Análise da produção de biofilme por bactérias isoladas em uma unidade neonatal

Abstract

Neonatal infections caused by biofilm-producing microorganisms are more persistent and difficult to treat. Klebsiella spp. are important nosocomial pathogens often involved in outbreaks in Neonatal Intensive Care Units (NICUs). These pathogens are capable of producing biofilm on biotic and abiotic surfaces, increasing their permanence on the surfaces. The aim of this study was to detect biofilm production in samples of Klebsiella pneumoniae and Klebsiella oxytoca from the environment, hands of health professionals and bloodstream from a NICU. The detection of biofilm production was performed by microplate technique, using crystal violet for biomass quantification, extracellular matrix safranin and (2,3-Bis - (2- Methoxy-4-Nitro-5-Sulfophenyl) - 2H - Tetrazolium – 5 - Carboxanilide) for evaluation of metabolic activity. In addition, Colony Forming Units (CFU) were counted to quantify the number of viable cells present in the biofilm. In total, 33 samples of Klebsiella spp. were used in the study, being 28 samples of Klebsiella pneumoniae and five samples of Klebsiella oxytoca. All samples were strong biofilm producers, but 14 samples produced more biofilm than control, in at least one of the three colorimetric methods used and 15 were less efficient in this production. The biofilm production of the other samples were not statistically significant. Comparing the biofilm production produced by the two species, Klebsiella pneumoniae was more efficient in biomass and extracellular matrix production than Klebsiella oxytoca. As for the metabolic activity evaluated in the biofilm of the two species, there were no statistically significant differences, as well as the number of viable cells present in the biofilm produced by the two species. Biofilm production by Klebsiella spp. guarantees a longer permanence of these pathogens in the unit, due to the greater protection guaranteed by the extracellular matrix production. The longer the stay of these microorganisms in the unit, the greater the chance of the newborn acquiring an infection. This study shows the importance of biofilm-producing microorganisms in a NICU and the use of three colorimetric and quantitative methods for the evaluation of different biofilm parameters, which are cheap and effective tools for detecting bacterial biofilm production.