Assessment of biofilm-forming ability of coagulase-negative staphylococci isolated from contaminated platelet preparations in Canada.
BACKGROUND
Coagulase-negative staphylococci (CoNS) are the most prevalent bacterial contaminants of platelet (PLT) preparations and have been implicated in adverse transfusion reactions worldwide. The most frequently identified contaminant is Staphylococcus epidermidis, which is noted for its ability to maintain chronic hospital-acquired infections by forming biofilms as a chief virulence mechanism.


METHODS
Strains of S. epidermidis isolated from contaminated PLT preparations in Canada were distinguished via gene-specific polymerase chain reaction (PCR) with divIVA as a marker. Biofilm-forming ability was assessed by the presence of the gene icaD, slime production on Congo red agar, and biofilm formation on polystyrene surfaces. Production of polysaccharide intercellular adhesin (PIA) was resolved by immunofluorescence.


RESULTS
Eight of the 13 (62%) CoNS isolates under study were identified as S. epidermidis. Of these, four strains (50%) were classified as strong biofilm producers. Three of the four biofilm-positive strains (75%) produced slime, harbored the icaD gene, and had positive expression of PIA.


CONCLUSIONS
Despite the presumable commensal origin of the CoNS isolates, a large proportion of S. epidermidis strains demonstrated a potential for enhanced virulence. Identification of contaminant staphylococci as biofilm producers is thus relevant and informative with regard to treatment approach in the circumstance of inadvertent infection of a PLT recipient.
Greco
Carey
C
Canadian Blood Services, Ottawa, Ontario, Canada.
Mastronardi
Cherie
C
Pagotto
Franco
F
Mack
Dietrich
D
Ramirez-Arcos
Sandra
S
D016470:Bacteremia / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms; D001792:Blood Platelets / Q000382:microbiology*; D001793:Blood Preservation; D018797:Cell Cycle Proteins / Q000235:genetics; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D006801:Humans; D053657:Platelet-Rich Plasma / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000382:microbiology*; D013212:Staphylococcus epidermidis / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity; D014774:Virulence
D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D004269:DNA, Bacterial; C104636:DivIVA protein, bacteria