| Clinical usefulness of biofilm formation and associated genes with staphylococcus epidermidis blood isolates |
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Kyung-Hwa Park, Su Mi Choi, M.S., Sook-In Jung, Jong- Hee Shin |
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성균관 의과대학교 삼성서울병원 심혈관센터 순환기내과 |
| 원저: Staphylococcus epidermidis의 균막형성능과 관련 유전자의 임상적 유용성 |
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박경화.최수미.정숙인.신종희, Su Mi Choi, M.S., Sook-In Jung, Jong- Hee Shin |
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| Abstract |
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Background/Aims: To evaluate the clinical usefulness of biofilm production and related genes for discriminating
between pathogens, colonizers, and contaminants with Staphylococcus epidermidis blood isolates.
Methods: Forty S. epidermidis blood isolates, including 19 pathogens, 11 colonizers, and 10 contaminants, were tested.
Biofilm production was determined in 96-well polystyrene microtiter plates using crystal violet staining. Relative units
(rU), given by the optical density (OD) of the clinical isolates divided by the OD of a standard biofilm-negative strain,
were used for quantification. Polymerase chain reactions for the icaABCD, atlE, and aap genes were performed to
evaluate biofilm-related genes. The diagnostic accuracy of biofilm-related genes was assessed using the sensitivity,
specificity, and positive predictive value.
Results: Biofilm production of the catheter-related isolates, including pathogens and colonizers, was significantly greater
than that of contaminants (50% vs. 20%, p=0.012). For catheter-related isolates, rU was significantly greater for
ica-positive isolates than for ica-negative isolates (1.72¡¾0.84 vs.0.94¡¾0.22; p=0.003). The prevalence of atlE and aap did
not differ between the three groups. Seven S. epidermidis were isolated together with other microorganisms from
intravascular catheters, and their biofilm production was relatively low. The positive predictive value of icaABCD was
83% for discriminating between catheter-related isolates and contaminants.
Conclusions: Pathogens and colonizers had similar biofilm production capacities and prevalences of related genes,
whereas catheter-related isolates and contaminants differed. The biofilm production ability and presence of these genes
cannot be used for clinical decision-making regarding true pathogens. The ica operon might be useful for differentiating
between contaminants and catheter-related isolates in catheter-related infection (CRI). Further studies of other related
genes and protein expression are needed to assess the clinical usefulness of biofilm production for clinical isolates.
(Korean J Med 75:436-443, 2008) |
| Key Words:
Catheter related infection; Staphylococcus epidermidis; Biofilm |
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