In vitro regulation of the seq and sek staphylococcal enterotoxin genes among four allelic variants

Enterotoxins;Staphylococcus

Sammons, LindsaySchwan, William ;

University of Wisconsin

关键词: Enterotoxins;    Staphylococcus;   

Others  :  https://minds.wisconsin.edu/bitstream/handle/1793/49103/SammonsLindsay2010.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: University of Wisconsin

【 摘 要 】

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is considered to be more virulent than hospital-associated MRSA, presumably because it possesses additional, unidentified virulence factors. Two virulence proteins epidemiologically important to CA-MRSA are staphylococcal enterotoxins Seq and Sek. Four allelic variants of the seq/sek locus exist with type 4 being exclusive to the USA300 CA-MRSA strain type. Detection of seq and sek from a group of clinical methicillin-sensitive S. aureus (MSSA), clinical MRSA, and commensal nasal isolates revealed a high prevalence of these genes within CA-MRSA compared to other S. aureus cohorts. Furthermore, CA-MRSA displayed seq/sek allele types 3 and 4 exclusively. In vitro expression analysis of seq and sek among all four allele types was performed. Co-transcription of the enterotoxins was revealed for all allele types. Quantitative analysis showed very low overall expression of seq and sek during growth. The lowest expression occurred during the stationary phase for all allele types, while various strain- and allele-specific levels of absolute expression existed. When comparing all four allele types, the lowest seq and sek expression occurred in allele type 3, while the highest expression of seq occurred in allele type 4, suggesting a potential role in the virulence of the USA300 strain type