Assessment of ica operon carriage and biofilm production in Staphylococcus epidermidis isolates causing bacteraemia in bone marrow transplant recipients.
The clinical significance of coagulase-negative staphylococci isolated from blood culture is typically assessed on the basis of a combination of clinical and microbiological criteria. However, these criteria are difficult to apply to haematology patients who are highly immunosuppressed and from whom blood cultures are obtained most frequently through a central venous catheter. This study analysed 112 episodes of Staphylococcus epidermidis bacteraemia that occurred in 79 bone marrow transplant recipients. In 73 (65%) episodes, only one blood culture set was positive for S. epidermidis, while 39 (35%) episodes grew S. epidermidis from multiple blood cultures. Nine patients had two or more episodes of bacteraemia with the same strain, as determined by pulsed-field gel electrophoresis (PFGE). The PFGE method also showed that 34 (31%) isolates belonged to seven clusters, indicating the persistence of certain clones in the environment. Of the 109 isolates analysed, 59 (54%) produced biofilm and 91 (83.5%) carried the ica operon. Isolates that produced biofilm were observed to colonise central venous catheters faster than non-biofilm-producing isolates (18 vs. 37 days; p 0.03). No clinical features were associated with carriage of the ica operon, but the ica operon was carried more frequently by the isolates that formed clusters.
Ninin
E
E
Laboratoire de Bactériologie-Virologie-Hygiène Hospitalière, CHU Nantes, 9 Quai Moncouso, 44093 Nantes Cedex 01, France. emmanuelle.ninin@chu-nantes.fr
Caroff
N
N
Espaze
E
E
Maraillac
J
J
Lepelletier
D
D
Milpied
N
N
Richet
H
H
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000368:Aged; D016470:Bacteremia / Q000382:microbiology; D018441:Biofilms / Q000254:growth & development*; D016026:Bone Marrow Transplantation; D002405:Catheterization, Central Venous; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009876:Operon / Q000502:physiology*; D016133:Polymerase Chain Reaction; D011135:Polysaccharides, Bacterial; D013203:Staphylococcal Infections / Q000097:blood / Q000382:microbiology*; D013212:Staphylococcus epidermidis / Q000235:genetics* / Q000254:growth & development* / Q000302:isolation & purification
D018829:Adhesins, Bacterial; D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; C113579:polysaccharide intercellular adhesin