Biofilm Formation in Clinical Isolates of S. aureus is Associated with Presence of Device and Dissemination of Infection

Introduction: Biofilms are complex microbial communities attached to abiotic or biotic surfaces. These communities produce their own extracellular matrix, where they interact with one another and with the environment. Aim: To observe the biofilm formation isolates of Staphylococcus aureus from South Brazil. Materials and Methods: A total of 126 consecutive S. aureus isolates were collected, causing a variety of infections at a tertiary hospital from 2011 to 2014. We investigated biofilmforming ability by using a microtiter plate assay (crystal violet method) and compared the clinical characteristics and outcomes of infected patients with biofilm-forming ability. The following clinical characteristics were evaluated: presence of polymicrobial infection; presence of another micro-organism (in another clinical material at the same time); recurrence of infection; presence of device and site of infection. Results: Biofilm forming bacteria were categorized as high producers (n=46, 36.5%), moderate producers (n=59, 46.8%) and weak producers or non-producers (n=21, 16.7%). The presence of another microorganism isolated in the same day in another clinical specimen was significantly associated with biofilm-formation (p