Cateter urinário: o tempo de exposição e calibre podem influenciar na formação de biofilme? / Catéter urinario: ¿el tiempo de exposición y calibre puede influir en la formación de biofilm? / Urinary catheter: can exposure time and gauge affect biofilm formation?

Resumo Objetivo: Avaliar a influência do tempo de exposição e calibre na formação de biofilme em cateteres urinários de Foley (CUFs). Método: Pesquisa in vitro com amostras de fragmentos de CUFs em látex siliconizado de diferentes calibres (n° 14 e n° 16 Frenchs). A urina artificial foi confeccionada, inoculada com bactérias-padrão Staphylococcus aureus (ATCC 25923) e Pseudomonas aeruginosa (ATCC 27853) e incubada a 37 °C por 24 horas e 72 horas. As análises foram realizadas por meio de cultura (carga bacteriana) e microscopia eletrônica de varredura. Resultados: Não houve diferença na carga bacteriana dos biofilmes formados nas superfícies dos CUFs com relação aos diferentes calibres (p > 0,05). Por outro lado, o tempo de exposição (24 horas e 72 horas) foi o fator determinante para formação do biofilme de P. aeruginosa nos CUFs (p < 0,05). Conclusão: O tempo de exposição influenciou a formação do biofilme de P. aeruginosa nos CUFs, independentemente dos calibres.

Resumen Objetivo: Evaluar la influencia del tiempo de exposición y calibre en la formación de biofilm en catéteres urinarios de Foley (CUFs). Método: Investigación in vitro con muestras de fragmentos de CUFs en látex siliconizado de diferentes calibres (n ° 14 y n° 16 Frenchs). La orina artificial fue confeccionada, inoculada con bacterias estándar Staphylococcus aureus (ATCC 25923) y Pseudomonas aeruginosa (ATCC 27853) e incubada a 37 °C durante 24 horas y 72 horas. Los análisis se realizaron por medio de cultivo (carga bacteriana) y microscopía electrónica de exploración. Resultados: No hubo diferencia en la carga bacteriana de los biofilmes formados en las superficies de los CUFs en relación con los diferentes calibres (p> 0,05). Por otro lado, el tiempo de exposición (24 horas y 72 horas) fue el factor determinante para la formación del biofilm de P. aeruginosa en los CUFs (p <0,05). Conclusión: El tiempo de exposición influenció la formación del biofilm de P. aeruginosa en los CUFs, independientemente de los calibres.

Abstract Objective: To assess the effects of exposure time and gauge of Foley catheters in biofilm formation. Method: In vitro study with samples of Foley catheter fragments made of siliconized latex of different gauges (#14 and #16 French gauge). Artificial urine was produced, which was inoculated with Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853) standard bacteria, incubated at 37 °C for 24 hours and 72 hours. The material was analyzed by means of culture (bacterial load) and scanning electron microscopy. Results: There was no difference in bacterial load of biofilms formed in Foley catheter surfaces with regard to different gauges (p > 0.05). On the other hand, exposure time (24 hours and 72 hours) was a determining factor for P. aeruginosa biofilm formation in Foley catheters (p < 0.05). Conclusion: Exposure time had an effect on P. aeruginosa biofilm formation in Foley catheters, regardless of gauges.

Evaluation of antimicrobial activities of minocycline and rifampin-impregnated silicone surfaces in an in vitro urinary system model

To evaluate the antimicrobial activity in urinary catheters and silicones in antibiotic-coated prosthetic urinary systems in order to reduce morbidity and mortality caused by catheter-associated infection. The study was initiated in 1993 at Houston, USA and continued in Turkey till 1996. A sterile plastic bag was used as kidney in the in vitro urinary system. Physiological renal jet streams [50cc/h] were generated with an intravenous metric pump. The temperature was kept at body temperature. The bladder drainage was achieved at the physiological drainage period of 4-6 hours during the 72-hour experiment. Silicone surfaces coated with pure silicone and impregnated with Minocycline-Rifampin were exposed to the urine contaminated with the targeted bacteria in the in vitro urinary model for 72 hours. Antimicrobial activities occurring in the Eosin methylene blue and blood agar media in the infected silicones were assessed. Minocycline-Rifampin silicone surfaces exposed to the urine contaminated with Escherichia coli and Pseudomonas aeruginosa reported reproduction. No reproduction was observed in the culture of Minocycline-Rifampin-impregnated silicone surfaces for Proteus mirabilis. The difference with the control group was regarded as statistically significant for Proteus mirabilis [p<0.005]. Minocycline-Rifampin-coated silicones were closely monitored only for Proteus mirabilis in the in vitro urinary medium. Although inhibition zones [<10mm] in the cultures were observed for Minocycline-Rifampin-coated silicones for Escherichia coli and Pseudomonas aeruginosa, but the microbial efficacy was not regarded sufficient. There is still need for evidence-based in vivo and in vitro studies where antimicrobial activity is evaluated on the surface of catheters