collected from local dealers across the city. The samples were first screened for S. aureus contaminations. All isolated strains of S. aureus were then investigated for enterotoxin a gene, usind spesific primer sets. Results: Staphylococcus aureus was isolated from 43% of dairy samples: 22% from milk and 18% from cheese samples. The SEA genes were detected in 10 isolates (22%) originated from raw milk and in two isolates (25%) from domestic cheese. Conclusions: Since, the staphylococcal enterotoxins are heat stable, heat had no effect on the toxicity of the enterotoxins within positive samples. Our primer stets confirmed previous studies that introduced PCR as rapid, sensitive, and specific method for dairy products screening system. Our data showed that routine screening and surveillance is vital for different food materials including dairy products.
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