[Molecular typing of Staphylococcus aureus isolated from blood on the basis of coagulase gene polymorphism and toxin genes].
BACKGROUND
Coagulase is produced by all strains of Staphylococcus aureus. The 3' coding region of the coagulase (coa) gene contains varying numbers of 81 bp tandem repeats. S. aureus produces a variety of extracellular protein toxins. Here, we typed S. aureus strains isolated from blood by coa gene restriction fragment length polymorphism (RFLP) patterns and toxin gene profiles.


METHODS
A total of 120 strains of S. aureus were isolated from blood cultures during 2003-2006 at Kangdong Sacred Heart Hospital. The isolates were typed by PCR RFLP analysis of the coa gene and by multiplex PCR for detection of genes encoding enterotoxins (sea, seb, sec, sed, and see), toxic shock syndrome toxin-1 (tst), exfoliative toxins (eta and etb), mecA and femA.


RESULTS
All the S. aureus strains were classified into 16 types on the basis of coa gene RFLP and could be further differentiated into 34 types according to the combined patterns of coa gene RFLP and toxin gene profiles. Of 85 methicillin-resistant S. aureus (MRSA) strains, 43 (50.6%) and 36 (42.4%) belonged to the RFLP pattern L5 and pattern L1, respectively. MRSA strains belonging to pattern L5 frequently carried tst (93.0%) or sec gene (81.4%), and strains belonging to pattern L1 frequently carried sea (88.9%) or see gene (44.4%). The rate of the pattern L5 in MRSA strains increased over the past few years and was higher in intensive care unit than in other wards.


CONCLUSIONS
We typed S. aureus strains isolated from blood on the basis of coa gene RFLP and toxin genes. The strains belonging to coa gene RFLP pattern L5 and L1 appeared to be the major types of MRSA isolasted from bacteremia and revealed specific toxin gene profiles according to the coa gene RFLP patterns.
Kim
Yong Kyun
YK
Department of Laboratory Medicine, Hallym University College of Medicine, Seoul, Korea.
Kim
Jae Seok
JS
Kim
Han Sung
HS
Song
Wonkeun
W
Cho
Hyoun Chan
HC
Lee
Kyu Man
KM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D003030:Coagulase / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D016106:Methicillin Resistance / Q000235:genetics; D008875:Middle Aged; D046915:Penicillin-Binding Proteins; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000235:genetics / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D014118:Toxins, Biological / Q000235:genetics*; D055815:Young Adult
D001426:Bacterial Proteins; D003030:Coagulase; D046915:Penicillin-Binding Proteins; D014118:Toxins, Biological; C487789:mecA protein, Staphylococcus aureus