RAPD for the typing of coagulase-negative staphylococci implicated in catheter-related bloodstream infection.
OBJECTIVE
A rapid random amplification of polymorphic DNA (RAPD) technique was developed to distinguish between strains of coagulase-negative staphylococci (CoNS) involved in central venous catheter (CVC)-related bloodstream infection. Its performance was compared with that of pulsed-field gel electrophoresis (PFGE).


METHODS
Patients at the University Hospital Birmingham NHS Foundation Trust, U.K. who underwent stem cell transplantation and were diagnosed with CVC-related bloodstream infection due to CoNS whilst on the bone marrow transplant unit were studied. Isolates of CoNS were genotyped by PFGE and RAPD, the latter employing a single primer and a simple DNA extraction method.


RESULTS
Both RAPD and PFGE were highly discriminatory (Simpson's diversity index, 0.96 and 0.99, respectively). Within the 49 isolates obtained from blood cultures of 33 patients, 20 distinct strains were identified by PFGE and 25 by RAPD. Of the 25 strains identified by RAPD, nine clusters of CoNS contained isolates from multiple patients, suggesting limited nosocomial spread. However, there was no significant association between time of inpatient stay and infection due to any particular strain.


CONCLUSIONS
The RAPD technique presented allows CoNS strains to be genotyped with high discrimination within 4h, facilitating real-time epidemiological investigations. In this study, no single strain of CoNS was associated with a significant number of CVC-related bloodstream infections.
Casey
A L
AL
Department of Clinical Microbiology and Infection Control, The Queen Elizabeth Hospital, University Hospital Birmingham NHS Foundation Trust, Edgbaston, Birmingham B15 2TH, UK. anna.casey@uhb.nhs.uk
Worthington
T
T
Caddick
J M
JM
Hilton
A C
AC
Lambert
P A
PA
Elliott
T S J
TS
D000293:Adolescent; D000328:Adult; D000368:Aged; D016470:Bacteremia / Q000382:microbiology*; D015373:Bacterial Typing Techniques / Q000379:methods*; D002405:Catheterization, Central Venous / Q000009:adverse effects*; D003030:Coagulase / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods / Q000592:standards; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods* / Q000592:standards; D013203:Staphylococcal Infections / Q000382:microbiology*; D013210:Staphylococcus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification
D003030:Coagulase