Biofilm and the role of the ica operon and aap in Staphylococcus epidermidis isolates causing neurosurgical meningitis

Fifty-five Staphylococcus epidermidis isolates, classified as contaminants or causing device-related meningitis, from external ventricular drain (EVD) and non-EVD cerebrospinal fluid specimens were characterized. Thirty-three of 42 (78.6%) meningitis isolates were PCR-positive for ica and aap , known determinants of polysaccharide- and protein-mediated biofilm production, whereas five of 13 (38.5%) contaminants were ica - and aap -negative; 71.4% of meningitis isolates and 84.6% of contaminants produced biofilm. ica ⁺ aap ⁺ meningitis isolates produced more biofilm than ica ⁺ aap ⁻ isolates (p 0.0020). ica ⁺ aap ⁻ isolates did not produce more biofilm than ica ⁻ aap ⁺ isolates (p 0.4368). Apparently, ica and aap are associated with biofilm production in S. epidermidis device-related meningitis isolates.