Search

Background: Staphylococcus aureus ST398 strains are the first clonal strains identified in relation to livestock and this clone has gained a special place due to the rapid spread of these strains all over the world. Therefore, in our study, we aimed to compare in silico the LA-MRSA ST398 and LA-MSSA ST398 strains detected in human infections and with gene sequences in open databases, LA-MRSA ST398 isolated from animals and standard MSSA and MRSA strains associated with human infections in terms of virulence and antimicrobial resistance gene markers. Materials and Methods: The strains examined in this study were 2 LA-MRSA ST398 and 2 LA-MSSA ST398, which have gene sequences detected in humans and uploaded into open databases by whole genome analysis. To compare these strains, MSSA and MRSA strains associated with human infections and LA-MRSA ST398 isolated from the animal were used. CSI phylogeny, CARD and VFanalyzer online software were used to compare evolutionary similarity, antimicrobial resistance genes and virulence factors, respectively. Results: Evolutionary similarity of human-derived ST398 LA-MRSA and LA-MSSA strains were detected in 98.1% and 94.6%, respectively. Especially macrolide-lincosamide-streptogramin and erythromycin resistance genes were found in all LA-SA-ST398 strains, while tetracycline such as tetM was added to it in LA-MRSA ST398 strains. Some virulence factors associated with binding and enzyme function were found to be inactive in ST398 strains. Conclusion: As a conclusion, it was determined that human derived LA-MRSA and LA-MSSA ST398 strains activated the virulence factors related with immun evasion, and did not use toxins as a virulence factor. In order to understand the pathogenesis of the diseases developed by these strains, we believe that analyzing the available data with newly developed molecular techniques will provide an epidemiological advantage. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the Staphylococcal enterotoxin (SE) and directly detect the five classical SEA, SEB, SEC, SED and SEE gene in Staphylococcus aureus strains from different food samples by real-time PCR. We studied totally 3650 different food samples such as milk and dairy products, meat and meat products, poultry and eggs, canned food, coffee, cocoa and derived products, honey, confectionery and bakery, ready-to-eat foods, beverages in food control laboratory. We found that a total of 36 (0.98%) S. aureus strains were isolated and only 14 (0.38%) out of 36 S. aureus strains were found to be enterotoxingenic. Milk samples were found to be most contaminant among the products. The most prevalent SE types were SEA 7 (19.4%). Commercial EIA kit results were used to compare with the real-time PCR results. SE results were found to be same with these two methods. This study showed that prevalence and type of the staphylococcal enterotoxin may vary from food to food. It is important to know this data to prevent outbreaks. Additionally, automated DNA isolation and real-time PCR methods can be performed to direct enterotoxin gene detection rapidly and reliably. This technique can be also used for food safety and clinical diagnosis applications. [ABSTRACT FROM AUTHOR]