Title The Gene bap, Involved in Biofilm Production, Is Present in Staphylococcus spp. Strains from Nosocomial Infections
Author Amina Potter1, Hilana Ceotto1, Marcia Giambiagi-deMarval1, Katia Regina Netto dos Santos1, Ingolf F. Nes2, and Maria do Carmo de Freire Bastos1*
Address 1Instituto de Microbiologia Prof. Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brasil, 2Laboratory of Microbial Gene Technology, Norwegian University of Life Sciences, As N1432, Norway
Bibliography Journal of Microbiology, 47(3),319-326, 2009,
Key Words nosocomial staphylococci, bap gene, biofilm, Staphylococcus haemolyticus, Staphylococcus cohnii
Abstract This study analyzed ten strains of coagulase-negative staphylococci (CNS) involved in nosocomial infections in three Brazilian hospitals. Their antibiotic susceptibility profile showed that most strains exhibited multiple antibiotic resistance and possessed the mecA gene. The ability of these strains to adhere to polystyrene microtiter plates was also tested and nine of them proved to be biofilm producers at least in one of the three conditions tested: growth in TSB, in TSB supplemented with NaCl, or in TSB supplemented with glucose. The presence of the bap gene, which codes for the biofilm-associated protein (Bap), was investigated in all ten strains by PCR. All strains were bap-positive and DNA sequencing experiments confirmed that the fragments amplified were indeed part of a bap gene. The presence of the icaA gene, one of the genes involved in polysaccharide intercellular adhesin (PIA) formation, was also detected by PCR in eight of the ten strains tested. The two icaA-negative strains were either weak biofilm producer or no biofilm producer, although they were bap-positive. To our knowledge, this is the first report demonstrating the presence of the bap gene in nosocomial isolates of CNS, being also the first report on the presence of this gene in Staphylococcus haemolyticus and S. cohnii.