Identification of bap and icaA genes involved in biofilm formation in coagulase negative staphylococci isolated from feline conjunctiva

Bap and icaA genes are commonly known to be involved in the biofilm formation. The prevalence of bap and icaA genes and biofilm formation was determined in conjunctival isolates of coagulase negative staphylococci (CNS) collected from cats. The study was conducted on 90 archival CNS isolates collected from feline conjunctiva obtained from clinically healthy cats and cats with ocular problems. Biofilm formation was examined using the microtiter plate (MTP) method. The prevalence of icaA and bap genes was determined using polymerase chain reaction (PCR). Genetic profiles of the bap-positive isolates were examined using the modified random amplified polymorphic DNA (RAPD) method. Of the 90 CNS isolates investigated, 58.9 % (53/90) were confirmed to form biofilms on a polystyrene plate after 24 h, and the intensity of the biofilm production varied strongly between positive strains. Among the biofilm-producing isolates, 24.5 % (13/53) carried the icaA gene and 3.8 % (2/53) carried the bap gene. Among the isolates that did not produce biofilms, the icaA gene and bap gene were detected in 8.1 % (3/37) and 2.7 % (1/37) of isolates, respectively. This is the first report demonstrating that CNS isolated from feline conjunctiva can potentially be a bap gene reservoir. Preliminary comparison of the genetic profiles of three bap-positive isolates collected from cats showed that each of the isolates has a different genetic background with a high similarity with the human strain of S. epidermidis.