Opportunistic Gram-negative rods' capability of creating biofilm structures on polivynyl chloride and styrene-acronitrile copolymer surfaces

Biofilms are highly organized microbial communities displaying high resistance to disinfectants and other external environmental factors. Medical equipment, such as stents and catheters, can be colonized by a variety of bacteria including opportunistic pathogens circulating in the environment and dangerous to immunocompromised patients. Application of materials resistant to biofilm formation will minimize the risk of patients' infection. Hence, the aim of this research was to determine the biofilm growth of environmental bacteria isolates on polyvinyl chloride and styrene-acronitrile copolymer surfaces. Nine strains (Pseudomonas aeruginosa, Burkholderia cepacia and Serratia liquefacies) isolated from cosmetics, and a reference P. aeruginosa strain ATCC 15442, were tested. The ability and dynamics of biofilm formation on intubation catheters (30°C, up to 24 h) in bacterial growth cultures (10(7)-10(8) CFU/ml) was investigated, with subsequent sonication and quantification by agar plate count method. The results indicated that all the tested bacteria expressed a strong ability for the polymer surface adhesion, reaching 4.6 to 6.7 log CFU/cm(2) after 30 minutes. Moreover, for the majority of strains, the level of 24-hour biofilm production was from 6.67-7.61 log CFU/cm(2). This research indicates that the environmental strains circulating between the cosmetics and patients may pose a threat of biofilm formation on medical equipment surfaces, and presumably in the clinical surroundings as well.