Open AccessVirulence Genes and Genotypic Associations in Nasal Carriage, Community-Associated Methicillin-Susceptible and Methicillin-Resistant USA400 Staphylococcus aureus Isolates
Author(s) -
Sanjay Kumar Shukla,
Mary E. Karow,
Jennifer M. Brady,
Mary E. Stemper,
Jennifer Kislow,
Natalie Moore,
Katherine Wroblewski,
PoHuang Chyou,
David M. Warshauer,
Kurt D. Reed,
Ruth Lynfield,
William R. Schwan
Publication year - 2010
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.00657-10
Subject(s) - carriage , virulence , microbiology and biotechnology , staphylococcus aureus , biology , genotype , enterotoxin , methicillin resistant staphylococcus aureus , multilocus sequence typing , staphylococcal infections , gene , medicine , bacteria , genetics , pathology , escherichia coli
It is not well understood why strains of community-associated methicillin-resistantStaphylococcus aureus (CA-MRSA), a major cause of skin and soft tissue infections, became successful so quickly, overtaking the place of methicillin-sensitiveS. aureus (MSSA) in many communities. To evaluate the genetic basis of differences in their virulence traits, 293S. aureus isolates consisting of three cohorts, genotypically defined clinical CA-MRSA (n = 77), clinical MSSA (n = 103), and nasal carriage MSSA (n = 113), collected over a 19-year period in two Midwestern states in the United States, were (i) extensively genotyped and (ii) screened for 40 known virulence genes which included those for enterotoxins, leukocidins, hemolysins, and surface proteins and several newly identified putative toxin genes from the USA400 lineage of CA-MRSA. Genotypically, nasal carriage and clinical MSSA isolates were much more diverse than was the CA-MRSA group, which was found to be of USA400 lineage only. Virulence gene profiles of the three groups showed that CA-MRSA strains harbored significantly higher percentages (≥95%;P value, <0.05) of thesea ,sec ,sec4 ,seg2 ,seh ,sek ,sel ,sel2 ,ear ,ssl1 ,lpl10 ,lukSF-PV ,lukD ,lukE , andclfA genes than did the carriage and the clinical MSSA group (range, 0% to 58%). Genes of the enterotoxin gene cluster,seg ,sei ,sem ,sen , andseo , were present in the clinical and carriage isolates but not in the CA-MRSA group. These results suggest that the presence of additional virulence factors in USA400 CA-MRSA strains compared to the nasal carriage and clinical MSSA strains probably contributed to their enhanced virulence.